Complexes of 2,2′,2″-Nitrilotriphenol. Part 2. Crystal and Molecular Structures of Three Boron Complexes

Crystal and molecular structures of a complex between B ( III ) and the tripod ligand 2,2′,2″-nitrilotriphenol as well as of its pyridine and quinuclidine adducts are presented. The 2,2′,2″-nitrilotriphenyl borate ( III ) molecule shows a strained, tricyclic chelate system with a central N–B donor-acceptor bond of 1.681(5) Å. In the adducts with pyridine ( IV ) and quinuclidine ( III -quin), this bond is broken, the N-atom inverts and is pushed out of the coordination sphere ( B–N _intern = 2.82 Å for Py and 2.85 Å for quin), and a new bond is formed between the boron atom and the external nucleophile ( B–N _extern = 1.631 Å for Py and 1.643 Å for quin).