TY - JOUR
T1 - Complex Chemistry of Reactive Organic Compounds. 46.†1Conformation of Metal Carbene Complexes
T2 - Synthesis and Structure of (η5-C5H5)Cr(CO)(NO)[C(C6H5)2and Its Relationship to the Isoelectronic Compound (η5-C5H5)Mn(CO)2[C(C6H5)2]
AU - Herrmann, Wolfgang A.
AU - Hubbard, John L.
AU - Bernal, Ivan
AU - Korp, Jim D.
AU - Haymore, Barry L.
AU - Hillhouse, Gregory L.
PY - 1984/12
Y1 - 1984/12
N2 - Reaction of CpCr(CO)(NO)(thf) (Cp = η5-C5H5, thf = tetrahydrofuran) with diphenyldiazomethane gives the new carbene complex CpCr(CO)(NO)[C(C6H5)2] (2). The complex crystallizes in the monoclinic space group P21/n (a = 11.090 (2) Å, b = 10.579 (3) Å, c = 13.804 (3) Å, β = 92.43 (2)°). The structure shows the carbene plane to be nearly coplanar with the plane described by the N-Cr-C(carbene) fragment and nearly perpendicular to the C(carbonyl)-Cr-C(carbene) plane. In this orientation, the carbene ligand chooses to align itself with the most basic of the two potential π-donor orbitals of the CpCr(CO)(NO) fragment, e.g., the one not stabilized by the nitrosyl ligand. The resulting Cr-C(carbene) bond length of 1.912 Å is the shortest Cr-carbene distance yet reported. The structure of the isoelectronic compound CpMn(CO)2[C(C6H5)2] (4) is reported for comparison. The manganese complex crystallizes in the space group P21/c (a = 12.882 (2) Å, b = 7.380 (2) Å, c = 17.243 (2) Å, β = 106.95 (1)°). This latter structure sharply contrasts with that of the chromium derivative 2 in that the carbene plane is coincident with the mirror plane of the CpMn(CO)2fragment. Analysis of the room-temperature 1H and 13C NMR spectra of the two complexes shows the chromium-carbene conformation is locked whereas manganese-carbene rotation is fast.
AB - Reaction of CpCr(CO)(NO)(thf) (Cp = η5-C5H5, thf = tetrahydrofuran) with diphenyldiazomethane gives the new carbene complex CpCr(CO)(NO)[C(C6H5)2] (2). The complex crystallizes in the monoclinic space group P21/n (a = 11.090 (2) Å, b = 10.579 (3) Å, c = 13.804 (3) Å, β = 92.43 (2)°). The structure shows the carbene plane to be nearly coplanar with the plane described by the N-Cr-C(carbene) fragment and nearly perpendicular to the C(carbonyl)-Cr-C(carbene) plane. In this orientation, the carbene ligand chooses to align itself with the most basic of the two potential π-donor orbitals of the CpCr(CO)(NO) fragment, e.g., the one not stabilized by the nitrosyl ligand. The resulting Cr-C(carbene) bond length of 1.912 Å is the shortest Cr-carbene distance yet reported. The structure of the isoelectronic compound CpMn(CO)2[C(C6H5)2] (4) is reported for comparison. The manganese complex crystallizes in the space group P21/c (a = 12.882 (2) Å, b = 7.380 (2) Å, c = 17.243 (2) Å, β = 106.95 (1)°). This latter structure sharply contrasts with that of the chromium derivative 2 in that the carbene plane is coincident with the mirror plane of the CpMn(CO)2fragment. Analysis of the room-temperature 1H and 13C NMR spectra of the two complexes shows the chromium-carbene conformation is locked whereas manganese-carbene rotation is fast.
UR - http://www.scopus.com/inward/record.url?scp=0010844061&partnerID=8YFLogxK
U2 - 10.1021/ic00187a016
DO - 10.1021/ic00187a016
M3 - Article
AN - SCOPUS:0010844061
SN - 0020-1669
VL - 23
SP - 2978
EP - 2983
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 19
ER -