N1-coordination in palladium(II) and platinum(II) complexes with 9-methylhypoxanthine: crystal structures and theoretical calculations.
The synthesis of the new palladium and platinum complexes with 9-methylhypoxanthine (9-mhypH) of the type [M(dmba)(L)(9-mhypH-N7)]ClO(4) [dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl; M = Pd or Pt; L = DMSO, PPh(3) or PTA (PTA = 1,3,5-Triaza-7-phosphaadamantane)] is reported. Pd(II) and Pt(II) complexes with the anion of 9-mhypH of the type [M(dmba)(L)(9-mhyp-N1)] [L = PPh(3) or PTA] have also been prepared. The crystal structures of [Pt(dmba)(PPh(3))(9-mhypH-N7)]ClO(4) and [Pt(dmba)(PPh(3))(9-mhyp-N1)] have been established by X-ray diffraction. The last complex is the first structurally authenticated example of N1 coordination of 9-methylhypoxanthine to platinum. DFT-based calculations at the BP86/def2TZVP level predict a most favourable interaction (both kinetically and thermodynamically) of the metal(II) centre with N7 in the neutral ligand 9-mhypH, but with N1 in the deprotonated ligand 9-mhyp(-) in agreement with the experimentally observed preference in neutral conditions or upon basic treatment, respectively.
Ruiz
José
J
Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, 30071, Murcia, Spain. jruiz@um.es
Cutillas
Natalia
N
Villa
María Dolores
MD
López
Gregorio
G
Espinosa
Arturo
A
Bautista
Delia
D
D018360:Crystallography, X-Ray; D016208:Databases, Factual; D007042:Hypoxanthines / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory
C513119:9-methylhypoxanthine; D007042:Hypoxanthines; D009944:Organoplatinum Compounds; D010984:Platinum; D010165:Palladium; D009584:Nitrogen