Rhenium hydrido complex anion

The chemistry of the metal carbonyl hydrides and metal carbonylates remained the principal research topic for Hieber until the 1960s. He mentioned in his account [25], that it was a particular pleasure for him that in his laboratory the first hydrido carbonyl complexes of the manganese group, HMn(CO)5 and HRe(CO)5, were prepared by careful addition of concentrated phosphoric acid to solid samples of the sodium salts of the [M(CO)5] anions, giving the highly volatile hydrido derivatives in nearly quantitative yield [45, 46]. In contrast to HCo(CO)4 and its rhodium and iridium analogues, the pentacarbonyl hydrido compounds of manganese and rhenium are thermally remarkably stable, and in... 

Kinetic studies on the photogeneration of CO using [Re(bpy)(CO)3Cl] in a DMF/TEOA solution shows a linear relationship between formation of CO and time when excess chloride anions are present [19]. A 14 % quantum yield has been determined. The absence of excess Cl lowers the CO generation (8.7 % quantum yield), due to the formation in solution of a formato-rhenium (I) species as observed by NMR, FT-IR spectroscopies and also confirmed by X-ray crystal stracture determination [70]. This new complex could be formed by insertion of CO2 into a hydrido-rhenium (I) species (eq. 11) [71], formed as a by-product during the process. 

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