Heteroleptic [Cu(P^P)(N^N)][PF6] Compounds with Isomeric Dibromo-1,10-Phenanthroline Ligands

Abstract

A series of [Cu(P^P)(N^N)][PF6] compounds are reported in which N^N is 2,9-dibromo-1,10-phenanthroline (2,9-Br2phen), 3,8-dibromo-1,10-phenanthroline (3,8-Br2phen) or 4,7-dibromo-1,10-phenanthroline (4,7-Br2phen) and P^P is bis(2-(diphenylphosphano)phenyl)ether (POP) or 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene (xantphos). The compounds were characterized by solution multinuclear NMR spectroscopy, mass spectrometry and a single-crystal X-ray analysis. Each compound underwent a partially reversible or irreversible copper-centred oxidation, the highest potential being for 2,9-Br2phen-containing compounds. In solution, the compounds are weak yellow or orange emitters, whereas powdered samples exhibit yellow emissions with photoluminescence quantum yields of up to 45% for [Cu(xantphos)(2,9-Br2phen)][PF6] with an excited state lifetime τ1/2 = 9.9 μs. Values of λemmax for [Cu(POP)(2,9-Br2phen)][PF6] and [Cu(xantphos)(2,9-Br2phen)][PF6] are blue-shifted with respect to compounds with the 3,8-and 4,7-isomers, both in solution and in the solid state.

TADF: Enabling luminescent copper(i) coordination compounds for light-emitting electrochemical cells

“…The photophysical properties of the complexes containing 2,9-phen are enhanced with respect to analogues containing 3,8-or 4,7-dibromo-1,10phenanthrolines. 111 More detailed investigations of these compounds have not been carried out. This journal is © The Royal Society of Chemistry 20xx…”

The Heteroleptic Cu(I) Photosensitizer‐Containing 3,8‐Disubstituted Phenanthroline: Synthesis, Photophysical Properties and Photocatalytic Hydrogen Evolution from Water

“…[ 12 ] The [Cu(xantphos)(3,8‐Br 2 phen)][PF 6 ] compound exhibited yellow emission with photoluminescence quantum yield of up to 21 % for it with an excited state lifetime τ 1/2 = 8.4 μs. [ 13 ] Therefore, the photocatalytic activity of [Cu(PˆP)(NˆN)][PF 6 ] compound should be improved by modifying the 3,8‐sites of phenanthroline. In view of this, whether this regularity can be confirmed in 3,8‐sites of phenanthroline is of interest to us.…”

The surprising effects of sulfur: achieving long excited-state lifetimes in heteroleptic copper(i) emitters

“…The data in Table 2 are not clear-cut. However, considering the differences of E 1/2 ox of the [Cu(P^P)((MeO) 2 phen)] + and [Cu(P^P)((MeS) 2 phen)] + complexes, as well as the data previously reported on [Cu(P^P)(Br 2 phen)] + , 34 it can be concluded that the electron-donating or withdrawing effects of a specific substituent has a significant influence on the Cu + /Cu 2+ oxidation potentials.…”

“…2,9-Br 2 phen was prepared following a literature route 33 and the NMR spectroscopic data matched those reported. 33,34 All other chemicals were purchased from Sigma Aldrich. Microwave reactions were carried out in a Biotage Initiator+ microwave reactor.…”