In situ Synthesis, Crystal Structures, and Characterization of Three Milrinone Tetrazolyl Complexes.

Abstract. In situ [2+3] cycloaddition reactions of milrinone [= 3-cyano-6-methyl-5-(4-pyridyl)-2-pyridone] with sodium azide in the presence of MnCl₂ ·4H₂O, FeSO₄ ·7H₂O, or CoCl₂ ·6H₂O as Lewis acids, gave three new complexes {[Mn(Mitz)₂(H₂O)₂] ·(H₂O)} ( 1), {[Fe(Mitz)₂(H₂O)₂] ·(H₂O)} ( 2), and {[Co(Mitz)₂(H₂O)₂] ·(H₂O)} ( 3) [Mitz = 3-tetrazole-6-methyl-5-(4-pyridyl)-2-pyridone]. All the complexes were characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis, X-ray powder diffraction, and thermogravimetric analysis. X-ray diffraction analyses show that complexes 1- 3 have isomorphous structures. The central metal atoms in these complexes are hexacoordinated and connected by two water molecules, two nitrogen atoms from different tetrazolyl groups, and two oxygen atoms from carbonyl functions respectively. The fluorescent emission spectrum of 1 in the solid-state at room temperature shows a maximal emission peak at 365 nm. [ABSTRACT FROM AUTHOR]