| Item type: | Article | ||||
|---|---|---|---|---|---|
| Journal or Publication Title: | Inorganic Chemistry | ||||
| Publisher: | AMER CHEMICAL SOC | ||||
| Place of Publication: | WASHINGTON | ||||
| Volume: | 39 | ||||
| Number of Issue or Book Chapter: | 4 | ||||
| Page Range: | pp. 770-777 | ||||
| Date: | 2000 | ||||
| Institutions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Hartmut Yersin | ||||
| Identification Number: |
| ||||
| Keywords: | LOCALIZED (3)PI-PI(ASTERISK) STATE; ORGANOMETALLIC DIIMINE COMPLEXES; PHOSPHORESCENT TRIPLET-STATE; LOWEST EXCITED-STATES; TIME-RESOLVED SPECTRA; RADIATIVE PROPERTIES; ELECTRONIC STATES; RHODIUM COMPLEXES; SPECTROSCOPY; FIELD | ||||
| Dewey Decimal Classification: | 500 Science > 540 Chemistry & allied sciences | ||||
| Status: | Published | ||||
| Refereed: | Yes, this version has been refereed | ||||
| Created at the University of Regensburg: | Yes | ||||
| Item ID: | 74417 |
Web of ScienceAbstract
The first spectroscopic investigation of Pd(qol)(2) (qol(-) = 8-quinolinolato-N,O = oxinate) dissolved in an n-octane matrix (Shpol'skii matrix) is reported. Application of several spectroscopic methods at liquid helium temperatures (typically, T = 1.2 K), such as site-selective and highly resolved luminescence and excitation spectroscopy, time-resolved emission spectroscopy, optically detected ...
Abstract
The first spectroscopic investigation of Pd(qol)(2) (qol(-) = 8-quinolinolato-N,O = oxinate) dissolved in an n-octane matrix (Shpol'skii matrix) is reported. Application of several spectroscopic methods at liquid helium temperatures (typically, T = 1.2 K), such as site-selective and highly resolved luminescence and excitation spectroscopy, time-resolved emission spectroscopy, optically detected magnetic resonance, microwave recovery, phosphorescence microwave double-resonance, and magnetic fields, allows us to characterize the lowest excited electronic states in detail. In accord with previous assignments for the related Pt(qol)(2) it is shown that these lowest states represent intraligand charge-transfer states, namely, (ILCT)-I-1 and (ILCT)-I-3. The electronic origin of the (ILCT)-I-1 state lies at 20 617 cm(-1) (site A). It exhibits a nearly homogeneous line width with a half-width of about 80 cm(-1) (fwhm), which corresponds to a lifetime of tau((ILCT)-I-1) approximate to 2 x 10(-13) s. This value is even shorter than that found for Pt(qol)(2), presumably due to intersystem crossings and relaxations to dd* states. The electronic origin of the (ILCT)-I-3 state lies at 16 090 cm(-1) (site A), and its zero-field splittings (zfs) into three sublevels are 2E = 2356 MHz (0.0785 cm(-1)) and D - E = 5241 MHz (0.175 cm(-1)). The emission decay times of the three sublevels are determined as tau(I) = 90 +/- 30 ms, tau(II) = 180 +/- 10 mu s, and tau(III) = 80 +/- 10 mu s. (Slightly different values are found for a second site B at 16 167 cm(-1).) From the small values of zfs and the long emission decay times it is concluded that metal-d or MLCT admixtures to (ILCT)-I-3 are very small. This result clearly reflects the ligand-centered character of the transition. The assignment as an ILCT transition is supported by the occurrence of relatively strong vibrational satellites of Pd-N and Pd-O character in highly resolved emission spectra. Although the transition is ascribed to a charge-transfer process, the geometry changes between the ground state and (ILCT)-I-3 are very small. The results found for Pd(qol)(2) are compared to those of companion studies of Pt(qot)(2) and Pt(qtl)(2) (qtl- = 8-quinolinethiolato-N,S).
Metadata last modified: 19 Dec 2024 15:59
Altmetric