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Chlorido­[5,10,15,20-tetra­kis­(quinoline-7-carboxamido)­porphinato]iron(III)

The title compound, [Fe(C84H52N12O4)Cl], crystallizes in space group C2/c. The central FeIII cation (site symmetry 2) is coordinated in a fivefold manner, with four pyrrole N atoms of the porphyrin core in the basal sites and one Cl atom (site symmetry 2) in the apical position, which completes a slightly distorted square-pyramidal environment. The porphyrin macrocycle shows a characteristic ruffled-shape distortion and the iron atom is displaced out of the porphyrin plane by 0.42 Å with the average Fe—N distance being 2.054 (4) Å; the Fe—Cl bond length is 2.2042 (7) Å. Inter­molecular C—H⋯N and C—H⋯O hydrogen bonds occur in the crystal structure.




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(2,5-Di­methyl­imidazole){N,N',N'',N'''-[porphyrin-5,10,15,20-tetra­yltetra­(2,1-phenyl­ene)]tetra­kis(pyridine-3-carboxamide)}manganese(II) chloro­benzene disolvate

In the title compound, [Mn(C68H44N12O4)(C5H8N2)]·2C6H5Cl, the central MnII ion is coordinated by four pyrrole N atoms of the porphyrin core in the basal sites and one N atom of the 2,5-di­methyl­imidazole ligand in the apical site. Two chloro­benzene solvent mol­ecules are also present in the asymmetric unit. Due to the apical imidazole ligand, the Mn atom is displaced out of the 24-atom porphyrin mean plane by 0.66 Å. The average Mn—Np (p = porphyrin) bond length is 2.143 (8) Å, and the axial Mn—NIm (Im = 2,5-di­methyl­imidazole) bond length is 2.171 (8) Å. The structure displays inter­molecular and intra­molecular N—H⋯O, N—H⋯N, C—H⋯O and C—H⋯N hydrogen bonding. The crystal studied was refined as a two-component inversion twin.




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(4-Butyl-1-ethyl-1,2,4-triazol-5-yl­idene)[(1,2,5,6-η)-cyclo­octa-1,5-diene](tri­phenyl­phosphane)iridium(I) tetra­fluorido­borate

The title compound, [Ir(C8H12)(C8H15N3)(C18H15P)]BF4, a new triazole-based N-heterocyclic carbene iridium(I) cationic complex with a tetra­fluorido­borate counter-anion, crystallizes with two cations and two anions in the asymmetric unit of space group Pc. The Ir centers of the cations have distorted square-planar conformations, formed by a bidentate (η2 + η2) cyclo­octa-1,5-diene (COD) ligand, an N-heterocyclic carbene and a tri­phenyl­phosphane ligand with the NHC carbon atom and P atom being cis. In the extended structure, non-classical C–H⋯F hydrogen bonds, one of which is notably short (H⋯F = 2.21 Å), link the cations and anions. The carbon atoms of one of the COD ligands are disordered over adjacent sites in a 0.62:0.38 ratio.




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Triaceto­nitrile­(1,4,7-trimethyl-1,4,7-tri­aza­cyclonona­ne)cobalt(II) bis­(tetra­phenyl­borate)

The title cobalt(II) complex, [Co(C2H3N)3(C9H21N3)](C24H20B)2 or [(tacn)Co(NCMe)3][BPh4]2, has been characterized by single-crystal X-ray diffraction. It incorporates the well-known macrocyclic tacn (1,4,7-trimethyl-1,4,7-tri­aza­cyclo­nona­ne) ligand, which is coordinated facially to the metal center. The complex crystallizes in space group P21/c with Z = 4. The divalent cobalt ion exhibits a six-coordinate octa­hedral geometry by one tacn and three aceto­nitrile ligands. Two non-coordinating tetra­phenyl­borate (BPh4−) anions are also present.




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Bis{(S)-(−)-N-[(2-biphen­yl)methyl­idene]-1-(4-meth­oxy­phen­yl)ethyl­amine-κN}di­chlorido­palladium(II)

The PdII complex bis­{(S)-(−)-N-[(biphenyl-2-yl)methyl­idene]1-(4-meth­oxy­phen­yl)ethanamine-κN}di­chlorido­palladium(II), [PdCl2(C22H21NO)2], crystallizes in the monoclinic Sohncke space group P21 with a single mol­ecule in the asymmetric unit. The coordination environment around the palladium is slightly distorted square planar. The N—Pd—Cl bond angles are 91.85 (19), 88.10 (17), 89.96 (18), and 90.0 (2)°, while the Pd—Cl and Pd—N bond lengths are 2.310 (2) and 2.315 (2) Å and 2.015 (2) and 2.022 (6) Å, respectively. The crystal structure features inter­molecular N—H⋯Cl and intramolecular C—H⋯Pd inter­actions, which lead to the formation of a supramolecular framework structure.




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Bis(8-hy­droxy­quinolinium) naphthalene-1,5-di­sulfonate tetra­hydrate

The inter­action between 8-hy­droxy­quinoline (8HQ, C9H7NO) and naphthalene-1,5-di­sulfonic acid (H2NDS, C10H8O6S2) in aqueous media results in the formation of the salt hydrate bis­(8-hy­droxy­quinolinium) naphthalene-1,5-di­sulfonate tetra­hydrate, 2C9H8NO+·C10H6O6S22−·4H2O. The asymmetric unit comprises one protonated 8HQ+ cation, half of an NDS2– dianion symmetrically disposed around a center of inversion, and two water mol­ecules. Within the crystal structure, these components are organized into chains along the [010] and [10overline{1}] directions through O—H⋯O and N—H⋯O hydrogen-bonding inter­actions, forming a di-periodic network parallel to (101). Additional stabilizing inter­actions such as C—H⋯O, C—H⋯π, and π–π inter­actions extend this arrangement into a tri-periodic network structure




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6-[4-(tert-Butyl­dimethyl­sil­yloxy)phen­yl]-1-oxa­spiro­[2.5]hepta­ne

The title compound, C19H30O2Si, has triclinic (Poverline{1}) symmetry at 100 K. The O atom of the epoxide group has a pseudoaxial orientation and the dihedral angle between the cyclo­hexyl and benzene rings is 85.80 (8)°. The C—O—Si—Ct (t = tert-but­yl) torsion angle is −177.40 (14)°. In the crystal, pairwise C—H⋯O links connect the mol­ecules into inversion dimers featuring R22(8) loops.




