Patent ID: 8357800

Claim:
A complex of formula (I): wherein: M represents a transition metal having an atomic number of at least 40; E 1 represents an aromatic or heteroaromatic ring optionally condensed with additional aromatic moieties or non aromatic cycles, wherein said ring optionally has one or more substituents and optionally forms a condensed structure with the ring comprising E 2 , and wherein said ring coordinates to metal M by using a Sp 2 hybridized carbon; E 2 represents a N-containing aromatic ring optionally condensed with additional aromatic moieties or non aromatic cycles, wherein said ring optionally has one or more substituents and optionally forms a condensed structure with the ring comprising E 1 , and wherein said ring coordinates to metal M by using a Sp 2 hybridized nitrogen; R′ is the same or different at each occurrence and is selected from the group consisting of —H, —F, —Cl, —Br, —NO 2 , —CN, a straight or branched C 1-20 alkyl, a C 3-20 cyclic alkyl, a straight or branched C 1-20 alkoxy, a C 1-20 dialkylamino, a C 4-14 aryl, and a C 4-14 heteroaryl that is optionally substituted by one or more non aromatic radicals, wherein optionally a plurality of substituents R′, either on the same ring or on two different rings, collectively form an additional mono- or polycyclic ring system, optionally aromatic; X 1 , X 2 , X 3 , X 4 , X 5 and X 6 are the same or different at each occurrence and are independently selected from the group consisting of hydrogen, alkyl, aryl, heteroaryl and alkyl, each of which is optionally substituted by at least one substituent; A − is a counter anion; and n 1 , n 2 , m 1 and m 2 are the same or different at each occurrence and represent an integer from 0 to 4, wherein n 1 +m 1 =4 and n 2 +m 2 =4, provided that n 1 and n 2 are not zero at the same time.