Platinum‐phosphine cluster chemistry: New potentials from ¹⁹⁵Pt‐³¹P{¹H} triple‐resonance spectroscopy

Abstract

Platinum-phosphorus heteronuclear multiple-quaatum coherence spectroscopy has been employed for the characterization of platinum-phosphine cluster compounds. Rules are developed for the interpretation of these spectra, whose appearance depends on the chosen pulse-sequence, phase-cycling and whether direct or remote platinum-phosphorus coupling coostants have been selected. Spectral editing according to the different isotopomers (with respect to ISsPt) is possible when complete evolution of multiple-quantum coherence is allowed. This method offers a substantial advantage in the characterization of larger cluster compounds.

Reaction of triangulo-clusters [Pt3(μ-CO)3(PR3)3] with hexafluorobutyne. The X-ray crystal structures of [Pt2(CO)2(PR3)2(μ-η2:η2-CF3CCCF3)] (PR3= PPh3or PCy3) and [Pt2(CO)2(PBzPh2)(μ-η1:η1-CF3CCCF3)2]

“…The compounds [Pt 3 (CO) 3 (PR 3 ) 3 ], where L = PPh 3 , 8 PBzPh 2 , 8,19 PCy 3 , 20 and P i Pr 3 20 were prepared by literature methods. The 13 C isotopically labeled derivatives were prepared similarly, using 13 CO enriched to 99%. Hexafluoro-2-butyne (Aldrich) and carbon monoxide (> 99% 13 CO) were used as received.…”

Observation of triple-quantum effects in the HMQC spectra of substituted derivatives of Rh6(CO)16 †

“…Ruegger and Moskau have recently presented a set of rules for the interpretation of 31 P detected 195 Pt-31 P HMQC spectra (acquired without phase cycling to allow observation of resonances from multiple-quantum coherences normally suppressed by the phase cycling) of some platinum-phosphine systems in which the detector phosphorus nucleus can couple to two 195 Pt. 6 We now report that where the detector nucleus can couple to three metal spins, e.g. when a face-bridging carbonyl is used to detect 103 Rh in rhodium carbonyl cluster compounds, not only are the correlations displaced from the "true" chemical shift in the rhodium dimension but also may be missing altogether as a result of modulation of the spectral intensity by the multiple metal-quantum transitions.…”

Application of HMQC spectroscopy to the observation of the metal resonance in polymetallic compounds: the effect of multiple‐metal spin transitions

“…One approach is to modify the phase cycling such that all coherences will appear; Ruegger and Moskau 11 have developed a set of rules to identify those correlations corresponding to single-metal spin flips in such spectra of some dimeric platinum-phosphine systems.…”