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Richard J. Puddephatt

Publications and source records attributed to Richard J. Puddephatt.

7 recordsLinked to original sources
PubMed1999

Photoelectron Spectra of Trimethylphosphine-Substituted Tungsten Carbonyls: Ligand Field Effects, Ligand Additivity Effects, and Core-Valence Ionization Correlations.

High-resolution broad-scan gas-phase photoelectron spectra using synchrotron radiation (including valence, inner valence, and core levels) are reported for a series of trimethylphosphine-substituted tungsten carbonyls: W(CO)(6), W(CO)(5)PMe(3), cis-W(CO)(4)(PMe(3))(2), trans-W(CO)(4)(PMe(3))(2), and fac-W(CO)(3)(PMe(3))(3). The inner valence and core level spectra are interpreted by comparison with the published spectra of W(CO)(6) and other metal carbonyls. High-resolution valence level spectra of these complexes are also obtained by He I radiation. Fine structure, resulting from spin-orbit splitting, ligand field splittings, and vibrational coupling is resolved in the spectra of both W 5d and W 4f regions. Ligand field splittings on both the W 5d and W 4f levels increase in the order W(CO)(6) approximately fac-W(CO)(3)(PMe(3))(3) < W(CO)(5)PMe(3) </= cis-W(CO)(4)(PMe(3))(2) < trans-W(CO)(4)(PMe(3))(2). For the first time, the phosphorus 2p spin-orbit components of the phosphine complexes have been resolved. The binding energies (or ionization potentials) in the spectra of both W 5d valence level and W 4f core level regions are shifted almost linearly to lower energy with each successive step of ligand substitution. The shift per phosphine substitution is 0.66 +/- 0.03 eV for the W 5d ionizations and 0.76 +/- 0.03 eV for the W 4f ionizations (DeltaE(valence)/DeltaE(core) = 0.86 +/- 0.03). Similar linear shift trends are also found in the phosphorus 2p core level and phosphorus valence "lone-pair" ionizations. These data confirm the ligand additivity model predictions for these complexes.

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PubMed1999

Synthesis of Metallacycles by Oxidative Addition of Sn-S, Sn-Se, Sn-Te, and Ge-Te Containing Precursors to Platinum(II).

The first metallacycles formed by oxidative addition of tin-sulfur, tin-selenium, tin-tellurium, and germanium-tellurium bonds to platinum(II) are reported. In particular, the ring compounds [(R(2)SnE)(3)], where R = Me, Ph and E = Se, Te, and the new compound [(Me(2)GeTe)(3)], react with [PtMe(2)(bu(2)bpy)] (bu(2)bpy = 4,4'-di-tert-butyl-2,2'-bipyridine) to give the new organoplatinum(IV) metallacycles [PtMe(2)(R(2)SnE)(2)(bu(2)bpy)] and [PtMe(2)(Me(2)GeTe)(2)(bu(2)bpy)], respectively. The tin-containing metallacycles complexes can undergo exchange of either the R(2)Sn or the E groups by reaction with [(R'(2)SnE)(3)] or [(R(2)SnE')(3)], respectively, to give the corresponding new metallacycles of general formula [PtMe(2)(R(2)SnE-R'(2)SnE)(bu(2)bpy)] or [PtMe(2)(R(2)SnE-R(2)SnE')(bu(2)bpy)]. The isostructural series of complexes [PtMe(2)(Ph(2)SnE)(2)(bu(2)bpy)] with E = S, Se, and Te have been characterized by X-ray structure determinations. It is shown that (119)Sn NMR is a useful method of structure determination for these metallacyclic compounds.

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PubMed1998

Heteronuclear Hexaplatinum Cluster Complexes: Structure as a Function of Electron Count.

The 84-electron hexaplatinum cluster complex [Pt(6)(&mgr;-CO)(6)(&mgr;-dppm)(3)], 1, dppm = Ph(2)PCH(2)PPh(2), reacts in a 1:2 molar ratio with either 0-electron metalloligands LM(+) (L = Ph(3)P, M = Cu, Ag, Au; L = iPr(3)P, M = Au) or InX(3) (X = Cl, Br) or 2-electron metalloligands Tl(+) and Hg to give the corresponding 84-electron clusters [Pt(6)(&mgr;(3)-ML)(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)](2+) or [Pt(6)(&mgr;(3)-InX(3))(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)] or 88-electron clusters [Pt(6)(&mgr;(3)-Tl)(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)](2+) and [Pt(6)(&mgr;(3)-Hg)(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)], respectively. The mercury cluster is oxidized by CH(2)I(2) to give the known 86-electron cluster [Pt(6)(&mgr;(3)-HgI)(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)]. Reaction of 1 with [Ir(CO)(4)](-) occurs in a 1:1 ratio only to give the 98-electron anionic cluster [Pt(6){&mgr;(3)-Ir(CO)(2)}(&mgr;-CO)(6)(&mgr;-dppm)(3)](-), which reacts with [Ph(3)PAu](+) to give [Pt(6){&mgr;(3)-Ir(CO)(2)}(&mgr;(3)-AuPPh(3))(&mgr;-CO)(6)(&mgr;-dppm)(3)]. The new cluster complexes are characterized by NMR and IR spectroscopies, and [Pt(6)(&mgr;(3)-AuPiPr(3))(2)(&mgr;-CO)(6)(&mgr;-dppm)(3)](2+) is also characterizedby an X-ray structure determination.

Journal Article↗
PubMed1996

Electronic Structures of Copper(I) and Silver(I) beta-Diketonate Complexes.

The valence electronic structures of [Cu(hfac)L] (hfac = CF(3)C(O)CHC(O)CF(3); L = PMe(3), CNMe), [Ag(hfac)(PMe(3))], and [Ag(fod)(PEt(3))] (fod = t-BuC(O)CHC(O)C(3)F(7)) have been studied by recording their photoelectron spectra and by performing Xalpha-SW calculations on the model compounds [M(dfm)(PH(3))] (dfm = HC(O)CHC(O)H; M = Cu, Ag) and [Cu(dfm)(CNH)]. For the copper complexes, the spectra were recorded between 21 and 160 eV using He I, He II and synchrotron radiation; while, for the silver complexes, He I and He II, spectra were recorded. Assignments were made by comparison of experimental and calculated values of band energies, and, for the copper complexes, by similar comparison of experimental and theoretical branching ratios as a function of photon energy. For the silver complexes, a more limited comparison of band intensities in the He I and He II spectra was made. In analogous compounds, it is shown that the binding energies follow the sequence Ag 4d > Cu 3d, with an energy difference of almost 2 eV.

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