Synthesis and reactions of phenylimidotrimethyl-bis(trimethylphosphine)-rhenium(V). Synthesis and X-ray crystal structure of bis(trimethylsilylmethyl)oxo-rhenium(V)-μ-oxo-tetrakis(trimethylphosphine)rhenium (I)-(trimethylsilylmethyl)dioxorhenium(V), (ReRe)

The interaction of phenylimidotrichloro bis(trimethylphosphine) with dimethylmagnesium gives the trimethyl compound, Re(NPh)Me₃(PMe₃)₂. Exchange reactions between the trichloro and trimethyl compounds are studied by ¹H nuclear magnetic resonance and the intermediates Re(NPh)Me₂Cl(PMe₃)₂ and Re(NPh)MeCl₂(PMe₃)₂ isolated.The trimethyl reacts with fluoroboric acid to give a phenylamido complex [Re(NHPh)Me₂F(PMe₃)₂]BF₄, with acetic acid to give Re(NPh)Me(CO₂Me₃)₂, and with trityltetrafluoroborate to give [Re(NPh)Me₂(PMe₃)₂]BF₄.The interaction of Re(NPh)Cl₃(PMe₃)₂ with excess of bis(trimethylsilylmethyl)magnesium and of trimethyl-phosphine in tetrahydrofuran gives an unusual tri-rhenium compound, (Me₃SiCH₂)₃(O)Re-μ-O-Re(PMe₃)₄Re(O)₂(CH₂SiMe₃) whose structure as a thf solvate, has been determined by X-ray crystallography. Crystals of the latter are monoclinic, space group P2₁/n with a = 15.512(3), b = 15.392(2), c = 21.506(4) Å, β = 100.19(2)°, Z = 4. The structure has been refined to an R of 0.07 for 5028 observed diffractometer data. The molecule is tri-nuclear with the central rhenium carrying four PMe₃ groups being bound to the second rhenium by a short ReRe bond and to the third by an asymmetric oxygen bridge. The end rhenium bound to the bridge oxygen carries two CH₂SiMe₃ groups and an oxygen atom, while the other has one CH₂SiMe₃ group and two oxygen atoms.     

The spectroscopic and structural characterization of trans-hydrido(1,1-dimethylallene(bis(tricyclohexylphosphine)platinum(II) hexafluorophosphate

The platinum hydride cation, trans-[PtH(CH₃OH)(P(C₆H₁₁)₃)₂]⁺ reacts with 1,1-dimethylallene at room temperature in dichloromethane to lose methanol and form an allene complex which has been characterized by ¹H NMR spectroscopy and X-ray diffraction. Crystals grown from a mixture of hexane and o-dichlorobenzene are monoclinic, space group P2₁/n, with cell dimensions a 14.807(2), b 29.404(7), c 11.621(2) Å and β 90.75(1)°. There are four units of trans-[PtH(C₅H₈)(P(C₆H₁₁)₃)₂]PF₆, C₆H₄Cl₂ in the cell. Three dimensional X-ray data collected by diffractometer techniques have permitted full matrix least-squares refinement to a conventional agreement factor R = 0.052. The platinum atom has a square planar coordination geometry, with the planar allene ligand bonded at an angle of 89.2(6)° to the coordination plane, and PtC distances of 2.305(10) and 2.233(10) Å.     

Synthesis and structural characterization of Zn (II), Ag (I) and Pd (II) complexes with 2,4-diamino-5-nitroso-6-oxopyrimidine. Crystal and molecular structure of [ZnCl2 (L) (H2O)] and [Ag (NO3) (L)2]

Three complexes of formula [ZnCl₂ (L) (H₂O)][Ag (NO₃) (L)₂] and [PdCl₂ (L)] 2H₂O have been obtained by reacting the ligand 24-diamino-5-nitroso-6-oxo-pyrimidine with the corresponding metal salt The complexes have been characterized by thermal and spectroscopic techniques and for the two former by single crystal X-ray diffraction [ZnCl₂ (L) (H₂O)]: C₅H₉N₅O₃Cl₂Zn a=9197 (5)b=11663 (6) c=10166 (7) Åβ=9066 (3) monoclinic P2₁/n Z=4 [Ag (NO₃) (L)₂]: C₁₀H₁₄N₁₁O₇Aga=15920 (5) b=7395 (5) c=14408 (5) Å β=97678 (5) monoclinic C2/c Z=4 In all of them the ligand coordinates in a neutral bidentate fashion through the exocyclic nitroso and oxo groups in the two former complexes through the N(5)/O(6) atoms whereas in the latter the donor atoms are the O(5)/O(6) These coordination modes are connected with the fact that the ligand is able to adopt two conformations depending on the intramolecular N(4)H O(5) hydrogen bond.     

