RESUMO
Dicyanoaurate reacts with the organic acceptor molecule, 1,1'-bis-(2,4-dinitrophenyl)-4,4'-bipyridinium, DNP, to form a supramolecular complex with the general formula {[Au(CN)(2)](2)DNP}·4H(2)O. The complex was characterized by X-ray crystallography, and its photophysical properties were investigated in the solid-state. Although the initial (DNP)Cl(2) compound does not show photoluminescence behavior and the dicyanoaurate shows photoluminescence only in the UV range, the resulting supramolecular complex displays two simultaneous, essentially independent, photoluminescence bands in the visible range originating from individual contributions of the DNP unit and the dicyanoaurate dimers. This unusual simultaneous photoluminescence behavior displayed by both the dicyanoaurate donor units and the redox-active 4,4'-bipyridinium acceptor have lifetimes of 0.5 µs and several hundred µs, respectively.
RESUMO
A series of d(10) dicyanometallate polymeric compounds were studied by electronic spectroscopy and density functional theory (DFT) calculations. In these materials, the negatively charged one-dimensional (1D) polymeric chains are linked together by [M(en)(2)](2+) (M = Cu(II) and Zn(II); en = ethylenediamine). More than innocent building blocks, the [M(en)(2)](2+) units offer a possible synthetic way to modify electronic properties of the materials. Through its low energy d-d excited state, the d(9) copper(II) ions offer deactivation pathways for the normally emissive dicyanometallate polymer. Deactivation was shown to be specific to the excited state energy.
RESUMO
A series of lanthanide-doped nonanuclear yttrium(III) clusters with general formulas (Y(9-x)Ln(x))(acac)(16)(µ(3)-OH)(8)(µ(4)-O)(µ(4)-OH) (Ln = Pr, Eu, Tb, Dy, and Yb) were synthesized. Characterization by single-crystal X-ray diffraction allowed for analysis of relative populations of yttrium (Z = 39) and dopant trivalent lanthanide (Z = 59-70) at every crystallographic metal position. Nonuniform distribution of ions along the three different sites seems to be correlated to the site volume and the ratio of ionic radii. In support, luminescence spectra of europium(III)-doped nonanuclear clusters were measured over a wide range of dopant concentrations. Emission intensities of peaks characteristic of specific sites correlate well with the site population determined through X-ray diffraction.
Assuntos
Elementos da Série dos Lantanídeos/química , Ítrio/química , Cristalografia por Raios X , Európio/química , Luminescência , Modelos Moleculares , Análise EspectralAssuntos
Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/diagnóstico , Atelectasia Pulmonar/diagnóstico , Atelectasia Pulmonar/etiologia , Idoso de 80 Anos ou mais , Broncoscopia , Meios de Contraste , Diagnóstico Diferencial , Humanos , Masculino , Interpretação de Imagem Radiográfica Assistida por Computador , Radiografia TorácicaRESUMO
Copper(i) cyanide exposed to various liquid or vapor-phase amines (L) at ambient temperature produces a variety of visible photoluminescence colors via reversible formation of amine adducts. The adducts show phase matches to authentic (CuCN)L(n), n = 0.75-2.0, produced by heating CuCN with liquid amine.
Assuntos
Aminas/química , Cobre/química , Cianetos/química , Luminescência , Compostos Organometálicos/síntese química , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Compostos Organometálicos/químicaRESUMO
Severe neurological decompression sickness (DCS) has been a rare entity in the U.S. Air Force, including the U-2 community. In over 50 yr of operation, few U-2 pilots reported severe neurological DCS in flight despite the extreme altitudes at which they operate. This article describes a near-fatal case of neurological DCS that occurred during a combat mission. The injury left the pilot with permanent cognitive deficits that correlated with focal lesions present on magnetic resonance imaging of his brain. To our knowledge, the images presented herein are the first to show radiological evidence of brain injury induced by altitude DCS. Though only a single case, the objective and clinical findings in the case pilot are similar to results documented in divers suffering DCS with central nervous system injury and victims of traumatic brain injury. DCS will remain a potentially serious threat to current and future air and space operations.
Assuntos
Medicina Aeroespacial , Aeronaves , Doença da Descompressão/etiologia , Doenças do Sistema Nervoso/etiologia , Encéfalo/patologia , Lesões Encefálicas/diagnóstico , Lesões Encefálicas/etiologia , Doença da Descompressão/complicações , Doença da Descompressão/diagnóstico , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Medicina Militar , Militares , Doenças do Sistema Nervoso/diagnóstico , Recidiva , Estados UnidosRESUMO
A series of Eu(III) and Tb(III) clusters as well as their Y(III) analogues with increasing nuclearities of 5, 8 and 9 have been synthesised using beta-diketonate ligands with decreasing steric hindrance. Their molecular structures have been established from X-ray diffraction on single crystals for most clusters and studied by luminescence and Raman spectroscopy. The Raman spectra have distinctive patterns for each nuclearity in accordance with their crystal structure. The luminescence spectra of the Eu(III) and Tb(III) clusters also show distinctive features.
RESUMO
A series of discrete compounds and supramolecular polymers were synthesized by self-assembly of dithioether building blocks and HAuCl4.3H2O. In complexes 1 {[AuL(1-Me)Cl], where L(1-Me) is bis(methylthio)methane} and 2 {[Au2L(2-Ph)Cl2], where L(2-Ph) is 1,2-bis(phenylthio)ethane}, adjacent units are connected via aurophilic interactions. Complex 1, a one-dimensional (1D) supramolecular polymer, and complex 2, a two-dimensional supramolecular network, both feature nearly linear [Au-Au-](infinity) chains. Complexes 4a, 4b, and 4c, all of which contain 1,3-bis(phenylthio)propane (L(3-Ph)), are polymorphs having the composition [Au2L(3-Ph)Cl2]. Complex 3 {[Au2L(1-Ph)Cl2], where L(1-Ph) is bis(phenylthio)methane}and complexes 4a and 4b consist of nearly identical 1D supramolecular polymers formed through Au-Au interactions. The third polymorph, 4c, is a molecular complex, as it does not have metal-metal interactions. Complex 5 {[Au2L(4-Ph)Cl2], where L(4-Ph) is 1,4-bis(phenylthio)butane} is also molecular. UV-vis spectra showed that the absorption bands of these complexes are allowed ligand-centered transitions between 230 and 260 nm. Complexes 1, 2, and 6 {[AuL(3-Me)Cl], where L(3-Me) is 1,3-bis(methylthio)propane} exhibited solid-state luminescence at 5 K with vibronic progressions and band maxima at approximately 570 nm. It is suggested that complex 6 contains [Au-Au-](infinity) chains.