Nitrogen-containing aromatic compounds and metal complexes

A compound represented by any of the following general formulas (11)-(20), (22) or (23):

• wherein R11-R20, R22 and R23 are hydrogen or a substituent and each may be the same or different, with adjacent substituents optionally bonding together to form a ring;
• Q11 is a nitrogen-containing aromatic heterocyclic ring and each may be the same or different;
• T12 is bromine atom, chlorine atom or iodine atom and each may be the same or different;
• E13, E20 and E22 each independently represent hydrogen or a protecting group;
• and
• X16 and X17 each independently represent hydrogen or a halogeno group, or the X16 or X17 groups are bonded together as direct bonds.