Introducing intramolecular, interligand arene–alkynyl π-interactions into heteroleptic [Cu(N^N)(P^P)]+ complexes?

CrystEngComm Pub Date: 2023-05-01 DOI: 10.1039/D3CE00355H

Abstract

The synthesis and characterization of six new heteroleptic copper(I) compounds incorporating wide bite-angle bisphosphanes (POP = [oxydi(2,1-phenylene)]bis(diphenylphosphane), xantphos = (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)) combined with 6,6′-di(but-3-yn-1-yl)-2,2′-bipyridine (1), 6-(but-3-yn-1-yl)-6′-methyl-2,2′-bipyridine (2) or 6-(but-3-yn-1-yl)-2,2′-bipyridine (3) are reported. The single-crystal structures of [Cu(1)(POP)][PF6], [Cu(1)(xantphos)][PF6], [Cu(3)(POP)][PF6] and [Cu(3)(xantphos)][PF6] have been determined and confirm distorted tetrahedral copper(I) centres. In the solid state, the compounds are yellow or green emitters (λemmax = 530–573 nm). The highest solid-state photoluminescence quantum yields (PLQYs) were observed for [Cu(1)(xantphos)][PF6] (46%) and [Cu(1)(POP)][PF6] (41%). A combination of face-to-face arene?arene π-stacking interactions and C[triple bond, length as m-dash]C?πarene interactions protects the Cu atom in each structurally characterized complex. The C[triple bond, length as m-dash]C?πarene interactions are characterized by a near parallel alignment of the C[triple bond, length as m-dash]CH unit over an arene ring, and Calkyne?arenecentroid distances lie in the range of 3.74 to 4.16 ?, and C[triple bond, length as m-dash]Ccentroid?arenecentroid distances lie between 3.86 and 4.09 ?. These distances fall well within the ranges for related interactions for compounds in the Cambridge Structural Database, and data for these interactions are presented.

Graphical abstract: Introducing intramolecular, interligand arene–alkynyl π-interactions into heteroleptic [Cu(N^N)(P^P)]+ complexes
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