NOPR Collection:

Synthesis, spectroscopic characterisation, corrosion inhibition studies and dyeing properties of lanthanide(III) complexes of 1-[(3-carboxyethyl-4,5-dimethylthiophen-2-yl)azo]-2-naphthol

2021-04-01T00:00:00Z

Title: Synthesis, spectroscopic characterisation, corrosion inhibition studies and dyeing properties of lanthanide(III) complexes of 1-[(3-carboxyethyl-4,5-dimethylthiophen-2-yl)azo]-2-naphthol Authors: Athira, C J; Sujamol, M S; Sindhu, Y; Mohanan, K Abstract: Ligational behaviour of the heterocyclic ligand obtained by coupling of diazotized 2-amino-3-carboxyethyl-4,5-dimethylthiophene with β-naphthol towards some selected lanthanide(III) ions has been studied. Various spectral and physico-chemical techniques have been used to confirm the coordination sites of the ligand (HTAN) and its lanthanide(III) complexes. It has been observed that these ligands coordinate to the metal ions in a neutral tridentate fashion. Thermal stability of metal chelates and structural stability of the chelating agent has been studied by thermal analysis. As lanthanides and azo dyes are reported as good corrosion inhibitors we have examined the corrosion inhibition activities of HTAN and its metal complexes. Also dyeing properties of the azo dye and some of its selected complexes towards cotton fabrics has been evaluated, as the traditional application field of the synthetic azo dyes still remains in the textile industry. Page(s): 489-498

Synthesis and structure of a mixed ligand copper(II) compound based on a distorted {CuN2O3} square pyramid

2021-04-01T00:00:00Z

Title: Synthesis and structure of a mixed ligand copper(II) compound based on a distorted {CuN2O3} square pyramid Authors: Deshpande, Megha S; Naik, Amrita A; Morajkar, Sudesh M; Srinivasan, Bikshandarkoil R Abstract: The synthesis, spectra, thermal study and crystal structure of a mixed ligand copper(II) compound viz. [Cu(biq)(acac)(NO₃)] 1 (biq = 2,2′-biquinoline, acac = acetylacetonate) are reported. The {CuN₂O₃} coordination sphere is made up of two oxygen atoms of an unique acac ligand, an oxygen of the nitrate group and one N atom of biq ligand which form the basal plane {CuNO₃} of a square pyramid. A second nitrogen atom of the biq ligand occupies the apical position resulting in a distorted square pyramidal {CuN₂O₃} polyhedron. In the crystal structure, each neutral square pyramidal copper(II) species is linked with two symmetry related molecules with the aid of intermolecular C-H^...O hydrogen bonding interactions. A study of fifteen mixed ligand copper(II) acetylacetonates reveals that in this series of compounds, 1 exhibits maximum deviation of the {CuN₂O₃} polyhedron from square pyramidal towards trigonal bipyramidal geometry. Page(s): 499-505

New mono- and polynuclear copper(II) complexes: Structural characterization, quantum chemical calculations and antioxidant superoxide dismutase studies

2021-04-01T00:00:00Z

Title: New mono- and polynuclear copper(II) complexes: Structural characterization, quantum chemical calculations and antioxidant superoxide dismutase studies Authors: Patel, Ram N; Patel, Satish K; Kumhar, D; Patel, Nirmala; Butcher, Raymond J Abstract: Two copper(II) complexes have been synthesized and characterized using elemental and spectral analysis. The molecular structures of both complexes have been confirmed by single crystal X-ray analysis. The stability of the metal centre was examined using cyclic and differential pulse voltammetry in DMSO solution. X-band electron paramagnetic spectra were recorded both in solid and frozen solution to confirm the d⁹ configuration. Frozen solution spectra of complexes have the trend in the spin Hamiltonian parameters g_ǁ > g > 2.0023 and A_ǁ 156 x 10^-4 cm^-1 revealing a d_x²-_y² ground state with tetragonal symmetry for copper(II) ion. Density functional calculations have been performed and results are found to agree with the experimental results. Antibacterial activities of complexes were screened by taking gram-positive and gram-negative bacteria. Further, in vitro antioxidant (superoxide dismutase) properties of 1 and 2 showed considerable activity compared to other SOD mimics. Page(s): 506-518

The potential anticancer activities of platinum(II) complexes with tridentate N'N'N' pincer ligands

2021-04-01T00:00:00Z

Title: The potential anticancer activities of platinum(II) complexes with tridentate N'N'N' pincer ligands Authors: Lasri, Jamal; Aly, Magda M; Eltayeb, Naser E; Alamri, Mona A; Babgi, Bandar A; Hussien, Mostafa A Abstract: Treatment of cis/trans-[PtCl₂(N≡CR)₂] 1 (R = CH₃ (1a), C₂H₅ (1b), C₆H₅ (1c), CH₂C₆H₄(p-CH₃) (1d)) with 1,3-diiminoisoindoline 2 gives access to the corresponding symmetrical (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato) platinum(II) complexes [PtCl{NH=C(R)N=C(C₆H₄)NC=NC(R)=NH}] 3a-d, in good yields (65–77%). The compounds 3a-d have been characterized by IR, ¹H, ¹³C and DEPT-135 NMR spectroscopies, ESI-MS and elemental analyses. GIAO/DFT studies have been performed to confirm the molecular structure of the platinum(II)-pincer 3d by comparing the experimental and theoretical ¹H and ¹³C NMR chemical shifts, and it has shown good correlations between experimental and calculated chemical shifts for proton and carbon with correlation coefficients of 0.9947 and 0.9968, respectively. Molecular electrostatic potential is used to investigate the nucleophilic or electrophilic regions in the molecule 3d. The antimicrobial activities of compounds 3a-d are determined against different bacterial pathogens and yeasts. No toxicity is recorded against Artemia saline as a test organism for 3a-c, while moderate toxicity is found for 3d at 0.62 µM. Comparable antitumor activities are found for 3a-d against human colon HCT116 and human breast (MCF-7) cancer cell lines. The complexes 3a-d have shown good binding affinities to ct-DNA in the range of 6.00´10⁵ to 8.33´10⁵ and the conducted molecular docking studies suggest an intercalation mode of binding with DNA by the isoindole fragment of the ligands. Overall, this class of tridentate ligands have shown good potential in designing platinum(II) complexes with promising biological and anticancer activities. Moreover, the presence of the side chains on the ligands provides great design flexibility by introducing some chemical and/or physical characteristics. Page(s): 519-530