Restricting the geometrical relaxation in four-coordinate copper(i) complexes using face-to-face and edge-to-face π-interactions

Abstract

A series of [Cu(N,N)(P,P)] + , [Cu(N,N)(P,S)] + , [Cu(N,N) 2 ] + and [Cu(P,S) 2 ] + complexes incorporating the ligands 2,2 0 -bipyridine, 1,10-phenanthroline, 1,2-bis(diphenylphosphino)ethane, bis(2-(diphenylphosphino)phenyl)ether (1), 2-diphenylphosphinothioanisole (3) and 2-methyl-6 0 -phenyl-2,2 0 -bipyridine (4) has been synthesized and structurally characterized. We have assessed the degree of distortion of two bidentate ligands away from an ideal tetrahedral arrangement about the copper(I) ion using the White model. The greatest distortion along a pathway towards square planar coordination is observed in [Cu(4) 2 ][PF 6 ] and is a result of intra-cation p-stacking between phenyl and bpy domains. Each of the complexes which contain the P,S-chelating ligand 3 exhibits significant 'rocking' or 'wagging' distortions which are associated with intra-cation CH methyl /p interactions. The extent of this distortion can also be assessed using a less rigorous approach by measuring the S-Cu-X and P-Cu-X angles where the S and P atoms belong to ligand 3, and X is the midpoint of the backbone of the second ligand. [Cu(3) 2 ][PF 6 ] and [Cu(1)(3)][PF 6 ] exhibit embraces between the phenyl substituents that result in the copper(I) ion being sterically protected, and the room temperature 1 H NMR solution spectrum of [Cu(1)(3)][PF 6 ] reveals hindered rotation of the phenyl rings of ligand.Scheme 1 Structures of ligands with numbering scheme used for NMR spectroscopic assignments; unsubstituted Ph rings are labelled B in 2, 3 and dppe, and D in 1.

Long-lived and oxygen-responsive photoluminescence in the solid state of copper(i) complexes bearing fluorinated diphosphine and bipyridine ligands

“…Since the pentafluorophenyl group is generally one of the strongest electron withdrawing groups, 35,36 the luminescence behaviors of dfppe complexes are expected to be drastically changed from those of dppe complexes. Here, we investigate the photophysics of a family of the copper(I) complexes of [Cu(bpy)(dppe)]PF 6 (1⋅PF 6 , bpy = 2,2′-bipyridine, dppe = 1,2-bis(diphenylphosphino)ethane) 26 and newly synthesized six complexes, [Cu(4dmbpy)(dppe)]PF 6 (2⋅PF 6 , 4dmbpy = 4,4′-dimethyl-2,2′-bipyridine),…”

Neutral copper(i) dipyrrin complexes and their use as sensitizers in dye-sensitized solar cells

“…Yield: 46 45 [Cu(CH 3 CN) 4 ][BF 4 ] (28 mg, 0.09 mmol), HL2 (35 mg, 0.09 mmol) and 1M NaOH (0.09 mL) were added to degassed acetone (10 mL) and stirred at room temperature, under nitrogen, for 15 mins. Tmbpy (19 mg, 0.09 mmol) was added and the solution 50 was stirred for a further 45 mins. The mixture was filtered and the solvent was removed under reduced pressure.…”

“…In the case of 4 and 5, only NMR characterisation was possible due to difficulties in obtaining sufficient yield (4) and residual ligand impurities (5). Clearly, complex formation with the new ligand L3 has proven difficult, however we include 4 and 5 in the study 50 as they have the greatest relevance to DSSC application and the in situ dye assembly described later.…”

“…31 Teets et al reported the first neutral Cu(I) complex of the related azadipyrromethene complex, 34 which was weakly luminescent at room temperature. Given the emerging importance of Cu(I) polypyridyl 50 complexes in optoelectronic fields, such species that also incorporate a dipyrrin ligand would form an attractive and tunable family of functional dyes. Accordingly, this work focuses on the synthesis and analysis of the first examples of copper(I) complexes that feature a dipyrrin ligand and a functionalised 2,2'-55 bipyridyl ligand.…”

Biomimetic Catalysts for Oxidation of Veratryl Alcohol, a Lignin Model Compound

“…The superstructure of 4 involves associations via a combination of π-aryl offset interactions [20] and hydrogen bonds between capping water molecules and both phenoxy and methoxy oxygen atoms of the neighboring Schiff base ligand, forming μ-aquo dimeric units. These hydrogen bonds are charge-assisted, that is, the hydrogen bond donor and/or acceptor carry positive and negative ionic charges, respectively, and hence are rather strong and short.…”