| This investigation has demonstrated that phenylalkynylboranes, such as phenylbis(phenylethynyl)borane, tris(phenylethynyl)borane and phenylbis(3-phenyl-2-propynyl)borane, can be synthesized via lithium-boron exchange reactions. 1-Methyl 2,3,4,5-tetraphenylaluminole and a 1:2 complex of 9,10-dimethyl-9,10-dialumina-anthracene with Me 3SnCl were synthesized via tin-aluminum exchange reactions. A 1:1 mixture of 1-methyl-2,3,4,5-tetraphenylaluminole or MeAlCl2 in toluene with Cp2TiCl2 polymerizes ethylene.; The divalent Group 4 metal complexes of the type, MtCl 2(THF)2 and MtCl2-2LiCl (Mt = Ti, Zr, Hf) were prepared by the interaction of MtCl4 with two equivalents of BuLi in THF or in toluene, respectively, and a combination of these complexes with methylaluminoxane (MAO) polymerizes ethylene. The Group 4 methylene complexes, H2C=Mt(THF)2 (Mt = Zr, Ho mixed with LiCl, were synthesized by the interaction of MtCl4 with four equivalents of MeLi in THF. The interaction of these methylene complexes with N-benzylideneaniline, benzophenone and acetophenone, give products showing that they are potent imine and carbonyl-methylenating reagents.; This study has also demonstrated that the complexes, ClMtCH 2AlCl2 (Mt = Ti, Zr, Hf), can be synthesized by the interaction of MtCl4 with two equivalents of Me 3Al in toluene. These complexes polymerize alpha-olefins and cyclotrimerize or polymerize acetylenes via a novel process referred to as epimetallation, whereby through oxidative addition a metallacyclopropane-or-propene intermediate is formed as the active catalyst site. For instance, ClM tCH2AlCl2 polymerizes ethylene, propylene (into a 1:1 mixture of atactic and isotactic polypropylene) and 1-hexene (into predominantly isotactic poly(1-hexene)). Such complexes, ClMtCH2AlCl 2, also individually cyclotrimerizes 1-hexene into 1,2,4-and-1,3,5-tributylbenzenes, cyclotrimerize diphenylacetylene into hexaphenylbenzene and cyclotrimerize (Ti, Zr) or polymerize phenylacetylene (Hf) into 1,2,4- and 1,3,5-triphenylbenzenes and poly(phenylacetylene), respectively. Moreover, the complex ClMtCH 2AlCl2 (Mt = Ti, Zr), mixed with Me2AlCl, dimerizes 1,1-diphenyl-ethylene with accompanying carbocyclization to give 1,1,3-triphenyl-3-methylindan in good yield.; Furthermore, the complexes, ClMtCH2AlCl2 (Mt = Ti, Zr, Hf), cause the catalytic rearrangement of trans stilbene oxide, into 2,2-diphenylacetaldehyde in excellent yields (91–96%) while yielding a small amount of trans-stilbene (4–9%). Finally, the complexes, ClMtCH2AlCl 2 (Mt = Ti, Zr, Hf), interact with benzophenone to give, 1,1-diphenylethylene and 1,1,2,2-tetraphenylethylene. The mode of synthesis of ClTiCH2AlCl2 has been extended to other complexes of titanium and the reactivity of these complexes with ethylene and acetylenes has been investigated. |
