One-Dimensional Coordination Polymers with Phenyl-carbaborane Anions: Ag(I)/4,4‘-Bipyridine and 2,3-Bis-(2-pyridyl)pyrazine Complexes

A series of new silver/4,4‘-bipyridine [Ag(I)/bpy] and silver/2,3-bis-(2-pyridyl)pyrazine [Ag(I)/bppz] crystalline
complexes with the C-phenyl-carbaborane anion [PhCB9H9]- and the halogenated C-phenyl-carbaborane (HPC) anions [PhCB9H8Br]-,
[BrC6H4CB11H11]-, [PhCB9H4I5]-, and [PhCB11H5I6]- has been prepared and characterized by elemental analysis, infrared
spectroscopy, and single-crystal X-ray diffraction analysis. While {Ag(bppz)[PhCB9H8Br]} (6) has been isolated as a discrete dimeric
complex, all the remaining complexes feature 1D polymeric coordination chains. Among these 1D coordination chains, only [Ag(bpy)][PhCB9H9](CH3CN) (1) and [Ag2(bppz)3][BrC6H4CB11H11]2(CH3CN) (5) exhibit structures where the carbaborane anions act
as simple counteranions and thus are not involved directly in the coordination network. In all the other species, significant framework-construction interaction of the silver center with the {BH} or {BI} units of the carbaborane anions is observed. Interestingly, in
complex {Ag(bppz)[PhCB9H9]} (CH3CN)0.5 (4) the Ag(I) center has an octahedral geometry with two Ag···H−B interactions between
the silver atom and phenyl-carbaborane anion. The influence of the carbaborane anions on the structural features of coordination
chains is analyzed and discussed, and the preparation of the [NEt4]+ salts of the [PhCB9H8Br]-, [BrC6H4CB11H11]-, and [PhCB9H4I5]-
anions is also presented.