abstract |
A compound represented by the following formula (1), wherein L is a single bond or a divalent group, and is bonded at any one of the 6 th , 8 th and the 9 th positions indicated by * of 1,10-phenanthroline; Rg is a substituted or unsubstituted benzene ring or a substituted or unsubstituted naphthalene ring; and X is an oxygen atom or N-R 4 . |