Synthesis and X-ray structures of triphenylphosphine–mercury(II) thiosalicylate complexes: novel aggregation processes

Abstract

Reaction of [HgCl 2(PPh 3) 2] with one equivalent of thiosalicylic acid (tsalH 2, HSC 6H 4CO 2H) and excess triethylamine, followed by recrystallisation from dichloromethane–diethyl ether gives the compound [Hg 2(tsal) 2(PPh 3) 2] ( 2). This has a bis(S,O)-chelated mercury centre with a nido-trigonal bipyramidal coodination, with the four oxygens of the two carboxylates also coordinated to a Hg(PPh 3) 2 moiety. When a reduced quantity of pyridine was used as the base a different crystalline product was isolated. This was characterised as [Hg 2(tsal) 2(PPh 3) 2][Hg(tsalH) 2] ( 3), which contains the same [Hg 2(tsal) 2(PPh 3) 2] moiety found for 2, co-crystallised with a [Hg(tsalH) 2]. The two mercury–thiosalicylate species are connected by means of O–H⋯O hydrogen bonding.