Vibrational spectra and structure of {open_quotes}staircase{close_quotes} carbonyl {pi}-complexes of transition metals 1. Electronic effects

Journal Article · Mon May 01 04:00:00 EDT 1995 · Russian Chemical Bulletin

OSTI ID:75660

Ezernitskaya, M G; Lokshin, B V; Orlova, T Yu; Setkina, V N ^[1]; Cesaro, S N ^[2]

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1. A.N. Nesmeyanov Institute of Organoelement Compounds, Moscow (Russian Federation)
2. Institute of High Temperature Thermodynamics, Rome (Italy)

FTIR spectra have been studied for {open_quotes}staircase{close_quotes} cyclopentadienyl complexes comprising two or three metal carbonyl fragments bound by the metal-carbon bond Cp(CO){sub 2}Fe-CpmMn(CO){sub 3}, Cp(CO){sub 2}Fe-CpmFe(CO){sub 2}CH{sub 2}Ph, Cp(CO){sub 2}Fe-Cpm(CO){sub 2}Fe-CpmMn(CO){sub 3}, Cp(CO){sub 2}Mo-Cpm(CO){sub 2}Fe-CpmMn(CO){sub 3}, Cp(CO){sub 3}W-Cpm(CO){sub 2}Fe-CpmMn(CO){sub 3}, Cp(CO){sub 2}Fe-Cpm(CO){sub 2}Fe-BmCr(CO){sub 3}, Cr(CO){sub 3}Bm-CpmFe(CO){sub 2}CH{sub 2}Ph, where Cp = {eta}{sup 5}-C{sub 5}H{sub 5}, Cpm = {eta}{sup 1}: {eta}{sup 5}-C{sub 5}H{sub 4}, Bm = {eta}{sup 1}:{eta}{sup 6}-C{sub 6}H{sub 5}, as well as mononuclear model complexes Cp(CO){sub 2}Fe(CH){sub 2}Ph, CpMn(CO){sub 3}, and ({eta}{sup 6}-C{sub 6}H{sub 6})Cr(CO){sub 3}. The spectra were interpreted on the basis of the local symmetry of each metal carbonyl center. The positions of vCOs are determined by the mutual electronic effect of each center. CpmM(CO){sub n} groups are strong electron acceptors and cause an increase in vCOs of adjacent M(CO){sub n} groups. Cp(CO){sub n}M groups, being electron donors, cause a decrease in the frequencies of neighboring groups. In trinuclear complexes, the frequencies of the central Fe(CO){sub 2} group are not changed much due to the compensation of donor and acceptor influences of two neighboring substituents.

• OSTI ID: 75660
• Journal Information: Russian Chemical Bulletin, Journal Name: Russian Chemical Bulletin Journal Issue: 11 Vol. 43; ISSN RCBUEY; ISSN 1066-5285
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ABSORPTION SPECTROSCOPY
CARBONYLS
CHROMIUM COMPLEXES
ELECTRONIC STRUCTURE
IRON COMPLEXES
MANGANESE COMPLEXES
MOLECULAR STRUCTURE
MOLYBDENUM COMPLEXES
ORGANOMETALLIC COMPOUNDS
TUNGSTEN COMPLEXES
VIBRATIONAL STATES