Ligating properties of tertiary phosphine/arsine sulphides or selenides. Part VII. Synthesis and characterisation of palladium(II) complexes with some mono- and ditertiary phosphine sulphides or selenides

Summary Palladium(II) halides react with triphenylphosphine sulphide or selenide, 1,1-methylenebis(diphenylphosphine sulphide or selenide) (MDPS or MDPSe), 1,3-trimethylene-bis-(diphenylphosphine selenide) (PDPSe) or tetramethyldiphosphine disulphide (TMDPS) forming complexes [PdBr₂ · 2L], [2PdBr₂ · 3L] (L=Ph₃PS or Ph₃PSe), [PdX₂ · L] (X=Cl, L =PDPSe; X=Br, L=MDPS or MDPSe; X=Cl or Br, L=TMDPS) and [3PdBr₂ · 2TMDPS]. Characterisation and stereochemical assignments have been made through elemental analyses, i.r., far i.r. and electronic spectra, magnetic susceptibility and molar conductance data and tga studies. Bidentate ligand complexes have higher thermal stability than the monodentate ligand complexes. Chelation or bridging modes of the bidentate ligands have been demonstrated.     

The catalytic reactions of triethyl- and triethoxy-silane with unsaturated sulphides

The hydrosilylation of mono- and di-alkenyl sulphides of the type RS(CH₂)_nCH=CH₂ (R = C₂H₅, CH₂=CH, CH₂=CHCH₂, C₃H₇, n = 0, 1 and 4) by triethyl- and triethoxy-silane, catalyzed by H₂PtCl₆·6 H₂O, (Ph₃P)₃RhCl and (PhCN)₂PdCl₂·Ph₃P, has been studied. The addition of hydrosilane to the double bond of alkenyl sulphide leads to a mixture of two isomeric monoadducts. The hydrosilane can cleave the C---S bond of the initial sulphides giving the corresponding derivatives of thiosilanes, X₃SiS(CH₂)_nCH=CH₂ (X = C₂H₅, C₂H₅O). Hydrosilylation of alkenyl sulphides is accompanied by some side reactions such as dehydrocondensation, reduction and polymerization. The effect of the catalyst nature, the structure of hydrosilane and alkenyl sulphide on the reaction route has been investigated.     

Dihalodicarbonylruthenium(II)-bis(tertiaryphosphine chalcogenide) complexes

Summary Reactions of 1,1-methylene bis(diphenylphosphine oxide or sulphide) (dpmO₂ or dpmS₂) and 1-(diphenylphosphinoethyl)-2-diphenylphosphine sulphide (dpePS) with dihalodicarbonylruthenium(II) in EtOH gave 1:1 (L:M) complexes of stoichiometry: Ru(CO)₂X₂L₂ (L = dpmO₂, dpmS₂ or dpePS; X = Cl or Br), which were characterized by elemental analysis and i.r. spectroscopy. The spectra reveal that: (a) the carbonyls occupy octahedral cis-positions, and (b) dpmS₂ shows a higher coordination shift than does dpePS, probably due to the better Lewis basicity of the Ph₂P moiety as compared to the Ph₂P(S) moiety in the ligands. Cis-octahedral geometries are inferred from these studies.     

Rhodium(I) carbonyl complexes of triphenylphosphine chalcogenides and their catalytic activity

Rhodium(I) carbonyl complexes [Rh(CO)₂ClL] where L = Ph₃PO, Ph₃PS and Ph₃PSe, were synthesized and characterized by elemental analysis, i.r. and by ¹H-, ¹³C- and ³¹P-n.m.r. spectroscopy. The vBD;(CO) band frequencies in the complexes follow the order: Ph₃PO > Ph₃PS > Ph₃PSe, in keeping with the hard/soft nature of the interactions. The complexes undergo oxidative additions with electrophiles such as MeI, PhCH₂Cl and I₂ to give, e.g. [Rh(CO)(COMe)ClIL] which react with PPh₃ to give trans-[Rh(CO)Cl(PPh₃)₂]. The catalytic activity of the [Rh(CO)₂ClL] complexes in carbonylation of MeOH is higher than that of the well-known [Rh(CO)₂I₂]⁻ species. This revised version was published online in June 2006 with corrections to the Cover Date.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2-Methyl-benzoselenazole

The following zinc(II), cadmium(II) and mercury(II) complexes of 2-methyl-benzoselenazole (L) have been prepared and studied by conductometric and i.r. methods: MLX₂ (M ? Cd, Hg, X ? Cl, Br, I), ML_1.5X₂ (M ? Zn, X ? ClO₄(4 H₂O); M ? Hg, X ? NO₃, ClO₄), ML₂X₂ (M ? Zn, X ? Cl, Br, I, NO₃; M ? Cd, X ? NO₃, ClO₄). The ligand is N-bonded. All the anions are coordinated.     

