Fortin Daniel, Clément Sébastien, Gagnon Karl, Bérubé Jean-François, Stewart Michael P, Geiger William E, Harvey Pierre D
Département de Chimie, Université de Sherbrooke, 2550 Boul. Université, Sherbrooke, PQ, Canada J1K 2R1.
Inorg Chem. 2009 Jan 19;48(2):446-54. doi: 10.1021/ic800857v.
The new conjugated organometallic polymer (-spacer-C[triple bond]C-Pt(PBu3)2-C[triple bond]C-)n (3; spacer = para-bis(diphenyl(tetramethyl)quinone diimine) and the cyclic mononuclear model complex, spacer'-C[triple bond]C-Pt(PEt3)2-C[triple bond]C x CuCl (4; spacer' = ortho-diphenyl-2,3,5,6-tetramethyl-1,4-benzoquinone diimine) were synthesized from the 1:1 condensation of the corresponding diethynyl ligands (2-para and 2-ortho (para- and ortho-diethynyl-diphenyl-2,3,5,6-tetramethylquinone diimine), respectively), with the trans-Pt(PBu3)2Cl2 for polymer 3 and cis-Pt(PEt3)2Cl2 for 4. The materials were characterized by GPC, DSC, ATG, and electrochemistry for polymer 3, and by X-ray diffraction for 4. Polymer 3 exhibits a M(n) of 18500, M(w) of 25000 with a PD of 1.37. The trans-geometry about Pt in polymer 3 was confirmed by 31P NMR and IR/Raman spectroscopy. The cyclic voltammogram study on the model complex trans-Pt(PBu3)2(C[triple bond]CPh)2, spacer 1-para (Me3Si-C[triple bond]C-R-C[triple bond]C-SiMe3; R = para-diphenyl-2,3,5,6-tetramethyl-1,4-benzoquinone diimine) and polymer 3 demonstrated that polymer 3 in the presence of trifluoroacetic acid (TFA) exhibits a quasi reversible 2-electron reduction process centered at 0.48 V versus SCE corresponding to the reduction of the protonated quinone diimine unit into the corresponding diamine. The UV-vis spectra of the spacer 2-para (440 nm) and polymer 3 (502 nm) are characterized by red-shifted charge transfer (CT) absorptions (C6H4C[triple bond]C --> quinone diimine for 2-para; and (C6H4C[triple bond]C)2Pt --> quinone diimine for polymer 3). These assignments are corroborated by density-functional theory (DFT) and time-dependent density-functional theory (TDDFT) computations. Polymer 3 is not luminescent in the solid state or in solution at 77 K and 298 K.
新型共轭有机金属聚合物(-间隔基-C≡C-Pt(PBu₃)₂-C≡C-)ₙ(3；间隔基 = 对二(二苯基(四甲基)醌二亚胺))和环状单核模型配合物，间隔基'-C≡C-Pt(PEt₃)₂-C≡C·CuCl(4；间隔基' = 邻二苯基-2,3,5,6-四甲基-1,4-苯醌二亚胺)由相应的二乙炔基配体(分别为2-对和2-邻(对-和邻-二乙炔基-二苯基-2,3,5,6-四甲基醌二亚胺))与反式-Pt(PBu₃)₂Cl₂(用于聚合物3)和顺式-Pt(PEt₃)₂Cl₂(用于4)按1:1缩合反应合成。通过凝胶渗透色谱法(GPC)、差示扫描量热法(DSC)、热重分析(ATG)和电化学方法对聚合物3进行表征，通过X射线衍射对4进行表征。聚合物3的数均分子量M(n)为18500，重均分子量M(w)为25000，分散度PD为1.37。聚合物3中Pt的反式构型通过³¹P核磁共振和红外/拉曼光谱得以证实。对模型配合物反式-Pt(PBu₃)₂(C≡CPh)₂、间隔基1-对(Me₃Si-C≡C-R-C≡C-SiMe₃；R = 对二苯基-2,3,5,6-四甲基-1,4-苯醌二亚胺)和聚合物3的循环伏安图研究表明，在三氟乙酸(TFA)存在下，聚合物3表现出以相对于饱和甘汞电极(SCE)为0.48 V为中心的准可逆2电子还原过程，这对应于质子化醌二亚胺单元还原为相应的二胺。间隔基2-对(440 nm)和聚合物3(502 nm)的紫外-可见光谱的特征在于电荷转移(CT)吸收峰发生红移(对于2-对为C₆H₄C≡C→醌二亚胺；对于聚合物3为(C₆H₄C≡C)₂Pt→醌二亚胺)。这些归属通过密度泛函理论(DFT)和含时密度泛函理论(TDDFT)计算得到证实。聚合物3在77 K和298 K的固态或溶液状态下均不发光。
