Sulfide-bridged aggregates from the metalloligand [Pt2(μ-S)2(PPh3)4] and β-diketonate complexes of cobalt(II) and zinc(II)

Reaction of [Pt₂(μ-S)₂(PPh₃)₄] with a range of zinc(II) and cobalt(II) complexes ML₂, where L is a β-diketonate ligand CH₃COCHCOCH₃, PhCOCHCOPh, CF₃COCHCOTh (Th = 2-thienyl)] permits the synthesis of adducts [Pt₂(μ-S)₂(PPh₃)₄M(diketonate)]⁺, isolated as their salts in moderate yields. The cobalt and zinc acetylacetonate complexes were characterised by single-crystal X-ray diffraction studies, which reveal isomorphous structures, with tetrahedral heterometal centres.     

Thallium(III) complexes of the metalloligands [Pt2(μ-S)2(PPh3)4] and [Pt2(μ-Se)2(PPh3)4]

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with the diarylthallium(III) bromides Ar₂TlBr [Ar = Ph and p-ClC₆H₄] in methanol gave good yields of the thallium(III) adducts [Pt₂(μ-S)₂(PPh₃)₄TlAr₂]⁺, isolated as their salts. The corresponding selenide complex [Pt₂(μ-Se)₂(PPh₃)₄TlPh₂]BPh₄ was similarly synthesised from [Pt₂(μ-Se)₂(PPh₃)₄], Ph₂TlBr and NaBPh₄. The reaction of [Pt₂(μ-S)₂(PPh₃)₄] with PhTlBr₂ gave [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]⁺, while reaction with TlBr₃ gave the dibromothallium(III) adduct [Pt₂(μ-S)₂(PPh₃)₄TlBr₂]⁺[TlBr₄]⁻. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt₂(μ-S)₂(PPh₃)₄TlPh₂]BPh₄, [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]BPh₄ and [Pt₂(μ-S)₂(PPh₃)₄TlBr₂][TlBr₄] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl-S and Pt?Tl distances, and an increasing S-Tl-S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.     

The arylation of [Pt2(μ-S)2(PPh3)4]

Routes to the synthesis of the mixed sulfide-phenylthiolate complex [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ have been explored; reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess Ph₂IBr proceeds readily to selectively produce this complex, which was structurally characterised as its PF₆⁻ salt. Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with other potent arylating reagents (1-chloro-2,4-dinitrobenzene and 1,5-difluoro-2,4-dinitrobenzene) also produce the corresponding nitroaryl-thiolate complexes [Pt₂(μ-S){μ-SC₆H₂(NO₂)₂X}(PPh₃)₄]⁺ (X = H, F). The complex [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ reacts with Me₂SO₄ to produce the mixed alkyl/aryl bis-thiolate complex [Pt₂(μ-SMe)(μ-SPh)(PPh₃)₄]²⁺, but corresponding reactions with the nitroaryl-thiolate complexes are plagued by elimination of the nitroaryl group and formation of [Pt₂(μ-SMe)₂(PPh₃)₄]²⁺. [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ also reacts with Ph₃PAuCl to give [Pt₂(μ-SAuPPh₃)(μ-SPh)(PPh₃)₄]²⁺.     

Platinum(II) halide complexes of PPh2(CFCF2) and PPh2(CClCF2). The synthesis and crystal structure of [PtI(μ-I){PPh2(CXCF2)}]2, (X = F, Cl); the first crystallographically characterised iodide-bridged platinum(II) phosphine dimers

The reactions of the fluorovinyl-substituted phosphines PPh₂(CFCF₂) and PPh₂(CClCF₂), with K₂PtX₄ (X = Br, I) have been investigated. The resulting complexes have been characterized by a combination of ¹⁹F and ³¹P{¹H} NMR, IR and Raman spectroscopy. The reactions of these phosphines with K₂PtBr₄ yield the monomeric complexes cis-[PtBr₂{PPh₂(CFCF₂)}₂] (1) and trans-[PtBr₂{PPh₂(CClCF₂)}₂] (2), respectively, whilst the reactions with K₂PtI₄ yield both the monomeric species trans-[PtI₂{PPh₂(CXCF₂)}₂], {X = F (3), Cl (4)}, and the dimeric species [PtI(μ-I){PPh₂(CXCF₂)}]₂, {X = F (5), Cl (6)}. The dimers 5 and 6 represent the first crystallographically characterised platinum(II) iodide-bridged phosphine complexes, and both adopt the symmetric-trans structure.     

