98218-99-6Relevant articles and documents
Ruthenium(II)-6-mercaptopurine complex synthesis and solution properties. Molecular and crystal structure of bis(6-mercaptopurine)bis(triphenylphosphine)ruthenium(II) chloride
Cini, Renzo,Cinquantini, Arnaldo,Sabat, Michael,Marzilli, Luigi G.
, p. 3903 - 3908 (2008/10/08)
The preparations of the complexes [RuII(6-MP)2(P(C6H5) 3)2]Cl2·2C2H 5OH·2H2O (1) (6-MP = 6-mercaptopurine), [RuII(6-MP-9-Me)2(P(C6H5) 3)2]Cl2·1.5H2O (2) (6-MP-9-Me = 6-mercapto-9-methylpurine), [RuII(6-MP)(6-MP-H)(P(C6H5)3) 2]Cl (3) (6-MP-H = N(9)-deprotonated 6-mercaptopurine), and [RuII(6-MP-1-Me-9-Me)2(P(C6H5) 3)2]Cl2·H2O (4) (6-MP-1-Me-9-Me = 1,9-dimethyl-6-mercaptopurine), together with the molecular and crystal structure of 1, are reported. Complexes 1 and 2 were prepared from ethanol solution under nitrogen by treating [RuIICl2(P(C6H5)3) 3] with the stoichiometric amount of the mercapto ligand. Compound 1 crystallizes in the monoclinic system, space group P21/a with a = 29.504 (4) A?, b = 16.848 (3) A?, c = 10.542 (2) A?, β = 97.78 (3)°, V = 5192 A?3 (at 22 °C), Z = 4, Dcalcd = 1.45 g cm-3, and μ(Mo Kα) = 5.47 cm-1. Intensities for 2991 reflections were collected by using the θ-2θ scan technique employing graphite-monochromatized Mo Kα radiation. The structure was solved by the Patterson method. Full-matrix least-squares refinement has led to final R and Rw, values of 0.056 and 0.054, respectively. The structure contains [RuII(6-MP)2(P(C6H5) 3)2]2+ cations, chloride anions, and free water and ethanol molecules. The coordination sphere about the ruthenium(II) center is approximately octahedral. The two 6-MP molecules act as bidentate ligands via the S(6) and N(7) atoms and are protonated at N(1) and N(9). The two sulfur atoms are in trans positions. The Ru-S distances are 2.417 (4) and 2.447 (4) A?, respectively, and the Ru-N bond lengths average 2.156 (14) A?. The double-bond character of the C-S group is not significantly altered by coordination, and the purine system is essentially planar. The bite distance S-N(7) (average value 3.10 A? in the complex) is significantly shorter than in the free ligand (3.352 A?). Strong intermolecular and intramolecular stacking interactions occur between purine systems and between purine and phenyl rings. Water, ethanol molecules, chloride ions, and H-N(1) and H-N(9) are involved in a network of hydrogen bonds. The title complex in Me2SO-d6 was studied by 1H and 31P NMR spectroscopy. The H(2) and H(8) signals of 1 and 3 were assigned by selective deuteration. The 1H NMR spectrum was monitored as a function of added base and/or added CH3I. On addition of base to solutions of 1, the H(8) signal was most affected, consistent with H-N(9) deprotonation. A complex series of reactions occurs on addition of CH3I under strongly basic conditions, and 2 was not identified as one of the products. However, when mild basic conditions were used, a simpler process was observed on addition of CH3I. When a slight excess of CH3I was added to a mixture containing 1 and NaHCO3, the methylation occurred at N(1) and N(9) and complex 4 was isolated in 50% yield. We speculate that the N(1) proton becomes sufficiently acidic on N(9)-alkylation for additional alkylation to proceed at N(1).
