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Ruthenium Bis(terpyridine) Complexes Based on D‐P‐A Functionalization: Experimental and Theoretical Evidences
Author(s) -
Rana Prem Jyoti Singh,
Singh Pallavi,
Kar Prasenjit
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201700927
Subject(s) - homo/lumo , excited state , photochemistry , materials science , ruthenium , terpyridine , electron transfer , electrochemistry , time dependent density functional theory , metal , chemistry , electrode , catalysis , atomic physics , organic chemistry , molecule , physics , metallurgy
We have synthesized heteroleptic complexes 1–4 with improved photophysical properties efficient for interfacial charge injection to semiconducting TiO 2 nanoparticle. The complexes show improved optical properties with τ a v g varying from 7.18 ns to 3.89 ns, which is greater than 0.25 ns for [Ru(tpy) 2 ](PF 6 ) 2 and sufficient to perform the interfacial electron transfer study with semiconducting TiO 2 . The time‐correlated single photon counting (TCSPC) measurement with colloidal TiO 2 show quenched decay pattern and decreased lifetime. The electrochemical study exhibit the oxidation potential ( E o x ) in the range of 1.11‐1.17 V vs Ag/AgCl reference electrode and found to be shifted cathodically compared to 1.32 V for [Ru(tpy) 2 ](PF 6 ) 2 . This cathodic shift is due to the presence of electron donating group that make the metal centre more prone to oxidation and the related excited state oxidation potential show stronger reductant behavior in MLCT excited state. Also, the transient absorption studies with TiO 2 nanoparticle is in good harmony with photoinduced electron injection from LUMO of complexes to the conduction band (CB) of TiO 2 as LUMO level of complexes were above the CB of TiO 2 (‐3.65 eV). Further, the theoretical (TDDFT) data is in good agreement with experimental data.