Tapati Banerjee

Synthesis and spectroscopic characterisation of cobalt(III) complexes with S-benzyl dithiocarbazate of 5-methyl-3-formyl pyrazole (HMPzSB): X-ray crystal structure of [Co(MPzSB)2]Cl

Abstract The coordination mode of the title ligand, HMPzSB (synthesized for the first time and characterised by elemental analysis, mass, IR and PMR spectral parameters), is reported by solid state isolation and physicochemical identification of cobalt(III) complexes, [Co(MPzSB)2]X (X = Cl, ClO4 and BF4). Electronic spectral features of these diamagnetic CoIII species classify them as six-coordinate distorted octahedral ones. IR spectra (4000-200 cm−1) of HMPzSB and its complexes are indicative of an uninegative tridentate NNS function of the title ligand through the Pyrazolyl (2N) nitrogen, azomethine nitrogen and thiolato sulphur atom. 1H-NMR data (in d6-DMSO at 300 MHz) of the uncomplexed ligand and its CoIII species are commensurate with the tridenticity (NNS) of the deprotonated form of HMPzSB. X-ray crystallographic studies of [Co(MPzSB)2]Cl has authenticated that the geometry of the species is distorted octahedral, as envisaged, with the two deprotonated primary ligand systems (MPzSB−). The CoN (azomethine) and CoN (pyrazolyl) bond lengths are 1.898(4) & 1.954(5) A and 1.903(4) & 1.916(5) A in ligand A & B, respectively where as that of CoS (thiolato) is 2.217(2) and 2.255(2) A in the two ligands. The extended planarity of the dithiocarbazate moiety and the pyrazolyl ring of the primary ligand system are maintained because of the ligation phenomenon to CoIII.

Synthesis and spectroscopic characterization of nickel(II) complexes with 3,5-dimethyl-1-(o-aminophenyl)pyrazole (DApPz): X-ray crystallographic studies of [Ni(DApPz)2(H2O)2]Cl2·H2O and [Ni(DApPz)2(NCS)2]·H2O

Abstract The coordination mode of the title ligand, DApPz (synthesized and characterized by mass, IR and PMR spectral parameters), is reported by solid-state isolation and physico-chemical identification of a host of bis complexes of nickel(II) with different counter-ions. Magnetic and electronic spectral features classify the reported species, [Ni(DApPz) 2 X 2 ]· n H 2 O, as six-coordinate, pseudo-octahedral with appreciable tetragonal distortion. Vibrational spectral data have indicated a neutral bidentate (NN) function of DApPz through the pyrazolyl (tertiary) ring nitrogen and the aminophenyl nitrogen. In most cases, the counter-ion is coordinated to the nickel(II) ion, but in some cases the water molecules complete the octahedron. X-ray crystallographic studies of [Ni(DApPz) 2 (H 2 O) 2 ]Cl 2 ·H 2 O (monoclinic, P 2 1 / n ) and [Ni(DApPz) 2 (NCS) 2 ]·H 2 O (triclinic, P 1) have unambiguously proved the octahedral environment of the nickel(II) ion; the ligand molecules are cis coordinated to the central nickel(II) ion in both cases. A cis configuration of the coordinated water molecules and the counter-ions (NCS) is established on the basis of an O w NiO w angle of 88.3° and an N NCS NiN NCS angle of 94°.

Synthesis, characterisation and crystal structure analysis of bis (pyridine-2-carbaldehyde thiosemicarbazonato) cobalt(III) thio-cyanate monohydrate

The crystal structure of [CoL2](SCN)·H2O (L = pyridine-2-carbaldehyde thiosemicarbazonato) is reported. The structure, along with other physico-chemical studies, establishes that the compound is a low spin CoIII complex. This resolves confusion arising out of an e

Synthesis and crystal structures of 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole

Both 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide (AHIC) and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole (ACCI) have been synthesized and crystallized in the monoclinic space group P21/c, Z = 4, with a = 8.420(2), b = 9.759(2), c = 10.583(2) Å, β = 111.80(2)° for AHIC and a = 6.139(1), b = 8.522(2), c = 15.156(3) Å, β = 96.71(2)° for ACCI. Differences in the molecular geometries of the two compounds are attributed to the differences in the substituents at the 1- and 4-positions of the imidazole ring. The molecular conformation of AHIC is stabilized by intramolecular hydrogen bonding between the 5-amino and the vicinal carboxamide moiety, resulting in an extended planar structural pattern. The presence of the cyano group in the 4-position of ACCI prevents the formation of such an intramolecular hydrogen bond. Both the crystal structures are stabilized by networks of intermolecular hydrogen bonds.

