scholarly journals Structural characterization of two solvates of a luminescent copper(II) bis(pyridine)-substituted benzimidazole complex

2017 ◽  
Vol 73 (11) ◽  
pp. 1616-1621 ◽  
Author(s):  
David K. Geiger ◽  
Matthew R. DeStefano ◽  
Robert A. Lewis
Keyword(s):  
Absorption Spectrum ◽  
Biological Activity ◽  
Room Temperature ◽  
Bond Distance ◽  
Ligand Field ◽  
Asymmetric Unit ◽  
Square Planar ◽  
Pharmaceutical Uses ◽  
Room Temperature Luminescence

Copper(II) complexes of benzimidazole are known to exhibit biological activity that makes them of interest for chemotherapeutic and other pharmaceutical uses. The complex bis(acetato-κO){5,6-dimethyl-2-(pyridin-2-yl)-1-[(pyridin-2-yl)methyl]-1H-benzimidazole-κ2N2,N3}copper(II), has been prepared. The absorption spectrum has features attributed to intraligand and ligand-field transitions and the complex exhibits ligand-centered room-temperature luminescence in solution. The acetonitrile monosolvate, [Cu(C2H3O2)2(C20H18N4)]·C2H3N (1), and the ethanol hemisolvate, [Cu(C2H3O2)2(C20H18N4)]·0.5C2H6O (2), have been structurally characterized. Compound2has two copper(II) complexes in the asymmetric unit. In both1and2, distorted square-planar N2O2coordination geometries are observed and the Cu—N(Im) bond distance is slightly shorter than the Cu—N(py) bond distance. Intermolecular π–π interactions are found in1and2. A weak C—H...π interaction is observed in1.

Synthesis and Characterization of Palladium(II) Complexes with Substituted Dihydrobenzoimidazoquinazoline Derivatives

2016 ◽  
Vol 15 (2) ◽  
pp. 17-32
Author(s):  
Rita Bhattacharjee
Keyword(s):  
Thermal Analysis ◽  
Biological Activity ◽  
Mass Spectra ◽  
Molar Conductivity ◽  
Synthesis And Characterization ◽  
Planar Geometry ◽  
Conductivity Measurements ◽  
Square Planar

A series of palladium(II) halo complexes of the types[PdX2L2].nH2O {n = 0, X = Cl, L = L4and L6; X = Br, L = L3,L4, L5 and L6; n = 2, X = Cl, L = L3and L7, X = Br, L = L1};Pd2X4L2 {X = Cl, Br, L = L2 and L8} and Pd2X4L3 [X = Cl, L= L1; X = Br, L = L7] were prepared where L is 6-R-5,6-dihydrobenzoimidazo quinazoline (R-Diq; where R =phenyl: L1/furyl: L2/thiophenyl: L3/o- or phydroxyphenyl: L4, L5/o- or p-chlorophenyl: L6,L7/dimethylaminophenyl: L8and characterized byelemental analyses, molar conductivity measurements,TGA, infrared, electronic, NMR and mass spectraltechniques. Based on these studies, monomeric/dimericstructure with a square planar geometry around the metalion was proposed for these complexes. Anti-microbialactivity for some of the synthesized complexes wereinvestigated.Keywords: dihydrobenzoimidazoquinazoline, palladium(II),thermal analysis, mass spectra, biological activity.

