title: Synthetic Ways to Tris(nucleobase) Complexes Derived from cis-Diammineplatinum(II) and a Platinum(II) Complex Containing Four Different Ligands, Three of Which Are Nucleobases.
abstract: Reactions of cis-[PtCl(L-N7)(NH(3))(2)]Cl (L = 9-ethylguanine, 9-EtGH, or 9-methyladenine, 9-MeA) with excess KI leads in slightly acidic solution to trans-PtI(2)(L)(NH(3)). Partial or complete substitution of the iodo ligands by aqua, chloro, or nucleobase ligands can be achieved and gives a series of neutral or cationic complexes. Among others, tris(nucleobase) complexes containing three different nucleobases (9-EtGH, 9-MeA, and 1-methylcytosine, 1-MeC), [Pt(1-MeC)(9-EtGH)(9-MeA)(NH(3))](2+) with SP-4-3 and SP-4-4 configuration numbers have been prepared and the deprotonated form SP-4-4-[Pt(1-MeC-N3)(9-EtG-N7)(9-MeA-N7)(NH(3))]NO(3).2H(2)O (7b) has been X-ray structurally characterized: monoclinic system, space group C2/c, a = 23.817(5) Å, b = 10.992(2) Å, c = 21.647(4) Å, beta = 112.07(3) degrees, V = 5251.9 Å(3), Z = 8. Moreover, the X-ray crystal structure analyses of trans-PtCl(2)(9-EtGH-N7)(NH(3)).0.5H(2)O (4) and trans-[Pt(1-MeC-N3)(2)(9-EtG-N7)(NH(3))]NO(3).3H(2)O (6b) are reported. 4: triclinic system, space group P&onemacr; (No. 2), a = 11.557(3) Å, b = 12.742(2) Å, c = 8.880(2) Å, alpha = 96.95(1) degrees, beta = 94.91(2) degrees, gamma = 88.32(2) degrees, V = 1293.1(5) Å(3), Z = 4. 6b: triclinic system, space group P&onemacr; (No. 2), a = 10.957(2) Å, b = 11.022(2) Å, c = 12.916(2) Å, alpha = 81.18(3) degrees, beta = 89.93(3) degrees, gamma = 64.22(3) degrees, V = 1384.2(5) Å(3), Z = 2. Relative orientations of the nucleobases in these compounds appear to be dictated by intranucleobase H bond formation.
authors.affiliation: Fachbereich Chemie, Universität Dortmund, D-44221 Dortmund, Germany, and Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hegmans
authors.forename: Michal
authors.initials: M
authors.lastname: Sabat
authors.forename: Ivan
authors.initials: I
authors.lastname: Baxter
authors.forename: Eva
authors.initials: E
authors.lastname: Freisinger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lippert