Electrochemical and Photophysical Study of Homoleptic and Heteroleptic Methylated Ru(II) Bis?terpyridine Complexes

In this study, we investigate the impact of N-methylation on electronic and photophysical properties both homoleptic heteroleptic Ru(II) bis-terpyridine complexes based recently reported ligand 4’-(4-bromophenyl)-4,4’’’: 4’’,4’’’’-dipyr-idinyl-2,2’ : 6’,2’’-terpyridine (Bipytpy), with pyridine substituents in 4- 4’’-position. The first reduction methylated takes place at pyridinium site is observed as multi-electron process. Following N-methylation, exhibit higher luminescence quantum yields longer excited-state lifetimes. Interestingly, are rather similar. TD-DFT calculations support experimental results. Furthermore, tested photosensitizers for photocatalytic hydrogen production, parent complex 1[Ru(Bipytpy)(Tolyltpy)](PF \(_6\))\(_2\) (Tolyltpy: 4’-tolyl-2,2’: 6’,2’’-terpyri-dine) was shown to be active highly stable underphotocatalytic conditions. However, herein inactive under chosen conditions, presumably due loss methyl groups, converting them non-methylated complexes.