Graziano Brendan J, Scott Thais R, Vollmer Matthew V, Dorantes Michael J, Young Victor G, Bill Eckhard, Gagliardi Laura, Lu Connie C
Department of Chemistry, University of Minnesota-Twin Cities 207 Pleasant Street SE Minneapolis Minnesota 55455 USA
Department of Chemistry, The University of Chicago, Searle Chemistry Laboratory 5735 South Ellis Avenue Chicago Illinois 60637 USA
Chem Sci. 2022 May 5;13(22):6525-6531. doi: 10.1039/d2sc01998a. eCollection 2022 Jun 7.
Odd-electron bonds have unique electronic structures and are often encountered as transiently stable, homonuclear species. In this study, a pair of copper complexes supported by Group 13 metalloligands, M[N((-CH)NCHPPr)] (M = Al or Ga), featuring two-center/one-electron (2c/1e) σ-bonds were synthesized by one-electron reduction of the corresponding Cu(i) ⇢ M(III) counterparts. The copper bimetallic complexes were investigated by X-ray diffraction, cyclic voltammetry, electron paramagnetic spectroscopy, and density functional theory calculations. The combined experimental and theoretical data corroborate that the unpaired spin is delocalized across Cu, M, and ancillary atoms, and the singly occupied molecular orbital (SOMO) corresponds to a σ-(Cu-M) bond involving the Cu 4p and M s/p atomic orbitals. Collectively, the data suggest the covalent nature of these interactions, which represent the first examples of odd-electron σ-bonds for the heavier Group 13 elements Al and Ga.
奇电子键具有独特的电子结构，并且经常作为瞬态稳定的同核物种出现。在本研究中，通过对相应的Cu(i)⇢M(III)配合物进行单电子还原，合成了一对由13族金属配体M[N((-CH)NCHPPr)]（M = Al或Ga）支撑的铜配合物，其具有双中心/单电子(2c/1e)σ键。通过X射线衍射、循环伏安法、电子顺磁共振光谱和密度泛函理论计算对铜双金属配合物进行了研究。实验和理论数据相结合证实，未成对电子自旋在Cu、M和辅助原子之间离域，且单占据分子轨道(SOMO)对应于一个涉及Cu 4p和M s/p原子轨道的σ-(Cu-M)键。总体而言，这些数据表明了这些相互作用的共价性质，这代表了较重的13族元素Al和Ga的奇电子σ键的首个实例。
