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

N,N′-methylenedipyridinium Pt(II) and Pt(IV) hybrid salts: synthesis, crystal and molecular structures of [(C₅H₅N)₂CH₂] · [PtCl₄] and [(C₅H₅N)₂CH₂] · [PtCl₆]

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: The highly insoluble organic-inorganic hybrid ionic compounds N,N′-methylenedipyridinium tetrachloroplatinate(II) [(C₅H₅N)₂CH₂] · [PtCl₄] and N,N′-methylenedipyridinium hexachloroplatinate(IV) [(C₅H₅N)₂CH₂] · [PtCl₆] were obtained by the treatment of N,N′-methylenedipyridinium dichloride monohydrate [(C₅H₅N)₂CH₂]Cl₂ · H₂O with K₂[PtCl₄] or (NH₄)₂[PtCl₆], respectively, in an aqueous solution. Both complexes were isolated, purified, characterised by elemental analysis, and their molecular structures were confirmed by powder X-ray diffraction. The crystal structure of both compounds consists of separated discrete dications [(C₅H₅N)₂CH₂]²⁺ and anions [PtCl _n ]²⁻ (n = 4 or 6). As anticipated, the dications formed a butterfly shape consisting of two pyridine rings bound to the methylene group via their N atoms, while the Pt centre had a square planar geometry in [(C₅H₅N)₂CH₂] · [PtCl₄] and an octahedral coordination in [(C₅H₅N)₂CH₂] · [PtCl₆]. Interestingly, both crystal structures are stabilised by intermolecular C-H…Cl non-standard hydrogen bonds, π-π ring interactions between two pyridine rings of adjacent dications, and also by Cl-π interactions.

Keywords: dications – N,N′-methylenedipyridinium – organic-inorganic hybrid salt – powder X-ray diffraction – Pt complex

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-012-0221-8

Chemical Papers 66 (11) 1032–1038 (2012)