Unusual reaction of ( E )-2-[(benzo[ d ]thia-zol-2-yl-imino)-meth-yl]-5-(di-ethyl-amino)-phenol with tri-phenyl-borane: crystal structures and optical properties.

The mol-ecular and crystal structure of ( E )-2-[(benzo[ d ]thia-zol-2-yl-imino)-meth-yl]-5-(di-ethyl-amino)-phenol (C 18 H 19 N 3 O 2 S, Et 2 N-Bz ) and its unexpected reaction product with tri-phenyl-borane, 2,2-diphenyl-1,3-dioxa-2-borata-1,2-di-hydro-naphthalene [systematic name: N , N -diethyl-2,2-diphenyl-2 H -1,3λ 3 ,2λ 4 -ben-zodioxaborinin-7-amine, C 23 H 24 BNO 2 , ( I )] are described. For Et 2 N-Bz , the hydroxyl group is involved in an intra-molecular hydrogen bond with the imino nitro-gen atom and the C=N bond displays an E configuration. The crystal packing is characterized by layers of inversion dimers parallel to the (10) plane and chains of mol-ecule in the a -axis direction formed through C-H⋯O inter-actions. Complex ( I ) crystallizes with two mol-ecules ( A and B ) in the asymmetric unit, which differ in the orientation of the ethyl groups. The 1,3-dioxa-2-borata-1,2,3,4-tetra-hydro-naphthalene ring displays a slight envelope conformation with the boron atom as the flap. In the crystal packing, chains of alternating A and B mol-ecules formed by C-H⋯O hydrogen bonds run in the b -axis direction. The UV-vis absorption and emission properties of the compounds are discussed and their aggregation-induced emission properties are further investigated.