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1.  One Step Synthesis of NiO Nanoparticles via Solid-State Thermal Decomposition at Low-Temperature of Novel Aqua(2,9-dimethyl-1,10-phenanthroline)NiCl2 Complex 
[NiCl2(C14H12N2)(H2O)] complex has been synthesized from nickel chloride hexahydrate (NiCl2·6H2O) and 2,9-dimethyl-1,10-phenanthroline (dmphen) as N,N-bidentate ligand. The synthesized complex was characterized by elemental analysis, infrared (IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and differential thermal/thermogravimetric analysis (TG/DTA). The complex was further confirmed by single crystal X-ray diffraction (XRD) as triclinic with space group P-1. The desired complex, subjected to thermal decomposition at low temperature of 400 ºC in an open atmosphere, revealed a novel and facile synthesis of pure NiO nanoparticles with uniform spherical particle; the structure of the NiO nanoparticles product was elucidated on the basis of Fourier transform infrared (FT-IR), UV-vis spectroscopy, TG/DTA, XRD, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDXS) and transmission electron microscopy (TEM).
PMCID: PMC3876087  PMID: 24351867
nickel(II) complex; thermal decomposition; 2,9-dimethyl-1,10-phenanthroline; nanoparticles
2.  N′-[(E)-2-Chloro­benzyl­idene]thio­phene-2-carbohydrazide 
There are two independent mol­ecules in the asymmetric unit of the title compound, C12H9ClN2OS, a Schiff base derived from hydrazide, in which the dihedral angles between the thio­phene and benzene rings are 3.6 (3) and 7.3 (3)°. In the crystal, the two independent mol­ecules are arranged about an approximate non-crystallographic inversion center and are connected by two N—H⋯O hydrogen bonds. Weak C—H⋯Cl contacts are also present. Conversely, there are neither significant aromatic stacking inter­actions nor contacts involving S atoms.
PMCID: PMC3884466  PMID: 24427070
3.  4-Chloro­butyl 7-chloro-1-cyclo­propyl-4-(1,3-diethyl-4,6-dioxo-2-sulfanyl­idene-1,3-diazinan-5-yl­idene)-6-fluoro-1,4-di­hydro­quinoline-3-carboxyl­ate 
The title compound, C25H26Cl2FN3O4S, contains two bio-active moieties (thio­barbituric acid and fluoro­quinolone). In the crystal, mol­ecules are linked via C—H⋯O and C—H⋯F hydrogen bonds, forming two-dimensional slab-like networks lying parallel to the bc plane. The benzene ring substituted by F and Cl atoms and the 4-chloro­butyl group seem to be partly disordered, however attempts to model the disorder were unsuccessful.
PMCID: PMC3793705  PMID: 24109292
4.  rac-(E,E)-N,N′-Bis(2-chloro­benzyl­idene)cyclo­hexane-1,2-di­amine 
In the title racemic Schiff base ligand, C20H20Cl2N2, which was prepared by the condensation of 2-chloro­benzaldehyde and cyclo­hexane-1,2-di­amine, the cyclo­hexane ring adopts a chair conformation and the dihedral angle between the aromatic rings of the 2-chloro­phenyl substituent groups is 62.52 (8)°. In the structure, there are two short intra­molecular methine C—H⋯Cl inter­actions [C⋯Cl = 3.066 (2) and 3.076 (3) Å], and in the crystal there are also weak inter­molecular aromatic C—H⋯Cl [3.464 (3), 3.553 (3) and 3.600 (3) Å] and Cl⋯Cl [3.557 (3) and 3.891 (3) Å] contacts.
PMCID: PMC3770357  PMID: 24046642
5.  2-Phen­oxy­ethyl benzoate 
In the title compound, C15H14O3, the dihedral angle between the benzene rings is 75.85 (7)°. In the crystal, centrosymmetrically related mol­ecules are weakly associated through pairs of inter­actions between a benzene ring and an O atom of the ester group [ring centroid⋯O = 3.952 (7) Å], and through pairs of inter­actions between the other benzene ring and an O atom of the phen­oxy group [ring centroid⋯O = 3.912 (7) Å], giving chains extending along [110].
PMCID: PMC3648312  PMID: 23723932
6.  2,2-Bis(pyridin-2-yl)-1,3-diazinane 
In the title compound, C14H16N4, the six-membered hexa­hydro­pyrimidine ring adopts a chair conformation. In the crystal, one of the two pyrimidine N atoms engages in N—H⋯N hydrogen bonding with one of the pyridine N atoms, generating a helical chain running along the c axis. The helical pitch is the length of the c axis.