Synthesis and spectroscopic studies of phenyllead halide and thiocyanate adducts with hexamethylphosphoramide

Hexamethylphosphoramide (HMPA) adducts of the type Ph₃PbX·HMPA (X=Cl, Br, I, and NCS), Ph₂PbX₂·2HMPA (X=Cl, Br, and I), and Ph₂PbX₂·HMPA (X=Br and I), have been prepared and characterized by infrared, Raman, mass, and ³¹P nmr spectroscopy. Molecular weight and infrared solution data show that Ph₃PbX·HMPA adducts dissociate in benzene, the degree of dissociation being NCS«Cl<Br<I. The thiocyanate adducts Ph₃PbNCS·HMPA and Ph₂Pb(NCS)₂·2HMPA have v(CN) and v(CS) frequencies in the solid state, and v(CN) frequencies and absorptivities in benzene solution consistent with N-bonded thiocyanate in the solid state and in benzene solution. Vibrational frequencies are reported in the range 260 to 80 cm⁻¹ and assignments are made for v(Pb-X), v(Pb-O0, and v(Pb-NCS) modes. The 1:1 adducts Ph₃PbX·HMPA are monomeric and trigonal bipyramidal, whereas the 1:2 adducts Ph₂PbX₂·2HMPA are monomeric and cis-octahedral and the Ph₂PbX₂·HMPA appear to be halogen bridged polymers with lead six-coordinate. Coordination of HMPA causes a small upfield change in ³¹P chemnical shift values, and ²J(Pb-P) values vary with X in the order: NCS>I-Br>Cl for Ph₃PbX·HMPA adducts. Corresponding tin and lead adducts are compared with respect to mode of adduct formation.     

Synthesis and conformational studies of palladium(II) complexes containing [PhP(O)NP(E)Ph]− (E=S or Se)

The ligands [Ph₂P(O)NP(E)Ph₂]⁻ (E=S I; E=Se II) can readily be complexed to a range of palladium(II) starting materials affording new six-membered Pd–O–P–N–P–E palladacycles. Hence ligand substitution reaction of the chloride complexes [PdCl₂(bipy)] (bipy=2,2′-bipyridine), [{Pd(μ-Cl)(L–L)}₂] (HL–L=C₉H₁₃N or C₁₂H₁₃N), [{Pd(μ-Cl)Cl(PMe₂Ph)}₂] or [PdCl₂(PR₃)₂] [PR₃=PPh₃; 2PR₃=Ph₂PCH₂CH₂PPh₂or cis-Ph₂PCH=CHPPh₂] with either I (or II) in thf or CH₃OH gave [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(bipy)]PF₆, [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(L–L)], [Pd{Ph₂P(O)NP(E)Ph₂-O,E}Cl(PMe₂Ph)] or [Pd{Ph₂P(O)NP(E)Ph₂-O,E} (PR₃)₂]PF₆ in good yields. All compounds described have been characterised by a combination of multinuclear NMR [31 P{1 H} and 1 H] and IR spectroscopy and microanalysis. The molecular structures of five complexes containing the selenium ligand II have been determined by single-crystal X-ray crystallography. Three different ring conformations were observed, a pseudo-butterfly, hinge and in the case of all three PR₃ complexes, pseudo-boat conformations. Within the Pd–O–P–N–P–Se rings there is evidence for π-electron delocalisation.     

Cobalt(II), nickel(II) and copper(II) with 2-substituted benzimidazole complexes

Summary Complexes of stoichiometries M(Acbim)₂X₂·nH₂O and M(Bzbim)₂X₂·nH₂O (M = Co, Ni or Cu; Acbim = 2-acetylbenzimidazole, Bzbim = 2-benzoylbenzimidazole; X = Cl, Br, NO₃ or ClO₄; n = 0, 1 or 2) have been prepared and characterised by spectroscopic and physicochemical methods. The ligands coordinate through carbonyl oxygen and tertiary nitrogen.     

