Hexakis(arylisocyano) derivatives of chromium(0) as initiators of vinyl polymerization: Steric effects

1985 ◽  
Vol 23 (1) ◽  
pp. 119-123 ◽  
Author(s):  
K. Hargreaves
Keyword(s):  
Steric Effects ◽  
Vinyl Polymerization ◽  
Derivatives Of

Conformational analysis and steric effects of substituents in derivatives of 3-oxo-, 3-imino-, and 3-methylenecyclohexene

1997 ◽  
Vol 46 (11) ◽  
pp. 1891-1896
Author(s):  
O. V. Shishkin ◽  
E. V. Solomovich ◽  
M. Yu. Antipin ◽  
A. S. Petrenko ◽  
L. A. Kutulya
Keyword(s):  
Conformational Analysis ◽  
Steric Effects ◽  
Derivatives Of

Nuclear magnetic resonance characterization of the ring conformations of monosubstituted derivatives of 1,3-dioxa-5,6-benzocycloheptene

1983 ◽  
Vol 61 (1) ◽  
pp. 109-115 ◽  
Author(s):  
R. St-Amour ◽  
M. St-Jacques
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Substituent Effects ◽  
Steric Effects ◽  
Slow Exchange ◽  
Conformational Properties ◽  
Derivatives Of ◽  
Ring Conformations ◽  
Twist Boat

The conformational properties of 2-alkyl (Me, Et, i-Pr, and t-Bu) and 2-phenyl derivatives of 1,3-dioxa-5,6-benzocycloheptene (1) were studied by 13C dnmr. Analysis of slow exchange spectra at 100.6 MHz indicates that all derivatives except tert-butyl exist in an equilibrium of chair (major) and twist-boat (minor) conformations. Substituent effects on the position of the equilibrium are rationalized in terms of steric effects.

Substituted carbonyl derivatives of the Group VI transition metals. II. Complexes with tritolylphosphines

1971 ◽  
Vol 24 (12) ◽  
pp. 2471 ◽  
Author(s):  
JA Bowden ◽  
R Colton
Keyword(s):  
Steric Effects ◽  
Molar Ratio ◽  
Mass Spectral Data ◽  
Group Vi ◽  
Mass Spectral ◽  
Carbonyl Derivatives ◽  
Nuclear Magnetic Resonance Spectra ◽  
Metal Hexacarbonyls ◽  
Cis And Trans ◽  
Derivatives Of

The reactions of the three tritolylphosphines (ortho, meta, and para) with the metal hexacarbonyls, M(CO)6 (M = Cr, Mo, W), have been investigated under a variety of conditions of temperature, ultraviolet irradiation, and molar ratio. The products were of the general formulae M(CO)5L and cis and trans M(CO)4L2 [L = tri-tolylphosphine] although not all the tetracarbonyl complexes could be prepared. Infrared and nuclear magnetic resonance spectra of these compounds showed interesting trends as the ligand was varied. ��� In addition, a novel series of derivatives with tri(o- tolyl)phosphine (pot) has been isolated, which on the basis of infrared, N.M.R., and mass spectral data are formulated as π- (pot)M(CO)3. ��� The nature of the above reactions and the properties of the products are explained in terms of an argument based on steric effects.

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