Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1336091 | Polyhedron | 2011 | 8 Pages |
The work in this paper reports syntheses, molecular and supramolecular structures, electrochemistry and magnetic properties of two diphenoxo-bridged dinickel(II) compounds [NiII2L(N3)2(H2O)2]·CH3CN (1) and [NiII2L(N3)2(H2O)] (2), where H2L is the tetraimino diphenolate macrocyclic ligand, obtained on [2 + 2] condensation of 4-methyl-2,6-diformylphenol and 2,2′-dimethyl-1,3-diaminopropane. Brown colored compound 1 and green colored compound 2 are produced from the same reaction mixture as a function of temperature; 1 is formed from the reaction mixture in acetonitrile at low temperature (ca. 5 °C), while 2 is formed on heating the reaction mixture in acetonitrile. Crystals of compounds 1 and 2 are monoclinic (space group P21/c) and orthorhombic (space group P212121), respectively. Analyses of the crystal packing of the crystalline phases reveal that two-dimensional topologies are resulted in both 1 and 2 due to hydrogen bonding interactions. Variable-temperature (2–300 K) magnetic susceptibility measurements of the two compounds reveal that the metal centers in both the complexes are coupled by moderate antiferromagnetic interactions with J values (H = –2JS1·S2) −18.8 and −34.2 cm−1 for 1 and 2, respectively. Electrochemical analyses of 2 reveal that this compound exhibits two-step reduction couples at E½ = −977 and −1155 mV.
Graphical abstractSyntheses, molecular and supramolecular structures, electrochemistry and magnetic properties of two diphenoxo-bridged dinickel(II) compounds [NiII2L(N3)2(H2O)2]·CH3CN (1) and [NiII2L(N3)2(H2O)] (2) derived from a tetraimino diphenolate macrocyclic ligand H2L, obtained on [2 + 2] condensation of 4-methyl-2,6-diformylphenol and 2,2′-dimethyl-1,3-diaminopropane, are presented. Compounds 1 and 2 are produced as a function of temperature from the same reaction mixture of the reactants.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Syntheses, structures, and magnetic properties of two diphenoxo-bridged macrocyclic dinickel(II) complexes. ► Formation of two complexes from the same reaction mixture as function of temperature. ► Stabilization of one square pyramidal and one octahedral nickel(II) centers in a symmetrical dinucleating preorganized ligand. ► Weak interaction assisted two-dimensional topologies. ► Antiferromagnetic coupling between metal centers in the title compounds.