35 research outputs found
Neutral and Cationic Rare Earth Metal Alkyl and Benzyl Compounds with the 1,4,6-Trimethyl-6-pyrrolidin-1-yl-1,4-diazepane Ligand and Their Performance in the Catalytic Hydroamination/Cyclization of Aminoalkenes
A new neutral tridentate 1,4,6-trimethyl-6-pyrrolidin-1-yl-1,4-diazepane (L) was prepared. Reacting L with trialkyls M(CH2SiMe3)3(THF)2 (M = Sc, Y) and tribenzyls M(CH2Ph)3(THF)3 (M = Sc, La) yielded trialkyl complexes (L)M(CH2SiMe3)3 (M = Sc, 1; M = Y, 2) and tribenzyl complexes (L)M(CH2Ph)3 (M = Sc, 3; M = La, 4). Complexes 1 and 2 can be converted to their corresponding ionic compounds [(L)M(CH2SiMe3)2(THF)][B(C6H5)4] (M = Sc, Y) by reaction with [PhNMe2H][B(C6H5)4] in THF. Complexes 3 and 4 can be converted to cationic species [(L)M(CH2Ph)2]+ by reaction with [PhNMe2H][B(C6F5)4] in C6D5Br in the absence of THF. The neutral complexes 1-4 and their cationic derivatives were studied as catalysts for the hydroamination/cyclization of 2,2-diphenylpent-4-en-1-amine and N-methylpent-4-en-1-amine reference substrates and compared with ligand-free Sc, Y, and La neutral and cationic catalysts. The most effective catalysts in the series were the cationic L-yttrium catalyst (for 2,2-diphenylpent-4-en-1-amine) and the cationic lanthanum systems (for N-methylpent-4-en-1-amine). For the La catalysts, evidence was obtained for release of L from the metal during catalysis.
Synthesis, DFT Studies, and Reactions of Scandium and Yttrium Dialkyl Cations Containing Neutral fac
Yttrium-Alkyl Complexes Supported by a Ferrocene-Based Phosphinimine Ligand
The
synthesis and characterization of two yttrium alkyl complexes
supported by a bisphosphinimine ferrocene ligand, <b>NP</b><sup><b>fc</b></sup> (1,1′-di(2,4-di-<i>tert</i>-butyl-6-diphenylphosphiniminophenoxy)ferrocene), were accomplished.
Although <b>(NP</b><sup><b>fc</b></sup><b>)Y(CH</b><sub><b>2</b></sub><b>Ph)</b> and <b>(NP</b><sup><b>fc</b></sup>)<b>Y(CH</b><sub><b>2</b></sub><b>SiMe</b><sub><b>3</b></sub><b>)</b> could be structurally
characterized, these compounds are thermally sensitive and decompose
at ambient temperature within hours. Their characterization was accomplished
by NMR spectroscopy, electrochemical measurements, and elemental analysis.
Reactivity studies were also carried out; however, the lack of prolonged
thermal stability at ambient temperature of these molecules led to
decomposition before a clean transformation to reaction products could
be observed