Binuclear cyclopentadienylmolybdenum carbonyl derivatives: Where is the missing modMo Double-Bonded species Cp 2Mo 2(CO) 5?

Zhang Xiuhui; Li Qian-shu; Ge Maofa; Xie Yaoming; R. Bruce King; Henry F. Schaefer

doi:10.1021/om801170e

Binuclear cyclopentadienylmolybdenum carbonyl derivatives: Where is the missing modMo Double-Bonded species Cp ₂Mo ₂(CO) ₅?

Zhang Xiuhui, Li Qian-shu^*, Ge Maofa, Xie Yaoming, R. Bruce King, Henry F. Schaefer

^*Corresponding author for this work

School of Chemistry and Chemical Engineering

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

2 Citations (Scopus)

Abstract

The cyclopentadienylmolybdenum carbonyls Cp ₂Mo ₂(CO) _n (Cp = n ₅-C ₅H ₅; n = 6-1) have been studied by density functional theory. The two lowest energy structures predicted for Cp ₂Mo ₂(CO) ₆ lie within 4 kcal/mol of each other. Both have Mo-Mo single bonds of lengths 3.2-3.3 A° with all terminal carbonyl groups and correspond to stable compounds structurally characterized by X-ray diffraction. Similarly, the lowest energy structure predicted for Cp ₂Mo ₂(CO) ₄ has a formal Mo Mo triple bond of length ̃2.5 A° with four weakly semibridging carbonyl groups also corresponding to a stable compound structurally characterized by X-ray diffraction. The pentacarbonyl Cp ₂Mo ₂(CO) ₅, which is not known experimentally as a stable compound but only as a transient intermediate, is shown to have a structure with one symmetrical bridging two-electron donor and four terminal carbonyl groups as well as a formal Mo Mo double bond. Furthermore, Cp ₂Mo ₂(CO) ₅ is predicted to be thermodynamically unstable with respect to disproportionation into Cp ₂Mo ₂(CO) ₆ + Cp ₂Mo ₂(CO) ₄. The lowest energy structure for Cp ₂Mo ₂(CO) ₃ is a triplet with a formal MotMo triple bond. A higher energy singlet structure with one four-electrondonor bridging carbonyl group is also found for Cp ₂Mo ₂(CO) ₃. The MotMo bond distances in the lowest energy more highly unsaturated Cp ₂Mo ₂(CO) ₂ and Cp ₂Mo ₂(CO) structures suggest formal bond orders no higher than 3 in the lowest energy structures and thus metal atoms with less than the favored 18-electron configurations.

Original language	English
Pages (from-to)	2818-2829
Number of pages	12
Journal	Organometallics
Volume	28
Issue number	9
DOIs	https://doi.org/10.1021/om801170e
Publication status	Published - 11 May 2009

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10.1021/om801170e

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@article{3fb5e3ad2a434ff897dd15ea786ca171,

title = "Binuclear cyclopentadienylmolybdenum carbonyl derivatives: Where is the missing modMo Double-Bonded species Cp 2Mo 2(CO) 5?",

abstract = "The cyclopentadienylmolybdenum carbonyls Cp 2Mo 2(CO) n (Cp = n 5-C 5H 5; n = 6-1) have been studied by density functional theory. The two lowest energy structures predicted for Cp 2Mo 2(CO) 6 lie within 4 kcal/mol of each other. Both have Mo-Mo single bonds of lengths 3.2-3.3 A° with all terminal carbonyl groups and correspond to stable compounds structurally characterized by X-ray diffraction. Similarly, the lowest energy structure predicted for Cp 2Mo 2(CO) 4 has a formal Mo Mo triple bond of length{\~ }2.5 A° with four weakly semibridging carbonyl groups also corresponding to a stable compound structurally characterized by X-ray diffraction. The pentacarbonyl Cp 2Mo 2(CO) 5, which is not known experimentally as a stable compound but only as a transient intermediate, is shown to have a structure with one symmetrical bridging two-electron donor and four terminal carbonyl groups as well as a formal Mo Mo double bond. Furthermore, Cp 2Mo 2(CO) 5 is predicted to be thermodynamically unstable with respect to disproportionation into Cp 2Mo 2(CO) 6 + Cp 2Mo 2(CO) 4. The lowest energy structure for Cp 2Mo 2(CO) 3 is a triplet with a formal MotMo triple bond. A higher energy singlet structure with one four-electrondonor bridging carbonyl group is also found for Cp 2Mo 2(CO) 3. The MotMo bond distances in the lowest energy more highly unsaturated Cp 2Mo 2(CO) 2 and Cp 2Mo 2(CO) structures suggest formal bond orders no higher than 3 in the lowest energy structures and thus metal atoms with less than the favored 18-electron configurations.",

author = "Zhang Xiuhui and Li Qian-shu and Ge Maofa and Xie Yaoming and King, {R. Bruce} and Schaefer, {Henry F.}",

year = "2009",

month = may,

day = "11",

doi = "10.1021/om801170e",

language = "English",

volume = "28",

pages = "2818--2829",

journal = "Organometallics",

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publisher = "American Chemical Society",

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T1 - Binuclear cyclopentadienylmolybdenum carbonyl derivatives

T2 - Where is the missing modMo Double-Bonded species Cp 2Mo 2(CO) 5?

