Titanium dialkylamides

The attempted amine exchange reaction to prepare metal amides can be complicated if primary amines are used. Hence, titanium dialkylamides will react with many primary amines to produce polymeric materials (equation 38).66... 

Finally, vanadium alkoxides and dialkylamides, such as [V(OEt)4]2 or V(NR2)4, can be obtained by methods similar to those used for titanium the dialkylamides react with CS2, undergoing a V—N insertion reaction (see page 777) to give eight-coordinate Viv compounds, V(S2CNR,)4.24... 

Titanium tetrakis(dialkylamide) compounds, Ti(NR2)4 (R= Me, Et, n-Pr, n-Bu) have been investigated in the CVD of TiN [144, 154-161]. Their decomposition, carried out in the presence of NH3(g), proceeds under relatively mild conditions and yields TiN films of good quality. Other precursors which have been used for the CVD of TiN include cyclopentadienyl-cycloheptatrienyl titanium, CpTi(C7H7) (15) [161], f-BuTi(NMe)3 [156, 161], [Ti(/i-N-r-Bu)(NMe2)2]2 (16) [156, 161] and Ti(f-BuDAD)2, bis(N,N -di-t-butyl-l,4-diaza-l,3-butadiene) titanium (17) [161]. The mixed amide... 

The benzyl complex of titanium is a very hard starting material (Eq. 2-64), as is the tungsten dialkylamide (Eq. 2-65). 

The convenient preparation of thiolates of titanium " and uranium from their respective dialkylamides, but not from alkoxide analogues, demonstrates the oxophilic nature of these metals in their higher oxidation states. 

However, a very useful adaptation of the original protocol for the conversion of esters to cyclopropanols with titanacydopropane towards a highly versatile preparation of cydopropylamines has been developed [68], N,N-dialkylaminocyclopro-panes with up to three additional substituents are readily obtained from carboxylic acid N,N-dialkylamides and ethyl- as well as substituted ethylmagnesium bromide in the presence of titanium tetraisopropoxide. These transformations were also possible with substoidiiometric amounts of Ti(OPr-i)4, but the yields were significantly better with stoichiometric amounts. 

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