We have synthesized two novel phosphoramidites with a ferrocenyl moiety at
the 2 ' -ribose position linked through a butoxy linker. Using automated DN
A/RNA synthesis techniques, oligonucleotides containing ferrocene at variou
s positions were prepared and characterized by HPLC,, MALDI-TOF mass spectr
ometry, and electrochemistry. Thermal stability studies of the ferrocene-mo
dified DNA duplexes revealed that introduction of one or two ferrocenyl com
plexes does not result in an observed change of the T-m values of the corre
sponding DNA duplexes when compared to the nonmodified hybrids. These data
indicate that the introduction of a ferrocenyl group at the 2 ' -position o
f the ribose ring containing either a purine or pyrimidine base has no effe
ct on the stability of the modified DNA. The electrochemical behavior of th
e ferrocene-containing DNA was examined by cyclic voltammetry. The modified
2 ' -ferrocene-oligonucleotides are electrochemically active and can be us
ed as signaling probes for the electronic detection of nucleic acids on bio
electronic sensors.