PMCID: PMC3629617  PMID: 23634104
7.  Dichlorido(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)mercury(II) 
The title compound, [HgCl2(C14H12N2)], consists of one 2,9-dimethyl-1,10-phenanthroline (dmphen) ligand chelating the HgII ion and two chloride ligands coordinating to the HgII ion, forming a distorted tetra­hedral environment. The dmphen ligand is nearly planar (r.m.s. deviation = 0.0225 Å). The dihedral angle between the normal to the plane defined by the HgII atom and the two Cl atoms and the normal to the plane of the dmphen ring is 81.8 (1)°.
PMCID: PMC3569203  PMID: 23424405
8.  Bis(2,4-dimethyl­pyridinium) tetra­bromido­mercurate(II) 
The asymmetric unit of the title compound, (C7H10N)2[HgBr4], consists of one cation and one half-anion, bis­ected by a twofold rotation axis passing through the metal atom. The anion exhibits a distorted tetra­hedral arrangement about the HgII atom. In the crystal, the cations and anions are linked by N—H⋯Br hydrogen-bonding inter­actions along [010]. Cation–cation π–π stacking and Br⋯Br inter­molecular inter­actions are absent.
PMCID: PMC3588751  PMID: 23468716
9.  Bis{(E)-3-[(2-hy­droxy­benzyl­idene)amino]­prop­yl}ammonium chloride 
The title salt, C20H26N3O2 +·Cl−, lies across a twofold crystallographic axis with the central N atom of the cation and the chloride anion sitting on this axis, Z′ = 0.5. There is an intra­molecular hydrogen bond between the hy­droxy H atom and the imino N atom. The chloride anion and the cation are connected into chains along the a axis by an N—H⋯Cl hydrogen bond. In the crystal, the chains are linked via C—H⋯Cl interactions forming two-dimensional networks lying parallel to (101).
PMCID: PMC3588923  PMID: 23476159
10.  Bis(2,4,6-trimethyl­pyridinium) tetra­bromidozincate 
In the title compound, (C8H12N)2[ZnBr4], the coordination geometry of the anion is approximately tetra­hedral. The Zn—Br bond lengths range from 2.3901 (19) to 2.449 (2) Å and the Br—Zn—Br angles range from 107.09 (8) to 112.48 (8)°. In the crystal, each [ZnBr4]2− anion is connected to four cations through two N—H⋯Br and two C—H⋯Br hydrogen bonds, forming two-dimensional ⋯(cation)2⋯anion⋯(cation2)⋯ sheets parallel to the bc plane. Within each sheet, the anions are arranged in stacks with no significant inter-anion Br⋯Br inter­actions [the shortest being > 4.3 Å], while the cations are in chains, with weak π–π stacking inter­actions [centroid–centroid distance = 3.991 Å] between cations inter­acting with the same anion.
PMCID: PMC3515090  PMID: 23284317
11.  3-(Ammonio­meth­yl)pyridinium dibromide 
In the title salt, C6H10N2 2+·2Br−, the non-H atoms of the 3-methyl­pyridinium unit of the cation are almost coplanar (r.m.s. deviation = 0.0052 Å). In the crystal, the dications and Br anions are linked by a combination of six hydrogen bonds, viz. one Npy—H⋯Br, two C—H⋯Br and three H2N–H⋯Br, into supra­molecular layers, parallel to the bc plane, composed of alternating R24(10) and R24(8) loops. Weak π–π inter­actions between cationic rings with centroid–centroid distances of 3.891 (2) Å are also observed.
PMCID: PMC3515173  PMID: 23284400
12.  Redetermination of 2,2′-bipyridine-1,1′-diium dibromide 
In the title mol­ecular salt, C10H10N2 2+·2Br−, the dihedral angle between the aromatic rings is 20.83 (14)° and the N—H groups have a transoid conformaton [N—C—C—N = 158.5 (3)°]. In the crystal, the cations are linked to the anions by two N—H⋯Br and five C—H⋯Br hydrogen bonds, generating corrugated sheets incorporating R 2 1(7), R 4 2(10), R 4 2(11) and two different R 4 2(12) loops. This structure was originally reported by Nakatsu et al. [Acta Cryst (1972), A28, S24], but no atomic coordinates are available.
