Design, synthesis and reactivity with dichloro-bis(triphenylphosphine) platinum(II) of two triazenide compounds

In the presence of sodium nitrite, the reaction of methyl anthranilate and 2-aminopyridine or o-aminobenzoic acid gives two triazenes, 1-[(2-carboxymethyl)benzene]-3-[2-pyridine]triazene (HL) and 1-[(2-carboxymethyl)benzene]-3-[o-aminobenzoic acid]triazene (H2L′), respectively. In the presence of Et3N, the reaction of Pt(PPh3)2Cl2 and HL or H2L′ produces two triazenido platinum(II) complexes, Pt(PPh3)2(L)Cl (1) and Pt(PPh3)2(L′) (2), respectively, which have been characterized by X-ray crystallography, 31P NMR spectra, UV–Vis spectra, emission spectra and cyclic voltammetry. When excited at 310 nm, complexes 1 and 2 show luminescence at 432 and 442 nm, respectively, which is consistent with the trend of the lowest-energy absorption wavelengths of 1 (376 nm) and 2 (379 nm). Complexes 1 and 2 exhibit one or two redox waves and follow the order 1 (0.97 V) → 2 (0.89 and 0.07 V), which is also in accordance with the trend of the lowest-energy absorption spectra of 1 (376 nm) and 2 (379 nm).