Reaction Control of Dynamic Complexes Relevant to Catalysis

(1)1,2-二芳基-3,4-二膦基环丁烯（DPCB-Y）作为低配位磷化合物，对过渡金属具有极强的x受体作用。研究了几种含DPCB-Y配体的有机钯（II）和铂（II）配合物的结构和催化性能。dpcb - y配位钯配合物提供了迄今为止未知的反应性和选择性的高效催化。代表性的例子包括苯胺和活性亚甲基化合物与烯丙醇的脱水烯丙基化，烯丙酯的去烯丙基化，芳基卤化物的胺化和氰化，以及烯酮的氢酰胺化。对苯胺脱水烯丙基化的催化机理进行了详细的研究。(2)含DPCB-Y配体的二氯钌（II）配合物能有效催化二乙基芳烃与HSiMe2Ph的立体选择性硅氢化反应生成（Z，Z）-双（2-溴乙烯基）芳烃，该芳烃与NBS以立体定向的方式进行溴脱硅化反应，得到几何纯度高的（Z，Z）-双（2-溴乙烯基）芳烃。该产物是合成几何纯的全顺式聚苯乙烯（pav）的良好起始材料，在溶液和固体中都能快速光异构化成反式pav。这一现象已被应用于石英衬底上pav的直接微尺度图案化。(3)含较重硫原子的fischer型钌碳烯RuCl_2(=CHER)(PCy_3)_2 （E = S, Se, Te）催化降冰片烯衍生物与烯基硫族化合物的开环/交叉复合反应，得到高选择性的异二官能化聚降冰片烯。(4)含有大体积膦配体RuCl_2(=C=CHPh)L_2 （L = PPr^i, PCy_3）的乙烯基铕配合物在n -甲基吡咯烷存在下可作为芳基乙炔和硅基乙炔(Z)选择性交叉二聚反应的良好催化剂前驱体。(5)制备了具有不对称杂原子配体的顺式铂配合物- pt (ER_n)(ER_m)(PMe_2Ph)_2 (E, E′= B, Si, Ge, Sn)，并通过动力学实验考察了其对炔插入的反应性。反应性依次为：Pt-B > Pt-Si > Pt-Sn > Pt-Ge。研究了C-B、C-Si和C-Ge在铂（II）中心的还原消除机理。少

(1)1,2-Diaryl-3,4-diphosphinidenecyclobutenes (DPCB-Y) as low-coordinate phosphorus compounds have been found to serve as extremely strong x-acceptors towards transition metals. Structures and catalytic properties of several organo- palladium(II) and-platinum(II) complexes bearing DPCB-Y ligands have been examined. The DPCB-Y-coordinated palladium complexes provide highly efficient catalysis with hitherto unknown reactivity and selectivity. Representative examples include dehydrative allylation of aniline and active methylene compounds with allylic alcohols, deallylation of allylic esters, amination and cyanation of aryl halides, and hydroamidation of enones. Detailed catalytic mechanisms have been examined for dehydrative allylation of aniline.(2)Dichlororuthenium(II) complexes bearing DPCB-Y ligands efficiently catalyze stereoselective hydrosilylation of diethynylarenes with HSiMe2Ph to afford (Z,Z)-bis(2-silylethenyl)arenes, which undergo bromodesilylation with NBS in a stereospecif … More ic manner giving (Z,Z)-bis(2-bromoethenyl)arenes in high geometrical purity (>98%). The products are good staring materials for the synthesis of geometrically pure all-cis poly(arylene vinylene)s (PAVs), which rapidly undergo photoisomerization to trans-PAVs both in solution and in the solid. This phenomenon has been applied to direct microscale patterning of PAVs onto a quartz substrate.(3)The Fischer-type ruthenium carbenes bearing heavier chalcogen atoms RuCl_2(=CHER)(PCy_3)_2 (E = S, Se, Te) catalyze ring-opening/cross-metathesis of norbornene derivatives with alkenyl chalcogenides to give heterodifunctionalized poly(norbornenes) in high selectivities.(4)The vinylideneruthenium complexes bearing bulky phosphine ligands RuCl_2(=C=CHPh)L_2 (L = PPr^i, PCy_3) serve as good catalyst precursors for (Z)-selective cross-dimerization between arylacetylenes and silylacetylenes in the presence of N-methylpyrrolidine.(5)The platinum complexes having unsymmetrical heteroatom ligands cis-Pt(ER_n)(ER_m)(PMe_2Ph)_2 (E, E' = B, Si, Ge, Sn) have been prepared, and their reactivity towards alkyne-insertion has been examined by kinetic experiments. The reactivity decreases in the order : Pt-B > Pt-Si > Pt-Sn > Pt-Ge. The mechanisms of C-B, C-Si, and C-Ge reductive elimination from platinum(II) centers have also been investigated. Less