Synthesis,Structure and Photophysical Properties of a New Neutral Copper (Ⅰ) Complex

doi:10.7517/j.issn.1674-0475.2018.01.006

Abstract

Abstract: A new neutral heteroleptic copper(Ⅰ) complex supported by diimine and diphosphine ligands was successfully synthesized and characterized by ¹HNMR, ¹³CNMR, ³¹PNMR and single-crystal X-ray diffraction. This complex adopts a typical distorted tetrahedral configuration and shows high stability in solid state. Theory calculation results show the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the complex have little metal character, and the lowest energy electronic transition is mainly ligand-to-ligand charge transfer (LLCT) transition. This complex shows intense emission with relative high efficiency and long lifetime in solid state, and analysis of the photophysical data recorded at 298 K and 77 K indicates the emission is phosphorescence stemming from triplet state.

Key words: copper(Ⅰ)complex, crystal structure, phosphorescence, OLEDs

SUN Xiaojuan, WANG Zhiqiang, ZHANG Zhiqiang, XU Liancai. Synthesis,Structure and Photophysical Properties of a New Neutral Copper (Ⅰ) Complex[J]. Imaging Science and Photochemistry, 2018, 36(1): 64-72.

References

[1] Xu H, Chen R,Sun Q. Recent progress in metal-organic complexes for optoelectronic applications[J]. Chemical Society Reviews, 2014,43(10):3259-3302.
[2] Volz D,Wallesch M, Fléchon C. From iridium and platinum to copper and carbon:new avenues for more sustainability in organic light-emitting diodes[J]. Green Chemistry, 2015,17(4):1988-2011.
[3] Chi Y, Tong B, Chou P T. Metal complexes with pyridylazolates:design, preparation and applications[J]. Coordination Chemistry Reviews, 2014,281(1):1-25.
[4] Ma Y, Che C M, Chao H Y, Zhou X, Chan W H, Shen J. High luminescence gold(Ⅰ) and copper(Ⅰ) complexes with a triplet excited state for use in light-emitting diodes[J]. Advanced Materials, 1999,11(10):852-857.
[5] Cuttell D G, Kuang S M, Fanwick P E. Simple Cu(Ⅰ) complexes with unprecedented excited-state lifetimes[J]. Journal of the American Chemical Society, 2002,124(1):6-7.
[6] Zhang Q, Zhou Q, Cheng Y, Wang L, Ma D, Jing X. Highly efficient green phosphorescent organic light-emitting diodes based on Cu^I complexes[J]. Advanced Materials, 2004,16(5):432-436.
[7] Vorontsov Ⅱ, Graber T, Kovalevsky A Y. Capturing and analyzing the excited-state structure of a Cu(Ⅰ) phenanthroline complex by time-resolved diffraction and theoretical calculations[J]. Journal of the American Chemical Society, 2009,131(18):6566-6573.
[8] Wada A, Zhang Q, Yasuda T. Efficient luminescence from a copper(Ⅰ) complex doped in organic light-emitting diodes by suppressing C-H vibrational quenching[J]. Chemical Communications, 2012,48(43):5340-5342.
[9] Hsu C W, Lin C C, Chung M W. Systematic investigation of the metal-structure-photophysics relationship of emissive d¹⁰-complexes of group 11 elements:the prospect of application in organic light emitting devices[J]. Journal of the American Chemical Society, 2011,133(31):12085-12099.
[10] Hashimoto M, Igawa S, Yashima M. Highly efficient green organic light-emitting diodes containing luminescent three-coordinate copper(Ⅰ) complexes[J]. Journal of the American Chemical Society, 2011,133(27):10348-10351.
[11] Gneuß T, Leitl M J, Finger L H, Rau N. A new class of luminescent Cu(Ⅰ) complexes with tripodal ligands-TADF emitters for the yellow to red color range[J]. Dalton Transactions, 2015,44(18):8506-8520.
[12] Leitl M J, Krylova V A, Djurovich P I, Thompson M E,Yersin H. Phosphorescence versus thermally activated delayed fluorescence. Controlling singlet-triplet splitting in brightly emitting and sublimable Cu(Ⅰ) compounds[J]. Journal of the American Chemical Society, 2014,136(45):16032-16038.
[13] Hofbeck T, Monkowius U, Yersin H. Highly efficient luminescence of Cu(Ⅰ) compounds:thermally activated delayed fluorescence combined with short-lived phosphorescence[J]. Journal of the American Chemical Society, 2015,137(1):399-404.
[14] Deaton J C, Switalski S C, Kondakov D Y. E-type delayed fluorescence of a phosphine-supported Cu₂(μ-NAr₂)₂ diamond core:harvesting singlet and triplet excitons in OLEDs[J]. Journal of the American Chemical Society, 2010,132(27):9499-9508.
[15] Gneuß T, Leitl M J, Finger L H, Yersin H, Sundermeyer J. A new class of deep-blue emitting Cu(Ⅰ) compounds-effects of counter ions on the emission behavior[J]. Dalton Transactions, 2015,44(46):20045-20055.
[16] Coppens P, Sokolow J, Trzop E. On the biexponential decay of the photoluminescence of the two crystallographically-independent molecules in crystals of[Cu(Ⅰ)(phen)(PPh₃)₂] [BF₄] [J]. Journal of Physics Chemistry Letters, 2013,4(4):579-582.
