1. A compound having the structure: 5 R 1 is oxygen or sulfur; R 2 and R 3 are independently selected from the group consisting of —N&boxH;, —CR&boxH;, and —CX&boxH;; M is &boxH;N— or &boxH;CR 4 —, wherein R 4 and R 8 are independently R or together form a single linking moiety linking M to the ring vertex 2′, the linking moiety being selected from the group consisting of a single bond, —CRR′—, —CR&boxH;CR′—, —C(O)—, —O—, —S(O) y —, —NR—, and —N&boxH;; and R 5 and R 7 are independently selected from the group consisting of —(CRR′) n —, —C(O)—, —CR&boxH;CR′—, —CR&boxH;CX—, —CRX—, —CXX′—, —S—, and —O—, and R 6 is selected from the group consisting of —(CRR′) m —, —C(O)—, —CR&boxH;CR′—, —CRX—, —CXX′—, —S—, and —O—; wherein X and X′ are independently selected from —Br, —Cl, —F, —CN, —NO 2, —OR, —SR, —NRR′, —C(O)R, —CO 2 R, or —CONRR′, wherein two groups R or R′ on an individual group X, or on two adjacent groups X, may together form a ring; and R and R′ are independently selected from (i) hydrogen, (ii) C 1 -C 6 branched or unbranched alkyl, which may be unsubstituted or substituted with one or more functionalities selected from halogen, nitro, alkoxy, hydroxy, alkylthio, amino, keto, aldehyde, carboxylic acid, carboxylic ester, or carboxylic amide, and wherein two such alkyl groups on a single carbon or on adjacent carbons may together form a ring, and (iii) aryl, which may be unsubstituted or substituted with one or more functionalities selected from halogen, nitro, alkoxy, hydroxy, aryloxy, alkylthio, amino, keto, aldehyde, carboxylic acid, carboxylic ester, or carboxylic amide; m and p are, independently, 0 or 1; and n and y are, independently, 0, 1 or 2.