Reactions of DNA purines with dirhodium formamidinate compounds that display antitumor behavior
Academic Article
Overview
Identity
Additional Document Info
Other
View All
Overview
abstract
The synthesis and characterization of products from reactions of Rh 2(form) 2(O 2CCF 3) 2(CH 3CN) 2 (form = N,N-p-ditolylformamidinate, N,N-diphenylformamidinate) and the partially solvated [Rh 2(DTolF) 2(CH 3CN) 6][BF 4] 2 (DtolF = N,N-p-ditolylformamidinate) with the DNA purine analogues, 9-ethylguanine, and 9-ethyladenine are described. X-ray crystallography was used to characterize Rh 2(DTolF) 2(O 2CCF 3) 2(CH 3CN) 2 (1) which crystallizes in the space group P2 1/n with a = 10.849 (3) , b = 21.435 (6) , c = 18.677 (3) , V = 4340 3, Z = 4, R = 0.0451, and R w = 0.0904. The two rhodium centers are bridged by four O 2CCF 3- ligands with a Rh-Rh distance of 2.24743(5) . Compound 1 reacts with 9-ethylguanine to form Rh 2(DTolF) 2(9-EtGH) 2(O 2CCF 3) 2 (3) which exists as two isomers, namely head-to-head and head-to-tail as confirmed by 1H NMR spectroscopy. [Rh 2(DTolF) 2(CH 3CN) 6][BF 4] 2 (5) crystallizes in the Pbca space group with a = 21.646 (3) , b = 31.272 (3) , c = 14.561(4) , V = 9857 3, Z = 8, R = 0.046, and R w = 0.063. The Rh-Rh bond distance is 2.5594 (8) . The partially solvated compound 5 reacts with 9-ethyladenine and 9-ethylguanine to form [Rh 2(DTolF) 2(9-EtAH) 2(CH 3CN)][BF 4] 2 (6) and [Rh 2(DTolF) 2(9-EtGH) 2(CH 3CN)][BF 4] 2 (7), respectively. Compound 6 was characterized by X-ray crystallography as well as by variable temperature 1H NMR spectroscopy. [Rh 2(DTolF) 2-(9-EtAH) 2(CH 3CN)][BF 4] 2 crystallizes in the P2 1/c space group with a = 15.648(8) , b= 16.575(5) , c = 20.026(8) , = 105.17(4), V = 4994 3, Z = 4, R = 0.063, and R w = 0.073. This compound contains two bridging DTolF - ligands as well as two 9-ethyladenine ligands, bridging through the N7 and exocyclic N6 positions in a head-to-tail fashion. 1H NMR studies performed on 6 revealed that the N6 position is in the imino (NH -) form. 1999 American Chemical Society.
