David P. Smith, E. Kohen, M. Maestre
Sep 15, 1993
Citations
0
Influential Citations
29
Citations
Journal
Inorganic Chemistry
Abstract
The reactions of adenosine 5'-monophosphate (5'-AMP) in water (pH 5-8) with a ([eta]-pentamethylcyclopentadienyl)rhodium aqua complex, [CpRh(H[sub 2]O)[sub 2](OTf)[sub 2]][sub x] (1), showed, by [sup 1]H and [sup 31]P NMR spectroscopy, that the 5'-P(O)[sub 2]=O group significantly inhibited cyclic trimer formation, [CpRh([mu]-[eta][sup 2](N6,N7)-5'-AMP)][sub 3], via competition with N1 and NH6 for the CpRh site and, as well, provided other mononuclear and dinuclear Cp[sup *]Rh-O-P complexes. In contrast, both the phosphate methyl ester of 5'-AMP and 3'-AMP exclusively formed the cyclic trimer structures [CpRh([mu]-[eta][sup 1](N1):[eta][sup 2](N6,N7)-methyl-5'/3'-AMP)][sub 3]. The consequence of steric effects, as demonstrated by the position and substitution of the phosphate group attached to the ribose, on the diastereoselectivity of cyclic trimer formation, as observed by [sup 1]H and [sup 31]P NMR spectroscopy and circular dichroism analysis over time, shows that the phosphate methyl ester of 5'-AMP provides a greater diastereoselectivity (6:1) after 1 week of equilibration compared to 5'-AMP (1.5:1) and 3'-AMP (1.2:1).