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A novel coordination mode of κ¹-N-Br-pyridylbenz-(imida, oxa or othia)-zole to Pt(ii): synthesis, characterization, electrochemical and structural analysis

Nicasio-Collazo, Juan, Ramírez-García, Gonzalo, Flores-Álamo, Marcos, Gutiérrez-Granados, Silvia, Peralta-Hernández, Juan M., Maldonado, José Luis, Jimenez-Halla, J. Oscar C., Serrano, Oracio
RSC advances 2019 v.9 no.25 pp. 14033-14039
Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, acetonitrile, crystal structure, dimethyl sulfoxide, electrochemistry, geometry, ligands, melting point, nuclear magnetic resonance spectroscopy, platinum, spectral analysis, ultraviolet-visible spectroscopy
Herein, three novel Pt(ii) complexes with formula [trans-Pt(Br-PyBenz-X)(Cl)₂(DMSO)] (1–3) having Br-pyridylbenz-(imida, oxa or othia)-zole (L₁–₃) derivatives as potential bidentate ligands, under an unusual κ¹-N-coordination mode are reported. All compounds were obtained straightforwardly via reaction of corresponding LPB₁–₃ and [Pt(Cl)₂(DMSO)₂] (DMSO = dimethyl sulfoxide), at 100 °C in acetonitrile, respectively. 1–3 complexes were characterized by analytical and spectroscopic data: melting point, FT-IR, Raman, UV/Vis and NMR experiments. Cyclic voltammetry studies show an irreversible two-electron process at −0.50 and −0.51 V, which was ascribed to the Pt(ii)/Pt(iv) couple, for complexes 2 and 3. The crystal structure of complex 2 was elucidated by single-crystal X-ray diffraction, where the platinum atom exhibits a square plane geometry, where LPB₂ adopts an unusual mono-coordinated mode via an N-κ¹-benzoxazole ring. According to DFT calculations the first N-coordination exchanging one DMSO molecule is favourable, while the second N-coordination is highly impeded.