115  US 9,250,518 B2  116  X  X  X  Herein,  M- is a non-nucleophilic counter ion.  Examples of the non-nucleophilic counter ion  M- include  halide ions such as chloride and bromide ions; fluoroalkyl› sulfonate ions such as triflate, 1, 1, 1-trifluoroethanesulfonate,  and nonafluorobutanesulfonate; arylsulfonate ions such as  tosylate, benzenesulfonate, 4-fluorobenzenesulfonate, and  1,2,3,4,5-pentafluorobenzenesulfonate; alkylsulfonate ions  such as mesylate and butanesulfonate; imides such as bis  (trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)  imide and bis(perfluorobutylsulfonyl)imide; methides such  as tris(trifluoromethylsulfonyl)methide and tris(perfluoroet› hylsulfonyl)methide.  Also included are sulfonates having fluorine substituted at  a-position as represented by the general formula (K-1) and  sulfonates having fluorine substituted at a- and ~-positions as  represented by the general formula (K-2).  In formula (K-1 ), R $^{102 }$is hydrogen, or a straight, branched or  cyclic C$_{1 }$-C$_{20 }$alkyl group, C$_{2}$ -C$_{20 }$alkenyl group, or  CcC$_{20 }$ aryl group, which may have an ether, ester, carbonyl moiety,  lactone ring, or fluorine atom. In formula (K-2), R 103  is  (K-1)  (K-2)  -continued 