Selenosalicylate; a little-studied heavy-element analogue of the versatile thiosalicylate ligand.

Selenosalicylic acid (-HSeCHCOH), the heavy element congener of the widely studied thiosalicylic acid, was prepared by reaction of 2-carboxybenzenediazonium chloride (HOCCHNCl) with NaSe, followed by reduction of the resulting diselenide (SeCHCOH) with zinc and acetic acid. The coordination chemistry of the selenosalicylate ligand towards a variety of platinum(ii), palladium(ii), nickel(ii), gold(iii), gold(i), rhodium(iii), iridium(iii) and ruthenium(ii) centres was explored. X-ray crystal structure determinations were carried out on the complexes [Pt(SeCHCO)(PPh)], [{(-cym)Ru(SeCHCO)}] (-cym = η--cymene, CHCHCH(CH)), [{Cp*Rh(SeCHCO)}] (Cp* = η-CMe) and [Cp*Ir(SeCHCO)(PPh)], and comparisons are made with corresponding thiosalicylate complexes. The complexes were characterised by NMR spectroscopy as well as ESI mass spectrometry, which indicated a greater propensity for fragmentation including by selenium loss, compared to the thiosalicylate analogues. Hirshfeld surface analysis to visualise and quantify intermolecular interactions revealed the dominance of H⋯H contacts in [{(-cym)Ru(SeCHCO)}] and [Cp*Ir(SeCHCO)(PPh)].