Larger and more weakly coordinating anions: Nb(OTeF[sub 5])[sub 6][sup [minus]] and Ti(OTeF[sub 5])[sub 6][sup 2[minus]]

• Published in: Journal of the American Chemical Society Vol. 114:27
• Main Authors: Van Seggen, D.M., Hurlburt, P.K., Anderson, O.P., Strauss, S.H.
• Format: Journal Article
• Language: English
• Published: United States 30.12.1992
• Subjects: 400201 - Chemical & Physicochemical Properties; ANIONS; CHALCOGENIDES; CHARGED PARTICLES; CHEMICAL PREPARATION; CHEMICAL PROPERTIES; COMPLEXES; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONS; NIOBIUM COMPLEXES; OXIDES; OXYGEN COMPOUNDS; SALTS; SOLVENTS; SYNTHESIS; TELLURIUM COMPOUNDS; TELLURIUM FLUORIDES; TELLURIUM HALIDES; TELLURIUM OXIDES; TITANIUM COMPLEXES; TRANSITION ELEMENT COMPLEXES
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00053a066

The ability to generate coordinative unsaturation for a wide variety of cationic species (e.g., [SiR[sub 3]][sup +], [Fe(Por)][sup +], [Re(Cp)(NO)(PPh[sub 3])][sup +], [ZrCp[prime][sub 2]R][sup +]) in solution remains an elusive goal for synthetic and catalytic chemists because no solvent or anion is truly noncoordinating. Recent examples of larger and more weakly coordinating anions include fluorinated derivatives of BPh[sub 4][sup [minus]] such as B(C[sub 6]F[sub 5])[sub 4][sup [minus]] and B(3,5-C[sub 6]H[sub 3](CF[sub 3])[sub 2])[sub 4][sup [minus]6], CB[sub 11]H[sub 12][sup [minus]] and related carborane anions, and heteropolyanions (Keggin ions) such as PW[sub 12]O[sub 40][sup 3[minus]]. The authors are investigating a class of even larger complex anions, M(OTeF[sub 5])[sub 6][sup n[minus]], and have found that they are (i) much less coordinating, (ii) much more stable in the presence of electrophiles, and (iii) much more solubilizing in weakly coordinating solvents than either B(OTeF[sub 5])[sub 4][sup [minus]] or Pd(OTeF[sub 5])[sub 4][sup 2[minus]]. The anions that are the subject of this paper are Nb(OTeF[sub 5])[sub 6][sup [minus]] and Ti(OTeF[sub 5])[sub 6][sup 2[minus]], which had been prepared previously as their TBA[sup +] or Cs[sup +] salts, respectively. The authors have prepared their Ag[sup +] salts, which should prove useful as metathesis reagents, by mixing either NbCl[sub 5] or TiCl[sub 4] with 6 equiv of AgOTeF[sub 5] in 1,1,2-trichlorotrifluoroethane (CFC-113). 22 refs., 1 fig.