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Lead(II) carboxylate soaps of two fatty acids, palmitic (C15H31COOH) and stearic acids (C17H35COOH), and a dicarboxylic acid, azelaic acid (HOOCC7H14COOH), have been synthesised and characterised by FTIR spectroscopy. These acids are all encountered in aged traditional oil paint, the azelaic acid resulting from the oxidative degradation of unsaturated fatty acids in the oil. Lead(II) azelate synthesised by hydrothermal methods was characterised by single crystal structure determination. This has a 3D polymeric structure with lead(II) ions linked by carboxylate bridges to form an infinite stack of (PbO4)(n) units. These layers are connected to adjacent layers by an infinite number of parallel C(CH2)(7)C chains arranged perpendicularly to the stacks. The lead(II) ions display an unusual 7-fold coordination. The first direct evidence that the 'protrusions' encountered in aged traditional lead-containing oil paints contain lead soaps is reported. Their mechanism of formation is discussed.

Reactions of bis(N-phenylsalicylideneiminato)aluminium(III)di(mu-isopropoxo)di(isopro poxo) aluminium(III), [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(OPri)(2) (1) with simple and internally functionallized oximes in 1:1 and 1:2 molar ratios in refluxing anhydrous benzene yield binuclear complexes of the type, [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(ON=CRR')(OPri) and [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(ON-CRR')(2) [where R=R'=CH3; R=CH3, R=C4H3S-2, C4H3O-2 and C5H4N-2], respectively containing aluminium(III) atoms in six- and four-coordination sites. All these binuclear complexes are characterised by elemental analysis, molecular weight measurements and spectroscopy [IR and NMR(H-1, C-13 and Al-27)]. Reaction of bis(N-phenylsalicylideneiminato)(isopropoxo)aluminium(III) with 2-acetylthiophenyloxime in 1:1 molar ratio in refluxing anhydrous benzene, yields a novel heteroleptic compound, [C6H4O{CH=N(C6H5)}](2)Al{ON=C(CH3)C4H3S-2} (10). The crystal structure of [C6H4O {CH =N(C6H5)}](2)Al {ON =C(CH3)C4H3S-2} . CH2Cl2 shows five-coordination around the aluminium(III) atom.

Arachno-2-metallatetraboranes, [M(CO)2L2(B3H8)] (M=Re, L=PPh3, P(C6H4Cl-4)3, P(C6H4OMe-4)3, P(CH2Ph)3; M=Mn and Re, L=1/2dppm, 1/2dppp, 1/2dppb, 1/2dppf; M=Mn, L=1/2dppe), have been synthesised from reactions of [NBu4][B3H8] with fac,cis-[MBr(CO)3L2] under photolytic conditions. These compounds were characterised by NMR (1H, 11B, 31P) and IR spectroscopy. [Mn(CO)2(dppe)(B3H8)] and [Re(CO)2(dppf)(B3H8)] were further characterised by single-crystal X-ray diffraction studies. These studies confirmed molecular Cs symmetry and a trans dicarbonyl arrangement. Similar reactions with the bis(monodentate) organophosphine complexes, mer,trans-[MnBr(CO)3L2], did not yield isolatable arachno-2-metallatetraboranes.

Four amido-pyrrole cleft anion receptors bearing one or two ferrocene reporter groups have been synthesised and crystallographically characterised. The receptors contain either a non-conjugated (1 and 3) or conjugated (2 and 4) link between the anion binding amido-pyrrole unit and the ferrocene reporter groups. The anion binding affinities and electrochemical behaviour of the receptors in the absence and presence of anions have been studied by 1H NMR titration techniques and cyclic voltammetry using a Pt microdisc working electrode, respectively.

A series of dinuclear organo-functionalised stibine and arsine ligands incorporating a range of hard, soft and pi-donor moieties have been synthesised from the reactions of Cl2Sb(CH2)(3)SbCl2 and Cl2AsCH2AsCl2 with a range of organolithium reagents. The X-ray structures of 1,3-[(PhCdropC)(2)Sb](2)(CH2)(3) (1), As(CdropCPh)(3) (2), R2AsCH2AsR2 [R = Me(3)SiCdropC, 3; (Me3Si)(2)N, 4; and 2-SPy 5] have been determined. Compound 5 associates into pseudo dimers as a result of intermolecular pi-pi stacking between the pyridyl groups on one end of two separate diarsine molecules. Whereas the bridging unit remains intact during the syntheses of 1 and 3-5, the formation of the mononuclear trisacetylide species 2, involves the unexplained cleavage of the bridging methylene unit.

