Carbon Dioxide Fixation with Dialkyltellurium(IV) Dihydroxides

Aqueous solutions of Me₂Te(OH)₂ and (CH₂)₄Te(OH)₂ readily absorb carbon dioxide giving rise to the formation of the dialkyltelluroxane carbonates (Me₂TeOTeMe₂CO₃)_n ( 1 ) and HO(CH₂)₄TeOTe(CH₂)₄CO₃Te(CH₂)₄OH·2H₂O ( 2 ·2H₂O), which were characterised by ¹³C MAS and ¹²⁵Te MAS NMR spectroscopy as well as X‐ray crystallography. The spatial arrangement of the tellurium atoms is defined by C₂O₂ donor sets in the primary coordination sphere and one or two secondary Te···O contacts, which involve coordination of the carbonate moieties. In turn, the different Te–O coordination modes render a lack of symmetry to the carbonate moieties, which show significantly different C–O bond lengths, an important feature when contemplating the C–O bond activation in carbonates. The structural and spectroscopic parameters of 1 and 2 are discussed in comparison with other heavy p‐block element carbonates. In solution, electrolytic dissociation of 1 and 2 takes place.     

Supramolecular Assembling of Complex Tellurium Salts: Synthesis and Crystal Structures of {Cs[PhTeCl4]·CH3OH} and Cs[PhTeBr4]

The direct reaction between PhTeCl₃ and CsCl in methanol affords {Cs[PhTeCl₄]·CH₃OH}. Cs[PhTeBr₄] was prepared by refluxing [2‐Br‐C₅NH₅][PhTeBr₄] and CsCl in ethanol in the presence of an excess of HBr. In {Cs[PhTeCl₄]·CH₃OH} the [PhTeCl₄]^— units form dimers by secondary Te···Cl bonds with methanol molecules bridging adjacent Cs⁺ cations. In both compounds, the alkali metal cation interacts secondarily with the chlorine and bromine Te‐ligands, achieving singular coordination polyhedrons and holding the lattices in supramolecular tridimensional assemblies. The new complexes, {Cs[PhTeCl₄]·CH₃OH} and Cs[PhTeBr₄], crystallize in the space groups P2₁/c and P2₁/n, respectively. Only one such structure has been reported before.     

Supramolecular Assembling through Anionic Iodine Secondary Bonds: Synthesis and X‐ray Characterization of (Et4N)[PhTeI4] and (Et4N)[(β‐Naphthyl)TeI4]

[PhTe]₂ and [(β‐naphthyl)Te]₂ react with iodine and tetraethylammonium iodide in toluene/methanol to give (Et₄N)[PhTeI₄] and (Et₄N)[(β‐Naphthyl)TeI₄]. The complexes were analysed by single crystal X‐ray diffraction affording the centrosymmetric monoclinic space group P2₁/c. In the novel compounds only anionic interactions of the types Te···I and I···I take place, cation‐anion effective contacts do not occur. Both anions [PhTeI₄] and [(β‐naphthyl)TeI₄] exhibit square pyramidal coordination at tellurium, with the iodine atoms in the basal positions and the organic groups apical. The tellurium centers achieve an octahedral coordination in the whole lattices through Te···I secondary bonds with the adjacent ionic species. Only the Te–I‐ and I–I‐secondary bonds behave as structure‐forming interactions in the self‐organization of the supramolecular anionic gatherings. New evidences show that for organyltellurates (Q)[PhTeX₄] (Q = protonated amines, amides or amino acids; X = Cl, Br, I), NH···X hydrogen bondings are able to hinder the anionic halogen‐halogen secondary interactions. In case of the more frequent I···I interactions, they have been observed only in the absence of NH···I hydrogen bonds.     

Kinetics and Mechanism of the Nucleophilic Substitution of Tellurium(II) Dialkanethiolates,Te(SR1)2 with Thiols,HSR2

The equilibrium reaction between tellurium(II) dithiolates and thiols, Te(SR¹)₂ + 2 HSR² ? Te(SR²)₂ + 2 HSR¹ was studied by means of ¹H- and ¹²⁵Te NMR spectroscopy and ab initio quantum chemical methods. It was found that the reaction is catalyzed by Brønsted acids and bases, the catalytic activity corresponding to the strength of the respective acid or base. Investigation of the initial step of the reaction, Te(SR¹)₂ + HSR² ? Te(SR¹)(SR²) + HSR¹, showed it to proceed according to first order kinetics for Te(SR¹)₂, HSR² and for the catalyst. Ab initio geometry optimizations and frequency calculations suggest [Te(SR¹)(HSR¹)(HSR²)]⁺ and [Te(SR¹)₂(SR²)]^? to be stable intermediates and not transition states in the acid and base catalyzed reactions, respectively. The reaction hence proceeds via an additional elimination rather than an S _N 2 mechanism. The catalytic activity displayed by acids and bases can be applied to reduce the temperature in synthesis of thermally labile tellurium(II) dithiolates.     

