Insertion Chemistry of Cp*zY(2-pyridyl) and Molecular Structure of the Unexpected CO Insertion Product (Cp"2y) 2@ mq 2:q 2-oc (NC 5H4) 2)

摘要: Pyridine is metalated selectively at the 2-position by (Cp*2YH)2 to yield Cp*2Y(2-pyridyl) (1). Compound 1 reacts with H2 give hydride addition product Cp*2Y(NC5H6) (2). With THF and pyridine adducts Cp*2Y(eta2-2-pyridyl)(THF) (3) Cp*2Y(eta1-2-pyridyl)-(py) (4) are formed. The complex 4 not stable higher temperatures, after organic work up a stoichiometric amount of C-C coupling 2,2'-bipyridine obtained. Ethylene propylene react monoinsertion products Cp*2-YCH2CH2(2-NC5H4) (5) Cp*2YCH2CHMe(2-NC5H4) (6). alkynes HCCR, C-H activation form acetylides Cp*2Y(CCR)(py) (7, R = H; 8, Me) dominant reaction. Also 2-butyne observed yielding propargylic metalation Cp*2YCH2CCMe (9). 2-Pentyne gives mixture insertion Cp*2Y(CEtCMe(2-NC5H4)) (10) Cp*2Y(CMeCEt(2-NC5H4)) (11). A surprising reaction CO (Cp*2Y)2(mu-eta2:eta2-OC(2-NC5H4)2) (12) was observed. molecular structure 12 determined X-ray diffraction: Space group P2(1)/c unit cell parameters 14.194(4) angstrom, b 17.559(4) c 18.717(5) beta 109.61(2)degrees, Z 4. Least-squares refinement based on 6867 reflections converged R1 0.09. 5 sigma-bond metathesis 2-ethylpyridine. By using as catalyst, alkylation 2-ethylpyridine possible. minor amounts 2-n-butylpyridine, 2-n-hexylpyridine, polyethylene were formed in this catalytic process. thermally decomposes isomers Cp*2Y(2-NC5H3(6-Et)) (13) Cp*2YCHMe(2-NC5H4) (14) 80-degrees-C (60:40). Attempts convert hydrogenolysis Y-C bond also resulted formation 13 14 (55:45). In an intermediate seems likely because 14.