Intramolecular Luminescence Quenching in Amino Acid Bridged Ruthenium(II)-Copper(II) Complexes with Negligible Ground-State Coupling
✍ Scribed by Bernd Geißer; Ralf Alsfasser
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 333 KB
- Volume
- 1998
- Category
- Article
- ISSN
- 1434-1948
No coin nor oath required. For personal study only.
✦ Synopsis
A series of heterobimetallic complexes [{Ru(bipy) 2 }m-However, the luminescence of 1b-4b is significantly quenched compared to that of the parent compounds 1a-4a.
Quenching was found to proceed only intramolecularly and to be most efficient in 1b with the shortest alkyl spacer. L-2,3-diaminopropionic acid; 2b, L-2,4-diaminobutyric acid; 3b, L-ornithine, 4b, L-lysine) has been synthesized and Equilibrium constants for the formation of 1b-4b were determined from luminescence titrations of the respective characterized starting from the 2,2'-bipyridineruthenium(II)substituted amino acids [{Ru(bipy) 2 }m-AA-α N-t Boc] 2+ ( α N-ruthenium-substituted amino acid with [Cu(phen)(NO 3 ) 2 ].
The complexes 2b-4b (K = 1.61-2.08 × 10 7 M -1 ) were found t Boc-1a-4a, α N-t Boc = N α -tert-butoxycarbonyl). The metal centers in 1b-4b are bridged by insulating alkyl chains. to be significantly more stable than 1b (K = 5.7 × 10 6 M -1 ). This is explained by a stronger electrostatic repulsion Consequently, spectroscopic and electrochemical investigations confirmed the absence of any appreciable ground-between the two metal centers in the latter compound. state coupling between ruthenium(II) and copper(II).