Synthesis and characterization of ionic liquids containing copper, manganese, or zinc coordination cations
作者:Harry D. Pratt III、Alyssa J. Rose、Chad L. Staiger、David Ingersoll、Travis M. Anderson
DOI:10.1039/c1dt10973a
日期:——
Copper-, manganese-, and zinc-based ionic liquids (CuNH2CH2CH2OH}6[CH3(CH2)3CH(C2H5)CO2]2 (2), CuNH(CH2CH2OH)2}6[CH3(CH2)3CH(C2H5)CO2]2 (3A), CuNH(CH2CH2OH)2}6[CF3SO3]2 (3B), CuNH(CH2CH2OH)2}6[(CF3SO2)2N]2 (3C), MnNH(CH2CH2OH)2}6[CF3SO3]2 (4), and ZnNH2CH2CH2OH}6[CF3SO3]2 (5)) are synthesized in a single-step reaction. Infrared data suggest that ethanolamine preferentially coordinates to the metal center through the amine group in 2 and the hydroxyl group in 5. In addition, diethanolamine coordinates through the amine group in 3A, 3C, and 4 and the hydroxyl group in 3B. The compounds are viscous (>1000 cP) at room temperature, but two (3C and 4) display specific conductivities that are reasonably high for ionic liquids (>20 mS cm−1). All of the compounds display a glass transition (Tg) below −50 °C. The cyclic voltammograms (CVs) of 2, 3A, 3B, and 3C display a single quasi-reversible wave associated with Cu(II)/Cu(I) reduction and re-oxidation while 5 shows a wave attributed to Zn(II)/Zn(0) reduction and stripping (re-oxidation). Compound 4 is the first in this new family of transition metal-based ionic liquids (MetILs) to display reversible Mn(II)/Mn(III) oxidation and re-reduction at 50 mV s−1 using a glassy carbon working electrode.
铜基、锰基和锌基离子液体(CuNH2CH2CH2OH}6[CH3(CH2)3CH(C2H5)CO2]2 (2)、CuNH(CH2CH2OH)2}6[CH3(CH2)3CH(C2H5)CO2]2 (3A)、CuNH(CH2CH2OH)2}6[CF3SO3]2 (3B)、CuNH(CH2CH2OH)2}6[(CF3SO2)2N]2(3C)、MnNH(CH2CH2OH)2}6[CF3SO3]2(4)和 ZnNH2CH2CH2OH}6[CF3SO3]2 (5))都是通过一步反应合成的。红外数据表明,乙醇胺优先通过 2 中的胺基和 5 中的羟基与金属中心配位。 此外,二乙醇胺通过 3A、3C 和 4 中的胺基和 3B 中的羟基与金属中心配位。这些化合物在室温下都很粘稠(>1000 cP),但有两种(3C 和 4)显示出离子液体相当高的比电导率(>20 mS cm-1)。所有化合物的玻璃转化温度(Tg)均低于 -50°C。2、3A、3B 和 3C 的循环伏安图(CV)显示了一个与 Cu(II)/Cu(I) 还原和再氧化相关的单个准可逆波,而 5 则显示了一个归因于 Zn(II)/Zn(0) 还原和剥离(再氧化)的波。化合物 4 是这个新的过渡金属基离子液体(MetILs)家族中第一个使用玻璃碳工作电极在 50 mV s-1 下显示出可逆的 Mn(II)/Mn(III) 氧化和再还原的化合物。