scholarly journals An Unusual Cu(II) Mediated C–N Single Bond Cleavage of Pentacoordinating N4S Ligands: Control of Copper Coordination Geometry by Modified Ligand Structure

2019 ◽  
Vol 31 (11) ◽  
pp. 2653-2662
Author(s):  
Dipesh Ghosh
Keyword(s):  
Bond Cleavage ◽  
Alkoxy Group ◽  
Spectroscopic Techniques ◽  
Coordination Geometry ◽  
Ligand Structure ◽  
Cleavage Process ◽  
Square Planar ◽  
Copper Coordination ◽  
Elemental Analyses ◽  
Uv Visible

Complexation of copper(II) with penta-coordinated N4S ligands in alcohols proceeded through unusual reaction paths involving C-N bond cleavage process. The products are square planar compound with a modified ligand structure that includes an alkoxy group provided by the solvent. The complexes are characterized by single crystal XRD, elemental analyses, IR, UV-visible and EPR spectroscopic techniques. Cyclic voltammetry shows Cu(II)/Cu(I) reduction becomes more difficult with the increase in donor strength of alkoxy group.

scholarly journals Preparation Characterization and Antibacterial Studies of Chelates of Schiff Base Derived from4-Aminoantipyrine, Furfural ando-phenylenediamine

2011 ◽  
Vol 8 (3) ◽  
pp. 1408-1416 ◽  
Author(s):  
M. S. Suresh ◽  
V. Prakash
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Free Ligand ◽  
Structural Features ◽  
Screening Tests ◽  
Planar Geometry ◽  
Square Planar ◽  
Elemental Analyses ◽  
Uv Visible ◽  
The Comparative Study

A new series of transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from the Schiff base ligand derived from 4-aminoantipyrine, furfural ando-phenylenediamine. The structural features were derived from their elemental analyses, infrared, UV-visible spectroscopy, NMR spectroscopy, thermal gravimetric analyses, ESR spectral analyses and conductivity measurements. The data of the complexes suggested square planar geometry for the metals with primary valency two. Antimicrobial screening tests were performed against bacteria. The comparative study of the MIC values of the Schiff base and its metal complexes indicate that the metal complexes exhibit greater antibacterial activity than the free ligand.

New Dinuclear Transition Metal Complexes with the [M2(μ-dhbq)]n+ Core and 2-(2′-Pyridyl)quinoxaline (L) as a Terminal Ligand: Preparation and Characterization (dhbq2-= the Dianion of 2,5-Dihydroxy -1,4- benzoquinone; M = AgI, MnII, CoII, NiII, CuII, RuII, PdII, FeIII, RhIII; n = 0, 2, 4)

2001 ◽  
Vol 56 (4-5) ◽  
pp. 394-402 ◽  
Author(s):  
Sahar I. Mostafa ◽  
Spyros P. Perlepes ◽  
Nick Hadjiliadis
Keyword(s):  
Solid State ◽  
Nitrogen Atom ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Spectroscopic Techniques ◽  
Pyridyl Nitrogen ◽  
Terminal Ligand ◽  
Square Planar ◽  
Elemental Analyses ◽  
Bidentate Chelate

Abstract Synthetic procedures are described that allow access to the new complexes [Mn2(dhbq)L2(H2O)4 (1), [Fe2(dhbq)L2(H2O)4](NO3)4 · 6H2O (2), [Co2(dhbq)Cl2L2(H2O)2] (3), [Ni2(dhbq)Cl2L2(H2O)2] (4), [Cu2(dhbq)Cl2L2(H2O)2] (5), [Ru2(dhbq)L2(H2O)4](ClO4)2 (6), [Rh2(dhbq)Cl2L2(H2O)2]Cl2·2H2O (7), [Pd2(dhbq)L2]Cl2·5H2O (8) and [Ag2(dhbq)L2] (9), where dhbq2- is the dianion of 2,5-dihydroxy-1,4-benzoquinone and L is the biheteroaromatic ligand 2-(2′-pyridyl)quinoxaline. The new complexes were characterized by elemental analyses and by a variety of physical and spectroscopic techniques. Dinuclear structures are assigned for the complexes in the solid state. The two metal ions are bridged by the bischelating dhbq2- ion, while L behaves as a bidentate chelate with the 2′-pyridyl nitrogen and the nearest quinoxaline nitrogen atom as the ligand atoms. The metal ion coordination geometries are octahedral, tetrahedral or square planar.

scholarly journals Synthesis Characterization and Biological Activity Study of New Schiff and Mannich Bases and Some Metal Complexes Derived from Isatin and Dithiooxamide

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Ahlam J. Abdulghani ◽  
Nada M. Abbas
Keyword(s):  
Biological Activity ◽  
Metal Complexes ◽  
Condensation Reaction ◽  
Mannich Bases ◽  
Palladium Complexes ◽  
Molar Conductivity ◽  
Square Planar ◽  
Visible Spectra ◽  
Elemental Analyses ◽  
Uv Visible

