| The synthesis and characterization of Li+ and Ph 3C+ salts of the new weakly coordinating anion ( WCA) Nb(OCH(CF3)2)6- (Nb(HFIP)6-) are reported. Salt-in-polymer electrolytes using amorphous polyethylene oxide (aPEO) were also prepared, (aPEO)nLiNb(HFIP)6 (n = 12, 24, 30). Their glass transition temperatures were found to be 227, 222, and 219 K, respectively. Their 293 K d.c. conductivities were found to be 1.4 x 10-5, 1.0 x 10-4, and 5.0 x 10-5 S cm-1, respectively. Additionally, the lithium salt was found to be an effective catalyst for a Mukaiyama-Michael addition reaction. Its catalytic activity and regioselectivity are similar to those of LiCo(C 2B9H11)2 and are superior to those of LiClO4. Also, the solid state structure of [(C6H 5)3C+][Nb(OCH(CF3)2) 6-] was determined.;Another class of WCAs are the closo-carborane monoanions. The substitution chemistry of one of these anions, CB9H 10- has received relatively little attention. The mono- and dihalogenation of this anion with the electrophilic reagents are presented here. Monohalogenation was found to occur almost exclusively at the lower-belt boron atoms (6-CB9H9X- for X = Cl, Br, I, >95% regioselectively). Dihalogenation formed predominantly 6,8-CB9H8X2-, with varying amounts of 6,7- and 6,10-CB9H8X2- present. The preparation of these monohalogenated anions offers the unique opportunity to compare the spectroscopy of a complete series of anions, 6-CB9H9X- (X= H, F, Cl, Br, I). These anion offer a relatively wide range of reactivity. For example, deuterium exchange is relatively rapid for the unsubstituted and fluorinated derivatives of CB9H10-, but no deuterium exchange was observed even after 1 month for 6-CB9H9I -. Another series of anions, the mixed-halogenated anions, 10-X-6,7,8,9-CB 9H5F4- (X = Br, I) were prepared from 6,7,8,9-CB9H6F4-.;While the monchalogenation of CB9H10- occurred almost exclusively at the 6-position, coordination of the electrophilic cation CpFe(CO)2+ was found to form all three possible linkage isomer (CpFe(CO)2)(10-CB9H 10), (CpFe(CO)2)(6-CB9H10), and (CpFe(CO) 2)(2-CB9H10). Experiments investigating the dependence of linkage isomer formation on solvent and temperature were conducted. In the course of these investigations, it was found that nu(CO) values reported for several putative CpFe(CO)2(WCA) complexes had been misassigned. A possible decomposition scheme involving the formation of CpFe(CO)3+ is proposed. |
