Lundin Natasha J, Walsh Penny J, Howell Sarah L, McGarvey John J, Blackman Allan G, Gordon Keith C
Department of Chemistry, MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, Dunedin, New Zealand.
Inorg Chem. 2005 May 16;44(10):3551-60. doi: 10.1021/ic050179k.
The ligands 11-bromodipyrido[3,2-a:2',3'-c]phenazine and ethyl dipyrido[3,2-a:2',3'-c]phenazine-11-carboxylate have been prepared and coordinated to ruthenium(II), rhenium(I), and copper(I) metal centers. The electronic effects of substitution of dipyrido[2,3-a:3',2'-c]phenazine (dppz) have been investigated by spectroscopy and electrochemistry, and some photophysical properties have been studied. The crystal structures of [Re(L)(CO)(3)Cl] (L = ethyl dipyrido[3,2-a:2',3'-c]phenazine-11-carboxylate or 11-bromodipyrido[3,2-a:2',3'-c]phenazine) are presented. Density functional theory calculations on the complexes show only small deviations in bond lengths and angles (most bonds within 0.02 Angstroms, most angles within 2 degrees) from the crystallographic data. Furthermore, the vibrational spectra of the strongest Raman and IR bands are predicted to within an average 6 cm(-1) for the complexes [Re(L)(CO)(3)Cl] and [Cu(L)(triphenylphosphine)(2)]BF(4) (in the 1000-1700 cm(-1) region). Spectroscopic and electrochemical evidence suggest that reduction of the complex causes structural changes across the entire dppz ligand. This is unusual as dppz-based ligands typically have electrochemical properties that suggest charge localization with reduction on the phenazine portion of the ligand. The excited-state lifetimes of the complexes have been measured, and they range from ca. 200 ns for the Ru(L)(2,2'-bipyridine)(2)(2) complexes to over 2 mus for Cu(11-bromodipyrido[3,2-a:2',3'-c]phenazine)(PPh(3))(2) at room temperature. The emission spectra suggest that the unusually long-lived excited states of the copper complexes result from metal-to-ligand charge transfer (MLCT) transitions as they are completely quenched in methanol. Electroluminescent films may be fabricated from these compounds; they show MLCT state emission even at low doping levels [<0.1% by weight in poly(vinylcarbazole) polymer matrix].
已制备出配体11-溴二吡啶并[3,2-a:2',3'-c]吩嗪和二吡啶并[3,2-a:2',3'-c]吩嗪-11-羧酸乙酯，并使其与钌（II）、铼（I）和铜（I）金属中心配位。通过光谱学和电化学方法研究了二吡啶并[2,3-a:3',2'-c]吩嗪（dppz）取代基的电子效应，并对一些光物理性质进行了研究。给出了[Re(L)(CO)(3)Cl]（L = 二吡啶并[3,2-a:2',3'-c]吩嗪-11-羧酸乙酯或11-溴二吡啶并[3,2-a:2',3'-c]吩嗪）的晶体结构。对这些配合物的密度泛函理论计算表明，键长和键角与晶体学数据相比仅有微小偏差（大多数键在0.02埃以内，大多数角度在2度以内）。此外，对于配合物[Re(L)(CO)(3)Cl]和[Cu(L)(三苯基膦)(2)]BF(4)（在1000 - 1700厘米⁻¹区域），最强拉曼和红外光谱带的振动光谱预测平均误差在6厘米⁻¹以内。光谱学和电化学证据表明，配合物的还原会导致整个dppz配体发生结构变化。这很不寻常，因为基于dppz的配体通常具有电化学性质，表明电荷定域在配体的吩嗪部分上。已测量了配合物的激发态寿命，在室温下，Ru(L)(2,2'-联吡啶)(2)(2)配合物的激发态寿命约为200纳秒，而Cu(11-溴二吡啶并[3,2-a:2',3'-c]吩嗪)(PPh(3))(2)的激发态寿命超过2微秒。发射光谱表明，铜配合物异常长寿命的激发态是由金属到配体的电荷转移（MLCT）跃迁引起的，因为它们在甲醇中会完全猝灭。可以由这些化合物制备电致发光薄膜；即使在低掺杂水平[在聚（乙烯咔唑）聚合物基质中重量百分比<0.1%]下，它们也显示出MLCT态发射。
