Hafnium complexes amides

Table 15 Complexes of Ziiconium(IV) and Hafnium(IV) Halides with Sulfoxides, Selenoxides, Amides, Af-Oxides, P-Oxides and Related Ligands...

Hafnium(IV) bis(perfluorooctanesulfonyl)amide complex Hf[N(S02C8F17)2]4 is a highly reactive and recyclable Lewis add catalyst in Friedel-Crafts acylation and Prins reactions in fluorous biphasic systems at low catalyst loadings (<1 mol%) (Equation 4.23). In these reactions, Hf[N(S02C8F17)2]4 is selectively soluble in the fluorous phase and can be recovered after reaction by simple phase separation. In addition, the catalyst can be reused without any loss of activity [44],... 

This reaction has been extended to the reaction between aldehydes and alkenyl complexes of boranes, silanes, and stannes to give allylic alcohols, " where the reaction with alkenyl complexes of silanes is known as the silyl-Prins reaction. In addition, several Lewis acids-mediated or -promoted Prins reactions have recently been developed, including the application of TMSI, hafnium (IV) bis(perfluorooctanesulfonyl)amides (in fluorous biphase system),iron (III) species," and 2,6-di-f rf-butylphenoxy(difluoro)borane. J... 

MUanov, A., Bhakta, R., Bannemann, A., Becker, H., Thomas, R., Ehrhart, R, Winter, M., Devi, A. (2006) Guanidinate-stabilized monomeric hafnium amide complexes as promising precursors for MOCVD of Hf02. Inorganic Chemistry, 45,11008-11018. 

Group 4 (IV B) dithiocarbamate chemistry is constrained to the 4-4 oxidation state. The first reported example was the eight-coordinate tetrakis(dithiocarba-mate) titanium complex, [Ti(S2CNBz2)4], prepared by Dermer and Femelius in 1934 (608), while the heavier zirconium and hafnium analogues were first prepared by Bradley and Gitlitz (193) from the reaction of metal amides, [M(NR2)4] (M = Ti, Zr, Hf), with carbon disulfide. 

---