"23" . "\u010Cern\u00FD, Ji\u0159\u00ED" . "25" . "5"^^ . "Study of the Origin of the Hindered Rotation of an Aryl Ring in the Chromium Aminocarbene Complexes Bearing Aromatic Ring Attached to the Carbene Carbon Atom."@en . "0276-7333" . "Study of the Origin of the Hindered Rotation of an Aryl Ring in the Chromium Aminocarbene Complexes Bearing Aromatic Ring Attached to the Carbene Carbon Atom." . . . . "22310" . "Pomoc\u00ED 1H NMR byly stanoveny bari\u00E9ry rotace arom\u00E1tu v cis-tetrakarbonyl[(h2-N-allyl-N-allylamino)(4-X-fenyl)carben]chromium(0) (X = MeO, Me, H, Cl, CO2Me and CF3) ."@cs . "Studium p\u016Fvodu br\u00E1n\u011Bn\u00E9 rotace arom\u00E1tu v aminokarbenov\u00FDch komplexech chromu nesouc\u00EDch aromatick\u00FD kruh v\u00E1zan\u00FD na karbenov\u00FD atom uhl\u00EDku."@cs . "5540-5548" . . "502322" . "Study of the Origin of the Hindered Rotation of an Aryl Ring in the Chromium Aminocarbene Complexes Bearing Aromatic Ring Attached to the Carbene Carbon Atom." . . "Dvo\u0159\u00E1k, Dalimil" . . "Tobrman, Tom\u00E1\u0161" . "Substituted chromium aminocarbene complexes cis-tetracarbonyl[(h2-N-allyl-N-allylamino)(4-X-phenyl)carbene]chromium(0) (X = MeO, Me, H, Cl, CO2Me and CF3) were prepared by the reaction of the corresponding N,N-diallylamides with Na2Cr(CO)5 and Me3SiCl. Using dynamic NMR, the rotational barrier of the aryl ring in these complexes was established. The obtained values are higher for the complexes bearing electron-acceptors compared to those bearing donor substituents and correspond with the Hammett equation. This indicates that the restricted rotation of aryl ring in the chromium aminocarbene complexes is a balance between steric and conjugation effects; while the former increases the barrier, the latter decreases it by stabilizing of the transition state of the rotation. This finding is compatible with the fact, that in the related cis-tetracarbonyl[(N-alkyl-h2-N-allylamino)(phenyl)carbene]chromium(0) complexes (alkyl = Me, Et and i-Pr) the rotational barrier grows steadily with the growing steric deman"@en . . "RIV/60461373:22310/06:00016996" . . . . "US - Spojen\u00E9 st\u00E1ty americk\u00E9" . . "P(GA203/00/1240), P(GA203/04/0487)" . "Chromium; Aminocarbenes; rotation barrier"@en . . . "Substituted chromium aminocarbene complexes cis-tetracarbonyl[(h2-N-allyl-N-allylamino)(4-X-phenyl)carbene]chromium(0) (X = MeO, Me, H, Cl, CO2Me and CF3) were prepared by the reaction of the corresponding N,N-diallylamides with Na2Cr(CO)5 and Me3SiCl. Using dynamic NMR, the rotational barrier of the aryl ring in these complexes was established. The obtained values are higher for the complexes bearing electron-acceptors compared to those bearing donor substituents and correspond with the Hammett equation. This indicates that the restricted rotation of aryl ring in the chromium aminocarbene complexes is a balance between steric and conjugation effects; while the former increases the barrier, the latter decreases it by stabilizing of the transition state of the rotation. This finding is compatible with the fact, that in the related cis-tetracarbonyl[(N-alkyl-h2-N-allylamino)(phenyl)carbene]chromium(0) complexes (alkyl = Me, Et and i-Pr) the rotational barrier grows steadily with the growing steric deman" . "Meca, Lud\u011Bk" . "RIV/60461373:22310/06:00016996!RIV07-GA0-22310___" . . "9"^^ . "4"^^ . "Studium p\u016Fvodu br\u00E1n\u011Bn\u00E9 rotace arom\u00E1tu v aminokarbenov\u00FDch komplexech chromu nesouc\u00EDch aromatick\u00FD kruh v\u00E1zan\u00FD na karbenov\u00FD atom uhl\u00EDku."@cs . . "Organometallics" . . "Study of the Origin of the Hindered Rotation of an Aryl Ring in the Chromium Aminocarbene Complexes Bearing Aromatic Ring Attached to the Carbene Carbon Atom."@en . "Dvo\u0159\u00E1kov\u00E1, Hana" . . "[ADA8448E9886]" . . .