HINDERED LIGAND MOTIONS IN TRANSITION-METAL COMPLEXES .18. SYNTHESIS AND DYNAMIC BEHAVIOR OF TRICARBONYL(ETA-DIENE)(TRIMETHYLPHOSPHANE)CHROMIUM(0) AND TRICARBONYL(ETA-DIENE)(TRIMETHYL PHOSPHITE)CHROMIUM(0)

1983-01-01
KOTZIAN, M
KREITER, CG
MICHAEL, G
Özkar, Saim
Irradiation of Cr(CO)5[P(CH3)3] or Cr(CO)5[P(OCH3)3] in presence of 1,3‐butadiene (1), trans‐1,3‐pentadiene (2), and 2‐ethyl‐1,3‐butadiene (3), trans, trans‐2,4‐hexadiene (4), 2‐methyl‐1,3‐pentadiene (5), and 2‐ethyl‐1,3‐butadiene (6) produces in good yields Cr(CO)3L(η4‐diene) complexes (LP(CH3)3 1A–6A; LP(OCH3)3 1B–6B). The configurations of these complexes were determined by IR and NMR spectroscopy (1H, 13C, 31P). Cr(CO)3[P(OCH3)3](η4‐1,3‐pentadiene) (2B) and Cr(CO)3[P(OCH3)3](η4‐2,4‐hexadiene) (4B) form a mixture of two possible facial stereoisomers a and f. The other complexes favour only the a‐form. 2B and 4B show two different, intramolecular hindered ligand movements: Isomerization of the a‐ and f‐forms and carbonyl scrambling. Carbonyl scrambling is also observed for all the other complexes. The barriers of activation of these movements are around 40 and 50 kJ. mol−1, respectively. Transition states of trigonal prismatic geometries are suitable models to explain these movements.
Citation Formats
M. KOTZIAN, C. KREITER, G. MICHAEL, and S. Özkar, “HINDERED LIGAND MOTIONS IN TRANSITION-METAL COMPLEXES .18. SYNTHESIS AND DYNAMIC BEHAVIOR OF TRICARBONYL(ETA-DIENE)(TRIMETHYLPHOSPHANE)CHROMIUM(0) AND TRICARBONYL(ETA-DIENE)(TRIMETHYL PHOSPHITE)CHROMIUM(0),” pp. 3637–3658, 1983, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/69982.