Hayden Library - TA418.9.N35 F87 2018

Actinobacillus pleuropneumoniae (App) is the etiological agent of acute porcine pneumonia and responsible for severe economic losses worldwide. The capsule polymer of App serotype 1 (App1) consists of [4)-GlcNAc-β(1,6)-Gal-α-1-(PO4-] repeating units that are O-acetylated at O-6 of the GlcNAc. It is a major virulence factor and was used in previous studies in the successful generation of an experimental glycoconjugate vaccine. However, the application of glycoconjugate vaccines in the animal health sector is limited, presumably because of the high costs associated with harvesting the polymer from pathogen culture. Consequently, here we exploited the capsule polymerase Cps1B of App1 as an in vitro synthesis tool and an alternative for capsule polymer provision. Cps1B consists of two catalytic domains, as well as a domain rich in tetratricopeptide repeats (TPRs). We compared the elongation mechanism of Cps1B with that of a ΔTPR truncation (Cps1B-ΔTPR). Interestingly, the product profiles displayed by Cps1B suggested processive elongation of the nascent polymer, whereas Cps1B-ΔTPR appeared to work in a more distributive manner. The dispersity of the synthesized products could be reduced by generating single-action transferases and immobilizing them on individual columns, separating the two catalytic activities. Furthermore, we identified the O-acetyltransferase Cps1D of App1 and used it to modify the polymers produced by Cps1B. Two-dimensional NMR analyses of the products revealed O-acetylation levels identical to those of polymer harvested from App1 culture supernatants. In conclusion, we have established a protocol for the pathogen-free in vitro synthesis of tailored, nature-identical App1 capsule polymers.

Multidrug resistance (MDR) in cancer arises from cross-resistance to structurally- and functionally-divergent chemotherapeutic drugs. In particular, MDR is characterized by increased expression and activity of ATP-binding cassette (ABC) superfamily transporters. Sphingolipids are substrates of ABC proteins in cell signaling, membrane biosynthesis, and inflammation, for example, and their products can favor cancer progression. Glucosylceramide (GlcCer) is a ubiquitous glycosphingolipid (GSL) generated by glucosylceramide synthase, a key regulatory enzyme encoded by the UDP-glucose ceramide glucosyltransferase (UGCG) gene. Stressed cells increase de novo biosynthesis of ceramides, which return to sub-toxic levels after UGCG mediates incorporation into GlcCer. Given that cancer cells seem to mobilize UGCG and have increased GSL content for ceramide clearance, which ultimately contributes to chemotherapy failure, here we investigated how inhibition of GSL biosynthesis affects the MDR phenotype of chronic myeloid leukemias. We found that MDR is associated with higher UGCG expression and with a complex GSL profile. UGCG inhibition with the ceramide analog d-threo-1-(3,4,-ethylenedioxy)phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (EtDO-P4) greatly reduced GSL and monosialotetrahexosylganglioside levels, and co-treatment with standard chemotherapeutics sensitized cells to mitochondrial membrane potential loss and apoptosis. ABC subfamily B member 1 (ABCB1) expression was reduced, and ABCC-mediated efflux activity was modulated by competition with nonglycosylated ceramides. Consistently, inhibition of ABCC-mediated transport reduced the efflux of exogenous C6-ceramide. Overall, UGCG inhibition impaired the malignant glycophenotype of MDR leukemias, which typically overcomes drug resistance through distinct mechanisms. This work sheds light on the involvement of GSL in chemotherapy failure, and its findings suggest that targeted GSL modulation could help manage MDR leukemias.

A focus on customer enablement across all Cadence sub-organizations has led to a cross-functional effort to identify opportunities to bring our customers to proficiency with our products and flows. Hence, Rapid Adoption Kits -- RAKs -- for Synthesis...(read more)

This note identifies key findings and policy messages on how small and medium- sized enterprises (SMEs) in Southeast Asia can enhance integration in global value chains (GVCs). The list of policy messages in this note is not intended to be exhaustive but rather to provide a set of concrete and actionable measures.

Developing countries are disproportionately affected by the rising trend of losses from climate-related extreme events. This paper uses case studies of Colombia and Senegal to examine how countries are using financial protection as part of their approaches to managing climate risks; it also identifies emerging priorities for development co-operation providers in supporting financial protection against climate risks.

