PHOTOREACTIVE COMPOUNDS AND COMPOSITIONS

The present invention provides a compound of formula (I): PtIV(N3)2X1X2Y1Y2, wherein X1 and X2 are the same or different and each one is a group NR1R2R3 wherein R1, R2 and R3 are the same or different and each can be any one of H and optionally substituted alkyl, aryl, aralkyl, acyl, cycloalkyl, heterocyclyl, alkenyl, aralkenyl, alkinyl, cycloalkenyl, or X1 and X2 together represent a group R1R2NR4NR1R2 wherein R1 and R2 have the same meaning as before, and R4 represents an optionally substituted divalent, saturated or unsaturated, alkyl chain, an optionally substituted divalent, saturated or unsaturated cycloalkyl or an optionally substituted divalent aryl, or R4 or two or more of R1, R2, R3 and R4 and the respective N atom(s) to which they are linked, represent an optionally substituted heterocyclyl having at least one ring containing said N atom(s); and Y1 and Y2 are the same or different or when cis together represent a divalent moiety Y3, wherein at least one of Y1 and Y2, or Y3, is a substantially labile ligand in the analogous Pt(II) complex without the azide groups, whilst being substantially resistant, in vivo, to hydrolysis and physiological reducing agents. One or more of R1, R2, R3 and R4, may further represent a covalently bonded link to at least one further complex of formula (I) to form a dimer or oligomer, or to a targeting moiety having affinity for a predetermined tissue or cell type.