Saturation molalities and standard molar enthalpies of solution of cytidine(cr), hypoxanthine(cr), thymidine(cr), thymine(cr), uridine(cr), and xanthine(cr) in H2O(l)

Saturation molalities m(sat) in H₂O(l) have been measured for the substances cytidine(cr), hypoxanthine(cr), thymidine(cr), thymine(cr), uridine(cr), and xanthine(cr) by using h.p.l.c. The states of hydration were established by performing Karl-Fischer analyses on samples of these substances, which had been allowed to equilibrate with their respective aqueous saturated solutions for several days at T≈298 K and then dried with air at T≈296 K for ≈24 h. The crystalline forms of the substances were identified by comparison of the results of X-ray diffraction measurements with results from the literature. Also, molar enthalpies of solution Δ_solH_m(cal) for these substances were measured by using an isoperibol solution calorimeter. A self-association (stacking) model was used to estimate values of the activity coefficients γ and relative apparent molar enthalpies L_φ for these substances. These γ and L_φ values were used to adjust the measured values of m(sat) and Δ_solH_m(cal) to the standard state and thus obtain values of the standard molar Gibbs free energy Δ_solG^∘_m and enthalpy changes Δ_solH_m^∘ for the dissolution reactions of these substances. The values of the pKs and of the standard molar enthalpies of the ionization reactions were also used to account for speciation of the substances in the calculations of Δ_solG_m^∘ and Δ_solH_m^∘. Values of standard molar enthalpies of formation Δ_fH_m^∘, standard molar Gibbs free energies of formation Δ_fG_m^∘, and standard partial molar entropies S_2,m^∘ for the aqueous species of hypoxanthine and xanthine were calculated. A detailed summary and comparison of thermodynamic results from the literature for these substances is presented.     

The structure of (dibenzylideneacetone)(pentamethylcyclopentadienyl)rhodium(I)

The structure of (dibenzylideneacetone)(pentamethylcyclopentadienyl)rhodium(I), Rh(C₅Me₅)(dba), (dba = PhCHCHCOCHCHPh, Ph = C₆H₅, Me = CH₃), has been determined from three-dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a final R index on F of 0.035 based on 2100 observations above background. The material crystallizes in the monoclinic space group C⁵_2hP2₁/a, with four molecules in a cell of dimensions a=14.348(12), b=14.063(13), c=11.393(10) », β=104.42(3)°. The observed and calculated densities are 1.35(3) and 1.41 g/cm³. The compound is monomeric. The Rh atom is bonded to the C₅Me₅ ring on one side and to the dba molecule through the two olefinic double bonds on the other. The C₅ and Me₅ portions of the C₅Me₅ ring are planar, but not coplanar as the Me group are bent away from the Rh atom by 0.10 » relative to the C₅ plane. The dba molecule is in the s-cis,s-cis conformation with the two double bonds in a plane which is parallel to the planes of the C₅Me₅ ring. The rest of the dba molecule is nonplanar with the CO group pointing away from Rh. The olefinic double bonds have lengthened on coordination to 1.411(9) ». The H atoms on the terminal C atoms of the dba molecule are in very close contact, the refined H?H distance being 1.83(9) ». It is suggested that the strain imposed on the coordinated dba molecule by this interaction might contribute to its ease of dissociation from the complex in solution and hence account for the catalytic properties of the complex.     