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trans-Di­aqua­tetra­kis­(tetra­hydro­furan-κO)iron(II) μ-carbonyl-tetra­deca­carbonyl­tetra­chlorido-μ-di­methyl­silanediolato-tetra­galliumtetra­iron(7 Ga–Fe)(Fe–Fe) tetra­hydro&#

The title compound, [Fe(C4H8O)4(H2O)2][Fe4Ga4(C2H6O2Si)Cl4(CO)15]·4C4H8O, consists of an iron(II) cation octa­hedrally coordinated by two water mol­ecules (trans) with four tetra­hydro­furans (THF) at equatorial sites. Two additional THF mol­ecules are hydrogen bonded to each of the water mol­ecules. The dianion of the title compound is an organometallic butterfly complex with a dimethyl siloxane core and two iron-gallium fragments. The lengths of the iron to gallium metal–metal bonds range from 2.3875 (6) to 2.4912 (6) Å.




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Bis(ethyl­enedi­ammonium) μ-ethyl­enedi­aminetetra­acetato-1κ3O,N,O':2κ3O'',N',O'''-bis­[tri­oxidomolybdate(VI)] tetra­hydrate

The title compound, (C2H10N2)2[(C10H12N2O8)(MoO3)2]·4H2O, which crystallizes in the monoclinic C2/c space group, was obtained by mixing molybdenum oxide, ethyl­enedi­amine and ethyl­enedi­amine­tetra­acetic acid (H4edta) in a 2:4:1 ratio. The complex anion contains two MoO3 units bridged by an edta4− anion. The midpoint of the central C—C bond of the edta4− anion is located on a crystallographic inversion centre. The independent Mo atom is tridentately coordin­ated by a nitro­gen atom and two carboxyl­ate groups of the edta4− ligand, together with the three oxo ligands, producing a distorted octa­hedral coordination environment. In the three-dimensional supra­molecular crystal structure, the dinuclear anions, the organo­ammonium counter-ions and the solvent water mol­ecules are linked by N—H⋯Ow, N—H⋯Oedta and O—H⋯O hydrogen bonds.




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Chlorido­[(1,2,5,6-η)-cyclo­octa-1,5-diene](1-ethyl-4-isobutyl-1,2,4-triazol-5-yl­idene)rhodium(I)

A new neutral triazole-based N-heterocyclic carbene rhodium(I) complex [RhCl(C8H12)(C8H15N3)], has been synthesized and structurally characterized. The complex crystallizes with two mol­ecules in the asymmetric unit. The central rhodium(I) atom has a distorted square-planar coordination environment, formed by a cyclo­octa-1,5-diene (COD) ligand, an N-heterocyclic carbene (NHC) ligand, and a chlorido ligand. The bond lengths are unexceptional. A weak inter­molecular non-standard hydrogen-bonding inter­action exists between the chlorido and NHC ligands.




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(η6-Benzene)­chlorido­[(S)-2-(4-isopropyl-4,5-di­hydro­oxazol-2-yl)phenolato]ruthenium(II)

The title compound, [Ru(C12H14NO2)Cl(η6-C6H6)], exhibits a half-sandwich tripod stand structure and crystallizes in the ortho­rhom­bic space group P212121. The arene group is η6 π-coordinated to the Ru atom with a centroid-to-metal distance of 1.6590 (5) Å, with the (S)-2-(4-isopropyl-4,5-di­hydro­oxazol-2-yl)phenolate chelate ligand forming a bite angle of 86.88 (19)° through its N and phenolate O atoms. The pseudo-octa­hedral geometry assumed by the complex is completed by a chloride ligand. The coordination of the optically pure bidentate ligand induces metal centered chirality onto the complex with a Flack parameter of −0.056.




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Diisobutyl­ammonium tri­phenyl(2-thiolato­acetato-κ2O,S)stannate(IV)

Crystals of the title salt, (C8H20N)[Sn(C6H5)3(C2H2O2S)], comprise diisobutyl­ammonium cations and mercapto­acetato­tri­phenyl­stannate(IV) anions. The bidentate binding mode of the mercapto­acetate ligand gives rise to a five-coordinated, ionic tri­phenyl­tin complex with a distorted cis-trigonal–bipyramidal geometry around the tin atom. In the crystal, charge-assisted ammonium-N—H⋯O(carboxyl­ate) hydrogen-bonding connects two cations and two anions into a four-ion aggregate. Two positions were resolved for one of the phenyl rings with the major component having a site occupancy factor of 0.60 (3).




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[(1,2,5,6-η)-Cyclo­octa-1,5-diene](1-ethyl-4-isobutyl-1,2,4-triazol-5-yl­idene)(tri­phenyl­phosphane)rhodium(I) tetra­fluorido­borate

A new, cationic N-heterocyclic carbene RhI complex with a tetra­fluorido­borate counter-anion, [Rh(C8H12)(C8H15N3)(C18H15P)]BF4, has been synthesized and structurally characterized. There are two independent ion pairs in the asymmetric unit. Each complex cation exhibits a distorted square-planar conformation around the RhI atom. Bond lengths and bond angles are as expected for an Rh–NHC complex. There are several close, non-standard C—H⋯F hydrogen-bonding inter­actions between the ions. One of the tetra­fluorido­borate anions shows statistical disorder of the F atoms.




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Redetermined structure of 4-(benz­yloxy)benzoic acid

In the title compound, C14H14O3, the dihedral angle between the aromatic rings is 39.76 (9)°. In the crystal, the mol­ecules associate to form centrosymmetric acid–acid dimers linked by pairwise O—H⋯O hydrogen bonds. The precision of the geometric parameters in the present single-crystal study is about an order of magnitude better than the previous powder diffraction study [Chattopadhyay et al. (2013). CrystEngComm, 15, 1077–1085].




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Di­chloridotetra­kis­(3-meth­oxy­aniline)nickel(II)

The reaction of nickel(II) chloride with 3-meth­oxy­aniline yielded di­chlorido­tetra­kis­(3-meth­oxy­aniline)nickel(II), [NiCl2(C7H9NO)4], as yellow crystals. The NiII ion is pseudo-octa­hedral with the chloride ions trans to each other. The four 3-meth­oxy­aniline ligands differ primarily due to different conformations about the Ni—N bond, which also affect the hydrogen bonding. Inter­molecular N—H⋯ Cl hydrogen bonds and short Cl⋯Cl contacts between mol­ecules link them into chains parallel to the b axis.




