Electrodeposition from supercritical fluids.

Recent studies have shown that it is possible to electrodeposit a range of materials, such as Cu, Ag and Ge, from various supercritical fluids, including hydrofluorocarbons and mixtures of CO2 with suitable co-solvents. In this perspective we discuss the relatively new field of electrodeposition from supercritical fluids. The perspective focuses on some of the underlying physical chemistry and covers both practical and scientific aspects of electrodeposition from supercritical fluids. We also discuss possible applications for supercritical fluid electrodeposition and suggest some key developments that are required to take the field to the next stage.

(Ethanol-O)tris(nitrato-O,O')bis(triphenylphosphine oxide-O)cerium(III).

The title compound, [Ce(NO(3))(3)(C(2)H(6)O)(C(18)H(15)OP)(2)], contains discrete molecules with nine-coordinate Ce atoms having all nitrate groups bonded as symmetrical bidentate ligands [Ce-O(P) 2. 369 (2) and 2.385 (2), Ce-O(N) 2.549 (3)-2.596 (3) and Ce-O(Et) 2. 515 (3) A].

Synthesis, spectroscopic, and structural studies on transition metal complexes involving homoleptic tripodal selenoether and telluroether coordination.

The reaction of [MCl2(NCMe)2] (M = Pd or Pt) with 2 molar equiv of MeC(CH2ER)3 (E = Se, R = Me; E = Te, R = Me or Ph) and 2 molar equiv of TlPF6 affords the bis ligand complexes [M(MeC(CH2ER)3)2][PF6]2. The crystal structure of [Pt(MeC(CH2SeMe)3)2][PF6]2 (C16H36F12P2PtSe6, a = 12.272(10) A, b = 18.563(9) A, c = 15.285(7) A, beta = 113.18(3) degrees, monoclinic, P2(1)/n, Z = 4) confirms distorted square planar Se4 coordination at Pt(II), derived from two bidentate tripod selenoethers with the remaining arm not coordinated and directed away from the metal center. Solution NMR studies indicate that these species are fluxional and that the telluroether complexes are rather unstable in solution. The octahedral bis tripod complexes [Ru(MeC(CH2SMe)3)2][CF3-SO3]2 and [Ru(MeC(CH2TePh)3)2][CF3SO3]2 are obtained from [Ru(dmf)6][CF3SO3]3 and tripod ligand in EtOH solution. The thioether complex (C18H36F6O6RuS8, a = 8.658(3) A, b = 11.533(3) A, c = 8.659(2) A, alpha = 108.33(2) degrees, beta = 91.53(3) degrees, gamma = 106.01(2) degrees, triclinic, P1, Z = 1) is isostructural with its selenoether analogue, involving two facially coordinated trithioether ligands in the syn configuration. NMR spectroscopy confirms that this configuration is retained in solution for all of the bis tripod Ru(II) complexes. These low-spin d6 complexes show unusually high ligand field splittings. The hexaselenoether Rh(III) complex [Rh(MeC(CH2SeMe)3)2][PF6]3 was obtained by treatment of [Rh(H2O)6]3+ with 2 molar equiv of MeC(CH2SeMe)3 in aqueous MeOH in the presence of excess PF6- anion, while the iridium(III) analogue [Ir(MeC(CH2SeMe)3)2][PF6]3 was obtained via the reaction of the Ir(I) precursor [IrCl(C8H14)2]2 with the selenoether tripod in MeOH/aqueous HBF4. NMR studies reveal different invertomers in solution for both the Rh and Ir species. The Cu(I) complexes [Cu(MeC(CH2ER)3)2]PF6 were obtained from [Cu(NCMe)4]PF6 and tripod ligand in CH2Cl2 solution. The corresponding Ag(I) species [Ag(MeC(CH2TeR)3)2]CF3SO3 (R = Me or Ph) were obtained from Ag[CF3SO3] and tripod telluroether. In contrast, a similar reaction with 2 molar equiv of MeC(CH2SeMe)3 afforded only the 1:1 complex [Ag(MeC(CH2SeMe)3)]CF3SO3. The structure of this species (C9H18AgF3O3SSe3, a = 8.120(3) A, b = 15.374(3) A, c = 14.071(2) A, beta = 93.86(2) degrees, monoclinic, P2(1)/n, Z = 4) reveals a distorted trigonal planar geometry at Ag(I) derived from one bidentate selenoether and one monodentate selenoether. These units are then linked to adjacent Ag(I) ions to give a one-dimensional linear chain cation.

The relationship of some copper (II) complexes of facultative tetrathioethers to the coordination environment in the "blue" copper proteins.

The facultative potentially tetradentate thioether ligands 1,2-bis(methylthioethylthio)ethane (2,2,2), 1,3-bis(2-methylthioethylthio)propane (2,3,2) and 1,2-bis(3-methylthiopropylthio)ethane (3,2,3) react with copper(II) salts to form Cu2(2,2,2)Cl4, Cu3(ligand)X6 (ligand = 2,3,2 and 3,2,3 X = Cl; ligand = 2,2,2 2,3,2 and 3,2,3 X = Br), and Cu(ligand)(ClO4)2. The stoichiometry and structures of these complexes are discussed in terms of the steric demands of the ligand and the nature of the halide. The [Cu(2,3,2)(ClO4)] ClO4 and [Cu(3,2,3)(ClO4) [ClO4 complexes have electronic spectra which exhibit the intense 600 nm band characteristic of the "blue" copper proteins. In fact, the spectrum of [Cu(2,3,2)(ClO4)]ClO4 is very similar to that of pseudomonas aeroginosa azurin.