Mixed halide dialkyldithiophosphate derivatives of arsenic(III) and antimony(III)

Mixed chloride dialkyldithiophosphates of arsenic(III) and antimony(III), [(RO)₂PSS]_nMCl_3?n (M = As, Sb; n = 1, 2; R = C₂H₅, n-C₃H₇, i-C₃H₇ and i-C₄H₉) have been synthesized for the first time by the reac metal chlorides with sodium dialkyldithiophosphates or alternatively by co-disproportionation reactions of metal chlorides with metal tris(dialkyldithiophosphates) in different stoichiometric ratios. Mixed halide dialkyl-dithiophosphates of antimony(III) have also been prepared by the cleavage reactions of antimony tris(diisopropyldithiophosphate) with bromine or iodine. Hydrolysis reactions of a few of these compounds have also been studied. The new compounds have been characterized by elemental analyses, molecular weight determinations (cryoscopic) as well as IR and NMR (¹H, ³¹P) data; chelated structures with bidentate dialkyldithiophosphate groups are proposed.     

Synthesis and crystal structure of tris(ethylenediamine)cobalt(III) bis(tetrachloroaurate(III)) chloride

The binary complex salt [Co(N₂C₂H₈)₃][AuCl₄]₂Cl has been synthesized. Its crystal structure has been determined. Crystal data for C₆H₂₄N₆Cl₉AuCo: a = 20.8976(14) Å, b = 14.4773(9) Å, c = 7.9944(5) Å; β = 110.809(2)°; V = 2260.9(3) ų, space group C2/c, Z = 4, d _calc = 2.798 g/cm³. The plane square environment of the gold atom of the complex anion is completed to a tetragonal pyramid by the chlorine atom of the neighboring complex anion (Au…Cl 3.538 Å). The structure is layered. Layers of complex cations and complex anions alternate along the X axis.     

Structural characterization of a seven-coordinated organotin(IV) complex: Tris(dimethyl sulphoxide)nitratodiphenyltin(IV) nitrate

A seven-coordinated organotin(IV) compound has been obtained and its IR spectroscopic properties and X-ray crystal structure are reported. Crystals are monoclinic (p2₁/c) with unit-cell dimensions: a 16.017(9), b 10.365(5), c 15.994(8) Å, β 96.1(1)°, Z = 4. The structure has been determined from diffractometer data (Cu-K_a radiation) by conventional Patterson and Fourier techniques and refined by block-diagonal least-squares procedure to an R value of 0.093 for 4298 independent reflections. The structure consists of monomeric seven-coordinated cations [Sn(C₆H₅)₂NO₃{(CH₃)₂SO}₃] and NO₃- anions. Coordination around tin is pentagonal bipyramidaI with the bidentate nitrate group and the three dimethyl sulphoxide molecules in the equatorial positions and the two phenyl rings at the apices. Literature on seven-coordinated tin(IV) compounds and nitratotin(IV) complexes is quoted and discussed.     

Structure of bis(2-methylimino-3-penten-4-onato) nickel(II). properties of nickel(II) ketoiminates

A new volatile complex Ni(mi-aa)₂ [mi-aa = CH₃C(NCH₃)CHC(O)CH₃)] is synthesized and its crystal structure is determined (APEX DUO diffractometer with a 4C CCD detector, λMoK _α, graphite monochromator, T = 100 K). Crystallographic data for Ni(mi-aa)₂ are as follows: space group Pbca, a = 5.4058(3) Å, b = 11.8684(6) Å, c = 19.8472(10) Å, V = 1273.4(1) ų, Z = 4. The Ni(II) atom is coordinated by the O and N atoms of two ligands. The Ni-O and Ni-N distances are 1.8390(9) Å and 1.926(1) Å; the chelate ONiN angle is 92.52(4)°. The complex has the molecular structure formed from the isolated molecules of Ni(mi-aa)₂ bound by van der Waals interactions. For some complexes, the TG study is performed and the intermolecular interaction energy in the crystals is calculated.     

Aminobis(phenolate)s of imidomolybdenum(VI) and -tungsten(VI)

The reactions of trans-[MoO(ONO^Me)Cl₂] 1 (ONO^Me = methylamino-N,N-bis(2-methylene-4,6-dimethylphenolate) dianion) and trans-[MoO(ONO^tBu)Cl₂] 2 (ONO^tBu = methylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenolate) dianion) with PhNCO afforded new imido molybdenum complexes trans-[Mo(NPh)(ONO^Me)Cl₂] 3 and trans-[Mo(NPh)(ONO^tBu)Cl₂] 4, respectively. As analogous oxotungsten starting materials did not show similar reactivity, corresponding imido tungsten complexes were prepared by the reaction between [W(NPh)Cl₄] with aminobis(phenol)s. These reactions yielded cis- and trans-isomers of dichloro complexes [W(NPh)(ONO^Me)Cl₂] 5 and [W(NPh)(ONO^tBu)Cl₂] 6, respectively. The molecular structures of 4, cis-6 and trans-6 were verified by X-ray crystallography. Organosubstituted imido tungsten(VI) complex cis-[W(NPh)(ONO^tBu)Me₂] 7 was prepared by the transmetallation reaction of 6 (either cis or trans isomer) with methyl magnesium iodide.     

