Versatile Reactivity of Scorpionate-Anchored Yttrium-Dialkyl Complexes towards Unsaturated Substrates
Weiyin Yi1, Jie Zhang, Fangjun Zhang
1Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (P. R. China).
Abstract:
A series of unusual chemical-bond transformations were observed in the reactions of high active yttrium-dialkyl complexes with unsaturated small molecules. The reaction of scorpionate-anchored yttrium-dibenzyl complex [Tp(Me2)Y(CH2Ph)2(thf)] (1, Tp(Me2)=tri(3,5-dimethylpyrazolyl)borate) with phenyl isothiocyanate led to C=S bond cleavage to give a cubane-type yttrium-sulfur cluster, {Tp(Me2)Y(μ3-S)}4 (2), accompanied by the elimination of PhN-C(CH2Ph)2. However, compound 1 reacted with phenyl isocyanate to afford a C(sp(3)) H activation product, [Tp(Me2)Y(thf){μ-η(1):η(3)-OC(CHPh)NPh}{μ-η(3):η(2)-OC(CHPh)NPh}YTp(Me2)] (3). Moreover, compound 1 reacted with phenylacetonitrile at room temperature to produce γ-deprotonation product [(Tp(Me2))2Y](+)[Tp(Me2)Y(N=C=CHPh)3](-) (6), in which the newly formed N=C=CHPh ligands bound to the metal through the terminal nitrogen atoms. When this reaction was carried out in toluene at 120 °C, it gave a tandem γ-deprotonation/insertion/partial-Tp(Me2)-degradation product, [(Tp(Me2)Y)2(μ-Pz)2{μ-η(1):η(3)-NC(CH2Ph)CHPh}] (7, Pz=3,5-dimethylpyrazolyl).
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