Iron(II) Complexes with Boron Cluster Anion [B10Cl10]2-: Intermolecular Interactions according to 35Cl NQR Spectroscopy and X-ray Diffraction

Secondary interactions, in which decachloro-closo-decaborate anions are involved were studied in solvates [Fe(phen)(3)][B10Cl10]0.875CH(3)CN center dot 0.125H(2)O (1), {[Fe(bipy)(3)][B10Cl10]}center dot 2Bipy center dot 0.5CH(3)CN (2), {[Fe(bipy)(3)](2)[B10Cl10](2)}center dot 2.25CH(3)CN (3), and [Fe(bipy)(3)](3)[B10Cl10](3)2CH(3)CN center dot H2O (4). Structures 1-4 were determined by X-ray diffraction analysis, and complexes 1-3 were studied using Cl-35 NQR spectroscopy. A number of C-H center dot center dot center dot Cl and p center dot center dot center dot pi interactions between chlorine atoms and delocalized electron density of phenyl rings or CN groups of acetonitrile molecules were identified. The results obtained by the two methods were compared and the relative strength of secondary interactions were estimated.