AU - Xiuhui, Zhang

AU - Qian-shu, Li

AU - Maofa, Ge

AU - Yaoming, Xie

AU - King, R. Bruce

AU - Schaefer, Henry F.

PY - 2009/5/11

Y1 - 2009/5/11

N2 - The cyclopentadienylmolybdenum carbonyls Cp 2Mo 2(CO) n (Cp = n 5-C 5H 5; n = 6-1) have been studied by density functional theory. The two lowest energy structures predicted for Cp 2Mo 2(CO) 6 lie within 4 kcal/mol of each other. Both have Mo-Mo single bonds of lengths 3.2-3.3 A° with all terminal carbonyl groups and correspond to stable compounds structurally characterized by X-ray diffraction. Similarly, the lowest energy structure predicted for Cp 2Mo 2(CO) 4 has a formal Mo Mo triple bond of length ̃2.5 A° with four weakly semibridging carbonyl groups also corresponding to a stable compound structurally characterized by X-ray diffraction. The pentacarbonyl Cp 2Mo 2(CO) 5, which is not known experimentally as a stable compound but only as a transient intermediate, is shown to have a structure with one symmetrical bridging two-electron donor and four terminal carbonyl groups as well as a formal Mo Mo double bond. Furthermore, Cp 2Mo 2(CO) 5 is predicted to be thermodynamically unstable with respect to disproportionation into Cp 2Mo 2(CO) 6 + Cp 2Mo 2(CO) 4. The lowest energy structure for Cp 2Mo 2(CO) 3 is a triplet with a formal MotMo triple bond. A higher energy singlet structure with one four-electrondonor bridging carbonyl group is also found for Cp 2Mo 2(CO) 3. The MotMo bond distances in the lowest energy more highly unsaturated Cp 2Mo 2(CO) 2 and Cp 2Mo 2(CO) structures suggest formal bond orders no higher than 3 in the lowest energy structures and thus metal atoms with less than the favored 18-electron configurations.

AB - The cyclopentadienylmolybdenum carbonyls Cp 2Mo 2(CO) n (Cp = n 5-C 5H 5; n = 6-1) have been studied by density functional theory. The two lowest energy structures predicted for Cp 2Mo 2(CO) 6 lie within 4 kcal/mol of each other. Both have Mo-Mo single bonds of lengths 3.2-3.3 A° with all terminal carbonyl groups and correspond to stable compounds structurally characterized by X-ray diffraction. Similarly, the lowest energy structure predicted for Cp 2Mo 2(CO) 4 has a formal Mo Mo triple bond of length ̃2.5 A° with four weakly semibridging carbonyl groups also corresponding to a stable compound structurally characterized by X-ray diffraction. The pentacarbonyl Cp 2Mo 2(CO) 5, which is not known experimentally as a stable compound but only as a transient intermediate, is shown to have a structure with one symmetrical bridging two-electron donor and four terminal carbonyl groups as well as a formal Mo Mo double bond. Furthermore, Cp 2Mo 2(CO) 5 is predicted to be thermodynamically unstable with respect to disproportionation into Cp 2Mo 2(CO) 6 + Cp 2Mo 2(CO) 4. The lowest energy structure for Cp 2Mo 2(CO) 3 is a triplet with a formal MotMo triple bond. A higher energy singlet structure with one four-electrondonor bridging carbonyl group is also found for Cp 2Mo 2(CO) 3. The MotMo bond distances in the lowest energy more highly unsaturated Cp 2Mo 2(CO) 2 and Cp 2Mo 2(CO) structures suggest formal bond orders no higher than 3 in the lowest energy structures and thus metal atoms with less than the favored 18-electron configurations.

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U2 - 10.1021/om801170e

DO - 10.1021/om801170e

M3 - Article

AN - SCOPUS:66149121786

SN - 0276-7333

VL - 28

SP - 2818

EP - 2829

JO - Organometallics

JF - Organometallics

IS - 9

ER -

Binuclear cyclopentadienylmolybdenum carbonyl derivatives: Where is the missing modMo Double-Bonded species Cp ₂Mo ₂(CO) ₅?

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