Synthesis and characterization of mono and polymeric cyclopalladated compounds: Crystal and molecular structure of [{Pd(dmba)(ONO2)}2(μ-pz)] · H2O (pz = pyrazine)

In the treatment of cyclometallated dimer [Pd(dmba)(μ-Cl)]2 (dmba = N,N-dimethylbenzylamine) with AgNO3 and acetonitrile the result was the monomeric cationic precursor [Pd(dmba)(NCMe)2](NO3) (NCMe = acetonitrile) (1). Compound 1 reacted with m-nitroaniline (m-NAN) and pirazine (pz), originating [Pd(dmba)(ONO2)(m-NAN)] (2) and [{Pd(dmba)(ONO2)}2(μ-pz)] · H2O (3), respectively. These compounds were characterized by elemental analysis, IR and NMR spectroscopy. The IR spectra of (2–3) display typical bands of monodentade O-bonded nitrate groups, whereas the NMR data of 3 are consistent with the presence of bridging pyrazine ligands. The structure of compound 3 was determined by X-ray diffraction analysis. This packing consists of a supramolecular chain formed by hydrogen bonding between the water molecule and nitrato ligands of two consecutive [Pd2(dmba)2(ONO2)2(μ-pz)] units.

Graphical abstractThe compound [Pd(dmba)(NCMe)2](NO3) (NCMe = acetonitrile) (1) reacts with m-nitroaniline (m-NAN) and pirazine (pz), affording [Pd(dmba)(ONO2)(m-NAN)] (2), [{Pd(dmba)(ONO2)}2(μ-pz)] · H2O (3), respectively. The IR spectra of (2–3) display typical bands of monodentade O-bonded nitrate groups. The crystal structure of compound 3 consists of a supramolecular chain formed by hydrogen bonding between the water molecule and the nitrato ligands of two consecutive [Pd2(dmba)2(ONO2)2(μ-pz)] units.Figure optionsDownload full-size imageDownload as PowerPoint slide