Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states

Jon R. Kirchhoff, Roland E. Gamache, Marcus W. Blaskie, Alan A. Del Paggio, Russell K. Lengel, David R. McMillin

Research output: Contribution to journalArticle

205 Citations (Scopus)

Abstract

The photophysical properties of a series of homochelated complexes of the type Cu(NN)2+ are reported where (NN) denotes a heteroaromatic ligand. For the (NN) ligands 2,9-dimethyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and 4,4′,6,6′-tetramethyl-2,2′-bipyridine, the emission quantum yields are 2.1 × 10-4, 2.5 × 10-4, and 0.5 × 10-4, respectively, in CH2Cl2 solution at 25°C. Under these conditions the lifetimes are 90, 80, and 18 ns, respectively, for the same series of compounds. In each case the emission intensity is found to decrease as the solution temperature is lowered. This is interpreted in terms of two emitting states where the population of the upper level, which has a more favorable radiative rate constant, requires thermal energy. Detailed temperature studies of the 2,9-dimethyl-1,10-phenanthroline complex have been carried out, and the results have been analyzed by assuming that the two excited states are thermally equilibrated. We conclude that the lowest energy emitting state exhibits a radiative rate constant of ca. 103 s-1, typical of a triplet state. The other state lies some 1800 cm-1 to higher energy and exhibits a radiative rate constant of ca. 107 s-1. This state is ascribed singlet multiplicity. Tentatively, both states are assumed to derive from the lowest energy charge-transfer configuration of the complex.

Original languageEnglish (US)
Pages (from-to)2380-2384
Number of pages5
JournalInorganic Chemistry
Volume22
Issue number17
StatePublished - 1983
Externally publishedYes

Fingerprint

Excited states
Luminescence
Rate constants
luminescence
temperature dependence
Fluids
fluids
Ligands
excitation
ligands
Quantum yield
Thermal energy
thermal energy
Temperature
atomic energy levels
energy
Charge transfer
charge transfer
life (durability)
temperature

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

Kirchhoff, J. R., Gamache, R. E., Blaskie, M. W., Del Paggio, A. A., Lengel, R. K., & McMillin, D. R. (1983). Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states. Inorganic Chemistry, 22(17), 2380-2384.

Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states. / Kirchhoff, Jon R.; Gamache, Roland E.; Blaskie, Marcus W.; Del Paggio, Alan A.; Lengel, Russell K.; McMillin, David R.

In: Inorganic Chemistry, Vol. 22, No. 17, 1983, p. 2380-2384.

Research output: Contribution to journalArticle

Kirchhoff, JR, Gamache, RE, Blaskie, MW, Del Paggio, AA, Lengel, RK & McMillin, DR 1983, 'Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states', Inorganic Chemistry, vol. 22, no. 17, pp. 2380-2384.
Kirchhoff JR, Gamache RE, Blaskie MW, Del Paggio AA, Lengel RK, McMillin DR. Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states. Inorganic Chemistry. 1983;22(17):2380-2384.
Kirchhoff, Jon R. ; Gamache, Roland E. ; Blaskie, Marcus W. ; Del Paggio, Alan A. ; Lengel, Russell K. ; McMillin, David R. / Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states. In: Inorganic Chemistry. 1983 ; Vol. 22, No. 17. pp. 2380-2384.
@article{fbb835b878d64e3fa57447df883d0640,
title = "Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states",
abstract = "The photophysical properties of a series of homochelated complexes of the type Cu(NN)2+ are reported where (NN) denotes a heteroaromatic ligand. For the (NN) ligands 2,9-dimethyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and 4,4′,6,6′-tetramethyl-2,2′-bipyridine, the emission quantum yields are 2.1 × 10-4, 2.5 × 10-4, and 0.5 × 10-4, respectively, in CH2Cl2 solution at 25°C. Under these conditions the lifetimes are 90, 80, and 18 ns, respectively, for the same series of compounds. In each case the emission intensity is found to decrease as the solution temperature is lowered. This is interpreted in terms of two emitting states where the population of the upper level, which has a more favorable radiative rate constant, requires thermal energy. Detailed temperature studies of the 2,9-dimethyl-1,10-phenanthroline complex have been carried out, and the results have been analyzed by assuming that the two excited states are thermally equilibrated. We conclude that the lowest energy emitting state exhibits a radiative rate constant of ca. 103 s-1, typical of a triplet state. The other state lies some 1800 cm-1 to higher energy and exhibits a radiative rate constant of ca. 107 s-1. This state is ascribed singlet multiplicity. Tentatively, both states are assumed to derive from the lowest energy charge-transfer configuration of the complex.",
author = "Kirchhoff, {Jon R.} and Gamache, {Roland E.} and Blaskie, {Marcus W.} and {Del Paggio}, {Alan A.} and Lengel, {Russell K.} and McMillin, {David R.}",
year = "1983",
language = "English (US)",
volume = "22",
pages = "2380--2384",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "17",

