Imikhiqizo

Ukusebenzisana okubophezela kwe-N7/O6 kwenkabazwe kwe-antitumor esebenzayo eyinkimbinkimbi Rh(2)(OAc)(4)(H(2)O)(2) (OAc(-) = CH(3)CO(2)(-)) nge-DNA fragment d(GpG) inqunywe ngokusobala yi-NMR spectroscopy.Izinqumo zangaphambilini ze-X-ray ze-crystallographic ze-head-to-head (HH) kanye ne-head-to-tail (HT) ye-dirhodium tetraacetate ene-9-ethylguanine (9-EtGH) yembula ukubhuloho okungakaze kubonwe ngaphambili kwe-N7/O6 guanine nucleobases ehlanganisa i-Rh -Rh ibhondi.Ukungabikho kwe-N7 protonation ku-pH ephansi kanye nokwenyuka okuphawulekayo kwe-acidity ye-N1-H (pK(a) cishe engu-5.7 uma kuqhathaniswa no-8.5 kuma-adducts e-platinum eboshwe nge-N7 kuphela), okuphakanyiswe ukuncika kwe-pH ye-purine H8 (1 )Amaresonance e-H NMR ye-Rh(2)(OAc)(2)(9-EtG)(2) kanye ne-Rh(2)(OAc)(2-)[d(GpG)],ahambisana nokubophezela kwe-bidentate N7/O6 ama-nucleobase e-guanine.Amanani e-pK(a) alinganiselwe ku-N1-H (de) protonation, kusukela ezifundweni zokuncika kwe-pH ze-C6 ne-C2 (13)C NMR resonances ye-Rh(2)(OAc)(2)(9-EtG)( 2) ama-isomers, avumelana ne-t hose ethathwe ku-H8 (1)H NMR resonance titrations.Ukuqhathaniswa kwe-(13)C NMR resonances ye-C6 ne-C2 ye-dirhodium adducts Rh(2)(OAc)(2)(9-EtG)(2) kanye ne-Rh(2)(OAc)(2)[d(GpG) )] nama-resonance ahambisanayo wama-ligands angaboshiwe [ku-pH 7.0 ku-9-EtGH kanye ne-pH 8.0 ye-d(GpG)], ibonisa ukuguquguquka okukhulu kwenkundla ye-Deltadelta cishe ku-11.0 no-6.0 ppm ku-C6 ne-C2, ngokulandelana;amashifu okugcina abonisa umphumela wokubophezela kwe-O6 ezikhungweni ze-dirhodium kanye nokuthuthukiswa okulandelayo kwe-asidi ye-N1-H.Iziqongo eziqinile ze-H8/H8 ROE ku-spectrum ye-2D ROESY NMR ye-Rh(2)(OAc)(2)[d(GpG)] zibonisa ukuhlelwa kwekhanda kuya kwekhanda kwezisekelo ze-guanine.Isikhangiso se-Rh(2)(OAc)(2)[d(GpG)] sibonisa izifanisi ezimbili ezinkulu ezingakwesokudla, i-HH1 R ne-HH2 R, ne-HH1 R ibe ngobuningi ngokuphindwe kathathu kune-HH2 R engajwayelekile. ama-adducts aveze ukuphikiswa kwamasongo kashukela angu-5'-G ku-C3'-endo (N-uhlobo), ukugcinwa kwe-C2'-endo (S-type) conformation ye-3'-G sugar ring gs, kanye ne-anti orientation ngokuphathelene amabhondi e-glycosyl.Izici zesakhiwo ezitholakalele i-Rh(2)(OAc)(2))[d(GpG)] kusetshenziswa i-NMR spectroscopy zifana kakhulu nalezo ze-cis-[Pt(NH(3))(2)))[d( GpG)]] futhi iqinise izifundo zokumodela zamangqamuzana.