Synthesis of aurocyanide and auricyanide complexes of phosphines,phosphine sulfides and phosphine selenides,and their characterization by IR,far-IR,UV solution,and solid-state NMR spectroscopic methods

A series of aurocyanide and auricyanide complexes of phosphines, phosphine sulfides, and phosphine selenides were synthesized. These new complexes have the general formula [L _n Au(CN) _m ], where L could be Cy₃P, (2-CN-Et)₃P, Me₃PS, Et₃PS, Ph₃PS, Me₃PSe, or Ph₃PSe. Auricyanide was reacted with L at 1?:?2 ratio. Products were characterized using elemental analysis, melting point, UV, IR, far-IR solution, and solid-state NMR spectroscopy. Phosphine ligands cause gold(III) reduction to gold(I); less redox tendency was found for phosphine sulfides and phosphine selenides. Tri-coordinate complexes [L₂AuCN] were produced from phosphine ligands with gold-tetracyanide. IR and UV spectroscopic methods were used to identify gold oxidation state in the synthesized complexes.     

Novel M(II)–Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu, Ni, Co) and HgCl2

A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)₂HgCl₂ (4), [Co(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.61H₂O (5) and [Ni(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.77H₂O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂(M=Cu(II), Co(II), Ni(II)), with HgCl₂. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) ų, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P , with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) ų, Z=1. Compound 6 also crystallized in the triclinic space group P , with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) ų, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg₂Cl₂ linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂ (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl₂ depending on the metal cation contained within them.     

Synthese und Eigenschaften von [Ph2(Carb)P]AlCl4 (Carb = 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐yliden) – ein stabiler Carben‐Komplex des dreiwertigen Phosphors [1]

Synthesis and Properties of [Ph₂(Carb)P]AlCl₄ (Carb = 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) – a Stable Carbene Complex of Trivalent Phosphorus [1] 2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene ( 7 , Carb) reacts with chlorodiphenylphosphane to give the cationic phosphane [Ph₂(Carb)P]Cl ( 10 ) which is transferred to the more stable salt [Ph₂(Carb)]AlCl₄ ( 13 ) on treatment with AlCl₃. The cationic phosphane selenide [Ph₂(Carb)PSe]AlCl₄ ( 14 ) is obtained from 13 and selenium. Spectroscopic and structural data indicate [Ph₂(Carb)P]⁺ to be a cationic analogue of Ph₃P. The X‐ray structure of 13 is reported.     

Hydrosilylation in the presence of platinum(II) and rhodium(I) complexes with chloride and trichlorostannate(II) anions

Hydrosilylation of allyl butyl ether and acetophenone with 1,1,3,3-tetramethyldisiloxane in the presence of [Pt(LL′)XY] and [Rh(Ph₃P)₃X] (L, L′ = cod, dmso, Py, Bn₂S, Ph₃P; X, y = Cl, SnCl₃) was studied.     

Synthesis and characterization of new HgS nanoparticles prepared by Hg(II)-triazole-3-thiol as precursor

Nine Hg(II) complexes, [Hg(DiphtS)₂(L-L)](2–7) {where, HDiphtS = 4,5-diphenyl-1,2,4-triazole-3-thiol; L-L = bis(diphenylphosphino)ethane (dppe) (2); 1,3-bis(diphenylphosphino)propane (dppp)(3); 1,4-bis(diphenylphosphino)butane (dppb)(4); 1,1′-bis(diphenylphosphino)ferrocene (dppf)(5); 2,2′-bipyridine (Bipy)(6) and 1,10-phenanthroline (Phen)(7) } or [Hg(DiphtS)₂(L)₂] (8–9) {where L = triphenylphosphine (Ph₃P) (8) and triphenylphosphine sulphide (Ph₃PS) (9)}, have been prepared form the reaction of [Hg(DiphtS)₂](1) with phosphine or amine as co-ligands. Then characterized by the IR, NMR (¹H and ³¹P) spectroscopy, elemental analysis, molar conductivity. The results supported the monodentate behaviour of HDiphtS ligand in all complexes (1–9) in anion form through the sulfur atom. Complexes 1, 2 and 6 have been used as single source precursors for the preparation of ethylene-diamine capped HgS-nanoparticles. Powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM), have been used to characterize the HgS nanoparticles.     

