Generation of Organometallic Conjugated Compounds Applicable for Non-linear Optics

线性共价连接金属簇合物的构建由于其基本成键性质以及作为电子通讯和光电子材料的广阔应用前景而引起了人们极大的兴趣。我们已经报道了一个线性排列的四核配合物Mo_2Pd_2（pyphos）_4（1）的合成和反应。（pyphos=6-二苯基膦基-2-吡啶酮），它是由四重键合的双核钼配合物Mo_2（pyphos）_4（2），与Pd（O）_2（dba）_3（C_6H_6）在THF中反应，最有趣的特征是1的两个Pd（O）原子都与Mo_2核发生配位作用，从而与Pd（O）中心发生配位作用。在室温下与二氯甲烷反应，得到Mo_2PdCl_2（CH_2Cl）_2（pyphos）_4（3）。通过UV光谱监测反应式1的反应，1在二氯甲烷中的深橙子（λ <max>=476 nm）立即变成绿棕色[Pd（I）络合物Mo_2Pd_2Cl ...更多信息 _2（pyphos）_4（4）呈深绿色（λ_<max>=642 nm）]，然后逐渐形成Pd（II）配合物3。发现化合物1与二芳基二硫醚在室温下于THF中发生1，4-加成反应，生成相应的Pd（I）硫醇配合物Mo_2Pd_2（pyphos）_4（SAr）_2（5a-f）。用皮秒简并四波混频（DFWM）方法研究了多键四核配合物M_2Pd_2Cl_2（pyphos）_4（6）和双核配合物M_2（pyphos）_4（7）（a，M=Mo ; B，M=Cr ; pyphos=6-二苯基膦-2-吡啶酮）的非线性光学性质，发现它们具有较大的非线性光学超极化率γ，其中6a（1.5×10 <-30>^esu），6 B（5.2×10^<-31>esu）和7 a（6.9×10^<-31>esu）的γ值大于约10 ^-10 ^esu<-35>的γ值<-33>.过渡金属聚（炔）聚合物的研究，近年来以有机金属配合物为基础的聚合化学的发展是引人注目的。极性烯属单体如丙烯酸甲酯（MA）和甲基丙烯酸甲酯（MMA）的配位聚合已通过使用各种烯醇化物配合物实现。在这方面的贡献，我们要报告的第一个第5族金属配合物的MMA聚合活性。此外，我们提出了一个新的想法，以产生催化活性的烯醇化物配合物的有机金属配合物轴承极性单体作为配体。新合成的钽配合物TaCp^* 的MMA配体（η^2-p-MeOC_6H_4-DAD）（n^4仰卧-MMA）（8）（p-MeOC_6 H_4-DAD= 1，4-双（对甲氧基苯基）-1，4-二氮杂-1，3-丁二烯）和TaCp^*（η^2-Cy-DAD）（η^4-仰卧-MMA）（9）（Cy-DAD= 1，4-二环己基-1，4-二氮杂-1，3-丁二烯）通过添加一当量的AlMe_来活化在-20℃下，以9与1当量AlMe_3的组合为催化剂体系，活性最高;聚合反应在10 min内完成，得到分子量分布窄（Mw/Mn =1.10）的PMMA。少

The construction of linear covalently-linked metal clusters has attracted much interest in view of fundamental bonding as well as promising applications as extensive electronic communications and optoelectronic materials. We have already reported synthesis and reaction of a linearly aligned tetranuclear complex, Mo_2Pd_2(pyphos)_4 (1)(pyphos=6-diphenylphosphino-2-prydonate), which was prepared by treating a quadruply bonded dinuclear dimolybdenum (II) complex, Mo_2(pyphos)_4 (2), with Pd_2(dba)_3(C_6H_6) in THF.The most interesting feature is that both Pd(O) atoms of 1 datively interacted with the Mo_2 core and hence the Pd(O) centers, unlike normal monoculear Pd(O) complexes, reacted oxidatively with dichloromethane at room temperature to give a Pd(II) complex, Mo_2PdCl_2(CH_2Cl)_2(pyphos)_4 (3). On monitoring the reaction of equation 1 by UV spectroscopy, the deep orange color (λ_<max>=476 nm) of 1 in dichloromethane turned immediately to greenish brown [the Pd(I) complex, Mo_2Pd_2Cl … More _2(pyphos)_4 (4) was deep green (λ_<max>=642 nm)], and then gradually resulted in the formation of the Pd(II) complex 3. We found that disulfides oxidatively added to both Pd(O) metals of 1 in a 1,4-addition reaction ; 1 reacted with one equivalent of diaryldisulfides in THF at room temperature to give the corresponding Pd(I)-thiolate complexes, Mo_2Pd_2(pyphos)_4(SAr)_2 (5a-f) in modest yields. Multiply-bonded tetranuclear complexes M_2Pd_2Cl_2(pyphos)_4 (6) and dinuclear complexes M_2(pyphos)_4 (7) (a, M=Mo ; b, M=Cr ; pyphos=6-diphenylphosphino-2-pyridonate) are found to exhibit large hyperpolarizability γ of nonlinear optical property by using the picosecond degenerate four-wave mixingg (DFWM) method ; the γ values of 6a (1.5×10^<-30> esu), 6b (5.2×10^<-31> esu), and 7a (6.9×10^<-31> esu) are greater than those (ca.10^<-35>-10^<-33> esu) of transition metal poly(yne) polymers.Recent development of the polymerization chemistry based on well-defined organometallic complexes is remarkable. Coordination polymerization of polar olefinic monomers such as methyl acrylate (MA) and methyl methacrylate (MMA) has been accomplished by using various enolate complexes. In this contribution, we would like to report the first Group 5 metal complex active for MMA polymerization. Moreover, we present our new idea to generate a catalytically active enolate complex from an organometallic complex bearing a polar monomer as a ligand. The coordinated MMA ligands of newly prepared tantalum complexes TaCp^*(η^2-p-MeOC_6H_4-DAD)(η^4supine-MMA)(8) (p-MeOC_6H_4-DAD=1,4-bis(p-methoxyphenyl)-1,4diaza-1,3-butadiene) and TaCp^*(η^2-Cy-DAD)(η^4-supine-MMA)(9) (Cy-DAD=1,4-dicyclohexyl-1,4-diaza-1,3-butadiene) were activated by addition of one equivalent of AlMe_3 to generate active catalysts for polymerization of MMA.The catalyst system of the highest activity was the combination of 9 and one equiv of AlMe_3 at -20℃ ; the polymerization completed within 10 min to give a PMMA with very narrow polydispersity (M_w/M_n=1.10). Less