A series of novel 6,6'‐diphenyl‐2,2'‐bipyridine ligands modified with the substituents at phenyl and bipyridine moieties have been prepared and used in the synthesis of pincer platinum chloride complexes 1–3, [Pt(NNC–R)Cl], where NNC–R – dimethyl 6,6'‐diphenyl‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = H, (1)), dimethyl 6,6'‐bis(4‐fluorophenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = F (2)), dimethyl 6,6'‐bis(4‐methoxyphenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = OMe (3)). Reactions of the obtained compounds with triphenylphosphine proceed through unusual pathway, which gives the [Pt(NNC–R)(PPh₃)₂Cl] products (1a–3a) containing two phosphine ligands, with the chloride retained in coordination sphere and diphenyl‐bipyridine fragment coordinated in η¹‐mode through metalation of a pyridine ring. All complexes have been characterized with mass‐spectrometry and NMR spectroscopy, solid‐state structure of 1–3 and 1a, 3a was revealed by using XRD crystallography. The complexes 1–3 are phosphorescent in dichloromethane solution and in solid state. Their photophysical characteristics were determined and analyzed by DFT calculations, which gave assignment of emissive excited state character with the major contribution from the intraligand charge transfer (³ILCT, Ph→bipyridine) and ligand centered (³LC, bipyridine fragment) transitions.

中文翻译：

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含6,6'-二苯基-2,2'-联吡啶配体的Platinum（II）钳配合物的异常反应性和光物理性质

已制备了一系列在苯基和联吡啶部分进行了取代基修饰的新颖的6,6'-联苯-2-2,2'-联吡啶配体，并用于合成钳型氯化铂络合物1-3，[Pt（NNC–R ）Cl]，其中NNC–R –二甲基6,6'-二苯基-[2,2'-联吡啶] -5,5'-二羧酸盐（R = H，（1）），二甲基6,6'-bis（ 4-氟苯基）-[2,2'-联吡啶] -5,5'-二羧酸酯（R = F（2）），二甲基6,6'-双（4-甲氧基苯基）-[2,2'-联吡啶] -5,5'-二羧酸盐（R = OMe（3））。所得化合物与三苯膦的反应通过异常途径进行，得到了[Pt（NNC–R）（PPh ₃）₂ Cl]产物（1a–3a）含有两个膦配体，用氯化物保留在协调在η配位球和二苯基联吡啶片段^1个通过吡啶环的金属化-mode。所有配合物均已通过质谱和NMR光谱进行了表征，使用XRD晶体学显示了1-3和1a，3a的固态结构。配合物1-3在二氯甲烷溶液中呈固态发磷光。通过DFT计算确定并分析了它们的光物理特性，给出了发射激发态特征，主要由配体内电荷转移（³ ILCT，Ph→联吡啶）和配体中心（³ LC，联吡啶片段）转变。