Higher level vocational education and training (VET) programmes are facing rapid change and intensifying challenges. What type of training is needed to meet the needs of changing economies? How should the programmes be funded? How should they be linked to academic and university programmes?

The crystal structure of the c-type cytochrome NirC from Pseudomonas aeruginosa has been determined and reveals the simultaneous presence of monomers and 3D domain-swapped dimers in the same asymmetric unit.

Reduction of the heteroleptic metal carbonyl complex Mo(CO)3(η5-Cp)H with the metallic salt Cs5Bi4 in the presence of [2.2.2]crypt (= 4,7,13,16,21,24-hexa­oxa-1,10-di­aza­bicyclo­[8.8.8]hexa­cosa­ne) in liquid ammonia led to single crystals of bis­[(4,7,13,16,21,24-hexa­oxa-1,10-di­aza­bicyclo­[8.8.8]hexa­cosa­ne)caesium] penta­carbonyl­molybdate, [Cs(C18H36N2O6)]2[Mo(CO)5] or [Cs([2.2.2]crypt)]2[Mo(CO)5]. The twofold negatively charged anionic complex corresponds to the 18 valence electron rule. It consists of an Mo atom coordinated by five carbonyl ligands in a shape inter­mediate between trigonal–bipyramidal and square-pyramidal. The Mo—C distances range from 1.961 (3) to 2.017 (3) Å, and the C≡O distances from 1.164 (3) to 1.180 (4) Å.

The synthesis, spectroscopic data and crystal and mol­ecular structures of four 3-(3-phenyl­prop-1-ene-3-one-1-yl)thio­phene derivatives, namely 1-(4-hydroxy­phen­yl)-3-(thio­phen-3-yl)prop-1-en-3-one, C13H10O2S, (1), 1-(4-meth­oxy­phen­yl)-3-(thio­phen-3-yl)prop-1-en-3-one, C14H12O2S, (2), 1-(4-eth­oxy­phen­yl)-3-(thio­phen-3-yl)prop-1-en-3-one, C15H14O2S, (3), and 1-(4-­bromophen­yl)-3-(thio­phen-3-yl)prop-1-en-3-one, C13H9BrOS, (4), are described. The four chalcones have been synthesized by reaction of thio­phene-3-carbaldehyde with an aceto­phenone derivative in an absolute ethanol solution containing potassium hydroxide, and differ in the substituent at the para position of the phenyl ring: –OH for 1, –OCH3 for 2, –OCH2CH3 for 3 and –Br for 4. The thio­phene ring in 4 was found to be disordered over two orientations with occupancies 0.702 (4) and 0.298 (4). The configuration about the C=C bond is E. The thio­phene and phenyl rings are inclined by 4.73 (12) for 1, 12.36 (11) for 2, 17.44 (11) for 3 and 46.1 (6) and 48.6 (6)° for 4, indicating that the –OH derivative is almost planar and the –Br derivative deviates the most from planarity. However, the substituent has no real influence on the bond distances in the α,β-unsaturated carbonyl moiety. The mol­ecular packing of 1 features chain formation in the a-axis direction by O—H⋯O contacts. In the case of 2 and 3, the packing is characterized by dimer formation through C—H⋯O inter­actions. In addition, C—H⋯π(thio­phene) inter­actions in 2 and C—H⋯S(thio­phene) inter­actions in 3 contribute to the three-dimensional architecture. The presence of C—H⋯π(thio­phene) contacts in the crystal of 4 results in chain formation in the c-axis direction. The Hirshfeld surface analysis shows that for all four derivatives, the highest contribution to surface contacts arises from contacts in which H atoms are involved.

A new quinoline-based hydrazone, C16H12ClN3, was synthesized by a condensation reaction of 2-chloro-3-formyl­quinoline with phenyl­hydrazine. The quinoline ring system is essentially planar (r.m.s. deviation = 0.012 Å), and forms a dihedral angle of 8.46 (10)° with the phenyl ring. The mol­ecule adopts an E configuration with respect to the central C=N bond. In the crystal, mol­ecules are linked by a C—H⋯π-phenyl inter­action, forming zigzag chains propagating along the [10overline{3}] direction. The N—H hydrogen atom does not participate in hydrogen bonding but is directed towards the phenyl ring of an adjacent mol­ecule, so linking the chains via weak N—H⋯π inter­actions to form of a three-dimensional structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (35.5%), C⋯H/H⋯C (33.7%), Cl⋯H/H⋯Cl (12.3%), N⋯H/H⋯N (9.5%) contacts.

