SYNTHESIS OF trans-(DICHLOROMETHYL)BIS(2,4-PENTANEDIONATO)(AQUA, PYRIDINE, OR METHANOL)CHROMIUM(III) AND CRYSTAL STRUCTURE OF trans-(DICHLOROMETHYL)BIS(2,4-PENTANEDIONATO)PYRIDINECHROMIUM(III)

Abstract

The complexes, [Cr(CHCl2)(acac)2L] (L = H2O, CH3OH, and pyridine), were prepared, where acac− denotes 2,4-pentanedionate ion. [Cr(CHCl2)(acac)2(CH3OH)] reacts with pyridine(py) rapidly to give [Cr(CHCl2)(acac)2(py)]. The structure of [Cr(CHCl2)-(acac)2(py)] has been determined to be trans by single crystal X-ray diffraction. The Cr–N(py) bond lengthens to 2.16(1) Å. This may be associated with that rapid substitution reaction.

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“…The difference in bond lengths in 5b is much more defined, where Cr1 is the likely trivalent species with overall shorter bond lengths. The Cr2−C1 bond lengths in 5a (2.05(1) Å) and 5b (2.046(2) Å) are similar to the bridging methylidene in 3, but are shorter than those in [Cr(acac) 2 (CHCl 2 )(py)] (2.13(1)/2.129(8) Å), 32,33 representing the only other dihalido-methanide chromium complex structurally characterized. In fact, [Ti(Cp)(acac)(μ 3 -S) 2 Ir 2 I-(CHI 2 )(CO) 4 ] seems to be the only other complex containing a di-iodo-methanide ligand.…”