Heterocyclic Thiones Research Articles

Coordination Polymers of Copper(I) Halides and Neutral Heterocyclic Thiones with New Coordination Modes

Reaction of copper(I) chloride or bromide with equimolar amounts of the neutral pyrimidine-2-thione ligand (pymtH) afforded linear chain polymers [Cu(pymtH)X]n (X = Cl, Br) with the pymtH ligand acting as a bridging N, S donor. In contrast, copper(I) iodide under the same conditions gave the dimeric complex [Cu(pymtH)2I]2 with the pymtH ligand adopting monodentate coordination mode through the exocyclic sulfur atom in terminal and bridging modes. Reactions of the heterocyclic thione ligand 2,4,6-trimercaptotriazine (H3TMT) with copper(I) halides afforded novel three-dimensional polymers, which crystallized in the cubic space group Pa. Each copper(I) ion is coordinated by three S atoms of three distinct H3TMT ligands, and each H3TMT acts as a tridentate bridging ligand linking three copper(I) ions through its sulfur atoms, thus forming two independent three-dimensional (3D) networks. The network belongs to a three-connected (10, 3)-a topology, which is enantiometric and interpenetrating. In all complexes the ligands are present in the thione form, and all halides are terminally coordinated to copper(I) ions. The photoluminescent and thermal properties of the complexes have also been investigated.

Polymer and cage-type structures in silver(I) complexes with heterocyclic thiones and bridging diphosphine ligands. Crystal structures of [Ag(μ-dpppent)(tHpymtH)(ONO 2)] n and [Ag 2(μ- trans-dppen) 3(pymtH) 2](NO 3) 2 · CH 3CN

Reaction of silver(I) nitrate with equimolar amounts of the rigid diphos ligand trans-1,2-bis(diphenylphosphino)ethene ( trans-dppen) and some heterocyclic thiones (L) in acetonitrile/methanol solvent gave rise to triply-bridged coordination cages [Ag 2(μ 2- trans-dppen) 3L 2](NO 3) 2. On the other hand, the complexes produced when using the flexible 1,5-bis(diphenylphosphino)pentane (dpppent) turned out to be diphosphine-bridged polymers of the type [Ag(μ 2-dpppent)(L)(ONO 2)] n with the diphosphine ligand acting as bridge between two pseudo-tetrahedraly coordinated metal centres. The structures of one representative for each of the two aforementioned series of complex compounds, namely, [Ag 2(μ 2- trans-dppen) 3(pymtH) 2](NO 3) 2 (pymtH = pyrimidine-2-thione) and [Ag(μ 2-dpppent)(tHpymtH) (ONO 2)] n (tHpymtH = tetrahydropyrimidine-2-thione) have been established by single-crystal X-ray diffraction.

Heterocyclic Thiones and Their Analogues in Reactions of 1,3‐Dipolar Cycloaddition. Part 3. Reaction of Benzothiazole‐2‐thione with a Double Excess of Nitrilimine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Linking thione-ligated copper(I) centres with trans-1,2-bis(diphenylphosphino)ethene ( trans-dppen): crystal structures of the pyrimidine-2-thione derivatives [CuBr(μ 2- trans-dppen)(pymtH)] 2 and [CuI(μ 2- trans-dppen)(pymtH)] 2

Several mixed-ligand complexes of the composition [CuX( trans-dppen)(L)] (X = Br, I) have been prepared by treatment of copper(I) halide with equimolar amounts of trans-1,2-bis(diphenylphosphino)ethene ( trans-dppen) in acetonitrile followed by the addition of a methanolic solution of one equivalent of a heterocyclic thione (L). The novel complex compounds have been characterized by 1H NMR and IR spectroscopy as well as by elemental analyses and melting points. The X-ray structures of two representative examples, namely the pyrimidine-2-thione complexes of copper(I) bromide and iodide confirm that the compounds are dimers of type [CuX(μ 2- trans-dppen)(L)] 2 containing two tetrahedral coordination units joined by two diphosphine bridges.

Heterocyclic Thiones and Their Analogs in Reactions of 1,3-Dipolar Cycloaddition: III. Reaction of Benzothiazole-2-thione with a Double Excess of Nitrilimine

Main products of reaction between benzothiazole-2-thione and a double excess of nitrilimine are substituted 1-aryl-1-(1,3-benzothiazol-2-yl)-2-(2,3-dihydro-1,3,4-thiadiazol-2-yl)hydrazines. In the first step presumably forms a spiro compound via 1,3-dipolar cycloaddition of nitrilimine molecule to the C=S bond of the benzothiazolethione. The second nitrilimine molecule adds to the new C=S bond of the intermediate product arising by the rupture of CS bond in the thiadiazole ring of the spiro compound.