PMCID: PMC3470387  PMID: 23125800
13.  2,6-Dimethyl­pyridinium bromide 
The asymmetric unit of the title salt, C7H10N+·Br−, comprises two 2,6-dimethyl­pyridinium cations and two bromide anions. One cation and one anion are situated in general positions, while the other cation and the other anion lie on a crystallographic mirror plane parallel to (010). Each pair of ions inter­act via N—H⋯Br and C—H⋯Br hydrogen bonding, generating motifs depending on the cation and anion involved. Thus, the cation and the anion on the mirror plane generate infinite chains along the c axis, while the other ionic pair leads to sheets parallel to the ac plane. In the overall crystal packing, both motifs alternate along the b axis, with a single layer of the chain motif sandwiched between two double layers of the sheet motif. The sheets and chains are further connected via aryl π–π inter­actions [centroid–centroid distances = 3.690 (2) and 3.714 (2) Å], giving a three-dimensional network.
PMCID: PMC3470347  PMID: 23125760
14.  (2,9-Dimethyl-1,10-phenanthroline-κ2 N,N′)bis­(thio­cyanato-κS)mercury(II) 
The asymmetric unit of the title compound, [Hg(SCN)2(C14H12N2)], contains two complex mol­ecules in which the HgII atoms are both four-coordinated in a distorted tetra­hedral configuration by two N atoms from a chelating 2,9-dimethyl-1,10-phenanthroline ligand and by two S atoms from two thio­cyanate anions. The 1,10-phenanthroline ligand is slightly folded for one complex, the dihedral angle between the pyridine planes being 5.3 (1)°. In contrast it is nearly planar [0.5 (1)°] as it complexes with the other HgII atom. The thio­cyanate ligands are virtually linear and the S atom is bonded to HgII with N⋯S—Hg angles ranging from 99.3 (1) to 103.5 (1)°. Despite the presence of six aromatic rings in the asymmetric unit, there are no significant inter­molecular π–π contacts between phenanthroline ligands as the centroid–centroid distance of the closest contact between six-membered rings is 4.11 (1) A°.
PMCID: PMC3470145  PMID: 23125589
15.  2-Amino-5-methyl­pyridinium dibromo­iodate 
In the title salt, C6H9N2 +·Br2I−, the cation is essentially planar (r.m.s. deviation = 0.0062 Å for the non-H atoms) while the anion is almost linear with a Br—I—Br angle of 177.67 (2)°. The crystal packing shows two anions and two cations connected via N—H⋯Br and (pyridine)N—H⋯Br hydrogen-bonding inter­actions, forming centrosymmetric tetra­mers with R44(16) ring motifs. Very weak offset aromatic π–π stacking interactions [centroid-centroid separation = 4.038 (4), slippage = 1.773 Å] also occur.
PMCID: PMC3435817  PMID: 22969663
16.  Bis(2,6-dimethyl­pyridinium) dibromo­iodate bromide 
In the title salt, 2C7H10N+·IBr2 −·Br−, each of the anions, viz. [IBr2]− and Br−, lie on a twofold axis. The IBr2 − anion is almost linear, with a Br—I—Br angle of 178.25 (3)°. The cation is essentially planar (r.m.s. deviation = 0.0067 Å). In the crystal, each Br− anion links two cations via N—H⋯Br⋯H—N hydrogen-bonding inter­actions.
PMCID: PMC3435755  PMID: 22969626
17.  Bis(2,6-diamino-3,5-dibromo­pyridinium) hexa­bromidostannate(IV) 
The asymmetric unit of the title compound, (C5H6Br2N3)2[SnBr6], contains one cation and one half-anion in which the Sn atom is located on a crystallographic centre of inversion and is in a quasi-octa­hedral geometry. The crystal structure is assembled via hydrogen-bonding inter­actions of two kinds, N(pyridine/amine)—H⋯Br—Sn, along with C—Br⋯Br—Sn interactions [3.4925 (19) Å]. The cations are involved in π–π stacking, which adds an extra supra­molecularity as it presents a strong case of offset-face-to-face motifs [centroid–centroid distance = 3.577 (3) Å]. The inter­molecular hydrogen bonds, short Br⋯Br inter­actions and π–π stacking result in the formation of a three-dimensional supra­molecular architecture.
