Iron, cobalt, nickel and ruthenium complexes of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine, a pybox analogue

Article Article scientifique Article Iron, cobalt, nickel and ruthenium complexes of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine, a pybox analogue eng 2003-07 author Cabort Amel author Michel Armelle author Therrien Bruno author Stoeckli-Evans Helen author Bernauer Klaus author Süss-Fink Georg author Williams Alan Francis 25350 author Stupka Gilles 512102 193-200 10.1016/S0020-1693(02)01538-4 0020-1693 https://linkinghub.elsevier.com/retrieve/pii/S0020169302015384 The coordination of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine (L) to nickel, ruthenium, iron, and cobalt was studied. The reaction with nickel salts gives the nickel (II) complex [Ni(L)2]2+ (1). The reaction of ruthenium(III) chloride gives only the ruthenium(II) complex [Ru(L)2]2+ (2). In the case of iron, both [Fe(L)2]2+ (3) and [Fe(L)2]3+ (4) have been synthesised and characterised. In the case of cobalt, the cobalt(III) complex [Co(L)2]3+ (5) is obtained, even if a cobalt(II) salt is used. However, the cobalt(II) [Co(L)2]2+ (6) can be obtained under nitrogen. Molecular structures of 1–5 complexes have been determined by X-ray analysis of the corresponding perchlorate salts; the structure of 3 has been solved for both the perchlorate and the tetrachloroferrate(III) salts. All complexes show an octahedral coordination geometry with meridional arrangement of the two tridentate ligands. The electrochemical behaviour of 2, 3 and 6 has been studied by cyclic voltammetry. Quasi reversible electron transfer is observed for the redox pairs FeIII/FeII and CoII/CoI. The reaction shows somewhat weaker reversibility for CoIII/CoII, whereas the reaction of RuIII/RuII is not reversible. The measurements suggest 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine (L) to have a higher stabilisation of low-valent oxidation states of iron and cobalt than terpyridine. The coordination of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine (L) to nickel, cobalt, ruthenium and iron leads to the formation of the complexes [Ni(L)2]2+ (1), [Ru(L)2]2+ (2), [Fe(L)2]2+ (3) and [Fe(L)2]3+ (4), [Co(L)2]3+ (5) and [Co(L)2]2+ (6). The structures of 1–5, isolated as the perchorate salts, have been solved by single-crystal X-ray structure analysis. The redox properties of 2, 3 and 6 have been studied by cyclic voltammetry. Nickel(II) complexes Cobalt(III) complexes Ruthenium(II) complexes Meridional coordination Octahedral geometry Tridentate ligand Co(I) state stabilisation Crystal structures Iron(II) complexes Iron(III) complexes Dewey 540 40 Département de chimie minérale, analytique et appliquée 145 false Inorganica Chimica Acta 350 80070e1a-a8d6-485f-bd48-b9283d2c9c04 Article (Published version) Restricted 1-s2.0-S0020169302015384-main.pdf 378922 application/pdf Vignette Public 1-s2.0-S0020169302015384-loc1.gif 6695 image/gif restrictedAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

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Iron, cobalt, nickel and ruthenium complexes of 2,6-bis(3,4-dihydro-2H-pyrrol-5-yl)pyridine, a pybox analogue	Inorganica Chimica Acta	2003	118	0

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