| Abstract
| - Two experimental techniques were used to elucidate howacetonitrile molecules are bound to the title complex,[Cr(acac)3]: (i) measurement of NMR longitudinalrelaxation rates of the dipolar nuclei of the solvent(1H,methyl-13C, and cyano-13C ofCH3CN) in the presence of[Cr(acac)3], which is a paramagnetic complex,and(ii) X-ray diffraction measurements on acetonitrile solutions of[Cr(acac)3] and [Ru(acac)3] usingan isostructuralsubstitution method. The results of both methods are in harmonywith each other. Four acetonitrile moleculesare found within about 6 × 10-10 m from thechromium atom. They are in the hollows on theperipheralsurface of the three acetylacetonato ligands, one or two in the hollowsalong the C3 axis of the complex,andtwo or three in the hollows along the C2 axes.They are oriented with the methyl ends inward: theanglebetween the molecular axis of acetonitrile and the vector from thechromium atom to the methyl carbon ofacetonitrile was about 100°.
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