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Bis[μ-3-(pyridin-2-yl)pyrazolato]bis­[acetato­(3,5-dimethyl-1H-pyrazole)­nickel(II)]

The title compound, [Ni2(C8H6N3)2(C2H3O2)2(C5H8N2)2] or [Ni(μ-OOCCH3)(2-PyPz)(Me2PzH)]2 (1) [2-PyPz = 3-(pyridin-2-yl) pyrazole; Me2PzH = 3,5-dimethyl pyrazole] was synthesized from Ni(OOCCH3)2·4H2O, 2-PyPzH, Me2PzH and tri­ethyl­amine as a base. Compound 1 {[Ni2(C30H34N10Ni2O4)]} at 100 K has monoclinic (P21/n) symmetry and the mol­ecules have crystallographic inversion symmetry. Mol­ecules of 1 comprise an almost planar dinuclear NiII core with an N4O2 coordination environment. The equatorial plane consists of N3,O coordination derived from one of the bidentate acetate O atoms and three of the N atoms of the chelating 2-PyPz ligand while the axial positions are occupied by neutral Me2PzH and the second O atom of the acetate unit. The Ni atoms are bridged by the nitro­gen atom of a deprotonated 2-PyPz ligand. Compound 1 exhibits various inter- and intra­molecular C—H⋯O and N—H⋯O hydrogen bonds.




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Bis(2-carb­oxy­quinolinium) hexa­chlorido­stan­nate(IV) dihydrate

In the hydrated title salt, (C10H8NO2)2[SnCl6]·2H2O, the tin(IV) atom is located about a center of inversion. In the crystal structure, the organic cation, the octa­hedral inorganic anion and the water mol­ecule of crystallization inter­act through O—H⋯O, N—H⋯O and O—H⋯Cl hydrogen bonds, supplemented by weak π–π stacking between neighboring cations, and C—Cl⋯π inter­actions.




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Pyridinium tosyl­ate

The title compound (systematic name: pyridinium 4-methyl­benzene­sulfonate), C5H6N+·C7H7O3S−, is the pyridinium salt of para-toluene­sulfonic acid. In the crystal, classical N—H⋯O hydrogen bonds as well as C—H⋯O contacts connect the cationic and anionic entities into sheets lying parallel to the ab plane.




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Poly[tris­(2-amino­butan-1-ol)copper(II) [hexa­kis-μ2-cyanido-κ12C:N-tetra­copper(I)] bis­(2-amino­butan-1-olato)aqua­copper(II) monohydrate]

The title structure, {[Cu(C4H11NO)3][Cu4(CN)6]·[Cu(C4H10NO)2(H2O)]·H2O}n, is made up of diperiodic honeycomb CuICN networks built from [Cu4(CN)6]2− units, together with two independent CuII complexes: six-coord­inate [Cu(CH3CH2CH(NH2)CH2OH)3]2+ cations, and five-coordinate [Cu(CH3CH2CH(NH2)CH2O)2·H2O] neutral species. The two CuII complexes are not covalently bonded to the CuICN networks. Strong O—H⋯O hydrogen bonds link the CuII complexes into pairs and the pairs are hydrogen bonded into chains along the crystallographic b axis via the hydrate water mol­ecule. In addition, O—H⋯(CN) and N—H⋯(CN) hydrogen bonds link the cations to the CuCN network. In the honeycomb polymeric moiety, all bridging cyanido ligands are disordered over two orientations, head-to-tail and tail-to-head, with occupancies for C and N atoms varying for each CN group.




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μ-Chlorido-bis­{[1-benzyl-3-(2,4,6-tri­methyl­phen­yl)imidazol-2-yl­idene-κC]silver(I)} chloride 1,2-di­chloro­ethane hemisolvate

The title compound, [Ag2(C19H20N2)4]Cl·0.5C2H4Cl2, can be readily generated by treatment of (1-benzyl-3-(2,4,6-tri­methyl­phen­yl)imidazolium chloride with sodium bis­(tri­methyl­sil­yl)amide followed by silver chloride. The mol­ecular structure of the compound was confirmed using NMR spectroscopy and single-crystal X-ray diffraction analysis. The crystal structure of the title compound at 110 K has monoclinic (P21/c) symmetry. The represented silver compound is of inter­est with respect to anti­bacterial properties and the structure displays a series of weak inter­molecular hydrogen-bonding inter­actions with the chloride counter-anion.




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Bis[2-(isoquinolin-1-yl)phenyl-κ2N,C1](2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline-κ2N,N')iridium(III) hexa­fluorido­phosphate methanol monosolvate

The title compound, [Ir(C15H10N)2(C19H12N4)]PF6·CH3OH, crystallizes in the C2/c space group with one monocationic iridium complex, one hexa­fluorido­phosphate anion, and one methanol solvent mol­ecule of crystallization in the asymmetric unit, all in general positions. The anion and solvent are linked to the iridium complex cation via hydrogen bonding. All bond lengths and angles fall into expected ranges compared to similar compounds.




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Redetermined structure of methyl 3-{4,4-di­fluoro-2-[2-(methoxy­car­bon­yl)­ethyl]-1,3,5,7-tetra­methyl-4-bora-3a,4a-di­aza-s-in­da­cen-6-yl}pro­pion­ate

In the title compound, C21H27BF2N2O4, a highly fluorescent boron–dipyrromethene dye, the methyl­propionate moieties have different conformations. In the crystal, weak C—H⋯F and C—H⋯O inter­actions link the mol­ecules. Some optical properties are presented.




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(1R,2S,4aR,6S,8R,8aS)-1-(3-Hy­droxy­propano­yl)-1,3,6,8-tetra­methyl-1,2,4a,5,6,7,8,8a-octa­hydronaphthalene-2-carb­oxy­lic acid

The mol­ecular structure of C18H28O4, (+)-diplodiatoxin, is described, whereby the absolute configuration of the structure of diplodiatoxin has been confirmed by single-crystal X-ray diffraction. Diplodiatoxin crystallizes in the chiral P43212 space group with one mol­ecule in the asymmetric unit.




