Selenoether macrocyclic chemistry-syntheses and ligand properties of new small-ring Se(3)- and Se(2)N-donor macrocycles.
Simultaneous dropwise addition of thf/EtOH solutions of Se{(CH(2))(3)OTs}(2) and o-C(6)H(4)(CH(2)SeCN)(2) or NCSe(CH(2))(3)SeCN to a suspension of NaBH(4) in thf/EtOH at room temperature yields gram quantities of the 13- and 12-membered triselenoether macrocycles (1) and (2) respectively in high yield. The 11-membered ring (3) is obtained similarly by simultaneous dropwise addition of thf/EtOH solutions of Na(2)[o-C(6)H(4)Se(2)] (itself prepared by NaBH(4) reduction of the polymeric [o-C(6)H(4)Se(2)](n)) and Se{(CH(2))(3)OTs}(2) to a suspension of NaBH(4) in thf/EtOH. The small-ring, potentially tridentate Se(2)N(pyridyl)-donor macrocycles (4) and (5) were obtained in essentially quantitative yield by simultaneous dropwise addition of thf/EtOH solutions of 2,6-bis(bromomethyl)pyridine and either o-C(6)H(4)(CH(2)SeCN)(2) or NCSe(CH(2))(3)SeCN to a suspension of NaBH(4) in thf/EtOH at room temperature. (1)-(5) have been characterised by (1)H, (13)C{(1)H} and (77)Se{(1)H} NMR spectroscopy, EI MS, and for (1) and (4), by X-ray crystal structures. Reaction of PtMe(3)I with one mol. equiv. of L (L = (1)-(5)) in refluxing CHCl(3) gives the ionic complexes [PtMe(3)(L)]I cleanly and in good yield. These were characterised by (1)H, (13)C{(1)H}, (77)Se{(1)H} and (195)Pt NMR spectroscopy, electrospray MS, microanalyses and by crystal structures of [PtMe(3)((1))]I and [PtMe(3)((4))]I, which confirm distorted octahedral coordination at Pt(IV), with fac-tridentate coordination of the macrocycle in all cases, with anionic iodide. The complexes [PtCl(2)(L)] (L = (1)-(3)) were obtained as poorly soluble yellow-orange solids by reaction of PtCl(2) with L in MeCN solution. The d(3) Cr(III) complexes of L (L = (1)-(5)) were obtained by reaction with [CrCl(3)(thf)(3)] in anhydrous CH(2)Cl(2) as distorted octahedral fac-[CrCl(3)(L)], as poorly soluble blue-purple through to green powdered solids, which have been characterised by microanalysis, UV-visible and IR spectroscopy and by their magnetic moments. The properties of these complexes are compared with related chalcogenoether complexes from the literature involving thioether and acyclic selenoether coordination.
Levason
William
W
School of Chemistry, University of Southampton, Southampton, UKSO17 1BJ.
Manning
Joanna M
JM
Reid
Gillian
G
Tuggey
Matthew
M
Webster
Michael
M