The asymmetric unit of the title compound, [Fe(NCS)2(C12H9NO)4], consists of an FeII ion that is located on a centre of inversion, as well as two 4-benzoyl­pyridine ligands and one thio­cyanate anion in general positions. The FeII ions are coordinated by two N-terminal-bonded thio­cyanate anions and four 4-benzoyl­pyridine ligands into discrete complexes with a slightly distorted octa­hedral geometry. These complexes are further linked by weak C—H⋯O hydrogen bonds into chains running along the c-axis direction. Upon heating, this complex loses half of the 4-benzoyl­pyridine ligands and transforms into a compound with the composition Fe(NCS)2(4-benzoyl­pyridine)2, that might be isotypic to the corresponding MnII compound and for which the structure is unknown.

Typical electroless copper baths (ECBs), which are used to chemically deposit copper on printed circuit boards, consist of an aqueous alkali hydroxide solution, a copper(II) salt, formaldehyde as reducing agent, an l-(+)-tartrate as complexing agent, and a 2,2'-bi­pyridine derivative as stabilizer. Actual speciation and reactivity are, however, largely unknown. Herein, we report on the synthesis and crystal structure of aqua-1κO-bis­(4,4'-dimeth­oxy-2,2'-bi­pyri­dine)-1κ2N,N';2κ2N,N'-[μ-(2R,3R)-2,3-dioxidosuccinato-1κ2O1,O2:2κ2O3,O4]dicopper(II) octa­hydrate, [Cu2(C12H12N2O2)2(C4H2O6)(H2O)]·8H2O, from an ECB mock-up. The title compound crystallizes in the Sohncke group P21 with one chiral dinuclear complex and eight mol­ecules of hydrate water in the asymmetric unit. The expected retention of the tartrato ligand's absolute configuration was confirmed via determination of the absolute structure. The complex mol­ecules exhibit an ansa-like structure with two planar, nearly parallel bi­pyridine ligands, each bound to a copper atom that is connected to the other by a bridging tartrato `handle'. The complex and water mol­ecules give rise to a layered supra­molecular structure dominated by alternating π stacks and hydrogen bonds. The understanding of structures ex situ is a first step on the way to prolonged stability and improved coating behavior of ECBs.

The hydro­thermal synthesis and crystal structure of the simple inorganic compound CaHPO3, which crystallizes in the chiral space group P43212, are reported. The structure is built up from distorted CaO7 capped trigonal prisms and HPO3 pseudo pyramids, which share corners and edges to generate a three-dimensional network.

From solutions of prehnitene and the ternary halides (SnCl)[MCl4] (M = Al, Ga) in chloro­benzene, the new cationic SnII–π-arene complexes catena-poly[[chlorido­aluminate(III)]-tri-μ-chlorido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­meth­yl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlorido­aluminate(III)]-μ-chlorido-4:1'κ2Cl], [Al2Sn2Cl10(C10H14)2]n, (1) and catena-poly[[chlorido­gallate(III)]-tri-μ-chlor­ido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlor­ido­gallate(III)]-μ-chlorido-4:1'κ2Cl], [Ga2Sn2Cl10(C10H14)2]n, (2), were isolated. In these first main-group metal–prehnitene complexes, the distorted η6 arene π-bonding to the tin atoms of the Sn2Cl22+ moieties in the centre of [{1,2,3,4-(CH3)4C6H2}2Sn2Cl2][MCl4]2 repeating units (site symmetry overline{1}) is characterized by: (i) a significant ring slippage of ca 0.4 Å indicated by the dispersion of Sn—C distances [1: 2.881 (2)–3.216 (2) Å; 2: 2.891 (3)–3.214 (3) Å]; (ii) the non-methyl-substituted arene C atoms positioned closest to the SnII central atom; (iii) a pronounced tilt of the plane of the arene ligand against the plane of the central (Sn2Cl2)2+ four-membered ring species [1: 15.59 (11)°, 2: 15.69 (9)°]; (iv) metal–arene bonding of medium strength as illustrated by application of the bond-valence method in an indirect manner, defining the π-arene bonding inter­action of the SnII central atoms as s(SnII—arene) = 2 − Σs(SnII—Cl), that gives s(SnII—arene) = 0.37 and 0.38 valence units for the aluminate and the gallate, respectively, indicating that comparatively strong main-group metal–arene bonding is present and in line with the expectation that [AlCl4]− is the slightly weaker coordinating anion as compared to [GaCl4]−.

