This paper reports the reactions of a monomeric aluminum dihydride LAlH2(L = HC[C(Me)N(Ar)]2,Ar = 2,6-i-Pr2C6H3) with diazo,azido,and terminal alkyne compounds.The reaction of LAlH2 with N2CH(SiMe3) and N3(1-Ad) occurred through an Al-H addition to end-on nitrogen to yield respective compounds LAl[N(H)N = CH(SiMe3)]2(1) and LAl[N(H)N=N(1-Ad)]2(2),while the reaction of LAlH2 with PhC≡CH occurred through a stepwise deprotonation to yield LAlH(C≡CPh)(5) and LAl-(C≡CPh)2(6),respectively.2 further reacted by N2-release to yield LAl[NH(1-Ad)][N(H)N=N(1-Ad)](3) and LAl[NH-(1-Ad)]2(4) upon the increased temperature treatment.Compounds 1-6 have been fully characterized,revealing novel reactivity patterns of LAlH2 toward different substrates under the steric influence from the bulky L ligand at Al.
CHU ChenHui1,YANG Ying1,2 & ZHU HongPing1 1State Key Laboratory of Physical Chemistry of Solid Surfaces
The preparation of divalent chromium N-heterocyclic carbene（NHC,1,3-diisopropyl4,5-dimethylimidazole-2-ylidene） compounds is reported.The reaction of 1：1 molar ratio of NHC with CrCl2 led to an isolation of [（NHC）CrCl（μ-Cl）（THF）]2（1）,while that of 2：1 ratio resulted in the formation of（NHC）2CrCl2（2）.1 can be considered as an intermediate in the formation of 2 and further converted into 2 by the addition of another equiv.of NHC.The reaction of 2 with CpNa afforded an ion pair compound [（NHC）2CrCp]＋[Cp]-（3）,indicating a strong coordination ability of NHC supplanting one of the ionic Cr-Cp bonding.In combination of methylalumoxane（MAO） as cocatalyst 1 and 2 both are active for catalyzing ethylene polymerization.
