On the comparison of different tests for identification of a compound from its mass spectrum

AbstractIt is shown that identification tests of different dimensions or dimensionless should not be evaluated (for their efficiency to identify molecules from their mass spectrum) by comparing the tests for a molecule itself (repeated measurements) with other molecules. This kind of tests must have similar dimensions (units). Another possibility is the comparison of tests on the basis of success of correct prediction for “unknown” molecules from a library of standards

High-field (high-frequency) EPR spectroscopy and structural characterization of a novel manganese(III) corrole

The X-ray structure, magnetic susceptibility, and high-field (high-frequency) EPR spectrum of manganese 5,10,15-tris(pentafluorophenyl) corrole unambiguously establish that the complex contains an isolated, slightly rhombic, manganese(III) center

Photoexcitations in polythiophene at high pressure

Journal ArticleWe report optical-absorption, photoluminescence (PL), and picosecond photoinduced absorption (PA) decay in films of poly-3-hexyl-thiophene at pressures up to 80 kbar. The spectral bands redshift nonlinearly with pressure and the PL intensity decreases markedly. Thermochromic transitions are completely inhibited at pressures as low as 14 kbar. The picosecond recovery of the PA decay at high pressure is similar to that of unpressed polythiophene, but has a power-law exponent consistent with more ordered chains at high pressure. These effects suggest changes with pressure in the chain conformation and in the electronic polarizability; no changes in the interchain transfer integral are observed

High-pressure effects on ultrafast-relaxation kinetics of excitons in polydiacetylene 4BCMU

Journal ArticleUltrafast-relaxation kinetics of the singlet excitons in polydiacetylene 4BCMU was measured at hydrostatic pressures up to 80 kbar, using the pump-probe photoinduced-absorption technique with 70-fs resolution at 2 eV and 5 ps in the spectral range 1.2-2.2 eV. The 100-fs decay component survives at high pressures, but the slow component evolves from a 1.5-ps exponential decay at atmospheric pressure to a much slower stretched-exponential decay at high pressures with a complete recovery in the ns time range. Results suggest that the fast decay component is a ID relaxation process, whereas the slow component is due to exciton recombination which requires a subsequent 3D distortion of the polymer chain

Optically detected magnetic resonance study of recombination mechanisms in polythiophene

Journal ArticleFrom detailed optically detected magnetic resonance measurements in polythiophene, we show that the g=2.003 signal is luminescence enhancing, and that the signal comes from a broad photoluminescence band peaking near 1.65 eV. This band is tentatively assigned to the radiative recombination of polarons, with lifetimes between 10-8 and 5x10-5 sec

Structures and Reactivity Patterns of Group 9 Metallocorroles

Group 9 metallocorroles 1-M(PPh_3) and 1-M(py)_2 [M = Co(III), Rh(III), Ir(III); 1 denotes the trianion of 5,10,15-tris-pentafluorophenylcorrole] have been fully characterized by structural, spectroscopic, and electrochemical methods. Crystal structure analyses reveal that average metal−N(pyrrole) bond lengths of the bis-pyridine metal(III) complexes increase from Co (1.886 Å) to Rh (1.957 Å)/Ir (1.963 Å); and the average metal−N(pyridine) bond lengths also increase from Co (1.995 Å) to Rh (2.065 Å)/Ir (2.059 Å). Ligand affinities for 1-M(PPh_3) axial coordination sites increase dramatically in the order 1-Co(PPh_3) < 1-Rh(PPh_3) < 1-Ir(PPh_3). There is a surprising invariance in the M(+/0) reduction potentials within the five- and six-coordinate corrole series, and even between them; the average M(+/0) potential of 1-M(PPh_3) is 0.78 V vs Ag/AgCl in CH_2Cl_2 solution, whereas that of 1-M(py)_2 is 0.70 V under the same conditions. Electronic structures of one-electron-oxidized 1-M(py)_2 complexes have been assigned by analysis of electron paramagnetic resonance spectroscopic measurements: oxidation is corrole-centered for 1-Co(py)_2 (g = 2.008) and 1-Rh(py)_2 (g = 2.003), and metal-centered for 1-Ir(tma)_2 (g_(zz) = 2.489, g_(yy) = 2.010, g_(xx) = 1.884, g_(av) = 2.128) and 1-Ir(py)_2 (g_(zz) = 2.401, g_(yy) = 2.000, g_(xx) = 1.937, g_(av) = 2.113)

Iodinated Aluminum(III) Corroles with Long-Lived Triplet Excited States

The first reported iodination of a corrole leads to selective functionalization of the four C–H bonds on one pole of the macrocycle. An aluminum(III) complex of the tetraiodinated corrole, which exhibits red fluorescence, possesses a long-lived triplet excited state