Trans-1,2-bis(diphenylphosphino)ethene as bridging ligand in thione-S-ligated dimeric copper(I) chloride complexes

Several mixed-ligand complexes have been prepared by treatment of copper(I) chloride with equimolar amounts of trans-1,2-bis(diphenylphosphino)ethene ( trans-dppen) in acetonitrile followed by the addition of a methanolic solution of one equivalent of a heterocyclic thione (L). The novel complex compounds have been characterized by single-crystal X-ray diffraction, 1H NMR and IR spectroscopy as well as by elemental analyses and melting points. The X-ray structures of three examples confirm that the compounds are homobimetallic dimers of type [CuCl(μ 2- trans-dppen)(L)] 2 containing two tetrahedral coordination units joined by two trans-dppen bridges.

Diphosphines as bridging ligands in polymeric and dimeric thione-S-ligated Ag(I) nitrate complexes

Reactions of silver(I) nitrate with equimolar amounts of the diphos ligands 1,4-bis(diphenylphosphino)butane (dppb) or 1,2-bis(diphenylphosphino)ethane (dppe) and some heterocyclic thiones (L) in acetonitrile/methanol solvent afforded mixed-ligand complexes, the nature of which was found to be strongly influenced by the backbone length of the diphosphine ligand. The longer chained diphos ligand formed a series of dinuclear complexes of the type [Ag(dppb)(L)] 2(NO 3) 2 with both the diphosphine and thione ligands acting as bridging ligands between the two four-coordinate pseudo-tetrahedrally coordinated metal centers. In the unique case of L=4-methyl-5-trifluoromethyl-4H-1,2,4-triazoline-3(2H)-thione (mftztH), the reaction proceeded under exclusion of the thione ligand from the coordination sphere and coordination of the nitrate anions instead, leading to the diphosphine-doubly bridged dimeric compound [Ag(dppb)(NO 3)] 2. On the other hand, the complexes produced when using the short bite 1,2-bis(diphenylphosphino)ethane (dppe) turned out to be diphosphine-bridged cationic polymers of the type [Ag(dppe)(L) 2] n (NO 3) n . The structures of one representative for each of the two aforementioned series of complex compounds, namely [Ag(dppb)(py2SH)] 2(NO 3) 2 · 2H 2O and [Ag(dppe)(pymtH) 2] n (NO 3) n , have been established by single-crystal X-ray diffraction.

Complexes of heterocyclic thiones and group 12 metals: Part VI. Preparation and characterisation of complexes of cadmium(II) halides with 1-methylimidazoline-2(3H)-thione, 1,3-thiazolidine-2-thione and 1,3-benzothiazoline-2-thione. Crystal structures of polymeric (1,3-thiazolidine-2-thione)cadmium(II) chloride, bis(1,3-thiazolidine-2-thione)cadmium(II) iodide and monomeric bis(1-methylimidazoline-2(3H)-thione)cadmium(II) bromide

Reactions of 1-methylimidazoline-2(3H)-thione (meimz2SH), 1,3-thiazolidine-2-thione (tzdSH) and 1,3-benzothiazoline-2-thione (bztzSH) with cadmium(II) halides in ethanol solutions result in the formation of 1:1 complexes for the chloride, both 1:1 and 2:1 complexes for the bromide, and only 2:1 complexes for the iodide. Spectroscopic evidence confirms the exocyclic sulfur atom to be the donor in all cases. Cadmium(II) acetate and the heterocyclic ligands in the presence of triethylamine form the insoluble deprotonated complexes. The structure of (tzdSH)CdCl 2 consists of double halogen-bridged chains, linked into sheets via NH⋯Cl interactions and with the heterocycle coordinated to the metal via the exocyclic sulfur atom. Thus each cadmium is approximately octahedrally surrounded by one sulfur, 2 two-coordinate and 3 three-coordinate chlorine atoms. In contrast (tzdSH) 2CdI 2 forms chains via I⋯S interactions; the metal is tetrahedrally coordinated by two sulfur and two iodine atoms. The structure of (meimz2SH) 2CdBr 2 consists of discrete complex molecules with essentially tetrahedrally coordinated Cd and no significant intermolecular interactions; the six molecules in the asymmetric unit are related by pseudo-symmetry and are very similar except for variation in the orientation of the heterocyclic substituents.

