Several dinuclear
terphenyl phosphine copper(I) halide complexes
of composition [CuX(PR2Ar′)]2 (X = Cl,
Br, I; R = hydrocarbyl, Ar′ = 2,6-diarylterphenyl radical), 1–5, have been isolated from the reaction
of CuX with 1 equiv of the phosphine ligand. Most of them have been
characterized by X-ray diffraction studies in the solid state, thus
allowing comparative discussions of different structural parameters,
namely, Cu···Cu and Cu···Aryl separations,
conformations adopted by coordinated phosphines, and planarity of
the Cu2X2 cores. Centrosymmetric complexes [CuI(PMe2ArXyl2)]2, 1c, and [CuI(PEt2ArMes2)]2, 3c, despite
their similar structures, show very distinct photoluminescence (PL)
in powder form at room temperature. The photophysical behavior of
these compounds in liquid solution, solid–solid Zeonex solution
and powder samples at room temperature and 77 K have been investigated
and supported by DFT calculation. Identification of vibronic coupling
modes, done by group theory calculations and the technique of projection
operators, shows that the manifestation of these modes is conditioned
by crystal packing. Complexes [CuI(PMe2ArXyl2)]2, 1c, and [CuI(PEt2ArMes2)]2, 3c, display remarkable activity in copper-catalyzed
azide–alkyne cycloaddition reactions involving preformed and
in situ-made azides. Reactions are performed in H2O, under
aerobic conditions, with low catalyst loadings and tolerate the use
of iodoalkynes as substrates.
