In complexes with the uranyl dication, salophen ligands are highly puckered. This implies that nonsymmetric substituted uranyl-salophen derivatives exist in principle as a pair of enantiomers. However, due to easy disrotations about the bonds connecting the phenoxide units to the imine carbons, the rate of interconversion between enantiomeric forms of simple, sterically unhindered compounds is extremely fast. Bulky substituents in appropriate positions decrease the interconversion rate and make this novel type of inherent chirality detectable by 1H and 13C NMR. Thus, uranyl complexes of salophen-type 1:1:1 Schiff bases from 3-isopropylsalicylaldehyde and 2-hydroxybenzophenone with 1,2-diaminobenzene and 3,4,5,6-tetramethyl-1,2-diaminobenzene were prepared and studied by 1H and 13C NMR.
Unprecedented Detection of Inherent Chirality in Uranyl-Salophen Complexes
2003
Abstract
In complexes with the uranyl dication, salophen ligands are highly puckered. This implies that nonsymmetric substituted uranyl-salophen derivatives exist in principle as a pair of enantiomers. However, due to easy disrotations about the bonds connecting the phenoxide units to the imine carbons, the rate of interconversion between enantiomeric forms of simple, sterically unhindered compounds is extremely fast. Bulky substituents in appropriate positions decrease the interconversion rate and make this novel type of inherent chirality detectable by 1H and 13C NMR. Thus, uranyl complexes of salophen-type 1:1:1 Schiff bases from 3-isopropylsalicylaldehyde and 2-hydroxybenzophenone with 1,2-diaminobenzene and 3,4,5,6-tetramethyl-1,2-diaminobenzene were prepared and studied by 1H and 13C NMR.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
