Synthesis and Characterization of New Strontium Complexes with Multidentate Ligands

초록

A series of new strontium complexes, [Sr(tmtad)(btsa)](2) (1), [Sr(ptmtad)(btsa)](2) (2), [Sr(etmtad)(btsa)](2) (3), [Sr(tmtad)(tmhd)](2) (4), [Sr(ptmtad)(tmhd)](2) (5), and [Sr(etmtad)(tmhd)](2) (6), were successfully synthesized by substitution reactions between btsa, aminoalkoxide ligands, and tmhdH (btsa=bis(trimethylsilyl) amide, tmtadH=2,5,9,12-tetramethyl-2,5,9,12-tetraazatridecan-7-ol, ptmtadH=2,5,7,9,12-pentamethyl-2,5,9,12-tetraazatridecan-7-ol, etmtadH=7-ethyl-2,5,9,12-tetramethyl-2,5,9,12-tetraazatridecan-7-ol, tmhdH=2,2,6,6-tetramethyl-3,5-heptanedione). Thermogravimetric analysis (TGA) of the new strontium compounds showed low residual masses (4-11 %) where complex 4 displayed the highest volatility and thermal stability. Single crystal X-ray study of complexes 1, 3, and 6 revealed that the respective complexes crystalize in a triclinic space group as a dimer with a hexa- or hepta-coordination. Furthermore, dimethylamino nitrogen atoms of aminoalkoxide ligands are freely pendent without coordinating to the central strontium metal due to their steric hindrance on the coordination sphere. Compounds 1-6 were characterized by H-1- and C-13-nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, elemental analysis (EA), and thermogravimetric analysis.

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