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.

Temperature- and pressure-dependent luminescence spectroscopy on the trans-[ReO2(pyridine)4]+ complex — Analysis of vibronic structure, luminescence energies, and bonding characteristics

2004 ◽  
Vol 82 (6) ◽  
pp. 1083-1091 ◽  
Author(s):  
John K Grey ◽  
Ian S Butler ◽  
Christian Reber
Keyword(s):  
Molecular Structure ◽  
Low Temperature ◽  
Room Temperature ◽  
Complex Analysis ◽  
Variable Pressure ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Vibronic Structure ◽  
Temperature Spectra ◽  
Temperature And Pressure

Resolved vibronic structure in electronic spectra provides a detailed view into how molecular structure changes after absorption or emission of a photon. We report temperature- and pressure-dependent luminescence spectra of trans-[ReO2(pyridine)4]I. Low-temperature spectra reveal long vibronic progressions in the totally symmetric O=Re=O (907 cm–1) and Re-pyridine (211 cm–1) stretching modes, indicating large structural displacements along these normal coordinates. The luminescence band maximum is at ca. 15 500 cm–1. Room-temperature spectra are somewhat less-resolved; however, intervals closely matching the O=Re=O frequency (~870 cm–1) persist at higher temperatures. The variable pressure spectra exhibit distinct changes in the vibronic patterns, and luminescence energies decrease by 16 ± 2 cm–1/kbar (1 bar = 100 kPa). Low-temperature spectra are modeled using two-dimensional potential energy surfaces to represent the initial and final electronic states, from which the quantitative normal coordinate offsets can be determined. We then adapt this model to the room-temperature, pressure-dependent data where it is possible to determine how the offsets and other important spectroscopic parameters vary with the pressure-induced changes of the molecular structure. Key words: trans-[ReO2(pyridine)4]I, low-temperature luminescence spectroscopy, high-pressure luminescence spectroscopy, vibronic structure, emitting state distortions.

Eu3+ Ion Luminescence Spectra from Lanthanide Sesquioxides Exhibiting Three Different Crystal Structures

1992 ◽  
Vol 46 (2) ◽  
pp. 273-276 ◽  
Author(s):  
G. Chen ◽  
R. G. Haire ◽  
J. R. Peterson
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Room Temperature ◽  
Luminescence Spectra ◽  
Spectral Splitting ◽  
The Eu

We have investigated the Eu3+ ion luminescence spectra from different host crystals of the lanthanide sesquioxides exhibiting either the A, B, or C form. The Eu3+ ion luminescence spectra from B-type Eu2O3 and from Eu3+-doped A-type La2O3 and C-type Lu2O3 were obtained at room temperature. It is suggested that the luminescence from f-f transitions in the Eu3+ ion can be used to determine the crystal structure, because the different Eu3+ ion site symmetries in the different crystal structures give rise to different characteristic spectral splitting patterns.

Selective Luminescence Spectroscopy of Poly(p-Phenylene) Thin Films at Room Temperature

1995 ◽  
Vol 413 ◽  
Author(s):  
M. A. Drobizhev ◽  
M. N. Sapozhnikov ◽  
V. M. KobryanskII
Keyword(s):  
Thin Films ◽  
Luminescence Spectrum ◽  
Room Temperature ◽  
Selective Excitation ◽  
Luminescence Spectroscopy ◽  
Luminescence Spectra ◽  
Model Calculations ◽  
Localization Threshold ◽  
Low Energy Tail ◽  
Room Temperature Luminescence

ABSTRACTSelectively excited room-temperature luminescence spectra are reported for thin films of poly(p-phenylene) (PPP) deposited onto quartz substrata. The spectra exhibit a localization threshold in the low-energy tail of the luminescence excitation band at vloc.= 22400 cm−1, 2200 cm−1 below the maximum of the excitation spectrum. Upon laser excitation at Vex < Vloc., the maximum Vem of the luminescence spectrum shifts linearly with Vex due to selective excitation of polymer segments. It was found that there exists the frequency range where the slope of the Vem vs Vex dependence is smaller than unity, which corresponds to our previous model calculations for the case of selective excitation of chromophores through broad phonon bands. At vex > vloc,, the luminescence spectrum is independent of Vex. This behavior can be explained if one assumes that upon excitation below the localization threshold the luminescence is related to polymer segments directly excited by laser, whereas upon exciting above the threshold the fast energy relaxation takes place from initially excited states to lower-lying states, from which uminescence occurs.