Synthesis and crystal structure of a cis-oxime-oximate bridged tetra coordinated open-book shaped new dicopper(II/II) complex [Cu2(μ-Hdmg)2(Hdmg)]ClO4: First report of unusual oxime OH bridging

Reaction of Cu(ClO₄)₂ · 6H₂O with dimethylglyoxime (H₂dmg) and triethylamine (pH ∼ 4-5) at room temperature affords oxime bridged dicopper(II/II) complex of formula [Cu₂(μ-Hdmg)₂(Hdmg)]ClO₄ · H₂O (1) (H₂dmg = dimethylglyoxime). The complex has been characterized by single-crystal X-ray diffraction analysis. The structure consists of one dinuclear complex cation, [Cu₂(μ-Hdmg)₂(Hdmg)], and one anion. Two copper(II) ions at a distance of 3.558 Å are bridged by one oxime and one oximate groups in cis arrangement. The geometry around each copper atom is square planar with an overall open-book type arrangement of these planes. The average copper-oxygen distance is (1.953 Å) and the average copper-nitrogen distance is 2.003 Å. The Cu-O(oxime) distance (1.963 Å) is higher than the Cu-O(oximate) distance (1.942 Å) due to different protonation label. The room temperature value of χ_MT for the title complex (χ_M being the molar magnetic susceptibility for two copper atoms) is low (ca. 0.42 cm³ K mol⁻¹) (μ_eff = 1.52 μ_B). The UV-Vis spectrum of the complex shows a characteristic broad band at 470 nm.     

Study of Pt(II)-aromatic amines complexes of the types cis- and trans-Pt(amine)2I2, [Pt(amine)4]I2 and I(amine)Pt(μ-I)2Pt(amine)I

Pt(II) complexes of the types cis- and trans-Pt(amine)₂I₂ with amines containing a phenyl group were synthesized and studied mainly by IR and multinuclear (¹⁹⁵Pt, ¹H and ¹³C) magnetic resonance spectroscopies. The compounds are not very soluble. In ¹⁹⁵Pt NMR spectroscopy, the cis isomers were observed at slightly lower fields than the trans analogues (average Δδ = 11 ppm) in acetone. In ¹H NMR, the NH groups were also found at slightly lower fields in the cis isomers. The coupling constants ²J(¹⁹⁵Pt-¹HN) varied from 53 to 85 Hz and seem slightly smaller in the trans configuration. The ¹³C NMR spectra of most of the complexes were measured. No coupling constants J(¹⁹⁵Pt-¹³C) were detected due to the low solubility of the compounds. The cis isomers containing a phenyl group on the N atom could not be isolated except for Ph-NH₂ which was shown to be a mixture of isomers in acetone. The tetrasubstituted ionic compounds [Pt(amine)₄]I₂ for the less crowded ligands were also studied mainly by NMR spectroscopy in aqueous solution. The ¹⁹⁵Pt chemical shifts vary between −2855 and −2909 ppm. The coupling constants ³J(¹⁹⁵Pt-¹H) are about 40 Hz. The iodo-bridged dinuclear species I(amine)Pt(μ-I)₂Pt(amine)I were also synthesized and characterized. Two isomers are present in acetone solution for most of the compounds. Their δ(Pt) signals were observed at about −4000 ppm and their coupling constants ²J(¹⁹⁵Pt-¹HN) are around 69 Hz.     