The title compound, hexa­kis­(2-methyl-1H-imidazol-3-ium) hepta­molybdate 2-methyl-1H-imidazole disolvate dihydrate, (C4H7N2)6[Mo7O24]·2C4H6N2·2H2O, was prepared from 2-methyl­imidazole and ammonium hepta­molybdate tetra­hydrate in acid solution. The [Mo7O24]6− hepta­molybdate cluster anion is accompanied by six protonated (C4H7N2)+ 2-methyl­imidazolium cations, two neutral C4H6N2 2-methyl­imidazole mol­ecules and two water mol­ecules of crystallization. The cluster consists of seven distorted MoO6 octa­hedra sharing edges or vertices. In the crystal, the components are linked by N—H⋯N, N—H⋯O, O—H⋯O, N—H⋯(O,O) and O—H⋯(O,O) hydrogen bonds, generating a three-dimensional network. Weak C—H⋯O inter­actions consolidate the packing.

The asymmetric unit of the title compound, C12H22N+·CH3O3S−, consists of three (3,5-di­methyl­adamantan-1-yl)ammonium cations, C12H22N+, and three methane­sulfonate anions, CH3O3S−. In the crystal, the cations and anions associate via N—H⋯O hydrogen bonds into layers, parallel to the (001) plane, which include large supra­molecular hydrogen-bonded rings.

The synthesis and structure of 2,4,6,-tri­cyclo­butyl-1,3,5-trioxane, C15H24O3 1, is described. It was formed in 39% yield during the work-up of the Swern oxidation of cyclo­butyl­methanol and may serve as a stable precursor of the cyclo­butane carbaldehyde. The mol­ecule of 1 occupies a special position (3.m) located at the center of its 1,3,5-trioxane ring. The latter is in a chair conformation, with the symmetry-independent O and C atoms deviating by 0.651 (4) Å from the least-squares plane of the other atoms of the trioxane ring. All three cyclo­butane substituents, which have a butterfly conformation with an angle between the two planes of 25.7 (3)°, are in the cis conformation relative to the 1,3,5-trioxane ring. Inter­molecular C—H⋯O inter­actions between the 1,3,5-trioxane rings consolidate the crystal structure, forming stacks along the c-axis direction. The crystal studied was refined a as a racemic twin.

Two compounds, 1,3-diethyl-5-{(2E,4E)-6-[(E)-1,3,3-tri­methyl­indolin-2-yl­idene]hexa-2,4-dien-1-yl­idene}pyrimidine-2,4,6(1H,3H,5H)-trione or TMI, C25H29N3O3, and 1,3-diethyl-2-sulfanyl­idene-5-[2-(1,3,3-tri­methyl­indolin-2-yl­idene)ethyl­idene]di­hydro­pyrimidine-4,6(1H,5H)-dione or DTB, C21H25N3O2S, have been crystallized and studied. These compounds contain the same indole derivative donor group and differ in their acceptor groups (in TMI it contains oxygen in the para position, and in DTB sulfur) and the length of the π-bridge. In both materials, mol­ecules are packed in a herringbone manner with differences in the twist and fold angles. In both structures, the mol­ecules are connected by weak C—H⋯O and/or C—H⋯S bonds.

