JOURNAL ARTICLE
RESEARCH SUPPORT, N.I.H., EXTRAMURAL
RESEARCH SUPPORT, NON-U.S. GOV'T
RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
Add like
Add dislike
Add to saved papers

Unusual Role of Excited State Mixing in the Enhancement of Photoinduced Ligand Exchange in Ru(II) Complexes.

Four Ru(II) complexes were prepared bearing two new tetradentate ligands, cyTPA and 1-isocyTPQA, which feature a piperidine ring that provides a structurally rigid backbone and facilitates the installation of other donors as the fourth chelating arm, while avoiding the formation of stereoisomers. The photophysical properties and photochemistry of [Ru(cyTPA)(CH3 CN)2 ]2+ (1), [Ru(1-isocyTPQA)(CH3 CN)2 ]2+ (2), [Ru(cyTPA)(py)2 ]2+ (3), and [Ru(1-isocyTPQA)(py)2 ]2+ (4) were compared. The quantum yield for the CH3 CN/H2 O ligand exchange of 2 was measured to be Φ400 = 0.033(3), 5-fold greater than that of 1, Φ400 = 0.0066(3). The quantum yields for the py/H2 O ligand exchange of 3 and 4 were lower, 0.0012(1) and 0.0013(1), respectively. DFT and related calculations show the presence of a highly mixed 3 MLCT/3 ππ* excited state as the lowest triplet state in 2, whereas the lowest energy triplet states in 1, 3, and 4 were calculated to be 3 LF in nature. The mixed 3 MLCT/3 ππ* excited state places significant spin density on the quinoline moiety of the 1-isocyTPQA ligand positioned trans to the photolabile CH3 CN ligand in 2, suggesting the presence of a trans-type influence in the excited state that enhances ligand exchange. Ultrafast spectroscopy was used to probe the excited states of 1-4, which confirmed that the mixed 3 MLCT/3 ππ* excited state in 2 promotes ligand dissociation, representing a new manner to effect photoinduced ligand exchange. The findings from this work can be used to design improved complexes for applications that require efficient ligand dissociation, as well as for those that require minimal deactivation of the 3 MLCT state through low-lying metal-centered states.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app