Displaying all 15 publications

Abstract:
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  1. Balasubramani K, Fun HK
    PMID: 21583585 DOI: 10.1107/S1600536809027263
    The title compound, C(7)H(10)N(2)O(2)S, is essentially planar [maximum deviation 0.018 (4) Å]. In the crystal, mol-ecules are linked into chains by C-H⋯N hydrogen bonds and the chains are arranged in layers parallel to the ab plane.
  2. Fun HK, Balasubramani K
    PMID: 21583579 DOI: 10.1107/S1600536809027354
    In the title compound, C(5)H(8)N(3) (+)·C(7)H(4)NO(4) (-)·C(7)H(5)NO(4), the non-H atoms of the 3,4-diamino-pyridinium cation are coplanar, with a maximum deviation of 0.022 (1) Å. The carboxyl-ate and nitro groups of the 4-nitro-benzoate anion are twisted out of the attached ring planes by dihedral angles of 15.89 (8) and 10.20 (8)°, respectively. In the 4-nitro-benzoic acid mol-ecule, the carboxyl and nitro groups form dihedral angles of 18.25 (8) and 6.55 (8)°, respectively, with the benzene ring. In the crystal, the constituent units form two-dimensional networks parallel to (001) by O-H⋯O, N--H⋯O and C-H⋯O hydrogen bonds. Weak π-π inter-actions involving inversion-related 4-nitro-benzoic acid mol-ecules [centroid-centroid distance = 3.7325 (8) Å] and inversion-related 4-nitro-benzoate mol-ecules [centroid-centroid distance = 3.7124 (8) Å] are also observed.
  3. Balasubramani K, Fun HK
    PMID: 21583446 DOI: 10.1107/S1600536809024362
    In the title salt, C(5)H(8)N(3) (+)·C(7)H(6)NO(2) (-), the pyridine N atom of the 2,3-diamino-pyridine mol-ecule is protonated. The proton-ated N atom and one of the two N atoms of the 2-amino groups are hydrogen bonded to the 3-amino-benzoate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. The carboxyl-ate mean plane of the 3-amino-benzoate anion is twisted by 8.81 (7)° from the attached ring. The crystal structure is further stabilized by π-π inter-actions [centroid-centroid distance 3.6827 (7) Å].
  4. Balasubramani K, Fun HK
    PMID: 21582806 DOI: 10.1107/S160053680902100X
    In the title salt, C(5)H(8)N(3) (+)·C(7)H(4)NO(4) (-), the pyridine N atom of the 2,3-diamino-pyridine mol-ecule is protonated. The protonated N atom and one of the two 2-amino groups are hydrogen bonded to the 4-nitro-benzoate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. The carboxyl-ate mean plane of the 4-nitro-benzoate anion is twisted by 3.77 (5)° from the attached ring and the nitro group is similarly twisted by 2.28 (10)°. In the crystal, the mol-ecules are linked by N-H⋯O and C-H⋯O inter-actions into sheets parallel to (100).
  5. Fun HK, Balasubramani K
    PMID: 21582796 DOI: 10.1107/S1600536809020832
    In the title compound, C(5)H(8)N(3) (+)·C(7)H(5)O(3) (-), the pyridine N atom is protonated. In the 4-hydroxy-benzoate anion, the carboxyl-ate group is twisted slightly out of the benzene ring plane by an angle of 3.77 (5)°. The protonated N atom and one of the two amino groups are hydrogen-bonded to the 4-hydroxy-benzoate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. The crystal structure is further stabilized by O-H⋯O and C-H⋯O hydrogen bonds and π-π inter-actions involving the pyridinium rings [centroid-centroid distance of 3.6277 (5) Å], leading to the formation of a three-dimensional network.
  6. Fun HK, Balasubramani K
    PMID: 21582821 DOI: 10.1107/S1600536809021205
    In the title compound, C(5)H(8)N(3) (+)·C(4)H(5)O(4) (-), the pyridine N atom of the 3,4-diamino-pyridine mol-ecule is protonated. The protonated N atom participates in an N-H⋯O hydrogen bond to a succinate O atom of the singly deprotonated succinate anion. Each of the two amino groups are hydrogen-bonded to the O atoms of two different sets of succinate groups.. The crystal structure is further stabilized by O-H⋯O and C-H⋯O hydrogen bonds.
