Phosphine analogs of cisplatin. Synthesis and x-ray structure of bis(.mu.-hydroxo)bis(bis(trimethylphosphine) platinum(II) dinitrate and its reactivity with 1-methylcytosine. X-ray structure of bis(.mu.-1-methylcytosinato-N3,N4)bis(bis(trimethylphosphine)platinum(II) dinitrate

Abstract

The complex cis-[ (PMe3)2Pt(p-OH)]2(N03)z has been prepared and characterized by multinuclear 'H, 31P, and i95Pt NMR spectroscopy. The dimeric nature of the cationic complex found in solution has been confirmed in the solid state by single-crystal X-ray analysis. The compound crystallizes in the monoclinic system, space group P 2 i / n , with a = 15.51 1 (7) A, b = 12.315 (5) A, c = 6.964 (4) A, p = 97.67 ( 4 ) ' . and Z = 2. The structure was solved by heavy-atom methods and refined by least-squares techniques to R = 0.048 for 2748 unique data ( I L 340). The cationic unit ~is-[(PMe,)~Pt(p-oH)]?' contains bridging hydroxo ligands with the Pt atoms in a distorted square-planar geometry. The P-Pt-P and 0-Pt-0 angles are 95.4 (1) and 75.9 (4)O, respectively. The P4Pt202 skeleton is planar with a rather short 0---0 distance (2.54 ( I ) A). The reaction of this complex with I-methylcytosine (I-MeCy) has been investigated, in H 2 0 and dimethyl sulfoxide (DMSO), by "P NMR spectroscopy. cis-[(PMe3)2Pt(pOH)]p reacts with the nucleobase, at room temperature in a few hours, with deprotonation of the exocyclic amino group and metal coordination of the cytosinate ligand. The main reaction product is the dinuclear complex cis-[(PMe,),Pt(p-I -MeCy(-H))],(NO,),, which has been characterized in solution by multinuclear NMR spectroscopy and in the solid state by single-crystal X-ray analysis. The complex crystallizes in the triclinic system, space group Pi, with a = 10.320 (4) A, b = 10.431 (5) A, c = 17.426 (8) A, CY = 92.39 (4)O, ( 3 = 99.13 (4)O, y = 94.54 (5)O, and Z = 2. The structure was solved by heavy-atommethods and refined to R = 0.038 for 5900 unique data ( I L 341)). The two deprotonated I-MeCy molecules bridge two cis-(PMe3),Pt moieties in a N3,N4 head-to-tail fashion to form a dinuclear species in which the coordination planes of the two metal atoms form a dihedral angle of 46.2'. At 80 'C, in H20 or DMSO solution, the complex dissociates to the corresponding mononuclear species. The molecular structures and the solution state of the prepared complexes are discussed with reference to those of the amine analogues.

Unusual Dimeric Zn(II)-cytosine complexes: New models of the interaction of Zn(II) with DNA and RNA

“…A particular situation is found in the dimer [ZnCl(9-Pr-en-GH-N7) 2 ] 2+ in which the functionalization of the N9 position of the nucleobase by a diamine group allows the Zn atom coordinate guanine via N7 and diamine sites [34]. It is also unusual the situation involv- [35][36][37][38][39][40][41][42][43][44], Pd(II) [45,46] probably due to an initial N3 ! N4 migration of the transition metal [38,47,48]; other cases are (1-MeC-N3)-Cu(II)-(1-MeC-N4) 2 [49], (1-MeC-N3)-Ag(I)-(1-MeC-O2) [13], (1-MeC-N4) 2 -Cu(II)-(1-MeC-O2) 2 [50], and (1-MeC À -N4)-Pd(II)-(1-MeC-O2) [51].…”

Hydroxo and Oxo Complexes of Platinum(II) Stabilized by Phosphanes: Synthesis and Characterization − X‐ray Structures of cis‐[L2Pt(μ‐OH)]2(NO3)2 (L = PMe2Ph, PMePh2) and [{cis‐(PMe2Ph)2Pt}3(μ‐O)2]Cl2

“…Unlike the isostructural hydroxo compounds containing the chelate ligands 2,2Ј-bipyridine or phenanthroline, which are inert towards LiCl even at 100°C, [13] [14] cis-[(PMe 3 ) 2 Pt(µ-OH)] 2 X 2 (X ϭ NO 3 , [5] ClO 4 ), [15] and cis-[(PMe 2 Ph) 2 Pt(µ-OH)] 2 (NO 3 ,) 2 [6] were synthesized as previously reported. X-ray Data Collection, Structure Solution and Refinement of 1a, 2, and 4: [16] The X-ray data collections were performed at room temperature with a NicoletϪSiemens four-circle R3m/V diffractometer on single-crystals mounted in thin-walled glass capillaries with graphite-monochromated Mo-K α radiation (λ ϭ 0.71073 Å ).…”

“…In the 1 H NMR spectra, the OH resonances are observed as broad singlets at δ ϭ 4.11 (L ϭ PMe 2 Ph) and 3.53 (L ϭ PMePh 2 ), values similar to that observed for the PMe 3 analogue (δ ϭ 3.46). [5] The 31 P NMR spectra, obtained at 36. [3] the main resonance does not show resolved satellites, which are assigned to the 3 J P,Pt coupling, indicating that the magnetic interaction between the 31 P and 195 Pt nuclei through three bonds is presumably too small to be observed.…”

Synthesis, characterization and cytotoxic properties of platinum(II) complexes containing the nucleosides adenosine and cytidine

“…Adenosine, cytidine and all the solvents (MeOH, Et 2 O, PhCN, CH 3 [20], cis-[(PMe 3 ) 2 Pt(μ-OH)] 2 (NO 3 ) 2 [22], cis-[(PPh 3 ) 2 PtHN=C(Me){1-MeCy(−2H)}]NO 3 (7a) [20], cis-[(PPh 3 ) 2 PtHN=C(Ph){1-MeCy(−2H)}]NO 3 (7b) [21], cis-[(PPh 3 ) 2 PtHN=C(Me) {9-MeAd(−2H)}]NO 3 (8a) [20], cis-[(PPh 3 ) 2 PtHN=C(Me){9-MeAd (−2H)}]NO 3 (8b) [21] were synthesized as previously reported.…”