A Discrete Self-Assembled Metal Array in Artificial DNA

Abstract

DNA has a structural basis to array functionalized building blocks. Here we report the synthesis of a series of artificial oligonucleotides, d(5′-G H n C-3′) ( n = 1 to 5), with hydroxypyridone nucleobases ( H ) as flat bidentate ligands. Right-handed double helices of the oligonucleotides, n Cu 2+ ·d(5′-G H n C-3′) 2 ( n = 1 to 5), were quantitatively formed through copper ion (Cu 2+ )–mediated alternative base pairing ( H -Cu 2+ - H ), where the Cu 2+ ions incorporated into each complex were aligned along the helix axes inside the duplexes with the Cu 2+ -Cu 2+ distance of 3.7 ± 0.1 angstroms. The Cu 2+ ions were coupled ferromagnetically with one another through unpaired d electrons to form magnetic chains.