Synthesis of Phosphorescent Platinum Complexes with 3-Aryl Pyridazine as Prominent Emitting Materials in Organic Light-Emitting Device

2005 ◽  
Vol 277-279 ◽  
pp. 1006-1010
Author(s):  
Seung Hee Lee ◽  
Won Hee Han ◽  
Hyun Seo Shin ◽  
Sang Jin Lee
Keyword(s):  
Room Temperature ◽  
General Structure ◽  
Platinum Complexes ◽  
Life Time ◽  
Molecular Orbital Calculation ◽  
Ancillary Ligands ◽  
Light Emitting ◽  
Organic Light ◽  
Square Planar

The synthesis and characterization of a series of square planar Pt(II) complexes, which are luminescent at room temperature, are reported. The complexes have the general structure of (C^N)Pt(O^O), where HC^N is 3-phenylpyridazine (ppdz), 3-(4’-biphenyl)pyridazine (4’phppdz), 3-(2’-naphthyl)pyridazine (2’napdz), or 3-(1’-naphthyl)pyridazine (1’napdz), and HO^O is acetylacetone (Hacac). The reaction of K2PtCl4 with HC^N forms the chloro-bridged dimer, (C^N)Pt( µ-Cl)2Pt(C^N), which are cleaved with an ancillary ligand to give the corresponding monomeric (C^N)Pt(O^O) complexes. The emission bands of these complexes are governed by the structure of the cyclometalating ligands, with emission band (lem) ranging from 516 to 645 nm. The two emission bands at (515 and 550 nm) of (ppdz)Pt(acac) complex have 7 and 6 ms of life time which imply those bands are due to phosphorescence decay. The conjugating ring on the pyridazine makes the emission more red shifted which is expected based on molecular orbital calculation. In addition to the alteration of cyclometalating ligands, ancillary ligands also change. These results can be compared with the corresponding Ir(III) complexes.

scholarly journals Crystallographic and structural characterization of heterometalic platinum complexes Part X. Heteropolynuclear pt complexes

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive E. Holloway
Keyword(s):  
Transition Metals ◽  
Structural Characterization ◽  
Bond Distance ◽  
Platinum Complexes ◽  
Square Planar ◽  
The Mean

AbstractThis review covers heteropolynuclear platinum complexes. There are over sixty examples with heterometal atoms as partners including non- transition metals, K, Cs, Mg, Ca, Sr, Tl, Sn, Pb, Zn, Cd, and transition metals: Cu, Ag, Fe, Co, Ni, Rh and Pd. In addition, there are examples for the lanthanides, Eu and Yb. The most common are Ag (x16) and K (x14). The predominant geometries for Pt(II) is square-planar and for Pt(IV) is octahedral. The overall structures are complex. In spite of the wide variety of heterometal atoms partners of platinum, there is “real” Pt-M bonds only with silver, ranging from 2.678 to 2.943(I) Å (ave 2.855 Å). The mean Pt-Pt bond distance is 2.869 Å.

Optical Characterization of the Visible Photoluminescence from Porous Silicon

1991 ◽  
Vol 256 ◽  
Author(s):  
H. D. Fuchs ◽  
M. S. Brandt ◽  
M. Stutzmann ◽  
J. Weber
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Laser Excitation ◽  
Pulsed Laser ◽  
Infrared Transmission ◽  
Visible Photoluminescence ◽  
Etched Silicon ◽  
Transmission Measurements ◽  
Room Temperature Luminescence

ABSTRACTThe visible photoluminescence of electrochemically etched silicon wafers is studied by cw- and pulsed-laser excitation. Raman data and infrared transmission measurements on the same samples prove the presence of oxygen and hydrogen in different bonding configurations in the luminescent layers. Identical optical properties are found for chemically synthesized siloxene (Si6O3H6) and its derivates. We present evidence that the origin of the strong room temperature luminescence in “porous” silicon can be traced to siloxene derivates present in the samples.

scholarly journals The First Metal Complexes of 4,6-diamino-1-hydro-5-hydroxy-pyrimidine-2-thione: Preparation, Physical and Spectroscopic Studies, and Preliminary Antimicrobial Properties

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Sahar I. Mostafa ◽  
Constantina Papatriantafyllopoulou ◽  
Spyros P. Perlepes ◽  
Nick Hadjiliadis
Keyword(s):  
Metal Ion ◽  
Room Temperature ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Spectroscopic Studies ◽  
Ligand Field ◽  
Square Planar ◽  
Elemental Analyses ◽  
Bidentate Chelate

