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Solid state NMR studies and chemical shift calculations of a gold(I) complex with a diphosphacyclobutadiene cobaltate
Thomas Wiegand1, Hellmut Eckert, Stefan Grimme
1Institut für Physikalische Chemie and Graduate School of Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany.
Abstract:
The (31)P and (13)C solid state nuclear magnetic resonance spectra of a neutral gold(I) complex with bis(diphosphacyclobutadiene) cobaltate anions, [Au{Co(P2C2tPent2)2}2(PMe3)2], are reported. Complete (31)P resonance assignments have been derived from saturation transfer, radio-frequency driven recoupling (RFDR) and RTOBSY experiments and confirmed further by ab-initio calculations of magnetic shielding tensors by density functional theory, with consideration of relativistic effects. Coordination of the diphosphacyclobutadiene ring with gold(I) results in a high-frequency shift of the (31)P signal of the directly coordinated P atom, whereas a low-frequency shift is observed for the P atom at the opposite end of that ring. Based on these results, a previous assignment made for the complex salts [Au(PMe3)4][Au{Co(P2C2Ad2)2}2] and [K(18-crown-6)(thf)2][Au{Co(P2C2Ad2)2}2] (Ad=adamantyl) must be corrected.
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