TY - JOUR
T1 - Transition metal complexes with more than one dihydrogen ligand
T2 - Structure and bonding of M(CO)6-x(H2)x (M = Cr, Mo, W; x = 1, 2, 3)
AU - Dapprich, Stefan
AU - Frenking, Gernot
PY - 1998
Y1 - 1998
N2 - Quantum mechanical ab initio calculations at the MP2 and CCSD(T) level of theory have been used to investigate the geometries and bond energies of the complexes M(CO)6-x(H2)x (M = Cr, Mo, W; x = 1, 2, 3). The theoretically predicted M(CO)5-(H2) bond dissociation energies are in excellent agreement with experimental values. The M-(H2) dissociation energies of the bis- and tris-dihydrogen complexes are very similar to the values for the mono-dihydrogen complexes. In M(CO)5(H2) the dihydrogen ligand prefers an eclipsed conformation relative to the equatorial carbonyl groups. For M(CO)4(H2)2 the cis and trans isomers are nearly equal in energy for M = W, while a cis configuration is favoured for M = Cr. For M(CO)3(H2)3 the facial configurations are more stable than the meridial structures for all three metals M. The charge decomposition analysis (CDA) classifies dihydrogen as a donor ligand with moderate acceptor properties. In trans-M(CO)4(H2)2 back donation is increased and the M-(H2) bonds are stronger than in M(CO)5-(H2). Back donation in M(CO)3(H2)3 is slightly weaker than in the mono-dihydrogen complexes M(CO)5(H2).
AB - Quantum mechanical ab initio calculations at the MP2 and CCSD(T) level of theory have been used to investigate the geometries and bond energies of the complexes M(CO)6-x(H2)x (M = Cr, Mo, W; x = 1, 2, 3). The theoretically predicted M(CO)5-(H2) bond dissociation energies are in excellent agreement with experimental values. The M-(H2) dissociation energies of the bis- and tris-dihydrogen complexes are very similar to the values for the mono-dihydrogen complexes. In M(CO)5(H2) the dihydrogen ligand prefers an eclipsed conformation relative to the equatorial carbonyl groups. For M(CO)4(H2)2 the cis and trans isomers are nearly equal in energy for M = W, while a cis configuration is favoured for M = Cr. For M(CO)3(H2)3 the facial configurations are more stable than the meridial structures for all three metals M. The charge decomposition analysis (CDA) classifies dihydrogen as a donor ligand with moderate acceptor properties. In trans-M(CO)4(H2)2 back donation is increased and the M-(H2) bonds are stronger than in M(CO)5-(H2). Back donation in M(CO)3(H2)3 is slightly weaker than in the mono-dihydrogen complexes M(CO)5(H2).
KW - Chromium
KW - Molybdenum
KW - Transition metal carbonyl dihydrogen complexes
KW - Tungsten
KW - ab inito calculations
UR - http://www.scopus.com/inward/record.url?scp=0032377780&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1521-3749(199804)624:4<583::AID-ZAAC583>3.0.CO;2-P
DO - 10.1002/(SICI)1521-3749(199804)624:4<583::AID-ZAAC583>3.0.CO;2-P
M3 - 文章
AN - SCOPUS:0032377780
SN - 0044-2313
VL - 624
SP - 583
EP - 589
JO - Zeitschrift fur Anorganische und Allgemeine Chemie
JF - Zeitschrift fur Anorganische und Allgemeine Chemie
IS - 4
ER -