Functionalized Organotellurium Halides: Synthesis,Characterization, and Observation of Intra- and Intermolecular Secondary Bonding

Abstract

Activated tellurium, but not selenium, reacts with para-substituted benzoylmethyl bromides as well as with iodoacetamide at their melting points in absence of a solvent to give bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC₆H₄COCH₂)₂TeBr₂, (Y = H, Me, and MeO) and bis(acetamido)tellurium diiodide, (H₂NCOCH₂)₂TeI₂, respectively. Quick reduction of (p-YC₆H₄COCH₂)₂TeBr₂, with sodium metabisulphite in a two-phase system yields crystalline (p-YC₆H₄COCH₂)₂Te. These tellurides undergo smooth oxidative addition of halogens, interhalogen ICl or a pseudohalogen (SCN)₂. Intramolecular coordination of the carbonyl group in these functionalized diorganotellurium dihalides is evident from IR spectra and shorter Te···O (carbonyl) distances in comparison to the sum of van der Waals radii and completes six coordination around Te atom. Not unexpectedly, therefore, intermolecular secondary bonding effects of the type Te…O, Te···X and X···X are missing in (PhCOCH₂)₂TeBr₂, (p-MeOC₆H₄COCH₂)TeBr₂ and (PhCOCH₂)₂TeI₂. Instead, these compounds provide rare examples, among organotellurium compounds, of supramolecular architecture, where C–H···Br and C–H···O hydrogen bonds and π-π (phenyl ring) interactions appear to be the noncovalent intermolecular associative forces that dominate the crystal packing.     

Synthese und Kristallstrukturen von (PPh4)2[TeS3] · 2 CH3CN und (PPh4)2[Te(S5)2]

Synthesis and Crystal Structures of (PPh₄)₂[TeS₃] · 2 CH₃CN and (PPh₄)₂[Te(S₅)₂] (PPh₄)₂[TeS₃] · 2 CH₃CN was obtained by the reaction of PPh₄Cl, Na₂S₄ and Te in acetonitrile. With sulfur it reacts yielding (PPh₄)₂[Te(S₅)₂]. The crystal structures of both products were determined by X-ray diffraction. (PPh₄)₂[TeS₃] · 2 CH₃CN: triclinic, space group P1 , Z = 2, R = 0.041 for 4 629 reflexions; it contains trigonal-pyramidal [TeS₃]^2? ions with an average Te? S bond length of 233 pm. (PPh₃)₂[Te(S₅)₂]: monoclinic, P2₁/n, Z = 2, R = 0.037 for 2 341 reflexions. In the [Te(S₅)₂]^2? ion the tellurium atom has a nearly square coordination by four S atoms. Along with the Te atoms each of the two S₅ groups forms a ring with chair conformation.     

Synthesis,Structural Characterization and Reactivity of Two New Triangular Molybdenum Cluster Compounds：Mo3T37—[S2CN（CH2CH2OH）2]3I and Mo3Te4Y3[S2P（^iPrO）2]3I（Y3=1.43Te＋1.57S）

Two triangular molybdenum‐tellurium clusters, Mo₃Te₇‐[S₂CN (CH₂CH₂OH₂]₃I (1) and Mo₃Te₄Y₃[S₂P(ⁱPrO)₂]₃I (Y₃ = 1. 43Te+ 1.57S) (2), were obtained from the reaction of K · HOdtc [HOdtc = S₂CN(CH₂CH₂OH)₂] or K·ⁱPr₂dtp (ⁱPr₂dtp = S₂P[OCH(CH₃)₂]₂) with a mixed product of elements Mo, Te(S) and I₂ at high temperature. The structures of the two compounds were determined by X‐ray crystallography study. Crystal data are, (1): monoclinic, P2₁/n, a = 1.6256(3), b = 1.3264(2), c = 1.8808(4) nm, β=96.923°, V = 4.025.9 (14) nm³, D_cal = 3.050g·cm‐³, Z = 4, and (2): monoclinic, P2₁/n, a = 1.4564(2), b = 2.3917(4), c = 1.5094(3) nm, β = 114.35(2)°, V = 4.0259(14) nm³, D_cal = 2.449 g·cm^?3 and Z = 4. Single crystal analyses show that 1 consists of discrete Mo₃Te₇[S₂CN(CH₂CH₂OH)₂]₃I connected into three‐dimensional framework via hydrogen bonds, while 2 forms a linear chain via Te(S)—I interaction.     

