Isovalent and mixed-valent molybdenum complexes containing Mo(μ-E)(μ-S2)Mo (E = O, S) core units

The reactions of Tp^iPrMoO(SR)(NCMe) (Tp^iPr = hydrotris(3-isopropylpyrazolyl)borate) with propylene sulfide in toluene result in the formation of the diamagnetic, isovalent Mo(V) complex, [Tp^iPrMo^VO]₂(μ-S)(μ-S₂). This complex and its previously reported μ-oxo analog, [Tp^iPrMo^VO]₂(μ-O)(μ-S₂), react with cobaltocene to produce one-electron-reduced, mixed-valent complexes, [CoCp₂][{Tp^iPrMo^IV,VO}₂(μ-E)(μ-S₂)] (E = S or O, respectively). All complexes have been isolated and characterized by microanalysis, mass spectrometry, IR and ¹H NMR or EPR spectroscopies, and X-ray crystallography. Neutral [Tp^iPrMo^VO]₂(μ-S)(μ-S₂) exhibits a pseudo-C₂ symmetric structure, with distorted octahedral anti oxo-Mo(IV) centers coordinated by Tp^iPr and linked by μ-sulfido and μ-disulfido ligands. A similar structure is adopted by the anion in mixed-valent [CoCp₂][{Tp^iPrMo^IV,VO}₂(μ-S)(μ-S₂)]; this compound adopts a hexagonal, supramolecular structure with columns of tight ion-pairs with interactions, interconnected through weaker contacts to three neighboring columns. The structure contains large interstitial voids filled with lattice solvent molecules. EPR investigation of the mixed-valent complexes gave rise to unusually broad signals with no evident hyperfine splitting. The synthesis and characterization of a number of cis-dioxo-Mo(VI) precursors are also reported.     

A new hydrated phase of cobalt(II) oxalate: crystal structure, thermal behavior and magnetic properties of {[Co(μ-ox)(H2O)2] · 2H2O}n

A cobalt-oxalato complex of formula {[Co(μ-ox)(H₂O)₂] · 2H₂O}_n (1) (ox=oxalate dianion) has been prepared and characterized by X-ray diffraction analysis, thermoanalytical techniques and variable temperature susceptibility measurements. The compound crystallizes in the triclinic space group with cell parameters: a=6.627(1), b=8.715(2), c=11.106(2) Å, α=69.86(1), β=83.45(1), γ=72.33(1)°. Its crystal structure consists of crystallization water molecules and one-dimensional linear chains of [Co(H₂O)₂]²⁺ units linked by bis-bidentate oxalato ligands. These structural units are held together by an extensive network of hydrogen bonds. The magnetic properties show the occurrence of antiferromagnetic interactions between the metal centers.     

Cobalt complexes bridge with a (μ-X)(μ-carboxylato) unit (X = OH, N3): synthesis and structural studies

By using the hindered tris(pyrazolyl)borate ligand Tp^iPr2 (hydrotris(3,5-diisopropyl-1-pyrazolyl))borate, both mono- and binuclear complexes of cobalt [Tp^iPr2Co](X) (X = NO₃ and OBz) and [Tp^iPr2Co]₂(μ-X)(μ-OBz) (X = OH, N₃) were synthesized. The nitrato complex, [Tp^iPr2Co](NO₃) (1), which could be converted to (2), was prepared by reaction of KTp^iPr2 with hydrated Co(NO₃)₂ and its molecular structure was determined by X-ray crystallography. The dinuclear di(μ-hydroxo) complex, [Tp^iPr2Co]₂(μ-OH)₂ (2), which was obtained by treatment of 1 with aqueous NaOH, reacted with one equivalent of benzoic acid to give the (μ-benzoato)(μ-hydroxo) complex, [Tp^iPr2Co]₂(μ-OH)(μ-OBz) (3). X-ray crystallography shows the presence of both hydroxy and carboxylate group as bridging ligands and both cobalt metals are in five coordination environment in 3. The μ-azido complex, [Tp^iPr2Co]₂(μ-N₃)(μ-OBz) (5), was prepared by reaction of 3 with one equivalent of aqueous sodium azide. The spectroscopic studies suggested μ-1,1-bridging nature of group in this complex. The reaction of 2 with excess amount of benzoic acid resulted in the destruction of the bimetallic core to give the mononuclear carboxylato complex, [Tp^iPr2 Co](OBz) (4), which was characterized by X-ray crystallography.     

