Heterocyclic Thione Ligands Research Articles

Role of C–H···Au and Aurophilic Supramolecular Interactions in Gold–Thione Complexes

The role of noncovalent gold–hydrogen and aurophilic interactions in the formation of extended molecular systems of gold complexes was studied. Three new gold compounds with a heterocyclic thione ligand N-methylbenzothiazole-2-thione (mbtt), namely, [AuCl(mbtt)] (1), [AuBr(mbtt)] (2), and [Au(mbtt)2][AuI2]1–n[I3]n (3), were synthesized and characterized. The halide ligand had a considerable effect on the complex structures and thus to noncovalent contacts. Intermolecular C–H···Au and aurophilic Au···Au contacts were the dominant noncovalent interactions in structures 1–3 determining the supramolecular arrays of the gold complexes. In 1 and 2, unusual intermolecular C–H···Au gold–hydrogen contacts linked the adjacent mononuclear molecules to a chain structure, while in 3 the change in the ligand coordination induced the formation of an intermolecular aurophilic interaction. Au···I, π–π, halogen–halogen, and hydrogen bonding interactions supported further the supramolecular array of 3. The interactions were...

In situ amination and side group effect of multifunctional heterocyclic thione ligand toward discrete and polymeric cluster constructions

Three metal complexes [Cu(I)6(atdm)6] (1), [Cu(I)(Hatd)(H2atd)] (2) and [H3O][Co(II)4Co(III)2Cl3(atd)6]·H2O (3) [atdm = 4-dimethylamino-6-anilino-1,3,5-triazine-2-thiolate, H2atd = 6-anilino-1,3,5-triazine-2,4-dithiol, atdH2 = 6-anilino-1,3,5-triazine-2,4(1H,3H)-dithione] have been solvothermally synthesized. The luminescent complexes 1 and 2 provide remarkable structural diversity depending on different reaction solutions. Complex 1 consists of a discrete pseudohexagonal prismatic [Cu6S6] core that can be described as two stacked, chair-shaped [Cu3S3] rings bound together by the C-N bridges of the atdm ligands, in which the atdm ligand was generated via in situ amination of H2atd in the presence of DMF solution. Whereas complex 2 is a 2D (4,4) net based on single node Cu(I) ions crystallized in acetonitrile, in which H2atd ligands exist in the thione form atdH2 and the partially deprotonated form atdH. Complex 3 has a two-fold interpenetrated (10,3)-a topological network based on unprecedented cobalt-centered trigonal-bipyramidal [Co6(atd)6] building blocks, linked by Cl(-) double-bridges and showing oriented effects of aniline side groups. IR spectra, elemental analyses and XRD analyses confirmed the phase-purities of the as-synthesized complexes. The photoluminescence properties of 1 and 2 in the solid state and the magnetic properties of 3 are investigated. A discussion of the crystal structures, as well as the coordination properties of the multifunctional sulfur-containing ligands upon different geometries of the central units, is also provided.

ChemInform Abstract: Pharmaceutical Importance and Synthetic Strategies for Imidazolidine‐2‐thione and Imidazole‐2‐thione Derivatives

AbstractReview: 57 refs.

Pharmaceutical Importance and Synthetic Strategies for Imidazolidine-2-thione and Imidazole-2-thione Derivatives

Imidazole heterocycles containing oxygen or sulfur heteroatoms are of considerable pharmaceutical interest. Many synthetic strategies for imidazolidine-2-thione and imidazole-2-thione derivatives were developed in the past years. They have been well documented by a steadily increasing number of publications and patents. Substituted imidazolidine-2-thiones and imidazole-2-thiones display remarkable biological activities. For instance, imidazole-2-thione has been reported to exhibit antimicrobial, antifungal, antithyroid, antioxidant, cardiotonic, antihypertensive, Dopamine beta-Hydroxylase (DBH) inhibitory and anti-HIV properties. Imidazolidine-2-thione derivatives have been reported to exhibit antimicrobial activity, anti-HIV activity, antifungal activity and so forth. The main purpose of this review is to present a survey of the literature on the different methods of synthesis and reactions involving imidazolidine-2-thione and imidazole-2-thione during the last few decades. This article summarizes an efficient, microwave-assisted method for the liquid-phase combinatorial synthesis of 3,5-disubstituted-thiohydantoin, also reported previously. Synthesis of metal complexes of imidazolidine-2-thione and its derivatives were reported as antimicrobial agents also discussed in the article. Some of the chiral imidazolidine-2-thione N-and C-nucleoside were reported as precursors for the synthesis of azidonucleosides and fluoronucleosides known for their anti-AIDS activity. Metal complexes of heterocyclic thione ligands were reported to possess antifungal activity. Imidazolidine-2-thione and imidazole-2-thione derivatives have found applications in diverse therapeutic areas. Imidazolidine-2-thiones are also used as a chiral auxiliary and ligand for asymmetric catalysis.