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Δ-Bis[(S)-2-(4-isopropyl-4,5-di­hydro­oxazol-2-yl)phenolato-κ2N,O1](1,10-phenanthroline-κ2N,N')ruthenium(III) hexa­fluorido­phosphate

The title compound, [Ru(C12H14NO2)2(C12H8N2)]PF6 crystallizes in the tetra­gonal Sohnke space group P41212. The two bidentate chiral salicyloxazoline ligands and the phenanthroline co-ligand coordinate to the central RuIII atom through N,O and N,N atom pairs to form bite angles of 89.76 (15) and 79.0 (2)°, respectively. The octa­hedral coordination of the bidentate ligands leads to a propeller-like shape, which induces metal-centered chirality onto the complex, with a right-handed (Δ) absolute configuration [the Flack parameter value is −0.003 (14)]. Both the complex cation and the disordered PF6− counter-anion are located on twofold rotation axes. Apart from Coulombic forces, the crystal cohesion is ensured by non-classical C—H⋯O and C—H⋯F inter­actions.




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Di-μ-adipato-κ4O1,O1':O6,O6'-bis­[(2,2'-di­pyridyl­amine-κ2N,N')zinc(II)] trihydrate

The title compound, [Zn2(C6H8O4)2(C10H9N3)2]·3H2O or {Zn2[(C5H4N)2NH]2[μ-(CH2)4(COO)2]2}·3H2O, was separ­ated from the solvothermal reaction of zinc(II) sulfate hepta­hydrate, 2,2'-di­pyridyl­amine and sodium adipate. The dinuclear metal complex has a centrosymmetric structure, with the ZnII atom adopting a highly distorted octa­hedral coordination sphere composed of four oxygen atoms from bridging adipato ligands and two pyridine nitro­gen atoms. In the crystal, the title compound aggregates into a tri-periodic supra­molecular structure through inter­molecular hydrogen-bonding networks of the form O—H⋯O and N—H⋯O.




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[(1,2,5,6-η)-Cyclo­octa-1,5-diene](1-ethyl-4-iso­butyl-1,2,4-triazol-5-yl­idene)(tri­phenyl­phosphane)iridium(I) tetra­fluorido­borate di­chloro­methane hemisolvate

A new triazole-based N-heterocyclic carbene IrI cationic complex with a tetra­fluorido­borate counter-anion and hemi-solvating di­chloro­methane, [Ir(C8H12)(C8H15N3)(C18H15P)]BF4·0.5CH2Cl2, has been synthesized and structurally characterized. There are two independent ion pairs in the asymmetric unit and one di­chloro­methane solvent mol­ecule per two ion pairs. The cationic complex exhibits a distorted square-planar conformation around the IrI atom, formed by a bidentate cyclo­octa-1,5,diene (COD) ligand, a tri­phenyl­phosphane ligand, and an N-heterocyclic carbene (NHC). There are several close non-standard H⋯F hydrogen-bonding inter­actions that orient the tetra­fluorido­borate anions with respect to the IrI complex mol­ecules. The complex shows promising catalytic activity in transfer hydrogenation reactions. The structure was refined as a non-merohedral twin, and one of the COD mol­ecules is statistically disordered.




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(Z)-N-(2,6-Diiso­propyl­phen­yl)-1-[(2-meth­oxyphen­yl)amino]­methanimine oxide

The mol­ecular structure of the title compound, C20H26N2O2 reveals non-co-planarity between the central formamidine backbone and each of the outer meth­oxy- and i-propyl- substituted benzene rings with dihedral angles of 7.88 (15) and 81.17 (15)°, respectively, indicating significant twists in the mol­ecule. In the crystal, inter­molecular C—H⋯O inter­actions, forming an R34(30) graph set, occur within a two-dimensional layer that extends along the ac plane.




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(Z)-N-(2,6-Di­methyl­phen­yl)-1-[(2-meth­oxy­phen­yl)amino]­methanimine oxide methanol monosolvate

In the title solvate, C16H18N2O2·CH4O, the dihedral angles between the formamidine backbone and the pendant 2-meth­oxy­phenyl and 2,6-di­methyl­phenyl groups are 14.84 (11) and 81.61 (12)°, respectively. In the crystal, the components are linked by C—H⋯O, O—H⋯O and C—H⋯ π hydrogen bonds, generating a supra­molecular chain that extends along the crystallographic a-axis direction.




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meso-5,15-Bis[3-(iso­propyl­idenegalacto­pyran­oxy)phen­yl]-10,20-bis­(4-methyl­phen­yl)porphyrin

The crystal structure of a glycosyl­ated porphyrin (P_Gal2) system, C70H70N4O12, where two iso­propyl­idene protected galactose moieties are attached to the meso position of a substituted tetra­aryl porphyrin is reported. This structure reveals that the parent porphyrin is planar, with the galactose moieties positioned above and below the porphyrin macrocycle. This orientation likely prevents porphyrin–porphyrin H-type aggregation, potentially enhancing its efficiency as a photosensitizer in photodynamic therapy. Notable non-bonding C—H⋯O and C—H⋯π inter­actions among adjacent P_Gal2 systems are observed in this crystal network. Additionally, the tolyl groups of each porphyrin can engage in π–π inter­actions with the delocalized π-systems of neighboring porphyrins.




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Tris(4-chloro­phen­yl) phosphate

The title compound, C18H12Cl3O4P, is the symmetric phosphate derived from para-chloro­phenol and phospho­ric acid. Two of the three aromatic moieties adopt syn-orientation towards the P=O bond while the last chloro­phenol ring is pointing away from this bond. In the extended structure, C—H⋯O bonds connect the individual mol­ecules into sheets lying perpendicular to the crystallographic b axis.




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Structural insights into 1,4-bis­(neopent­yloxy)pillar[5]arene and the pyridine host–guest system

The crystal structure of 1,4-bis­(neopent­yloxy)pillar[5]arene, C95H140N2O10 (TbuP), featuring two encapsulated pyridine mol­ecules, reveals significant host–guest inter­actions. Inter­estingly, the pyridine guests are positioned near the neopent­yloxy substituents instead of the electron-rich aromatic core of the pillar[5]arene. This spatial arrangement suggests a preference for the pyridine mol­ecules to engage with the aliphatic regions of the host. Detailed analysis of the structural characteristics of this host–guest system (TbuP·2Py), as well as its packing pattern within the crystal network, is presented and discussed.




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α-d-2'-De­oxy­adenosine, an irradiation product of canonical DNA and a com­ponent of anomeric nucleic acids: crystal structure, packing and Hirshfeld surface analysis

α-d-2'-De­oxy­ribonucleosides are products of the γ-irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α-d-2'-de­oxy­adenosine (α-dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α-dA forms two conformers in the asymmetric unit which are connected by hydro­gen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydro­gen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α-nucleosides. The sugar conformation of both conformers is C2'-endo, and the 5'-hydroxyl groups are in a +sc orientation, probably due to the hydro­gen bonds formed by the conformers. The formation of the supra­molecular assembly of α-dA is controlled by hydro­gen bonding and stacking inter­actions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydro­gen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydro­gen bonds involving the sugar moieties to form a sheet. A com­parison of the solid-state structures of the anomeric 2'-de­oxy­adenosines revealed significant differences of their conformational parameters.




