Oct. 21, 2010  43  US 2010/0266955 Al  [Chemical Formula 42]  (1-5)  (1-6)  [0351]  Among the aforementioned examples, as the cation  moiety for the component (B 1 ), a cation represented by gen› eral formula (I-1) or (I-5) is preferable, and a cation repre› sented by any one of formulas (I-1-1) to (I-1-10) and (I-5-1)  to (I-5-4) shown below is particularly desirable. Among  these, a cation having a triphenyl skeleton, such as a cation  represented by any one of formulas (I-1-1) to (1-1-8) shown  below is particularly desirable.  [0352]  In formulas (I-1-9) and (I-1-10), each ofR$^{8 }$and R 9  independently represents a phenyl group or naphthyl group  which may have a substituent, an alkyl group of 1 to 5 carbon  atoms, an alkoxy group or a hydroxy group.  [0353]  u is an integer of 1 to 3, and most preferably 1 or 2.  [Chemical Formula 43]  (1-1-1)  (1-1-2)  (1-1-3)  In the formulas, R $^{4}$a represents a hydrogen atom or an alkyl  group; R$^{41 }$represents an alkyl group, an acetyl group, a car› boxy group or a hydroxyalkyl group; each of R$^{42 }$to R 46  independently represents an alkyl group, an acetyl group, an  alkoxy group, a carboxy group, or ahydroxyalkyl group; each  of Ila to n$_{5 }$ independently represents an integer of 0 to 3,  provided that  Ila+ n $_{1 }$is 5 or less; and n$_{6 }$represents an integer of  0  to 2.  [0340]  In general formulas (I-5) and (1-6), with respect to  R$^{4}$a to R 46 , the alkyl group is preferably an alkyl group of 1 to  5 carbon atoms, more preferably a linear or branched alkyl  group, and most preferably a methyl group, all ethyl group, a  propyl group, an isopropyl group, an n-butyl group or a tert  butyl group.  [0341]  The alkoxy group is preferably an alkoxy group ofl  to 5 carbon atoms, more preferably a linear or branched  alkoxy group, and most preferably a methoxy group or ethoxy  group.  [0342]  The hydroxyalkyl group is preferably the aforemen› tioned alkyl group in which one or more hydrogen atoms have  been substituted with hydroxy groups, and examples thereof  include a hydroxymethyl group, a hydroxyethyl group and a  hydroxypropyl group.  [0343]  If  there axe two or more of the OR $^{4}$a group, as  indicated by the value of na, then the two or more of the OR $^{4}$a  group may be the same or different from each other.  [0344]  If  there are two or more of an individual R$^{41 }$to R 46  group, as indicated by the corresponding value of n$_{1 }$ to n$_{6}$ ,  then the two or more of the individual R$^{41 }$to R$^{46 }$group may  be the same or different from each other.  [0345]  Ila is preferably 0 or 1.  [0346]  n$_{1 }$ is preferably Oto 2.  [0347]  It is preferable that n$_{2 }$ and n$_{3 }$ each independently  represent 0 or 1, and more preferably 0.  [0348]  n$_{4 }$ is preferably Oto 2, and more preferably 0 or 1.  [0349]  n$_{5 }$ is preferably 0 or 1, and more preferably 0.  [0350]  n$_{6 }$ is preferably 0 or 1.  (1-1-4) 