Strong and Weak Hydrogen-Bonding Interactions in the Structures of N,N‘,N‘ ‘-Trisubstituted Guanidinium Chlorides and Bromides

Abstract

The reaction of two trisubstituted guanidines N,N‘,N‘ ‘- triisopropylguanidine (TPG) and N,N ‘-diisopropyl-N‘ ‘-2,6-dimethylphenylguanidine (DPArG) with HX or equivalents (X = Cl, Br) yielded the anticipated guanidinium halide salts. The structures of TPGH+X- (X = Cl, 1), TPGH+X-·H2O (X = Br, 3·H2O), and DPArGH+X- (X = Cl, 2; Br, 4) were determined by single-crystal X-ray diffraction analysis to examine the potential intermolecular interactions in these compounds and their influence on the extended structures that were observed. The formation of strong, charge-assisted hydrogen bonds, NH+···X-, dominates the extended structures. In addition, weaker interactions between the N-substituents and between the X- anions and CH bonds of the substituents have an apparent role in the structures of these materials. While the TPGH+ cation displayed a C 3 propeller-type orientation in the structures of 1 and 3 ·H2O, two different isomeric forms for the less symmetric DPArGH+ cations were observed, and the identity of the anion and of the substituents both appear to be important in determining which form is obtained. Although the DPArGH+ cation exhibited different isomeric structures in 2 and 4, a common structural motif consisting of hydrogen-bonded chains was observed in their solid-state structures.

Bis(N,N′,N′′-triisopropylguanidinium) fumarate–fumaric acid (1/1)

“…1). The bond distances and bond angles in the title compound agree very well with the corresponding bond distances and bond angles reported in a similar compound earlier (Said et al, 2005). The central guanidinium fragment of the cation is planar (sum of NCN angles is 360°).…”

“…In connection with ongoing studies of the structural aspects of N,N′,N"-trisubstituted guanidinium salts (Said et al, 2011), we herein report the crystal structure of the title compound (Fig. 1).…”

“…For background information and N,N 0 ,N"-trisubstituted guanidinium salts, see: Said et al (2011). For related structures, see: Said et al (2005); Hemamalini & Fun (2010); Bü yü kgü ngö r et al (2004).…”

“…For related structures, see: Said et al (2005); Hemamalini & Fun (2010); Bü yü kgü ngö r et al (2004). For the preparation of the triisopropyl guanidine compound, see : Ong et al (2003).…”

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds

“…However, Ru-S (2.1919 (7) These are considered as weak to medium hydrogen bonds [25,26]. The hydrogen bondings are principally observed between one of the H atoms of the phenyl ring of the xantphos ligand and the Cl atom of the complex.…”