An electrospray mass spectrometry-directed survey of the coordination chemistry of the metalloligand [Pt2(μ-S)2(PPh3)4] with platinum(II) and palladium(II) chloride substrates: influence of metal-ligand lability on product type

The reactivity of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] towards a wide range of platinum(II) and palladium(II) chloride complex substrates [L₂MCl₂] has been explored, using the technique of electrospray ionisation mass spectrometry to directly analyse reaction solutions. In the majority of cases, products are formed by addition of the ML₂²⁺ fragment to the {Pt₂S₂} core, giving trinuclear species [Pt₂(μ-S)₂(PPh₃)₄ML₂]²⁺. The adducts with Pt(diene) [diene=cyclo-octa-1,5-diene (cod), norbornadiene], Pd(cod), Pd(bipy) (bipy=2,2^′-bipyridine), Pt(PMe₃)₂ and Pt(PTA)₂ (PTA=phosphatriaza-adamantane) moieties were synthesised and characterised on the macroscopic scale, with [Pt₂(μ-S)₂(PPh₃)₄Pt(cod)] (BF₄)₂ and [Pt₂(μ-S)₂(PPh₃)₄Pd(bipy)] (PF₆)₂ also characterised by X-ray diffraction studies. No metal scrambling was found to occur, as has been observed in some previous cases involving the related complexes [Pt₂(μ-Se)₂(PPh₃)₄] and [Pt₂(μ-S)₂(dppe)₂] (dppe=Ph₂PCH₂CH₂PPh₂). With cis-[PtCl₂(SOMe₂)₂] the species [Pt₂(μ-S)₂(PPh₃)₄PtCl(SOMe₂)]⁺ was formed, as a result of the lability of the SOMe₂ ligand. With palladium(II)-phosphine systems, the observed product species is dependent on the phosphine; the bulky PPh₃ ligand in [PdCl₂(PPh₃)₂] leads primarily to the analogous known species [Pt₂(μ-S)₂(PPh₃)₄PdCl(PPh₃)]⁺, and a small amount of the metal-scrambled species [PtPd₂S₂(PPh₃)₅Cl]⁺. In contrast, [PdCl₂(PTA)₂], containing the small PTA ligand gave [Pt₂(μ-S)₂(PPh₃)₄Pd(PTA)₂]²⁺.     

Hydrido-derivatives of [Ir4(CO)10(diphosphine)]: X-ray analyses of [Ir4H(CO)9(μ-Ph2PH(CH3)PPh2)] and [Ir4 H(CO)9(μ-Ph2P(CH2)nPPh2)] (n = 2, 3)

Some novel hydrido-anions of general formula [Ir₄H(CO)₉(μ-L-L)]⁻ (L-L = Ph₂PCH(CH₃)PPh₂, Ph₂P(CH₂)₂PPh₂, Ph₂P(CH₂)₃PPh₂ and Ph₂AsCH₂AsPh₂) have been obtained by the reaction of [Ir₄(CO)₁₀(μ-L-L)] with the base 1,8-diazabicyclo[5.4.0]undec-7-ene in wet dichloromethane. According to IR and ¹H, ³¹P and ¹³C NMR data at low temperature, these anionic derivatives display a single conformation in solution: three edge-bridging COs around the triangular basal face and both the hydride and the bidentate ligands located in axial positions relative to this face. The structures of four compounds were established by X-ray diffraction studies, which confirmed the configuration proposed on the basis of spectroscopic data.     

