Metal Complexes

A monometallic metal complex comprising a hexadentate tripodal ligand wherein three bidentate sub-ligands coordinate to a metal and the three bidentate sub-ligands, which are optionally the same or different, are joined via a bridge of formula (1):

• wherein
• the dotted bonds represent the bonds of the three bidentate sub-ligands to this structure;
• X1 is the same or different in each instance and is C, which is optionally substituted, or N;
• X2 is the same or different in each instance and is C, which is optionally substituted, or N;
• or two adjacent X2 groups together are N, which is optionally substituted, O or S, so as to form a five-membered ring;
• or two adjacent X2 groups together are C, which is optionally substituted, or N when one of the X3 groups in the cycle is N, so as to form a five-membered ring;
• with the proviso that not more than two adjacent X2 groups in each ring are N;
• and wherein any substituents optionally define a ring system with one another or with substituents bonded to X1;
• X3 is C in each instance in one cycle or one X3 group is N and the other X3 group in the same cycle is C, wherein the X3 groups in the three cycles are optionally selected independently, with the proviso that two adjacent X2 groups together are C, which is optionally substituted, or N when one of the X3 groups in the cycle is N;
• and
• wherein the three bidentate ligands, apart from via the bridge of formula (1), are optionally ring-closed by a further bridge to form a cryptate.