An-Najah Staff

Two new neutral dimer Cadmium(II) complexes, [Cd2(dmdphphen)2X4] and where X = Cl (complex 1), Br (complex 2), and dmdphphen = 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, were synthesized and characterized by an elemental analysis, UV-Vis, IR, TG/DTA, CV and single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic system with the space group P-1 with unit cell parameters a = 10.1124(8) Å, b = 10.8875(8) Å, c = 11.5730(9) Å, α = 108.323(3)º, β = 107.010(3)º, γ = 91.260(3)º V = 1147.51(15) Å3 and Z = 1. The Cd(II) ions are located in a slightly distorted square-pyramidal geometry. The complexes exhibit a quasi-reversible one electron response at -570 mV vs. Cp2Fe/Cp2Fe+ , which has been assigned Cd(II)/Cd(III) couples. TG/DTA result shows that these complexes are very stable and decomposed through one step reaction. Calcination of Complex 1, revealed the formation of Cubic nanoparticle CdO.

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Aggregated states have been alluded to for many DNA minor groove binders but details of the molecule-on-molecule relationship have either been under-reported or ignored. Here we report our findings from ITC and NMR measurements carried out with AIK-18/51, a compound representative of the thiazotropsin class of DNA minor groove binders. The free aqueous form of AIK-18/51 is compared with that found in its complex with cognate DNA duplex d(CGACTAGTCG)₂. Molecular self-association of AIK-18/51 is consistent with anti-parallel, face-to-face dimer formation, the building block on which the molecule aggregates. This underlying structure is closely allied to the form found in the ligand's DNA complex. NMR chemical shift and diffusion measurements yield a self-association constant K_ass = (61 ± 19) × 10³ M^− 1 for AIK-18/51 that fits with a stepwise self-assembly model and is consistent with ITC data. The deconstructed energetics of this assembly process are reported with respect to a design strategy for ligand/DNA recognition.

Two tetrahedral mononuclear complexes with a general formula [CoX2(dmphen)](1-2) (where dmphen is 2,9-dimethyl 1,10-phenanthroline and 1 (X=Br), 2 (X=NCS)) have been synthesized. These complexes are characterized by elemental analysis, IR, UV-visible, TG/DTA and by X-ray diffraction.The calculated electrostatic potential surface of 2 has shown that the electrostatic potential values
around sulfur atom is anistropically distributed; the potential values along C-S bond is less negative -region of S atom. This agrees with the observed geometricalpthan the corresponding values in the .°arrangement of C-H…S-C hydrogen bonding interactions, the avg. of H…S-C angle is 81
Antimicrobial properties of cobalt (II) complexes was also assessed. Cobalt complexes exhibited significant antibacterial activity against different Gram negative and positive human pathogens. The absorption spectrum of these complexes in acetone was modeled by time-dependent density functional
theory (TD-DFT).

Five trans-[Ru(P-P)₂Cl₂] complexes were prepared by reacting RuCl₂(PPh₃)₃ with P-P ligands {P–P = 3-hexyl-1,3-bis(diphenylphosphino) propane (hdppp) (1); = 1,3-bis(diphenylphosphino)propane (dppp) (2); = 1,2-bis(diphenylphosphino)ethane (dppe) (3); 1.1’-bis(diphenylphosphino)methane (dppm) (4); 1,2-bis(diphenylphosphino)ethylene (depe) (5}. The complexes were characterized by an elemental analysis, IR, ¹H, ¹³C and ³¹P{1H}NMR, FAB-MS and TG/DTA. These Ru(II) complexes showed Ru(III)/Ru(II) quasireversible redox couple. The molecular structures of the complexes 1 and 3 were determined by X-ray crystallography, and their spectroscopic properties were studied. Another polymorph of 3 was reported in literature, the reported polymorph of 3 in this work crystallizes in p-1 space group, whereas, the previously reported polymorph crystallizes in C2/c space group. The two complexes adopt a distorted trans octahedral coordination and ruthenium (II) ions are located on a crystallographic centre of symmetry. Based on the optimized structures, computational investigations were carried out in order to determine the electronic structures of the complexes. The electronic spectra of 1 and 1⁺ in dichloromethane were calculated with the use of time-dependent DFT methods, and the electronic spectra of the transitions were correlated with the molecular orbitals of the complexes.

The novel trans-[Cl2Ru(II)(PPh3)2(3,4-diaminophenyl)(phenyl)methanone] complex was obtained by reacting RuCl2(PPh3)3 with equimolar amounts of (3,4-diaminophenyl)(phenyl)methanone as diamine co-ligand in CH2Cl2. One of the PPh3 ligand was quantitatively exchanged by (3,4-diaminophenyl)(phenyl)methanone, even when excess diamine was added. The trans-RuCl2 desired complex was characterized on the basis of elemental analysis, elemental analysis, FAB-MS, IR, UV-vis, 1H, 13C and 31P{1H}NMR.

The ligands exchange of the ether-phosphine (Ph2PCH2CH2OCH3) on the diamine(ether-phosphine)ruthenium(II) with 1,3-bis(diphenylphosphino)propane as a bidentate chelate ligand successfully occurs to produce diamine[1,3-bis(diphenylphosphino)propane]ruthenium(II) complexes in a good yields under vigorous stirring for one week in an inert atmosphere using dichloromethane as solvent. Several ether-phosphine-RuC12 complexes with different types of diamine have been tested to confirm the substitution method. In order to collect more information about the system 31P{1H} NMR and 13C{1H} NMR as well as FAB- Mass spectroscopy have been investigated in parallel way to control and support the ligands exchange reaction processes.

We have reported the synthesis of a novel salen ligand and its mononuclear Pd–salen complexes derived from 2-{[2-hydroxy-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}propyl)imino]methyl}phenol. The newly synthesized and isolated Pd(II) complexes have been identified and fully characterized by various physico-chemical studies viz., elemental analyses, IR, UV-Vis, 1H, 13C NMR spectroscopy, electron spray ionization mass spectrometry (ESI-MS) and TGA/DTA studies. The molecular structure of the salen ligand has been ascertained by single-crystal XRD and it is coordinated to Pd(II) ion through two nitrogen and two oxygen atoms. The UV-Vis data clearly suggest a square-planar environment around both the Pd(II) ions. The DNA binding studies of the synthesized compounds has been investigated by electron spectroscopy and fluorescence measurements. The results suggest that Pd(II) complexes bind to DNA strongly as compared to the free ligand. The free salen ligand and its Pd(II) complexes have also been tested against human hepatoma cancer cell line (Huh7) and results manifested exceptional anti-proliferative effects of the Pd(II) complexes. The anti-proliferative activity of Pd(II) complexes has been modulated by specific regulatory genes.

An investigation into the potential ruthenium(II) 1-3 complexes of type [RuCl2(P)2(N)2] using triphenylphosphine and 1,3-bis-diphenylphosphinepropane and 3-(triethoxysilyl)propylamine has been carried out at room temperature in dichloromethane under an inert atmosphere. The structural behaviors of the phosphine ligands in the desired complexes during synthesis were monitored by 31P{1H}-NMR. The structure of complexes 1-3 described herein has been deduced from elemental analyses, infrared, FAB-MS and 1H-, 13C- and 31P-NMR spectroscopy. Xerogels X1-X3 were synthesized by simple sol-gel process of complexes 1-3 using tetraethoxysilane as co-condensation agent in methanol/THF/water solution. Due to their lack of solubility, the structures of X1-X3 were determined by solid state 13C-, 29Si- and 31P-NMR spectroscopy, infrared spectroscopy and EXAFS.