Hydrogen Bonding in the Crystal Structures of New Imidazolium Triflimide Protic Ionic Liquids
作者:Gino Bentivoglio、Alexander Schwärzler、Klaus Wurst、Volker Kahlenberg、Gerhard Nauer、Günther Bonn、Herwig Schottenberger、Gerhard Laus
DOI:10.1007/s10870-009-9554-8
日期:2009.9
The synthesis and crystal structures of 1,3-diamino-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (1), 1,3-dihydroxy-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (2) and 1-(2-(diethylammonio)ethyl)-3-methylimidazolium bis(bis(trifluoromethylsulfonyl)imide) (4) are reported. The salts 1, 2 and 4 have melting points below 100 °C, the intermediate 1-(2-(diethylamino)ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (3) is liquid at room temperature. Compound 1 is monoclinic, space group P21/n with a = 8.4979(4) Å, b = 12.2803(6) Å, c = 13.9400(7) Å, β = 93.086(4)°, and Z = 4. Compound 2 is monoclinic, space group P21/c with a = 7.6165(2) Å, b = 20.5323(8) Å, c = 9.7654(3) Å, β = 111.046(2)°, and Z = 4. Compound 4 is triclinic, space group $$ P\overline1} $$ with a = 8.5313(4) Å, b = 9.2157(4) Å, c = 20.5812(8) Å, α = 84.668(2)°, β = 83.738(2)°, γ = 63.096(2)°, and Z = 2. The ions in 1 build a network of N–H···O hydrogen bonds, in 2 they are linked to chains by O–H···N and bifurcated O–H···O hydrogen bonds, whereas in 4 they form pairs by N–H···O contacts. The triflimide anions adopt transoid conformations. Short interionic contacts, conformational flexibility, and disorder phenomena were identified in the crystal structures of three new, low-melting, protic imidazolium triflimides.
报道了1,3-二氨基-2-甲基咪唑鎓双(三氟甲基磺酰)亚胺(1)、1,3-二羟基-2-甲基咪唑鎓双(三氟甲基磺酰)亚胺(2)和1-(2-(二乙氨基)乙基)-3-甲基咪唑鎓双(双(三氟甲基磺酰)亚胺)(4)的合成及其晶体结构。盐1、2和4的熔点均低于100°C,中间体1-(2-(二乙氨基)乙基)-3-甲基咪唑鎓双(三氟甲基磺酰)亚胺(3)在室温下为液体。化合物1为单斜晶系,空间组P21/n,a = 8.4979(4) Å,b = 12.2803(6) Å,c = 13.9400(7) Å,β = 93.086(4)°,Z = 4。化合物2为单斜晶系,空间组P21/c,a = 7.6165(2) Å,b = 20.5323(8) Å,c = 9.7654(3) Å,β = 111.046(2)°,Z = 4。化合物4为三斜晶系,空间组$$ P\overline1} $$,a = 8.5313(4) Å,b = 9.2157(4) Å,c = 20.5812(8) Å,α = 84.668(2)°,β = 83.738(2)°,γ = 63.096(2)°,Z = 2。化合物1中的离子形成N–H···O氢键网络,在化合物2中,离子通过O–H···N和分叉的O–H···O氢键连接成链,而在化合物4中则通过N–H···O接触形成对。三氟磺酰亚胺阴离子采用反式构象。在这三种新的低熔点质子性咪唑鎓三氟磺酰亚胺的晶体结构中,识别出了短离子间接触、构象灵活性和无序现象。