TY - JOUR
T1 - The influence of ligand localized excited states on the photophysics of second row and third row transition metal terpyridyl complexes
T2 - Recent examples and a case study
AU - Gu, Jing
AU - Yan, Yong
AU - Helbig, Brian J.
AU - Huang, Zhuangqun
AU - Lian, Tianquan
AU - Schmehl, Russell H.
N1 - Funding Information:
RHS wishes to thank the U.S. Department of Energy, Office of Basic Energy Sciences ( DE-FG-02-96ER14617 ). TL is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Solar Photochemistry Program ( DE-FG02-12ER16347 ). We also thank the U.S. National Science Foundation (grant CHE0619770 ) for funding the ESI mass spectrometer. J.G. thanks the IBM Corporation for a fellowship in Computational Science administered through the Tulane Center for Computational Science.
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - The photophysical behavior of Ru(II) and Os(II) diimine complexes having complex aromatic hydrocarbon diimine ligands has received considerable attention as systems exhibiting intramolecular energy transfer to yield excited states with lifetimes much longer than the parent diimine complexes. Here we present a focused discussion of the photophysical behavior of transition metal complexes with modified terpyridyl ligands. The overview includes, as an example of approaches used to evaluate such systems, spectroscopic studies of a pair of Ru(II) mono- and bis-terpyridyl complexes modified with vinylpyrene (Pyr-v-tpy) to have ligand localized excited states that are equal to or lower than the energy of the known MLCT state of the parent complexes, [Ru(Mpt)2]2+ and [Ru(Mpt)(dien)]2+ (Mpt=4'-tolyl-2,2':6',2″-terpyridine, dien=diethylenetriamine). The common observation is that the presence of Pyr-v-tpy serves to lengthen the excited state lifetime of the complex through interaction of MLCT and ligand localized (IL) states. For [Ru(Pyr-v-tpy)2]2+ the excited state lifetime increases by a factor of more than 104 relative to [Ru(Mpt)2]2+. For [Ru(Pyr-v-tpy)(dien)]2+, the 3IL state is close in energy to the MLCT state of the parent [Ru(Mpt)(dien)]2+ and, while the transient absorption spectrum is significantly perturbed relative to [Ru(Mpt)(dien)]2+, the excited state decay rate changes by only a factor of four. The long-lived excited state is formed in less than a ps, indicating strong coupling of the MLCT and ligand localized manifolds.
AB - The photophysical behavior of Ru(II) and Os(II) diimine complexes having complex aromatic hydrocarbon diimine ligands has received considerable attention as systems exhibiting intramolecular energy transfer to yield excited states with lifetimes much longer than the parent diimine complexes. Here we present a focused discussion of the photophysical behavior of transition metal complexes with modified terpyridyl ligands. The overview includes, as an example of approaches used to evaluate such systems, spectroscopic studies of a pair of Ru(II) mono- and bis-terpyridyl complexes modified with vinylpyrene (Pyr-v-tpy) to have ligand localized excited states that are equal to or lower than the energy of the known MLCT state of the parent complexes, [Ru(Mpt)2]2+ and [Ru(Mpt)(dien)]2+ (Mpt=4'-tolyl-2,2':6',2″-terpyridine, dien=diethylenetriamine). The common observation is that the presence of Pyr-v-tpy serves to lengthen the excited state lifetime of the complex through interaction of MLCT and ligand localized (IL) states. For [Ru(Pyr-v-tpy)2]2+ the excited state lifetime increases by a factor of more than 104 relative to [Ru(Mpt)2]2+. For [Ru(Pyr-v-tpy)(dien)]2+, the 3IL state is close in energy to the MLCT state of the parent [Ru(Mpt)(dien)]2+ and, while the transient absorption spectrum is significantly perturbed relative to [Ru(Mpt)(dien)]2+, the excited state decay rate changes by only a factor of four. The long-lived excited state is formed in less than a ps, indicating strong coupling of the MLCT and ligand localized manifolds.
KW - Diethylenetriamine
KW - Excited state lifetime
KW - ILCT
KW - Intraligand
KW - MLCT
KW - Ruthenium
KW - Terpyridyl complexes
KW - Transient absorption
UR - http://www.scopus.com/inward/record.url?scp=84911438711&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84911438711&partnerID=8YFLogxK
U2 - 10.1016/j.ccr.2014.06.028
DO - 10.1016/j.ccr.2014.06.028
M3 - Review article
AN - SCOPUS:84911438711
SN - 0010-8545
VL - 282-283
SP - 100
EP - 109
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
ER -