  7. Balasubramani K, Fun HK
    PMID: 21582810 DOI: 10.1107/S1600536809021011
    In the title compound, C(5)H(8)N(3) (+)·C(7)H(5)O(2) (-), the pyridine N atom is protonated. The carboxyl-ate group of the benzoate anion is twisted away from the attached ring by 10.91 (9)°. In the crystal structure, N-H⋯O hydrogen bonds between 2,3-diamino-pyridinium cations and benzoate anions, and π-π inter-actions between the pyridinium rings [centroid-centroid distance = 3.6467 (9) Å] form a two-dimensional network parallel to (001). In the network, N-H⋯O hydrogen bonds form R(2) (2)(8) and R(2) (1)(7) ring motifs.
  8. Fun HK, Balasubramani K, Yeap CS
    PMID: 21583553 DOI: 10.1107/S1600536809026439
    In the title salt, 2C(5)H(8)N(3) (+)·C(4)H(4)O(4) (2-)·3H(2)O, the asymmetric unit contains a protonated 2,3-diamino-pyridinium cation, half of a succinate dianion (disposed about a centre of inversion), and one and a half water mol-ecules. One of the water mol-ecules is disordered over two sites with occupancies of 0.670 (17) and 0.330 (17). The other water mol-ecule has an occupancy of 0.5 (from refinement). The pyridine N atom of the 2,3-diamino-pyridine mol-ecule is protonated. The protonated N atom and one of the 2-amino H atoms are hydrogen bonded to the succinate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. In the crystal, mol-ecules are consolidated into a three-dimensional network by N-H⋯O and O-H⋯O inter-actions.
  9. Thanigaimani K, Arshad S, Razak IA, Makeshvaran D, Balasubramani K
    PMID: 23795126 DOI: 10.1107/S1600536813013895
    The 4-methyl-benzoic acid mol-ecule of the title adduct, C10H11N5·C8H8O2, is approximately planar with a dihedral angle of 6.3 (2)° between the carb-oxy-lic acid group and the benzene ring. In the triazine mol-ecule, the plane of the triazine ring makes a dihedral angle of 29.2 (2)° with that of the adjacent benzene ring. In the crystal, the acid and base mol-ecules are linked via N-H⋯O and O-H⋯N hydrogen bonds with an R 2 (2)(8) motif, and the acid-base pairs are further connected via N-H⋯N hydrogen bonds with R 2 (2)(8) motifs, forming a supra-molecular ribbon along [101]. Between the tapes, a weak C-H⋯π inter-action is observed.
  10. Thanigaimani K, Farhadikoutenaei A, Arshad S, Razak IA, Balasubramani K
    Acta Crystallogr Sect E Struct Rep Online, 2012 Dec 1;68(Pt 12):o3415-6.
    PMID: 23476237 DOI: 10.1107/S1600536812046338
    The base mol-ecule of the title co-crystal, C7H10N2O2S·C7H6O3, is essentially planar, with a maximum deviation of 0.0806 (14) Å for all non-H atoms. The acid mol-ecule is also nearly planar, with a dihedral angle of 8.12 (14)° between the benzene ring and the carb-oxy group. In the crystal, the acid mol-ecules form an inversion dimer through a pair of O-H⋯O hydrogen bonds with an R2(2)(8) ring motif. The pyrimidine mol-ecules are linked on both sides of the dimer into a heterotetra-mer via O-H⋯N and C-H⋯O hydrogen bonds with R2(2)(8) ring motifs. The heterotetra-mers are further linked by weak C-H⋯O hydrogen bonds, forming a tape structure along [1-10].
  11. Thanigaimani K, Khalib NC, Razak IA, Lavanya P, Balasubramani K
    Acta Crystallogr Sect E Struct Rep Online, 2013 Jun 01;69(Pt 6):o968-9.
    PMID: 23795125 DOI: 10.1107/S1600536813013883
    The benzoic acid mol-ecule of the title adduct, C10H11N5·C7H6O2, is approximately planar, with a dihedral angle of 7.2 (3)° between the carb-oxy-lic acid group and the benzene ring. In the triazine mol-ecule, the plane of the triazine ring makes a dihedral angle of 28.85 (9)° with that of the adjacent benzene ring. In the crystal, the two components are linked by N-H⋯O and O-H⋯N hydrogen bonds with an R 2 (2)(8) motif, thus generating a 1 + 1 unit of triazine and benzoic acid mol-ecules. The acid-base units are further connected by N-H⋯N hydrogen bonds with R 2 (2)(8) motifs, forming a supra-molecular ribbon along [101]. The crystal structure also features weak π-π [centroid-centroid distances = 3.7638 (12) and 3.6008 (12) Å] and C-H⋯π inter-actions.