Oxidative nuclease activity of ferromagnetically coupled μ-hydroxo-μ-propionato copper(II) complexes [Cu3(L)2(μ-OH)2(μ-propionato)2] (L = N-(pyrid-2-ylmethyl)R-sulfonamidato, R = benzene, toluene, naphthalene)

Three doubly-bridged, trinuclear copper(II) compounds with hydroxo and carboxylato bridges, ^∞₁[Cu₃(L1)₂(μ-OH)₂(μ-propionato)₂](1), [Cu₃(L2)₂(μ-OH)₂(μ-propionato)₂(DMF)₂] (2) and ^∞₁{[Cu₃(L3)₂(μ-OH)₂(μ-propionato)₂]} [Cu₃(L3)₂(μ-OH)₂(μ-propionato)₂(DMF)₂]} (3) [HL1 = N-(pyrid-2-ylmethyl)benzenesulfonylamide, HL2 = N-(pyrid-2-ylmethyl)toluenesulfonylamide, HL3 = N-(pyrid-2-ylmethyl)naphthalenesulfonylamide], have been synthesized and characterized. 1 is built from [Cu₃(L1)₂(μ-OH)₂(μ-propionato)₂] clusters. Each unit contains three copper(II) with two different coordination environments: the terminal centers are square-base pyramidal whereas the central copper is square planar. 2 presents a similar square-base pyramidal geometry in the terminal centers, but the central copper is six-coordinate. 3 shows an unusual 1D coordination polymer comprised of two distinct building blocks: one similar to that found in 1 and the other similar to that found in 2. The magnetic susceptibility measurements (2-300 K) reveal a ferromagnetic interaction between the Cu(II) ions with J values of 76.0, 55.0, and 48.0 cm⁻¹ for 1, 2, and 3, respectively. Emission spectroscopy, thermal denaturation, viscosimetry and cyclic voltammetry show an interaction of the complexes with DNA through the sugar-phosphate backbone. All three Cu(II) complexes were found to be very efficient agents of plasmid DNA cleavage in the presence of ascorbato or mercaptopropionic acid. Both the kinetics and the mechanism of the cleavage reaction have also been examined.     

Spin crossover behavior of a one-dimensional polymeric-chain compound {[Fe(abpt)2(μ-Ni(CN)4)]·xH2O}n (x = 0.5 → 0): Synthesis, spectral, thermal and magnetic properties

A one-dimensional polymeric-chain iron(II)-nickel(II) cyanido-bridged complex of the composition {[Fe(abpt)₂(μ-Ni(CN)₄)]·0.5H₂O}_n (1·0.5H₂O), where abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4-triazole, was prepared and characterized by elemental and thermal analyses, FTIR and ⁵⁷Fe Mössbauer spectroscopies, and magnetic measurements. The incomplete spin crossover phenomenon was observed with approximately 12% of the frozen high-spin fraction at low temperatures and with the spin transition critical temperature above room temperature.     

Crystal and molecular structures of {Cu(μ-CCPh)(triphos)}2 [triphos = (PPh2CH2)3CMe]

The binuclear complex {Cu(μ-CCPh)(triphos)}₂ [triphos = (PPh₂CH₂)₃CMe] has been obtained from a reaction between {Cu(CCPh)}_n and triphos. The two copper atoms are bridged unsymmetrically by two CCPh groups, each attached through one carbon only [Cu-C, 2.016(4) Å], the separation between the two coppers being 2.4663(8) Å. Only two of the three phosphorus atoms in each ligand are coordinated to copper [Cu-P(1,2) 2.281, 2.273(1) Å]. The observed structure may be rationalised using a recent theoretical study [C. Mealli, S.S.M.C. Godinho, M.J. Calhorda, Organometallics 20 (2001) 1734] and differs from that assumed for the rationalisation of its luminescence properties [V. Pawlowski, G. Knör, C. Lennartz, A. Vogler, Eur. J. Inorg. Chem. (2005) 3167].     