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Crystal structure and analytical profile of 1,2-di­phenyl-2-pyrrolidin-1-yl­ethanone hydro­chloride or `α-D2PV': a synthetic cathinone seized by law enforcement, along with its diluent sugar, myo-inositol

A confiscated package of street drugs was characterized by the usual mass spectral (MS) and FT–IR analyses. The confiscated powder material was highly crystalline and was found to consist of two very different species, accidentally of sizes convenient for X-ray diffraction. Thus, one each was selected and redundant com­plete sets of data were collected at 100 K using Cu Kα radiation. The selected crystals contained: (a) 1,2-diphenyl-2-(pyrrolidin-1-yl)ethanone hy­dro­chloride hemihydrate or 1-(2-oxo-1,2-di­phenyl­eth­yl)pyrrolidin-1-ium chloride hemihydrate, C18H20NO+·Cl−·0.5H2O, (I), a synthetic cathinone called `α-D2PV', and (b) the sugar myo-inositol, C6H12O6, (II), probably the only instance in which the drug and its diluent have been fully characterized from a single confiscated sample. Moreover, the structural details of both are rather attractive showing: (i) inter­esting hydrogen bonding observed in pairwise inter­actions by the drug mol­ecules, mediated by the chloride counter-anions and the waters of crystallization, and (ii) π–π inter­actions in the case of the phenyl rings of the drug which are of two different types, namely, π–π stacking and edge-to-π. Finally, the inositol crystallizes with Z' = 2 and the resulting diastereoisomers were examined by overlay techniques.




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Using synchrotron high-resolution powder X-ray diffraction for the structure determination of a new cocrystal formed by two active principle ingredients

The crystal structure of a new 1:1 cocrystal of carbamazepine and S-naproxen (C15H12N2O·C14H14O3) was solved from powder X-ray diffraction (PXRD). The PXRD pattern was measured at the high-resolution beamline CRISTAL at synchrotron SOLEIL (France). The structure was solved using Monte Carlo simulated annealing, then refined with Rietveld refinement. The positions of the H atoms were obtained from density functional theory (DFT) ground-state calculations. The symmetry is ortho­rhom­bic with the space group P212121 (No. 19) and the following lattice parameters: a = 33.5486 (9), b = 26.4223 (6), c = 5.3651 (10) Å and V = 4755.83 (19) Å3.




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Isostructural behaviour in ammonium and potassium salt forms of sulfonated azo dyes

The structures of five ammonium salt forms of mono­sulfonated azo dyes, derivatives of 4-(2-phenyldiazen-1-yl)benzenesulfonate, with the general formula [NH4][O3S(C6H4)NN(C6H3)RR']·XH2O [R = OH, NH2 or N(C2H4OH)2; R' = H or OH] are presented. All form simple layered structures with alternating hydro­phobic (organic) and hydro­philic (cation, solvent and polar groups) layers. To assess for isostructural behaviour of the ammonium cation with M+ ions, the packing of these structures is compared with literature examples. To aid this comparison, the corresponding structures of four potassium salt forms of the mono­sulfonated azo dyes are also presented herein. Of the five ammonium salts it is found that three have isostructural equivalents. In two cases this equivalent is a potassium salt form and in one case it is a rubidium salt form. The isostructurality of ion packing and of unit-cell symmetry and dimensions tolerates cases where the ammonium ions form somewhat different inter­action types with coformer species than do the potassium or rubidium ions. No sodium salt forms are found to be isostructural with any ammonium equivalent. However, similarities in the anion packing within a single hydro­phobic layer are found for a group that consists of the ammonium and rubidium salt forms of one azo anion species and the sodium and silver salt forms of a different azo species.




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Structure and absolute configuration of natural fungal product beauveriolide I, isolated from Cordyceps javanica, determined by 3D electron diffraction

Beauveriolides, including the main beauveriolide I {systematic name: (3R,6S,9S,13S)-9-benzyl-13-[(2S)-hexan-2-yl]-6-methyl-3-(2-methyl­prop­yl)-1-oxa-4,7,10-tri­aza­cyclo­tridecane-2,5,8,11-tetrone, C27H41N3O5}, are a series of cyclo­depsipeptides that have shown promising results in the treatment of Alzheimer's disease and in the prevention of foam cell formation in atherosclerosis. Their crystal structure studies have been difficult due to their tiny crystal size and fibre-like morphology, until now. Recent developments in 3D electron diffraction methodology have made it possible to accurately study the crystal structures of submicron crystals by overcoming the problems of beam sensitivity and dynamical scattering. In this study, the absolute structure of beauveriolide I was determined by 3D electron diffraction. The cyclo­dep­si­peptide crystallizes in the space group I2 with lattice parameters a = 40.2744 (4), b = 5.0976 (5), c = 27.698 (4) Å and β = 105.729 (6)°. After dynamical refinement, its absolute structure was determined by comparing the R factors and calculating the z-scores of the two possible enanti­omorphs of beauveriolide I.




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Synthesis, crystal structure and in-silico evaluation of aryl­sul­fon­amide Schiff bases for potential activity against colon cancer

