TY - JOUR
T1 - Binuclear chromium carbonyl complexes of methylaminobis(difluorophosphine)
T2 - metal-metal bonds versus four-electron donor bridging carbonyl groups
AU - Miao, Huijuan
AU - Zhang, Xiuhui
AU - Bai, Yang
AU - Li, Qian shu
AU - King, R. Bruce
N1 - Publisher Copyright:
© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
PY - 2017
Y1 - 2017
N2 - Binuclear chromium carbonyl complexes of the general type [MeN(PF2)2]mCr2(CO)n, including the experimentally known [MeN(PF2)2]3Cr2(CO)n (n = 6, 5) species, have been studied by density functional theory (DFT) methods. The lowest energy structures for the three series of [MeN(PF2)2]mCr2(CO)n (m = 1, 2, 3) structures can be grouped into three triads, namely [MeN(PF2)2]Cr2(CO)n (n = 10, 9, 8), [MeN(PF2)2]2Cr2(CO)n (n = 8, 7, 6), and [MeN(PF2)2]3Cr2(CO)n (n = 6, 5, 4). The carbonyl richest structures of each triad, namely [MeN(PF2)2]Cr2(CO)10, [MeN(PF2)2]2Cr2(CO)8, and [MeN(PF2)2]3Cr2(CO)6 have all terminal carbonyl groups, no chromium-chromium bond, and the MeN(PF2)2 ligands bridging the pair of chromium atoms. However, for [MeN(PF2)2]3Cr2(CO)6 a structure with two of the three MeN(PF2)2 ligands chelating to single chromium atoms are energetically competitive. Low-energy singlet spin state structures for the intermediate and carbonyl poorest members of each triad can incorporate a variety of features such as chromium-chromium single and double bonds, MeN(PF2)2 ligands split into bridging MeNPF2 + PF2 groups, and four-electron donor bridging η2-μ-CO groups as required to give each chromium atom the favored 18-electron configuration. Such four-electron donor bridging η2-μ-CO groups are not found in low-energy structures of related binuclear carbonyl complexes [MeN(PF2)2]mM2(CO)n (M = Fe, Ni; m = 1, 2) of the later transition metals iron and nickel.
AB - Binuclear chromium carbonyl complexes of the general type [MeN(PF2)2]mCr2(CO)n, including the experimentally known [MeN(PF2)2]3Cr2(CO)n (n = 6, 5) species, have been studied by density functional theory (DFT) methods. The lowest energy structures for the three series of [MeN(PF2)2]mCr2(CO)n (m = 1, 2, 3) structures can be grouped into three triads, namely [MeN(PF2)2]Cr2(CO)n (n = 10, 9, 8), [MeN(PF2)2]2Cr2(CO)n (n = 8, 7, 6), and [MeN(PF2)2]3Cr2(CO)n (n = 6, 5, 4). The carbonyl richest structures of each triad, namely [MeN(PF2)2]Cr2(CO)10, [MeN(PF2)2]2Cr2(CO)8, and [MeN(PF2)2]3Cr2(CO)6 have all terminal carbonyl groups, no chromium-chromium bond, and the MeN(PF2)2 ligands bridging the pair of chromium atoms. However, for [MeN(PF2)2]3Cr2(CO)6 a structure with two of the three MeN(PF2)2 ligands chelating to single chromium atoms are energetically competitive. Low-energy singlet spin state structures for the intermediate and carbonyl poorest members of each triad can incorporate a variety of features such as chromium-chromium single and double bonds, MeN(PF2)2 ligands split into bridging MeNPF2 + PF2 groups, and four-electron donor bridging η2-μ-CO groups as required to give each chromium atom the favored 18-electron configuration. Such four-electron donor bridging η2-μ-CO groups are not found in low-energy structures of related binuclear carbonyl complexes [MeN(PF2)2]mM2(CO)n (M = Fe, Ni; m = 1, 2) of the later transition metals iron and nickel.
UR - http://www.scopus.com/inward/record.url?scp=85016251774&partnerID=8YFLogxK
U2 - 10.1039/c7nj00295e
DO - 10.1039/c7nj00295e
M3 - Article
AN - SCOPUS:85016251774
SN - 1144-0546
VL - 41
SP - 2625
EP - 2635
JO - New Journal of Chemistry
JF - New Journal of Chemistry
IS - 7
ER -