Copper(I) halide complexes from cis-1,2-bis(diphenylphosphino) ethylene and some heterocyclic thiones

Reaction of copper(I) chloride or bromide with equimolar amounts of the diphos ligand cis-1,2-bis(diphenylphosphino)ethylene (dppet) and a heterocyclic thione (L) in acetonitrile/methanol solvent afforded mononuclear complexes of the type [CuX(dppet)(L)] with the diphosphine ligand acting as a chelating ligand. However, the same reaction carried out at higher temperatures proceeds, in some cases, with exclusion of the phosphine ligand from the coordination sphere leading to double-S-bridged dimers. In contrast, copper(I) iodide under the same conditions gave the thione-free dimeric compound [CuI(dppet)]2 which contains double-bridging iodine atoms. A notable exception was for the reaction with 5-methyl-1,3,4-thiadiazole-2-thione (mtdztH) which, under the same conditions, gave rise to the unexpected, simultaneous formation of the monomer [CuI(dppet)(CH3CN)] as well as the above mentioned dimeric [CuI(dppet)]2. Furthermore treatment [CuX(dppet)(L)] with two equivalents of triphenylphosphine was found to cause replacement of the diphos ligand, while substitution of the chlorine atom under HCl elimination and formation of [Cu(dppet)(mftztH)2] occured in the unique case of treating [CuCl(dppet)(mftztH)] with one additional equivalent of the same thione ligand. The structures of one representative for each of the above mentioned types of complexes, namely [CuBr(dppet)(mftztH)], [Cu(dppet)(mftztH)2], [Cu(μ-I)(dppet)]2·[CuI(dppet)(CH3CN)] and [CuBr{μ-S(pymtH)}(pymtH)]2 have been established by single-crystal X-ray diffraction.

Metal–Heterocyclic thione interactions-15 – reactivity of coordinated thiones of bis(pyridine- 2-thiolato- or 1-oxopyridine- 2-thiones)palladium(II)/platinum(II) towards divalent metal halides: synthesis of polynuclear complexes

Reactions of dinuclear tetrakis(pyridine-2-thiolato)dipalladium(II) or platinum(II), M2(C5H4NS)4, with divalent metal halides in organic solvents formed compounds of stoichiometry: [M2(C5H4NS)4·(M′X2)2] {M = Pd, M′X2 = HgCl2 (1), PtCl2 (2), CdCl2 (3); M = Pt, M′X2 = HgCl2 (4)}. Similarly, bis(1-oxopyridine-2-thione)-palladium(II)/platinum(II) formed compounds: [M(C5H4NOS)2·M′X2] {M = Pd, M′X2 = HgCl2 (5), HgBr2 (6), HgI2 (7), CdCl2 (8), PtCl2 (9); M = Pt, M′X2 = HgBr2 (10), HgI2, (11)}. Compounds 1–11 have been characterized using elemental analysis, IR, far-IR, and NMR (1H, 13C) spectroscopy. Coordination to metal centers of M′X2 occurs via coordinated sulfur. Possible structures are suggested. The crystallization of (5) in dimethyl sulfoxide formed crystals of Pd(C5H4NOS)2 as revealed by X-ray crystallography.

New Method for the Synthesis of 1,2,3,6,7,11b‐Hexahydro‐4H‐pyrimido[6,1‐a]isoquinoline‐4‐thiones and 2,3,6,7,12,12b‐Hexahydropyrimido[6,1‐a]‐β‐carboline‐4(1H)‐thiones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reactions of Stable α‐Chlorosulfanyl Chlorides with CS‐Functionalized Compounds