Preparation and properties of palladium(II) and rhodium(I) complexes containing bidentate phosphine sulphide and selenide ligands

Summary The synthesis and properties of cationic complexes of general formula [ML₂{CH₂(Ph₂PE)₂}]BF₄, where M = Pd^II and Rh^II, L₂ = ³-MeC₃H₄, {P(O)(OR)₂}₂H (R = Me, Et), COD, (CO)₂, (CO)PPh₃ and E = S, Se are described. The methylene proton of the coordinated phosphine sulphide or selenide ligands react with strong bases as BuLi in n-hexane or NaH in THF, to give neutral complexes of the type [ML₂{CH(Ph₂PE)₂}], where M = Pd^II, Rh^I; L₂ = ³-MeC₃H₄, COD and E = S, Se. The complexes have been characterized by elemental analyses, molar conductivities, i.r., ¹H n.m.r. and ³¹P{¹H} n.m.r. spectroscopy.     

Studies of organotin(IV)-orthoquinone systems

The primary process in the reaction of hexaphenylditin with various substituted orthoquinones (Q) is shown to involve attack by the quinone at a phenyl ligand. The intermediate thus formed decomposes to yield Ph₃Sn(SQ^·), where S(Q^·−) is the corresponding semiquinonate. Rearrangement of these species in solution gives rise to biradicals, while intramolecular electron transfer may lead to the formation and precipitation of Ph₂Sn(CAT), where CAT²⁻ is the corresponding substituted catecholate. The identification of these processes depends in part on electron paramagnetic resonance spectroscopy. The reaction of Ph₃SnCl or Ph₂SnCl₂ with Na(TBSQ^·) (TBSQ^·−=3,5-di-tert-butyl-orthobenzosemiquinonate) results in the formation of Ph₂Sn(TBSQ^·), which can undergo redistribution and intramolecular electron transfer, so that the solution chemistry of these latter systems is similar to that of the products of the Sn₂Ph₆+Q reaction.     

Co(II), Ni(II) and Cu(II) Complexes with 1-(4-Hydroxyphenyl)-1H-1,2,4-Triazole

New complexes of Co(II), Ni(II), and Cu(II) with 1-(4-hydroxyphenyl)-1H-1,2,4-triazole (L) of the composition ML₂(H₂O)₂(NO₃)₂ · nH₂O (M = Co(II), n = 3; M = Ni(II), n = 0; M = Cu(II), n = 0) were synthesized and studied by photoelectron and IR spectroscopy, magnetochemistry, thermogravimetry, and X-ray powder diffraction analysis. The type of _eff(T) relationship suggests that paramagnetic centers in the Co(II) chloride and Cu(II) nitrate and bromide complexes are involved in antiferromagnetic exchange interactions. The exchange energy values were estimated by the molecular field method.     

Bis(2,6-dimethoxyphenyl) sulfide, selenide and telluride, and their derivatives

2,6-Dimethoxyphenyl derivatives of sulfur, selenium, and tellurium, such as ΦEEΦ, Φ₂E, ΦSeH, [MeΦ₂E]X (X=MeSO₄, ClO₄), Φ₂EO · xH₂O, [Φ₂EOR]ClO₄, [Φ₂EOH]ClO₄ (R=Me, Et), Me₂SnCl₂ · 2Φ₂EO (E=S, Se) [Φ=2,6-(MeO)₂C₆H₃; E=S, Se, Te] have been prepared, and their properties compared with common phenyl derivatives. The reaction rates of Φ₂E with dimethyl sulfate and butyl bromide increased in the order E=S<Se<Te, which were compared with those of Ph₃M and Φ₃M, M=P>As>Sb. These reactivities are parallel with the electrochemical oxidation potentials reported for Ph₂E and with the first ionization potentials reported for Ph₃M. The rate of Φ₂Te was faster than that of Ph₃P and slightly faster than that of Φ₃Sb. From the reactivity of [Φ₂E-Me]⁺ salts with nucleophiles, the E⁺–Me bond strengths were estimated to increase in the order E=Se<S<Te. The reaction rates of Φ₂EO with dimethyl sulfate increased in the order E=S<Se<Te, and the respective rate of Φ₂EO was faster than that of Φ₂E. The origins of these reactivities and bond strengths are discussed.     

Zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethyl-pyrimidine-2(1H)-one

The following zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (L) have been prepared and investigated by conductometric,IR and Raman methods: MX₂L₂ (M = Zn, X = Cl, Br(CHCl₃, I(CHCl₃, CF₃COO; M = Cd, X = Cl, Br CF₃COO; M = Hg, X = Cl, CF₃COO), Cd₂I₄L₃, Hg₃X₆L₂ (X = Cl, Br), Hg₃X₆L₄(X = Br, I), MX₂L₄·6H₂O (M = Zn, Cd, X = CIO₄, BF₄; M = Hg, X = CIO₄. The ligand is principally bonded through the unprotonated nitrogen atom and in some complexes also through the carbonylic oxygen atom. The zinc halide complexes are tetrahedrally coordinated, the trifluoroacetate ion is coordinated as a monodentate ligand.     

Metal complexes of hybrid oxygen-arsenic ligands—III : Complexes of 2-tertiary arsinobenzoic acids with zinc(II), cadmium(II) and mercury(II). Discovery of a novel chelating system

This paper describes the preparation of the halogeno complexes, HgX₂(o-R₂AsC₆H₄CO₂H) (X = Cl, Br, I, and R = Et; X = Br, I, and R-C₆H₁₁) and the carboxylate complexes, M(o-R₂-AsC₆H₄CO₂)₂nL(M = Cd, R = Et, C₆H₁₁ and n = O; M = Zn; R = Et; nL = H₂O; M = Zn, R = C₆H₁₁, nL = 3H₂O; M = Hg, R = p-tolyl, nL = 2H₂O; M = Hg, R = Me, Ph; C₆H₁₁ and nL = EtOH). The structures already reported for the halogeno complexes with R = Ph, Me, p-tolyl and X = Cl, Br, I, have been revised on the basis of detailed scrutiny of the IR spectral data and all these complexes have been divided into four structural types out of which three retain the acid dimer unit of the free ligand. In the carboxylate complexes the lowering of ν_s, CO₂ band and the marginal change in the ν_as CO₂ band with respect to those of the corresponding ligand sodium salts have been attributed to the existence of a novel resonating chelating system with the possibility of having a ring current.     

Vibrational spectroscopy and solid-state MAS NMR studies of mercury(II) acetate complexes [Hg(X)OAc]: Crystal structure of [Hg(CN)OAc]

The syntheses of [Hg(X)OAc] (OAc=acetate; X=CN, Cl, Br, I, SCN) are reported, and the crystal structure of the cyano complex has been determined. The asymmetric unit contains two [Hg(CN)OAc] molecules which show almost linear C–Hg–O bonding (Hg–C=2.019(13), 2.016(11) Å; Hg–O=2.067(9), 2.058(8) Å; C–Hg–O=176.0(4), 172.3(5)°), with only one of the two acetate oxygen atoms bound directly to the mercury atom. Secondary HgO and HgN contacts in the range 2.6–2.8 Å are about 0.2 Å shorter than the secondary HgO contacts in the corresponding X=Ph complex. The ν(HgX) and ν(HgO) modes have been assigned in the IR and Raman spectra of [Hg(X)OAc] (X=CN, Cl, Br, I, SCN); these spectra show that the complexes have structures with essentially linear O–Hg–X bonding, similar to that of the cyanide. Solid-state ¹⁹⁹Hg MAS NMR spectra have been recorded for HgX₂ (X=CN, Cl) and [Hg(X)OAc] (X=Me, Ph, CN, Cl, SCN), and spinning sideband analysis has been used to determine the ¹⁹⁹Hg shielding anisotropy and asymmetry parameters Δσ and η. A semi-empirical method for the calculation of the local paramagnetic contribution to the shielding is given, and a linear relationship between Δσ and the isotropic shielding σ_iso which is predicted by this model for linear HgXY species is found to be obeyed reasonably well by the experimental data for HgX₂ and [Hg(X)OAc]. The same method is used to analyse the effects of secondary bonding on the ¹⁹⁹Hg shielding parameters. The ¹³C MAS NMR spectrum of [Hg(SCN)OAc] shows ²J(¹⁹⁹Hg¹³C) and ³J(¹⁹⁹Hg¹³C) coupling to the acetate carbon atoms, with magnitudes similar to those found previously for Hg(OAc)₂. The CN carbon signals in Hg(CN)₂ and [Hg(CN)OAc] are split into 2:1 doublets due to residual dipolar coupling to the quadrupolar ¹⁴N nucleus.