The Simultaneous Oxidation of Tellurium and Transition Metals by AsF5 – Syntheses and Crystal Structures of [M(SO2)6](Te6)[AsF6]6 (M = Ni,Zn) and [Cd(SO2)2][AsF6]2

The reactions of elemental nickel and tellurium and of ZnTe with excess AsF₅ in liquid SO₂ yield [M(SO₂)₆](Te₆)[AsF₆]₆ (M = Ni, Zn) as orange crystals. The crystal structure determinations (triclinic, , M = Ni: a = 1632.59(2), b = 1795.06(1), c = 1822.97(2) pm, α = 119.11(4), β = 90.78(4), γ = 106.28(4)°, V = 4408.24(8)·10⁶pm³, Z = 4) show the two compounds to be isotypic. The structures are made up of discrete [M(SO₂)₆]²⁺ complexes, Te₆⁴⁺ clusters and octahedral [AsF₆]^? ions. In the [M(SO₂)₆]²⁺ complexes the metal ions are surrounded octahedrally by six SO₂ molecules bound via the O atoms. The Te₆⁴⁺ polycations are of trigonal prismatic shape with short Te–Te bonds within the triangular faces (270 pm) and long Te–Te bonds along the edges parallel to the pseudo C₃ axes of the prisms (312 pm). The arrangement of the ions is related to the Li₃Bi structure type. [M(SO₂)₆]²⁺ complexes and Te₆⁴⁺ polycations together form a distorted cubic closest packing with all tetrahedral and octahedral interstices filled by [AsF₆]^? ions. The analogous reaction starting from CdTe did not yield a compound containing simultaneously [Cd(SO₂)_n]²⁺ complexes and tellurium polycations but instead Te₆[AsF₆]₄ · 2 SO₂ besides [Cd(SO₂)₂][AsF₆]₂ were obtained. It crystallizes isotypically to [Mn(SO₂)₂][AsF₆]₂ (Mews, Zemva, 2001) (orthorhombic, Fdd2, a = 1534.96(3), b = 1812.89(3), c = 892.28(3) pm, V = 2483·10⁶ pm³, Z = 4).     

Twinning by merohedry in bis(4‐methoxyphenyl)tellurium(IV) diiodide dimethyl sulfoxide hemisolvate

Green crystals of the title compound, C₁₄H₁₄I₂O₂Te·0.5C₂H₆OS, space group P3₂, show twinning by merohedry (class II). The asymmetric unit contains two organotellurium molecules and one dimethyl sulfoxide (DMSO) molecule. The crystal structure displays secondary Te...I and Te...O(DMSO) bonds that lead to [(4‐MeOC₆H₄)₂TeI₂]₂·DMSO supramolecular units in which the two independent organotellurium molecules are bridged by the DMSO O atom. In addition to these secondary bonds, I...I interactions link translationally equivalent organotellurium molecules to form nearly linear ...I—Te—I...I—Te—I... chains. These chains are crosslinked, forming two‐dimensional arrays parallel to (001). The crystal packing consists of a stacking of these sheets, which are related by the 3₂ axis. This study describes an unusual dimeric arrangement of X—Te—X groups.     

