TY - JOUR
T1 - Structure and bonding of the remarkable donor-acceptor complexes xbeo (X=nh3, nme3, co, n2, c2h2, c2h4, h2, h2co, o2)
AU - Frenking, Gernot
AU - Dapprich, Stefan
AU - Köhler, Klaus F.
AU - Koch, Wolfram
AU - Collins, Jackr
PY - 1996
Y1 - 1996
N2 - Quantum mechanical calculations at the MP4/ 6-311G(2df,2pd)(/MP2/ 6- 31G(d, p) level of theory are reported for the compounds XBeO with X=NH3, NMe3, CO, N2, C2 H2, C2 H %, H4, H2 CO and O2 . The calculations show that BeO is a very strong Lewis acid. The X-BeO bond strength is between Dc=69.5 kcal mol-1 " for Me3 NBeO and De=11.2 kcal mol-1" for p -bonded N2 BeO. The calculated bond strength for the yet unknown donor-acceptor complex Me3 NBeO is significantly higher than the strongest experimentally known main-group donor-acceptor complex Me3NAlCl3 (Do=47.5 kcal mol-1"). Even the weak donor H2 is bonded with De=18.5 kcal mol-1. The compounds O2 BeO and its isomer berylliumozonide BeO3 should not be considered as donor-acceptor complexes. The results of the CDA method show that the donor-acceptor interactions in terms of orbital mixing are mainly described by the mixing of occupied orbitals of X with vacant orbitals of BeO, while the mixing of occupied orbitals of BeO with vacant orbitals of X is negligible. The topological analysis of the electronic charge distribution and the NBO partitioning scheme demonstrate that the X-BeO bonds have little or no covalent character; the bonds are caused by electrostatic attraction. The charge concentration at the donor atoms in the stronger bonded compounds is significantly deformed towards the beryllium atom.
AB - Quantum mechanical calculations at the MP4/ 6-311G(2df,2pd)(/MP2/ 6- 31G(d, p) level of theory are reported for the compounds XBeO with X=NH3, NMe3, CO, N2, C2 H2, C2 H %, H4, H2 CO and O2 . The calculations show that BeO is a very strong Lewis acid. The X-BeO bond strength is between Dc=69.5 kcal mol-1 " for Me3 NBeO and De=11.2 kcal mol-1" for p -bonded N2 BeO. The calculated bond strength for the yet unknown donor-acceptor complex Me3 NBeO is significantly higher than the strongest experimentally known main-group donor-acceptor complex Me3NAlCl3 (Do=47.5 kcal mol-1"). Even the weak donor H2 is bonded with De=18.5 kcal mol-1. The compounds O2 BeO and its isomer berylliumozonide BeO3 should not be considered as donor-acceptor complexes. The results of the CDA method show that the donor-acceptor interactions in terms of orbital mixing are mainly described by the mixing of occupied orbitals of X with vacant orbitals of BeO, while the mixing of occupied orbitals of BeO with vacant orbitals of X is negligible. The topological analysis of the electronic charge distribution and the NBO partitioning scheme demonstrate that the X-BeO bonds have little or no covalent character; the bonds are caused by electrostatic attraction. The charge concentration at the donor atoms in the stronger bonded compounds is significantly deformed towards the beryllium atom.
UR - http://www.scopus.com/inward/record.url?scp=0000424860&partnerID=8YFLogxK
U2 - 10.1080/002689796173156
DO - 10.1080/002689796173156
M3 - 文章
AN - SCOPUS:0000424860
SN - 0026-8976
VL - 89
SP - 1245
EP - 1263
JO - Molecular Physics
JF - Molecular Physics
IS - 5
ER -