Carbon-nitrogen bond formation in the reaction of the reaction of diphenyl diazomethane Ph2 CN2 with diiron-carbene complexes (Fe2(CO)7x03BD;-C(R)C(NEt2)x03BD;-C(R)C(NEtx03BC;-C(R)C(NEt2)N(NCPh2)x03BC;-C(R)C(NEtx03BC;-C(R)C(NEt2)NN(CPh2)x03BC;-C(R)C(NEt)]

The diiron ynamine complex [Fe₂(CO)₇{μ-CR)C(NEt₂)}] (1:R=Me,2:R = C₃H₅.3:R=SiMe₃.4:R = Ph) reacts at room temperature with diphenyldiazomethane Ph₂CN₂, in hexane to yield complexes [Fe₂(CO)₆{C(R)C(NEt₂)N (NCPh₂)] (5a:R=Me,6a:R=C₃H₅.7a R=SiMe₃.8a:R=Ph) resulting from the insertion of the terminal nitrogen atom into the Fe=C carbene bond. Insertion the second nitrogen atom and formation of compounds [Fe₂(CO)₆zμ-C(R)C(NEt₂)NN(CPh₂)}] (5b:R=Me,6b:R=C₃H₅,7b:R=SiMe₃,8b:R=Ph) is observed when compounds5a-5a are treated in refluxing hexane. Transformation of compoundsa tob is also obtained at room temperature within a few days. All compounds were identified by their¹H NMR spectra. Compounds6a, 7a, 8a, and8b were characterized by single crystal X-ray diffraction analyses. Crystal data: for6a: space group = P2₁/n,a=12.853(1) A,b=24.800(7) A,c=8.947(6) A,β=99.29(3)°,Z=4, 2227 rellectionsR=0,038; for7a: space group=Pl,a=ll.483(4) A,b=14.975(4) A,c = 17.890(8) A,α = 82.80(3)°,β=94.29(7)°,γ=85.42(2),Z = 4, 5888 reflectionR = 0.035: for8a: space group = Pcab.a = 31.023(8) A.b=20.137(1) A.c=9.686(2) A.Z=8. 1651 reflections,R=0.071; for8b: space group=P2₁/n,a=21.459(4),b=10,100(3) A,c=28,439(8) A,ß=103.86(4)°,Z=8. 2431 reflections.R=0.057.     

Trimethylphosphine complexes of tungsten(O) and (IV). X-ray crystal structures of trimethylphosphine tris (phenylacetylene) tungsten(O); bis(trimethylphosphine) tetrakis (methylisocyanide) tungsten(O), and oxodichlorotris (trimethylphosphine) tungsten (IV)

The reduction of WCl₄(PMe₃)₃ by sodium amalgam in presence of phenylacetylene gives W(PMe₃)(PhCCH)₃ (A). Reduction in presence of methylisocyanide gives W(PMe₃)₂(MeNC)₄ (B), while in presence of excess PMe₃ in tetrahydrofuran under hydrogen, WH₂Cl₂(PMe₃)₄ (C) is formed. The reaction of WCl₂(PMe₃)₄ with methanol in tetrahydrofuran gives mixtures of WH₂Cl₂(PMe₃)₄ and WOC1₂(PMe₃)₃ (D).The structures of A, B, and D have been determined by X-ray diffraction.     

Crystal structure of tris(ethylenediamine)cobalt(III) (aqua)hexachloromercurate(II) chloride [Co(En)3]2[Hg2(H2O)Cl6]Cl4

The compound [Co(En)₃]₂[Hg₂(H₂O)Cl₆]Cl₄ (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna2₁) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)₃]³⁺ cations of opposite chirality). [Hg₂(H₂O)Cl₆]^2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl₄]^2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H₂O)Cl₂] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å).     

