一种新颖的固态钐硒化物Sm_8eS_(10)的结构研究

标题化合物系采用固相法合成得到,化学式为Sm_8Se_(10),四方晶系,I4_1/a空间群,晶胞参数:a=1.2000(7),c=1.4075(30)nm,V=2.027(5)nm^3,F(000)=3344,Z=4,D_c=6.53g/cm^3.结构精修收敛后一致性因子R=0.071,R_w=0.067.化合物中稀土钐的配位多面体系由畸变三方柱演化而来,八个Sm原子构成类S_4N_4的笼状八元环,这些八元环沿晶轴c方向呈现出规整的排列结构.结构数据分析和电阻率测量表明Sm_8Se_(10)具有价态涨落现象,是一个混合价化合物.

A convenient and stereoselective synthesis of (Z)-allyl selenides via Sm/TMSCl system-promoted coupling of Baylis-Hillman adducts with diselenides

A simple and convenient procedure for stercoselective synthesis of （Z）-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCI system to form selemde anions, which then undergo SN2＇ substitution of Baylis-Hillman adducts to produce the （Z）-allyl selenides.