Tanabe Makoto, Osakada Kohtaro
Chemical Research Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Chemistry. 2004 Jan 23;10(2):416-24. doi: 10.1002/chem.200305344.
The reaction of dimethyl acetylenedicarboxylate (DMAD) with [Pt(SiHPh(2))(2)(PMe(3))(2)] produces cis-[Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(PMe(3))(2)] (cis-1, Z = COOMe) and [Pt(CZ=CZ-SiPh(2))(PMe(3))(2)] (2) depending on the reaction conditions. cis-1 and 2 are equilibrated in solution at room temperature, and they are isolated by recrystallization of the mixtures. cis-1 is converted slowly in solution into trans-[Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(PMe(3))(2)] (trans-1) via intermediate 2 followed by reaction with H(2)SiPh(2). DMAD also reacts with [Pt(SiHPh(2))(2)(dmpe)] (dmpe = 1,2-bis(dimethylphosphino)ethane) to afford [Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(dmpe)] (3). Conversion of 3 into 4-sila-3-platinacyclobutene [Pt(CZ=CZ-SiPh(2))(dmpe)] (4) takes place, accompanied by formation of H(2)SiPh(2), to give an equilibrated mixture of the two complexes. Crystallographic and spectroscopic data of cis-1, trans-1, and 3 suggest the presence of an intramolecular interaction between the Si-H group of the 3-sila-1-propenyl ligand and Pt via an Si-H-Pt three-center-four-electron bond in the solid state and in solution. DMAD reacts with 2 to give 5-sila-2-platina-1,4-cyclohexadiene with pi-coordinated DMAD, [Pt(CZ=CZ-SiPh(2)-CZ=CZ)(DMAD)(PMe(3))(2)] (5), which is also obtained from the reaction of excess DMAD with [Pt(SiHPh(2))(2)(PMe(3))(2)]. Unsymmetrical six-membered silaplatinacycles without pi-coordinated alkyne, [Pt(CZ=CZ-SiPh(2)-CH=CX)(PMe(3))(2)] (6: X = COOMe; 7: X = Ph), are prepared analogously from the respective reactions of phenyl acetylene and of methyl acetylene carboxylate with 2. Methyl 2-butynolate reacts with 2 at 50 degrees C to form a mixture of the regioisomers [Pt(CZ=CZ-SiPh(2)-CMe=CZ)(PMe(3))(2)] (8) and [Pt(CZ=CZ-SiPh(2)-CZ=CMe)(PMe(3))(2)] (9).
二甲基乙炔二羧酸酯（DMAD）与[Pt(SiHPh(2))(2)(PMe(3))(2)]反应，根据反应条件生成顺式-[Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(PMe(3))(2)]（顺式-1，Z = COOMe）和[Pt(CZ=CZ-SiPh(2))(PMe(3))(2)]（2）。顺式-1和2在室温下于溶液中达到平衡，通过混合物重结晶将它们分离出来。顺式-1在溶液中通过中间体2缓慢转化为反式-[Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(PMe(3))(2)]（反式-1），随后与H(2)SiPh(2)反应。DMAD还与[Pt(SiHPh(2))(2)(dmpe)]（dmpe = 1,2-双（二甲基膦基）乙烷）反应，得到[Pt(CZ=CZ-SiHPh(2))(SiHPh(2))(dmpe)]（3）。3转化为4-硅-3-铂环丁烯[Pt(CZ=CZ-SiPh(2))(dmpe)]（4），同时伴有H(2)SiPh(2)的形成，生成两种配合物的平衡混合物。顺式-1、反式-1和3的晶体学和光谱数据表明，在固态和溶液中，3-硅-1-丙烯基配体的Si-H基团与Pt之间通过Si-H-Pt三中心四电子键存在分子内相互作用。DMAD与2反应生成具有π配位DMAD的5-硅-2-铂-1,4-环己二烯，[Pt(CZ=CZ-SiPh(2)-CZ=CZ)(DMAD)(PMe(3))(2)]（5），它也可由过量的DMAD与[Pt(SiHPh(2))(2)(PMe(3))(2)]反应得到。不含π配位炔烃的不对称六元硅铂环，[Pt(CZ=CZ-SiPh(2)-CH=CX)(PMe(3))(2)]（6：X = COOMe；7：X = Ph），分别由苯乙炔和甲基乙炔羧酸酯与2的相应反应类似地制备。2-丁炔酸甲酯在50℃与2反应，形成区域异构体[Pt(CZ=CZ-SiPh(2)-CMe=CZ)(PMe(3))(2)]（8）和[Pt(CZ=CZ-SiPh(2)-CZ=CMe)(PMe(3))(2)]（9）的混合物。
