Metal-metal interactions in homo- and hetero-metallic complexes containing d0, d8 and d10 metal ions : spectroscopic and theoretical studies

by Xia, Baohui

Abstract (Summary)
(Uncorrected OCR) Abstract of thesis entitled


Submitted by

Xia Baohui

for the degree of Doctor of Philosophy at The University of Hong Kong

in September 2002

The structural and spectroscopic properties of dinuclear [M2Cu~dcpm)2(CN)d, [M2(u-dmpm)z(CN)41 (M = Pt, Ni, dcpm = bis(dicyclohexylphosphino)methane, dmpm = bis(dimethylphosphino)methane) and mononuclear trans-[M(PCY3)2(CN)z] (M = Pt, Ni, PCY3 = tricyclohexylphosphine) complexes and theoretical investigations of model compounds are reported. The UV-vis absorption bands at 337 nm for [Pt2(udcpm)z(CN)41 and 328 urn for [Pt2(u-dmpm)z(CN)41 in CH2Ch were assigned to I (5dcr * ~6pcr) electronic transitions originating from Pt(II)~ Pt(H) interactions. A resonance Raman spectroscopic study of [Pt2(Jl~dcpm)2(CN)4] verified this metalmetal interaction. For dinuclear nickel(Il) complexes [Nh(,u-dcpm)2(CN)4] and [NhCu-dmpm)2(CN)4], neither spectroscopic data nor theoretical calculations suggested the presence of Ni(II)-Ni(II) interactions. The intense absorption bands at A > 320 nm in the UV-vis spectra of dinuc1ear Ni(II) complexes were assigned to d~d transitions.

structural and spectroscopic properties of dinuclear [Pd2W?cpm);z(CN),t], [Pd2(u-dmpm)2(CNhl and mononuclear trans-[Pd(PCY3h(CN)2]. detivativeswet?examined. The absorption bands at Iv > 270 llID in the dinuclear cOtllplexesWere shown to have 4d(J*~5p(J electronic transition character. CIS calculations indicated that the two low-lying dipole-allowed electronic transitions .. in. [}.)<,HUtH2PCthPJ-!z)2(CN)4] at 303 and 289 nm were the combination of many transitions, consistent with the results from resonance Raman spectroscopy.theiCl;l.19ulated interaction energy curves for the skewed dimer [trans-Pd(PH3h(CN)zh >were

attractive at MP2 level.

The structural and spectroscopic properties of a series of heterodinuclear.d8 ? dlo metal complexes containing dS Pt(II), Pd(II), or Ni(II) and dlo Au(I), Ag(I),or Cu(!) metal ions with the dcpm bridging ligand have been studied. X-ray crystal analysis showed that the metal"'metal distances in these heteronuclear complexes are shorter than the sum of their van der Waals radii. The UV-vis absorption spectra of[PtMVzdcpm)2(CNht (M Au, Ag, and Cu) display absorption bands associatedwithrnet@l?metal interactions. The resonance Raman spectra confirmed the assignm?ltii<.)f 1 [nd(r*~(n+l )Pcr] electronic transitions for the lowest energy dipole-allowed absorption bands in [PtM(u-dcpm)2(CNht (M = Au, Cu). Theoreticalcalculations gave an attractive interaction energy curve for the skewed (transAu(PH3)2 +] dimer. The interaction energy of Pt(II)-Au(I) at the MP2 ?level wa.s calculated to be ca. 0.45 e V.

The syntheses, X-ray crystal structures and spectroscopic propertiesofaseriesof clusters containing dO Mo(VI) or W(VI) and dlO Au(I), Ag(I), or Cu(I).metatioIlsiare described. Clusters of [Cl14(dcpm)4(MoS4)](Cl04)2 and [Cll4(dcpm)4(WS4)](Cl()4)2 feature unusual 16-membered [CU4PSC4] metallamacrocycles .. They?.hipitlovvenergy absorption bands at ~562 and 467 nm respectively which are assigned to MMCT transitions, and they are emissive both in the solid state and in.solution.Both electron acceptors and donors can quench the emission of [Cll4(dcpm)4(WS4)f+.

Bibliographical Information:


School:The University of Hong Kong

School Location:China - Hong Kong SAR

Source Type:Master's Thesis

Keywords:metal complexes ions raman spectroscopy


Date of Publication:01/01/2003

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