An FT-ir study of cis study of trans-dichlorodiammineplatinum(II) bound to inosine-5′-monophosphate

Abstract

Inosine-5'-monophosphate disodium salt (5'-IMPNa,) reacts with cis-dichlorodiammineplatinum(II) (cis-DDP) and its trans-isomer (trans-DDP) to give complexes of the type cis-and trans-Pt(NH3),(IMPNaZ),,CIZ.xHfi, n = 1 or 2 and Pt(lMPNa2),,C12.xH20, where n = 1, 2, or 3 and x = 0-6. In the 1 : 2 platinum complexes the nucleotide binds only to the N7-atom of the purine ring system, while in the I : 1 metal complexes there is indication for Pt-carbonyl interaction (bridging or chelation) in addition to the N7-bonding at neutral pH values with cis-DDP.Solution FT-ir studies (HZO and D,O) showed that the 1 : 1 species formed with cis-DDP at neutral pH's behaved differently from those with trans-DDP. The carbonyl stretching vibration of the free base at 1685 cm-' (HzO) and 1670 cm-' (D20) exhibited marked spectral changes in intensity, shifting, and shape upon complexation, whereas the reaction with the trans-isomer produced only slight perturbations in the above region. IntroductionSince the discovery of the antitumor activity of cis-DDP and other related platinum compounds (I), which seem to bind DNA in tumor cells (2), several attempts have been made (2-7) to explain the mechanism of action of cis-DDP in vitro and in vivo. The N7-bonding of mononucleotides (GMP, IMP, and AMP) to the cis-DDP and other metals has been reported both in solid state and in solutions (8). However, the possibility of a direct metal-carbonyl interaction, in addition to N7-bonding, has been the subject of a long controversy (8, 9). It has been suggested (2) that the effectiveness of the platinum antitumor agent is based on the interaction of the drug with the guanine bases at N7 in the GC pairs (7, 10, 1 1) in nucleic acids and also on the interaction with the O6 of the carbonyl group of guanine (12, 13). Such an interaction could lead to deprotonation of NI of the guanine residue and eventually lead to a mispairing of guanine with thymine and finally cause the cell death (2, 13c). Several attempts have been made (12)(13)(14) to demonstrate the direct metal-carbonyl coordination in addition to the N7-bonding; however, no crystallographic evidence could be obtained. Recently, the structural analysis of a series of platinum blue compounds containing DNA components (uracil and thymine derivatives) showed (15-17) direct metal-carbonyl bonding as well as Pt-nitrogen interaction (bridging). Bau et al. have recently analysed (18) the crystal

Synthesis and structural characteristics of metal–acyclovir (ACV) complexes: [Ni(or Co)(ACV)2(H2O)4]Cl2·2ACV, [Zn(ACV)Cl2(H2O)], [Cd(ACV)Cl2]·H2O and [{Hg(ACV)Cl2}x]. Recognition of acyclovir by Ni–ACV

“…The 1634 cm Ϫ1 band related to δ(NH 2 ) is not appreciably shifted for 1, 2, 4 and 5, although for 3 it is shifted to 1651 cm Ϫ1 , possibly due to the double interaction of the NH 2 group present 8)-N (7)] and these variations, related to the fivemembered ring, have been observed in the spectra of several structurally known N( 7)-metallated complexes. 23,25 The far-IR spectra of the complexes show a new band at 312 1 and 313 cm Ϫ1 2 assigned as essentially ν(M-N). 26 The low frequency band at 332 cm Ϫ1 , found for compound 3, may be attributed to the Zn-Cl stretching mode of the terminal chlorides.…”

“…The IR spectra of the obtained complexes were compared with that of acyclovir. 23,24 The more relevant features are: (a) shift to lower frequencies of the strong band at 1718 cm Ϫ1 (1682, 1670 for 1; 1683, 1669 for 2; 1690 for 3; 1676 for 4 and 1694, 1666 cm Ϫ1 for 5) which is assigned to the vibration ν [C(6)᎐ ᎐ O( 6)] in free ACV. This is consistent with the C᎐ ᎐ O group involved in hydrogen bonds.…”

Synthesis, structure, proton-nuclear magnetic resonance, and Fourier transform infrared spectroscopy of several transition and nontransition metal–adenosine-5-triphosphate complexes

“…The spectra were taken using KC1 pellets and the resolution was 2-4 cm-'. Previous procedures of data collecting and I calculating the spectra were used (13). The compounds were analyzed I and the metal ions were determined complexometrically.…”

Synthesis of gamma radiation-induced PEGylated cisplatin for cancer treatment

“…The group of bands at 1646 cm À1 , 1539 cm À1 , 1310 cm À1 is assigned to the amine in-plane bend (d(N-H)), while the band at 813 cm À1 is ascribed to the amine out-of-plane bend (d p (N-H)). 29 Four other strong bands at 523 cm À1 , 317 cm À1 , 248 cm À1 and 157 cm À1 , are attributed to symmetric n s (Pt-N), asymmetric stretching vibration n a (Pt-Cl), N-Pt-N, and Cl-Pt-Cl bending vibrations respectively. 30 Aqueous cisplatin (1 mg mL À1 ) was also surveyed by FT-Raman ( Fig.…”