Abstract: The invention provides compounds of the Formula (I), in which W is independently selected from W1, W2, W3, W4, W5, or W represents a pair of substituents independently selected from H, alkyl, aryl or amide in which the amide is optionally part of a linking chain, and the Zn—Zn? bonds (n=4-17; n?=n+1) are optionally of any whole or partial bond order, Y is Y1 or Y represents a pair of substituents independently selected from H, C1-C6 alkyl, Z5 or Z6 aryl, or Y is optionally a bridging structure that may comprise one or more C1-C6 amide, C1-C6 ether, or C1-C6 ester groups, R—R39 are independently selected from no substituent, a lone pair of electrons, H, halogen, C5-C6 aryl, C1-C12 alkyl, amine, C1-C6 alkylamine, C1-C6 amide, nitro, cyano, carboxyl, C1-C6 ester, phosphane, thiol, C1-C6 thioether, OR40, and suitable pairs of adjacent R groups (R—R39) may optionally together form part of a C5 or C6 aryl ring, a Z5 or Z6 ring, R40 is independently selected from H, C1-C6 alkyl, Z5 or Z6 ar

Abstract: The invention provides compounds of the Formula (I), in which W is independently selected from W1, W2, W3, W4, W5, or W represents a pair of substituents independently selected from H, alkyl, aryl or amide in which the amide is optionally part of a linking chain, and the Zn—Zn bonds (n=4-17; n?=n+1) are optionally of any whole or partial bond order, Y is Y1 or Y represents a pair of substituents independently selected from H, C-1-C6 alkyl, Z5 or Z6 aryl, or Y is optionally a bridging structure that may comprise one or more C-1-C6 amide, C-1-C6 ether, or C-1-C6 ester groups, R-R39 are independently selected from no substituent, a lone pair of electrons, H, halogen, C5-C6 aryl, C1- C-12 alkyl, amine, C-1-C6 alkylamine, C-1-C6 amide, nitro, cyano, carboxyl, C-1-C6 ester, phosphane, thiol, C-1-C6 thioether, OR?, and suitable pairs of adjacent R groups (R-R39) may optionally together form part of a C5 or C6 aryl ring, a Z5 or Z6 ring, R? is independently selected from H, C-1-C6 alkyl, Z5 or Z6 aryl, C-1-C6 ester,