Synthesis and Characterization of Neutral Luminescent Diphosphine Pyrrole- and Indole-Aldimine Copper(I) Complexes

Abstract

Heteroleptic copper(I) complexes of the types [Cu(N,N)(P,P)] and [Cu(N,O)(P,P)], where (P,P) = phosphine (PPh(3)) or diphosphine (dppb, DPEPHOS, XANTPHOS), (N,N) = pyrrole-2-phenylcarbaldimine, 2PyN: [Cu(2PyN)(PPh(3))(2)] (1), [Cu(2PyN) (dppb)] (2), [Cu(2PyN)(DPEPHOS)] (3), and [Cu(2PyN)(XANTPHOS)] (4), (N,N) = indole-2-phenylcarbaldimine, 2IndN: [Cu(2IndN)(DPEPHOS)] (8), and (N,O) = pyrrole-2-carboxaldehyde, 2PyO: [Cu(2PyO)(DPEPHOS)] (5), [Cu(2PyO)(XANTPHOS)] (6), or (N,O) = indole-2-carboxaldehyde, 2IndO: [Cu(2IndO)(DPEPHOS)] (7), were synthesized and characterized by multinuclear NMR spectroscopy, electronic absorption spectroscopy, fluorescence spectroscopy, and X-ray crystallography (1-3, 5-8). The complexes with aldimine ligands are thermally stable, and sublimation of 2-4 was possible at T = 230-250 °C under vacuum. All complexes exhibit long-lived emission in solution, in the solid state, and in frozen glasses. The excited states have been assigned as mixed intraligand and metal-to-ligand charge transfer (3)(MLCT + π-π*) transitions through analysis of the photophysical properties and DFT calculations on representative examples.

Synthesis, Structural Characterisation, and Spectroscopic Properties of Copper(I) Complexes and their Applications to Dye-Sensitised Solar Cells

“…[38,39] Broad absorption bands in the range of 325-450 nm with a molar extinction coefficient (e) of 4000-20000 M À1 cm À1 are attributed to dp-p* metal to ligand charge transfer (MLCT) absorptions. [40] The MLCT absorption maxima of these complexes, as reported previously, [41][42][43][44] are observed at slightly longer wavelengths. The lowest energy bands display that compounds 1 and 2 have the same absorbent peak at 345 nm, showing limited dependence on the identity of bridging ligands.…”

Two Neutral Copper(I) Complexes Bearing 2‐(4‐Nitrophenyl) Imidazole[4,5‐f]‐1,10‐Phenanthroline: Synthesis, Crystal Structure, and Luminescence Properties

“…The bond distances Cu(1)-(N3) and Cu(1)-N (4) are 2.283(2) and 2.207(1) Å, respectively, and bond distance Cu(1)-P(1) and Cu(1)-P(2) are 2.056(4) and 2.035 (5) Å, respectively, which are comparable to those observed in the related complexes. [22][23][24] The C N bond distances of imidazole ring range from 1.347(6) to 1.371(6) Å, which are similar to the distances of double C N bonds (1.354 (9)-1.388(9) Å) but are much longer than that (1.291 (8) complex, 25 confirming the deprotonation of NHPIP and the delocalized electronic structure of the NPIP anion.…”

Bis{2-[(phenylimino)methyl]-1H-pyrrol-1-ido}palladium(II)

“…For structure analyses of the free ligand N-[(1H-pyrrol-2-yl)methylene]aniline, see: Gomes et al (2010); Crestani et al (2011). For the structure of a related nickel complex of the same imine ligand and an additional bipyridine ligand, see: Castro et al (1992).…”

“…E68, m1567 [doi:10.1107/S1600536812048143] Bis{2-[(phenylimino)methyl]-1H-pyrrol-1-ido}palladium(II) Wolfgang Imhof Comment In the course of a project related to the supramolecular structures of square planar nickel and palladium complexes of pyrrole-2-carbaldehyde based Schiff base ligands in comparison with the structures of the free ligands the molecular structure of the title compound was determined. The free ligands form inversion dimers via N-H···N hydrogen bondsbetween the pyrrole NH function and the imine nitrogen atom of a neighbouring molecule(Crestani et al, 2011;Gomes et al 2010).…”