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对乙醛烯醇锂在四氢呋喃和四氢呋喃-正已烷混合溶中的动态行为进行了~(13)C和~1H核磁共振和~(13)C自旋-晶格弛豫时间的研究。在这些溶剂中,乙醛烯醇锂能以两种溶剂化程度不同的非刚性四聚体同时存在,两种聚集体间的转换在低温下慢于NMR时标,温度对平衡的影响很小。在溶液中,聚集体整体运动是各向同性的;与此同时,乙烯基在聚集体内作快速内旋转。聚集休整体重取向运动和乙烯基内旋转的势垒分别为8.5±0.7 KJ·mol~(-1)和6.6±1 KJ·mol~(-1)。
The ~ (13) C and ~ 1H nuclear magnetic resonance and ~ (13) C spin-lattice relaxation time were investigated for the dynamic behavior of lithium vinyl ethenohydride in tetrahydrofuran and tetrahydrofuran-n-hexane mixtures. In these solvents, acetaldehyde lithium alcoholate coexists with two non-rigid tetramers with different degrees of solvation. The transition between the two aggregates is slower than the NMR time scale at low temperatures and the effect of temperature on the balance is small . In solution, the aggregate movement is isotropic; at the same time, the vinyl rotates rapidly within the aggregate. The potential barriers for the aggregation reorientation and vinyl rotation were 8.5 ± 0.7 KJ · mol -1 and 6.6 ± 1 KJ · mol -1, respectively.