HINDERED LIGANDS IN TRANSITION-METAL COMPLEXES .39. SYNTHESIS AND DYNAMIC BEHAVIOR OF TETRACARBONYL-ETA-4-TRICYCLO[6.3.0.0(2.7)]UNDECA-3,5-DIENE METAL(0) COMPLEXES AND DICARBONYL-BIS-(ETA-4-TRICYCLO[6.3.0.0(2.7)]UNDECA-3,5-DIENE METAL(0) COMPLEXES OF THE ELEMENTS CHROMIUM, MOLYBDENUM AND TUNGSTEN

ÖZKAR S., TUNALI N., KREITER C.

JOURNAL OF ORGANOMETALLIC CHEMISTRY, vol.428, no.3, pp.345-351, 1992 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 428 Issue: 3
  • Publication Date: 1992
  • Doi Number: 10.1016/0022-328x(92)83097-2
  • Journal Name: JOURNAL OF ORGANOMETALLIC CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.345-351
  • Middle East Technical University Affiliated: Yes

Abstract

The hexacarbonyls of chromium, molybdenum, and tungsten react with tricyclo[6.3.0.0(2,7)]undeca-3,5-diene upon UV irradiation in a first step to tetracarbonyl-eta-4-tricyclo[6.3.0.0(2.7)]undeca-3,5-diene-chromium(0) (1), -molybdenum(0) (2) and -tungsten(0) (3). By longer irradiation, dicarbonyl-bis(eta-4-tricyclo[6.3.0.0(2.7)]undeca-3,5-diene)molybdenum(0) (4) and -tungsten(0) (5) are formed. The complexes were purified by chromatography and studied by IR, H-1, and C-13 NMR spectroscopy. The C-13 NMR signals of the CO ligands of 1-3 were found to be temperature dependent owing to a hindered CO scrambling. The H-1 and C-13 NMR signals of 4 and 5 are temperature dependent as well and indicate a hindered enantiomerization of the pseudo-octahedral complexes.