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Recent updates on the synthesis of CF3-containing spirocyclic-oxindoles by employing N-2,2,2-trifluoroethylisatin ketimines are described in this review article.

7,7-Bis(1-cyclopropylcarbonylpiperazino)-8,8-dicyanoquinodimethane, a novel thermally stable fluorophore manifested PCE of 2.26%; ∼10 folds improvement than the plain standalone device, finding its suitability in flexible optoelectronic applications.

Two discrete manganese(III) coordination compounds, [Mn(L)(OCN)]2 (1) and [Mn(L′)(H2O)2][dnba]·DMF·H2O (2) bearing in situ generated Schiff base ligands H2L [H2L = N,N′-o-phenylenebis(salicylaldimine)] or H2L′ [H2L′ = N,N′-bis(salicylidene)ethylenediamine], were easily prepared by treating Mn(CH3COO)2·4H2O with salicylaldehyde and o-phenylenediamine (for 1) or ethylenediamine (for 2), and in the presence of supporting cyanate ligands or 3,5-dinitrobenzoate (dnba) counter anions, respectively. The obtained products were isolated as air-stable crystalline solids and were fully characterized by spectroscopic methods, single-crystal X-ray diffraction, topological analysis, as well as theoretical methods. The X-ray diffraction of the compound 1 reveals that the structure is dimeric with phenolic oxygen atom acting as bridge between two symmetrically equivalent Mn(III) atoms. The structure of 2 contains mononuclear cationic [Mn(L′)(H2O)2] units along with a 3,5-dinitrobenzoate anion and crystallization DMF molecule. Structural analysis indicates a distorted octahedral geometry for both complexes. Intermolecular hydrogen bonding and π–π stacking interactions are present in the lattice and play an important role in cohesion of the structures. Topological analysis of the compound 2 reveals a binodal 3,4-connected underlying 2D net with the 3,4L13 topology. Noncovalent interactions were investigated in terms of energies and geometries using theoretical calculations. Fluorescence and antibacterial properties of 1 and 2 were also investigated and discussed.

Co-crystallization experiments conducted between ortho-phenylenediamine (OPDA) and five substituted aromatic acids (phthalic acid, salicylic acid, 4-hydroxybenzoic acid, 4-nitrobenzoic acid and 3,5-dinitrobenzoic acid) reveal the formation of supramolecular networks constructed from acid–base heterosynthons of ortho-phenylenediammonium cations with respective aromatic anions. All of these coformers are generally regarded as safe (GRAS) molecules. The five reported crystal structures are sustained predominantly by intermolecular N+−H...O−, N—H...O− and N—H...O hydrogen-bonding interactions; in addition intramolecular O—H...O and intermolecular O—H...O, O—H...O− and C—H...O interactions contribute to the formation of various networks. Five 1:1 salts [NH2C6H4NH3]+·[COOHC6H4COO]− (1); [NH2C6H4NH3]+·[OHC6H4COO]− (2); [{NH2C6H4NH2}2·{OHC6H4COOH}2·{NH2C6H4NH3}+ 2·{OHC6H4COO}− 2] (OPDPHB) (3); [NH2C6H4NH3]+·[NO2C6H4COO]− (4) and [NH2C6H4NH3]+·[(NO2)2C6H4COO]− (5) were isolated as single crystals by the slow evaporation method and were characterized using spectroscopic and X-ray crystallographic techniques. X-ray diffraction studies confirmed the formation of salts. The pK a difference between the amine and respective acid favours the transfer of a proton from the acid to the amine, which leads to the formation of the anion and the cation. The interactions between these ions resulted in a stable heterosynthon in each case. The asymmetric units of salts (1), (2), (4) and (5) contain one anion and one cation each, but salt (3) consists of two anions, two cations and two neutral species in its asymmetric unit. A polymorph of salt (3) was also isolated from the crystallization of the ground material from liquid-assisted grinding [{NH2C6H4NH2}·{NH2C6H4NH3}+·{OHC6H4COO}−] (OPDPHB 3P). The polymorph crystallized in the monoclinic non-centrosymmetric space group P21. The liquid-assisted grinding experiments using a 1:1 ratio also revealed the formation of the expected salts, except salt (3), where this product matches with polymorph (OPDPHB 3P).

The asymmetric unit of the title mol­ecular salt, consists of half a 4-amino­benzenaminium cation and a half a 5-carb­oxy­penta­noate anion. Each ion lies about an inversion centre, the other half being generated by inversion symmetry. In the crystal, charge-assisted O—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds together lead to the formation of a three-dimensional supra­molecular framework., The asymmetric unit of the title mol­ecular salt (systematic name: 4-amino­anilinium 5-carb­oxy­penta­noate), C6H9N2 +·C6H9O4 −, consists of half a 4-amino­benzenaminium cation (4-ABA) and half a 5-carb­oxy­penta­noate anion (5-CP); the other half of each ion is generated by inversion symmetry. Protonation of p-phenyl­enedi­amine (PPDA) leads to the formation of a 1:1 salt, but scrutiny of the crystal structure reveals that both of the amine groups of PPDA are partially protonated, with a half-occupied H atom. For the 5-CP anion, an H atom is positioned on an inversion center midway between two O atoms of inversion-related 5-CP ions. In the crystal, the 5-CP anions are linked by the O—H⋯O hydrogen bond to form chains propagating along the [1-10] direction. The chains are linked via N—H⋯O and N—H⋯N hydrogen bonds involving the 4-ABA cations, forming a three-dimensional supra­molecular framework. The title salt was also prepared by mechanochemical synthesis using liquid-assisted grinding (LAG). Its PXRD pattern matches that of the simulated pattern of the crystal structure of the title mol­ecular salt.