The new complexes[M2O5L2(H2O)2]⋅H2O (M=Mo,1;M=W,2),[RuL2(H2O)2]⋅H2O (3),[ML3]⋅xH2O (M=Rh,x=2,4;M=Ir,x=1,5),[RhL2(PPh3)2](ClO4)⋅2H2O (6),[PdL2]⋅2H2O (7),[PdL(phen)]Cl⋅H2O (8),[Re⁡OL2(PPh3)]Cl (9)and[UO2L2] (10)are reported, where LH is 4,6-diamino-1-hydro-5-hydroxy-pyrimidine-2-thione. The complexes were characterized by elemental analyses, physical techniques (molar conductivity, room-temperature magnetic susceptibility), and spectroscopic (IR, Raman, UV/VIS/ligand field, NMR, mass) methods. The ligandL−is in its thione form and behaves as a bidentate chelate with the deprotonated (hydroxyl) oxygen and the nitrogen of one amino group as donor atoms. Oxobridged dinuclear(1, 2)and various mononuclear(3–10)structures are assigned for the complexes in the solid state. The metal ion coordination geometries are octahedral(1–6, 9, 10)or square planar(7, 8). The free ligand LH and complexes1,4,7, and8were assayed in vitro for antimicrobial activity against two bacterial and two fungal cultures.

scholarly journals Crystal structure of the thermochromic bis(diethylammonium) tetrachloridocuprate(II) complex

2016 ◽  
Vol 72 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Emily P. Aldrich ◽  
Katherine A. Bussey ◽  
Jennifer R. Connell ◽  
Erin F. Reinhart ◽  
Kayode D. Oshin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Complex Salt ◽  
Title Complex ◽  
Asymmetric Unit ◽  
Orthorhombic Space Group ◽  
Coordination Environment ◽  
The Third ◽  
Square Planar ◽  
Deep Green ◽  
Hydrogen Bonded

In the structure of the title complex salt, (Et2NH2)2[CuCl4], the asymmetric unit consists of four unique diethylammonium cations and three unique tetrachloridocuprate anions. Two of the three anions are located with their copper atoms on independent crystallographic twofold axes, while the remaining tetrachloridocuprate is located at a general position of the orthorhombic space groupP21212. Two of the three Cu atoms adopt a distorted square-planar/disphenoidal geometry and the third Cu atom has a regular square-planar coordination environment. The diethylammonium cations form an extensive hydrogen-bonded network through N—H...Cl interactions with the tetrachloridocuprate anions, resulting in a two-dimensional sheet-like hydrogen-bonded network parallel to theabdirection. The complex was observed to undergo a color shift from deep green at room temperature to pale yellow at temperatures above 328 K.

Characterization of Chemically Synthesized Ag2Se Nanowires via Anodic Alumina Membrane as Template

2012 ◽  
Vol 628 ◽  
pp. 21-26 ◽  
Author(s):  
Ranjeet Singh ◽  
S.K. Sharma ◽  
S.K. Chakarvarti
Keyword(s):  
Absorption Spectrum ◽  
Chemical Method ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Anodic Alumina ◽  
Atomic Composition ◽  
Anodic Alumina Membrane ◽  
Orthorhombic Structure ◽  
Alumina Membrane

Highly ordered nano crystallized Ag2Se nanowires of diameter 200 nm have been successfully prepared through direct chemical method using Anodic Alumina Membrane (AAM) as a template; AgNO3 as cation precursor agent and Na2SeSO3 as Se precursor, respectively at room temperature. The qualitative analysis of the EDAX spectrum of nanowires shows that the atomic composition of Ag and Se in synthesized nanowires is close to 2:1 stoichiometry. XRD spectrum confirms orthorhombic structure. UV-Vis absorption spectrum provides estimation of the optical band gap 1.41 eV of nanowires.

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