Iimveliso

I-N7/O6 i-equatorial ebophelelayo yentsebenziswano ye-antitumor esebenzayo eyinkimbinkimbi Rh (2) (OAc) (4) (H (2) O) (2) (OAc (-) = CH (3) CO (2) (-)) kunye ne-DNA fragment d(GpG) imiselwe ngokungathandabuzekiyo yi-NMR spectroscopy.Ukuqinisekiswa kwangaphambili kwe-X-ray ye-crystallographic ye-head-to-head (HH) kunye ne-head-to-tail (HT) i-adducts ye-dirhodium tetraacetate ene-9-ethylguanine (9-EtGH) ibonise i-bridging engazange ibonwe ngaphambili i-N7 / O6 i-guanine nucleobases ehamba phambili kwi-Rh. -Rh bond.Ukungabikho kwe-N7 protonation kwi-pH ephantsi kunye nokunyuka okuphawulekayo kwi-acidity ye-N1-H (pK(a) malunga ne-5.7 xa kuthelekiswa ne-8.5 ye-N7 kuphela i-adducts ye-platinum ebophelelweyo), ecetyiswa ngokuxhomekeka kwe-pH ye-purine H8 (1 ) H NMR iiresonances zeRh(2)(OAc)(2)(9-EtG)(2) kunye neRh(2)(OAc)(2-)[d(GpG)],ziyahambelana ne bidentate N7/O6 ebophayo iinucleobase zeguanine.Amaxabiso e-pK(a) aqikelelwa kwi-N1-H (de) protonation, ukusuka kufundo lokuxhomekeka kwe-pH ye-C6 kunye ne-C2 (13)C NMR resonances ye-Rh(2)(OAc)(2)(9-EtG)( 2) ii-isomers, ziyavumelana ne-t hose ethathwe kwi-H8 (1)H NMR resonance titrations.Ukuthelekiswa kwe (13) C NMR resonances yeC6 kunye neC2 yedirhodium idducts Rh (2) (OAc) (2) (9-EtG) (2) kunye neRh (2) (OAc) (2)[d (GpG) )] kunye ne-resonances ehambelanayo ye-ligands engabonakaliyo [kwi-pH 7.0 ye-9-EtGH kunye ne-pH 8.0 ye-d (GpG)], ibonisa ukutshintshwa okukhulu kwe-Deltadelta malunga ne-11.0 kunye ne-6.0 ppm ye-C6 kunye ne-C2, ngokulandelanayo;utshintsho lokugqibela lubonisa umphumo we-O6 ebophelelayo kumaziko e-dirhodium kunye nokuphucula okulandelayo kwi-acidity ye-N1-H.I-H8/H8 ROE enzulu i-cross-peaks kwi-spectrum ye-2D ROESY NMR ye-Rh (2) (OAc) (2) [d(GpG)] ibonisa ukulungiswa kwentloko-intloko yeziseko ze-guanine.I-Rh(2)(OAc)(2)[d(GpG)] i-adduct ibonisa iiconformers ezimbini ezinkulu ezisekunene, i-HH1 R kunye ne-HH2 R, kunye ne-HH1 R ibe ninzi ngokuphindwe kathathu kune-HH2 R engaqhelekanga. I-adducts ibonise ukuhlanjululwa kwe-5'-G ye-sugar rings ukuya kwi-C3'-endo (N-type), ukugcinwa kwe-C2'-endo (S-type) conformation ye-3'-G sugar ring gs, kunye ne-anti orientation ngokumalunga iibhondi ze-glycosyl.Iimpawu zolwakhiwo ezifunyenwe kwi-Rh(2)(OAc)(2))[d(GpG)] ngendlela ye-NMR spectroscopy zifana kakhulu nezo ze-cis-[Pt(NH(3)))(2))[d( GpG)]] kunye nokuxhasa izifundo zemodyuli yemolekyuli.