The Synthesis and Structure of Palladium 2,4-dimethyl-8-hydroselenoquinolinate

Abstract

The internal complex palladium 2,4-dimethyl-8-
hydroselenoquinolinate Pd[C9H4(CH3)2NSe]2 (I) has been
synthesized in the course of study of the complexing activity of 8-
hydroselenoquinoline and investigation of the nature of chemical
bond metal-selenium in the five-membered metal-containing ring.
X-ray diffraction data for I: Monoclinic, space group P21/n, a =
9.0092(4), b = 16.3290(7), c = 14.1073(6) Å,  = 106.710(2)o, V =
1987.7(2) Å3, Z = 4, R1=0.0477, wR2=0.1182 for 4499 reflections
(diffractometer Bruker-Nonius KappaCCD, MoK).
The crystal structure of the complex I is formed by neutral
asymmetric molecules Pd[C9H4(CH3)2NSe]2 in which the central
atom palladium is connected bidentically (Se,N) with two 2,4-
dimethyl-8-hydroselenoquinoline ligands. The structure of
palladium coordination polyhedron is cis-square (2Se+2N)
somewhat tetrahedrally distorted. Dihedral angle between the
SePdN / SePdN coordination planes is 20.15(1)o.
The Pd–Se and Pd–N bonds are covalent. The transition of
trans- (complex Pd(C9H6NSe)2 (II) to cis-coordination (complex I)
causes the weakening of the Pd–N bonds (compare 2.162(5) and
2.159(5) Å (I) , 2.065(3) Å (II) ).