Multiple state emission and related phenomena in transition metal complexes

DeArmond, M. Keith; Carlin, Clifford M.

doi:10.1016/s0010-8545(00)80502-0

Cited by 164 publications

(40 citation statements)

References 75 publications

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“…Related studies had been summarized much earlier (in 1981) in a lengthy review by DeArmond and Carlin in this journal [17]. The emphasis in that 1981 review was not on the novelty of dual emission even then, but on establishing the spatially isolated nature of emitting states [17]. It seems to us that the earliest papers had often or always used the word "localized" to refer to metal-centered dd* excited states, putting emphasis on how metal-containing compounds were different from organic compounds.…”

Section: 3mentioning

confidence: 86%

“…He continues, however, by pointing out that detecting such dual emission would be difficult "due to the fact that the MLCT emissions would have virtually identical energies, contours, and lifetimes …" He then argued that he had obtained data good enough to resolve such spatially localized 3 MLCT dual emission at 77 K in one particular case. Related studies had been summarized much earlier (in 1981) in a lengthy review by DeArmond and Carlin in this journal [17]. The emphasis in that 1981 review was not on the novelty of dual emission even then, but on establishing the spatially isolated nature of emitting states [17].…”

Section: 3mentioning

confidence: 99%

“…Studies using other techniques agreed. Electron paramagnetic resonance as well as polarized optical measurements and photoselection were reviewed and discussed in the DeArmond review [17], including both work from DeArmond's own laboratory and work of others. Interest continues to the present day, with reports of results obtained by transient infrared spectroscopy appearing not long ago [20].…”

Section: 3mentioning

confidence: 99%

See 2 more Smart Citations

So-called “dual emission” for 3MLCT luminescence in ruthenium complex ions: What is really happening?

Magde

Glazer

2016

Coordination Chemistry Reviews

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Section: 3mentioning

confidence: 86%

Section: 3mentioning

confidence: 99%

Section: 3mentioning

confidence: 99%

See 1 more Smart Citation

So-called “dual emission” for 3MLCT luminescence in ruthenium complex ions: What is really happening?

Magde

Glazer

2016

Coordination Chemistry Reviews

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“…38 For example, in compounds such as Ru(dcb)(bpy) 2 2 þ , where dcb is 4,4 0 -(CO 2 H) 2 -bpy, the electron-withdrawing carboxylic acid groups lower the energy of the bipyridine p Ã orbitals resulting in a redshifted MLCT absorption. The dcb ligand is more easily reduced relative to bpy due to the same inductive effects by the carboxylic acid groups.…”

Section: Metal-to-ligand Charge Transfer Excited Statesmentioning

confidence: 99%

Solar Photochemistry with Transition Metal Compounds Anchored to Semiconductor Surfaces

Meyer

2010

Physical Inorganic Chemistry

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There exists a critical need for sustainable power on a terawatt (TW ¼ 10 12 W) scale. 1,2 As the world's need for energy is related to the number of people on Earth, a staggering 45% population growth over the last quarter-century equates to roughly 2 billion people and a 6 TW ($63%) increase in needed power. 3 In addition, the urbanism of third-world and industrialized nations and cities has led to an increase in the demand for fuel that has driven gas and oil prices to record highs. 3 Regardless of price, the continued use of fossil fuels cannot be a long-term solution as they come from a limited stock and the deleterious environmental consequences of their combustion have become self-evident. 4,5 The increased average global temperature and rates of glacial melting measured over the past few decades are telling signs. [6][7][8][9] Concern should be elicited as ice-core data correlate temperature with greenhouse gas concentrations over the past half-a-million years. The present 380 ppm atmospheric CO 2 levels exceed any values attained over the same time period. 5,6 Further, other than natural photosynthesis, there exist no obvious means by which we can decrease today's level. Thus, population, energy demand, and fuel prices do not convey the severity of the need for sustainable energy.It is our belief that molecular assemblies, particularly molecules arranged at semiconductor interfaces, will one day efficiently harvest and convert energy from the Sun, thereby providing sustainable, carbon-neutral power for future generations. The Sun is in fact the only source that on its own can provide the TWs of power needed. It has been shown that the amount of solar energy reaching the Earth in one day could power the planet for an entire year. 7,8 Remaining is the important challenge of harvesting, converting, and storing this energy in a cost-effective way. Coordination Physical Inorganic Chemistry: Reactions, Processes, and Applications Edited by Andreja Bakac