scholarly journals M–H–BR3 and M–Br–BR3 interactions in rhodium and nickel complexes of an ambiphilic phosphine–thioether–borane ligand

2018 ◽  
Vol 96 (5) ◽  
pp. 484-491 ◽  
Author(s):  
Bradley E. Cowie ◽  
David J.H. Emslie
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Nickel Complexes ◽  
Planar Geometry ◽  
Nmr Spectrum ◽  
X Ray ◽  
H Nmr ◽  
Square Planar ◽  
Hydride Ligand

Reaction of [Rh(μ-Cl)(CO)(TXPB)] (1; TXPB = 2,7-di-tert-butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene) with NaBH4 yielded square planar [Rh(μ-H)(CO)(TXPB)] (2) in which the hydride ligand bridges between rhodium and the borane unit of TXPB. The Rh–H, Rh–B, and Rh–Cipso distances are short at 1.84(5), 2.456(6), and 2.568(5) Å, respectively, whereas the B–H bond, 1.59(6) Å, falls at the longer end of the usual range. Compound 2 is compared with the previously reported series of rhodium TXPB complexes: [RhX(CO)(TXPB)] {X = F (3), Cl (1), Br (4), I (5)}. Compound 4 in this series features the only crystallographically characterized example of an M–Br–BR3 interaction, and to expand this area, [NiBr(μ-Br)(TXPB)] (6) was prepared via the reaction of [NiBr2(dme)2] (dme = 1,2-dimethoxyethane) with TXPB. An X-ray crystal structure of light purple 6 revealed a square-planar geometry with a strong B–Br interaction {B–Br = 2.311(6) Å; ∑(C–B–C) = 344.5(7)°}. An 11B NMR chemical shift of 23 ppm was observed for 6, indicating that an appreciable B–Br interaction is maintained in solution. No signals were observed in the 31P{1H} NMR spectrum at room temperature, whereas a broadened 31P signal was observed at −20 °C, evolving into a sharp singlet at −67 °C. This behaviour suggests that at room temperature, square planar 6 exists in equilibrium with a paramagnetic tetrahedral isomer, present at a level below that detectable through Evans magnetic measurements.

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.

Crystal structure of Diaqua(1,10-phenanthroline)copper(II) sulfate

1984 ◽  
Vol 37 (5) ◽  
pp. 1111 ◽  
Author(s):  
PC Healy ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Copper Atom ◽  
Title Compound ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Axial Coordination ◽  
Square Planar

The crystal structure of the title compound, [Cu(OH2)2(phen)] (SO4) (phen = 1,10-phenanthroline), has been determined by single-crystal X-ray diffraction methods at room temperature, being refined by full matrix least-squares methods to a residual of 0.033 for 1445 'observed' reflections. Crystals are monoclinic, C2/c, a 14.883(8), b 13.843(9), c 7.019(4) �, β 108.60(4)�, Z 4. As in a number of other copper(II) and nickel(II) derivatives with (CuL4)(SO4) stoichiometry, the pseudo-square planar copper environments [Cu-N,O: 2.009(2), 1.970(2) � in the present case] are bridged through the two axial coordination positions by sulfate groups: O.SO2.O[Cu(OH2)2(phen)]O.SO2.0, etc. to give a linear polymeric array [Cu-O(SO4), 2.468(3) �]; a crystallographic twofold axis passes through the copper atom.

Synthese und Kristallstruktur von Cs3(AuBr4)2Br3 / Synthesis and Crystal Structure of Cs3(AuBr4)2Br3

1981 ◽  
Vol 36 (12) ◽  
pp. 1504-1508 ◽  
Author(s):  
Birgit Lehnis ◽  
Joachim Strähle
Keyword(s):  
Crystal Structure ◽  
Ir Spectrum ◽  
Room Temperature ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
Stoichiometric Amount ◽  
Square Planar

