3'-oh unblocked nucleotides and nucleosides base mdified with non-cleavable, terminating groups and methods for their use in dna sequencing

A compound selected from the group of formulas or salts thereof consisting of:

• wherein R1═H, monophosphate, diphosphate, triphosphate, or alpha-thio-triphosphate,
• R2═H or OH,
• R3 and R4 are each independently selected from the group consisting of H, a C1-C12 straight chain or branched alkyl, a C2-C12 straight chain or branched alkenyl or polyenyl, a C2-C12 straight chain or branched alkynyl or polyalkynyl, and an aromatic group,
• R5, R6, and R7, are each independently selected from the group H, OCH3, NO2, CN, a halide, a C1-C12 straight chain or branched alkyl, a C2-C12 straight chain or branched alkenyl or polyenyl, a C2-C12 straight chain or branched alkynyl or polyalkynyl, and an aromatic group, and/or with the proviso that one of R5, R6 and R7 is a linker group of the general structure —C≡CCH2NH2,
• wherein X═CH2, CH═CH, O, S, or NH,
• Y═CH2, O, or NH,
• n=an integer from 0-12;
• m=an integer from 0-12,
• Dye=a fluorophore,
• and R8 and R9 are as defined above for R5, R6, and R7, with the proviso that R8 and R9 are not NO2.