New Dinuclear Palladium Phosphane Complexes Stabilised by 8‐Thiotheophylline

Abstract

The new purine derivatives SS‐bis‐8‐(thio)‐theophylline (8‐BTTH2) and 8‐phenylthiotheophylline (8‐PhTTH), have been synthesised and characterised by elemental analysis, mass spectrometry and standard spectroscopic measurements. Reaction of 8‐BTTH2 with cis‐[PdCl2(PPh3)2] leads to the formation of the binuclear palladium complex [Pd(PPh3)(μ‐Cl)(8‐TT)]2 (8‐TTH2 = 8‐thiotheophylline) in which PPh3‐induced cleavage of the S−S bridge takes place. This complex reacts with pyridine to give a different dimeric palladium complex, [Pd(μ‐S,N‐8‐TT)(PPh3)Py]2, in which each of the two 8‐thio‐(theophylline) anions binds two metals through the N7 and S atoms. The process leading to the palladium complex has also been elucidated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Biologically Active Platinum Complexes Containing 8-Thiotheophylline and 8-(Methylthio)theophylline

“…The biggest deviation from the coordination plane of 0.032(2) Å corresponds to Cl1 atom [Σ( d /σ) 2 = 459.5 for the coordination plane]. The Pt1−Cl1 and Pt1− N1 distances are 2.337(1) and 2.054(4) Å, respectively, as expected when Cl and N(sp 2 ) are trans to a phosphane group ,− and are in agreement with other similar thiopurine−metal complexes. ,,, The purine molecule is roughly planar [Σ( d /σ) 2 = 101.0] with maximum deviation from the plane for C8 atom of 0.0305 Å while the exocyclic groups do not show any significant deviation from the purine plane. The purine is twisted away from the metal coordination mean plane.…”

“…In the three complexes 1 − 3 , the signals produced by the purine N−CH 3 groups are in the range found for other similar complexes . Nevertheless, it is important to point out that the N3−CH 3 signal moves downfield in the series 1 , 2 , 3 ( 1 , 3.2 ppm; 2 , 3.4 ppm; 3 , 3.6 ppm) showing that the electronic distribution inside the coordinated thiopurine is affected by the nonpurinic ligand.…”

Synthesis of Na2{trans‐[PdCl2(mTPPMS‐κP)2]}: Interaction with DNA and Reactivity with 8‐Thiotheophylline

“…The palladium metal has a distorted square‐planar coordination geometry (P1–Pd1–S8 = 84.99°), with the metal located just on the ligand mean plane. The bond lengths Pd1–P1 [2.339(3) Å] and Pd1–S1 [2.344(3) Å] are longer than those of Pd–P PPh3 [2.266(8) Å] and Pd–S 8TT [2.294(8) Å] found in [Pd(PPh 3 )Py(μ‐S,N‐8‐TT)] 2 , which is the only known example of a 8‐TT monophosphane‐containing Pd complex 9. The bond lengths between N7–C8 [1.369(12) Å] and N7–C5 [1.406(13) Å] support the protonation of N7 8‐TTH shown by NMR and IR spectroscopy, but the proton was not found by difference Fourier synthesis during the X‐ray structural determination.…”

Phosphinic Platinum Complexes with 8-Thiotheophylline Derivatives: Synthesis, Characterization, and Antiproliferative Activity

“…Ligands 8-(methylthio)theophylline (8-MTTH 2 ), bis( S -8-thiotheophylline)methane (MBTTH 2 ), 1,2-bis( S -8-thiotheophylline)ethane (EBTTH 2 ), and 1,3-bis( S -8-thiotheophylline)propane (PBTTH 2 ) have been prepared by following the procedure described by literature methods. , The ligand PTA was prepared as reported as well as Pt complexes cis -[PtCl 2 (PPh 3 ) 2 ] and cis -[PtCl 2 (PTA) 2 ] …”