AbstractThe smooth reaction of 3‐chloro‐3‐(chlorosulfanyl)‐2,2,4,4‐tetramethylcyclobutanone (3) with 3,4,5‐trisubstituted 2,3‐dihydro‐1H‐imidazole‐2‐thiones 8 and 2‐thiouracil (10) in CH2Cl2/Et3N at room temperature yielded the corresponding disulfanes 9 and 11 (Scheme 2), respectively, via a nucleophilic substitution of Cl− of the sulfanyl chloride by the S‐atom of the heterocyclic thione. The analogous reaction of 3‐cyclohexyl‐2,3‐dihydro‐4,5‐diphenyl‐1H‐imidazole‐2‐thione (8b) and 10 with the chlorodisulfanyl derivative 16 led to the corresponding trisulfanes 17 and 18 (Scheme 4), respectively. On the other hand, the reaction of 3 and 4,4‐dimethyl‐2‐phenyl‐1,3‐thiazole‐5(4H)‐thione (12) in CH2Cl2 gave only 4,4‐dimethyl‐2‐phenyl‐1,3‐thiazol‐5(4H)‐one (13) and the trithioorthoester derivative 14, a bis‐disulfane, in low yield (Scheme 3). At −78°, only bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutyl)polysulfanes 15 were formed. Even at −78°, a 1 : 2 mixture of 12 and 16 in CH2Cl2 reacted to give 13 and the symmetrical pentasulfane 19 in good yield (Scheme 5). The structures of 11, 14, 17, and 18 have been established by X‐ray crystallography.

Synthesis and X‐ray Structures of Tin(IV) and Lead(II) Complexes with Heterocyclic Thiones

AbstractTin(IV) and lead(II) complexes of 3‐(trifluoromethyl)pyridine‐2‐thione (3‐CF3‐pySH) and 5‐(trifluoromethyl)pyridine‐2‐thione (5‐CF3‐pySH) have been synthesised. The compounds [Sn(3‐CF3‐pyS)4] (1), [Sn(5‐CF3‐pyS)4] (2), [Pb(3‐CF3‐pyS)2] (3), and [Pb(5‐CF3‐pyS)2] (4) were obtained by addition of the appropriate ligand to a methanol solution of tin(II) chloride or lead acetate in the presence of triethylamine. The complex [Sn(5‐CF3‐pyS)4] was also prepared by electrochemical oxidation of a tin anode in a cell containing an acetonitrile solution of the ligand 5‐(trifluoromethyl)pyridine‐2‐thione. The X‐ray crystal structure of [Sn(3‐CF3‐pyS)4] reveals a dodecahedral coordination geometry around SnIV, with the four thionate ligands acting in a bidentate (N,S) manner. [Sn(5‐CF3‐pyS)4] also consists of monomeric neutral molecules with the tin(IV) atom in an octahedral geometry with two bidentate (N,S) ligands and two monodentate S ligands. The molecular structure of [Pb(3‐CF3‐pyS)2] shows the metal in a five‐coordinate geometry with the stereochemically active lead(II) lone pair in an equatorial position of a trigonal bipyramid. Spectroscopic data for the complexes (IR, NMR, FAB, and Mössbauer spectra) are discussed and related to the structural information. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

New Method for the Synthesis of 1,2,3,6,7,11b-Hexahydro-4H-pyrimido[6,1-a]isoquinoline-4-thiones and 2,3,6,7,12,12b-Hexahydropyrimido[6,1-a]-β-carboline-4(1H)-thiones

Pyrimido[6,1-a]isoquinolines hold interest as physiologically active compounds [1]. The structural fragment of pyrimido[6,1-a]-β-carbolines is found in several alkaloids such as elaeocapridine [2]. The methods reported for the preparation of such compounds involve multiple steps and have proved inefficient. As a rule, the synthesis of such compounds requires not readily available isoquinoline and β-carboline precursors. The pyrimidine ring is subsequently completed [3]. On the other hand, intramolecular amidoalkylation of heterocyclic acyliminium is often used for the preparation of isoquinolines and β-carbolines fused with other heterocycles [4]. Such an approach to the synthesis of pyrimido[6,1-a]isoquinolines and pyrimido[6,1-a]-βcarbolines has not yet been employed. We have shown that 6-hydroxytetrahydropyrimidine-2-thiones 5, obtained according to Unkovskii et al. [5] by the reaction of the corresponding isothiocyanatocarbonyl derivatives 1a and 1b [6] with homoveratrylamine 3 or tryptamine 4, are converted upon heating in acetic acid to 1,2,3,6,7,11b-hexahydro-4Hpyrimido[6,1-a]isoquinoline-4-thiones 8a and 8b and 2,3,6,7,12,12b-hexahydropyrimido[6,1-a]-β-carboline4(1H)-thiones 9a and 9b with satisfactory yields (method A). Thione 8b is formed as a 10:9 2,11b-cis/trans isomer mixture while thione 9b is formed as a 1:4 1,12b-cis/trans isomer mixture. Heterocyclic cation 6 may also be obtained from 3,4-dihydropyrimidine-2(1H)-thione 7 in acid medium. The use of amines 3 and 4 in reported methods for the synthesis of 7 based on the condensation of isothiocyanato ketones and amines [7] (method B) or of α,β-unsaturated ketones, thiocyanic acid, and amines [8] (method C) also leads to heterocyclic thiones 8 and 9 (Scheme 1). The yields of 8a relative to amine 3 obtained by methods A (overall yield in two steps), B, and C are 73, 65, and 64%, respectively. The reaction proceeds as an intramolecular amidoalkylation of the aryl or hetaryl fragment by heterocyclic cation 6 formed in acid medium from 5 or 7. General Method for the Synthesis of 8 and 9 (Method B). A mixture of isothiocyanatocarbonyl derivative (72.3 mmol) and 3,4-dimethoxyphenylethylamine (60.5 mmol) in glacial acetic acid (50 ml) was heated at reflux for 1.5 h. The reaction mixture was cooled to room temperature and poured onto ice. The crystals formed were filtered off, dried, and recrystallized from absolute ethanol.

