A facile route to functionalised, protic and chiral ionic liquids based on the triaminocyclopropenium cation

Owen J. Curnow, Michael T. Holmes, Leonardus C. Ratten, Kelvin J. Walst, Ruhamah Yunis
2012 RSC Advances  
5 Supplmentary material General procedures All reagents and solvents were obtained from commercial sources. Liquid reagents and solvents were typically distilled under a dinitrogen atmosphere prior to use. All operations were performed using standard Schlenk techniques with a dinitrogen atmosphere in order to 10 reduce exposure to water. 1 H-and 13 C{ 1 H}-NMR spectra were collected on a Varian Unity-300 operating at 300 and 75 MHz respectively, or on a Varian INOVA-500 operating at 500 and 126
more » ... ting at 500 and 126 MHz respectively, in CDCl 3 DSC was performed on a Perkin Elmer Q100. Samples of mass 5-20 mg were sealed in a vented aluminium 15 pan and placed in the furnace with a 50 mL/min nitrogen stream; the temperature was raised at 10 °C/min. , referenced to residual solvent peaks. Viscosities were measured on a Brookfield-Wells cone-and-plate viscometer operating at 0.005 -0.2 s -1 TGA data were collected on dried samples using a TA Instruments SDT Q600 at 10 °C/min after further drying at 100 °C for one hour in the instrument. 20 rotation speed range. Electrospray mass spectrometry was carried out on a Micromass LCT, with samples dissolved in acetonitrile. Water contents were determined by Karl Fischer titration using a Metrohm 831 KF coulometer. Chloride contents were determined using a AutolabEco Chemie, with associated GPES software, under a dinitrogen atmosphere. The electrodes were either a glassy carbon (3 mm diameter) or platinum (1 mm 25 diameter) working electrode, a platinum wire counter electrode and a silver reference electrode. Electronic Supplementary Material (ESI) for RSC Advances This journal is Bis(diethylamino)cyclopropenone, (Et 2 N) 2 C 3 KOH (300 g) was dissolved into water (4 L). Tris(diethylamino)cyclopropenium chloride (42 g, 0.15 mol) was added to the solution, and heated to 70 °C for 18 h. Organic compounds were extracted from aqueous 5 solution using CH O 2 Cl 2 (3 x 250 mL). CH 2 Cl 2 removed in vacuo and neutralized using a small amount of HCl. Ethanol (25 mL) added to allow filtering to remove an insoluble impurity, followed by removal of the ethanol in vacuo. Addition of acetone (75 mL) precipitated KCl, which was filtered off. Acetone was removed in vacuo, yielding a dark orange liquid (22 g, 77%). 1 H NMR (300 MHz, CDCl 3 ): δ 3.21 (q, 3 J HH = 7.2 Hz, 8H, NCH 2 CH 3 ), 1.20 (t, 3 J HH = 7.2 Hz, 12H, NCH 2 CH 3 ). 13 C NMR (75 MHz, CDCl 3 ): δ 133.74 10 (CO), 119.32 (C 2 ), 46.01 (NCH 2 CH 3 ), 14.18 (NCH 2 CH 3 ). General preparation of methylsulfate triaminocyclopropenium salts from cyclopropenone Triaminocyclopropenium methylsulfate salts were prepared from the respective diaminocyclopropenone. The cyclopropenone was dried, typically by using an iso-propanol or ethanol azetrope. Dimethylsulfate was 15 added while under a dry, inert atmosphere, and the solution was then stirred for approximately 1 h. An excess of a primary or secondary amine was then added, and the mixture was stirred for a further 1 h. Excess amine was removed by washing with diethylether or petroleum ether and ammonium salts were removed by water-chloroform extractions. (1) Bis(diethylamino)dimethylaminocyclopropenium methylsulfate, [C 3 (NEt 2 ) 2 (NMe 2 )]MeSO Cyclopropenone (Et 4 20 2 N) 2 C 3 O (8.91 g, 45.5 mmol), Me 2 SO 4 (8.60 g, 68.2 mmol) and HNMe 2 (6.80 g, 150 mmol) were reacted as described in the general synthetic procedure and gave a yellow liquid (5.72 g, 37.6%). 1 H NMR (300 MHz, CDCl 3 ): δ 3.68 (s, 3H, MeSO 4 ), 3.40 (q, 3 J HH = 7.3 Hz, 8H, NCH 2 CH 3 ), 3.17 (s, 6H, NCH 3 ), 1.27 (t, 3 J HH = 7.2 Hz, 12H, NCH 2 CH 3 ). 13 C NMR (126 MHz, CDCl 3 ): δ 117.83 (C 1 ), 116.31 (C 2 ), 54.02 (CH 3 SO 4 ), 47.28 (NCH 2 CH 3 ), 42.07 (CH 3 ), 14.07 (NCH 2 CH 3
doi:10.1039/c2ra22078d fatcat:pujrwr73xbdefmvktglqgtbhn4