Dimerization of New T‐shaped Hypervalent Organotellurium(II) Dihalides: Synthesis and Structural Characterization of (PyH)[mesTeIX] (Py = pyridine; mes = mesityl; X = Cl,Br, I)

[mesTe]₂ reacts with iodine in toluene and further with (C₅H₆N)⁺X^? (X = I, Br, Cl) to give (PyH)[mesTeI₂] ( 1 ), (PyH)[mesTeIBr] ( 2 ) and (PyH)[mesTeICl] ( 3 ). The anionic fragments [(mes)TeI₂] and [(mes)TeIBr] of 1 and 2 are assembled as dimers by reciprocal, secondary Te···X interactions, linked also to the pyridinium cations through μ‐NH···X bonding. The anion [(mes)TeICl]^? ( 3 ) do not interact with neighboring anionic moieties, achieving also secondary NH···Cl bonding toward the pyridinium cation. The dimerization ability – with attaining of additional interionic hydrogen bridges – of 1 and 2 allow them to be viewed as partially “molecular” and as hypervalent compounds of Te^II, for which the observed linearity of the I–Te–X system and the similarity of the Te–X bond distances are expected.     

Synthesis and Crystal Structures of Neutral Complexes of Tellurium(IV) – [PhTeX3L](X = Br,I; L = ethylenethiourea)

A three‐step one‐pot synthetic procedure to synthesize the neutral tellurium(IV) coordination compounds PhTeX₃L (X = Br, I and L = ethylenethiourea) has been developed and is described in this article. Oxidative halogenation of PhTeTePh in methanol generates the tellurium(II) derivative, PhTeX, which is subsequently complexed with ethylenethiourea, and, finally, further oxidative addition of additional halogen affords the corresponding tellurium(IV) compound PhTeX₃L in good yields. The final product was obtained by the slow evaporation of the reaction mixture as black crystals. The X‐ray structural analyses of the compounds show Te···X and X···X secondary interactions in the solid state and suggest a weak dependence of the formation of supramolecular assemblies on the nature of the halogen bonded to the tellurium atom.     

Syntheses and Structures of Four New Tellurium(II) Complexes

The four Te^II complexes, cis‐[TeCl₂{(ⁱPrNH)₂CS}₂] ( 1 ), cis‐[TeCl₂{(ⁱBuNH)₂CS}₂] ( 2 ), trans‐[TeCl₂{(PhNMe)₂CS}₂] ( 3 ), and trans‐[TeCl₂{(Et₂N)₂CS}₂] ( 4 ), have been synthesised and their molecular structures solved by means of X‐ray crystallography. All four complexes are square planar, those with disubstituted thiourea ligands have a cis configuration, those with tetrasubstituted thioureas have a trans configuration. The Te–S bond lengths in 1 and 2 average 2.4994 and 2.5213 Å, respectively. The Te–Cl bonds trans to the Te–S bonds have average lengths of 2.8754 and 2.8334 Å, reflecting the trans influence of the two disubstituted thioureas. In 3 and 4 with identical ligands trans to each other, the average Te–S and Te–Cl bond lengths are 2.6834 and 2.5964 Å, respectively.     

Modification of supramolecular assemblies based on C4H7(CH3)Te heterocycle and cooperative participation of intermolecular I···I, Te···I, Te···O secondary bonds; C(sp3)–H···O and C(sp2)–H···O hydrogen bonds

2-Methyl-1,1-dicarboxylato-1-telluracyclopentanes C₄H₇(CH₃)Te(OCOR)₂ (R=OCO, C₆H₅, 4-NO₂C₆H₄, 3,5-(NO₂)₂C₆H₃, C₆H₅CH=CH, 4-OCH₃C₆H₄) (2–7) were synthesised from the reactions of 2-methyl-1,1-diiodo-1-telluracyclopentane (1) and corresponding silver salts and characterised by (IR &¹HNMR) spectroscopy. The structures of C₄H₇(CH₃)TeI₂ (1), C₄H₇(CH₃)Te(OCOC₆H₅)₂ (3) and C₄H₇(CH₃)Te(4-NO₂C₆H₄OCO)₂ (4) were established by single crystal X-ray diffraction studies. The structures of 1, 3 & 4 (the immediate environment about tellurium is that of distorted trigonal bipyramidal geometry with a stereochemically active electron lone pair) are described in the context of their ability to generate intermolecular I···I, Te···I, Te···O secondary bonds; C(sp³)–H···O and C(sp²)–H···O hydrogen bonds leading to the formation of polymeric, tetrameric and trimeric supramolecular assemblies. The modification of supramolecular assembly present in the precursor 1 is demonstrated and the cooperative participation of C(sp²)–H···O & C(sp³)–H···O hydrogen bonds, probably, helpful in strengthening the supramolecular assembly is discussed.

(O,O′)-Diorganodithiophosphatophenyltellur(II)- und Tris[(O,O′)-diorganodithiophosphato]phenyltellur(IV)-Verbindungen; Kristallstruktur von Tris[(O,O′)-diphenyldithiophosphato]phenyltellur(IV)

(O,O′)-Diorganodithiophosphatophenyltellurium(II)- and Tris[(O,O′)-diorganodithiophosphato]phenyltellurium(IV) Compounds; Crystal Structure of Tris[(O,O′)-diphenyldithiophosphato]phenyltellur(IV) The title compounds are available by reaction of trichlorophenyltellurium(IV) respectively iodophenyltellurium(II) with the sodium or ammonium salts of (O,O′)-diorganodithiophosphorus acids in various solvents. The resulting tellurium(IV) compounds have a pronounced tendency towards reductive elimination of bis[(O,O′)-diorganothiophosphoryl]disulfanes [S₂P(OR)₂]₂ in solution. In contrast, the tellurium(II) compounds are stable, although they are disintegrated to diphenylditellane and [S₂P(OR)₂]₂ on prolonged standing in chlorinated hydrocarbons. Crystals of tris[(O,O′)-diphenyldithiophosphato]phenyltellurium(IV) are monoclinic (space group P2₁/c) with the cell constants: a = 1 039.2(1), b = 1 037.9(3), c = 4 205.0(1) pm, β = 95.273(1)°, V = 4 516.42(9)X10⁶ pm³, Z = 4. The compound appears to be monomeric in the solid state forming a distorted pentagonal bipyramid. The stereochemical influence of the lone pair of electrons causes the axial (i. e. C1? Te? S4) angle to be 156.6(1)° rather than the theoretical 180°.     

Palladium(II) Chloride Interaction with Chelating BIS(Phosphine Sulfides). Effect of the Ligand Structure on the Complex Geometry

Abstract

Interaction of PdCl₂ in chloroform with bis(phosphine sulfides) Ph₂P(S)?X?P(S)Ph₂ (X?CH₂, C(CH₃)₂, CH₂CH₂, NH, S, and SCH₂S) has been studied. Mechanism of the reaction has been found to vary dramatically with the identity of X. The structures of the resultant complexes were evaluated by UV and IR spectroscopy. Crystal structures were were determined by X-ray diffraction for two of the compounds (A: [Ph₂P(S)?(CH₂)₂?P(S)Ph₂]PdCl₂ · CH₃CN, P2₁/n, Z = 4, a = 10.104(2), b = 20.939(4), c = 14.034(3) Å, γ = 102.54(2)· B: [Ph₂P(S)?N?P(S)Ph₂]₂Pd · 2CHCl₃, Pl, Z = 1, a = 9.539(1), b = 12.333(3), c = 12.866 Å, α = 111.83(2)°, β = 96.70(3)° γ = 99.84(3)°).     

Synthesis and Structural Characterization of a Novel Indium Mercapto Derivative [ClIn(SCH2(CO)O)2]2-[(4-MepyH)2]2+

The synthesis and structural characterization of a novel In(III) complex is described. The reaction between InCl₃ with sodium mercapto-acetic acid (NaSCH₂(CO)OH) in 4-methylpyridine (CH₃(C₅H₅N), (4-Mepy)) at 25°C affords [ClIn(SCH₂(CO)O)₂]^2-[(4-MepyH)₂]²⁺ (1). X-ray diffraction studies of (1) show it to have a distorted square-pyramidal geometry with the [(^-SCH₂(CO)CO^-)] ligands in a trans conformation. The compound crystallizes in the P1(No. 2) space group with a = 7.8624(6) Å, b = 9.950(1) Å, c = 13.793(2) Å, α = 107.60(1)°, β = 90.336(8)°, γ = 98.983(9)°, V = 1014.3(4) ų, R(F°) = 0.037 and R_w = 0.048.     

The Photooxidation of Bis(8‐dimethylaminonaphthyl) Ditelluride

The photooxidation of (8‐Me₂NC₁₀H₆Te)₂ provided a complex reaction mixture from which the novel tetranuclear telluroxane cluster (8‐MeNC₁₀H₅TeO)₄ ( 1 ) was isolated in 17 % yield. Compound 1 contains two 5,5′‐binaphthyl moieties that presumably formed by oxidation of C5–H bonds of the naphthyl ring. Upon formation of 1 , one of the two methyl groups of the 8‐dimethylamino group was cleaved and the remaining coordinative Te···N bond turned into a covalent Te–N bond. In the solid‐state, individual molecules of 1 are associated through secondary Te···O interactions giving rise to a 1D coordination polymer.     

Crystal And Molecular Structure of Zinc DI-(4-Chlorphenylthioacetate) Dihydrate

Zinc di-(4-chlorphenylthioacetate) dihydrate (4-ClC₆H₄SCH₂COO)₂Zn·2H₂O (ZTD) is obtained in the reaction of protatrane 4-chlorphenylthioacetate 4-ClC₆H₄SCH₂COO_s-²·N⁺H(CH₂CH₂OH)₃ with zinc dichloride (ZnCl₂) in aqueous alcohol. X-ray diffraction is used to study the crystal structure of ZTD and compare it with related compounds. All intermolecular O…O contacts of the neighboring zinc polyhedra are short in ZTD molecules. Apparently, the short intermolecular O…O contacts cause distortions of the octahedral environment of the zinc atom.     

[Be3(μ3‐O)3(MeCN)6{Be(MeCN)3}3](I)6 – ein Berylliumkomplex mit Cyclo‐(Be3O3)‐Kern und sein Hydrolyseprodukt [Be(H2O)4](I)2·2MeCN

Single crystals of [Be₃(μ₃‐O)₃(MeCN)₆{Be(MeCN)₃}₃](I)₆·4CH₃CN ( 1 ·4CH₃CN) were obtained in low yield by the reaction of beryllium powder with iodine in acetonitrile suspension, which probably result from traces of beryllium oxide containing the applied beryllium metal. The compound 1 ·4CH₃CN forms moisture sensitive, colourless crystal needles, which were characterized by IR spectroscopy and X‐ray diffraction (Space group Pnma, Z = 4, lattice dimensions at 100(2) K: a = 2317.4(1), b = 2491.4(1), c = 1190.6(1) pm, R₁ = 0.0315). The hexaiodide complex cation 1 ⁶⁺consists of a cyclo‐Be₃O₃ core with slightly distorted chair conformation, stabilized by coordination of two acetonitrile ligands at each of the beryllium atoms and by a {Be(CH₃CN)₃}²⁺ cation at each of the oxygen atoms. This unique coordination behaviour results in coplanar OBe₃ units with short Be–O distances of 155.0 pm and 153.6 pm on average of bond lengths within the cyclo‐Be₃O₃ unit and of the peripheric BeO bonds, respectively. Exposure of compound 1 ·4CH₃CN to moist air leads to small orange crystal plates of [Be(H₂O)₄]I₂·2CH₃CN ( 3 ·2CH₃CN). According to the crystal structure determination (Space group C2/c, Z = 4, lattice dimensions at 100(2) K: a = 1220.7(1), b = 735.0(1), c = 1608.5(1) pm, β = 97.97(1)°, R₁ = 0.0394), all hydrogen atoms of the dication [Be(H₂O)₄]²⁺ are involved to form O–H ··· N and O–H ··· I hydrogen bonds with the acetonitrile molecules and the iodide ions, respectively. Quantum chemical calculations (B3LYP/6‐311+G**) at the model [Be₃(μ₃‐O)₃(HCN)₆{Be(HCN)₃}₃]⁶⁺ show that chair and boat conformation are stable and that the distorted chair conformation is stabilized by packing effects.     

Synthesis,and Structural Characterization of [{CH3(C5H4N)}Ga(SCH2(CO)O)2] −[(4-MepyH)]+, A Novel Ga(III) Five-Coordinate Complex

The synthesis and structural characterization of a novel ionic Ga(III) five-coordinate complex [{CH₃(C₅H₄N)}Ga(SCH₂(CO)O)₂]^?[(4-MepyH)]⁺, (4-Mepy=CH₃(C₅H₅N)) from the reaction between Ga₂Cl₄ with sodium mercapto-acetic acid in 4-methylpyridine is described. Under basic reaction conditions the mercapto ligand is found to behave as a 2e^? bidentate ligand. Single crystal X-ray diffraction studies show the complex to have a distorted square-pyramidal geometry with the [(^?SCH₂(CO)CO^?)] ligands trans. The compound crystallizes in the P2₁/c (No. 14) space group with a=7.7413(6)Å, b=16.744(2)Å, c=14.459(2)Å, V,=1987.1(6)&Aringsup3;, R(F, _o)=0.032 and R_W =0.038.