Synthesis and structure of novel strontium complexes of unsymmetrically functionalized beta-diketimine ligands

Abstract

A series of tridentate beta-diketiminate ligands, (2Z, 4E)-4-{[2-(dimethylamino) ethyl] imino}-N-(propan-2-yl) pent-2-en-2-amine ((LH)-H-1), (2Z, 4E)-4-{[3-(dimethylamino) propyl] imino}-N-(tert-butyl) pent-2-en-2-amine ((LH)-H-2), and (2Z, 4E)-4-{[3-(dimethyl-amino) propyl] imino}-N-(propan-2-yl) pent-2-en-2-amine ((LH)-H-3), and their strontium complexes, SrL21 (1), SrL22 (2), and SrL23 (3) were synthesized as potential strontium precursors, by the reaction of Sr[N(SiMe3)(2)](2) and two equivalents of (LH)-H-1, (LH)-H-2, and (LH)-H-3, respectively. Compounds 1-3 were characterized by spectroscopic (IR, MS, H-1 and C-13 NMR), microanalytical methods, and single crystal X-ray diffractometry. The X-ray crystal structure reveals that complex 1 has a monoclinic space group, C2/c. The structure shows the bonding of two beta-diketiminate ligands to the strontium metal through six nitrogen atoms. Additionally, the isopropyl groups on the ligands force 1 to attain a highly distorted octahedron. Thermogravimetric analyses of the compounds 1-3 exhibit a primary mass loss on 130-300 degrees C region. (C) 2011 Elsevier B. V. All rights reserved.