Antisymbiotic effect

Thus it appears that the presence of two soft carbons on the palladium stabilizes the trans coordination of hard ligands and drives the selective coordination of ambidente ligands through their hardest atom. These results, as those described in the previous scheme, constitute other examples of the antisymbiotic effect which can be observed in soft palladium(II) complexes. 

The pyridylphosphole ligands possess two coordination centers with different stereoelectronic properties which, in accordance with the Pearson antisymbiotic effect [16c], allows the control the orientation of a second chelating ligand in the... 

One key property of pyridylphosphole ligands is their heteroditopic nature. They possess two coordination centers with different stereo-electronic properties, which, in accordance with Pearson s antisymbiotic effect [42a], can control the orientation of a second chelating ligand in the coordination sphere of a square-planar d8-metal center [42b]. This property has been exploited in order to control the in-plane parallel arrangement of ID-dipolar chromophores [42d]. Phospholes... 

Pearson noted that an antisymbiotic effect is also operative and explained this on the basis of a trans influence two soft Ugands in mutually trans positions will have a destabilizing effect on each other when attached to soft metal atoms. Linearly dicoordinated LAu(CNS) complexes exemplify this effect. (Hereafter, CNS represents the thiocyanate ligand without specifying the coordination mode.) Although only the S-bonded isomer of each complex is present in the solid state, the N-bonded isomers of some complexes were found to coexist in a variety of solvents. The Au— NCS/Au—SCN ratio determined as the integrated intensity ratio of the v(CN) absorption increases... 

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