This report presents a comprehensive investigation into the synthesis and characterization of Schiff base com­pounds derived from benzene­sul­fon­amide. The synthesis process, involved the reaction between N-cyclo­amino-2-sulf­anil­amide and various substituted o-salicyl­aldehydes, resulted in a set of com­pounds that were subjected to rigorous characterization using advanced spectral techniques, including 1H NMR, 13C NMR and FT–IR spectroscopy, and single-crystal X-ray diffraction. Furthermore, an in-depth assessment of the synthesized com­pounds was conducted through Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) analysis, in conjunction with docking studies, to elucidate their pharmacokinetic profiles and potential. Impressively, the ADMET analysis showcased encouraging drug-likeness properties of the newly synthesized Schiff bases. These computational findings were substanti­ated by mol­ecular properties derived from density functional theory (DFT) calculations using the B3LYP/6-31G* method within the Jaguar Module of Schrödinger 2023-2 from Maestro (Schrodinger LLC, New York, USA). The ex­plor­ation of frontier mol­ecular orbitals (HOMO and LUMO) enabled the computation of global reactivity descriptors (GRDs), encompassing charge separation (Egap) and global softness (S). Notably, within this analysis, one Schiff base, namely, 4-bromo-2-{N-[2-(pyr­rol­idine-1-sul­fonyl)phenyl]car­box­imid­oyl}phenol, 20, em­erged with the smallest charge separation (ΔEgap = 3.5780 eV), signifying heightened potential for biological properties. Conversely, 4-bromo-2-{N-[2-(piper­idine-1-sul­fonyl)phenyl]car­box­imid­oyl}phenol, 17, exhibited the largest charge separation (ΔEgap = 4.9242 eV), implying a relatively lower propensity for biological activity. Moreover, the synthesized Schiff bases displayed re­marke­able inhibition of tankyrase poly(ADP-ribose) polymerase enzymes, integral in colon cancer, surpassing the efficacy of a standard drug used for the same purpose. Additionally, their bioavailability scores aligned closely with established medications such as trifluridine and 5-fluoro­uracil. The ex­plor­ation of mol­ecular electrostatic potential through colour mapping delved into the electronic behaviour and reactivity tendencies intrinsic to this diverse range of mol­ecules.




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Absolute structure determination of Berkecoumarin by X-ray and electron diffraction

X-ray and electron diffraction methods independently identify the S-enanti­omer of Berkecoumarin [systematic name: (S)-8-hy­droxy-3-(2-hy­droxy­prop­yl)-6-meth­oxy-2H-chromen-2-one]. Isolated from Berkeley Pit Lake Penicillium sp., Berkecoumarin is a natural product with a light-atom com­position (C13H14O5) that challenges in-house absolute structure determination by anomalous scattering. This study further demonstrates the utility of dynamical refinement of electron-diffraction data for absolute structure determination.




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Borotropic shifting of the hydro­tris­[3-(2-furyl)pyrazol-1-yl]borate ligand in high-coordinate lan­tha­nide com­plexes

The coordination of hydro­tris­[3-(2-furyl)pyrazol-1-yl]borate (Tp2-Fu, C21H16BN6O3) to lan­tha­nide(III) ions is achieved for the first time with the com­plex [Ln(Tp2-Fu)2](BPh4)·xCH2Cl2 (1-Ln has Ln = Ce and x = 2; 1-Dy has Ln = Dy and x = 1). This was accom­plished via both hydrous (Ln = Ce) and anhydrous methods (Ln = Dy). When isolating the dysprosium analogue, the filtrate produced a second crop of crystals which were revealed to be the 1,2-borotropic-shifted product [Dy(κ4-Tp2-Fu)(κ5-Tp2-Fu*)](BPh4) (2) {Tp2-Fu* = hydro­bis­[3-(2-furyl)pyrazol-1-yl][5-(2-furyl)pyrazol-1-yl]borate}. We con­clude that the pres­ence of a strong Lewis acid and a sterically crowded coordination environment are contributing factors for the 1,2-borotropic shifting of scorpionate ligands in conjunction with the size of the conical angle with the scorpionate ligand.




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Relationship between synthesis method–crystal structure–melting properties in co­crystals: the case of caffeine–citric acid

The influence of the crystal synthesis method on the crystallographic structure of caffeine–citric acid co­crystals was analyzed thanks to the synthesis of a new polymorphic form of the cocrystal. In order to com­pare the new form to the already known forms, the crystal structure of the new cocrystal (C8H10N4O2·C6H8O7) was solved by powder X-ray diffraction thanks to synchrotron experiments. The structure determination was performed using `GALLOP', a recently developed hybrid approach based on a local optimization with a particle swarm optimizer, particularly powerful when applied to the structure resolution of materials of pharmaceutical inter­est, com­pared to classical Monte-Carlo simulated annealing. The final structure was obtained through Rietveld refinement, and first-principles density functional theory (DFT) calculations were used to locate the H atoms. The symmetry is triclinic with the space group Poverline{1} and contains one mol­ecule of caffeine and one mol­ecule of citric acid per asymmetric unit. The crystallographic structure of this cocrystal involves different hydrogen-bond associations com­pared to the already known structures. The analysis of these hydrogen bonds indicates that the cocrystal obtained here is less stable than the co­crystals already identified in the literature. This analysis is confirmed by the determination of the melting point of this cocrystal, which is lower than that of the previously known co­crystals.




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Crystal structures, electron spin resonance, and thermogravimetric analysis of three mixed-valence copper cyanide polymers

The crystal structures of three mixed-valence copper cyanide alkanolamine polymers are presented, together with thermogravimetric analysis (TGA) and electron spin resonance (ESR) data. In all three structures, a CuII moiety on a crystallographic center of symmetry is coordinated by two alkanolamines and links two CuICN chains via cyanide bridging groups to form diperiodic sheets. The sheets are linked together by cuprophilic CuI–CuI inter­actions to form a three-dimensional network. In poly[bis­(μ-3-amino­propano­lato)tetra-μ-cyan­ido-dicopper(I)dicopper(II)], [Cu4(CN)4(C3H8NO)2]n, 1, propano­lamine bases have lost their hydroxyl H atoms and coordinate as chelates to two CuII atoms to form a dimeric CuII moiety bridged by the O atoms of the bases with CuII atoms in square-planar coordination. The ESR spectrum is very broad, indicating exchange between the two CuII centers. In poly[bis­(2-amino­pro­pan­ol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(C3H9NO)2]n, 2, and poly[bis­(2-amino­ethanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(CH7NO)2]n, 3, a single CuII atom links the CuICN chains together via CN bridges. The chelating alkanolamines are not ionized, and the OH groups form rather long bonds in the axial positions of the octa­hedrally coordinated CuII atoms. The coordination geometries of CuII in 2 and 3 are almost identical, except that the Cu—O distances are longer in 2 than in 3, which may explain their somewhat different ESR spectra. Thermal decom­position in 2 and 3, but not in 1, begins with the loss of HCN(g), and this can be correlated with the presence of OH protons on the ligands in 2 and 3, which are not present in 1.




