Decamethyl- and octamethyl-ferrocenium salts of F-1- and F-2-TCNQ: Effects of fluorine substitution on the crystal structures and magnetic interactions

摘要

Decamethyl- and octamethyl-ferrocenium salts of F(n)TCNQ (n = 1, 2) were prepared and their crystal structures characterized. The 2,5-F(2)TCNQ salts [Fe(C5Me5)(2)](2,5-F(2)TCNQ) (1) and [Fe(C5Me4H)(2)] (2,5-F(2)TCNQ) (2) exhibit one-dimensional center dot center dot center dot [D](+)[A] [D](+)[A] center dot center dot center dot mixed-stack structures, while the salts with polar acceptors [Fe(C5Me5)(2)][A] (A = F(1)TCNQ (3), 2,3-F(2)TCNQ (4), 2,6-F(2)TCNQ (5)) and [Fe(C5Me4H)(2)] [A] (A = 2,3-F(2)TCNQ (6), 2,6-F(2)TCNQ (7)) consist of [D](+)[A(2)](2) [D](+) units involving a diamagnetic dimer of the acceptors. These salts are isomorphous to the corresponding TCNQ salts. 1 and 2 exhibit small ferromagnetic interactions at low temperatures. 1 undergoes an antiferromagnetic phase transition at T-N = 3.9 K, which is higher than T-N = 2.1 K of the metamagnetic polymorph of [Fe(C5Me5)(2)](TCNQ). (C) 2014 Elsevier B.V. All rights reserved.