A 4-acyl-5-pyrazolone ligand (HQ) in N-unidentate coordination mode in a Rh(CO)2Cl(HQ)-type complex

Fifteen Years of Scientific Investigation into Main Groups and Transition Metal Coordination Chemistry with Allan White

The outcomes of the investigations on the structures and reactivity of a massive number of main group and transition metal complexes containing different families of ligands are reviewed. All the data result from the scientific collaboration between the research groups of Claudio Pettinari and Allan White which lasted fifteen years.

Can weak interactions modify the binding properties of a strong nitrogen donor? Unusual N-coordination of a phosphoranylidene-substituted pyrazolone unit towards palladium(ii) centres: an experimental and theoretical study

Selective N(2)-binding of 3-methyl-1-phenyl-4-(triphenylphosphoranylidene)-2-pyrazolin-5-one (L) has been found in two palladium(II) complexes, [PdCl(2)L(2)](2) and [Pd(o-C(6)H(4)CH(2)NMe(2))Cl](3). X-Ray diffraction studies show that the pyrazole rings lie almost perpendicular to the coordination plane. In both complexes the metal atom is located out of the plane defined by the pyrazole ring(s)(dihedral angle between the plane and the Pd-N vector approximately 30 degrees). To investigate the origin of this distortion, a theoretical study was carried out on a simplified model of complex , where a single pyrazolone ligand was replaced by NH(3). From this study it could be inferred that the out-of-plane distortion mainly involves weak, electrostatic interactions between a chlorine atom and an ortho-aromatic H atom of the N(1)-linked phenyl group, as well as between the other chlorine atom and an ortho-aromatic H atom of the PPh(3) group.