title: Polytypic phase transition in alkyl chain-functionalized valence tautomeric complexes.
abstract: A novel series of valence tautomeric (VT) complexes, [Co(Cnbpy)(3,5-DTBQ)2] (Cnbpy = 4,4'-dialkyl-2,2'-bipyridine (alkyl = (C(n)H(2n+1)) where n = 0 (CoC0bpy), 1 (CoC1bpy), 5 (CoC5bpy), 9 (CoC9bpy) and 13 (CoC13bpy); 3,5-DTBQ = 3,5-di-tert-butylsemiquinonate or catecholate), including two previously reported complexes (CoC0bpy and CoC1bpy), were systematically prepared and their properties examined. Introduction of alkyl groups into VT chromophores leads to unexpected variations in the VT process, depending on the lengths of the alkyl chains. An even more interesting observation is that significant polytypic phase transitions with crystallographic symmetry changes accompanying the abrupt VT conversion are induced for the first time in CoC9bpy and CoC13bpy.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kiriya
authors.forename: Ho-Chol
authors.initials: HC
authors.lastname: Chang
authors.forename: Akiko
authors.initials: A
authors.lastname: Kamata
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa