The two neutral complexes [Re(CO)3(H−1taci)] ( 1 ) and [ReO3(H−1taci)] ( 2 ) (taci=1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol) were synthesized from the conventional ReI and ReVII precursors (Et4N)2[ReBr3(CO)3] and [ReO3(OSnMe3)]. The crystal structures of 1 and 2 , which were determined by single crystal X‐ray analysis, are virtually isomorphous. Both compounds crystallize in the orthorhombic space group Pnma, Z=4; 1 : a=14.806(3), b=8.466(2), c=9.781(2) Å, 2 : a=13.050(2), b=8.732(1), c=9.061(1) Å. In both complexes, the monodeprotonated H−1taci ligand is bonded to the Re center in an N,O,N‐coordination mode. The resulting molecular Cs symmetry is retained in the crystal structure and confirmed by IR spectroscopy of solid‐state samples. The observed binding mode of the ligand is discussed in terms of steric and electronic effects. 相似文献
Summary: Norbornene (NB) was oligomerized at 0 °C using AlEt2Cl‐TiCl4 at a monomer/titanium molar ratio of about 11. The oligomerization product consists of a fraction soluble in diethyl ether, amorphous by X‐ray examination, and of a crystalline fraction, insoluble in diethyl ether. The crystalline fraction was shown by powder X‐ray diffraction to consist of a NB heptamer. Single‐crystal X‐ray analysis indicated that the heptamer had a stereoregular 2,3‐exo‐disyndiotactic structure. The heptamer adopts a strained, highly irregular, folded conformation in the crystalline state. Structural differences with respect to NB oligomers obtained with zirconocene catalysts are discussed.
A view of the molecular structure of the crystalline NB heptamer. 相似文献