Stephen G. Murray

Bidentate group VB chelates : XVI. The preparation of o-phenylenebis(diphenylstibine) and attempts to prepare cis- and trans-1,2-bis(diphenylstibino)ethylene

Abstract o -Phenylenebis(diphenylstibine) (sbsb) has been obtained from sodium diphenylstibide and o -bromophenyldiphenylstibine. The failure of other routes to this compound, and of attempts to prepare ethylenic distibines, are discussed.

Coordination complexes containing multidentate ligands. Part X. The reaction of divalent cobalt, nickel, and palladium salts with open-chain tetrathioethers, α,ω-bis(methylthioalkylthio)alkanes. The effect of chelate chain length on donor and spectral properties

Abstract The aliphatic open-chain tetrathioethers, 1,2-bis(2-methylthioethylthio)ethane, 1,3-bis(2-methylthioethylthio)propane, 1,2-bis(3-methylthiopropylthio)ethane, and 1,3-bis(3-methylthiopropylthio)propane have been synthesised and reacted with divalent metal salts. They form complexes of the type [Co(ligand)I2], [Ni(ligand) X2] (X = Cl, Br, I), and [Pd2(ligand)X4] (X = Cl, Br, I), but not all ligands form each type of complex, and the donor properties of these tetrathioethers are discussed in terms of the chain lengths between the sulphur atoms. Calculation of in-plane ligand field in the trans- [Ni(ligand)X2] complexes indicates that the field strengths of the tetrathioethers changes from the solid state to solution and are also dependent on the nature of the coordinated halide.

Synthesis, properties, and multinuclear (1H, 13C, 77Se) nuclear magnetic resonance studies of selenoethers containing two or more selenium atoms

A convenient synthesis of MeSeLi from MeLi and Se8 in tetrahydrofuran (THF) has been used to prepare the bis-selenoethers MeSe[CH2]nSeMe (n= 1,2,3,6, or 12) and cis-MeSeCHCHSeMe. PhSe[CH2]nSePh (n= 1–3) and cis-PhSeCHCHSePh have been prepared from PhSe–, itself produced from Ph2Se2 and LiAIH4–THF or sodium hydroxymethanesulphinate. The bis-selenoethers o-C6H4(SeR)2(R = Me or Ph) were obtained from R2Se2 and benzyne. The syntheses of (RSeCH2)3CMe (R = Me or Ph), (MeSeCH2)4C, and (MeSeCH2CH2CH2)2Se are also described. The 1H, 13C, and 77Se n.m.r. spectra of these selenoethers have been recorded, and the chemical shifts and coupling constants (nJSe–H, nJSe–C) are discussed in terms of structures. Mass spectra of the selenoethers have been recorded and the principle fragmentation modes identified.

Bidentate group vb ligands. Part XIII. Divalent cobalt, nickel, and palladium complexes of 1,2-bis(methylphenylarsino)ethane and 1,3-bis(methylphenylarsino)propane. Stoichiometric and structural effects of chelate chain length

Abstract Thirtyfour complexes of 1,2-bis(methylphenylarisino)ethane (dase) and 1,3-bis(methylphenylarsino)propane (dasp) have been characterised. Interesting differences are observed in the complexing properties of these chelates. Thus, with cobalt(II) halides [Co(dase) 2 ][CoX 4 ], which contain planar cations, and pseudotetrahedral [Co(dasp)X 2 ] are obtained. Nickel (II) halides form planar [NiLX 2 ] complexes with dase, but with dasp form [Ni(dasp)X 2 ] n (X = Cl, Br) which are pseudooctahedral in the solid state and planar in solution, and the pseudotetrahedral [Ni(dasp)I 2 ]. The [Ni(dasp) 2 X] ClO 4 are trigonal bipyramidal in the solid state (X = Cl, Br, I, NCS), but in solution [Ni(dasp) 2 (NCS)] + appears to be square pyramidal, whilst the [Ni(dase) 2 X] ClO 4 are square pyramidal in both the solid state and solution. The planar [Ni(dasp)(NCS) 2 ] complex differs from the analogous dase species by losing ligand on recrystallisation to form the dimeric Ni 2 (dasp) 3 (NCS) 4 moiety. Planar [PdLX 2 ] (L = dase, dasp, X = Cl, Br, I) species are formed, but no [PdL 2 X] + complexescould be isolated. In the solid state [PdL(NCS)(SCN)] complexes are formed, and the dase species isomerises to [Pd(dase)(SCN) 2 ] in dichloromethane. An attempt is made to relate the structural differences in the complexes to the chain length of the chelates.

