The crystal and molecular structures of catena[bis(m2-chloro)- (m2-pyridazine-N,N0)]cadmium(II) and catena[bis(m2-chloro)- (m2-pyridazine-N,N0)]mercury(II) and the solid-phase 13C, 15N NMR studies of Zn(II), Cd(II), Hg(II) chloride complexes with pyridazi

The zinc triad metal chloride complexes with pyridazine of [M(pyridazine)Cl2]n type, M ¼ Zn(II) (1), Cd(II) (2), Hg(II) (3), were synthesized. The crystal and molecular structures of 2 and 3 were studied by single crystal X-ray diffraction. They are isostructural polymers of formulae catena[bis(m2-chloro)-(m2-pyridazine-N,N0)]cadmium(II) and catena[bis(m2-chloro)-(m2-pyridazine-N,N0)]mercury(II). They crystallize in the orthorhombic Imma space group (2: a ¼ 7:056ð1Þ; b ¼ 7:447ð1Þ; c ¼ 13:113ð1Þ A ° ; 3: a ¼ 7:129ð1Þ; b ¼ 7:398ð1Þ; c ¼ 13:073ð2Þ A ° ). The central atoms have the geometry of square bipyramid and are bridged by axial pyridazines and equatorial chlorides. The Cd–N and Hg–N bonds are 2.371(3) and 2.407(5) A ° , the Cd–Cl and Hg–Cl being 2.6279(7) and 2.6626(12) A ° , respectively. The X-ray powder diffractograms suggest 1 has a similar structure, being different from the monomeric species Zn(pyridazine)2Cl2 (4), already described by several authors as the sole product of ZnCl2 þ pyridazine reaction. The 15N CPMAS-NMR measurements of 1–3 reveal significant shielding (65–90 ppm) of nitrogen nuclei upon the formation of coordination bondings, the observed low-frequency shifts decreasing with the atomic mass of the metal. q 2004 Published by Elsevier B.V.