Dual Emission from Rhenium(I) Complexes Induced by an Interligand Aromatic Interaction
Dual Emission from Rhenium(I) Complexes Induced by an Interligand Aromatic Interaction
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DOI：
10.1002/chem.201102698
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发表时间：
2012-03-01
影响因子：
4.3
通讯作者：
Ishitani, Osamu
中科院分区：
文献类型：
--
作者：
Morimoto, Tatsuki;Ito, Megumi;Ishitani, Osamu
利用光化学配体取代反应合成了一系列双（I）二亚胺配合物cis，trans-Re（dmb）（CO）2（PR 1 R2 R3）（PR 4 R5 R6）]+（dmb= 4，4 '-二甲基-2，2'-联吡啶，Rn=苯基或烷基），每个配合物带有两个不同数目苯基的膦配体。不仅在晶体中，而且在溶液中的结构特征的详细研究表明，苯基基团的数量是控制膦配体的旋转构象的关键因素，这反过来又决定了芳香族二亚胺配体和苯基基团之间的pp相互作用的程度。pp相互作用强烈地影响电化学和电子物理性质：1）Re络合物的氧化能力变强，2）激发态的寿命变长，3）1 MLCT吸收带和相应3 MLCT激发态发射之间的Stokes位移变小。特别是二苯基膦和三苯基膦配体对性能的影响比单苯基膦配体大得多。双发射观察到从不同的旋转构象的络合物与中间数量的苯基膦配体。
A series of rhenium(I) diimine complexes cis,trans-[Re(dmb)(CO)2(PR1R2R3)(PR4R5R6)]+ (dmb=4,4'-dimethyl-2,2'-bipyridine, Rn=phenyl or alkyl), each of which bears two phosphine ligands with various numbers of phenyl groups, has been synthesized by using the photochemical ligand-substitution reaction. Detailed studies of the structural features, not only in the crystal but also in solution, indicate that the number of phenyl groups is a crucial factor in controlling the rotational conformation of the phosphine ligands, which in turn determines the extent of the pp interaction between the aromatic diimine ligand and the phenyl group(s). The pp interaction strongly affected both electrochemical and photophysical properties: 1) the oxidation power of the Re complex became stronger, 2) the lifetime of the excited state became longer, and 3) the Stokes shift between the 1MLCT absorption band and emission from the corresponding 3MLCT excited state became smaller. In particular, the diphenyl and triphenyl phosphine had much greater influence on the properties than the monophenyl phosphine ligand. Dual emission was observed from the different rotational conformers of the complexes with an intermediate number of phenyl groups in the phosphine ligands.