X-Ray crystal structure of bis-(p-nitroacetophenone-4,6-dimethyl-2-pyrimidyl hydrazone) copper(i) perchlorate

Abstract The title copper(I) complex of a substituted pyrimidyl hydrazone has been synthesized and characterized by X-ray diffraction. The structure has been shown to contain one central Cu atom bonded to four N atoms in a tetrahedral geometry with two hydrazinic N atoms and two pyrimidyl ring N atoms. The structure also proves that the pyrimidine ring and the phenyl ring of the acetophenone moiety are linked by an azomethine linkage. Copyright

Crystal and molecular structure of 4-(N,N-dimethylamino) benzaldehyde thiosemicarbazone

Abstract4-(N,N-Dimethylamino)benzaldehyde thiosemicarbazone, C10H14N4S, has been prepared. The crystal structure has been determined from X-ray diffractometer data byMultan 78. The crystals are triclinic:P¯1,a=8.532(1),b=9.391(1),c=15.592(4) Å,α=73.81(2),β=79.59(2), γ=82.85(2)°,Z=4, finalR=0.033 for 2198 observed reflections. Atomic charge densities have been calculated by the CNDO/2 method. The S and hydrazinic N atoms in both molecules in the asymmetric unit are in thetrans configuration. The crystal structure is stabilized by N-H⋯S hydrogen bonds. The net negative charge on the hydrazinic N atom, calculated by the CNDO/2 method, is decreased as compared to those in some 4-phenylthiosemicarbazide derivatives.

5-Amino-1-[2-(diethylamino)ethyl]-1H-imidazole-4-carboxamide

Intramolecular hydrogen bonds influence the molecular conformation of the title compound, C 10 H 19 N 5 O, resulting in an extended planar hydrogen-bonded heterocyclic ring structure. The bulky diethylaminoethyl group adopts a butterfly conformation. The stabilization of the crystal structure is supported by an extensive network of intermolecular hydrogen bonds.

5-Amino-1-benzyl-4-cyano-3-methylimidazolium toluene-p-sulfonate

The title compound, C12H13N4+·C7H7O3S−, contains an imidazolium cation and a toluene-p-sulfonate anion in the asymmetric unit. Hydrogen-bonded dimers are formed between the cyano and amino groups of inversion-related imidazolium cations.

X-ray elucidation of 17α-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17β-ol

Synthetic pregnen steroid 17α-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17β-ol crystallizes in the orthorhombic space group P212121, with a = 6.601(4), b = 10.530(4), c = 26.177(9) Å, and Z = 4. The structure was solved from Enraf Nonius CAD4 diffractometer data by direct methods and refined to R = 0.0399 for 2041 observed reflections (I > 2σ(I)). The molecule contains five rings of which rings A, B, and C are cyclohexene; ring D is cyclopentene; and ring E is heterocyclic cyclopentene. Ring A acquires the conformation of a half-chair; ring B tends toward a half-chair conformation with a bias toward a chair conformation that contains a β hydrogen at C8 and an α hydrogen at C9. Ring C acquires a near chair conformation with an α hydrogen at C14. Ring D is a 13β, 14α-half chair, and ring E is a O3α-envelope. Both the ring junctions A/B and A/E are quasi-trans, whereas the ring junctions B/C and C/D are both trans. The molecule as a whole is slightly convex toward the β-side, with an angle of 16.7(2)° between the C10–C19 and C13–C18 vectors. Structural association is due to hydrogen bonding and stacking interactions.

Synthesis and crystal structure of (5-amino-4-carboxamidoimidazol-1-yl) acetamide, a possible PDE inhibitor

The crystal structure of 2-(5-amino-4-carboxamidoimidazol-1-yl)acetamide has been determined from X-ray diffractometric data, and refined to anR-value of 0.057 with 1179 observed reflections. Intramolecular hydrogen bonding between the 5-amino group and the vicinal carboxamide moiety stabilizes the molecular conformation and forms an extended planar structural pattern.