N-Methylpyridinium 3-cyano-4-(dicyanomethylene)-5-oxo-4,5-dihydro-1H-pyrrol-2-olate

Abstract

The crystal structure of the title compound, C(6)H(8)N(+).C(8)HN(4)O(2)(-), is characterized by three independent ion pairs (A, B and C) in the asymmetric unit. Each ion pair consists of an anion and a cation, and the three ion pairs have similar geometric parameters. All the anions are arranged as dianion dimers via two N-H.O hydrogen bonds and the dimers form one-dimensional columns parallel to the b axis as a result of pi-pi interactions. The cations are also stacked, in two different ways: one type of stacking consists of alternating A and B cations, while the other type consists of C cations only. Each dianion dimer stack is surrounded by eight stacks of cations and is not connected directly to other dianion stacks.

Poly[[[diaquazinc(II)]-bis(μ2-3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olato-κ2N3:N3′)] dihydrate]

“…The geometry of the anion in (I) ( Table 1) is essentially identical to that found in other salts (Tafeenko et al, 2003(Tafeenko et al, , 2005Tafeenko, Nikolaev et al, 2004), although some minor differences are apparent. The C6ÐC7 and C6ÐC8 bonds are shorter than the corresponding bonds found in salts with different cations, namely potassium (Tafeenko et al, 2003), N,N-dimethylanilinium , N-methylpyridinium (Tafeenko, Nikolaev et al, 2004)…”

“…we proposed that this anion could be involved in %±% stacking interactions and that it could form coordination compounds. Subsequently, %±% stacking interactions have been detected not only between cations and this anion, but also between pairs of anions (Tafeenko et al, 2003(Tafeenko et al, , 2005Tafeenko, Nikolaev et al, 2004). We report here the ®rst example of a metal coordination compound, the title compound, (I), where the anion coordinates to Zn II (Fig.…”

Reaction of 2,2,3,3-Tetracyanocyclopropanecarboxylic Acid with Iodides. Synthesis of 3-Cyano-4-dicyanomethylidene-5-oxo-4,5-dihydro-1H-pyrrol-2-olates

“…The results showed radically different modes of crystal packing in these salts [7,8], which suggests prospects in continuing studies in this line. The results showed radically different modes of crystal packing in these salts [7,8], which suggests prospects in continuing studies in this line.…”

Ammonium 3-cyano-4-(dicyanomethylene)-5-oxo-4,5-dihydro-1H-pyrrol-2-olate monohydrate

“…All three salts have the same anion, namely 3-cyano-4-(dicyanomethylene)-5-oxo-4,5-dihydro-1H-pyrrol-2-olate, (I), but different cations, e.g. potassium, (II) (Tafeenko et al, 2003), N,N-dimethylanilinium, (III) , and N-methylpyridinium, (IV) (Tafeenko, Nikolaev et al, 2004), and show different types of molecular packing and aggregation. In the potassium salt, (II), the anions are connected via the cyano groups (%±% and dipole±dipole interactions) of the dicyanomethylene moieties.…”