Cyclic trimer of tripodal trisilanol with new hydrogen bonding motif

Abstract Tripodal trisilanols tris[4-(diisopropylhydroxysilyl)phenyl]-phenylsilane and -methylsilane ( 3a and 3b ) as well as 1,3,5-tris(diisopropylhydroxysilylmethyl)-2,4,6-triethylbenzene ( 3c ) were synthesized by treatment of the corresponding tribromide with alkyl lithium or magnesium, followed by silylation with diisopropylchlorosilane, halogenation with trichloroisocyanuric acid (TCCA) or N -bromosuccinimide (NBS), and subsequent alkaline hydrolysis. X-ray analyses of the tripodal silanols ( 3a – c ) revealed the first example of a cyclic trimer in the silanol hydrogen bonding pattern. The connectivity of silanol hydrogen bonding in the silanol products was found to produce a 1D network, based on X-ray packing structures. Substituent effects for this new mode of silanol hydrogen bonding were estimated by hydrogen bonding energy [ E H−bond ] based on DFT calculations. Other new silanol hydrogen bonding features were characterized using Bader's Atom in Molecules (AIM) analyses.