Synthesis, Crystal Structure, Fluorescence and Thermostability of Ni(II), Zn(II), Cd(II) Complexes with Schiff Base 2-Acetylpyridine-d-tryptophan

Three novel transition metal coordination polymers, [Ni(C 18 H 16 N 3 O 2 ) 2 ·2CH 3 OH] n ( 1 ), [Zn(C 18 H 16 N 3 O 2 ) 2 ·4CH 3 OH] n ( 2 ) and [Cd(C 18 H 16 N 3 O 2 ) 2 ·2CH 3 OH] n ( 3 ) (C 18 H 16 N 3 O 2 =2-acetylpyridine- d -tryptophan) were synthesized and characterized by elemental analysis, IR, UV, 1 H NMR and X-ray diffraction single crystal analysis. The analyses of the structures indicate that all three materials crystallize in the tetragonal crystal system, space group P 4 1 2 1 2. They have similar structures; i.e., the Schiff base coordinates in its deprotonated form and behaves as a hexadentate (4N+2O) coordinated ligand to form a distorted octahedron geometry. On the other hand, as a result of the alternate arrangement of chains through N–H···O intermolecular hydrogen bonds interactions, 2-D layers are formed for the three complexes. Furthermore, the luminescent properties and thermal stabilities of the three complexes were investigated.