  12. Edison B, Balasubramani K, Thanigaimani K, Khalib NC, Arshad S, Razak IA
    Acta Crystallogr Sect E Struct Rep Online, 2014 Aug 1;70(Pt 8):o857-8.
    PMID: 25249908 DOI: 10.1107/S1600536814015220
    In the title mol-ecular salt, C4H6ClN4 (+)·C5H7O4 (-), the cation is essentially planar, with a maximum deviation of 0.037 (1) Å for all non-H atoms. The anions are self-assembled through O-H⋯O hydrogen bonds, forming a supra-molecular zigzag chain with graph-set notation C(8). In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds with an R 2 (2)(8) ring motif. This motif further self-organizes through N-H⋯O and O-H⋯O hydrogen bonds, generating an array of six hydrogen bonds, the rings having graph-set notation R 3 (2)(8), R 2 (2)(8), R 4 (2)(8), R 2 (2)(8) and R 3 (2)(8). In addition, another type of R 2 (2)(8) motif is formed by inversion-related pyrimidinium cations via N-H⋯N hydrogen bonds, forming a two-dimensional network parallel to (101).
  13. Jeevaraj M, Sivajeyanthi P, Edison B, Thanigaimani K, Balasubramani K, Razak IA
    Acta Crystallogr E Crystallogr Commun, 2017 Oct 01;73(Pt 10):1595-1598.
    PMID: 29250389 DOI: 10.1107/S2056989017013950
    In the title mol-ecular salt, 2C6H10N3O+·C8H4O42-, the N atom of each of the two 2-amino-4-meth-oxy-6-methyl-pyrimidine mol-ecules lying between the amine and methyl groups has been protonated. The dihedral angles between the pyrimidine rings of the cations and the benzene ring of the succinate dianion are 5.04 (8) and 7.95 (8)°. Each of the cations is linked to the anion through a pair of N-H⋯O(carboxyl-ate) hydrogen bonds, forming cyclic R22(8) ring motifs which are then linked through inversion-related N-H⋯O hydrogen bonds, giving a central R24(8) motif. Peripheral amine N-H⋯O hydrogen-bonding inter-actions on either side of the succinate anion, also through centrosymmetric R22(8) extensions, form one-dimensional ribbons extending along [211]. The crystal structure also features π-π stacking inter-actions between the aromatic rings of the pyrimidine cations [minimum ring centroid separation = 3.6337 (9) Å]. The inter-molecular inter-actions were also investigated using Hirshfeld surface studies and two-dimensional fingerprint images.
  14. Jeevaraj M, Sivajeyanthi P, Edison B, Thanigaimani K, Balasubramani K, Razak IA
    Acta Crystallogr E Crystallogr Commun, 2017 Sep 01;73(Pt 9):1305-1307.
    PMID: 28932461 DOI: 10.1107/S2056989017011252
    In the title mol-ecular salt, C6H10N3O(+)·C7H5O3(-), the cation is protonated at the N atom lying between the amine and methyl substituents and the dihedral angle between the carboxyl group and its attached ring in the anion is 4.0 (2)°. The anion features an intra-molecular O-H⋯O hydrogen bond, which closes an S(6) ring. The cation and anion are linked by two N-H⋯O hydrogen bonds [R2(2)(8) motif] to generate an ion pair in which the dihedral angle between the aromatic rings is 8.34 (9)°. Crystal symmetry relates two ion pairs bridged by further N-H⋯O hydrogen bonds into a tetra-meric DDAA array. The tetra-mers are linked by pairs of C-H⋯O hydrogen bonds to generate [100] chains. Hirshfeld surface and fingerprint plot analyses are presented.
  15. Sivajeyanthi P, Balasubramani K, Jeevaraj M, Thanigaimani K, Khalib NC, Razak IA
    Acta Crystallogr E Crystallogr Commun, 2015 Jun 01;71(Pt 6):o376-7.
    PMID: 26090174 DOI: 10.1107/S2056989015008397
    In the crystal of the title mol-ecular salt, C7H9N6O(+)·NO3 (-), the cations and anions are linked via N-H⋯O and O-H⋯O hydrogen bonds, forming sheets parallel to (100). Within the sheets there are numerous hydrogen-bonding ring motifs.
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