Hexakis{μ₂-4-[2-(diisopropylamino)ethylamino]pent-3-en-2-onato-κ³N,O:O}tricalcium(II) hexane solvate

Abstract

Key indicators: single-crystal X-ray study; T = 110 K; mean (C-C) = 0.002 Å; disorder in main residue; R factor = 0.041; wR factor = 0.105; data-to-parameter ratio = 19.5.The title compound, [Ca 3 (C 13 H 25 N 2 O) 6 ]ÁC 6 H 14 , is a trinuclear complex with all Ca atoms presenting octahedral coordination. The central Ca atom (as well as the hexane solvent molecule) is located on a crystallographic twofold rotation axis and is coordinated by six bridging O atoms, with Ca-O distances ranging from 2.344 (1) to 2.351 (1) Å . The terminal Ca atoms are coordinated by three bridging O atoms, with Ca-O distances ranging from 2.311 (1) to 2.335 (1) Å , and three N atoms of the -ketoiminate ligands, with Ca-N distances ranging from 2.432 (1) to 2.452 (1) Å . One of the diisopropylamino groups is disordered over two positions, with site occipancy factors of ca 0.54 and 0.46. Hexakis{ 2 -4-[2-(diisopropylamino)ethylamino]pent-3-en-2-onato-3 N,O:O}tricalcium(II) hexane solvate P. Richard, M. Eleter, L. G. Hubert-Pfalzgraf and S. DanieleCommentThe title compound was obtained by reaction between the Ca silylamide Ca[N(SiMe 3 ) 2 ] 2 (THF) 2 (Westerhausen, 1991) and the ketoimine. Its solid state structure is similar to that of the strontium derivative. However, 1 H NMR data in solution (CDCl 3 or C 6 D 6 ) show the presence of two different molecular species. In concentrated solution (1.4 M in CDCl 3 ), one specie accounts for about 90% of the resonances while the amount of the second specie increases by dilution. These data suggest an equilibrium between a trinuclear form (I) having the solid state structure and a dimeric structure which could be similar to that reported for a tetrakis(β-ketoiminate)di-magnesium (Corazza et al., 1988).