Substituent Effects on Formation of Cation Dimers by Weak Hydrogen Bonds in Crystals of Carbonyl Pyridinium Salts of Ni(dmit)2

• Published in: Bulletin of the Chemical Society of Japan 2009, Vol.82 (9), p.1152-1159
• Main Authors: Tomono, Kazuaki, Koyano, Ayako, Morita, Takashi, Miyamura, Kazuo
• Format: Article
• Language: English
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.82.1152

Five 1:1 salts of 3-X-1-methylpyridinium (X = benzoyl, acetyl, methoxycarbonyl, carboxy, and aminocarbonyl; abbreviated as Ben, Ace, Met, Car, and Ami, respectively) cations with a [Ni(dmit)2]− anion ([Ben]+[Ni(dmit)2]− (1), [Ace]+[Ni(dmit)2]− (2), [Met]+[Ni(dmit)2]− (3), [Car]+[Ni(dmit)2]− (4), and [Ami]+[Ni(dmit)2]− (5)) have been synthesized and characterized by single-crystal X-ray analysis and conductivity measurements. In the crystals, three cations 1–3 were found to form dimers by weak C–H···O hydrogen bonds, and the arrangements of cations had a strong relation with the electronic effect of the substituents. The cations of 1–3 formed similar centrosymmetrically associated dimers constructed by weak C–H···O hydrogen bonds, whose geometric parameters had a correlation with the electronic effect of the substituents. A cation of 4 also formed centrosymmetrically associated dimer, but it was made by an O–H···O hydrogen bond as usually observed in the case of carboxylic acid. In contrast with other complex salts, cations of 5 formed one-dimensional structure by C–H···O hydrogen bonding. The conductivities of salts 1, 2, 3, 4, and 5 at room temperature were 1.00 × 10−6, 1.10 × 10−6, 2.86 × 10−6, 9.77 × 10−6, and 8.75 × 10−7 S cm−1, respectively.