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Free keywords:
carbonyl ligands; cobalt; density functional calculations; nitrosyl ligands; vibrational spectroscopy
Abstract:
The reaction of [Co2(CO)8] with (CF3)3BCO in hexane leads to the Lewis acid–base adduct [Co2(CO)7CO-B(CF3)3] in high yield. When the reaction is performed in anhydrous HF solution [Co(CO)5][(CF3)3BF] is isolated. The product contains the first example of a homoleptic metal pentacarbonyl cation with 18 valence electrons and a trigonal‐bipyramidal structure. Treatment of [Co2(CO)8] or [Co(CO)3NO] with NO+ salts of weakly coordinating anions results in mixed crystals containing the [Co(CO)5]+/[Co(CO)2(NO)2]+ ions or pure novel [Co(CO)2(NO)2]+ salts, respectively. This is a promising route to other new metal carbonyl nitrosyl cations or even homoleptic metal nitrosyl cations. All compounds were characterized by vibrational spectroscopy and by single‐crystal X‐ray diffraction.
