Phosphorescent, liquid-crystalline complexes of platinum(II): influence of the β-diketonate co-ligand on mesomorphism and emission properties

被引:54
作者
Spencer, Matthew [1 ]
Santoro, Amedeo [1 ]
Freeman, Gemma R. [2 ]
Diez, Alvaro [1 ]
Murray, Paul R. [3 ]
Torroba, Javier [1 ]
Whitwood, Adrian C. [1 ]
Yellowlees, Lesley J. [3 ]
Williams, J. A. Gareth [2 ]
Bruce, Duncan W. [1 ]
机构
[1] Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England
[2] Univ Durham, Dept Chem, Univ Sci Labs, Durham DH1 3LE, England
[3] Univ Edinburgh, Sch Chem, Edinburgh EH9 3JJ, Midlothian, Scotland
基金
英国工程与自然科学研究理事会;
关键词
CYCLOMETALATED PLATINUM(II); LUMINESCENCE; METALLOMESOGENS; TERDENTATE; ELECTROPHOSPHORESCENCE; IRIDIUM(III); PHOTOPHYSICS; EFFICIENCY; DINUCLEAR;
D O I
10.1039/c2dt31525d
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Two series of rod-like ortho-platinated complexes bound to a range of beta-diketonate co-ligands are reported of the form [Pt(N boolean AND C)(O boolean AND O)]. The liquid crystal and luminescent properties are influenced through the introduction of different beta-diketonates (O boolean AND O) as well as through the presence of a fused cyclopentene ring on the N boolean AND C-coordinated 2-phenylpyridine ligand. For metal complexes, smectic phases are dominant but no mesomorphism is exhibited when the beta-diketonate is hexafluorinated acetylacetonate (1,1,1-5,5,5-hexafluoro-2,4-pentandione). The introduction of an unsymmetrical trifluoroacetyl acetonate (1,1,1-trifluoro-2,4-pentandione) ligand is particularly interesting due to the discovery of the beta-diketonate as a dynamic system that readily isomerises to a 1 : 1 ratio under thermal conditions, from an initial ratio of 3 : 1 formed during the synthesis. As expected, the presence of the 3,5-heptanedionato co-ligand decreases the transition temperatures due to the introduction of a larger lateral substituent. Unfortunately complexes based on 2-phenylpyridine ligands with a fused cyclopentene ring are, with one exception, not mesomorphic. With the exception of the hexafluoroacetyl acetonate complexes, the materials are brightly luminescent and have excited state lifetimes between 13 and 30 mu s with emission quantum efficiencies exceeding 0.5, with one as high as 0.7. A time-dependent density functional theory (TD-DFT) study suggests that the lack of emission from the hexafluoroacetyl acetonate complexes may be associated with large structural distortion upon formation of the excited state, as well as to poorer overlap of orbitals leading to a lower radiative rate constant. The same analysis provides an explanation for the apparently quite different emission efficiencies of the two isomers of the trifluoroacetyl acetonate complexes.
引用
收藏
页码:14244 / 14256
页数:13
相关论文
共 62 条
[1]  
Altshuler S.A., 1964, ELECT PARAMAGNETIC R
[2]  
[Anonymous], SAINT INT SOFTW BRUK
[3]  
[Anonymous], SMART CONTR SOFTW BR
[4]   Gold liquid crystals displaying luminescence in the mesophase and short F...F interactions in the solid state [J].
Bayón, R ;
Coco, S ;
Espinet, P .
CHEMISTRY-A EUROPEAN JOURNAL, 2005, 11 (04) :1079-1085
[5]  
Binnemans K., 2010, In Physical properties of metallomesogens, P61, DOI 10.1002/9780470686058.ch2
[6]   Luminescence of metallomesogens in the liquid crystal state [J].
Binnemans, Koen .
JOURNAL OF MATERIALS CHEMISTRY, 2009, 19 (04) :448-453
[7]   Synthesis and characterization of phosphorescent cyclometalated platinum complexes [J].
Brooks, J ;
Babayan, Y ;
Lamansky, S ;
Djurovich, PI ;
Tsyba, I ;
Bau, R ;
Thompson, ME .
INORGANIC CHEMISTRY, 2002, 41 (12) :3055-3066
[8]   PHOTOLYTIC GENERATION OF RADICAL-ANIONS AND DIANIONS AND GROUP IVB ORGANO-METALLIC ADDUCTS OF BETA-DIKETONES - AN ELECTRON-SPIN RESONANCE STUDY ON THE EFFECTS OF FLUORINE SUBSTITUTION AND CROWN ETHERS [J].
CHEN, KS ;
WAN, JKS .
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1982, (04) :419-423
[9]   Luminescence and photoconductivity in mononuclear ortho-platinated metallomesogens [J].
Damm, C ;
Israel, G ;
Hegmann, T ;
Tschierske, C .
JOURNAL OF MATERIALS CHEMISTRY, 2006, 16 (19) :1808-1816
[10]   Cyclometalated Platinum(II) Complexes of N∧C∧N-Coordinating, Terdentate Ligands: the Contrasting Influence of Pyrazolyl and Pyridyl Rings on Luminescence [J].
Develay, Stephanie ;
Blackburn, Octavia ;
Thompson, Amber L. ;
Williams, J. A. Gareth .
INORGANIC CHEMISTRY, 2008, 47 (23) :11129-11142