Bhavesh Patel

Synthesis, spectroscopic and structural studies on six- and eight-coordinate phosphane and arsane complexes of titanium(IV) halides

The six-coordinate complexes [TiX4(L-L)] [X = Cl or Br; L-L = Ph2PCH2PPh2, Ph2P(CH2)(2)PPh2, Ph2P(CH2)(3)PPh2, o-C6H4(PPh2)(2), o-C6H4(PMe2)(2), Ph2As(CH2)(2)AsPh2, o-C6H4(AsMe2)(2) or MeC(CH2AsMe2)(3)] and the eight-coordinate complexes [TiX4(L-L)(2)] [L-L = a-C6H4(PMe2)(2) or o-C6H4(AsMe2)(2)] have been prepared and characterised by solution H-1 and P-31(H-1) NMR spectroscopy, IR and UV/Visible spectroscopy and microanalyses. The crystal structures of [TiCl4{o-C6H4(PMe2)(2)}], [TiCl4{o-C6H4(PMe2)(2)}(2)], [TiBr4{o-C6H4(PMe2)(2)}(2)], [TiBr4{o-C6H4(AsMe2)(2)}(2)] and [TiBr4{MeC-(CH2AsMe2)(3)}] are described and permit detailed comparisons to be made between the six- and eight-coordinate species and between the phosphane and arsane species. The crystal structure of the zwitterionic [TiCl5(Ph2PCH2PHPh2)] is also reported.

Rhodium complexes with secondary phosphine and phosphinite ligands and the crystal structures of [(PPh2OH)2(PPh2O)Rh(μ-Cl)3Rh(PPh2OH)(PPh2O)2] and [(PPh2OH)(PPh2O)Cl(NCMe)Rh(μ-Cl)2Rh(PPh2OH)(PPh2O)Cl(NCMe)] · 2thf

Abstract RhCl3·3H2O reacts with ca six molar equivalents of PPh2H or PCy2 in EtOH solution under a N2 atmosphere and in the presence of excess NH4PF6 to yield [RhCl2(PPh2H)4]Pf6 or [RhCl2(PCy2H)4]PF6 respectivley as yellow solids. 31P{1H} NMR spectroscopy shows the presence of the trans isomer only in chloro-carbon solutions, with JRhP ca 80 Hz. Upon standing a solution of trans-[RhCl2(PPh2H)4]PF6 in a MeCH/thf mixture results in the production of yellow crystals of [(PPh2OH)(PPh2OCl(NCMeRh(μ-Cl)2Rh(rmPPh2OH)(PPH2O)Cl(NCMe)]·2thf, the structure of which shows an edge-bridge bioctahedral arrangement with d ( Rd … Rh ) = 3.74 A . The NCMe ligands to the terminal Cl ligands, while the PPh2O and PPh2O− ligands are trans to the bridging Cl ligands. The crystal structure of the triply-bridged dimer [(PPh2OH)2(PPh2O)Rh(μ-Cl)3Rh(PPh2OH)(PPh2O)2] has aslo been determined, showing a face-sharing bioc-tahedral arrangement, with d ( Rh … Rh ) = 3.39 A . Both dinuclear species show significant POH…OP hydrogen-bonding interactions.

Synthesis, properties and crystal structures of 6-, 7- and 8-coordinate Zr(IV) and Hf(IV) complexes involving thioether and selenoether ligands

A series of 6-, 7- and 8-coordinate complexes of the form [MCl4(L–L)] (M = Zr, Hf; L–L = MeE(CH2)2EMe), [ZrCl4([9]aneS3)] and [MCl4{MeE(CH2)2EMe}2] (E = S or Se) has been obtained in moderate to high yield by reaction of [MCl4(Me2S)2] with one (or three for the 1 ∶ 2 M ∶ L–L species) molar equivalents of L–L in rigorously anhydrous CH2Cl2. The poorly soluble products have been characterised by far IR spectroscopy, diffuse reflectance UV-Vis spectroscopy and microanalyses. 1H NMR data are reported for certain systems, although in the majority of cases the very poor solubility prevented useful NMR experiments. The crystal structures of six representative examples, the distorted octahedral [ZrCl4(Me2S)2] and [HfCl4{MeSe(CH2)2SeMe}], the metallocyclic [(ZrCl4)2{μ-MeS(CH2)3SMe}2], the flattened dodecahedral [ZrCl4{MeS(CH2)2SMe}2] and [HfCl4{MeS(CH2)2SMe}2] and the 7-coordinate [ZrCl4([9]aneS3)] are also described. The crystal structure of [Me2SCH2Cl]2[Zr2Cl10], formed during reaction of [ZrCl4(Me2S)2] with MeSe(CH2)2SeMe in CH2Cl2 is also presented.

