Careers in Law

2009/02/24. Tells about his journey toward law and his experience in school and as practicing lawyer. SPU alum and Seattle Lawyer, Ellis, Li, and McKinstry

Substituent effects on the photophysical properties of bis(1,10-phenanthroline)copper(I) and bis(2,2\u27:6\u272\u27\u27-terpyridine)ruthenium(II) complexes

The charge-transfer (CT) absorption spectra and the emission spectra of a series of Cu(NN)\sb2\sp+ complexes, where NN denotes a chelating, heteroaromatic ligand, have been measured in different solvent systems at room temperature and at 90K. In most cases the absorption spectra can be assigned in terms of effective D\sb{\rm 2d} symmetry. The major bands in the visible region are attributed to z-polarized CT transitions to the \Psi\sp{\*} and \chi\sp{\*} orbitals of the ligand, where the z axis is taken as the line joining the metal and ligand centers. For phenanthroline complexes these transitions are poorly resolved unless there are phenyl groups in the 2,9-positions. The emission results illustrate the fact that bulky ligands are required to avoid solvent-induced quenching of the excited state in donor media via a type of exciplex quenching. Even CH\sb2Cl\sb2 is a strong enough Lewis base to induce quenching. No emission was detected form bis (1,10-phenanthroline)copper(I) at room temperature or in frozen solution. Comparisons of solution and solid state absorbance data reveal that Cu(dpp)\sb2\sp+ (where dpp denotes 2,9-diphenyl-1,10-phenanthroline) and the related copper(I) catenate Cu(cat-30)\sp+ adopt low-symmetry structures in solution which mimic those found in the solid state. Spectral changes also occur in solution upon cooling. In CH\sb2Cl\sb2 at 25\sp\circC the excited-state lifetimes of Cu(cat-30)\sp+, Cu(dpp)\sb2\sp+ and Cu(cat-27)\sp+ are 190, 250 and 280 ns, respectively. The copper(I) catenates are weak photooxidants. The data suggest that reductive quenching is difficult to observe because the excited state is only mildly oxidizing (E\sb{1/2} $\approx$ 0.4 V vs SHE). The temperature dependent luminescence lifetimes for a series of bis(2,2\sp\prime:6\sp\prime,2\sp{\prime\prime}-terpyridine)Ru(II) complexes have been measured. The data shows that phenyl groups on the ligands increase the barrier to quenching of the \sp3MLCT state via the \sp3d-d states. The barriers range from 1480 cm\sp{-1} for Ru(tpy)\sb2\sp{2+} (tpy denotes 2,2\sp\prime:6\sp\prime,2\sp{\prime\prime}-terpyridine) to 2180 cm\sp{-1} when the terpyridine ligand is 4,4\sp\prime-diphenyl-2,2\sp\prime:6\sp\prime,2\sp {\prime\prime}-terpyridine or 4,4\sp\prime,4\sp {\prime\prime}-triphenyl-2,2\sp\prime:6\sp\prime,2\sp {\prime\prime}-terpyridine. The preparation of phenylated ligands and the corresponding Ru(II) complexes are described

1,4,5,8-tetra-azaphenanthrene Complexes of Copper(i) and Silver(i)

Cu(l) and Ag(l) complexes of 1,4,5,8‐tetra‐azaphenanthrene (TAP) and of two of its methylated derivatives (3,6‐dimethyl‐ and 2,3,6,7‐tetramethyl‐) have been made and characterized. Their HNMR spectra are discussed. The structure of the complex Ag(TAP)2(NO3), as determined by X‐Ray crystallography, is that of a strongly folded and twisted square planar arrangement of the chelating ligands around the silver atom; the four Ag‐N bonds are not equal: they are shorter (2.36 Å) in one pair of trans bonds than in the other (2.56 Å). 3,6‐Dimethyl‐1,4,5,8‐tetra‐azaphenanthrene (3,6dmTAP), a new TAP derivative, has been synthesized starting from 2‐hydroxy‐3‐methylquinoxaline which was nitrated, then treated with POCl3, the resulting 2‐chloro‐3‐methyl‐6‐nitroquinoxaline reacted with hydrazine and the hydrazino group oxidized to give 3‐methyl‐6‐nitroquinoxaline. This was aminated with hydroxylamine, reduced to the diamine and finally condensed with glyoxal to give 2,6‐dimethyl‐ and 3,6‐dimethyl‐1,4,5,8‐tetra‐azaphenanthrene. Copyright © 1988 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe