Sokołowski Kamil, Bury Wojciech, Tulewicz Adam, Cieślak Anna M, Justyniak Iwona, Kubicki Dominik, Krajewska Elżbieta, Milet Anne, Moszyński Robert, Lewiński Janusz
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland).
Chemistry. 2015 Mar 27;21(14):5496-503. doi: 10.1002/chem.201406271. Epub 2015 Feb 18.
Organozinc hydroxides, RZnOH, possessing the proton-reactive alkylzinc group and the CO2 -reactive Zn-OH group, represent an intriguing group of organometallic precursors for the synthesis of novel zinc carbonates. Comprehensive experimental and computational investigations on 1) solution and solid-state behavior of tBuZnOH (1) species in the presence of Lewis bases, namely, THF and 4-methylpyridine; 2) step-by-step sequence of the reaction between 1 and CO2; and 3) the effect of a donor ligand and/or an excess of tBu2Zn as an external proton acceptor on the reaction course are reported. DFT calculations for the insertion of carbon dioxide into the dinuclear alkylzinc hydroxide 12 are fully consistent with (1)H NMR spectroscopy studies and indicate that this process is a multistep reaction, in which the insertion of CO2 seems to be the rate-determining step. Moreover, DFT studies show that the mechanism of the rearrangement between key intermediates, that is, the primary alkylzinc bicarbonate with a proximal position of hydrogen and the secondary alkylzinc bicarbonate with a distal position of hydrogen, most likely proceeds through internal rotation of the dinuclear bicarbonate.
有机氢氧化锌（RZnOH）含有质子反应性的烷基锌基团和二氧化碳反应性的Zn-OH基团，是一类用于合成新型碳酸锌的有趣的有机金属前体。本文报道了关于以下方面的全面实验和计算研究：1）在路易斯碱（即四氢呋喃和4-甲基吡啶）存在下，叔丁基氢氧化锌（1）物种在溶液和固态中的行为；2）1与二氧化碳反应的逐步过程；3）供体配体和/或过量的二叔丁基锌作为外部质子受体对反应过程的影响。对二氧化碳插入双核烷基氢氧化锌12的密度泛函理论计算与核磁共振氢谱研究完全一致，表明该过程是一个多步反应，其中二氧化碳的插入似乎是速率决定步骤。此外，密度泛函理论研究表明，关键中间体之间的重排机制，即氢处于近端位置的伯烷基碳酸氢锌和氢处于远端位置的仲烷基碳酸氢锌之间的重排，很可能是通过双核碳酸氢盐的内旋转进行的。