Dithiolate and diselenolate complexes [Pt2(μ-ECH2CHCHCH2E)(PPh3)4] (E = S, Se): Synthesis, characterisation and mass spectrometric formation of the dichalcogenide species [Pt2(μ-E2)(PPh3)4]

The reactions of [Pt₂(μ-E)₂(PPh₃)₄] (E = S, Se) with cis-1,4-dichlorobut-2-ene (cis-ClCH₂CHCHCH₂Cl) give the dichalcogenolate complexes [Pt₂(μ-ECH₂CHCHCH₂E)(PPh₃)₄]²⁺; an X-ray structure determination on the thiolate complex was carried out. The complexes give the expected dications in ESI mass spectra recorded at very low cone voltages, but at moderate cone voltages undergo facile fragmentation via a retro-Diels-Alder reaction and loss of 1,3-butadiene, giving the dichalcogenide species [Pt₂(μ-E₂)(PPh₃)₄]²⁺. Analogous species containing bidentate phosphine or arsine ligands have been previously generated electrochemically, and studied theoretically.     

4′-(4-Pyridyl)-2,2′:6′,2″-terpyridine as ligand in the lead(II) complexes, [Pb(pyterpy)(MeOH)I2] · MeOH and [Pb(pyterpy)(μ-AcO)]2(ClO4)2

Two new lead(II) complexes with the ligand 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine (pyterpy), [Pb(pyterpy)(MeOH)I₂] · MeOH and [Pb(pyterpy)(μ-AcO)]₂(ClO₄)₂, have been synthesized and characterized by CHN elemental analysis, ¹H NMR-, ¹³C NMR-, IR spectroscopy and structurally analyzed by X-ray single-crystal diffraction. The thermal stabilities of these compounds were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The single crystal X-ray analyses show that the coordination number in these complexes is six with three “pyterpy” N-donor atoms and two or three of the anionic ligands. The arrangement of donor atoms in these complexes suggest a gap or hole in the coordination geometry of the lead atoms, possibly occupied by a stereoactive lone pair of electrons on lead(II) and the coordination sphere is hemidirected. The potentially tetradentate ligand 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine (pyterpy) acts as a tridentate donor to Pb(II). The noncoordinated pyridyl group interacts with hydrogen atoms of adjacent molecules and forms normal hydrogen bonds in [Pb(pyterpy)(MeOH)I₂] · MeOH and weak C-H?N interactions for [Pb(pyterpy)(μ-AcO)]₂(ClO₄)₂, thus extending the monomeric structures into one-dimensional networks.     

Hyponitrite complexes: Crystal and molecular structure of [Ru2(CO)4(μ-PBu2)(μ-Ph2PCH2PPh2)(μ-η-ONNOMe)]

The new trans-hyponitrite derivative complex [Ru₂(CO)₄(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)] (2, dppm = Ph₂PCH₂PPh₂) was prepared by deprotonation of [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)][BF₄] (1) with the base DBU (1.8-diazabicyclo[5.4.0]undec-7-ene). The latter complex salt has been obtained in an improved synthesis starting from the trans-hyponitrite complex [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNO)]. Compound 2 has been characterized by spectroscopic methods as well as by X-ray diffraction and represents the first neutral complex bearing a deprotonated monoester of the hyponitrous acid as the bridging ligand.     

Succinate bridged dimeric Cu(II) system containing sandwiched non-coordinating succinate dianion: Crystal structure, spectroscopic and thermal studies of [(phen)2Cu(μ-L)Cu(phen)2]L · 12.5H2O (H2L = succinic acid; phen = 1,10-phenanthroline)

A mixed ligand and dimeric Cu^II complex [(phen)₂Cu(μ-L)Cu(phen)₂]L · 12.5H₂O (H₂L = succinic acid) containing bridging succinate moiety and also non-coordinated succinate dianion was prepared from polymeric Cu(II) succinate by nucleophilic reaction with o-phenanthroline (phen) followed by depolymerization. The dimeric product was characterized by crystallographic, spectroscopic and thermoanalytical studies. The complex crystallizes in triclinic crystal system and is composed of succinate bridged [(phen)₂Cu(μ-L)Cu(phen)₂]²⁺ complex cations, non-coordinated succinate anions and hydrogen bonded water molecules. Within the dimeric cationic unit, each of the Cu atoms is octahedrally coordinated by four N atoms of both phen ligands and both O atoms of a carboxylate moiety of the bridging succinate group in chelating form. Through intermolecular π-π stacking interactions, the complex cations form positively charged 2-D layers, between which the non-coordinating succinate anions and water molecules are sandwiched. Both the electronic and EPR studies indicate that the dimeric complex undergoes partial dissociation in solution state to exist in two structural forms. The kinetic and thermodynamic parameters involved in three stage thermal decompositions of the dimeric complex could also be evaluated using Coats-Redfern method.     

