200951-85-5Relevant academic research and scientific papers
Neutral and cationic group 4 complexes containing bis(borylamide) ligands, [R2BNCH2CH2NBR2]2-(R = 2,4,6-i-Pr3C2H2, M = Zr; R = cyclohexyl, M = Ti, Zr, Hf)
Warren, Timothy H.,Schrock, Richard R.,Davis, William M.
, p. 308 - 321 (2008/10/08)
Reaction of Li2(TripBen)(THF)4 ([(2,4,6-i-Pr3C6H2)2BNCH2CH 2NB(2,4,6-i-Pr3C6H2) 2]2~ = (TripBen)2-) with ZrCl4(THF)2 in toluene cleanly provides (TripBen)ZrCl2. (TripBen)ZrCl2 can be alkylated with Grignard reagents to yield the dimethyl (2), diethyl (3), and dibutyl (4) derivatives, (TripBen)ZrR2. The structure of (TripBen)Zr(CD3)2 reveals that π bonding between boron and nitrogen results in one Trip ring on each boron being oriented over the two alkyl groups. The reaction between (TripBen)ZrMe2 and B(C6F5)3 in pentane yields colorless crystals of {(TripBen)ZrMe}{MeB(C6F5)3} (5a). The dialkyl complexes 2-4 react with [HNMe2Ph][B(C6F5)4] in toluene to yield free dimethylaniline and species that are identical to 5a according to NMR spectra. (CyBen)M(CH2SiMe3)2 complexes ([(cyclohexyl)2- BNCH2CH2NB(cyclohexyl)2]2- = (CyBen)2-) are prepared by the reaction between Li2(CyBen)- (ether) and M(CH2SiMe3)2Cl2(ether)x (M = Ti, Zr, or Hf). (CyBen)MI2 complexes are formed upon treating (CyBen)M(CH2SiMe3)2 complexes with iodine. A variety of (CyBen )MR2 species can be prepared, including those in which the alkyl contains β protons. The molecular structure of (CyBen)Zr(CH2CH3)2 shows it to be a relatively symmetric species in which one cyclohexyl ring on each boron is located directly over the two ethyl ligands. Diisobutyl complexes (CyBen)M(CH2CHMe2)2 react with [Ph3C][B(C6F5)4] in chlorobenzene at -30°C to give the cations [(CyBen)M(CH2CHMe2)][B(C6F5) 4], which are believed to be stabilized by coordination of chlorobenzene or toluene. Chlorobenzene solutions of [(CyBen)M(CH2CHMe2)- (S)][B(C6F5)4] (M = Zr, Hf; S = chlorobenzene) polymerize 225 equiv of 1-hexene quantitatively at -30°C to give regioregular poly(1-hexene) of high molecular weight (Mn = (0.4- 1.3) × 105 g/mol) and high polydispersity (5-6).
