Synthesis and Crystal Structures of New Strontium Complexes with Aminoalkoxy and beta-Diketonato Ligands

Abstract

New heteroleptic strontium complexes were synthesized using substitution reaction of bis(trimethylsilyl)amide of Sr(btsa)(2)center dot 2DME with aminoalkoxide and beta-diketonate ligands. The complexes [Sr(bdmp)(btsa)](2)center dot 2THF (1), [Sr(bdeamp)(btsa)](2) (2), [Sr(dadamb)(btsa)](2) (3), [Sr(bdmp)(hfac)](3) (4), [Sr(bdeamp)(hfac)](3) (5), [Sr(dadamb)(hfac)](3) (6), and [Sr-3(dadamb)(4)(tmhd)(2)] (7) were prepared and characterized by means of various analysis techniques such as Fourier transform infrared, NMR, thermogravimetric analysis, and elemental analysis. Complexes 1-3 were further structurally confirmed by single-crystal X-ray crystallography, and they displayed dimeric structures in which strontium atoms were connected by alkoxide oxygen atoms of the mu(2) type. Compound 1 has a trigonal prismatic structure, whereas 2 and 3 have a distorted square pyramidal structure. In complexes 5-7, trimeric structures were obtained with strontium atoms connected by mu(3)-O bonds of alkoxide oxygen atoms and mu(2)-O bonds of alkoxide and beta-diketonate oxygen atoms. The crystal structures of 5, 6, and 7 showed distorted capped octahedral geometry, while 7 (middle Sr atom) displayed a distorted trigonal prism geometry. Complexes 5-7 displayed similar to 70% mass loss in the temperature range from 25 to 315 degrees C.