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Mol­ecular structure and selective theophylline com­plexation by conformational change of diethyl N,N'-(1,3-phenyl­ene)dicarbamate

The receptor ability of diethyl N,N'-(1,3-phenyl­ene)dicarbamate (1) to form host–guest com­plexes with theophylline (TEO) and caffeine (CAF) by mechanochemistry was evaluated. The formation of the 1–TEO com­plex (C12H16N2O4·C7H8N4O2) was preferred and involves the conformational change of one of the ethyl carbamate groups of 1 from the endo conformation to the exo conformation to allow the formation of inter­molecular inter­actions. The formation of an N—H⋯O=C hydrogen bond between 1 and TEO triggers the conformational change of 1. CAF mol­ecules are unable to form an N—H⋯O=C hydrogen bond with 1, making the conformational change and, therefore, the formation of the com­plex impossible. Conformational change and selective binding were monitored by IR spectroscopy, solid-state 13C nuclear magnetic resonance and single-crystal X-ray diffraction. The 1–TEO com­plex was characterized by IR spectroscopy, solid-state 13C nuclear magnetic resonance, powder X-ray diffraction and single-crystal X-ray diffraction.




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Rebuttal to the article Pathological crystal structures

A section in the Acta Crystallographica Section C article by Raymond & Girolami [Acta Cryst. (2023), C79, 445–455] stated that the product of the reaction of [(Cp*Rh)2(μ-OH)3]+ (Cp* is 1,2,3,4,5-penta­methyl­cyclo­penta­diene) with 1-methyl­thymine (1-MT) at pH 10 and 60 °C, to synthesize the anionic com­ponent [RhI(η1-N3-1-MT)2]−, was not an RhI com­plex, but rather an AgI com­plex, due to the use of silver triflate (AgOTf) to remove Cl− from [Cp*RhCl2]2 to synthesize [Cp*Rh(H2O)3](OTf)2, a water-soluble crystalline com­plex. We will clearly show that this premise, as stated, is invalid, while the authors have simply avoided several important facts, including that Cp*OH, a reductive elimination product, at pH 10 and 60 °C, was unequivocally identified, thus leading to the RhI anionic com­ponent [RhI(η1-N3-1-MT)2]−. More importantly, AgOH, from the reaction of NaOH at pH 10 with any potentially remaining AgOTf, after the AgCl was filtered off, would be insoluble in water. Furthermore, a control experiment with the inorganic com­plex Rh(OH)3, reacting with 1-methyl­thymine at pH 10, provided no product, and this bodes well for a similar fate with AgOTf and 1-methyl­thymine, i.e. at pH 10, AgOTf would again be converted to the water-insoluble AgOH; therefore, no reaction would occur! Finally, a 1H NMR spectroscopy experiment was carried out with synthesized and crystallized [Cp*Rh(H2O)3](OTf)2 in D2O at various pD values; at pD 8.65 no reaction took place, while at pD 13.6, and at 60 °C for 2 h, a reductive elimination reaction caused the precipitation of Cp*OH. The subsequent 1H NMR spectrum clearly demonstrated, in the absence of any AgI com­plexes, that the solution structure and the X-ray crystals in D2O were similar. A postulated mechanism for this novel anionic com­ponent structure, as published previously [Smith et al. (2014). Organometallics, 33, 2389–2404], will be presented, along with the experimental data, to insure the credibility of our results. We will also answer the comments in the response of Drs Raymond and Girolami to this rebuttal.




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Response to the rebuttal of the article Pathological crystal structures

We stand fully behind our earlier suggestion [Raymond & Girolami (2023). Acta Cryst. C79, 445–455] that the claim by Fish and co-workers [Chen et al. (1995). J. Am. Chem. Soc. 117, 9097–9098; Smith et al. (2014). Organometallics, 33, 2389–2404] of a linear two-coordinate rhodium(I) species is incorrect, and that the putative rhodium atom is in fact silver.




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Applying 3D ED/MicroED workflows toward the next frontiers

We report on the latest advancements in Microcrystal Electron Diffraction (3D ED/MicroED), as discussed during a symposium at the National Center for CryoEM Access and Training housed at the New York Structural Biology Center. This snapshot describes cutting-edge developments in various facets of the field and identifies potential avenues for continued progress. Key sections discuss instrumentation access, research applications for small mol­ecules and biomacromolecules, data collection hardware and software, data reduction software, and finally reporting and validation. 3D ED/MicroED is still early in its wide adoption by the structural science community with ample opportunities for expansion, growth, and innovation.




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Formation of extended polyiodides at large cation templates

By studying the structures of (μ-1,4,10,13-tetra­thia-7,16-di­aza­cyclo­octa­deca­ne)bis[iodidopalladium(II)] diiodide penta­(diiodine), [Pd2I2(C12H26N2S4)](I)2·5I2 or [Pd2I2([18]aneN2S4)](I)2·(I2)5, and 4,7,13,16,21,24-hexa­oxa-1,10-diazo­niabi­cyclo­[8.8.8]hexa­cosane triiodide iodide hemi­penta­(diiodine) di­chloro­methane mono­solvate, C18H38N2O62+·I3−·I−·2.5I2·CH2Cl2 or [H2([2.2.2]cryptand)](I3)(I)(I2)2.5·CH2Cl2, we confirm the structural variety of extended polyiodides achievable upon changing the shape, charge and dimensions of the cation template, by altering the synthetic strategy adopted and/or the experimental conditions. Although it is still often difficult to characterize discrete [I2m+n]n− polyiodides higher than I3− on the basis of structural parameters, such as I—I bond distances, FT–Raman spectroscopy appears to identify them as aggregates of I2, I− and (symmetric or slightly asymmetric) I3− building blocks linked by I⋯I inter­actions of varying strengths. However, because FT–Raman spectroscopy carries no information about the topological features of extended polyiodides, the two techniques should therefore be applied in combination to enhance the analysis of this kind of compounds.