N-Heterocyclic carbene gold(I) and silver(I) adducts of [Pt2(μ-S)2(PPh3)4]

Reaction of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] with the N-heterocyclic carbene (NHC) complexes IPrAuCl, IMesAuCl and IMesAgCl in methanol gave the first examples of metal adducts of [Pt₂(μ-S)₂(PPh₃)₄] that contain NHC ligands, namely [Pt₂(μ-S)₂(PPh₃)₄AuL]⁺ (L = IPr, IMes) and [Pt₂(μ-S)₂(PPh₃)₄AgIMes]⁺. The complexes were isolated as hexafluorophosphate salts. Reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess IPrAuCl in refluxing methanol yielded only the mono-adduct, in contrast to the behaviour with the gold(I) phosphine complex Ph₃PAuCl, which undergoes double addition giving [Pt₂(μ-SAuPPh₃)₂(PPh₃)₄]²⁺. The X-ray structure of [Pt₂(μ-S)₂(PPh₃)₄AuIPr]PF₆ was determined and reveals that the ‘free’ sulfide is substantially sterically protected by the IPr ligand, accounting for the low reactivity towards addition of a second AgIPr⁺ moiety.     

A convenient preparation of [(Ph3P)3Pt2(μ-H)(μ-PPh2)Ph]BF4 by rearrangement of trans-aquahydridobis(triphenylphosphine) platinum(II) tetrafluoroborate

The cation [(PPh₃)₂Pt(H)OH₂]⁺ previously suggested as an intermediate in the synthesis of [(Ph₃P)₃Pt₂(μ-H)(μ-PPh₂)Ph]⁺ has been isolated as the tetrafluoroborate salt and characterised by X-ray crystallography. The structure shows a large unit cell with three independent cations and extensive hydrogen bonding between the water molecules and the tetrafluoroborate anions. The rearrangement of [(PPh₃)₂Pt(H)OH₂]⁺ in aqueous THF provides a convenient high yield route to [(Ph₃P)₃Pt₂(μ-H)(μ-PPh₂)Ph]⁺.     

Influence of chain length on mono- versus di-alkylation in the reactivity of [Pt2(μ-S)2(PPh3)4] towards α,ω-dihalo-n-alkanes; a synthetic route to platinum(II) ω-haloalkylthiolate complexes

The reactions of [Pt₂(μ-S)₂(PPh₃)₄] with α,ω-dibromoalkanes Br(CH₂)_nBr (n = 4, 5, 6, 8, 12) gave mono-alkylated [Pt₂(μ-S){μ-S(CH₂)_nBr}(PPh₃)₄]⁺ and/or di-alkylated [Pt₂(μ-S(CH₂)_nS}(PPh₃)₄]²⁺ products, depending on the alkyl chain length and the reaction conditions. With longer chains (n = 8, 12), intramolecular di-alkylation does not proceed in refluxing methanol, with the mono-alkylated products [Pt₂(μ-S){μ-S(CH₂)_nBr}(PPh₃)₄]⁺ being the dominant products when excess alkylating agent is used. The bridged complex [{Pt₂(μ-S)₂(PPh₃)₄}₂{μ-(CH₂)₁₂}]²⁺ was accessible from the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with 0.5 mol equivalents of Br(CH₂)₁₂Br. [Pt₂(μ-S){μ-S(CH₂)₄Br}(PPh₃)₄]⁺ can be cleanly isolated as its BPh₄⁻ salt, but undergoes facile intramolecular di-alkylation at −18 °C, giving the known species [Pt₂(μ-S(CH₂)₄S}(PPh₃)₄]²⁺. The reaction of I(CH₂)₆I with [Pt₂(μ-S)₂(PPh₃)₄] similarly gives [Pt₂(μ-S){μ-S(CH₂)₆I}(PPh₃)₄]⁺, which is fairly stable towards intramolecular di-alkylation once isolated. These reactions provide a facile route to ω-haloalkylthiolate complexes which are poorly defined in the literature. X-ray crystal structures of [Pt₂(μ-S){μ-S(CH₂)₅Br}(PPh₃)₄]BPh₄ and [Pt₂(μ-S(CH₂)₅S}(PPh₃)₄](BPh₄)₂ are reported, together with a study of these complexes by electrospray ionisation mass spectrometry. All complexes fragment by dissociation of PPh₃ ligands, and the bromoalkylthiolate complexes show additional fragment ions [Pt₂(μ-S){μ-S(CH₂)_n−2CHCH₂}(PPh₃)_m]⁺ (m = 2 or 3; m ≠ 4), most significant for n = 4, formed by elimination of HBr.     