A red luminescent organic–inorganic hybrid network with double-stranded zigzag [Cu4I4]n chains

Abstract A novel red luminescent coordination polymer, [Cu2I2(bmt)]n·nDMF (1), was synthesized from the solution reaction of CuI and heterocyclic thione ligand, benz-1,3-imidazole-2-thione (bmt). Single-crystal analysis shows that its unusual organic–inorganic hybrid framework built-up from the distorted double-stranded zigzag [Cu4I4]n chains with organic bmt ligands. Emission properties of 1 in solid state at room temperature and 10 K were investigated.

A 2-D coordination polymer with Cu4 IS4-core as joints

A coordination polymer based on copper(I) and a heterocyclic thione ligand, HPPT4 (HPPT4 = 4-pyridin-4-yl-pyrimidine-2-thiol) has been prepared. The compound C21H19Cu2N7OS2 (1) has a 2-D polymeric structure with -core as joints linked by μ-thiolate bridges. Crystal data for compound 1: Monoclinic, space group C2/c, a = 22.346(14) Å, b = 15.649(10) Å, c = 13.588(9) Å, β = 97.183(12)°, V = 4714(5) Å3, and Z = 8. Compound 1 displays multiple emissions with maximum wavelength at 391 and 469 nm under photoexcitation at 340 nm.

Reactions of half-sandwich Co(III) complexes with heterocyclic thione ligands: η2-N, S coordination mode and formation of S–S bond

The reactions of Cp∗CoI2(CO) with heterocyclic thione ligands yields a η2-N, S coordination family of cobalt complexes for adjacent N, S donor atoms, and dinuclear disulfide cobalt complexes for opposite N, S donor atoms.

Cationic and neutral phenylmercury(II) complexes with heterocyclic thione ligands. X-ray structures of [HgPh(dmpymtH)][BF 4] · H 2O and [{HgPh} 2(μ-dtu)

The neutral complex [HgPh(dmpymt)] 1 (dmpymtH = 4,6-dimethylpyrimidine-2(1H)-thione) reacts with HBF 4 to give the cationic complex [HgPh(dmpymtH)][BF 4] 2. The X-ray molecular structure of the later revealed a [2+1] coordination sphere about the mercury(II) atom (C−Hg−S and Hg⋯N). In the dinuclear complex [(HgPh) 2(μ-dtu)] 3 [dtuH 2 = 2,4(1H,3H)-pyrimidinedithione or dithiouracil] the coordination spheres are also [2+1] although dissimilar regarding the Hg⋯N secondary bonds. NMR spectroscopy ( 1H, 13C and 199Hg) studies were undertaken in solution and the results discussed in the light of the X-ray structures.

Synthesis and characterization of mixed-metal complexes of Ag/Cu and W/Mo and a complex of Ag with heterocyclic thione ligands

Reactions of AgI with salts of [WS(4)](2-) or [MoS(4)](2-) and with either imidazolidine-2-thione (Imt) or [1,3]diazepane-2-thione (Diap) give the complexes [WS(4)Ag(2)(Imt)(2)](n) and [MS(4)Ag(2)(Diap)(4)] [M = W or Mo]; in the case of Diap, corresponding Cu complexes can be obtained with CuCl instead of AgI. Decomposition of the Ag-Diap complexes during attempted recrystallization leads to the polymeric complex [AgI(Diap)](n). The monomeric mixed-metal Diap complexes contain edge-sharing WS(4) and AgS(4) tetrahedra, the Diap ligands being terminally bonded to Ag through sulfur. The mixed-metal W-Ag-Imt complex is a chain polymer with two different environments for the WS(4) unit and three different coordination environments for Ag, one of which is an unprecedented AgS(5) square-based pyramid; Imt ligands are terminally coordinated to Ag. [AgI(Diap)](n) has a complex polymeric chain structure with three different distorted tetrahedral environments for Ag, direct Ag-Ag bonding, both bridging and terminal I, and all Diap ligands bridging pairs of Ag atoms. All the crystal structures feature N-H[...]S or N-H[...]I hydrogen bonding. The complexes have also been characterised by infrared, UV-Vis and (1)H and (13)C NMR spectroscopy.

