Département de Chimie, Université de Sherbrooke, PQ, Canada J1K 2R1.
Inorg Chem. 2010 Mar 15;49(6):2614-23. doi: 10.1021/ic901421m.
Two conjugated organometallic oligomers of the type (-C[triple bond]CPt(L)(2)C[triple bond]C(ZnP)-)(n) and model compounds [PhC[triple bond]CPt(L)(2)C[triple bond]C(ZnP)C[triple bond]CPt(L)(2)C[triple bond]CPh] with L = tri(n-butyl)-phosphine and ZnP = zinc(II)(10,20-bis(Ar)porphyrine) (Ar = mesityl (Mes; P1 and M1) or 3,4,5-trihexadecyloxyphenyl (P2 and M2)) were synthesized and characterized ((1)H and (31)P NMR, HRMS, elemental analysis, IR, GPC, and TGA). GPC indicates that P1 and P2 exhibit respectively approximately 6 and approximately 3 units with a polydispersity of 1.4. M1 was also characterized by X-ray crystallography. The Pt...Pt separation in M1 is 1.61 nm, which makes P1 approximately 9.6 nm long. The spectral measurements show that the absorption and photoluminescence spectra of M1, M2, P1, and P2 are remarkably red-shifted. For example, the low energy Q-band is observed at 677 +/- 1 nm in comparison with their precursors HC[triple bond]C(ZnP)C[triple bond]CH, L1 and L2 (Ar = mesityl (Mes; L1) or 3,4,5-trihexadecyloxyphenyl (L2)), both at 298 and 77 K, for which the Q-band is observed at 622 nm. The photophysical parameters, fluorescence lifetimes (tau(F)), and quantum yields (Phi(F)) show a slight decrease by a factor of approximately 2 (at most 3) following the trend L1 approximately L2 > M1 approximately M2 > P1 approximately P2, a trend explained by a combination of the heavy atom effect and an increase in internal conversion rate due to the increase in oligomer dimension. This small variation of the photophysical data for materials of a few nm in dimension contrasts with the larger change in tau(P), phosphorescence lifetimes of the Pt-containing unit in the (-C(6)H(4)C[triple bond]CPt(L)(2)C[triple bond]C-CC(6)H(4)(ZnP)-)(n) oligomers with n = 3, 6, and 9 reported earlier (Liu, L.; Fortin, D.; Harvey, P. D. Inorg. Chem. 2009, 48, 5891-5900). In this later case, tau(P) decreased by steps of an order of magnitude as n increased from 3 to 6 to 9. This decrease was explained by a T(1) energy transfer from the Pt unit (donor) to MP (acceptor) in combination with an excitonic process (energy delocalization). Because of the full conjugation in P1 and P2, these oligomers behave as distinct molecules, and no energy transfer occurs. These properties make these materials suitable candidates for photocell applications.
两种类型的共轭有机金属寡聚物（-C[三键]CPt（L）（2）C[三键]C（ZnP）-）（n）和模型化合物[PhC[三键]CPt（L）（2）C[三键]C（ZnP）C[三键]CPt（L）（2）C[三键]CPh]，其中 L = 三（正丁基）-膦和 ZnP = 锌（II）（10,20-双（Ar）卟啉）（Ar = 均三甲苯基（Mes；P1 和 M1）或 3,4,5-三己氧基苯基（P2 和 M2））被合成并进行了表征（（1）H 和（31）P NMR、高分辨率质谱、元素分析、IR、GPC 和 TGA）。GPC 表明 P1 和 P2 分别具有约 6 个和约 3 个单元，其多分散性为 1.4。M1 还通过 X 射线晶体学进行了表征。M1 中的 Pt...Pt 分离为 1.61nm，这使得 P1 大约 9.6nm 长。光谱测量表明，M1、M2、P1 和 P2 的吸收和光致发光光谱显著红移。例如，低能量 Q 带在 677 ± 1nm 处观察到，与它们的前体 HC[三键]C（ZnP）C[三键]CH、L1 和 L2（Ar = 均三甲苯基（Mes；L1）或 3,4,5-三己氧基苯基（L2））相比，在 298 和 77K 下，Q 带在 622nm 处观察到。光物理参数、荧光寿命（tau(F)）和量子产率（Phi(F)）显示出轻微的下降，因子约为 2（最多 3），遵循趋势 L1≈L2＞M1≈M2＞P1≈P2，这一趋势可以用重原子效应和由于寡聚物尺寸增加而导致的内转换速率增加的组合来解释。对于几个纳米尺寸的材料，光物理数据的这种微小变化与 tau(P)的较大变化形成对比，tau(P)是先前报道的（-C（6）H（4）C[三键]CPt（L）（2）C[三键]C-CC（6）H（4）（ZnP）-）（n）寡聚物中含 Pt 单元的磷光寿命的变化更大，n = 3、6 和 9（Liu，L.；Fortin，D.；Harvey，P. D. Inorg. Chem. 2009，48，5891-5900）。在这种情况下，tau(P)随着 n 从 3 增加到 6 再增加到 9 而逐渐减少一个数量级。这种下降是由于 Pt 单元（供体）与 MP（受体）之间的 T1 能量转移与激子过程（能量离域）相结合所致。由于 P1 和 P2 中的完全共轭，这些寡聚物表现为不同的分子，并且没有能量转移发生。这些特性使这些材料成为适合光电池应用的候选材料。
