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In the formulas, R 21 , Y 1 and M+ are the same as defined above; R$^{22 }$represents an aliphatic group which may have an aromatic group as a substituent; and M+ represents an alkali metal ion. 

[0404] As M+, the same alkali metal ions as those described above for M+ can be used. 

[0405] In formula (1-1), R$^{22 }$represents an aliphatic group which may have an aromatic group as a substituent. 

[0406] The aliphatic group may be either a saturated ali› phatic group, or an unsaturated aliphatic group. Further, the aliphatic group may be linear, branched or cyclic, or a com› bination thereof. 

[0407] The aliphatic group may be either an aliphatic hydrocarbon group consisting of carbon atoms and hydrogen atoms, a group in which part of the carbon atoms constituting the aforementioned aliphatic hydrocarbon group have been substituted with a hetero atom-containing substituent, or a group in which part or all of the hydrogen atoms constituting the aforementioned aliphatic hydrocarbon group have been substituted with a hetero atom-containing substituent. 

[0408] As the hetero atom, there is no particular limitation as long as it is an atom other than carbon and hydrogen. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom and a bromine atom. 

[0409] The hetero atom-containing substituent may consist of a hetero atom, or may be a group containing a group or atom other than a hetero atom. 

[0410] Specific examples of the substituent group for sub› stituting part of the carbon atoms include ---0-, -C(=O)---0-, ----C(=O)-, ---O-C(=O)---0-, -C(=O)-NH-, -NH- (the H may be replaced with a substituent such as an alkyl group or an acyl group), -S-, -S(=O)$_{2}$ - and -S(=O)$_{2}$-O-. When the aliphatic hydrocarbon group contains a cyclic group, the aliphatic hydrocarbon group may contain these substituent groups in the ring structure of the cyclic group. 

[0411] Examples of the substituent group for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (=0), ----COOR 96 , -OC(=O)R $^{97 }$and a cyano group. 

[0412] The aforementioned alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group or tert-butoxy group, and most pref› erably a methoxy group or an ethoxy group. 

[0413] Examples of the aforementioned halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable. 

[0414] Example of the aforementioned halogenated alkyl group includes a group in which part or all of the hydrogen atoms within an alkyl group of 1 to 5 carbon atoms (e.g., a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group) have been substituted with the aforementioned halogen atoms. 

-continued 

(1-3) 

[0415] Each of R 96 and R 97 independently represents a hydrogen atom or a linear, branched or cyclic alkyl group of 1 to 15 carbon atoms. 

[0416] When the alkyl group for R$^{96 }$and R$^{97 }$is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5, and still more preferably 1 or 2. Specific examples of alkyl groups include the same groups as those for the linear or branched monovalent saturated hydro› carbon group described below. 

[0417] When the alkyl group for R$^{96 }$and R$^{97 }$is a cyclic group, it may be either a monocyclic group or a polycyclic group. The cyclic group preferably has 3 to 15 carbon atoms, more preferably 4 to 12, and still more preferably 5 to 10. Specific examples of cyclic groups include the same groups as those for the cyclic monovalent saturated hydrocarbon group described below. 

[0418] As the aliphatic hydrocarbon group, a linear or branched saturated hydrocarbon group of 1 to 30 carbon atoms, a linear or branched unsaturated hydrocarbon group of 2 to 10 carbon atoms, or a cyclic aliphatic hydrocarbon group ( aliphatic cyclic group) of3 to 30 carbon atoms is preferable. 

[0419] The linear saturated hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 15, and most preferably 1 to 10. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptade› cyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group and a docosyl group. 

[0420] The branched saturated hydrocarbon group prefer› ably has 3 to 20 carbon atoms, more preferably 3 to 15, and most preferably 3 to 10. Specific examples include a 1-meth› ylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-me› thylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methyl› pentyl group and a 4-methylpentyl group. 

[0421] The unsaturated hydrocarbon group preferably has 2 to 5 carbon atoms, more preferably 2 to 4, and most pref› erably 3. Examples of linear monovalent unsaturated hydro› carbon groups include a vinyl group, a propenyl group (an ally! group) and a butynyl group. Examples of branched monovalent unsaturated hydrocarbon groups include a 1-me› thylpropenyl group and a 2-methylpropenyl group. 

[0422] Among the above-mentioned examples, as the unsaturated hydrocarbon group, a propenyl group is particu› larly desirable. 

[0423] The aliphatic cyclic group may be either a monocy› clic group or a polycyclic group. The aliphatic cyclic group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, still more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. As the aliphatic cyclic group, a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane such as a bicy› cloalkane, tricycloalkane or tetracycloalkane can be used. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobor› nane, tricyclodecane or tetracyclododecane. 

