A compound having the following structure: (I) wherein Z is -CHOR1R2 or -C(O)R2; R1 is H, an alkyl group, an aryl group, -OC(O)ORa, wherein Ra is an alkyl group, -C(O)Rb wherein Rb is an alkyl group, an aryl group, an alkoxy group, an amino group, an alkylamino group, a dialkylamino group, an aryl amino group, a diarylamino group, an arylalkyl amino group, a protecting group or a fluorous tag; R2 is an alkyl group, an aryl group or an arylalkyl group; R3 is H, an alkyl group, hydroxyalkyl group or an aryl group; R4-R8 are independently the same or different and are hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, an acyloxy group, a haloalkyl group, a perfluoroalkyl group, fluorine, chlorine, bromine, a haloalkyloxy group, a carbamoyloxy group, a hydroxy group, a nitro group, a cyano group, a cyanoalkyl group, an azido group, an azidoalkyl group, a formyl group, a hydrazino group, a hydrazinoalkyl group, a hydroxyalkyl group, an alkoxyalkyl group, -NR1Rm, wherein R1 and Rm are independently hydrogen, an alkyl group, an aryl group, an arylalkyl group, or -C(O)Rb, an aminoalkyl group, an alkylaminoalkyl group, a dialkylaminoalkyl group, an aryl aminoalkyl group, a diarylaminoalkyl group, an arylalkyl aminoalkyl group, -OC(O)ORa, wherein Ra is an alkyl group, -C(O)Rb, -SRC, S(O)Rc or S(O2)Rc wherein Rc is hydrogen, -C(O)Rb, an alkyl group, or an aryl group, (CH2)nSiRdReRf wherein n is an integer within the range of 0 through 10 and Rd, Re and Rf are independently a C1-10 alkyl group, a C2-10 alkenyl group, a C2-10 alkynyl group, an aryl group, a haloalkyl group, a cyanoalkyl group, an azidoalkyl group, a hydrazinoalkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an aminoalkyl group, an alkylaminoalkyl group, a dialkylaminoalkyl group, an aryl aminoalkyl group, a diarylaminoalkyl group, an arylalkyl aminoalkyl group. Alternatively R4 and R5, R6 and R6; R6 and R7; or R7 and R8 can form together a chain of 3 or four groups selected from CH, CH2, O, S, N, NH, N-alkyl or N-aryl. Provided that, at least one of R5-R7 is not H, a lower alkyl group, fluorine, a cyano group, a hydroxyl group, hydroxyalkyl group, an alkoxy group, an aminoalkyl group, an alkylaminoalkyl group, a dialkylaminoalkyl group, an amino group, an alkylamino group, a dialkylamino group, a carbamoyloxy group, a formyl group or -C(O)Rx wherein Rx is an alkyl group.