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The Photochemistry of [CpMo(CO) 3 (η 1 ‐C 3 H 5 )] in Frozen Gas Matrices at 10 K and the Behaviour of [CpMo(CO) 2 (η 3 ‐C 3 H 5 )] Isomers in Different Media
Author(s) -
Limberg Christian,
Downs Anthony J.,
Greene Tim M.,
Wistuba Tobias
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200109)2001:10<2613::aid-ejic2613>3.0.co;2-6
Subject(s) - chemistry , cyclohexane , conformational isomerism , pentane , solvent , benzene , photodissociation , molecule , photochemistry , matrix isolation , computational chemistry , organic chemistry
On photolysis of [CpMo(CO) 3 (η 1 ‐C 3 H 5 )] in solid inert matrices at low temperature, one CO molecule is eliminated yielding the exo and endo isomers of [CpMo(CO) 2 (η 3 ‐C 3 H 5 )] in almost 1:1 proportions, although the fraction of the exo conformer is increased by prolonged broad‐band UV irradiation. If gaseous [CpMo(CO) 2 (η 3 ‐C 3 H 5 )] is isolated in an Ar matrix the proportions of the two conformers are again about 1:1, indicating that they possess almost equal energies, as confirmed by DFT calculations (B3LYP/SDD). This situation changes in a solvent environment, where increasing the polarity of the solvent favours the exo isomer, as indicated by the ratios exo / endo = 1.7:1 (pentane or cyclohexane), 3.0:1 (benzene) and 3.3:1 (CH 2 Cl 2 ) determined by IR and NMR measurements. Such a finding is consistent with the results of DFT calculations, which reveal that the exo isomer is more polar.