Six new salts of an API intermediate 2-aminothiazole with different carboxylic acid coformers were synthesized and characterized by IR (Infrared spectroscopy), 1H-NMR, DSC (Differential scanning calorimetry), XRPD (X-ray powder diffraction) and single crystal XRD. The crystal structure of the salts with benzoic acid, 2,3-, 2,4-, 2,5-, 2,6- dihydroxybenzoic acids and 2,4-dinitrobenzoic acid were determined. The thiazole moiety exhibited solvent (polarity) assisted tautomerism in all reported salts and proton transfer was noticed to the ring N of thiazole due to which two point supramolecular synthon N+−H(thiazole)⋯O−(acid), N−H(amine)⋯O−(acid) was observed. The crystal structures were studied with respect to the positional effect of the competing functional groups like hydroxyl (−OH) and nitro (−NO2) as well as their donor and acceptor abilities for hydrogen bonding. The presence of the non-conventional hydrogen bond (C−H⋯O) has been found to play a critical role in the formation of secondary supramolecular architectures.

A novel series of Pd(II) complexes derived from 2-thiophenecarboxaldehyde and 1,8-diaminonaphthalene has been synthesized and characterized by various physico-chemical and spectroscopic techniques viz., elemental analyses, IR, UV–vis, 1 H and 13 C NMR spectroscopy, and ESI-mass spectrometry. The structure of ligand, 2-(2-thienyl)-2,3-dihydro-1H-perimidine has been ascertained on the basis of single crystal X-ray diffraction. All Pd(II) complexes together with the corresponding ligand have been evaluated for their ability to suppress the in vitro growth of microbes, Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Citrobacter sp., Bacillus subtilis and Stenotrophomonas acidaminiphila and results show that Pd(II) complexes have more significant antimicrobial activity than their corresponding ligand. Fluorescence spectroscopic measurements clearly support that both of the Pd(II) complexes show significant DNA binding with calf thymus DNA.

A family of novel platinum group metal complexes containing bidentate chelating 1-pyrimidyl-3-methylimidazolyl bromide ( HL1 · Br ) and 1-pyrimidyl-3-methylimidazolyl-2-thione ( L2 ) ligands has been synthesized. The synthetic protocol for the formation of these complexes differs from one ligand to the other. Treatment of ligand ( HL1 · Br ) with the metal precursors led to the formation of complexes via in situ carbene transfer reactions. The silver–NHC complex ( 1 ) was formed by the reaction of HL1 · Br with silver oxide under light-free conditions. Subsequent addition of appropriate metal precursors to the silver–NHC complex yielded [(η 6 -arene)Ru( L1 )Cl]PF 6 complexes {arene = C 6 H 6 ( 2 ), p - i PrC 6 H 4 Me ( 3 ), C 6 Me 6 ( 4 )} on stirring at room temperature, whereas the complexes [CpRu( L1 )(PPh 3 )]PF 6 {Cp = C 5 H 5 (5), C 9 H 7 ( 6 )} were obtained under reflux conditions. In the case of ligand L2 , stirring of equimolar quantities of metal precursors and the ligand at room temperature yielded [(η 6 -arene)Ru( L2 )Cl]PF 6 {arene = C 6 H 6 (7), p - i PrC 6 H 4 Me ( 8 ), C 6 Me 6 ( 9 )}, and [Cp ∗ M( L2 )Cl]PF 6 {Cp ∗ = C 5 Me 5 , M = Rh ( 10 ), Ir ( 11 )}. All these complexes were characterized by CHN analysis, IR, NMR and mass spectrometry besides confirmation by single crystal X-ray diffraction studies for some representative complexes as their hexafluorophosphate salts [ 3 ]PF 6 , [ 5 ]PF 6 , [ 8 ]PF 6 and [ 10 ]PF 6 .

Department of Chemistry, Nizam College, Osmania University, Basheerbagh, Hyderabad-500 001, India Department of Chemistry, University College of Science, Osmania University, Hyderabad-500 001, India E-mail : dr_saraladevich@yahoo.com Fax : 91-40-23240806 school of Chemistry, University of Hyderabad, Hyderabad-500 001, India Manuscript received 30 August 2011, revised 09 April 2012, accepted 11 April 2012 The structural properties of N' -[(2-hydroxyphenyl)methylidene]acetohydrazide (NHMAH) have been investigated by various spectro-analytical techniques and computational studies. Energies, heat of formation, dipole moment values and Quantitative Structure Activity Relationships (QSAR) properties were computed employing ChemAxon and HyperChem 7.5 tools. The X-ray diffraction studies reveal the presence of both inter- and intramolecular hydrogen bonding in the crystal packing. The crystal system was found to be monoclinic, with P21/cspace group and the unit cell dimensions are : α = 4.5025 Å (6), b = 26.246 Å (3), c = 8.3869 Å (14) and Z = 4. The pKa values are 10.9 and 13.2. Dinuclear copper(ll) complex of NHMAH is characterized by presence of mass peak at 481. The composition of the complex was also determined spectrophotometrically, by Job's method of continuous variation and mole-ratio method in DMFmedium. Both the experiments confirmed 1 : 1 stoichiometry of the metal complex formed.