3,4-Diaminopyridine

Abstract

Key indicatorsSingle-crystal X-ray study T = 120 K Mean (C-C) = 0.003 Å R factor = 0.036 wR factor = 0.081 Data-to-parameter ratio = 8.4For details of how these key indicators were automatically derived from the article, see

Crystal structure, optical and magnetic properties of the bis(perchlorate) of 3,4-diaminopyridine

“…In the case of the hydrogensquarate salt of 34-DAP [15], interactions of the types NHÁÁÁO=C (Sq) with a bond length of 2.800 Å and NH 2 ÁÁÁO=C (Sq) with bond lengths of 2.969 and 2.974 Å are observed, while in 3,4-diaminopyridinium hydrogentartarate dihydrate [16] a 3D network with molecules linked by intermolecular NHÁÁÁOH 2 (2.807 Å ), HNHÁÁÁOH 2 (3.037 Å ), HNHÁÁÁOCO (3.007 Å ), HOHÁOCO (2.680 Å ), OHÁÁÁOH 2 (2.789 Å ), and HOHÁÁÁOH (2.747 Å ) hydrogen bonds with participation of cations, anions, and solvent molecules is obtained. It is in contrast to neutral 3,4-DAP [14], where both the 3-and 4-NH 2 substituents participate in symmetric intermolecular hydrogen bonding of the type HNHÁÁÁN with bond lengths of 2.258, 2.228 Å (for 4-NH 2 ) and 2.327 and 2.496 Å (for 3-NH 2 ). The molecule of the cation is flat with a maximal deviation from total planarity less than 0.2°.…”

“…3 is compared with the corresponding one of neutral molecule and its N1 protonated form [14][15][16]. In contrast to N1 monoprotonated salts [15,16], the N1, N4 diprotonation leads in the calculated IR-spectrum to an observation of the highest frequency bands, corresponding to asymmetric and symmetric stretches (m as NH 2 and m s NH 2 ) of 3-NH 2 group at 3,560 and 3,461 cm -1 .…”

“…Despite the proved biological activity of 3,4-diaminopyridine (34-DAP, Scheme 1(1)), structural investigations of its salts are rare. The crystal structure of neutral compound has been reported [14] and two N1 protonated salts (Scheme 1(2)) with hydrogensquarate and hydrogentartarate anions [15,16]. For last two compounds, it has been discussed that the N1 protonation leads to a partial distortion of the aromatic character of pyridine ring, similar to that observed for 4-aminopyridinium salt [17,18].…”

Quantum Chemical Approach on the Molecular Structural Properties of Some Aminopyridines

“…The computed bond parameters of the preferred optimized geometry of the chosen molecules at DFT level with 6-311G+ + (d, p) basis set are summarized in the Table-1in addition to the experimental parameters [18] for comparative purpose. Values taken from Ref.…”

“…Values taken from Ref. [18] Molecular symmetry is a fundamental concept as it is a tool to predict the properties such as dipole moment, planar structure of aromatic ring and electronic transitions in the molecules. It is observed that the mean C-C bond distance estimated in between the carbon atoms of the pyridine ring are found to be 1.395Å, 1.397 Å, 1.396 Å and 1.388 Å for 2AP, 3AP, 4AP and 34DAP respectively and these values are not significantly deviated from one another although they contain -NH 2 group at different positions.…”