PalladiumII and platinumII complexes with heteroditopic 10-(aryl)phenoxarsine (aryl = 2-C6H4OR, R = H, Me, Pr(i)) ligands: solvent-oriented crystallization of cis isomers

The synthesis and characterization of 10-(o-alkoxyphenyl)phenoxarsines 2-ROC6H4As(C6H4)2O (R = H, Me, and Pri, As(C6H4)2O = phenoxarsine) and their platinum(II) and palladium(II) complexes cis-PtCl2{2-PriOC6H4As(C6H4)2O-kappaAs}2] (1), trans-PdCl2{2-PriOC6H4As(C6H4)2O-kappaAs}2] (2), cis-PtCl2{2-HOC6H4As(C6H4)2O-kappaAs}2] (3), cis-PdCl2{2-HOC6H4As(C6H4)2O-kappaAs}2] (4), cis-PtI2{2-MeOC6H4As(C6H4)2O-kappaAs}2] (5), and trans-PdCl2{2-MeOC6H4As(C6H4)2O-kappaAs}2] (6) are reported. The chelate complex cis-Pt{2-OC6H4As(C6H4)2O-kappaAs,O}2] (7) is also described. The molecular structures of 1-4 and 7 were determined. The short As...O intramolecular interaction found in complexes 1-4 in the solid state was also verified by calculations at the B3LYP/LANL2DZ level for complex 2 and for 10-(o-isopropoxyphenyl)phenoxarsine in the gas phase, and this suggests that the interaction is a characteristic of the ligand rather than a packing effect. Calculations at the B3LYP/LANL2DZ and Oniom(B3LYP/LANL2DZ:uff) levels for complexes 1-4 showed that the solvent plays a crucial role in the crystallization (through geometry constraints) of the kinetically stable cis isomers.