Aryl compounds for application in a highly polar solvent

A polymer compound comprising a structure represented by Formula (1) as a constitutional unit:

• wherein:
• Ar1, Ar2, Ar3, and Ar4 each independently represent a divalent aromatic group optionally having substituent(s) and may be bonded to each other to form a ring, when more than one Ar2 is present, such Ar2s may be the same as or different from each other, and when more than one Ar4 is present, such Ar4s may be the same as or different from each other;
• Ar5 represents a monovalent aromatic group optionally having substituent(s), and when more than one Ar5 is present, such Ar5s may be the same as or different from each other;
• p and q each independently represent an integer of 0 or more;
• and
• R1 represents a monovalent group represented by Formula (2), and when more than one R1 is present, such R1s may be the same as or different from each other:
• wherein:
• R2 represents a (1+n1+n4)-valent aromatic group optionally having substituent(s);
• R3 represents a divalent organic group optionally having substituent(s);
• R4 represents a divalent organic group comprising a structure which is capable of interacting with a cation through chelation, and when more than one R4 is present, such R4s may be bonded to each other to form a ring;
• R5 is an optionally substituted monovalent organic group remaining after removing one hydrogen atom from a compound represented by a formula selected from the group consisting of formulas 3-1 to 3-4 and 3-6 to 3-27, and when more than one R5 is present, such R5s may be bonded to each other to form a ring:
• Y1 represents a monovalent group comprising an anion;
• n1 represents 1 or 2, n2 represents 0 or 1, n3 represents an integer of 0 or more, n4 represents an integer of 1 or more, and n1+n3≧1 is satisfied,
• when more than one R3 is present, such R3s may be the same as or different from each other, when more than one R4 is present, such R4s may be the same as or different from each other, when more than one R5 is present, such R5s may be the same as or different from each other, and when more than one Y1 is present, such Y1s may be the same as or different from each other;
• M1 represents a cation;
• Z1 represents an anion;
• a represents an integer of 1 or more, and b represents an integer of 0 or more, provided that a and b are selected so that electric charge of the structure represented by Formula (1) becomes zero;
• and
• when more than one M1 is present, such M1s may be the same as or different from each other, and when more than one Z1 is present, such Z1s may be the same as or different from each other.