[17] Wang Z, Zheng C, Wang W, Xu C, Ji B, Zhang X. Synthesis, structure, and photophysical properties of two four-coordinate CuI-NHC complexes with efficient delayed fluorescence[J]. Inorganic Chemistry, 2016,55(5):2157-2164.
[18] Liang D, Chen X L, Liao J Z, Hu J Y, Jia J H, Lu C Z. Highly efficient cuprous complexes with thermally activated delayed fluorescence for solution-processed organic light-emitting devices[J]. Inorganic Chemistry, 2016,55(15):7467-7475.
[19] Elie M, Sguerra F, Meo F D. Designing NHC-copper(Ⅰ) dipyridylamine complexes for blue light-emitting electrochemical cells[J]. ACS Applied Materials & Interfaces, 2016,8(23):14678-14691.
[20] Chai W, Hong M, Song L. Three reversible polymorphic copper(Ⅰ) complexes triggered by ligand conformation:insights into polymorphic crystal habit and luminescent properties[J]. Inorganic Chemistry, 2015,54(9):4200-4207.
[21] Marion R, Sguerra F, Meo F D. NHC copper(Ⅰ) complexes bearing dipyridylamine ligands:synthesis, structural, and photoluminescent studies[J]. Inorganic Chemistry, 2014,53(17):9181-9191.
[22] Femoni C, Muzzioli S, Palazzi A. New tetrazole-based Cu(Ⅰ) homo-and heteroleptic complexes with various P^∧P ligands:synthesis, characterization, redox and photophysical properties[J]. Dalton Transactions, 2013,42(4):997-1010.
[23] Czerwieniec R, Kowalski K, Yersin H. Highly efficient thermally activated fluorescence of a new rigid Cu(Ⅰ) complex[Cu(dmp)(phanephos)]⁺[J]. Dalton Transactions, 2013,42(27):9826-9830.
[24] Krylova V A, Djurovich P I, Whited M T, Thompson M E. Synthesis and characterization of phosphorescent three-coordinate Cu(Ⅰ)-NHC complexes[J]. Chemical Communications, 2010,46(36):6696-6698.
[25] Krylova V A, Djurovich P I, Aronson J W. Structural and photophysical studies of phosphorescent three-coordinate copper(Ⅰ) complexes supported by an N-heterocyclic carbene ligand[J]. Organometallics, 2012,31(22):7983-7993.
[26] Krylova V A, Djurovich P I, Conley B L. Control of emission colour with N-heterocyclic carbene (NHC) ligands in phosphorescent three-coordinate Cu(Ⅰ) complexes[J]. Chemical Communications, 2014,50(54):7176-7179.
[27] Kang L, Chen J, Teng T, Chen X L,Yu R, Lu C Z. Experimental and theoretical studies of highly emissive dinuclear Cu(Ⅰ) halide complexes with delayed fluorescence[J]. Dalton Transactions, 2015,44(30):11649-11659.
[28] Okano Y, Ohara H, Kobayashi A, Yoshida M, Kato M. Systematic introduction of aromatic rings to diphosphine ligands for emission color tuning of dinuclear copper(Ⅰ) iodide complexes[J]. Inorganic Chemistry, 2016,55(11):5227-5236.
[29] Czerwieniec R, Yersin H. Diversity of copper(Ⅰ) complexes showing thermally activated delayed fluorescence:basic photophysical analysis[J]. Inorganic Chemistry, 2015,54(9):4322-4327.
[30] Igawa S, Hashimoto M, Kawata I. Highly efficient green organic light-emitting diodes containing luminescent tetrahedral copper(Ⅰ) complexes[J]. Journal of Materials Chemistry C, 2013,1(3):542-551.
[31] Zhang L, Li B, Su Z. Realization of high-energy emission from[Cu(N-N)(P-P)]⁺ complexes for organic light-emitting diode applications[J]. The Journal of Physical Che-mistry C, 2009,113(31):13968-13973.
[32] Jia W L, McCormick T, Tao Y, Lu J P, Wang S. New phosphorescent polynuclear Cu(Ⅰ) compounds based on linearand star-shaped 2-(2'-Pyridyl)benzimidazolyl derivatives:syntheses, structures, luminescence, and electroluminescence[J]. Inorganic Chemistry, 2005,44(16):5706-5712.
[33] Si Z, Li J, Li B, Liu S, Li W. High light electroluminescence of novel Cu(Ⅰ) complexes[J]. Journal of Luminescence, 2009,129(3):181-186.
[34] Zhang D. Novel green-emitting copper(Ⅰ) complexes with electron donors incorporated ligands:synthesis, photophysical properties, and electroluminescence performances[J]. Journal of Luminescence, 2010,130(8):1419-1424.
[35] Min J, Zhang Q, Sun W, Cheng Y, Wang L. Neutral copper(Ⅰ) phosphorescent complexes from their ionic counterparts with 2-(2'-quinolyl)benzimidazole and phosphine mixed ligands[J]. Dalton Transactions, 2011,40(3):686-693.
[36] Bergmann L, Friendrichs J, Mydlak M. Outstanding luminescence from neutral copper(Ⅰ) complexes with pyridyl-tetrazolate and phosphine ligands[J]. Chemical Communications, 2013,49(58):6501-6503.
[37] Wang R, Xiao J C, Twamley B, Shreeve J M. Efficient heck reactions catalyzed by a highly recyclable palladium(Ⅱ) complex of a pyridyl-functionalized imidazolium-based ionic liquid[J]. Organic & Biomolecular Chemistry, 2007,5(4) 671-678.
[38] Scaltrito D V, Thompson D W, O'Callaghan J A, Meyer G J. MLCT excited states of cuprous bis-phenanthroline coordination compounds[J]. Coordination Chemistry Reviews, 2000,208(1):243-266.
[39] Armaroli N. Photoactive mono-and polynuclear Cu(Ⅰ)-phenanthrolines. A viable alternative to Ru(Ⅱ)-polypyridines[J]. Chemical Society Reviews, 2001,30(2):113-124.