It was demonstrated on the basis of reactivity, 1H NMR and CNDO charge distributions that the π-dianions of 9-fluorenone and 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-one were formed from the corresponding neutral precursors in contact with sodium or potassium in dimethoxyethane or tetrahydrofuran at low temperature in vacuo.
根据反应活性、1H NMR和CNDO电荷分布证明,
9-芴酮和
10,11-二氢-5H-二苯并[a,d]环庚烯-5-酮的π-二价阴离子是由相应的中性化合物形成的前体在
二甲氧基乙烷或
四氢呋喃中在低温真空下与
钠或
钾接触。