Copper(I) halide chelates of the wide bite angle diphosphane xantphos: Crystal structures of [CuBr(xantphos)(dmpymtH)] and [CuI(xantphos)(imdtH 2)] · CH 3CN

Copper(I) halide complexes containing the diphosphane xantphos (4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene) and some heterocyclic thione ligands have been synthesized and characterized by 1H NMR, IR spectroscopy, elemental analyses and melting point determinations. The complexes can be readily obtained by the addition of the thione ligand to a CuX-diphosphane adduct in acetonitrile/methanol solution. The molecular structures of [CuBr(xantphos)(dmpymtH)] and [CuI(xantphos)(imdtH 2)] · CH 3CN have been established by single-crystal X-ray diffraction. Each of these structures features a tetrahedral copper(I) center with two phosphorus atoms from the chelating diphos ligand, one halogen atom and the exocyclic sulfur atom of the heterocyclic thioamide unit. Rapid decomposition of the mixed-ligand complexes via ligand dissociation occurs upon standing of their acetonitrile solutions at room temperature for several days. The resulting colored crystals, which not only on elemental analysis but also on the basis of their NMR and IR spectra, are found to be phosphane-free coordination polymers of composition [CuX(thione)].

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.

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.

Synthesis and characterization of copper(I) complexes with triphenylphosphine and heterocyclic thione ligands: the crystal structure of (thiazolidine-2-thione)(bis-triphenylphosphine) copper(I) chloride

Reactions of [Cu(PPh 3) 3Cl] with heterocyclic thiones (L) (L = pyridine-2-thione (py2SH), 1,3-thiazolidine-2-thione (tzdtH), benz-1,3-imidazoline-2-thione (bzimtH 2), bens-1,3,-thiazoline-2-thione (bzimtH), 4,5-diphenyl-imidazol-2-thione (dpimtH), 3-methylbenz-1,3-thiazoline-2-thione (mbztztH), 6-ethoxybenz-1,3-thiazoline-2-thione (etbztztH). 4-hydroxy-5-methyl-pyridine-2-thione (hympmtH), 4,6-dimethyl-pyrimidine-2-thione (dmpmtH), 4-mercapto-1H-pyrazolo[3,4 d] pyrimidine (pyrpmtH) and quinoline-2-thione (quintH)) yield mononuclear complexes of the general formula [Cu(PPh 3) 2(L)Cl]. The complexes were characterized by various physicochemical methods. The crystal structure of [Cu(PPh 3) 2(tzdtH)Cl] was determined by single-crystal X-ray diffraction methods. The yellow crystals are monoclinic, space group P2 1/c with a = 14.31(2), b = 10.099(10), c = 24.52(2) A ̊ , β = 93.53(7)° and Z = 4 . The copper atom has a pseudotetrahedral geometry with the bond lengths CuS = 2.418(5), CuCl = 2.344(3), CuP(1) = 2.287(3) and CuP(2) = 2.298(2) A ̊ . The structure was solved by direct methods with a final R value of 0.0562.

Silver(I) complexes with heterocyclic thiones and tertiary phosphines as ligands Part 2. Mononuclear complexes of silver(I) nitrate. The crystal structures of [Ag(PPh 3) 2(pytH) 2]NO 3 and [Ag(PPh 3) 2(pymtH)]NO 3