A Series of monohapto pyrazolates of iridium(I) and iridium(III)

The reaction of trans-IrCl(CO)L₂ with pz^?1 gives trans-Ir(pz-N)(CO)L₂, where pzH is 3,5-dimethyl-, 3,5-dimethyl-4-nitro- or 3,5-bis(trifluoromethyl)-pyrazole, and L = PPh₃. The nitrogen atom not involved in coordination can be protonated with HBF₄ to give the corresponding [Ir(CO)L₂(pzH-N]⁺ cation. The iridium(I) pyrazolates undergo oxidative addition, yielding Ir(H)₂(pz-N)(CO)L₂ species, while gaseous HCl cleaves the IrN bond, affording IrH(Cl)₂(CO)L₂. The iridium(I) derivatives can be obtained in several solid-state forms, each characterized by a slightly different CO stretching frequency. The presence of a monodentate pyrazolato ligand in trans-Ir(3,5-(CF₃)₂pz-N)(CO)L₂, in the form with ν(CO) at 1975 cm^?1, is supported also by an X-ray crystal structure determination. The compound crystallizes in the monoclinic system, space group P2₁/n, with cell dimensions a = 21.106(6), b = 19.700(5), c = 9.437(2) Å, and β = 94.34(2)° and Z = 4.     

Synthesis and crystal structure of aqua(2.2.2-cryptand)(perchlorato-O)lead(II) diaqua(2.2.2-cryptand)lead(II) tris(perchlorate)

A mixed complex aqua(2.2.2-cryptand)(perchlorato-O)lead(II) diaqua(2.2.2-cryptand)lead(II) tris(perchlorate), [Pb(2.2.2-Crypt)(CIO₄)(H₂O)]⁺ [Pb(2.2.2-Crypt)(H₂O)₂]²⁺ (ClO ₄ ^? )₃, is synthesized and studied by X-ray diffraction analysis. The crystals are orthorhombic: space group Pbca, a = 19.118 Å, b = 15.360 Å, c = 39.020 Å, Z = 8. The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.089 for 7712 reflections (CAD-4 automated diffractometer, λMoK _α radiation). In each of the two complex cations of the host-guest type in the structure, the Pb²⁺ cation is coordinated by all the eight heteroatoms (6O + 2N) of the cryptand ligand and by two O atoms of the water molecule and ClO ₄ ^? anion or by two O atoms of two water molecules. In the crystal, alternating complex cations and ClO ₄ ^? anions are linked into infinite chains (along the z axis) through interionic hydrogen bonds O-H···O-Cl.     

Synthesis, crystal structure, and structural features of hexa(isothiocyanate)chromates(III) of lanthanum(III) and neodymium(III) complexes with nicotinic acid

[M(C₅H₅NCOO)₃(H₂O)₂][Cr(NCS)₆] · nH₂O complexes, where M = La and n = 2 (1) or M = Nd and n = 1 (2), were synthesized by reacting M(NO₃)₃ (M = La, Nd, K₃[Cr(NCS)₆]) and nicotinic acid (C₅H₅NCOO) in aqueous solution. Their structure was established by IR spectroscopy and X-ray diffraction analysis. The crystals of complexes 1 and 2 are monoclinic, space group P2₁/n, Z = 2; for complex 1, a = 9.66800(10) Å, b = 25.7662(2) Å, c = 15.4843(2) Å, β = 106.4700(10)sO, V = 3698.99(7) ų, ρ_calcd = 1.761 g/cm³; for complex 2, a = 9.53120(10) Å, b = 25.5166(4) Å, c = 15.3843(3) Å, β = 104.9450(10)sO, V = 3614.96(10) ų, ρ_calcd = 1.779 g/cm³. Different hydrate compositions of the given compounds may be due to the specific features of intermolecular interactions in their structures.     