Imidazolium salts are common building blocks for functional materials and in the synthesis of N-heterocyclic carbene (NHC) as σ-donor ligands for stable metal complexes. The title salt, 1,3-bis­(4-hy­droxy­phen­yl)-1H-imidazol-3-ium chloride (IOH·Cl), C15H13N2O2+·Cl−, is a new imidazolium salt with a hy­droxy functionality. The synthesis of IOH·Cl was achieved in high yield via a two-step procedure involving a di­aza­butadiene precursor followed by ring closure using tri­methylchloro­silane and paraformaldehyde. The structure of IOH·Cl consists of a central planar imidazolium ring (r.m.s. deviation = 0.0015 Å), with out-of-plane phenolic side arms. The dihedral angles between the 4-hy­droxy­phenyl substituents and the imidazole ring are 55.27 (7) and 48.85 (11)°. In the crystal, O—H⋯Cl hydrogen bonds connect the distal hy­droxy groups and Cl− anions in adjacent asymmetric units, one related by inversion (−x + 1, −y + 1, −z + 1) and one by the n-glide (x − {1over 2}, −y + {1over 2}, z − {1over 2}), with donor–acceptor distances of 2.977 (2) and 3.0130 (18) Å, respectively. The phenolic rings are each π–π stacked with their respective inversion-related [(−x + 1, −y + 1, −z + 1) and (−x, −y + 1, −z + 1)] counterparts, with inter­planar distances of 3.560 (3) and 3.778 (3) Å. The only other noteworthy inter­molecular inter­action is an O⋯O (not hydrogen bonded) close contact of 2.999 (3) Å between crystallographically different hy­droxy O atoms on translationally adjacent mol­ecules (x + 1, y, x + 1).

Lapachol acetate [systematic name: 3-(3-methyl­but-2-en­yl)-1,4-dioxonaph­thalen-2-yl acetate], C17H16O4, was prepared using a modified high-yield procedure and its crystal structure is reported for the first time 80 years after its first synthesis. The full spectroscopic characterization of the mol­ecule is reported. The mol­ecular conformation shows little difference with other lapachol derivatives and lapachol itself. The packing is directed by inter­molecular π–π and C—H⋯O inter­actions, as described by Hirshfeld surface analysis. The former inter­actions make the largest contributions to the total packing energy in a ratio of 2:1 with respect to the latter.

The synthesis, crystal structure and structural motif of two thio­phene-based cyano­acrylate derivatives, namely, ethyl (E)-2-cyano-3-(3-methyl­thio­phen-2-yl)acrylate (1), C11H11NO2S, and ethyl (E)-2-cyano-3-(thio­phen-2-yl)acrylate (2), C10H9NO2S, are reported. Derivative 1 crystallized with two independent molecules in the asymmetric unit, and derivative 2 represents a new monoclinic (C2/m) polymorph. The mol­ecular conformations of 1 and the two polymorphs of 2 are very similar, as all non-H atoms are planar except for the methyl of the ethyl groups. The inter­molecular inter­actions and crystal packing of 1 and 2 are described and compared with that of the reported monoclinic (C2/m) polymorph of derivative 2 [Castro Agudelo et al. (2017). Acta Cryst. E73, 1287–1289].

1-(2-Iodo­benzo­yl)-cyclo­pent-3-ene-1-carboxyl­ates are novel substrates to construct bi­cyclo­[3.2.1]octa­nes with anti­bacterial and anti­thrombotic activities. In this context, tert-butyl 1-(2-iodo­benzo­yl)-cyclo­pent-3-ene-1-carboxyl­ate, C17H19IO3, was synthesized and structurally characterized. The 2-iodo­benzoyl group is attached to the tertiary C atom of the cyclo­pent-3-ene ring. The dihedral angle between the benzene ring and the mean plane of the envelope-type cyclo­pent-3-ene ring is 26.0 (3)°. In the crystal, pairs of C-H⋯O hydrogen bonds link the mol­ecules to form inversion dimers.

The structure of the title complex, [Ag(C11H15N3S)2]PF6, has monoclinic (P21/c) symmetry, and the silver atom has a distorted square-planar geometry. The coordination complex crystallized from mixing silver hexa­fluorido­phosphate with a concentrated tetra­hydro­furan solution of N,N-di­ethyl­phenyl­azo­thio­formamide [ATF; systematic name: 3,3-diethyl-1-(phenyl­imino)­thio­urea] under ambient conditions. The resultant coordination complex exhibits a 2:1 ligand-to-metal ratio, with the silver(I) atom having a fourfold AgN2S2 coordination sphere, with a single PF6 counter-ion. In the crystal, however, one sulfur atom from an ATF ligand of a neighboring complex coordinates to the silver atom, with a bond distance of 2.9884 (14) Å. This creates a polymeric zigzag chain propagating along the c-axis direction. The chains are linked by C—H⋯F hydrogen bonds, forming slabs parallel to the ac plane.

