The reactions of 2-hydroxypyridine ligands with Re 2Cl 4(μ-dppm) 2 (dppm=Ph 2PCH 2PPh 2) that lead to 2-pyridonate complexes

Abstract

2-Hydroxypyridine (Hhp), 2-hydroxynicotinic acid (HnicOH) and 6-hydroxypicolinic acid (HpicOH) react with Re 2Cl 4(μ-dppm) 2 (dppm=Ph 2PCH 2PPh 2) to afford the complexes Re 2(η 2-hp)Cl 3(μ-dppm) 2 ( 1), Re 2(η 2-HnicO)Cl 3(μ-dppm) 2 ( 2) and Re 2(μ-picO) 2(μ-dppm) 2 ( 3). The identities of 1 and 2 have been established by single-crystal X-ray structure determinations (Re–Re distances of 2.2602(3) and 2.2539(3) Å, respectively) and they are shown to have unsymmetrical structures with staggered rotational geometries and trans, cis coordination of the pair of μ-dppm ligands. The crystal of 2 that was used in the structure determination was found to be of composition 2Re 2(η 2-HnicO)Cl 3(μ-dppm) 2 · Re 2Cl 6(μ-dppm) 2 · 2.906CH 2Cl 2. The structure of Re 2Cl 6(μ-dppm) 2 in this crystal is compared with structures reported in the literature for other crystals that contain this edge-sharing bioctahedral dirhenium(III) complex.