Redox Ladder of Ni<sub>3</sub> Complexes with Closed‐Shell, Mono‐, and Diradical Triphenylene Units: Molecular Models for Conductive 2D MOFs
Luming Yang, Mircea Dincă
Abstract
Abstract We report the isolation and characterization of a series of trinickel complexes with 2,3,6,7,10,11‐hexaoxytriphenylene (HOTP), [(Me 3 TPANi) 3 (HOTP)](BF 4 ) n (Me 3 TPA= N , N , N ‐tris[(6‐methyl‐2‐pyridyl)methyl]amine) ( n =2, 3, 4 for complexes 1 , 2 , 3 ). These complexes comprise a redox ladder whereby the HOTP core displays increasingly quinoidal character as its formal oxidation state changes from −4, to −3, and −2 in 1 , 2 , and 3 , respectively. No formal oxidation state changes occur on Ni, allowing the isolation of singlet diradical, monoradical, and closed‐shell configurations for HOTP in 1 , 2 , and 3 , respectively, with a concomitant decrease in the spin coupling strength upon oxidation. Because the three complexes can be considered models of the smallest building blocks of 2D conductive metal‐organic frameworks such as Ni 9 HOTP 4 , these results serve as possible inspiration for the construction of extended materials with targeted electric and magnetic properties.