Trichloro(9-methylguaninium)platinum(II) hydrate and 9-methylguaninium hexachloroplatinate(IV) dihydrate: synthesis and structure

Abstract

The complex trichloro(9-methylguaninium)platinum(II) hydrate, (9-MeGuaH)PtC13.H20, and the salt 9-methylguaninium hexachloroplatinate(1V) dihydrate, (9-MeG~aH)~PtCb.2H~0, have been synthesized and their structures determined. The complex crystallizes in the orthorhombic space group P c 0 2~ with a = 15.327 (3) A, b = 8.672 (2) A, c = 9.496 (2) A, V = 1262.2 A3, 2 = 4, Dmd = 2.53 g cnr3, and D = 2.555 g 6x11~~. The salt crystallizes in the space group Pi with a = 10.425 (4) A, b = 8.732 (3) A, c = 6.638 (2) x a = 98.74 (4)O, j3 = 96.72 (3)O, y = 97.00 (4)O, V = 587.1 R3, z = 1, Dmd = 2.19 g and Ddd = 2.195 g ~m -~. Both structures were solved by heavy-atom methods and were refinedto an R index of 0.048 for the complex and 0.027 for the salt. In the complex the square-planar Pt(I1) is bound to N7 of the guanine ligand, which is protonated at N3. There is no Pt-06 interaction. In the salt, guanine is protonated at N7.

Exploration of Charge-Transfer Solids Utilizing Nucleobases: Nanoarchitectures by Hydrogen-Bonds in the Ionic Assemblies of Guanine and TCNQ Derivatives

“…In salt 3 , BuGH + molecules form a dimer with the Type 2 H-bond pairing, and the dimers are connected by MeOH-mediated H-bonds (Figure a). Similar solvent-mediated 1D ribbon structures have been observed in the hydrate salts of protonated 9-methylguanine ( MeGH + ) and EtGH + . The N1 sites of BuGH + molecules of 3 fixed the anion molecules by H-bonds (N1–H···N16C), in which MeOH participation is the key feature responsible for adjusting the separation between the N1 sites of the neighboring BuGH + dimers (see the two red lines in Figure b) to the separation observed between the N16 sites of the F 2 TCNQ •– dimers (9.6 Å).…”

Structure of bis[pentaamminechloroiridium(III)] hexachloroplatinate(IV) dichloride

“…The Pt--CI bond lengths in related structures containing the PtC162-anion are in the range 2.310 (4)-2.314 (1) A (Bisi-Castellani, Manotti-Lanfredi, Tiripicchio, Maresca & Natile, 1984;Ohba & Saito, 1984;Terzis & Mentzafos, 1983;Delafontaine, Toffoli, Khodadad & Rodier, 1987) which compare favourably with our average value of 2.319 (12)/~, since PtCI6 is subject to only 2/m symmetry. The Ir atom exhibits a more distorted octahedral surrounding than that in Ir(NH3)sC1.C12 (Hambley & Lay, 1986).…”

Platinum(II) binding to N7 and N1 of guanine and a model for a purine-N1,pyrimidine-N3 cross-link of cisplatin in the interior of a DNA duplex

“…22 Thus, Ag+ appears to behave like H+, which has been demonstrated by X-ray analysis to bind to N7-platinated, neutral guanine through N3. 42,43 As far as guanine modes of 4 in the double-bond stretching region of the IR spectra are concerned, they are qualitatively more similar to those of 2 rather than those of 1. Compound 5 is not considered because of a higher complexity due to the presence of 1-MeU resonances.…”