Copper(I) halide complexes with 1,3-propanebis(diphenylphosphine) and heterocyclic thione ligands: crystal and electronic structures (DFT) of [CuCl(pymtH)(dppp)], [CuBr(pymtH)(dppp)], and [Cu(mu-I)(dppp)](2).

Reaction of copper(I) chloride or bromide with equimolar amounts of the diphos ligand 1,3-propanebis(diphenylphosphine) and a heterocyclic thione (L) in acetonitrile/methanol solvent afforded mononuclear complexes of the type [CuX(dppp)(L)] with the diphosphine ligand acting as a chelating ligand. In contrast, copper(I) iodide under the same conditions gave the dimeric complex [Cu(mu-I)(dppp)](2), which contains doubly bridging iodo ligands. The structures of three complexes, namely, [CuCl(pymtH)(dppp)], [CuCl(pymtH)(dppp)], and [Cu(mu-I)(dppp)](2), have been established by single-crystal X-ray diffraction. Density functional calculations at the B3LYP level of theory provided a satisfactory description of the structural, bonding, electronic, and related properties of the [CuX(PH(3))(2)] and [CuX(1,3-pdp)] (1,3-pdp = 1,3-propane-di-phosphine) complexes and their dimers along with their associations with the pyrimidine-2-thione (pymtH) ligand. The interaction of the pymtH ligand with the Cu(I) metal center in these complexes corresponds to loose associations, the computed interaction energies predicted to be about 20 kcal/mol for all complexes in the series. The bonding mechanism of the thione ligand with the Cu(I) metal centers involves both a sigma-dative and pi-back-bonding components. The coordination of the pymtH ligand is further stabilized by X...H-N bond formation being more pronounced in the chloro than in the iodo derivatives. The Cu-X bond was also found to be a composite bond involving sigma- and pi-dative bonding components. Most important is the presence of pi-type MOs delocalized over the entire four-membered Cu(mu-X)(2)Cu ring, which supports a ring current and could probably account for the nearly equivalent Cu-X bonds in the rhombus. Moreover, all [Cu(mu-X)(PH(3))(2)](2) dimers exhibit a sigma-type MO corresponding to weak Cu.Cu interactions supporting through-ring intermetallic interactions, which seems to be responsible for the stabilization of the otherwise unstable antiaromatic Cu(mu-X)(2)Cu ring.

Metal–heterocyclic thione interactions. 13. Pyridine-2-thione derivatives of copper(I): crystal structure of dinuclear [bromo(pyridine-2-thione)(tri- p-tolylphosphine)copper(I)] 2 complex

