Linear free-energy relationships between stability parameters of substituted tropylium and cyclopropenylium ions as measured by reduction rate with chromium(II), reduction potential, charge-transfer energy, and pKR values
作者:Kunio Okamoto、Ken'ichi Takeuchi、Koichi Komatsu、Yasuhiro Kubota、Riichiro Ohara、Makoto Arima、Kenji Takahashi、Yoshinori Waki、Shuzo Shirai
DOI:10.1016/s0040-4020(01)90909-3
日期:——
Nine tropylium ions have been synthesized and the empirical stability parameters (i)–(iv) have been measured along with the parameters of known tropylium and cyclopropenylium ions: (I) the Cr(II)-ion reduction rate constant (k2) in 10% aqueous hydrochloric acid at 25.0°; (ii) the charge-transfer frequency (vCTmax) with pyrene in 1,2-dichloroethane; (iii) the reduction peak potential (Ered) in dichloromethane
已经合成了九个对yl离子,并测量了经验稳定性参数(i)-(iv)以及已知的对yl离子和环丙烯鎓离子的参数:(I)Cr(II)离子还原速率常数(k 2) 25.0°的10%盐酸水溶液; (ii)1,在1,2-二氯乙烷中的电荷转移频率(v CT max);(iii)在二氯甲烷或乙腈中的还原峰电位(E red);(iv)在23%的乙醇水溶液,50%的乙醇水溶液和50%的乙腈水溶液中的pK R +值。当检查了这些和先前报告的结果的线性自由能关系(LFER)(a)之间的电荷转移能量(ECT)},119.5× v CT max(cm -1),kJ mol -1和E red (96.36×E red(V),kj mol -1)};(b)在log k 2 (5.70×log k 2(1 mol -1 s -1),kJ mol -1)}与E red之间;(c)在log k 2和E CT之间,发现令人满意的相互关系。