Ligands metal-ligand rotation

The metal is bound to a dummy atom at the centroid of the five-membered rings (Fig. 14.2(c)). The rotation of the ligands around the ligand-metal-ligand axis is easily achieved, and this topology is a reasonable model for the bond-... 

The values of the force constants of BzjCr for ligand-metal-ligand bending-, ligand tilting-, and internal rotation are very close to those of ferrocene. The corresponding constants of BzCr(CO)3 are somewhat different, a feature that might also be related to (unavoidable) differences in the definitions of the internal coordinates. 

Diasteroisomers, also known as geometric isomers, have different relative orientations of their metal-ligand bonds. Enantiomers are stereoisomers whose molecules are nonsuperposable mirror images of each other. Enantiomers have identical chemical and physical properties except for their ability to rotate the plane of polarized light by equal amounts but in opposite directions. A solution of equal parts of an optically active isomer and its enantiomer is known as a racemic solution and has a net rotation of zero. 

The activation barrier to rotation of the cyclopropenyl ligand about the M—C3 axis has been shown to vary dramatically with the nature of the metal-ligand fragment309,314 329. 

It is therefore of interest to note that RN=S=NR and RN=S=0 ligands may also rotate about the metal- )2-N=S bond in Pt(PPh3)2(RNSNR).20 Furthermore, it has been demonstrated for Pt(PPh3)2(RNSNR) that between —30 and +30°C the Pt(PPh3)2 moiety may glide from one n-N=S to the other and vice versa, probably via an S-bonded intermediate.20... 

The rotation around a metal-ligand single bond is free1391 i. e. /t 2 = 0. 

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