Molecular structure of tetranuclear [{Mo2O(S2CNEt2)(η-O2CCF3)(μ-N-o-tol)2}2(μ-O)(μ-O2CCF3)2] formed upon addition of trifluoroacetic acid to syn-[MoO(μ-N-o-tol)(S2CNEt2)]2

Addition of trifluoroacetic acid to syn-[MoO(μ-N-o-tol)(S₂CNEt₂)]₂ in chloroform affords tetranuclear [{Mo₂O(S₂CNEt₂)(η¹-O₂CCF₃)(μ-N-o-tol)₂}₂(μ-O)(μ-O₂CCF₃)₂] which has been crystallographically characterised. It consists of four molybdenum(V) centres linked via bridging imido, trifluoroacetate and oxo ligands and results from replacement of a dithiocarbamate by two trifluoroacetate ligands.     

A family of lanthanide-containing molecular open frameworks with high porosity: [Ln(abdc)(Habdc), nH2O]∞ with Ln = La-Eu and 8 ? n ? 11

Reactions in water between the di-sodium salt of amino terepthalic acid (C₈H₃NO₄Na₂) and a lanthanide chloride lead to a family of 3D-coordination polymers with general chemical formula [Ln(C₈H₃NO₄)(C₈H₄NO₄), O]_∞ where Ln = La-Eu (except Pm) and 8 ? n ? 11. All these compounds are isostructural. High quality single crystals of [Ln(C₈H₃NO₄)(C₈H₄NO₄), nH₂O]_∞ with Ln = La-Sm (except Pm) and 8 ? n ? 11 have been obtained by slow diffusion in agar-agar gels. The crystal structure has been solved for the Nd-containing compound. This compound crystallizes in the cubic system, space group Ia-3 (no. 206) with a = 26.8056(5) Å. The crystal structure can be described as the juxtaposition of large channels with square cross-section.The channels are filled by highly disordered crystallization water molecules. The dehydration of the compounds by freeze-drying is possible and most of the crystallization water molecules can be removed without destruction of the molecular skeleton. The partially dehydrated compounds have general chemical formula [Ln(abdc)(Habdc), 2H₂O]_∞ with Ln = La-Eu except Pm. The porosity of the Nd-containing compound has been estimated by computational methods to 2170 m² g⁻¹. This dehydrated compound reversibly binds water when exposed to wet atmosphere restoring the initial hydrated phase.     

μ- and μ4-η coordination of A2H2 (A = C, Si, Ge, Sn and Pb) ligands with transition metals

The heavier analogs of C₂H₂ have been studied at the B3LYP level for their μ and μ₄-η² coordination properties with the transition metals. Based on known alkyne compounds, transition metal fragments [W₂(μ-NH)(Cp)₂(Cl)₂] and [Fe₄(CO)₁₂] have been chosen. The SBKJC relativistic effective core potentials and their associated basis sets were used on W, Fe, Sn and Pb, and the 6-31G(d) basis set was used on all other elements. All the complexes of Si₂H₂, Ge₂H₂, Sn₂H₂ and Pb₂H₂ are found to be local minima. The trans-twist nature of the ligand A₂H₂ (A = Si-Pb) is large in μ-coordinated complexes of W, and it is very small in μ₄-η² coordinated complexes of Fe. The electronic structure of these complexes was investigated using fragment molecular orbital method (FMO).     

Synthesis, crystal structures, and spectroscopic characterization of the neutral monomeric tetrahedral [M(Diap)2(OAc)2] · H2O complexes (M = Zn,Cd; Diap = 1,3-diazepane-2-thione; OAc = acetate) with N-H?O and O-H?O intra- and intermolecular hydrogen bonding interactions

