Metal–carbonyl and metal–nitrosyl complexes. Part I. X-Ray analysis of the tricarbonylchromium derivative of the adduct of diphenylketen and ethoxyacetylene

Abstract

X-Ray analysis of the tricarbonylchromium derivative of the adduct of diphenylketen and ethoxyacetylene has confirmed the structure (I) assigned to the adduct by Barton et al. In the metal complex (II) the conjugated system of the cycloheptatriene ring is approximately planar and displays an alternation in bond lengths. The sp³-carbon atom of the cycloheptatriene ring and the chromium atom are on opposite sides of the six-carbon conjugated system. The average sp²-carbon–chromium distance is 2·23 Å. The tricarbonychromium complex (II) crystallises in the triclinic system, space group P, with four molecules of C₂₁H₁₆CrO₅ in a unit cell of dimensions a= 11·71, b= 12·78, c= 13·47 Å, α= 87°O′, β= 109°45′, γ= 106°26′.