The Ground Spin States of Tris[p-(N-oxyl-N-tert-butylamino)phenyl]amine,-Methyl,and -Borane.Prospects of Further Studies

摘要

An exploratory study has been carried out on new poly(aminoxyl) radicals as potential bridging ligands for 2p/3d-hybrid-spin metal complexes having network structures. Temperature dependence of the magnetic susceptibility data on the title amine N in the range 2-300 K was analyzed to show that its ground state was a doublet with a quartet state lying 559 K ( = 1.11 kcal mol~(-1)) above the doublet. B3L YP/6-31G~*//B3LYP/6-31G computations on a simplified model molecule (N') confirmed the doublet ground state by 0.84 kcal mol~(-1). The methyl compound (C) is a triplet diradical with a singlet state lying 400 K above the triplet. The hexamethyl derivative (B') of the title borane B has a doublet ground state with an energy gap to a quartet state by 9.9 K. The electronic structures are described qualitatively by p-(N-oxyl-tert-butylamino)phenyl homologues of (·H_2O)_3 X in which X = N,C·, and B atoms, and carries two, one and no #pi#-electrons, respectively. N and B' showed two reversible redox waves. Mn~(II)(hfac)_2 and C gave a black-violet crystalline complex in which the 3d and 2p spins ordered at 60 K.