Two new Schiff and Mannich bases, namely, 1-Morpholinomethyl-3(1′ -N-dithiooxamide)iminoisatin (LIH) and 1-diphenylaminomethyl-3-1′-N-dithiooxamide)iminoisatin (LIIH), were prepared from condensation reaction of new Schiff base 3-(1′-N-dithiooxamide)iminoisatin (SBH) with morpholine or diphenylamine respectively in presence of formaldehyde . The structures were characterized by IR,1HNMR, mass spectrometry, and CHN analyses. Metal complexes of the two ligands were synthesized, and their structures were characterized by elemental analyses, atomic absorption, IR and UV-visible spectra, molar conductivity, and magnetic moment determination. All complexes showed octahedral geometries except palladium complexes which were square planar. The biological activity of the prepared compounds and some selected metal complexes was tested against three types of bacteria and against cell line of human epidermoid larynx carcinoma (Hep-2).

Benzimidazole Derivatives as Potential Antimicrobial and Antiulcer Agents: A Mini Review

2019 ◽  
Vol 19 (16) ◽  
pp. 1292-1297 ◽  
Author(s):  
Ali Mohd Ganie ◽  
Ayaz Mahmood Dar ◽  
Fairooz Ahmad Khan ◽  
Bashir Ahmad Dar
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
1H Nmr ◽  
13C Nmr ◽  
Benzimidazole Derivatives ◽  
Spectroscopic Techniques ◽  
One Pot ◽  
Biological Screening ◽  
Elemental Analyses ◽  
Characterization Studies

:Here in we report the number of strategies for the synthesis of differently substituted benzimidazole derivatives. The protocols involved in the syntheses of these derivatives were one-pot or multi-component. The characterization studies of these derivatives were carried by using different spectroscopic techniques (1H NMR, 13C NMR and MS) and elemental analyses. The biological screening studies revealed that these benzimidazole derivatives show potential antibacterial as well as antifungal behavior. These benzimidazole derivatives not only depicted potential antiulcer properties but also showed moderate to good anticancer/cytotoxic behavior against different cancer cell lines.

Structure of the complexes of ethylenediphosphinetetraacetic acid in solution

1985 ◽  
Vol 50 (2) ◽  
pp. 445-453 ◽  
Author(s):  
Jana Podlahová ◽  
Josef Šilha ◽  
Jaroslav Podlaha
Keyword(s):  
Metal Ion ◽  
Carboxyl Groups ◽  
Complex Solution ◽  
Square Planar ◽  
Weak Complexes ◽  
Carboxylic Groups ◽  
Uv Visible ◽  
The Stability ◽  
Tetrahedral Complexes ◽  
Free Carboxyl

Ethylenediphosphinetetraacetic acid is bonded to metal ions in aqueous solutions in four ways, depending on the type of metal ion: 1) through an ionic bond of the carboxylic groups to form weak complexes with a metal:ligand ratio of 1 : 1 (Ca(II), Mn(II), Zn(II), Pb(II), La(III)); 2) through type 1) bond with contributions from weak interaction with the phosphorus (Cd(II)); 3) through coordination of the ligand as a monodentate P-donor with the free carboxyl groups with formation of 2 : 1 and 1 : 1 complexes (Cu(I), Ag(I)); 4) through formation of square planar or, for Hg(II), tetrahedral complexes with a ratio of 1 : 2 with the ligand as a bidentate PP-donor with the free carboxyl groups (Fe(II), Co(II), Ni(II), Pd(II), Pt(II)). On acidification of the complex solution, the first two protons are bonded to the carboxyl groups. The behaviour during further protonation depends on the type of complex: in complexes of types 1) and 2) phosphorus is protonated and the complex dissociates; in complexes of types 3) and 4) the free carboxyl groups are protonated and the phosphorus-metal bond remains intact. The results are based on correlation of the stability constants, UV-visible, infrared, 1H and 31P NMR spectra and magnetic susceptibilities of the complexes in aqueous solution.

scholarly journals Synthesis, characterization, and pharmacological evaluation of thiourea derivatives

2020 ◽  
Vol 18 (1) ◽  
pp. 764-777
Author(s):  
Sumaira Naz ◽  
Muhammad Zahoor ◽  
Muhammad Naveed Umar ◽  
Saad Alghamdi ◽  
Muhammad Umar Khayam Sahibzada ◽  
...  
Keyword(s):  
Spectroscopic Techniques ◽  
Organosulfur Compounds ◽  
Bacterial Strains ◽  
Thiourea Derivatives ◽  
Toxicological Effects ◽  
Pharmaceutical Industries ◽  
Uv Visible ◽  
Hematological And Biochemical Parameters