The reaction between Ph3SbBr2 and sodium salt of internally functionalized oximes in 1:2 molar ratio in refluxing anhydrous benzene afforded [Ph3Sb{ON=C(R)Ar}(2)] [R = CH3, Ar = C5H4N-2(1), C4H3S-2(2) C4H3O-2(3); R = H, Ar = C5H4N-2(4), C4H3S-2(5) and C4H3O-2(6)]. Treatment of (1) and (4) with 1 equiv. of Ph3SbBr2 yields the redistribution product [Ph3Sb(Br){ON=C(R)Ar}]. Controlled hydrolysis of (1) and (4) affords a species [Ph3Sb(OH){ON=C(R)Ar}]. All these complexes have been characterized by the elemental analyses, IR and NMR spectroscopic studies and in the case of I by single crystal X-ray diffraction studies. The structure of I features trigonal bipyramidal geometry around the antimony with the axial positions occupied by the two oxygen atoms of the oxime group [O(1)-Sb(1)-O(l)' 172.78(7)degrees] and equatorial positions by the phenyl groups.

Reactions between the bulky ligand tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) and HgX2 (X = Cl, Br, 1) in ethanol have been described. Complexes of stoichiometry (P:Hg) 1:1, 2:1 and 2:3 have been isolated and their spectral features discussed. The structures of the 1:1 bromide and iodide show them to be discrete monomers unlike most other tertiary phosphine analogues. Additionally a complex of stoichiometry TMPP(HgI2)(2) has been prepared and characterised structurally as (TMPP)HgI(mu-I)HgI(mu-I)(2)HgI(mu-I)HgI(TMPP).

yThe reactions of N-(2-chloroethyl)benzamide and N-[3-bromopropyl]phthalimide with ArTe- Na+ generated in situ by borohydride reduction of Ar2Te2, have resulted in N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L-1) and N-[2-(4-methoxyphenyltelluro)propyl] phthalimide (L-2) respectively. The L-1 and L-2 both exhibit characteristic H-1 and C-13 NMR spectra. The single crystal structures of L-1 and L-2, the latter as a mixed crystal with (LH2)-H-2 are determined by X-ray diffraction (XRD). The Te-C(alkyl) bond length is 2.140(8)/2.149(4) Angstrom and longer than Te-C(aryl), 2.107(8)/2.123(5) Angstrom. The complexes having stoichiometries [PdCl2(L-1)] (1), [PtCl2(L-1)](2), [(Phen)Pd(L-1)](ClO4)(2) (3), [(DPPE)Pd(L-1)](ClO4), (4) and [RuCl2(L-2)(2)] (5) were synthesized and characterized by elemental analyses, conductance and molecular weight measurements, NMR (H-1 and C-13) and FT-IR spectra. The deshielding of CH2Te ( similar to 0.2 ppm in H-1 NMR and up to 22 ppm in C-13{H-1} NMR) and NH signals (upto 0.8 ppm in H-1 NMR) of 1 -4, with respect to those of free L-1 indicates that L-1 coordinates with Pd-Pt(II) as a (Te, N) ligand. The CH2Te/CH2N signals in H-1 and C-13 NNIR spectra of 5 appear deshielded (0.8/0.14 and 20/8 ppm, respectively), when compared with those of free L2, indicating ligation of L-2 via Te and N.

The crystal structures of two lead containing porphyrins are described. Structure 1 contains unprecedented stacks of three metalloporphyrins. Each structure shows disorder of the Pb atoms which are situated out of the mean plane of the porphyrin ring.

[SnR2Cl2] (R=Me, tBu) react with OPPh2C6H4SH in the presence of NaOEt affording mononuclear derivatives [SnR2(OPPh2C6H4S)2] (1, 2) with two units of the oxide of the thiophenylphosphine. The loss of one of such units is achieved by the reaction of 1 and 2 with HCF3SO3 or HClO4 giving rise to complexes with the formula [SnR2(OPPh2C6H4S)]A (A=CF3SO3, ClO4) (3a–b, 4a–b). The crystal structure of [SntBu2(OPPh2C6H4S)]ClO4 (4b) has been determined by X-ray diffraction.

Treatment of bis(dipbenylphosphino)methane disulfide (dppmS) or bis(diphenylphosphino)ethane disulfide (dppeS) with diiodine in dichloromethane yields the adducts dppmS .I-4 1 and dppeS .I-4 2, respectively, whose structures have been solved by X-ray crystallography. Compounds 1 and 2 consist of discrete molecular units containing bent P-S-I and linear S . . .I-I geometries that can be interpreted in terms of donation of electron density from sulfur to diiodine. Consistent with this interpretation, the P-S bonds are lengthened compared to the unco-ordinated phosphine sulfides, and the I-I bonds are lengthened compared to unco-ordinated diiodine. Both compounds can therefore be described as 'charge-transfer' complexes. The two S . . .I-I moieties in 1 are inequivalent having markedly different bond lengths and angles. In 2 both S . . .I-I moieties are identical. The structural features of 1 and 2 are in accordance with Raman and P-31 CP MAS NMR data.

