Application of POCOP Pincer Nickel Complexes to the Catalytic Hydroboration of Carbon Dioxide

作者：Zhang, Jie^*; Chang, Jiarui; Liu, Ting; Cao, Bula; Ding, Yazhou; Chen, Xuenian^*

来源：Catalysts, 2018, 8(11): 508.

DOI：10.3390/catal8110508

• nickel catalyst
• hydroboration
• carbon dioxide
• catecholborane
• pincer complex
• mercapto complex
• azido complex
• isothiocyanato complex

The reduction of CO2 is of great importance. In this paper, different types of bis(phosphinite) (POCOP) pincer nickel complexes, [2,6-(R2PO)(2)C6H3]NiX (R = Bu-t, Pr-i, Ph; X = SH, N-3, NCS), were applied to the catalytic hydroboration of CO2 with catecholborane (HBcat). It was found that pincer complexes with (Bu2P)-Bu-t or (Pr2P)-Pr-i phosphine arms are active catalysts for this reaction in which CO2 was successfully reduced to a methanol derivative (CH(3)OBcat) with a maximum turnover frequency of 1908 h(-1) at room temperature under an atmospheric pressure of CO2. However, complexes with phenyl-substituted phosphine arms failed to catalyze this reaction-the catalysts decomposed under the catalytic conditions. Complexes with (Pr2P)-Pr-i phosphine arms are more active catalysts compared with the corresponding complexes with (Bu2P)-Bu-t phosphine arms. For complexes with the same phosphine arms, the catalytic activity follows the series of mercapto complex (X = SH) approximate to azido complex (X = N-3) >> isothiocyanato complex (X = NCS). It is believed that all of these catalytic active complexes are catalyst precursors which generate the nickel hydride complex [2,6-(R2PO)(2)C6H3]NiH in situ, and the nickel hydride complex is the active species to catalyze this reaction.

• 出版日期2018-11
• 单位河南师范大学