Design And Synthesis Of Monovalent Copper Phosphorescent Complexes Structure And Properties

Cu（I） complexes, as a kind of photo-funetional materials，had played an importantrole.These complexes, because of variety of struetures, low cost, novel photochemical andphotophisieal properties, had attracted more attention in many fields, such as optoelectronicdevices, molecular devices, solar energy conversion, optical sensor, nonlinear optics and so on.Through molecular structures and luminescence prediction, we cleverly designed N-heterocyclechelating ligands. A series of Cu（I） complexes were synthesized with different substituted.Their molecular struetures were determined by X-ray diffraction and HNMR. The research ontheir photochemical and photophisieal properties, especially the attribution of exeited states,had been carried out by spectra of UV-Vis, spectra of emission and spectra of excitation,andobtained some interesting results:1．We designed and synthesized a new N-heterocycle chelating ligand such as6-cyano-2,2′-bipyridine （cbpy） and three new mono-copper（I） complexes [Cu（cbpy）（PPh₃）I]（1）、[Cu（cbpy）（PPh₃）Br]（2） and [Cu（cbpy）（PPh₃）2]（ClO₄）（3） were synthesized. Their X-ray structure analysisindicates that the tetrahedral coordination geometry of copper（I） atom Different to the stackingmanners of two neighboring cbpy ligands in1and2, the π–π stacking of3only occurs betweenthe pyridyl rings of two adjacent cbpy ligands. The interplanar distance of1-3is approximately3.48,3.62,3.48, respectly; suggesting that a weak π–π interaction is likely operatingbetween intermolecular two cbpy ligands.The emissive excited states of the halide complexes1and2were perhaps best regarded as the metal-to-ligand charge transfer （MLCT） excited stateswith some mixing of the halide-to-ligand charge transfer （XLCT） character. The emissive excitedstates of the complexes3is reasonably assigned to an MLCT excited state.2． We designed and synthesized a new N-heterocycle chelating ligand such as2-（2-benzimidazolyl）-6-methylpyridine （Hbmp） and three new mono-copper（I） halide complexesCu（Hbmp）（PPh₃）I （4）、Cu（Hbmp）（PPh₃）Br （5） and Cu（Hbmp）（PPh₃）Cl （6） were synthesized.Their X-ray structure analysis indicates that the tetrahedral coordination geometry of copper（I）atom. It is interesting to note that only the Cu-Npyridyldistance depends on the halide ancillaryligand, whereas the Cu-Nimidazolylond length is largely identical in1–3, implying that the halideprobably has certain effect on only the pyridyl unit, and not the entire Hbmp ligand. Theinterplanar separations are in the range3.2–3.5for1–3, indicating a weak aromatic π–πinteraction between two neighboring Hbmp ligands. Moreover, the weak intermolecular N-H Xhydrogen-bonding interactions are also observed in1–3with the NH X distances. Combinedwith DFT calculating results, the emissive excited states of the halide complexes4-6wereperhaps best regarded as the metal-to-ligand charge-transfer （MLCT） excited states with somemixing of the ligand-to-ligand charge transfer（LLCT）. 3. We designed and synthesized three new N-heterocycle chelating ligands with NHfunction base such as5-tert-butyl-3-（pyridine-2-yl）-1H-1,2,4-triazole （bptzH）,5-tert-butyl-3-（6-methylpyridine-2-yl）-1H-1,2,4-triazole（bmptzH） and,5-trifluoromethyl-3-（pyridine-2-yl）-1,2,4-triazole（fptzH） four new mono-copper（I） halide complexes Cu（bptzH）（PPh₃）I （7）、Cu（bptzH）（PPh₃）Br （8）、Cu（bptzH）（PPh₃）Cl （9） and Cu（bmptzH）（PPh₃）I （10） and four newmono-copper（I） phosphine complexes [Cu（bptzH）（PPh₃）₂][ClO₄]（11）、[Cu（fptzH）（PPh₃）₂][ClO₄]（12）、Cu（fptz）（PPh₃）2（13） and [Cu（bptzH）（dppe）][ClO₄]（14） were synthesized. We havediscussed the influence of copper（I） complexes with different substituted halide, phosphineligand and alkaline condition. Their X-ray structure analysis indicates that the tetrahedralcoordination geometry of copper（I） atom. It is interesting to note that the Cu-Npyridyldistanceand Cu-Nimidazolylbond length depends on the halide ancillary ligand in7–9, implying that thehalide probably has certain effect on the entire ligand, and not the the pyridyl unit. Thecomplexes13has two distinctive Cu–N distances, the Cu–Ntriazolyllength of2.016（2） beingobviously shorter than its Cu–Npyridyldistance of2.207（2）. The molecular structure of13compared to12upon ring inversion motion of the coordinated1,2,4-triazole mediated byNH-deprotonation under basic medium. It is reflects the stronger bonding ability of the N atomof1,2,4-triazole with Cu（I） center versus the pyridine and suggestive of the significantinfluence of the anionic1,2,4-triazolate chelate resulting from the NH-deprotonation. Theemissions of the halide complexes7-10were perhaps best regarded as the metal-to-ligandcharge-transfer （MLCT） excited states with some mixing of the ligand-to-ligand chargetransfer（LLCT）. The emissions of the complexes complexes11-14were perhaps best regardedas the metal-to-ligand charge-transfer （MLCT） excited states with some mixing of theligand-to-ligand charge transfer（LLCT）.