The reactions of Na2[Fe(CO)4] with 3,4-toluenedithiol and 1,3-propanedithiol at room temperature give the dinuclear complexes [Fe2(CO)6{μ-S CCHCHC(CH 3 )CHC S}] (1) and [Fe2(CO)6(μ-SCH2CH2CH2S)] (2), respectively. Compounds 1 and 2 both react with triphenylphosphine at ambient temperature to give [Fe2(CO)5{μ-S CCHCHC(CH 3 )CHC S}(PPh3)] (3) and [Fe2(CO)5(μ-SCH2CH2CH2S)(PPh3)] (4), respectively. The compounds have been characterized by spectroscopic data together with single crystal X-ray diffraction studies for 1 and 3. The toluenedithiolate anion acts as a bidentate ligand with both the sulfur atoms forming symmetrical bridges across the metalmetal bond.

Reactions of C2Cl3HgX (X = C2Cl3, Cl, Br) with the potential bidentate ligands, bis(diphenylphosphino)methane, 2,4'-bipyridyl, 4,4'-bipyridyl and 2,2'-dipyridyl disulfide(PySSPy), in a 2:1 molar ratio have been studied and the thermal and infrared spectral characteristics of the products have been examined. Complexes were isolated for (C2Cl3)(2)Hg and C2Cl3HgCl in all cases apart from between (C2Cl3)(2)Hg and the diphosphine. The diphosphine and 2,2'-dipyridyl disulfide formed 1:1 complexes (7, 6) with C2Cl3HgCl, whereas with (C2Cl3)(2)Hg the latter ligand formed [{(C2Cl3)(2)Hg}(2)(PySSPy)] (3) which on standing formed C2Cl3HgSPy (12). 4,4'-Bipyridyl and 2,4'-bipyridyl differed in the stoichiometry of the isolated complexes. (C2Cl3)(2)Hg formed 1:1 complexes (1, 2) with both ligands whereas C2Cl3HgCl formed a 1:1 complex (4) with the former ligand but a 1:2 complex (5) with the latter. All four ligands caused disproportionation of C2Cl3HgBr with resulting isolation of the mercury(II) bromide complexes (8-11). The structure of [(C2Cl3)(2)Hg (4,4'-bipyridyl)] (1) shows that only one nitrogen is weakly coordinated to mercury so that C-Hg-C is approximately linear in the monomeric structure but there are four intramolecular chlorines closer to mercury than the sum of the van der Waals radii. The C-Hg-S angle in [C2Cl3Hg(2-pyridyl thiolate)] (12) is only slightly distorted from linearity due to secondary bonding to nitrogen. There are two weak intramolecular contacts between mercury and chlorine and two intermolecular mercury-sulfur contacts to form pairs of molecules which form double chains along the b axis. [HgBr2(2,2'-dipyridyl disulfide)] (10) is polymeric and contains four-coordinate mercury with the ligand bridging between mercury atoms via coordination to nitrogen.

Reactions of HgX2 (X=Cl, Br, I) with the very bulky tertiary phosphine, tris(2,6-dimethoxyphenyl)phosphine (DMPP), in either a 1:1 or a 1:2 ratio, result in only the isolation of the 1:1 adducts. The structures adopted in the solid state are markedly influenced by the steric requirement of the phosphine. In contrast to the 1:1 triphenylphosphine adducts reported earlier, which are dimeric, the DMPP mercury(II) chloride and bromide complexes are weakly linked dimers while the iodide is the first example of a mercury iodide–phosphine complex with a monomeric distorted trigonal-planar arrangement around mercury. All three complexes contain secondary interactions with the o-methoxy groups.

The reaction of [Os3(CO)10(MeCN)2] with 2-methyl-2-thiazoline at ambient temperature results in the C–H activation of the methyl substituent of the heterocyclic ligand and this gives the new compound [(μ-H)Os3(CO)10(μ-η2-CH2 C  NCH 2 CH 2 S ] (8) in 55% yield. Compound 8 undergoes decarbonylation and a further C–H bond activation by thermolysis at 98°C or by treatment with trimethylamine-N-oxide to give the dihydrido cluster [(μ-H)2Os3(CO)9(μ-η2-CH C  NCH 2 CH 2 S ] (9) in 45% yield. Both complexes have been characterized by elemental analyses, IR and 1H NMR spectroscopy, together with X-ray crystallography for 8.