PMCID: PMC2977624  PMID: 21583810
18.  3-Ammonio­pyridinium tetra­bromido­mercurate(II) monohydrate 
The asymmetric unit of the title compound, (C5H8N2)[HgBr4]·H2O, consists of one cation, one anion and one water mol­ecule. The anion exhibits a distorted tetra­hedral arrangement about the Hg atom. The crystal structure contains alternating sheets of cations (in the ac plane) and stacks of anions. Several strong hydrogen-bonding inter­actions (pyN—H⋯Br and C—H⋯Br; py is pyridine), along with O—H⋯Br inter­actions, connect the sheets of cations to the stacks of anions. Cation–cation π–π stacking is also present (C⋯C distances in the range 3.424–3.865 Å). The shortest Br⋯Br distance is 3.9527 (9) Å.
PMCID: PMC2961581  PMID: 21202445
19.  Bis(2-bromo­pyridinium) hexa­bromido­stannate(IV) 
The asymmetric unit of the title compound, (C5H5BrN)2[SnBr6], contains one cation and one half-anion. The [SnBr6]2− anion is located on an inversion center and forms a quasi-regular octa­hedral arrangement. The crystal structure consists of two-dimensional supra­molecular layers assembled via hydrogen-bonding inter­actions of N—H⋯Br—Sn [D⋯A = 3.375 (13)–3.562 (13) Å and D—H⋯A = 127–142°, along with C—Br⋯Br synthons [3.667 (2) and 3.778 (3) Å]. These layers are parallel to the bc plane and built up from anions inter­acting extensively with the six surrounding cations.
PMCID: PMC2961614  PMID: 21202444
20.  Bis­(2-amino-6-methyl­pyridinium) tetra­bromido­cuprate(II) 
In the crystal structure of the title compound, (C6H9N2)2[CuBr4], the geometry around the Cu atom is inter­mediate between tetra­hedral (Td) and square planar (D4h). Each [CuBr4]2− anion is connected non-symmetrically to four surrounding cations through N—H⋯X (pyridine and amine proton) hydrogen bonds, forming chains of the ladder-type running parallel to the crystallographic b axis. These layers are further connected by means of offset face-to-face inter­actions (parallel to the a axis), giving a three-dimensional network. Cation π–π stacking [centroid separations of 3.69 (9) and 3.71 (1) Å] and Br⋯aryl inter­actions [3.72 (2) and 4.04 (6) Å] are present in the crystal structure. There are no inter­molecular Br⋯Br inter­actions.
PMCID: PMC2961314  PMID: 21202225
21.  Bis(2-bromo­pyridinium) hexa­chlorido­stannate(IV) 
The asymmetric unit of the title compound, (C5H5BrN)2[SnCl6], contains one cation and one half-anion. The [SnCl6]2− anion is located on an inversion center and forms a quasi-regular octa­hedral arrangement. Hydrogen-bonding inter­actions of two kinds, viz. N—H⋯Cl—Sn and C—H⋯Cl—Sn, along with Cl⋯Br inter­actions [3.4393 (15) Å], connect the ions in the crystal structure into two-dimensional supra­molecular arrays. These supra­molecular arrays are arranged in layers approximately parallel to (110) built up from anions inter­acting with six symmetry-related surrounding cations.
PMCID: PMC2961104  PMID: 21202188
22.  Bis(2,6-dimethyl­pyridinium) tetra­bromido­cobaltate(II) 
In the crystal structure of the title compound, (C7H10N)2[CoBr4], the [CoBr4]2− anion is connected to two cations through N—H⋯Br and H2C—H⋯Br hydrogen bonds to form two-dimensional cation–anion–cation layers normal to the crystallographic b axis. Inter­actions of the π–π type are absent between cations in the stacks [centroid–centroid separation = 5.01 (5) Å]. Significant inter­molecular Br–aryl inter­actions are present in the structure, especially an unusually short Br–ring centroid inter­action of 3.78 (1) Å. The coordination geometry of the anion is approximately tetrahedral and a twofold rotation axis passes through the Co atom.
PMCID: PMC2960811  PMID: 21201870
23.  3,6-Diacetyl-1,4-diphenyl-1,4-dihydro-1,2,4,5-tetra­zine 
In the title compound, C18H16N4O2, the central six-membered ring has a boat conformation.
PMCID: PMC2960815  PMID: 21201894

Results 1-23 (23)