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Distinct Stepwise Reduction of a NickelNickel‐Bonded Compound Containing an α‐Diimine Ligand: From Perpendicular to Coaxial Structures
Author(s) -
Dong Qingsong,
Yang XiaoJuan,
Gong Shida,
Luo Qiong,
Li QianShu,
Su JiHu,
Zhao Yanxia,
Wu Biao
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302463
Subject(s) - nickel , diimine , ligand (biochemistry) , metal , crystallography , bond length , chemistry , perpendicular , materials science , crystal structure , organic chemistry , catalysis , geometry , biochemistry , receptor , mathematics
A nickelnickel‐bonded complex, [{Ni(μ‐L .− )} 2 ] ( 1 ; L=[(2,6‐ i Pr 2 C 6 H 3 )NC(Me)] 2 ), was synthesized from reduction of the LNiBr 2 precursor by sodium metal. Further controllable reduction of 1 with 1.0, 2.0 and 3.0 equiv of Na, respectively, afforded the singly, doubly, and triply reduced compounds [Na(DME) 3 ] ⋅ [{Ni(μ‐L .− )} 2 ] ( 2 ; DME=1,2‐dimethoxyethane), [Na(Et 2 O)]Na[(L .− )NiNiL 2− ] ( 3 ), and [Na(Et 2 O)] 2 Na[L 2− NiNiL 2− ] ( 4 ). Here L represents the neutral ligand, L .− denotes its radical monoanion, and L 2− is the dianion. All of the four compounds feature a short NiNi bond from 2.2957(6) to 2.4649(8) Å. Interestingly, they display two different structures: the perpendicular ( 1 and 2 ) and the coaxial ( 3 and 4 ) structure, in which the metalmetal bond axis is perpendicular to or collinear with the axes of the α‐diimine ligands, respectively. The electronic structures, NiNi bonding nature, and energetic comparisons of the two structure types were investigated by DFT computations.