Synthesis and properties of Group 5B ligand analogues of o-phenylenebis(dimethylarsine), o-C6H4(EMe2)(E′Me2) where E, E′= P, N, As, or Sb

Lithium dimethylphosphide prepared from lithium and PMe2Ph in tetrahydrofuran reacts with o-dichlorobenzene to produce o-phenylenebis(dimethylphosphine). Similar reactions using the appropriate o-bromophenyl derivatives o-C6H4Br(Y)(Y = NMe2, AsMe2, or SbMe2) yield o-C6H4(PMe2)Y. o-Phenylenebis(dimethylstibine) is best prepared from (o-bromophenyl)dimethylstibine and Na[SbMe2]. Preparations for the other members of the series, o-C6H4(AsMe2)(SbMe2), o-C6H4(AsMe2)(NMe2), and o-C6H4(SbMe2)(NMe2), and for (o-methoxyphenyl)- and (o-methylthiophenyl)-dimethylphosphine o-C6H4(PMe2)Z (Z = OMe or SMe) are reported. The 1H and 31P n.m.r. and mass spectra of the ligands, intermediates, and quaternary derivatives are reported and discussed.

The coordination chemistry of molybdenum and tungsten. Part V. Open-chain tetrathioether complexes of molybdenum(IV) and (V) and tungsten(IV) and (V)

Abstract The tetrathioethers α, ω-bis(methylthioalkylthio)alkanes, CH 3 S(CH 2 ) n S(CH 2 ) m S(CH 2 ) n SCH 2 (n = m = 2; n = 2, m = 3; n = 3, m = 2, n = m = 3, ligand), yield seven-co-ordinate [MCl 4 (ligand) (M = Mo, W), seven-coordinate [WoCl 3 (ligand)] in which the thioethers act as tridentate ligands, and six-coordinate [MoOCl 3 ) 2 (ligand)] in which the ligand acts in a tetraligate bimetallic manner. 2-5-Dithiahexane (dth) similarly yielded [MCl 4 (dth)(RCN)] and [MoOCl 3 (dth)]. The electronic, infrared and electron paramagnetic resonance spectral properties of these complexes are reported and discussed.

Co-ordination complexes containing multidentate ligands. Part 12. Nickel(II)–bismuth(III) co-ordination in nickel(II) complexes of tris(o-dimethylarsinophenyl)bismuthine and tris(3-dimethylarsinopropyl)bis-muthine

Two potentially quadridentate chelating ligands containing bismuth atoms have been synthesised: tris(o-dimethyl-arsinophenyl) bismuthine (L1) and tris(3-dimethylarsinopropyl)bismuthine (L2). Reaction of L1 with nickel(II) salts produces the essentially square-pyramidal [NiL1X]+(X = Cl, Br, or I) and [Ni2L13][ClO4]4 species, whilst L2 forms the trigonal-bipyramidal [NiL2(OH2)][ClO4]2. The resulting structures are discussed in terms of the structures of the ligands.

Complexes of bidentate group VB chelates : XIX. Mass spectral studies on some methyl-substituted bidentate group VB donor ligands☆

Abstract The fragmentation patterns of seven bidentate and two tridentate Group VB donor ligands are reported. For these methyl-substituted ligands the initial fragmentation is essentially loss of methyl radicals. Phenyl, but not methyl, migration occurs for the bis(phenylmethylarsino)alkanes, but methyl migration is evident in the all aliphatic bidentate chelates. The tridentate ligands PhE(CH2CH2CH2AsMe2)2 (E = P, As) show similar fragmentation routes, but are more complex. The long chain diarsine, Me2As(CH2)12AsMe2, exhibits a tendency to cyclise and lose C2H4 fragments progressively.

trans-Chelation of 1,12-bis(dimethylarsino)dodecane to palladium(II)

Abstract The diarsine ligand, 1,12-bis(dimethylarsino)dodecane, reacts with tetrachloropalladate(II) in ethanol/dichloromethane to form in highly yield the monomeric [Pd(ligand)Cl 2 ] complex containing the trans -chelating diarsine.

Trans-bidentate behaviour of a potentially tetradentate ligand to palladium(II) and platinum(II)

The ligand 1,3-bis(3-dimethylarsinopropylthio)propane, L, forms MLX2 (M  Pd, Pt; X  Cl, Br, I), which are pentacoordinate [MLX]X in the solid state and in nitromethane and planar trans-[MLX2], containing a trans-chelating diarsine ligand in dichloromethane; these are the first examples of a potentially tetradentate ligand acting as a trans-chelating bidentate.