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“…It has long been recognized that the emissive state of Rh(III)-(aza)-aromatic compounds is primarily of ligand-localized 3 pp* nature [51][52][53][54]. This assignment for the Rh 3+ (4d 6 ) chelate emission is mainly based on the resemblance of the emission spectra of the free and coordinated ligand molecules.…”

Section: Odmrmentioning

confidence: 99%

Excited State Spectroscopy and Excited State Dynamics of Rh(III) and Pd(II) Chelates as Studied by Optically Detected Magnetic Resonance Techniques

Glasbeek

2000

Transition Metal and Rare Earth Compounds

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In this paper we review optically detected magnetic resonance (ODMR) investigations of a series of Rh 3+ (4d 6 ) and Pd 2+ (4d 8 ) complexes in the lowest excited electron spin triplet state. Starting with a brief survey of the technique of optical detection of magnetic resonance, zerofield and low-magnetic field ODMR results are reviewed for the tris-diimine chelates [Rh(phen) n (bpy) 3-n ] 3+ , where phen = 1,10-phenanthroline, bpy = 2,2¢-bipyridine, and n = 0, 2, or 3, and for the mixed cyclometalated chelates [Rh(thpy) x (phpy) 2-x (bpy)] + , with thpy = 2,2¢thienylpyridinate, phpy -= 2-phenylpyridinate, and x = 1, or 2. The ODMR data reveal fine structure splittings in the phosphorescent excited state of the complexes comparable in magnitude to those known for the nonchelated ligand molecules in the excited triplet state. Anisotropy studies of the ODMR spectra for the single crystals in low magnetic fields show that the lowest electronic excitation in the complexes is a triplet state indeed and that this state is localized on a single ligand molecule per metal ion site. From microwave recovery experiments, performed under conditions that the spin-lattice relaxation can be neglected (T≤ 2 K), detailed information concerning the triplet sublevel lifetimes is obtained. The lifetimes are on the millisecond timescale, i.e., three orders of magnitude shorter than for the nonchelated ligand molecules. The lifetime shortening as well as the observed spin-selective radiative decay of the triplet sublevels of the ligand molecule are discussed in detail on the basis of enhanced spin-orbit couplings caused by the central (heavy) metal ion. Optically detected spin coherence experiments (transient nutation and spin echo decay) are also discussed. The results show that the homogeneous line broadening of the ODMR transitions of the metal complexes in the emissive triplet state is approximately 100 kHz. The homogeneous broadening is attributed to the effects of flip-flop motions of ligand proton spins that randomly modulate the triplet electron spin levels on account of dipolar electron spin -nuclear spin couplings. Finally, recent ODMR and PMDR (phosphorescence microwave double resonance) experiments performed for the Pd 2+ -chelates, Pd(thpy) 2 and Pd(qol) 2 (with qol -= 8-hydroxyquinolinate) in Shpol'skii matrices are discussed. The lowest excited electronic state in these molecules is also emissive and ODMR spectra at zero-and low magnetic fields have been observed. For Pd(thpy) 2 only one zero-field ODMR transition could be measured, but it is argued that this transition originates in an excited triplet state. The results of the microwave recovery experiments could be related to time-resolved emission experiments in high magnetic fields. Spin selectivity in the vibronic line emission is demonstrated by means of PMDR.

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Multiple state emission and related phenomena in transition metal complexes

Cited by 164 publications

References 75 publications

So-called “dual emission” for 3MLCT luminescence in ruthenium complex ions: What is really happening?

So-called “dual emission” for 3MLCT luminescence in ruthenium complex ions: What is really happening?

Solar Photochemistry with Transition Metal Compounds Anchored to Semiconductor Surfaces

Excited State Spectroscopy and Excited State Dynamics of Rh(III) and Pd(II) Chelates as Studied by Optically Detected Magnetic Resonance Techniques

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