Structural, Spectroscopic Investigation and Computational Study on Nitrate and Hydrogen Oxalate Salts of 2-Aminopyrimidine.

The proton transfer salts of 2-aminopyrimidine with nitric acid (2APNO) and oxalic acid (2APOX) were synthesized and crystallized successfully by solvent evaporation solution growth technique. The crystal packing is stabilized through intricate three dimensional hydrogen bonded network. Both, the molecular structures were optimized with Density Functional Theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311++G(d,p) basis set. Optimized molecular parameters between the methods were compared for the cation showing appreciable agreement. The computed vibrational spectra are compared with experimental result which clearly demonstrates the strong N-H··· O vibrational behaviour. Thermal stability of the crystals were analyzed with TGA/DTA and the melting points of the salts, viz. 2APNO and 2APOX, were identified at 189.5 and 210.9 °C, respectively. The chemical hardness, electronegativity, chemical potential and electrophilicity index of the two crystals were determined by HOMO-LUMO plot. The lower band gap value obtained from the Frontier Molecular Orbital (FMO) analysis favours the possible pharmaceutical/biological activity of the salts.

Investigation of Electrochemical Studies of Magnesium Ion Conducting Poly(vinyl alcohol)-Poly(vinyl pyrrolidone) Based Blend Polymers.

Polymer blend electrolytes based on magnesium ion conducting PVA-PVP-MgCl2 polymer were prepared at different compositions by solution casting techniques. The prepared films were characterised by various techniques such as XRD and FTIR. Amorphous nature and structural coordination of polymer electrolyte were confirmed by X-ray diffraction and Fourier transform infrared spectroscopy studies. The ionic conductivity of the prepared polymer electrolytes were analysed through ac impedance spectroscopy. The highest conductivity was found to be in the order of ~10-6 Scm-1 at an ambient temperature for the composition of 50PVA:50PVP:5 wt% MgCl2. Conductivity versus temperature plot was found to follow an Arrhenius nature. The dielectric behaviour and ionic transport properties of the polymer electrolytes were also analyzed.

Ethyl 3-(4-chloro-benzo-yl)-1-(4-chloro-benz-yl)-4-(4-chloro-phen-yl)-2,2-dioxo-3,4,6,7,8,8a-hexa-hydro-1H-pyrrolo-[2,1-c][1,4]thia-zine-1-carboxyl-ate.

In the title compound, C30H28Cl3NO5S, the pyrrolidine ring adopts an envelope conformation (with the N atom as the flap) and the thia-zine ring is in a distorted chair conformation. The mol-ecular structure shows three intra-molecular C-H⋯O inter-actions leading to self-associated ring S(6) and two S(7) motifs. In the crystal, the molecules are linked by C-H⋯O and C-H⋯Cl inter-actions. Two R 2 (2)(10) and one R 2 (2)(16) centrosymmetrically related ring motifs are observed in the unit cell and they are connected through C(6) and C(11) chain motifs extending along the b and c axes, respectively.

(E)-3-(4-Meth-oxy-phen-yl)-3-[3-(4-meth-oxy-phen-yl)-1H-pyrazol-1-yl]prop-2-enal.

In the title mol-ecule, C20H18N2O3, the pyrazole ring forms a dihedral angle of 2.2 (1)° with its meth-oxy-phenyl substituent and a dihedral angle of 67.2 (1)° with the benzene substituent on the propenal unit. In the crystal, mol-ecules are connected by weak C-H⋯O hydrogen bonds, forming R 2 (2)(26) and R 2 (2)(28) cyclic dimers that lie about crystallographic inversion centres. These dimers are further linked through C-H⋯O and C-H⋯N hydrogen bonds, forming C(8), C(9), C(10) and C(16) chain motifs. These primary motifs are further linked to form secondary C 2 (2)(15) chains and R 2 (2)(18) rings.

1-(2,4-Dinitro-phen-yl)-3-phenyl-4-phenyl-sulfanyl-1H-pyrazole.

In the title mol-ecule, C(21)H(14)N(4)O(4)S, the pyrazole ring forms dihedral angles of 45.6 (1), 87.7 (1) and 27.4 (1)° with the phenyl, sulfur-substituted benzene and nitro-substituted benzene rings, respectively. In the crystal, mol-ecules are connected by weak C-H⋯O and C-H⋯N hydrogen bonds into layers parallel to (010).

4-Chloro-anilinium 3-carb-oxy-prop-2-enoate.

