Photophysics of single crystal [Pt(o‐phen) (CN)₂]: Optical properties at external magnetic fields and at high pressures

Abstract

Complex Compounds / Crystals / High Pressure Luminescence 1 Magnetic FieldsProperties of the polarized emission (energy, intensity, lifetime) of single crystal [Pt(o-phen) (CN),] as functions of temperature (1.9 K s T < 295 K), of homogeneous magnetic fields (0 i H 5 6 T), and of hydrostatic pressures (1 bar I p 5 30 kbar) are reported, and the temperature dependence of the polarized absorption is described. Between T = 1.9 K and room temperature the E l a polarized emission (E: electric field vector; a: crystallographic a axis) and the E l a polarized absorption are blue shifted by -2000 cm-' and 1400 cm-', respectively. Application of a homogeneous magnetic field H l a with field strength H = 6 T shifts the low temperature E l a emission by -190 cm-' to higher energies, shortens the lifetime by two orders of magnitude, and increases the emission intensity by a factor of -18. Increasing hydrostatic pressure between p = 1 bar and 30 kbar reduces the emission energy by -70 cm-'/kbar. The experimental results can be interpreted by a system of coupled complexes of C;, symmetry.

Polarized Optical Absorption and Emission of Pt (II)Complexes:Single Crystal [Pt(o-phen)(en)]Cl2 · 2H2O

“…Fur thermore, the decay rates of the shallow traps are dominated by the rates of the competing mechanism of trapping and detrapping. Experiments that support these predictions are reported for crystalline organic compounds [25][26][27] and for transition metal com plexes [28][29][30].…”

“…Figure 8 illustrates schematically the resulting energy level diagram for the triplet states. Corresponding models for single crystals have been established to describe the optical properties of purely organic compounds [25][26][27] as well as of transition metal chelate complexes with aro matic ligands [28][29][30],…”

Kinetics of the acid dissociation of oligopeptide complexes of copper(II) and nickel(II): a study on general-acid catalysis with "noncoordinating" 2,6-lutidine type buffers

“…Ni(H.2G3)" + 3H+ -Ni2+ + HGj* (13) experiments were carried out with solutions of Ni(H_2G3)~(adjusted to pH 9.5), which were reacted with a series of buffer solutions with different concentrations in the pH range 4.6-8. In all cases the absorbance/time data obtained could be fitted to eq 7 and the resulting rate constants are summarized in Table IV.…”

“…Table V and Figure 3 present the k^d ata obtained for reaction 13 when studied in the pH range 3-8 with differently substituted 2,6-lutidines as buffers. Since the buffers applied (lu, AC, H(LS), NL, NC, CL) no not contribute as general-acid catalysts, the dependence kobsd = /([H+]) shown in Figure 3 describes the specific-acid catalysis for reaction 13. It is very satisfying to see that the data obtained with the different buffers complement each ir.4…”

“…Figure 3. Dependence of the experimental rate constant kob!i at 298 K for reaction 13 on the concentration of H30+ in the pH range 7.4-3.1 (the symbol + corresponds to MES; for the other symbols see Table V).…”