Binuclear chromium carbonyl complexes of methylaminobis(difluorophosphine): metal-metal bonds versus four-electron donor bridging carbonyl groups

Huijuan Miao; Xiuhui Zhang; Yang Bai; Qian shu Li; R. Bruce King

doi:10.1039/c7nj00295e

Binuclear chromium carbonyl complexes of methylaminobis(difluorophosphine): metal-metal bonds versus four-electron donor bridging carbonyl groups

Huijuan Miao
, Xiuhui Zhang^*
, Yang Bai
, Qian shu Li
, R. Bruce King

^*Corresponding author for this work

School of Chemistry and Chemical Engineering

Beijing Institute of Technology
South China Normal University
University of Georgia

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	2625-2635
Number of pages	11
Journal	New Journal of Chemistry
Volume	41
Issue number	7
DOIs	https://doi.org/10.1039/c7nj00295e
Publication status	Published - 2017

Access to Document

10.1039/c7nj00295e

Cite this

@article{abd48c8bf1014c26b58588830d77c903,

title = "Binuclear chromium carbonyl complexes of methylaminobis(difluorophosphine): metal-metal bonds versus four-electron donor bridging carbonyl groups",

abstract = "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.",

author = "Huijuan Miao and Xiuhui Zhang and Yang Bai and Li, \{Qian shu\} and King, \{R. Bruce\}",

note = "Publisher Copyright: {\textcopyright} The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.",

year = "2017",

doi = "10.1039/c7nj00295e",

language = "English",

volume = "41",

pages = "2625--2635",

journal = "New Journal of Chemistry",

issn = "1144-0546",

publisher = "Royal Society of Chemistry",

number = "7",

}

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

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 - https://www.scopus.com/pages/publications/85016251774

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 -

Binuclear chromium carbonyl complexes of methylaminobis(difluorophosphine): metal-metal bonds versus four-electron donor bridging carbonyl groups

Abstract

Access to Document

Other files and links

Fingerprint

Cite this