The sulfur-bridged dinuclear copper (I) complex, [CuBr(η 2-Sμ-C 5H 5NS)( p-Tol 3P)] 2 ( 1) was prepared by the reaction of insoluble CuBr 2(C 5H 5NS) 2 {from copper(II) bromide and pyridine-2-thione(C 5H 5NS) in ethanol} with excess tri- p-tolylphosphine ( p-Tol 3P) in chloroform (1:2 mole ratio). Similarly, other copper(I) complexes of stoichiometry [CuX(C 5H 5NS)(Ph 3P)] 2 {X=Cl, 2 and I, 3} were prepared. Compound 1 crystallised from a dichloromethane–chloroform–methanol mixture and exists as a centrosymmetric sulfur-bridged dimer with distorted tetrahedral geometry about each Cu atom; the other two positions of each Cu atom being occupied by a P atom from p-Tol 3P and a bromine atom. The central core Cu 2S 2 of the dimer is a parallelogram with the important interatomic parameters as follows: CuP, 2.2376(13), CuS, 2.3895(19), 2.415(2), CuBr, 2.4455(11), SC(2), 1.717(4), CuCu*, 3.250(2), SS*, 3.539(3) Å; CuSCu*, 85.14(6), SCuS*, 94.86(6), CuSC(2), 108.41(14), 113.12(16)°. The dimer structure is stabilised by strong intramolecular NH⋯Br hydrogen bonds [3.319(5) Å]. The X-ray study of 2 showed that it has transformed into monomer [CuCl(η 1-Sμ-C 5H 5NS)(Ph 3P) 2] ( 4) during crystal growth. The strong intramolecular NH⋯Cl hydrogen bonding appears to stabilise the monomer. All the compounds were characterised using analytical data, IR and far-IR (4000–100 cm −1), UV–Vis spectra, NMR ( 1H, 13C) and for 1 and 4 using X-ray crystallography. The factors controlling Cu⋯Cu interaction in the sulfur-bridged dinuclear copper(I)-heterocyclic thione complexes are described.

Dichlorobis(1-propylimidazolidine-2-thione-kappaS)cobalt(II).

The crystal structure of the title compound, [CoCl(2)(C(6)H(12)N(2)S)(2)], consists of monomer units of a Co(II) atom coordinated to two 1-propylimidazolidine-2-thione ligands and to two chloride ions. The heterocyclic thione ligand is monodentate and coordinated to the metal through the thione S atom. The environment around the Co(II) atom is a slightly distorted tetrahedron. The Co-S bond lengths are 2.341 (2) and 2.330 (2) A, and the Co-Cl bond lengths are 2.234 (2) and 2.238 (2) A. The most important point of distortion is the S-Co-S bond angle of only 97.83 (8) degrees. Intramolecular classical hydrogen bonds are found between the chloride ions and the N-H groups. Additionally, intra- and intermolecular non-classical hydrogen bonds are found.

Syntheses and Characterization of New Copper Complexes with the Heterocyclic Thione, AMTTO. X-Ray Structures of [Cu(AMTTO)Cl2], [Cu(AMTTO)2]Cl, and [Cu(AMTTO)(PPh3)2Cl] (AMTTO = 4-Amino-6-methyl-1, 2, 4-triazine-3-thione-5-one)

