Temperature and pressure variations of d–d luminescence band maxima of bis(pyridylalkenolato)palladium(ii) complexes with different ligand substituents: opposite-signed trends

2016 ◽  
Vol 45 (15) ◽  
pp. 6574-6581 ◽  
Author(s):  
Stéphanie Poirier ◽  
Lisa Czympiel ◽  
Nicolas Bélanger-Desmarais ◽  
Sanjay Mathur ◽  
Christian Reber
Keyword(s):  
Luminescence Band ◽  
Negative Shift ◽  
Square Planar ◽  
Temperature And Pressure

Ligand substituents R are used to vary the sign of pressure-induced variations of luminescence maxima Emax, leading to a rare negative shift for a square-planar palladium(ii) compound.

Emitting-state properties of square-planar dithiocarbamate complexes of palladium(II) and platinum(II) probed by pressure-dependent luminescence spectroscopy

2009 ◽  
Vol 87 (11) ◽  
pp. 1625-1635 ◽  
Author(s):  
Caroline Genre ◽  
Geneviève Levasseur-Thériault ◽  
Christian Reber
Keyword(s):  
Crystal Structure ◽  
Luminescence Band ◽  
Room Temperature ◽  
External Pressure ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Square Planar ◽  
Temperature And Pressure ◽  
Monodentate Ligands ◽  
Crystalline Complexes Of

Temperature- and pressure-dependent Raman and luminescence spectra of four crystalline complexes of palladium(II) and platinum(II) with chelating diethyldithiocarbamate (EDTC) and pyrrolidine-N-dithiocarbamate (PDTC) ligands are reported. The crystal structure of [Pd(PDTC)2] was resolved at 120 K. Luminescence band maxima are observed at approximately 14 500 cm–1 and 16 000 cm–1 for the palladium(II) and platinum(II) complexes, respectively. Pressure leads to blue shifts of the band maxima by +9 and +13 cm–1/kbar for [Pd(EDTC)2] and [Pd(PDTC)2], and +15 cm–1/kbar for [Pt(EDTC)2]. These spin-forbidden d–d luminescence transitions have lifetimes of approximately 600 µs at temperatures below 20 K. Luminescence intensities at room temperature are low, but they increase significantly with external pressure. The experimental results show that strong increases of luminescence intensities caused by pressure are not limited to complexes with monodentate ligands, a result providing insight on the coordinates with emitting-state distortions responsible for this effect.

Large Pressure-Induced Red Shift of the Luminescence Band Originating from Nonstacked Square-Planar [Pt(SCN)4]2-in a Novel Trimetallic Complex

2006 ◽  
Vol 45 (6) ◽  
pp. 2379-2381 ◽  
Author(s):  
Geneviève Levasseur-Thériault ◽  
Christian Reber ◽  
Christophe Aronica ◽  
Dominique Luneau
Keyword(s):  
Luminescence Band ◽  
Red Shift ◽  
Large Pressure ◽  
Square Planar

Structural Investigation of Si Quantum Dots Grown by CVD on AlN/Si(111) and 3C-SiC/Si(100) Epilayers

2015 ◽  
Vol 821-823 ◽  
pp. 1003-1006
Author(s):  
Roy Dagher ◽  
Rami Khazaka ◽  
Stephane Vézian ◽  
Monique Teissiere ◽  
Adrien Michon ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Confinement ◽  
Luminescence Band ◽  
Structural Investigation ◽  
Wetting Layer ◽  
Fixed Temperature ◽  
Structural Investigations ◽  
Temperature And Pressure ◽  
Si Quantum Dots

Structural investigations of Si quantum dots (QDs) grown by CVD on two different heterostructures: AlN/Si (111) and 3C-SiC/Si (100) are conducted. The Si QDs have been grown using silane as precursor, diluted in hydrogen, at fixed temperature and pressure (830°C - 800mbar). High densities of dots can be obtained (up to 1011 cm-2) with typical heights below 10nm. The kinetic of deposition lets suppose the presence of an initial wetting layer before the dots formation. Different durations are required for nucleating dots on AlN and 3C-SiC. Si QDs on AlN present a luminescence band which can be attributed to quantum confinement.

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

Crystal chemistry of high-Tc superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 1118-1119
Author(s):  
Maryvonne Hervieu
Keyword(s):  
Oxygen Deficiency ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc ◽  
Single Mechanism ◽  
Square Planar ◽  
History Of ◽  
Bismuth Cuprates ◽  
New Compounds

Four years after the discovery of superconductivity at high temperature in the Ba-La-Cu-O system, more than thirty new compounds have been synthesized, which can be classified in six series of copper oxides: La2CuO4 - type oxides, bismuth cuprates, YBa2Cu3O7 family, thallium cuprates, lead cuprates and Nd2CuO4 - type oxides. Despite their quite different specific natures, close relationships allow their structures to be simply described through a single mechanism. The fifth first families can indeed be described as intergrowths of multiple oxygen deficient perovskite slabs with multiple rock salt-type slabs, according to the representation [ACuO3-x]m [AO]n.The n and m values are integer in the parent structures, n varying from 0 to 3 and m from 1 to 4; every member of this large family can thus be symbolized by [m,n]. The oxygen deficient character of the perovskite slabs involves the existence or the co-existence of several types of copper environment: octahedral, pyramidal and square planar.Both mechanisms, oxygen deficiency and intergrowth, are well known to give rise easily to nonstoichiometry phenomena. Numerous and various phenomena have actually been characterized in these cuprates, strongly depending on the thermal history of the samples.

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