Arce Pablo, Vera Cristian, Escudero Dayra, Guerrero Juan, Lappin Alexander, Oliver Allen, Jara Danilo H, Ferraudi Guillermo, Lemus Luis
Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estación Central, Santiago, Chile.
Dalton Trans. 2017 Oct 10;46(39):13432-13445. doi: 10.1039/c7dt02244a.
A set of new copper(i) complexes is synthesized and characterized using a labile PNP pincer ligand (PNP = N,N'-bis(diphenylphosphine)-2,6-diaminopyridine). A homoleptic Cu(i) complex [Cu(PNP-κP:κN)], (1), was prepared, and taking advantage of the uncoordinated phosphorus atoms in (1), reaction with a second Cu(i) atom bearing secondary ligands (PPh, phen or dmp) allows the formation of new complexes: a bimetallic helicate [Cu(PNP)(phen)], (2), a mononuclear pincer complex [Cu(PNP)(PPh)], (3), and a heteroleptic complex [Cu(PNP)(dmp)], (4). All complexes were characterized by X-ray crystallography, NMR (VT-NMR for (1) and (4)), cyclic-voltammetry, and steady-state and time-resolved luminescence spectroscopy. The fluxional behavior in (1) was studied by P VT-NMR, where an E value of 47.42 kJ mol was calculated for the intramolecular alternating coordination of -PPh moieties in PNP to the metal atom. This set of compounds reveals the versatility of the PNP ligand when added to the coordinating properties of Cu(i). The four complexes exhibit emission in solution and complexes (2)-(4) display intense luminescence in the solid state. The oscillographic traces showing the decay of the luminescence were fitted to biexponential functions with time constants: 8.0 μs > τ > 0.37 μs and 50 μs >τ > 2.2 μs for complexes (2), (3) and (4), respectively. Radiative relaxation is associated with electronic transitions in both the ligand PNP and metal-to-ligand charge transfer (MLCT).
使用一种不稳定的 PNP 钳形配体（PNP = N,N'-双（二苯基膦）-2,6-二氨基吡啶）合成并表征了一组新的铜（I）配合物。制备了一种同配型铜（I）配合物[Cu(PNP-κP:κN)]，(1)，利用(1)中未配位的磷原子，与带有二级配体（PPh、phen 或 dmp）的第二个铜（I）原子反应，可形成新的配合物：双金属螺旋配合物[Cu(PNP)(phen)]，(2)，单核钳形配合物[Cu(PNP)(PPh)]，(3)，以及杂配型配合物[Cu(PNP)(dmp)]，(4)。所有配合物均通过 X 射线晶体学、核磁共振（(1)和(4)采用变温核磁共振）、循环伏安法以及稳态和时间分辨发光光谱进行了表征。通过磷变温核磁共振研究了(1)中的动态行为，计算出 PNP 中-PPh 基团与金属原子分子内交替配位的 E 值为 47.42 kJ/mol。这组化合物揭示了 PNP 配体在赋予铜（I）配位性质时的多功能性。这四种配合物在溶液中均有发射，配合物(2)-(4)在固态时表现出强烈的发光。显示发光衰减的示波器轨迹分别用时间常数为 8.0 μs > τ > 0.37 μs 和 50 μs >τ > 2.2 μs 的双指数函数拟合，分别对应配合物(2)、(3)和(4)。辐射弛豫与配体 PNP 中的电子跃迁以及金属到配体的电荷转移（MLCT）有关。