}

TY - JOUR

T1 - Temperature dependence of luminescence from Cu(NN)2+ systems in fluid solution. Evidence for the participation of two excited states

AU - Kirchhoff, Jon R.

AU - Gamache, Roland E.

AU - Blaskie, Marcus W.

AU - Del Paggio, Alan A.

AU - Lengel, Russell K.

AU - McMillin, David R.

PY - 1983

Y1 - 1983

N2 - The photophysical properties of a series of homochelated complexes of the type Cu(NN)2+ are reported where (NN) denotes a heteroaromatic ligand. For the (NN) ligands 2,9-dimethyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and 4,4′,6,6′-tetramethyl-2,2′-bipyridine, the emission quantum yields are 2.1 × 10-4, 2.5 × 10-4, and 0.5 × 10-4, respectively, in CH2Cl2 solution at 25°C. Under these conditions the lifetimes are 90, 80, and 18 ns, respectively, for the same series of compounds. In each case the emission intensity is found to decrease as the solution temperature is lowered. This is interpreted in terms of two emitting states where the population of the upper level, which has a more favorable radiative rate constant, requires thermal energy. Detailed temperature studies of the 2,9-dimethyl-1,10-phenanthroline complex have been carried out, and the results have been analyzed by assuming that the two excited states are thermally equilibrated. We conclude that the lowest energy emitting state exhibits a radiative rate constant of ca. 103 s-1, typical of a triplet state. The other state lies some 1800 cm-1 to higher energy and exhibits a radiative rate constant of ca. 107 s-1. This state is ascribed singlet multiplicity. Tentatively, both states are assumed to derive from the lowest energy charge-transfer configuration of the complex.

AB - The photophysical properties of a series of homochelated complexes of the type Cu(NN)2+ are reported where (NN) denotes a heteroaromatic ligand. For the (NN) ligands 2,9-dimethyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and 4,4′,6,6′-tetramethyl-2,2′-bipyridine, the emission quantum yields are 2.1 × 10-4, 2.5 × 10-4, and 0.5 × 10-4, respectively, in CH2Cl2 solution at 25°C. Under these conditions the lifetimes are 90, 80, and 18 ns, respectively, for the same series of compounds. In each case the emission intensity is found to decrease as the solution temperature is lowered. This is interpreted in terms of two emitting states where the population of the upper level, which has a more favorable radiative rate constant, requires thermal energy. Detailed temperature studies of the 2,9-dimethyl-1,10-phenanthroline complex have been carried out, and the results have been analyzed by assuming that the two excited states are thermally equilibrated. We conclude that the lowest energy emitting state exhibits a radiative rate constant of ca. 103 s-1, typical of a triplet state. The other state lies some 1800 cm-1 to higher energy and exhibits a radiative rate constant of ca. 107 s-1. This state is ascribed singlet multiplicity. Tentatively, both states are assumed to derive from the lowest energy charge-transfer configuration of the complex.

UR - http://www.scopus.com/inward/record.url?scp=33845550112&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33845550112&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:33845550112

VL - 22

SP - 2380

EP - 2384

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 17

ER -