A one-dimensional copper (II) coordination polymer [Cu3(ampym)2(μ1,1-N3)4(μ1,3-N3)2(dmf)2]n (ampym = 2-aminopyrimidine) containing both end-on and end-to-end azido bridges

A new polynuclear copper (II) complex, derived from the azido-bridging ligand and 2-aminopyrimidine, has been synthesized and its 3-D structure has been determined by X-ray diffraction methods at two different temperatures. The compound crystallizes in the triclinic system space group, with the central copper atom lying on an inversion centre. The crystal structure is built up by trinuclear units (each of them contains two double end-on azido bridges) linked through two azide ions in an end-to-end (EE) fashion, to yield the polymer chain [Cu₃(ampym)₂(μ_1,1-N₃)₄(μ_1,3-N₃)₂(dmf)₂]_n. Magnetic susceptibility measurement shows a ferromagnetic interaction above 30 K, whereas a weak anti-ferromagnetic interaction prevails in the range of 30-2 K.     

A novel tetranuclear hydrogenphosphate-bridged Cu(II) cluster. Synthesis, structure, spectroscopy and magnetism of [Cu4(dpyam)4(μ4,η-HPO4)2(μ-X)2]X2(H2O)6 (X = Cl, Br)

Two novel tetranuclear compounds with an unprecedented mode of a hydrogenphosphato bridge, [Cu₄(dpyam)₄(μ₄,η³-HPO₄)₂(μ-X)₂]²⁺ (in which dpyam = di-2-pyridylamine and X = Cl (1), Br (2)) have been synthesised and characterised structurally and magnetically. The Cu(II) ions in the structures each display a square-pyramidal geometry, with two tridentate hydrogenphosphato groups bridging four copper atoms in a μ₄,η³ coordination mode which is rarely found in hydrogenphosphate metal compounds. Each (different) pair of Cu(II) ions is additionally bridged by halide ions, with relatively long Cu-X distances (2.551(3)-2.604(3) Å for 1 and 2.707(1)-2.766(2) Å for 2) and subsequently also a small Cu-X-Cu angle (65.7(1)° and 65.1(1)° for 1 and 61.6(1)° and 62.4(1) for 2) and a large Cu-X-Cu angle (95.5(1)° and 96.5(1)° for 1 and 91.1(1)° and 92.6(1)° for 2). Cu?Cu distances in the tetranuclear units varies from 2.802(3) to 5.232(3) Å for 1 and from 2.834(1) to5.233(1) Å in 2. The lattice structures are stabilised by extensive intermolecular hydrogen bonds. The magnetic susceptibility measurements down to 5 K revealed a weak ferromagnetic interaction between the outer pairs of Cu(II) ions which vary from 22 to 46 cm⁻¹ in 1 and 12 to 33 cm⁻¹ in 2 and a moderately strong antiferromagnetic interaction between the inner Cu(II) ions of −79 cm⁻¹ in 1 and −83 cm⁻¹ in 2, via the Cu-O-P-O-Cu pathway.     

A facile reaction of bibenzyl trisulfide with [(η-C5H5)Cr(CO)3]2: formation of a thiolato-bridged dichromium complex of [CpCr(CO)2(SBz)]2 (Bz = PhCH2-)

The reaction of [CpCr(CO)₃]₂ (Cp = η⁵-C₅H₅) (1) with an equivalent of Bz₂S₃ at ambient temperature gave [CpCr(CO)₂]₂S (3) [L.Y. Goh, T.W. Hambley, G.B. Robertson, Organometallics 6 (1987) 1051], novel complexes of [CpCr(CO)₂(SBz)]₂ (4) and together with [CpCr(SBz)]₂S (5) as main products. Thermolytic studies showed that 4 underwent complete decarbonylation to give [CpCr(SBz)]₂S (5). Final thermal decomposition of 3 and 5 eventually yielded Cp₄Cr₄S₄ (6) (Goh et al., 1987) after prolonged reaction at 100 °C. However, the reaction of [CpCr(CO)₂]₂ (CrCr) (2) with Bz₂S₃ was much slower at ambient temperature which required 72 h to complete eventually yielding 3 and 5. All the products have been characterized by elemental and spectral analyses. 4 has been structurally determined.     

