Mass spectrometric study of dirhenium biscarboxylate:purine dinucleotide complexes.

Dirhenium adducts of purine dinucleotides were identified by mass spectrometry. In consecutive studies, Re(2)(O(2)C(2)H(3))(2)Cl(4) . 2H(2)O was reacted with 2'-deoxyguanylyl(3'-->5')-2'-deoxyguanosine (dGpG) and 2'-deoxyadenylyl(3'-->5')-2'-deoxyguanosine (dApG) in H(2)O or D(2)O. These reactions were monitored to identify novel dinuclear rhenium:dinucleotide complexes as confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation tandem mass spectrometry (CID MS/MS) experiments. However, the most abundant adducts detected by ES-MS were dirhenium:nucleotide species. Of these, guanine-containing ions were observed with highest ion counts suggesting a preference for guanine coordination. Dimetal adducts showed coordination of the purine bases and common metalated fragments were observed for both dGpG and dApG reactions.

Tris(1,9-diethyladeninium) triiodide diiodide.

X-ray analysis of the title compound reveals three crystallographically distinct cations of 1,9-diethyladeninium, two iodide anions and one triiodide anion in the asymmetric unit, giving six residues and the formula 3C9H14N5+.I3-.2I-. Standard purine nomenclature is used to identify the atoms of each adenine moiety. Hydrogen bonding is observed between atoms N6 and N7 of a pair of cations [N...N=2.885 (4)/2.902 (3) and 2.854 (3)/2.854 (3) A], with additional hydrogen bonding to I- anions via the other N6 H atom [N...I=3.708 (3), 3.738 (3) and 3.638 (3) A]. The triiodide anion is not involved in hydrogen bonding. The bond lengths and angles of the 1,9-diethyladeninium cations are compared with literature values and confirm the formation of the imine tautomer.