| Autor: |
Nemez DB; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada., Lozada IB; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada., Braun JD; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada., Williams JAG; Department of Chemistry, Durham University, Durham DH1 3LE, U.K., Herbert DE; Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada. |
| Jazyk: |
angličtina |
| Zdroj: |
Inorganic chemistry [Inorg Chem] 2022 Aug 29; Vol. 61 (34), pp. 13386-13398. Date of Electronic Publication: 2022 Aug 16. |
| DOI: |
10.1021/acs.inorgchem.2c01514 |
| Abstrakt: |
The synthesis, characterization, and coordination chemistry of a doubly π-extended bipyridine analogue, 6,6'-biphenanthridine (biphe), is presented. The structure of the molecule has been determined in the solid state by X-ray diffraction, showing an angle of 72.6° between the phenanthridine planes. The free, uncoordinated organic molecule displays blue fluorescence in solution. It can be singly protonated with strong acids, and the protonated form displays more intense yellow emission. The effect of acid on the excited states is interpreted with the aid of TDDFT calculations. Two Ru(II) coordination complexes, tris(6,6'-biphenanthridine)ruthenium(II) dichloride, [Ru(biphe) 3 ]Cl 2 , and bis(2,2'-bipyridine)(6,6'-biphenanthridine)ruthenium(II) tetraphenylborate, [Ru(bpy) 2 (biphe)](BPh 4 ) 2 , are also reported and their structures determined in the solid state by X-ray diffraction. Both complexes display emission at 77 K that is strongly bathochromically shifted by almost 200 nm compared to that of the archetypal 3 MLCT emitter [Ru(bpy) 3 ] 2+ . Such a red shift is consistent with the more extended conjugation and lower-energy π* orbitals associated with the biphe ligand, lowering the energy of the 3 MLCT excited state, as revealed by TDDFT calculations. The efficient non-radiative decay that is typical of such low-energy emitters renders the phosphorescence extremely weak and short-lived at ambient temperature, and rapid ligand photodissociation also competes with radiative decay, especially in the heteroleptic complex. Electrochemical analysis illustrates the effect of biphe's stabilized vacant π* manifold, with multiple reversible reductions evident at much less negative potentials than those observed for [Ru(bpy) 3 ] 2+ . |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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