ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis and crystal and molecular structures of N,N′-methylenedipyridinium tetrachlorozincate(II) and N,N′-methylenedipyridinium tetrachlorocadmate(II)

Mahmoud M. Al-Ktaifani and Mwaffak K. Rukiah

Department of Chemistry, Atomic Energy Commission, P.O. Box 6091, Damascus, Syria

E-mail: cscientific@aec.org.sy

Abstract: Treatment of N,N′-methylenedipyridinium dichloride [C₅H₅N-CH₂-NC₅H₅]Cl₂ with MCl₂ (M = Zn or Cd) in aqueous solution gives the organic-inorganic hybrid ionic compounds [C₅H₅N-CH₂-NC₅H₅] · [MCl₄]. Both complex salts were fully characterised by multinuclear NMR spectroscopy, elemental analysis, and their molecular structures confirmed by powder X-ray diffraction studies. The most striking feature in both solid state structures was the presence of the C…Cl-M short contacts between the organic [C₅H₅N-CH₂-NC₅H₅] dication and inorganic [MCl₄] anion, which led to different crystal packing. For [C₅H₅N-CH₂-NC₅H₅]·[ZnCl₄], the C…Cl-Zn interactions led to the alternating arrangement of [C₅H₅N-CH₂-NC₅H₅]²⁺[ZnCl₄]²⁻ to form 1-D chains in the direction [010], and each individual chain had a two-fold rotational axis along the b axis, while for [C₅H₅N-CH₂-NC₅H₅] · [CdCl₄] the C…Cl-Cd associations gave 2-D network. In both solid state structures, the presence of Cl-ring centroid distances gave a strong indication of some form of Cl-π interactions.

Keywords: organic-inorganic hybrid salt – N,N′-methylenedipyridinium – Zn – Cd complex – NMR – powder X-ray diffraction

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-011-0031-4

Chemical Papers 65 (4) 469–476 (2011)