Titanium imido complexes of pendant arm functionalised benzamidinate ligands

Bis(μ-N-n-propyl-N-trimethylsilylbenzamidinato)bis[(diethyl ether-O)lithium]

“…The title compound was prepared according to previously described procedures (Boyd et al, 2002). Crystallization of the crude product from a mixture of hexane and Et 2 O afforded the title compound as air-sensitive colourless blocks.…”

“…New types of amidinate ligands with pendant amine or pyridine functionalities have recently been reported (Brandsma et al, 1998;Doyle et al, 2000;Kincaid et al, 1999). We have been interested in developing the chemistry of pendant-arm-functionalized amidinates as supporting ligands for group 4 imido chemistry (Boyd et al, 2002). As part of these studies, we were interested in using an N-propyl-substituted benzamidinate ligand, namely Me 3 SiNC(Ph)NCH 2 CH 2 CH 3 , for comparison with the pendant alkylamine-substituted amidinates Me 3 SiNC(Ph)-NCH 2 CH 2 NMe 2 and Me 3 SiNC(Ph)NCH 2 CH 2 CH 2 NMe 2 (Brandsma et al, 1998;Doyle et al, 2000).…”

Amidinate group 4 complexes in the polymerization of olefins

“…Since the immobilization of the ligand by the introduction of EDG was unsuccessful, because the methoxy groups were not coordinated to the metal center, an alkyl moiety was introduced which was connected to an electron donating pendant arm. 88,89 The denticity of the ligands has been shown to vary as a function of the central metal atom size, thus increasing the coordination number as the size of the metal center increases. 90,91 A number of bisIJbenzamidinate)titanium bis(dimethylamido) complexes have been prepared containing variable pendant arms (40)(41)(42)(43) by reacting two equivalents of the neutral amidines with one equivalent of Ti(NMe 2 ) 4 .…”

“…88,89 The denticity of the ligands has been shown to vary as a function of the central metal atom size, thus increasing the coordination number as the size of the metal center increases. 88,89 The denticity of the ligands has been shown to vary as a function of the central metal atom size, thus increasing the coordination number as the size of the metal center increases.…”

Bis(2-butyl-N,N′-diisopropylamidinato)dichlorohafnium(IV)

“…By varying the organic substituents on the N atom as well as on the bridging C atom, it is possible to adjust the coordination of the ligand on the metal center, as has been shown in the case of germanium and silicon (Karsch et al, 1998). However, the amidinate chemistry of group 4 elements has mostly been investigated for titanium and zirconium (Littke et al, 1998;Wood et al, 1999;Boyd et al, 2002;Li et al, 2003). A search of the May 2005 release of the Cambridge Structural Database (Allen, 2002) for structures containing the [ n RC(NR) 2 ] 2 Hf fragment revealed no similar complex containing two amidinate ligands attached to a hafnium center.…”