<p>A compound represented by general formula (1) [wherein Ar1 represents a 5- to 20-membered aromatic cyclic residue having a valency of 2 to 10, provided that the aromatic residue may contain a hetero atom and may have a substituent, and the ring that is linked to Ar1 may have a double bond at any position; Xa and Xb independently represent a hetero atom, provided that Xa and Xb may independently have a substituent; R1a and R1b independently represent a monovalent substituent; and n1 represents an integer of 2 to 10.]</p>
