Knowledge Bank

The transition metal complex $C5H5Cr(CO)2NO$ is a relatively simple, "piano-stool" type complex which provides the opportunity to compare nitrosyl and carbonyl ligand binding. The nitrosyl and carbonyl ligands form significantly different angles with the $C5H5-Cr$ axis, and this results in a near-symmetric-top inertia tensor for the common isotopomer. For the normal isotopomer, A = 1001.693(2), B = 797.2724(6) and C = 797.0143(6) MHz. The $C5H5-Cr-NO$ angle is $126.9(5)\circ$ and the $C5H5-Cr-CO$ angle is $120.1(2)\circ$. The distance from the Cr atom to the $C5H5$ ring is $z(Cr-C5H5)=1.88(1)\backslash AA$. Other structural parameters are obtained and discussed. The $C5H5$ ring is oriented so that two of the cyclopentadienyl carbon atoms are staggered with respect to the NO nitrogen atom. The $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}N$ quadrupole coupling values are $eQqaa=0.312(2)$ and $eQqbb=-0.448(2)$ MHz.