6-(1-Methylpyrrol-2-yl)-2,2'-bipyridine, 3, and 6-(selenophene-2-yl)-2,2'-bipyridine, 4, have been prepared and characterized in solution and by structural determinations. Copper(I) complexes [CuL(2)][PF(6)] in which L is 2,2'-bipyridine substituted in the 6-position by furyl, thienyl, N-methylpyrrolyl, selenopheneyl, methyl or phenyl, (L = 1-6) have been synthesized. The complexes have been characterized by electrospray mass spectrometry, and solution NMR and UV-VIS spectroscopies. The single crystal structures of [Cu(1)(2)][PF(6)], [Cu(2)(2)][PF(6)], [Cu(3)(2)][PF(6)], [Cu(5)(2)][PF(6)] and [Cu(6)(2)][PF(6)] have been determined. In those compounds containing an aromatic substituent attached to the bpy unit, the substituent is twisted with respect to the latter. In [Cu(3)(2)][PF(6)] and [Cu(5)(2)][PF(6)], this results in intra-cation π-stacking between ligands which is very efficient in [Cu(3)(2)](+) despite the steric requirements of the N-methyl substituents. Face-to-face stacking between the ligands in the [Cu(2)(2)](+) ion is achieved by complementary substituent twisting and elongation of one Cu-N bond, but there is no analogous intra-cation π-stacking in [Cu(1)(2)](+). Ligand exchange reactions between [CuL(2)][PF(6)] (L = 1-6) and TiO(2)-anchored ligands 7-10 (L' = 2,2'-bipyridine-based ligands with CO(2)H or PO(OH)(2) anchoring groups) have been applied to produce 24 surface-anchored heteroleptic copper(i) complexes, the formation of which has been evidenced by using MALDI-TOF mass spectrometry and thin layer solid state diffuse reflectance electronic absorption spectroscopy. The efficiencies of the complexes as dyes in DSCs have been measured, and the best efficiencies are observed for [CuLL'] with L' = 10 which contains phosphonate anchoring groups.
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.
The syntheses and properties of a series of eleven new [Ir(ppy)2(N^N)][PF6] complexes (Hppy = 2-phenylpyridine) are reported. The N^N ligands are based on 2,2-bipyridine (bpy), substituted in the 6- or 5-positions with groups that are structurally and electronically diverse. All but two of the N^N ligands incorporate an aromatic ring, designed to facilitate intra-cation face-to-face π-interactions between the N^N and one [ppy](-) ligand. Within the set of ligands, 6-(3-tolyl)-2,2'-bipyridine (5), 4,6-bis(4-nitrophenyl)-2,2'-bipyridine (9), and 4,6-bis(3,4,5-trimethoxyphenyl)-2,2'-bipyridine (10) are new and their characterization includes single crystal structures of 9, and two polymorphs of 10. A representative [Ir(ppy)2(N^O)](+) complex is also described. We report solution NMR spectroscopic, photophysical and electrochemical properties of the complexes, as well as representative solid-state structural data. The solution (1)H NMR spectroscopic data illustrate different dynamic processes involving the substituents attached to the bpy domain in the ligands. In degassed MeCN and at room temperature, the [Ir(ppy)2(N^N)][PF6] complexes are orange emitters with λ(em)max in the range 575 to 608 nm; however, quantum yields are very low. The most promising complexes were evaluated in light-emitting electrochemical cells leading to bright and stable devices with rather good external quantum efficiencies.
Alkaline earth metal derivatives of the diphosphanyldisiloxane O(SiiPr 2 PH 2 ) 2 (1) were obtained by reactions of 1 with MgBu 2 and M{N(SiMe 3 ) 2 } 2 (M = Ca, Sr, Ba), respectively. The metal complexes formed were characterised by elemental analysis, NMR spectroscopy, and IR spectroscopy as well as by single-crystal structure analysis. The solid-state structures depend on the metal ion involved. The magnesium derivative crystallizes from thf as a trimer and exhibits a six-mem-
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