In the title compound, C(6)H(7)ClN(+)·C(4)H(3)O(4) (-), the cations and anions lie on mirror planes and hence only half of the mol-ecules are present in the asymmeric unit. The 4-chloro-anilinium cation and hydrogen maleate anion in the asymmetric unit are each planar and are oriented at an angle of 15.6 (1)° to one another and perpendicular to the b axis. A characterestic intra-molecular O-H⋯O hydrogen bond, forming an S(7) motif, is observed in the maleate anion. In the crystal, the cations and anions are linked by N-H⋯O hydrogen bonds, forming layers in the ab plane. The aromatic rings of the cations are sandwiched between hydrogen-bonded chains and rings formed through the amine group of the cation and maleate anions, leading to alternate hydro-phobic (z = 0 or 1) and hydro-philic layers (z = 1/2) along the c axis.

Creatininium 2-chloro-acetate.

IN THE TITLE COMPOUND (SYSTEMATIC NAME: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 2-chloro-acetate), C(4)H(8)N(3)O(+)·C(2)H(2)ClO(2) (-), the mol-ecular aggregations are stabil-ized through classical (N-H⋯O) and non-classical (C-H⋯O and C-H⋯N) hydrogen-bonding inter-actions. The cations are linked to the anions, forming ion pairs through two N-H⋯O bonds that produce characteristic R(2) (2)(8) ring motifs. These cation-anion pairs are connected through another N-H⋯O hydrogen bond, leading to an R(4) (2)(8) ring motif. Further weak C-H⋯N inter-actions link the mol-ecules along the a axis, while other C-H⋯O inter-actions generate zigzag chains extending along b.

Creatinium hydrogen oxalate.

The crystal structure of the title compound, C(4)H(10)N(3)O(2) (+)·C(2)HO(4) (-), is stabilized by N-H⋯O and O-H⋯O hydrogen bonds. The anions are connected by an O-H⋯O hydrogen bond, leading to C(5) chain extending along c axis. The cations are dimerized around the corners of the unit cell, leading to an R(2) (2)(14) ring motif. This leads to a cationic mol-ecular aggregation at x = 0 or 1 and an anionic mol-ecular aggregation at x = 1/2.

A triclinic polymorph of 3-nitro-anilinium chloride.

The asymmetric unit of the title compound, C(6)H(7)N(2)O(2) (+)·Cl(-), contains two independent ion pairs. A monoclinic form of the title compound with only one ion pair in the asymmetric unit has been reported previously [Ploug-Sørensen & Andersen (1986). Acta Cryst. C42, 1813-1815]. In the crystal of the title compound, the components are linked into layers parallel to (001) by inter-molecular N-H⋯Cl hydrogen bonds, with alternating hydro-philic and hydro-phobic regions.

Diethyl 1-benzyl-2,2-dioxo-4-phenyl-3,4,6,7,8,8a-hexa-hydro-1H-pyrrolo-[2,1-c][1,4]thia-zine-1,3-dicarboxyl-ate.

In the title compound, C(26)H(31)NO(6)S, the five-membered pyrrolidine ring adopts an envelope conformation and the six-membered thia-zine ring is in a distorted chair conformation. The crystal packing is stabilized through an inter-molecular C-H⋯O inter-action, generating inversion-related R(2) (2)(10) ring motifs.

Creatininium cinnamate.

THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND (SYSTEMATIC NAME: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 3-phenyl-prop-2-enoate), C(4)H(8)N(3)O(+)·C(9)H(7)O(2) (-), is stabilized by N-H⋯O hydrogen bonding. Cations are linked to anions to form ion pairs with an R(2) (2)(8) ring motif. These ion pairs are connected through a C(2) (2)(6) chain motif extending along the c axis of the unit cell. This crystal packing is characterized by hydro-phobic layers at x âˆ¼ 1/2 packed between hydro-philic layers at x ∼ 0.

2,6-Bis(2-chloro-phen-yl)-4-oxo-3,5-diphenyl-heptane-1,1,7,7-tetra-carbo-nitrile.

In the title compound, C(35)H(24)Cl(2)N(4)O, the phenyl rings are oriented almost parallel to each other, making a dihedral angle of 0.6 (2)°, whereas the chloro-phenyl rings are oriented at a dihedral angle of 28.3 (1)°. The crystal structure is stabilized through an extensive series of C-H⋯N, C-H⋯O and C-H⋯Cl inter-actions. One of the C-H⋯N inter-actions generates an R(2) (2)(12) ring motif around a crystallographic inversion centre. C(5), C(10) and C(12) chain motifs are observed in the unit cell through C-H⋯N and C-H⋯Cl inter-actions. During the structure analysis, it was observed that the unit cell contains large accessible voids, which host disordered solvent mol-ecules. This affects the diffraction pattern, mostly at low scattering angles and was corrected with the SQUEEZE program [Spek, A. L. (2009 ▶). Acta Cryst. D65, 148-155].

2-Nitro-anilinium bromide.

