Department of Chemistry, University of Eastern Finland, Joensuu, 80101, Finland.
Inorg Chem. 2011 Mar 21;50(6):2395-403. doi: 10.1021/ic102204h. Epub 2011 Feb 8.
Reactions between the diphosphino-gold cationic complexes Au(2)(PPh(2)-C(2)-(C(6)H(4))(n)-C(2)-PPh(2))(2) (n = 0, 1, 2, 3) and polymeric acetylides (AuC(2)Ph)(n) and (AgC(2)Ph)(n) lead to the formation of a new family of heterometallic clusters with the general formula Au(8+2n)Ag(6+2n)(C(2)Ph)(8+4n)(PPh(2)C(2)(C(6)H(4))(n)C(2)PPh(2))(2), n = 0 (1), 1 (2), 2 (3), 3 (4). Compounds 1-4 were characterized in detail by NMR and ESI-MS spectroscopy. Complex 1 (n = 0) crystallizes in two forms (orange (1a) and yellow (1b)), one of which (1a) has been analyzed by X-ray crystallography. The luminescence behavior of 1-4 has been studied. Compounds 2 and 3 exhibited orange-red phosphorescence with quantitative quantum efficiency in both aerated and degassed CH(2)Cl(2), implying O(2)-independent phosphorescence due to efficient protection of the emitting chromophore center by the organic ligands. Complex 3 exhibits reasonable two-photon absorption (TPA) property with a cross section of σ ≈ 45 GM (800 nm), which is comparable to the value of commercially available TPA dyes such as coumarin 151. Computational studies have been performed to correlate the structural and photophysical features of the complexes studied. The metal-centered triplet emission within the heterometallic core is suggested to play a key role in the observed phosphorescence. The luminescence spectrum of 1 in CH(2)Cl(2) shows dual phosphorescence maximized at 575 nm (the P(1) band) and 770 nm (the P(2) band). Both P(1) and P(2) bands possess identical excitation spectra, i.e., the same ground-state origin, and the same relaxation dynamics throughout the temperature range of 298-200 K. The dual emission of 1 arises from fast structural fluctuation upon excitation, perhaps forming two geometry isomers, which exhibit distinctly different P(1) and P(2) bands. The scrambling dynamics might require large-amplitude motion and, hence, is hampered in rigid media, as evidenced by the single emission for 1a (610 nm) and 1b (570 nm) observed in solid.
二膦基金阳离子配合物Au(2)(PPh(2)-C(2)-(C(6)H(4))(n)-C(2)-PPh(2))(2)（n=0,1,2,3）与聚合炔烃（AuC(2)Ph)(n)和（AgC(2)Ph)(n）之间的反应导致了具有通式Au(8+2n)Ag(6+2n)(C(2)Ph)(8+4n)(PPh(2)C(2)(C(6)H(4))(n)C(2)PPh(2))(2)的新型杂金属簇的形成，n=0（1）、1（2）、2（3）、3（4）。通过 NMR 和 ESI-MS 光谱对化合物 1-4 进行了详细表征。化合物 1（n=0）以两种形式（橙色（1a）和黄色（1b））结晶，其中一种（1a）已通过 X 射线晶体学进行了分析。研究了 1-4 的发光行为。化合物 2 和 3 在有氧和无氧 CH(2)Cl(2)中均表现出橙红色磷光，具有定量量子效率，这表明由于有机配体对发射发色团中心的有效保护，磷光不受 O(2)的影响。化合物 3 具有合理的双光子吸收（TPA）特性，截面 σ≈45 GM（800nm），与商业 TPA 染料如香豆素 151 的值相当。进行了计算研究以关联所研究的配合物的结构和光物理特征。建议杂金属核内的金属中心三重态发射在观察到的磷光中起关键作用。在 CH(2)Cl(2)中，1 的发光光谱显示最大 575nm（P(1)带）和 770nm（P(2)带）的双磷光。P(1)和 P(2)带均具有相同的激发光谱，即在 298-200K 的整个温度范围内具有相同的基态起源和相同的弛豫动力学。1 的双发射源于激发时的快速结构波动，可能形成两个几何异构体，它们表现出明显不同的 P(1)和 P(2)带。由于需要大振幅运动，因此在刚性介质中受到阻碍，这可以从 1a（610nm）和 1b（570nm）在固态中观察到的单一发射中得到证明。