The preparation and characterization of mononuclear silver(I) nitrate complexes with various heterocyclic thiones (pytH = pyridine-2-thione, pymtH = pyridine-2-thione, quin2tH = quinoline-2-thione, izdtH = thiazolidine-2-thione, mbzimtH 2 = N=methyl-benzimidazoline-2thione, pur6tH = purine-6-thione) and triphenylphosphine as ligands are described. The X-ray determination of the crystal structures of [Ag(PPh 3) 2(pytH) 2]NO 3 ( I) and [Ag(PPh 3) 2(pymtH)]NO 3 ( II) is also reported. Compound I crystallizes in the monoclinic system, space group P2 1/ c, with a = 12.588(3), b = 18.234(5), c = 18.527(5) A ̊ , β = 96.29(2)°, V = 4227 A ̊ 3 and Z = 4 , while crystals of II are triclinic, space group P 1 , with a = 10.084(2), b = 13.508(3), c = 14.326(3) A ̊ , α = 77.43(2), β = 78.14(2)°, V = 1646 A ̊ 3 and Z = 2 . The coordination geometry about the silver atom is distorted tetrahedral in I, with one nitrate ion bridging two adjacent complex molecules via strong hydrogen bonds with the thione NH groups. The structure of II consists of almost trigonal-planar AgP 2S units and strongly distorted nitrate ions hydrogen bonded to the protonated nitrogen atoms of the heterocyclic thione ligands. The electronic factors imposing the above difference in coordinating behavior are investigated by means of semi-empirical molecular orbital considerations.

Four-coordinate copper(I) iodide complexes with triphenylphosphine and heterocyclic thione ligands. The crystal structure of [Cu(PPh 3) 2(pymtH)I

[Cu(PPh 3)I] 4 reacts with heterocyclic thiones (L) [L = pyrimidine-2-thione (pymtH), 1,3-thiazoline-2-thione (tzdtH), 1,3-imidazoline-2-thione (imtH), benz-1,3-imidazoline-2-thione (bzimtH 2) and benz-1,3-thiazoline-2-thione (bztztH)] in the presence of triphenylphosphine to give mononuclear complexes of the general formula [Cu(PPh 3) 2 (L)I]. These complexes have been characterized by various physicochemical methods. The crystal structure of [Cu(PPh 3) 2(pymtH)I] has been determined by single-crystal X-ray diffraction methods. The molecule is mononuclear, with a distorted tetrahedral geometry and bond lengths CuS = 2.338(4), CuI = 2.674(2), CuP = 2.296(4) and 2.303(4) Å.

Copper(I) complexes with tri-o-tolylphosphine and heterocyclic thione ligands. Crystal structures of [(pyrimidine-2-thione)(tri-o-tolylphosphine)copper(I) chloride] and [(pyridine-2-thione)(tri-o-tolylphosphine)copper(I) iodide

Copper(I) complexes of the general formula [Cu(totp)(L)X], where X = Cl, I; totp = tri-ortho-tolylphosphine; L = pyridine-2-thione (py2SH), pyrimidine-2-thione (pymtH), 1,3-thiazolidine-2-thione (tzdtH), 1-methyl-1,3-imidazole -2-thione (meimtH), benz-l,3-imidazoline-2-thione (bzimtH2) and quinoline-2-thione (qntH) were prepared and characterized by their IR, UV-Vis and 1H NMR spectroscopic data. The behaviour of the complexes upon photolysis in chloroform solutions has been investigated. The structures of [Cu(totp)(pymtH)Cl] and [Cu(totp)(tzdtH)I] were determined by X-ray diffraction: [Cu(totp)(pymtH)Cl] crystallizes in the trigonal space group P3 with a = 22.433(4), b = 22.433(4), c = 9.526(3) Å, γ=120° and Z = 6; [Cu(tzdtH)(totp)I] crystallizes in the monoclinic space group P21/n with a = 17.111(2), b = 10.505(1), c = 14.823(1) Å, β = 108.30(1)°, Z = 4. In both complexes the coordination around Cu is approximately trigonal planar. Steric protection at the central metal by the three methyl groups neighbouring the donor phosphorus of the phosphine ligand is likely to explain the preferential formation of three-coordinate complexes.

Computational study of heterocyclic thione ligands. Part I. Five-membered heteroatomic thiones possessing an α-nitrogen heteroatom

A SCF-MNDO study is made of the equilibrium between the "thiol" and "thione" tautomers of four species possessing a five-membered heterocyclic ring, where nitrogen and oxygen or sulfur are the α-heteroatoms. Based on the computationally derived Δ(ΔHf) values for each pair of forms, evidence is presented for the possibility of co-occurrence of the two forms in solution. The tautomerism is particularly interesting in this class of compounds, since it offers the possibility for a sulfur, nitrogen, or sulfur and nitrogen coordination. The nucleophilicity of each specific site in both forms is discussed in terms of net atomic charges and the HOMO constitution of the molecules. Results concerning the study of metal complexes are generally in accordance with these considerations, since the preference for a specific donation scheme is governed by an HSAB criterion.