The title complexes, [M(Diap)₂(OAc)₂] · H₂O (M = Zn,Cd; Diap = 1,3-diazepane-2-thione; OAc = acetate) with an MO₂S₂ configuration, have been characterized by X-ray crystallography as well as FT-IR, ¹H and ¹³C NMR spectroscopy. In these complexes, the metal atoms lie in a pseudo-tetrahedral environment and are coordinated by the thione sulfur atoms of two neutral 1,3-diazepane-2-thione ligands and one oxygen atom from each of two monodentate acetate anions. In both complexes, there are two intramolecular N-H?O hydrogen bonds, each being between one NH group of a Diap ligand and the uncoordinated O atom of an OAc ligand. The water molecule is also involved in hydrogen bonds, as an acceptor and as a donor twice, linking together three symmetry-related complexes. The Cd complex undergoes a structural phase transition from a monoclinic form at 150 K with Z′ = 2 to a smaller monoclinic cell at room temperature with Z′ = 1 without loss of crystallinity. The Zn complex does not exhibit an equivalent phase transition, and at 150 K is isostructural with the room-temperature form of the Cd complex. All three crystallographically independent molecules found for the Cd complex (two at low temperature and one at room temperature) have essentially the same structure except for small changes in the conformations of the ligands. Tetrahedral coordination with monodentate carboxylate ligands is common for Zn complexes of this kind, but is unusual for Cd complexes, and is the result of the bulky Diap ligands.     

Synthesis and Characterization of a Ditriflate-Bridged, Diiron(II) Complex with Syn-N-Donor Ligands: [Fe(2)(μ-OTf)(2)(PIC(2)DET)(2)](BARF)(2)

The synthesis and characterization of the diiron(II) complex [Fe(2)(μ-OTf)(2)-(PIC(2)DET)(2)](BARF)(2) (2), where PIC(2)DET is a 2,3-diethynyltriptycene-linked dipicolinic methyl ester ligand, are described. The dication in 2, contains, [Fe(2)(μ-OTf)(2)(PIC(2)DET)(2)](2+) two symmetry-equivalent iron atoms with octahedral coordination geometries. Each metal ion has a N(2)O(4) atom donor set that includes four atoms from two picolinic ester N,O chelate rings, as well as two oxygen atoms from the bridging trifluoromethanesulfonate groups. The Fe(2)(μ-OTf)(2) core of 2 is stabilized by two PIC(2)DET ligands that bind the two metal ions in a head-to-head fashion, leading to an Fe···Fe distance of 5.173(1)?. Molar conductivity data for 2 are consistent with Fe(2)(μ-OTf)(2)(PIC(2)DET)(2)](2+) retaining its identity in acetone solutions, where it behaves as a 2:1 electrolyte. (1)H NMR spectroscopic, solution (d(6)-acetone) and solid-state magnetic susceptibility data all indicate that the iron atoms of 2 are high-spin (S = 2). A fit of the magnetic data (2 - 300K) to a spin-only isotropic exchange Hamiltonian H = -2JS(1)·S(2) are consistent with weak antiferromagnetic coupling between the two iron atoms with J ~ -0.99(2) cm(-1) and g = 2.10(1).     

Chalcogenolato-bridged cyclometallated binuclear palladium complexes: Synthesis, spectroscopy, structures of [Pd2(μ-Cl)(μ-SMes)(C10H6NMe2-C,N)2] and [Pd2(μ-SePh)2(C10H6NMe2-C,N)2]

Reactions of orthometallated binuclear palladium complexes with NaER, obtained by NaBH₄ reduction of R₂E₂ in methanol, gave complexes, [Pd₂(μ-ER)₂(C^∩Y)₂] (HC^∩Y = N,N-dimethylbenzylamine (C₆H₅CH₂NMe₂), N,N-dimethylnaphthylamine (C₁₀H₇NMe₂), tri-o-tolylphosphine {P(tol-o)₃}; ER=SePh, SeMes, TePh, TeMes (Mes = 2,4,6-Me₃C₆H₂). Similar reactions of [Pd₂(μ-Cl)₂(C₁₀H₆NMe₂-C,N)₂] with Pb(SMes)₂ or MesSH in the presence of NaHCO₃ gave chloro/thiolato-bridged complex [Pd₂(μ-Cl)(μ-SMes)(C₁₀H₆NMe₂-C,N)₂]. The newly synthesized complexes were characterized by elemental analysis, UV-Vis, IR, NMR (¹H, ¹³C, ³¹P, ⁷⁷Se, ¹²⁵Te) spectroscopy. These complexes crystallized out preferentially in sym-cis configuration. A low energy charge transfer transition has been identified from chalcogenolate centers to an emptyπ^∗ orbital of cyclometallated ligand in absorption spectroscopy in these complexes. The structures of [Pd₂(μ-Cl)(μ-SMes)(C₁₀H₆NMe₂-C,N)₂] (1) and [Pd₂(μ-SePh)₂(C₁₀H₆NMe₂-C,N) ₂] (3) have been established by single crystal X-ray diffraction analyses. In the former, the two palladium atoms are held together by chloro and thiolato bridges whereas in the latter, the two phenylselenolato ligands bridge two palladium atoms. The pyrolysis of [Pd(μ-TeMes)(C₁₀H₆NMe₂-C,N)]₂ (10) in a furnace gave Pd₇Te₃ whereas thermolysis in TOPO afforded primarily PdTe₂.     