Crystal structure of oxo(diperoxo)bipyridylmolybdenum(VI)

Yellow oxo(diperoxo)bipyridylmolybdenum(VI), C₁₀H₈MoN₂O₅, M_r = 332.1 crystallizes in the monoclinic space group P2₁/n, a = 6.261(3), b = 12.726(1) c = 13.752(3)A, β = 91.84(2)°, V = 1095.2(5)A³, Z = 4, D_c = 2.014(1) g/cm³, MoKα(λ = 0.7107A), μ = 11.8 cm^?1, T = 22(1)°C, R = 0.034, ωR = 0.040, number of reflections in least squares (F₀ > 2σ(F₀)) = 1125. The molybdenum coordination (distorted trigonal bipyramidal) is as in the corresponding chromium complex, C₁₀H₈CrN₂O₅ which has closely similar bond angles but is not isomorphous. The difference in MoN_apex and MoN_eq bond distances (2.312(5) and 2.199(5)A) is similar to that in the CrN_apex and CrN_eq distances (2.23(2) and 2.11(2)A). The MO distances for each peroxo ligand (ave. 1.910(2) and 1.950(2)A) are significantly different and slightly longer than those in the chromium complex as is the OO distance of 1.459(6)A. The latter is indicative of greater negative charge on the O₂ ligands, approaching that of O^2?₂ in the molybdenum complex.     

Reaction between magnesium chloride and iron(III) chloride in tetrahydrofuran. The crystal structure of Di-μ-chlorodichloroiron(II) tetrakis(tetrahydrofuran)magnesium(II)

The direct reaction between magnesium chloride and iron(III) chloride in tetrahydrofuran (THF) yields the [MgCl(THF)₅][FeCl₄] complex (I). It is unstable and in reacting with THF undergoes reduction to produce the complex FeCl₂(μ-Cl)₂Mg(THF)₄ (II). Crystals of (II) are orthorhombic, space group Pbcn, with a = 9.18(1) b = 16.30(2) c = 15.85(1)Å. The structure was solved by the heavy atom method and refined by least squares to R = 0.053 for 1194 observed diffractometer data. The molecule is heterobimetallic with an Fe…Mg distance 3.455(3)ǎ and the Fe and Mg atoms are bridged by two Cl atoms.     

Synthesis and crystal structure of divaleratobis(nicotinamide)copper(II)

A copper(II) valerate complex with nicotinamide (L) [CuL₂(C₄H₉COO)₂] (I) has been synthesized and studied by IR spectroscopy and thermogravimetry. The crystal structure has been determined. The crystals of 1 are monoclinic, a = 11.297(1) Å, b = 6.666(1) Å, c = 16.873(2) Å, b = 108.50(1)°, V = 1204.9(3) ų, Z = 2, space group P2₁/c. The structural units of the crystal of I are centrosymmetric tetragonal bipyramidal (4+2) complex molecules. The equatorial positions of the bipyramid are occupied by trans-arranged pairs of O (Cu-O, 1.973 Å) and N (Cu-N, 2.006 Å) atoms, and the axial positions are occupied by the second O atoms of the valerate anions located at longer distances (Cu-O, 2.506 Å). The supramolecular associates formed in the crystal are layers of hydrogen-bonded complexes. The disordered hydrocarbon “tails” of the valerate groups point toward the interlayer space.     

Some palladium(II) and platinum(II) lead bonded complexes

Complexes of the type M(PPh₃)₂(PbPh₃)₂ [M = Pd, (Ia) and Pt, (Ib)] have been prepared by oxidative addition of hexaphenyldilead to M(PPh₃)₄. The compound Pt(PPh₃)₂(PbPh₃)₂, (Ib), slowly decomposes in dichloromethane to give cis-Pt(PPh₃)₂(PbPh₃)Ph, (II). which can also be obtained by treating (Ib) with the stoichiometric amount of LiPh. Reaction of Pt(PPh₃)₄ with hexamethyldidead gives the complex Pt(PPh₃)₂(PbMe₃)Me directly.The MPb bonds are easily cleaved by bromine, iodine and hydrogen bromide. The X-ray structure of (II) has been determined using three-dimensional counter data and refined by the least-square method (R = 0.07). The crystals are monoclinic a = 22.501, b = 10.502, c = 24.120 Å, β = 113.43°, space group P2₁/c with Z = 4. The complex exhibits a cis configuration, with the coordination around the platinum atom essentially square-planar: the PtPb and PtC(phenyl)bond lengths are 2.698(1) and 2.055(3)Å, respectively.