Molecular and crystal structure of the adduct of cyclohexylisonitrile and praseodymium tricyclopentadienide

Abstract

The crystal structure of (C 5H 5) 3Pr·CNC 6H 11 was determined from single-crystal X-ray diffraction data. The monoclinic unit cell of dimensions a = 8.298(3), b = 21.66(1), c = 11.943(4) Å, and β = 104.98(3)° contains four molecules in general positions of space group P2 1/ c. Each molecule is composed of three C 5H 5 rings in a nearly exact trigonal array, η 5-bonded to the Pr atom at a distance of 2.53 Å to the centroid of each ring, plus a single CNC 6H 11 adduct attached to the Pr atom along the trigonal axis at 2.65 Å. The presence of a CN triple bond in the isonitrile moiety and the nearly linear CNC configuration add credence to the previous proposal that there is a pure donor bond from the isonitrile carbon to the metal atom.