Synthesis and structural characterisation of new cationic dinuclear ruthenium(II) thiolato complexes of the type [Ru2(η-arene)2(μ-p-S-C6H4-Br)3]

Dinuclear dichloro complexes [Ru(C₆H₆)Cl₂]₂, [Ru(p-MeC₆H₄ ⁱPr)Cl₂]₂, [Ru(1,2,4,5-C₆H₂Me₄)Cl₂]₂, and [Ru(C₆Me₆)Cl₂]₂ react in ethanol with p-bromothiophenol to give the corresponding cationic complexes [Ru₂(C₆H₆)₂(p-S-C₆H₄-Br)₃]⁺ (1), [Ru₂(p-MeC₆H₄ ⁱPr)₂(p-S-C₆H₄-Br)₃]⁺ (2), [Ru₂(1,2,4,5-C₆H₂Me₄)₂(p-S-C₆H₄-Br)₃]⁺ (3), and [Ru₂(C₆Me₆)₂(p-S-C₆H₄-Br)₃]⁺ (4), which can be isolated in quantitative yield as their chloride salts. X-ray structure analysis of these complexes shows that the nature of the arene ligand influences the folding of the p-S-C₆H₄-Br units. In 1, where the less hindered arene ligand is present, the three phenyl rings of the thiolato units are not constrained to a coplanar arrangement, whereas in 4 the C₆Me₆ forces the three phenyl rings to be in perfect planarity. Complexes 2 and 3 show an intermediary arrangement.     

A versatile entry into aqueous niobium chemistry: isolation and structure of the intermediate Nb4(μ2-O)2(μ2-OC2H5)4Cl4(OC2H5)4(HOC2H5)4

The reduction of ethanolic solutions of niobium pentachloride with zinc, followed by treatment with aqueous acids serves as a versatile entry into the aqueous solution chemistry of niobium. From the zinc-reduced solution, the major intermediate, Nb₄(μ₂-O)₂(μ₂-OC₂H₅)₄Cl₄(OC₂H₅)₄(HOC₂H₅)₄, was isolated and the crystal structure determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pccn, with Z=4, a=21.0105(9), b=11.0387(5), c=19.1389(8), V=4438.9(3) ų, M_r=1090.19,R₁=0.0327 and wR₂=0.0876. The structure revealed a centrosymmetric tetrameric Nb(IV) complex, consisting of a pair of edge-sharing bi-octahedral Nb₂(μ₂-OC₂H₅)₄Cl₂(OC₂H₅)₂(HOC₂H₅)₂ units that are joined by two axial oxo ligands. The Nb-Nb distance of 2.7458(3) Å is consistent with a single metal-metal bond.     

Influence of CH3 group of μ-N-C-S ligand on the properties of [Fe2(C4H5N2S)2(NO)4] complex

Bi-nuclear neutral sulfur-nitrosyl iron complex [Fe₂(SR)₂(NO)₄] (I) has been obtained by replacement of thiosulfate ligands in dianion [Fe₂(S₂O₃)₂(NO)₄]²⁻ by 1-methyl-imidazole-2-yl. From X-ray analysis data, the complex has centrosymmetrical dimeric structure, with the iron atoms being linked via μ-N-C-S bridge. From Mossbauer spectroscopy, isomeric shift δ_Fe is 0.180(1) mm/s and quadrupole splitting ΔE_Q is 0.928(2) mm/s at T = 290 K. By comparative studying the mass-spectra in the gaseous phase of solid samples decomposition and kinetics of NO release in 1% aqueous solutions of dimethylsulfoxide, using of the ligand with CH₃ substituent in position 1 of imidazole-2-thiol was shown to yield a more stable donor of nitrogen monoxide than earlier obtained analog with imidazole-2-thiol, [Fe₂(C₃H₃N₂S)₂(NO)₄].     