AbstractThioureas and their derivatives are organosulfur compounds having applications in numerous fields such as organic synthesis and pharmaceutical industries. Symmetric thiourea derivatives were synthesized by the reaction of various anilines with CS2. The synthesized compounds were characterized using the UV-visible and nuclear magnetic resonance (NMR) spectroscopic techniques. The compounds were screened for in vitro inhibition of α-amylase, α-glucosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes and for their antibacterial and antioxidant potentials. These compounds were fed to Swiss male albino mice to evaluate their toxicological effects and potential to inhibit glucose-6-phosphatase (G6Pase) inhibition. The antibacterial studies revealed that compound 4 was more active against the selected bacterial strains. Compound 1 was more active against 2,2-diphenyl-1-picrylhydrazyl and 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals, AChE, BuChE, and α-glucosidase. Compound 2 was more potent against α-amylase and G6Pase. Toxicity studies showed that compound 4 is safe as it exerted no toxic effect on any of the hematological and biochemical parameters or on liver histology of the experimental animals at any studied dose rate. The synthesized compounds showed promising antibacterial and antioxidant potential and were very active (both in vitro and in vivo) against G6Pase and moderately active against the other selected enzymes used in this study.

scholarly journals Synthesis, Characterization, and Non-Covalent Interactions of Palladium(II)-Amino Acid Complexes

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4331
Author(s):  
David B. Hobart ◽  
Michael A. G. Berg ◽  
Hannah M. Rogers ◽  
Joseph S. Merola
Keyword(s):  
Amino Acid ◽  
High Resolution Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Amino Acid Complexes ◽  
Acetone Water ◽  
Square Planar ◽  
Non Covalent Interactions ◽  
Covalent Interactions

The reaction of palladium(II) acetate with acyclic amino acids in acetone/water yields square planar bis-chelated palladium amino acid complexes that exhibit interesting non-covalent interactions. In all cases, complexes were examined by multiple spectroscopic techniques, especially HRMS (high resolution mass spectrometry), IR (infrared spectroscopy), and 1H NMR (nuclear magnetic resonance) spectroscopy. In some cases, suitable crystals for single crystal X-ray diffraction were able to be grown and the molecular structure was obtained. The molecular geometries of the products are discussed. Except for the alanine complex, all complexes incorporate water molecules into the extended lattice and exhibit N-H···O and/or O···(HOH)···O hydrogen bonding interactions. The non-covalent interactions are discussed in terms of the extended lattice structures exhibited by the structures.

Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2n(n= −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)

2015 ◽  
Vol 22 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Weiwei Gu ◽  
Hongxin Wang ◽  
Kun Wang
Keyword(s):  
Fine Structure ◽  
Multiple Scattering ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Square Planar ◽  
Square Planar Complexes ◽  
Uv Visible ◽  
Edge Features ◽  
X Ray Absorption

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.

Effects of Metal Coordination Geometry on Stabilization of Human Telomeric Quadruplex DNA by Square-Planar and Square-Pyramidal Metal Complexes

2008 ◽  
Vol 47 (24) ◽  
pp. 11910-11919 ◽  
Author(s):  
Anna Arola-Arnal ◽  
Jordi Benet-Buchholz ◽  
Stephen Neidle ◽  
Ramón Vilar
Keyword(s):  
Metal Complexes ◽  
Metal Coordination ◽  
Coordination Geometry ◽  
Quadruplex Dna ◽  
Square Planar

scholarly journals Syntheses and characterisation of chloro(h3-allyl) dicarbonylmolybdenum(II) complexes of chiral and achiral ditertiaryphosphines

2012 ◽  
Vol 10 (1) ◽  
pp. 165-171
Author(s):  
Joe Jesu Raj ◽  
Devendra Pathak ◽  
Pramesh Kapoor
Keyword(s):  
General Formula ◽  
Force Constant ◽  
Spectroscopic Techniques ◽  
Multinuclear Nmr ◽  
Precursor Complex ◽  
Elemental Analyses ◽  
Secular Equations

AbstractA series of the complexes of the general formula [ClMo(CO)2(η 3-C3H5)(P-P)], [where (P-P) = (m-CH3C6H4)2P(CH2)2PPh2 (m-t-dppe); cis-Ph2PCH=CHPPh2 (cis-diphos); Ph2PCH2CH2AsPh2 (arsaphos); Ph2P(CH2)4PPh2 (dppb); (±)-1,2-C6H4(PMePh)2 (rac-diphos); (2R,3R)Ph2PC*H(Me)C*H(Me)PPh2 (+)-chiraphos; (R,R)-Me2C(O)2{C*HCH2PPh2}2 (-)-diop] were synthesised by the reaction of the precursor complex [ClMo(CO)2(η 3-C3H5)(CH3CN)2] with the corresponding ditertiary phosphine in acetone. The complexes were isolated as yellow to orange air-stable solids and characterised by elemental analyses, FTIR and multinuclear NMR [1H, 31P{1H}] spectroscopic techniques. The carbonyl force constant values were calculated by Cotton and Kraihanzel approximate secular equations using ν C≡O stretching frequencies observed in the FTIR and these were found to be 14.30–14.59 mdyne 0-A−1 and 0.23–0.70 mdyne Å−1 for K1 and Ki respectively. Spectroscopic evidences have confirmed cis-octahedral structures for the synthesized complexes.

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