The title compound, C(6)H(7)N(2)O(2) (+)·Br(-), is isomorphous with 2-nitro-anilinium chloride and contains an characteristic intra-molecular N-H⋯O hydrogen bond, forming an S(6) motif. Inter-molecular N-H⋯Br hydrogen bonds occur in the crystal structure. Two zigzag chains of C(2) (1)(4) motifs extend along the b-axis direction. These primary chain motifs inter-sect like a double helix structure, leading to R(6) (3)(12) ring motifs, which are arranged in tandem along the b axis. Hence, hydro-philic layers are generated at z = 1/4 and 3/4, which are sandwiched between alternate hydro-phobic layers across z = 0 and 1/2.

(E)-3-Phenyl-3-(3-phenyl-1H-1-pyrazol-yl)-2-propenal.

In the title compound C(18)H(14)N(2)O, the pendant rings make dihedral angles of 66.1 (1)° and 13.9 (1) with the central ring. In the crystal, two mol-ecules form a cyclic centrosymmetric R(2) (2)(22) dimer through pairs of C-H⋯O bonds. These dimers are further connected into zigzag chains extending along the b axis through C-H⋯π and C-H⋯O inter-actions.

2-Amino-6-(2,4-dichloro-phen-yl)-4-oxo-3,5-diphenyl-cyclo-hex-2-enecarbonitrile.

In the title compound, C(25)H(18)Cl(2)N(2)O, the cyclo-hexene ring has a sofa conformation. All the substituents in the cyclo-hexene ring, except the cyano group (which is axial) occupy equatorial positions. The crystal structure is stabilized through N-H⋯O hydrogen bonds, forming a chain extending along the b axis and through C-H⋯N and C-H⋯Cl inter-actions. It is remarkable that only one of the amino H atoms is involved in hydrogen bonding.

(E)-3-(4-Chloro-phen-yl)-3-[3-(4-chloro-phen-yl)-1H-pyrazol-1-yl]prop-2-enal.

In the title compound, C(18)H(12)Cl(2)N(2)O, the pyrazole ring is almost planar [r.m.s. deviation = 0.002 Å] while the two chloro-phenyl rings are twisted out from the plane of the pyrazole ring, making dihedral angles of 5.3 (1) and 65.34 (4)°. In the crystal, centrosymmetric R(2) (2)(24) dimers are formed about crystallographic inversion centres through a pair of C-H⋯Cl inter-actions. These dimers are further linked through a C-H⋯O hydrogen bond, forming a C(8) chain extending along the a axis. C-H⋯π inter-actions are also observed.

1,5-Dimethyl-3-oxo-2-phenyl-2,3-di-hy-dro-1H-pyrazol-4-aminium 2-hydroxy-benzoate.

In the title salt, C(11)H(14)N(3)O(+)·C(7)H(5)O(3) (-), the phenyl ring of the cation is oriented at an angle of 67.0 (1)° with respect to the five-membered pyrazolone ring. The carboxyl-ate plane of the anion is twisted out from the plane of the aromatic ring at an angle of 13.7 (3)°. In the crystal, the cations form hydrogen-bonded dimers with an R(2) (2)(10) ring motif. The salicylate anion has an intra-molecular O-H⋯O hydrogen bond.

2-Carboxy-anilinium bromide monohydrate.

The title compound, C(7)H(8)NO(2) (+)·Br(-)·H(2)O, is isomorphous with 2-carboxy-anilinium chloride monohydrate and contains an intra-molecular N-H⋯O hydrogen bond, forming an S(6) motif. The main inter-molecular inter-actions are of the N-H⋯O/Br and O-H⋯O/Br types. Hydrogen-bonding dimers are formed via the carboxyl groups and the uncoordinated water mol-ecule, with centrosymmetric R(4) (4)(12) ring motifs, in tandem with centrosymmetric R(8) (4)(16) ring motifs formed by the cations and bromide anions. The hydrogen-bonded ring motifs inter-sect, forming chains with graph-set motif C(4) (3)(10) extending along the a axis. These form a two-dimensional hydrogen-bonded network in (101) which is extended along [010] through N-H⋯Br hydrogen bonds. Hydro-philic layers are generated at z = 0 and 1/2 which are sandwiched between alternate hydro-phobic layers across z = 1/4 and 3/4.

1'-Methyl-4'-(1-naphth-yl)-3''-(1-naphthyl-methyl-ene)acenaphthene-1-spiro-2'-pyrrolidine-3'-spiro-1''-cyclo-hexane-2,2''-dione.

In the title compound, C(42)H(33)NO(2), the six-membered cyclo-hexa-none ring adopts a slightly distorted chair conformation and the five-membered pyrrolidine ring is in an envelope conformation. The mol-ecular structure features four intra-molecular C-H⋯O inter-actions and an intra-molecular C-H⋯π inter-action. Furthermore, the crystal packing is stabilized by an inter-molecular C-H⋯O and three inter-molecular C-H⋯π inter-actions.