Synthesis and characterisation of adducts of [Pt2(μ-S)2(PPh3)4] with organo-palladium and platinum-hydride substrates

The reactions of [Pt₂(μ-S)₂(PPh₃)₄] towards a range of palladium(II) complexes containing organometallic ligands (cyclopalladated N-donor ligands, η³-allyl, phenyl) have been explored, leading to the formation of a series of cationic, trinuclear sulfido-bridged aggregates containing {Pt₂PdS₂} cores. [Pt₂(μ-S)₂(PPh₃)₄] also reacts with the platinum(II) hydride complex trans-[PtHCl(PPh₃)₂] giving the adduct [Pt₂(μ-S)₂(PPh₃)₄PtH(PPh₃)]⁺. X-ray crystal structure determinations on the complexes [Pt₂(μ-S)₂(PPh₃)₄PdPh(PPh₃)]PF₆ and [Pt₂(μ-S)₂(PPh₃)₄PtH(PPh₃)]PF₆ are reported, and show the expected bis μ₃-sulfido aggregates with three square-planar metal centres.     

Synthesis, X-ray crystal structure and properties of a novel tetranuclear unsymmetrical (μ-SO4) copper(II) complex: relevance to SO2 fixation

The synthesis, by fixation of SO₂, the unusual crystal structure, and the spectral and redox properties of the new compound [Cu₄(TPPNOL)₂(μ-SO₄)₂](ClO₄)₂ (1) [HTPPNOL (N,N,N′-tris-(2-pyridylmethyl)-1,3-diaminopropan-2-ol)] are reported. In 1, the copper(II) ions are bridged by the alkoxo oxygen atoms of the HTPPNOL ligand and by exogenous sulfate bridges. The structure of 1 consists of a centro-symmetric tetranuclear core or a “Dimer of Dimers” complex, in which a μ-O,O′ sulfate oxygen atom is further coordinated to the copper centre of another similar dinuclear unit through a μ-O,O, sulfate bridge resulting in a tetranuclear arrangement. Thus, the dinuclear units are linked by two μ-O,O sulfate bridges. The simultaneous presence of two distinct coordination modes for the sulfate group in this structure is rare and 1 represents the first coordination compound presenting μ-O,O′ and μ-O,O type structures. The SO₂ fixation was monitored by changes in the electronic spectra which indicated the formation of the intermediate hydroxo complex [Cu₂(TPPNOL)(OH)₂]⁺, in basic medium, which, we propose, acts as the nucleophile in the SO₂ fixation mechanism.     

Mono(p-tolyl)platinum(II) and bis(p-tolyl)platinum(II) complexes of diethylsulfide as reagents for organoplatinum synthesis. Structures of [Pt(p-Tol)2(μ-SEt2)]2 and PtCl(p-Tol)(bpy) (bpy=2,2′-bipyridine)

The complex trans-PtCl(p-Tol)(SEt₂)₂ is obtained from the reaction of [Pt(p-Tol)₂(SEt₂)]₂ with PtCl₂(SEt₂)₂ and SEt₂ in mole ratio 1:2:2. The mono(p-tolyl)platinum(II) and bis(p-tolyl)platinum(II) complexes of diethylsulfide react with 2,2′-bipyridine to form the complexes PtX(p-Tol)(bpy) (X=p-Tol, Cl) and are useful reagents for organoplatinum chemistry. X-ray crystal structures are presented for square planar PtCl(p-Tol)(bpy) and the centrosymmetric dimer [Pt(p-Tol)₂(μ-SEt₂)]₂.