Co(II), Ni(II) and Cu(II) complexes of new [1+1] and [2+2] macrocyclic ligands derived from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and cis-1,2-diaminocyclohexane

Autor: Laura Valencia Matarranz, Rufina Bastida de la Calle, Alejandro Macías, Ma del Carmen Fernández-Fernández, Paulo Pérez-Lourido
Rok vydání: 2008
Předmět:
Zdroj: Polyhedron. 27:2301-2308
ISSN: 0277-5387
DOI: 10.1016/j.poly.2008.04.043
Popis: Two new macrocyclic ligands, L1 (14-membered N2O2) and L2 (28-membered N4O4) from [1+1] and [2+2] condensation, respectively, have been obtained in a one-pot synthesis starting from 1,4-bis(2′-formylphenyl)-1,4-dioxabutane and cis-1,2-diaminocyclohexane. Both ligands were synthesized in the same pot reaction in satisfactory yield and purity. The use of a washing and recrystallization processes allowed the separation of each macrocyclic ligand. No metal complexes were isolated with the small L1 macrocycle. However, metal complexes with the 28-membered macrocycle L2, using hydrated nitrate and perchlorate salts of transition Co(II), Ni(II) and Cu(II) metal ions, have been synthesized and characterized by microanalysis, LSI mass spectrometry, IR, UV–Vis spectroscopy, magnetic studies and conductivity measurements. Crystal structures of L1, as well as [Co(HL2)(NO3)2(CH3CN)] (NO3) · 2CH3CN, [NiL2(NO3)](NO3) · 2H2O · CH3CN and [Cu2L2(NO3)4] · 4CH3CN complexes, have been determined. The X-ray studies show the presence of a hexacoordinated mononuclear exomacrocyclic complex for Co(II), whilst in the dinuclear Cu(II) complex both copper atoms are exocyclically coordinated by the nitrogen atoms from the ligand in a square planar environment. The crystal structure of [NiL2(NO3)](NO3) · 2H2O · CH3CN shows a mononuclear endomacrocyclic complex with the metal ion in a distorted octahedral environment.
Databáze: OpenAIRE