Abstract Cs3(AuBr4)2Br3 is obtained in the form of red needles by adding the stoichiometric amount of CsBr to a solution of HAuBr4 and Br3- in aqueous HBr. The salt decomposes slowly at room temperature to form a mixed-valent, cubic bromo aurate(I,III), in which the linear AuBr2- ions are partially substituted by Br3- ions. At 140 °C Cs2Au2Br6 and CsBr are formed. Cs3(AuBr4)2Br3 crystallizes monoclinic with four formula units in the space group P21/c. The structure is built up by AuBr4-and Br3- anions and Cs+ cations. An average Au−Br distance of 242.2 pm was found for the square planar AuBr4- ion. The linear Br3-groups are almost symmetrical with Br−Br distances of 254.0 and 256.2 pm. Therefore only two vibrations are observed in the IR spectrum: νas = 172, δ = 56 cm-1. The absorptions of the AuBr4- groups are: νas=250, σas=113, γ=102cm-1.

Characterization, luminescent properties, and crystal structure determination of [Pt(Ph2bipy)Cl2]

2016 ◽  
Vol 57 (8) ◽  
pp. 1773
Author(s):  
S. Shamaei ◽  
A. Heidari ◽  
V. Amani
Keyword(s):  
Structure Determination ◽  
Room Temperature ◽  
Diffraction Method ◽  
Luminescent Properties ◽  
Luminescence Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Orange Solution

New complex [Pt(Ph2bipy)Cl2] (1) is obtained from the reaction of H2PtCl6×6H2O and 4,4'-diphenyl-2,2'-bipyridine (Ph2bipy) in a mixture of methanol, chloroform, and dimethyl sulfo­xide. Suitable crystals of 1 for the diffraction experiment are obtained by slow evaporation of the resulted orange solution at room temperature. This complex is characterized by elemental analysis, IR, 1H NMR, UV-Vis, and luminescence spectroscopy and its structure is studied by the single crystal X-ray diffraction method. X-ray structure determination shows that in the structure of this compound, the Pt(II) atom is four-coordinated in a distorted square-planar configuration by two nitrogen atoms from a bidentate 4,4'-diphenyl-2,2'-bipyridine ligand and two terminal chlorine atoms.

Steric Modification of M-P Bond Lengths: Crystal and Molecular-Structures of the Platinum(II) Complexes trans-(PPrI3)2ClnH2-nPtII (N = 0-2)

1986 ◽  
Vol 39 (10) ◽  
pp. 1495 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker ◽  
WA Wickramasinghe
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Room Temperature ◽  
Platinum Complexes ◽  
Molecular Structures ◽  
Crystal And Molecular Structures ◽  
Anionic Ligand ◽  
Trans Bond ◽  
Square Planar ◽  
Ligand Conformation

Crystal structure analyses of the square-planar platinum complexes trans-(PPri3)2ClnH2-nPtII(n = 0-2) (C), (B), (A) are described. Diffraction data were recorded at room temperature with a Picker FACS-1 diffractometer. Convergence R values, for reflection numbers given in parentheses, are 0.020 (2373), (A), 0.021 (5771), (B) and 0.018 (1982), (C). The ligand conformation about the Pt-P bonds is perpendicular for (A) and (B) and eclipsed for (C). The Pt-P distances decrease systematically with increasing hydride content [2.339(1)Ǻ, (A); 2.286(1)Ǻ, (B); 2.252(1)Ǻ, (C)]. The decrease reflects the low steric requirement of hydride vis a vis chloride ligands and concomitant changes in anionic ligand/phosphine substituent non-bonding interactions. The trans-bond lengthening of the Pt- Cl bond in (B)(due to trans hydride) is 0.092(1)Ǻ.

The twinned crystal structure of diiodobis(triphenylphosphine)palladium(II) dichloromethane disolvate at 173 K

2006 ◽  
Vol 62 (5) ◽  
pp. m1056-m1058
Author(s):  
Thomas Theissmann ◽  
Michael Bolte
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Title Compound ◽  
Room Temperature ◽  
Coordination Geometry ◽  
Acta Cryst ◽  
Square Planar ◽  
Twinned Crystal Structure

The structure of the title compound, [PdI2(C18H15P)2]·2CH2Cl2, has previously been reported by Debaerdemaeker, Kutoglu, Schmid & Weber [Acta Cryst. (1973), B29, 1283–1288] at room temperature. We report the structure determination of this compound from a twinned crystal at 173 (2) K. The Pd atom is located on a centre of inversion and has square-planar coordination geometry.

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