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Synthesis, characterization and structural analysis of com­plexes from 2,2':6',2''-terpyridine derivatives with transition metals

The synthesis and structural characterization of three families of coordination com­plexes synthesized from 4'-phenyl-2,2':6',2''-terpyridine (8, Ph-TPY), 4'-(4-chloro­phen­yl)-2,2':6',2''-terpyridine (9, ClPh-TPY) and 4'-(4-meth­oxy­phen­yl)-2,2':6',2''-terpyridine (10, MeOPh-TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The com­pounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of com­plexes with the general formula [M(R-TPY)2](ClO4)2 (where M = Co2+, Fe2+, Mn2+ and Ni2+, and R-TPY = Ph-TPY, ClPh-TPY and MeOPh-TPY). The general formula and structural and supra­molecular features were determinated by single-crystal X-ray diffraction for bis­(4'-phenyl-2,2':6',2''-terpyridine)­nickel(II) bis­(per­chlo­rate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph-TPY)2](ClO4)2, bis­[4'-(4-meth­oxy­phen­yl)-2,2':6',2''-terpyridine]­manganese(II) bis­(per­chlo­rate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh-TPY)2](ClO4)2, and bis­(4'-phenyl-2,2':6',2''-ter­py­ridine)­manganese(II) bis­(per­chlo­rate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph-TPY)2](ClO4)2. In all three cases, the com­plexes present distorted octa­hedral coordination polyhedra and the crystal packing is determined mainly by weak C—H⋯π inter­actions. All the com­pounds (except for the Ni derivatives, for which FT–IR, UV–Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT–IR, UV–Vis and NMR spectroscopy) and thermal (TGA–DSC, thermogravimetric analysis–differential scanning calorimetry) methods.




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Supra­molecular hy­dro­gen-bonded networks formed from copper(II) car­box­yl­ate dimers

The well-known copper car­box­yl­ate dimer, with four car­box­yl­ate ligands ex­ten­ding outwards towards the corners of a square, has been employed to generate a series of crystalline com­pounds. In particular, this work centres on the use of the 4-hy­droxy­benzoate anion (Hhba−) and its deprotonated phe­nol­ate form 4-oxidobenzoate (hba2−) to obtain complexes with the general formula [Cu2(Hhba)4–x(hba)xL2–y]x−, where L is an axial coligand (including solvent mol­ecules), x = 0, 1 or 2, and y = 0 or 1. In some cases, short hy­dro­gen bonds result in complexes which may be represented as [Cu2(Hhba)2(H0.5hba)2L2]−. The main focus of the investigation is on the formation of a variety of extended networks through hy­dro­gen bonding and, in some crystals, coordinate bonds when bridging coligands (L) are employed. Crystals of [Cu2(Hhba)4(di­ox­ane)2]·4(di­ox­ane) consist of the expected Cu dimer with the Hhba− anions forming hy­dro­gen bonds to 1,4-di­ox­ane mol­ecules which block network formation. In the case of crystals of com­position [Et4N][Cu2(Hhba)2(H0.5hba)2(CH3OH)(H2O)]·2(di­ox­ane), Li[Cu2(Hhba)2(H0.5hba)2(H2O)2]·3(di­ox­ane)·4H2O and [Cu2(Hhba)2(H0.5hba)2(H0.5DABCO)2]·3CH3OH (DABCO is 1,4-di­aza­bicyclo­[2.2.2]octa­ne), square-grid hy­dro­gen-bonded networks are generated in which the complex serves as one type of 4-con­necting node, whilst a second 4-con­necting node is a hy­dro­gen-bonding motif assembled from four phenol/phenolate groups. Another two-dimensional (2D) network based upon a related square-grid structure is formed in the case of [Et4N]2[Cu2(Hhba)2(hba)2(di­ox­ane)2][Cu2(Hhba)4(di­ox­ane)(H2O)]·CH3OH. In [Cu2(Hhba)4(H2O)2]·2(Et4NNO3), a square-grid structure is again apparent, but, in this case, a pair of nitrate anions, along with four phenolic groups and a pair of water mol­ecules, combine to form a second type of 4-con­necting node. When 1,8-bis­(di­methyl­amino)­naphthalene (bdn, `proton sponge') is used as a base, another square-grid network is generated, i.e. [Hbdn]2[Cu2(Hhba)2(hba)2(H2O)2]·3(di­ox­ane)·H2O, but with only the copper dimer complex serving as a 4-con­necting node. Complex three-dimensional networks are formed in [Cu2(Hhba)4(O-bipy)]·H2O and [Cu2(Hhba)4(O-bipy)2]·2(di­ox­ane), where the potentially bridging 4,4'-bi­pyridine N,N'-dioxide (O-bipy) ligand is employed. Rare cases of mixed car­box­yl­ate copper dimer complexes were obtained in the cases of [Cu2(Hhba)3(OAc)(di­ox­ane)]·3.5(di­ox­ane) and [Cu2(Hhba)2(OAc)2(DABCO)2]·10(di­ox­ane), with each structure possessing a 2D network structure. The final com­pound re­por­ted is a simple hy­dro­gen-bonded chain of com­position (H0.5DABCO)(H1.5hba), formed from the reaction of H2hba and DABCO.




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Using cocrystals as a tool to study non-crystallizing mol­ecules: crystal structure, Hirshfeld surface analysis and com­putational study of the 1:1 cocrystal of (E)-N-(3,4-di­fluoro­phen­yl)-1-(pyridin-4-yl)methanimine and acetic

Using a 1:1 cocrystal of (E)-N-(3,4-di­fluoro­phen­yl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π–π inter­actions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and com­putational studies, we reveal the mol­ecular arrangement within this co­crystal, demonstrating the presence of hydrogen bonding between the acetic acid mol­ecule and the pyridyl group, along with π–π inter­actions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π–π inter­actions without necessitating full halogenation of the aromatic ring.




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Crystal structure elucidation of a geminal and vicinal bis­(tri­fluoro­methane­sulfonate) ester

Geminal and vicinal bis­(tri­fluoro­methane­sulfonate) esters are highly reactive alkyl­ene synthons used as potent electrophiles in the macrocyclization of imid­azoles and the transformation of bypyridines to diquat derivatives via nucleophilic substitution reactions. Herein we report the crystal structures of methyl­ene (C3H2F6O6S2) and ethyl­ene bis­(tri­fluoro­methane­sulfonate) (C4H4F6O6S2), the first examples of a geminal and vicinal bis­(tri­fluoro­methane­sulfonate) ester characterized by single-crystal X-ray diffraction (SC-XRD). With melting points slightly below ambient temperature, both reported bis­(tri­fluoro­methane­sulfonate)s are air- and moisture-sensitive oils and were crys­tallized at 277 K to afford two-com­ponent non-merohedrally twinned crystals. The dominant inter­actions present in both com­pounds are non-classical C—H⋯O hydrogen bonds and inter­molecular C—F⋯F—C inter­actions between tri­fluoro­methyl groups. Mol­ecular electrostatic potential (MEP) cal­culations by DFT-D3 helped to qu­antify the polarity between O⋯H and F⋯F contacts to rationalize the self-sorting of both bis­(tri­fluoro­methane­sulfonate) esters in polar (non-fluorous) and non-polar (fluorous) domains within the crystal structure.