Coordination networks derived from antimony(III) halide complexes with thio- and seleno-ether ligation

Antimony(III) halides form highly unusual infinite one- or two-dimensional networks when coordinated to dithio- or diseleno-ether ligands or macrocyclic selenoethers. The structures adopted are contrasted with those observed for related bismuth(III) species.

Silver(I) complexes with the mixed P/O donor ligand Ph2P(CH2)2O(CH2)2O(CH2)2PPh2 (L1) and the crystal structures of [Ag(L1)](CF3SO3), [Ag2(L1)3](CF3SO3)2 and [Ag(L1)(NO3)]

Abstract The Ag(I) salts AgY (Y=ClO4, CF3SO3, NO3, Cl or I) react with one molar equivalent of the diphosphinodiether ligand Ph2P(CH2)2O(CH2)2O(CH2)2PPh2 (L1) to give 1:1 species of stoichiometry Ag(L1)Y. The structures of these species have been investigated in solution by 31P NMR spectroscopy and for [Ag(L1)](ClO4), [Ag(L1)](CF3SO3) and [Ag(L1)(NO3)] in the solid state by single crystal X-ray diffraction. In particular, the 107Ag–P and 109Ag–P coupling constants provide a convenient method for identifying the solution speciation, especially for the occurrence of anion coordination in the nitrate and halide complexes. The conclusions from the NMR spectroscopic studies are also consistent with the solid state structures. Addition of a further equivalent of L1 to [Ag(L1)](CF3SO3) results in a very significant drop in the Ag–P coupling constants, indicative of higher P-coordination at Ag(I), now involving three P-donor atoms. This conclusion is also borne out by a crystallographic study on [Ag2(L1)3](CF3SO3)2 which shows a dinuclear cation with one chelating L1 and one bridging L1 ligand coordinated to each metal centre, giving a distorted trigonal planar geometry.

Synthesis, properties and structures of eight-coordinate zirconium(IV) and hafnium(IV) halide complexes with phosphorus and arsenic ligands

Eight-coordinate [MX(4)(L-L)(2)] (M = Zr or Hf; X = Cl or Br; L-L = o-C(6)H(4)(PMe(2))(2) or o-C(6)H(4)(AsMe(2))(2)) were made by displacement of Me(2)S from [MX(4)(Me(2)S)(2)] by three equivalents of L-L in CH(2)Cl(2) solution, or from MX(4) and L-L in anhydrous thf solution. The [MI(4)(L-L)(2)] were made directly from reaction of MI(4) with the ligand in CH(2)Cl(2) solution. The very moisture-sensitive complexes were characterised by IR, UV/Vis, and (1)H and (31)P NMR spectroscopy and microanalysis. Crystal structures of [ZrCl(4)[o-C(6)H(4)(AsMe(2))(2)](2)], [ZrBr(4)[-C(6)H(4)(PMe(2))(2)](2)], [ZrI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] and [HfI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] all show distorted dodecahedral structures. Surprisingly, unlike the corresponding Ti(iv) systems, only the eight-coordinate complex was found in each system. In contrast, the ligand o-C(6)H(4)(PPh(2))(2) forms only six-coordinate complexes [MX(4)[-C(6)H(4)(PPh(2))(2)]] which were fully characterised spectroscopically and analytically. Surprisingly the tripodal triarsine, MeC(CH(2)AsMe(2))(3), also produces eight-coordinate [MX(4)[MeC(CH(2)AsMe(2))(3)](2)] in which the triarsines bind as bidentates in a distorted dodecahedral structure. There is no evidence for seven-coordination as found in some thioether systems.