Second-sphere co-ordination of cationic rhodium complexes [Rh(L)(NH<sub>3</sub>)<sub>2</sub>]<sup>+</sup>by dibenzo-3n-crown-n ethers [n= 6–12; L = cyclo-octa-1,5-diene (cod) or norbornadiene (nbd)]. Solution<sup>1</sup>H nuclear magnetic resonance spectroscopic studies and X-ray crystal structures of [Rh(cod)(NH<sub>3</sub>)<sub>2</sub>·db-21-c-7][PF<sub>6</sub>], [Rh(cod)(NH<sub>3</sub>)<sub>2</sub>·db-24-c-8][PF<sub>6</sub>], [Rh(cod)(NH<sub>3</sub>)<sub>2</sub>·db-30-c-10][PF<sub>6</sub>], [Rh(nbd)(NH<sub>3</sub>)<sub>2</sub>·db-24-c-8][PF<sub>6</sub>], and [{Rh(cod)(NH<sub>3</sub>)<sub>2</sub>}<sub>2</sub>·db-36-c-12][PF<sub>6</sub>]<sub>2</sub>
作者:Howard M. Colquhoun、Simon M. Doughty、J. Fraser Stoddart、Alexandra M. Z. Slawin、David J. Williams
DOI:10.1039/dt9860001639
日期:——
X-ray studies of the isolated 1 : 1 adducts. [Rh(cod)(NH3)2·db-21-c-7][PF6] is monoclinic, space group P21/c, a= 9.121(1), b= 23.405(2), c= 16.705(3)Å, β= 96.30(1)°, Z= 4, R= 0.047. [Rh(cod)(NH3)2·db-24-c-8][PF6] is monoclinic, P21/c, a= 9.1 95(3), b= 29.380(9), c= 13.900(6)Å, β= 93.04(3)°, Z= 4, R= 0.043. [Rh(cod)(NH3)2·db-30-c-10][PF6] is monoclinic, P21/c, a= 9.268(2), b= 34.335(7), c= 13.421(3)Å,
形式为[Rh(L)(NH 3)2 ] [PF 6 ] [L =环辛-1,5-二烯(cod)或降冰片二烯(nbd)]的阳离子铑(I)络合物溶解在卤化碳溶剂中通过添加等摩尔量的冠醚,例如18-crown-6(18-c-6)或二苯并3- n - crown- n(n = 6–12)醚(db-3 n -c- n) 。增溶是形成稳定的,高度结构化的第二球配位络合物的结果,其中大环聚醚通过多个氢键形成与铑上的胺配体相互作用。1个CD 2 Cl 2中的H Nmr光谱研究表明,当某些db-3 n -c- n醚(n = 7–10)优先于18-c-6使用,这表明二烯正在受到冠醚苯并环的各向异性环电流屏蔽。该屏蔽所需的配位二烯和db-3 n -c- n醚芳族环的紧密接近性已通过对分离的1:1加合物进行单晶X射线研究证实。[Rh(cod)(NH 3)2·db-21-c-7] [PF 6 ]是单斜的,空间群P 2 1