The complexes [Cu(AMTTO)Cl2] (2), [Cu(AMTTO)2]Cl (3), and [Cu(AMTTO)(PPh3)2Cl] (4) have been prepared and characterized by IR spectroscopy and elemental analyses. Also single-crystal X-ray diffraction studies on compound 2, 3 and 4 revealed that AMTTO acts in 2 as a bidentate ligand via nitrogen and sulfur atoms, in 3 and 4 as a monodentate via sulfur atoms. Complex 3 was already mentioned in literature, but the structure was not described in detail. The molecules in 2 form infinite chains through additional weak Cu—S interactions along [010] indicating the Jahn-Teller distortion of the d9 ion Cu2+. The infinite chains are connected by hydrogen bonding along [100]. Crystal data for 2 at —80°C: monoclinic, space group P21/m, a = 666.7(1), b = 609.4(1), c = 1132.6(2) pm, b = 95.46(2)°, Z = 2, R1 = 0.0365; for 3 at —80°C: orthorhombic, space group Pbcn, a = 1291.2(2), b = 1146.5(1), c = 1000.5(1) pm, Z = 4, R1 = 0.0315; for 4 at —80°C: monoclinic, space group, P21/n, a = 879.4(1), b = 1849.3(2), c = 2293.8(3) pm, β = 92.38(1)°, Z = 4, R1 = 0.0688. Synthesen und Charakterisierung von neuen Kupfer-Komplexen des heterocyclischen Thions AMTTO. Die Kristallstrukturen von [Cu(AMTTO)Cl2], [Cu(AMTTO)2]Cl und [Cu(AMTTO)(PPh3)2Cl] (AMTTO = 4-Amino-6-methyl-1, 2, 4-triazin-3-thion-5-on) Über die Darstellung der Komplexe [Cu(AMTTO)Cl2] (2), [Cu(AMTTO)2]Cl (3) sowie [Cu(AMTTO)(PPh3)2Cl] (4) und deren Charakterisierung mittels IR-Spektroskopie and Elementaranalysen wird berichtet. Die zusätzlich an 2, 3 und 4 durchgeführten Röntgenstrukturanalysen ergaben, daß der Ligand AMTTO in 2 als zweizähniger Ligand über Stickstoff- und Schwefelatome koordiniert, dagegen in 3 und 4 nur als einzähniger Ligand über die Schwefelatome fungiert. Komplex 3 wurde bereits in der Literatur erwähnt, jedoch wurde der dreidimensionale Aufbau dort nicht ausführlich beschrieben. Die Moleküle von 2 bilden durch zusätzliche schwache Cu—S-Kontakte unendliche Ketten entlang [010], was die Jahn-Teller-Verzerrung des d9-Ions Cu2+ belegt. Diese Polymerstränge sind untereinander durch Wasserstoffbrücken-Bindungen entlang [100] verknüpft.Strukturparameter für 2 bei —80°C: monoklin, Raumgruppe P21/m, a = 666, 7(1), b = 609, 4(1), c = 1132, 6(2) pm, β = 95, 46(2)°, Z = 2, R1 = 0, 0365; für 3 bei —80°C: orthorhombisch, Raumgruppe Pbcn, a = 1291, 2(2), b = 1146, 5(1), c = 1000, 5(1) pm, Z = 4, R1 = 0, 0315; für 4 bei —80°C: monoklin, Raumgruppe P21/n, a = 879, 4(1), b = 1849, 3(2), c = 2293, 8(3) pm, β = 92, 38(1)°, Z = 4, R1 = 0, 0688.

ADDITIONS AND CORRECTIONS/AJOUTS ET CORRECTIONSAdditions and corrections: Solution multinuclear (31P,111Cd,77Se) magnetic resonance studies of cadmium complexes of heterocyclic aromatic thiones and the structure of [tetrakis(2(1H)-pyridinethione)cadmium] nitrate, [Cd(C5H5NS)4](NO3)2

<b>ADDITIONS AND CORRECTIONS/AJOUTS ET CORRECTIONS</b>Additions and corrections: Solution multinuclear (³¹P,¹¹¹Cd,⁷⁷Se) magnetic resonance studies of cadmium complexes of heterocyclic aromatic thiones and the structure of [tetrakis(2(1<i>H</i>)-pyridinethione)cadmium] nitrate, [Cd(C₅H₅NS)₄](NO₃)₂

Kinetics and mechanism of the formation and reactions of S-nitroso derivatives of some heterocyclic thiones

Rate and equilibrium measurements have been obtained for the nitrosation (using nitrous acid in dilute acid aqueous solution) of the following thione–thiol nitrogen heterocyclic species and for the decomposition reactions of the formed S-NO+ ions: 4-mercaptopyridine (1), 2-mercaptopyridine 1-oxide (2), 2-mercaptopyrimidine (3) and 2-mercapto-1H-imidazole (4). The nitrosation reactions were all rapid and rate constants were obtained by stopped-flow spectrophotometry. In all cases kinetic analysis showed that the halide ion-catalysed and the uncatalysed reactions occurred at or close to the diffusion-controlled limit and the reactive form of the substrate is its thione form. In some cases at high [nitrous acid] reaction occurred via N2O3 where the rate-limiting step is that of N2O3 formation. Similarly reaction of 1 and 3 in the presence of thiocyanate showed that reaction takes place via rate-limiting formation of ONSCN. All of the nitrosation reactions were somewhat reversible, with large equilibrium constants of 2.0 × 107, ∼4 × 105, 1.7 × 103 and 1.5 × 105 dm6 mol−2 respectively for 1, 2, 3, and 4. All of the S-NO+ ions decomposed rapidly in solution generating the disulfides and nitric oxide. This reaction was monitored only for the S-NO+ derived from 1 and 2 because of stability problems. The deprotonated form of the S-nitroso product from 1 was identified from measurements at pH 7.4 and the pKa value of the protonated form estimated as 4.5. It decomposed fairly rapidly to give the thione. We report some results where thiones show considerable catalytic activity in nitrosation reactions of N-methylaniline and ascorbic acid.