New coordination polymer based on salpn Schiff base and azide bridging ligands: Synthesis and structural characterization of {Na[Co(μ-salpn)(μ1,1-N3)2]}n (H2salpn = N,N′-bis(salicylidene)-1,3-diaminopropane)

One-pot reaction of cobalt(II) nitrate hexahydrate Co(NO₃)₂ · 6H₂O with H₂salpn (N,N′-bis(salicylidene)-1,3-diaminopropane) in presence of a large excess of sodium azide (NaN₃) gives the new Co(III) compound {Na[Co^III(μ-salpn)(μ_1,1-N₃)₂]}_n (1), which was characterized by single crystal X-ray diffraction analysis. The crystal structure shows polymeric 1D complex generated by the hexadentate Schiff base salpn²⁻ and two crystallographically different azide ligands. The two nitrogen atoms of the salpn ligand are bonded to the cobalt(III) ion while each phenoxo oxygen atom is bonded to the same Co(III) ion and to two equivalent sodium ions. Each azide ligand acts with the end-on bridging coordination mode between Co(III) and Na(I) ions. The Co(III) ion adopts a distorted octahedral geometry arising from two oxygen and two nitrogen atoms of the salpn ligand and from two nitrogen atoms of the two crystallographically different azide ligands in trans positions. Such [Co(salpn)(N₃)₂] entities are connected each other by sodium ions through four oxygen atoms of two equivalent Schiff base ligands and two nitrogen atom of the two different azide ligands to generate the 1D structure of 1.     

Synthesis of new (σ-N,N′-diazadiene)(η-alkene)platinum(0) compounds

Novel, thermally stable, dark-red to orange Pt⁰(σ²-N,N′-diazadiene)(η²-alkene) compounds have been synthesized in good yields from Pt⁰(COD)₂ or Pt⁰(NBE)₃, by stepwise substitution of the respective dienes or alkenes by an electron-poor alkene (dimethyl fumarate, maleic anhydride or fumaronitrile), followed by the appropriate diazadiene ligand in dry diethyl ether at 20 °C (diazadiene=various N,N′-disubstitued-1,4-diaza-1,3-dienes). The complex Pt(DBA)₂ is less suited as a precursor for the synthesis of Pt⁰(σ²-N,N′-diazadiene)(η²-alkene) compounds. These zerovalent Pt(diazadiene)(η²-alkene) compounds constitute a useful category of starting materials for synthetic organoplatinum chemistry and catalysis.     

A cyclic osmastannyl complex, Os(κ(Sn,P)-SnMe2C6H4PPh2)(κ-S2CNMe2)(CO)(PPh3) derived from the osmastannol complex, Os(SnMe2OH)(κ-S2CNMe2)(CO)(PPh3)2

Treatment of the six-coordinate trimethylstannyl complex, Os(SnMe₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1) with SnMe₂Cl₂ produces Os(SnMe₂Cl)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (2), which in turn reacts readily with hydroxide ion to give, Os(SnMe₂OH)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (3). The osmastannol complex 3 undergoes a reaction with 2 equivalents of ^tBuLi, in which one of the phenyl rings of a triphenylphosphine ligand is “ortho-stannylated”, without cleavage of the Os-Sn bond, to give the cyclic complex, Os(κ²(Sn,P)-SnMe₂C₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (4). This novel cyclic complex is selectively functionalised at the tin atom by reaction with SnMe₂Cl₂ which exchanges one methyl group for chloride giving the diastereomeric mixture, Os(κ²(Sn,P)-SnMeClC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (5a/5b). Crystal structure determination reveals that both diastereomers occur in the unit cell. The mixture, 5a/5b, undergoes reaction with hydroxide ion to give the diastereomeric osmastannol complexes, Os(κ²(Sn,P)-SnMeOHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (6a/6b) and with sodium borohydride to give the corresponding tin-hydride mixture, Os(κ²(Sn,P)-SnMeHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (7a/7b). Crystal structure determinations for 2, 4, and 5a/5b have been obtained.