Iodine-containing compound

A compound represented by formula (3):

• wherein
• X1 is an n1-valent siloxane group;
• R21 is H, F, Cl, CH3, CF3, or O(CF2)p3F;
• R22 is —R26—OCO— wherein R26 is bonded to X1;
• R23 is H or F;
• R24 is H, F, an aryl group, —COOR30, or an alkyl group optionally substituted with fluorine;
• R25 is H, F, an aryl group, —COOR30, or an alkyl group optionally substituted with fluorine;
• R26 is a single bond or an alkylene group optionally substituted with fluorine;
• R30 is H or an alkyl group;
• p3 is an integer of 1 to 10;
• and
• n1 is an integer of 1 to 10,
• wherein the siloxane group is represented by the following formula:
• —(SiR272—O)q—SiR272—,
• —SiR28rR293-r, or
• (RaSiO1.5)t
• wherein
• R27, each independently at each occurrence, is a hydrogen atom or an alkyl group;
• R28, each independently at each occurrence, is —O—(SiR272—O)s—SiR273—;
• R29 is a single bond;
• Ra, each independently at each occurrence, is Rb or Rc, provided that
• at least one Ra is Rb,
• Rb is a single bond, and
• Rc is a hydrogen atom or alkyl;
• q is an integer of 1 to 20;
• r is an integer of 1 to 3;
• s is an integer of 0 to 20;
• and
• t is any integer.