N-[2-(4-methoxyphenyltelluro)ethyl]phthalimide (L1): synthesis, oxidation by ruthenium(III) chloride and ligation with ruthenium(II). Crystal structures of L1, its oxidized product and of [RuCl2(p-cymene)·L1]

N-[2-(4-methoxyphenyltelluro)ethyl]phthalimide (L1) synthesized by reacting ArTe− (generated in situ) with N-(2-bromoethyl)phthalimide, has been characterized structurally. The TeC(alkyl) (2.147(5) Å) is somewhat longer than TeC(aryl) (2.111(4) Å). The L1 on reaction with RuCl3·xH2O results in a novel heterocycle, Techloro,Teanisyl-1a-aza-4-oxa-3-tellura-1H,2H,4aH-9-fluorenone (1), which is characterized structurally and is a unique example of a tellura heterocycle containing oxygen as well as nitrogen in the same ring. The oxidation state of Te changes to +IV in the formation of 1. The TeCl and TeO bond lengths in 1 are 2.604(2) and 2.038(4) Å, respectively. The reaction of L1 with [RuCl2(p-cymene)]2 gives [RuCl2(p-cymene)·L1] (2) which is characterized structurally. The RuC (av), RuCl and RuTe bond lengths are 2.192(1), 2.417(1)–2.434(1) and 2.651(5) Å, respectively. The difference in TeC(alkyl) and TeC(aryl) bond lengths is not affected on the ligation of L1 with ruthenium(II).