Synthesis and X-ray Crystal Structure Determination of New Zwitterionic Complexes of Titanocene

• Published in: Organometallics Vol. 20; no. 19; pp. 4072 - 4079
• Main Authors: Burlakov, V. V, Arndt, P, Baumann, W, Spannenberg, A, Rosenthal, U, Letov, A. V, Lyssenko, K. A, Korlyukov, A. A, Strunkina, L. I, Minacheva, M. Kh, Shur, V. B
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 17.09.2001; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Physical Sciences; Science & Technology; ALKYNE COMPLEXES; ADDITIONAL LIGANDS; TRIS(PENTAFLUOROPHENYL)BORANE; PERMETHYLTITANOCENE; BIS(TRIMETHYLSILYL)ACETYLENE COMPLEX; REACTIVITY; ZR; METALLOCENE; TITANIUM
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om0103052

The reaction of (η 5-iPrC5H4)2Ti(Me3SiC2SiMe3) (2) with B(C6F5)3 in toluene at room temperature produces the zwitterionic titanium(III) complex (η 5-iPrC5H4)[η 5-{1,3-iPrC5H3B(C6F5)3}]Ti (3) in which the 3-hydrogen atom of one of the C5 rings is substituted by a B(C6F5)3 group. The complex is analogous in its structure to the previously described titanium(III) zwitterion Cp[η 5-C5H4B(C6F5)3]Ti (1) formed in the interaction of B(C6F5)3 with Cp2Ti(Me3SiC2SiMe3). A characteristic feature of both zwitterionic complexes is the presence of coordinative bonds between the ortho-fluorine atoms of two C6F5 substituents and the positively charged titanium center. Complex 1 is also obtained by the reaction of B(C6F5)3 with Cp2Ti(PhC2SiMe3). The oxidation of 1 and 3 by air oxygen affords the zwitterionic titanoxanes {Cp[η 5-C5H4B(C6F5)3]Ti}2O (4) and {(η 5-iPrC5H4)[(η 5-{1,3-iPrC5H3B(C6F5)3}]Ti}2O (5), respectively, which contain two zwitterionic units in the molecule. In each of these units, only one ortho-fluorine atom of a B(C6F5)3 group is involved in the coordination to the titanium atom. Complex 1 readily reacts also with acetone to give the zwitterionic adduct Cp[η 5-C5H4B(C6F5)3]Ti(Me2CO) (6), wherein the molecule of acetone is bonded to the Ti(III) center through the oxygen atom. In this adduct too, only one ortho-fluorine atom of a B(C6F5)3 group is coordinated to the metal.