Experimental and Computational Insights into Carbon Dioxide Fixation by RZnOH Species

Organozinc hydroxides ,R ZnOH, possessing the proton-reactiv ea lkylzinc group and the CO2-reactive Zn¢OH group, represent an intriguing group of organometallic pre- cursors for the synthesis of novel zinc carbonates .C ompre- hensive experimental and computational investigations on 1) solution an ds olid-stat eb ehavior of tBuZnOH (1 )s pecies in the presence of Lewis bases, namely ,T HF and 4-methyl- pyridine ;2 )s tep-by-step sequence of the reactio nb etween 1 and CO2 ;a nd 3) the effect of ad onor ligand and/or an excess of tBu2Zn as an external proto na cceptor on the reac- tion course are reported. DFT calculations for the insertion of carbon dioxide into the dinuclea ra lkylzinc hydroxide 12 are fully consisten tw ith 1 HN MR spectroscopy studies and indi- cate that this process is am ultistep reaction, in which the in- sertion of CO2 seems to be the rate-determining step. More- over ,D FT studies show that the mechanism of the rearrange- ment between key intermediates, that is, the primary alkyl- zinc bicarbonate with ap roximal position of hydrogen and the secondary alkylzinc bicarbonate with ad istal positio no f hydrogen, most likely proceeds through internal rotatio no f the dinuclear bicarbonate.