The structure of the title compound (systematic name: N-{[(2-hy­droxy­phen­yl)methyl­idene]amino}­morpholine-4-carbo­thio­amide), C12H15N3O2S, was prev­iously determined (Koo et al., 1977) using multiple-film equi-inclination Weissenberg data, but has been redetermined with higher precision to explore its conformation and the hydrogen-bonding patterns and supra­molecular inter­actions. The mol­ecular structure shows intra­molecular O—H⋯N and C—H⋯S inter­actions. The configuration of the C=N bond is E. The mol­ecule is slightly twisted about the central N—N bond. The best planes through the phenyl ring and the morpholino ring make an angle of 43.44 (17)°. In the crystal, the mol­ecules are connected into chains by N—H⋯O and C—H⋯O hydrogen bonds, which combine to generate sheets lying parallel to (002). The most prominent contribution to the surface contacts are H⋯H contacts (51.6%), as concluded from a Hirshfeld surface analysis.

In the title pyrazoline derivative, C16H16N2O3·H2O, the pyrazoline ring has an envelope conformation with the substituted sp2 C atom on the flap. The pyrazoline ring makes angles of 86.73 (12) and 13.44 (12)° with the tris­ubstituted and disubstituted benzene rings, respectively. In the crystal structure, the mol­ecules are connected into chains running in the b-axis direction by O—H⋯N hydrogen bonding. Parallel chains inter­act through N—H⋯O hydrogen bonds and π–π stacking of the tris­ubstituted phenyl rings. The major contribution to the surface contacts are H⋯H contacts (44.3%) as concluded from a Hirshfeld surface analysis.

Strontium tetra­gallate(II,III) tetra­arsenide, SrGa4As4, was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 8 GPa and 1573 K. The com­pound crystallizes in a new structure type (P3221, Z = 3) as a three-dimensional (3D) framework of corner-sharing SrAs8 quadratic anti­prisms with strontium situated on a twofold rotation axis (Wyckoff position 3b). This arrangement is surrounded by a 3D framework which can be described as alternately stacked layers of either condensed GaIIIAs4 tetra­hedra or honeycomb-like layers built up from distorted ethane-like GaII2As6 units com­prising Ga—Ga bonds.

In the crystal structure of the title com­pound, [Ni(NCS)2(CH3CN)2(C12H9NO)2] or Ni(NCS)2(4-benzoyl­pyridine)2(aceto­nitrile)2, the NiII ions are octa­hedrally coordinated by the N atoms of two thio­cyanate anions, two 4-benzoyl­pyridine ligands and two aceto­nitrile mol­ecules into discrete com­plexes that are located on centres of inversion. In the crystal, the discrete com­plexes are linked by centrosymmetric pairs of weak C—H⋯S hydrogen bonds into chains. Thermogravimetric measurements prove that, upon heating, the title com­plex loses the two aceto­nitrile ligands and transforms into a new crystalline modification of the chain com­pound [Ni(NCS)2(4-benzoyl­pyridine)2], which is different from that of the corresponding CoII, NiII and CdII coordination polymers reported in the literature. IR spectroscopic investigations indicate the presence of bridging thio­cyanate anions but the powder pattern cannot be indexed and, therefore, this structure is unknown.

The title mol­ecular salt, C9H12N3O2S+·HSO4−, was obtained through the protonation of the azomethine N atom in a sulfuric acid medium. The crystal com­prises two entities, a thio­semicarbazide cation and a hydrogen sulfate anion. The cation is essentially planar and is further stabilized by a strong intra­molecular O—H⋯N hydrogen bond. In the crystal, a three-dimensional network is established through O—H⋯O and N—H⋯O hydrogen bonds. A weak intermolecular C—H⋯O hydrogen bond is also observed. The hydrogen sulfate anion exhibits disorder over two sets of sites and was modelled with refined occupancies of 0.501 (6) and 0.499 (6).

The title compound, C14H14N2S2, was obtained by transmetallation of 2,2'-bis­(tri­methyl­stann­yl)azo­benzene with methyl lithium, and subsequent quenching with dimethyl di­sulfide. The asymmetric unit comprises two half-mol­ecules, the other halves being completed by inversion symmetry at the midpoint of the azo group. The two mol­ecules show only slight differences with respect to N=N, S—N and aromatic C=C bonds or angles. Hirshfeld surface analysis reveals that except for one weak H⋯S inter­action, inter­molecular inter­actions are dominated by van der Waals forces only.