Patent ID: 8357799

Claim:
A neutral complex of formula: wherein: M represents a transition metal of atomic number of at least 40; E 1 represents an aromatic or heteroaromatic ring, optionally condensed with additional aromatic moieties or non aromatic cycles, said ring optionally having one or more substituents, optionally forming a condensed structure with the ring comprising E 2 , said ring coordinating to the metal M via a sp 2 hybridized carbon; E 2 represents a N-containing aromatic ring, optionally condensed with additional aromatic moieties or non aromatic cycles, said ring optionally having one or more substituents, optionally forming a condensed structure with the ring comprising E 1 , said ring coordinating the metal M via a sp 2 hybridized nitrogen; and X 1 and X 2 are same or different at each occurrence and are independently selected from the group consisting of alkyl, aryl, heteroaryl, and alkyl, each of which is optionally substituted by at least one substituent, wherein the phosphino group and the carboxylate moiety illustrated in Formula (I) are separated by one, two, or three carbon atoms.