Mono- and dinucleating Ni(II), Cu(II), Zn(II) and Fe(III) complexes of symmetric and unsymmetric Schiff bases incorporating salicylimine functions - Synthetic and structural studies

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• 作者：Qinghua Meng^a ; ^b ; Jack K. Clegg^a ; ^c ; ; Aidan J. Brock^c ; Katrina A. Jolliffe^a ; ^{k.jolliffe@chem.usyd.edu.au" class="auth_mail} ; Leonard F. Lindoy^a ; ^{lindoy@chem.usyd.edu.au" class="auth_mail} ; Gang Wei^d ; ^{gang.wei@csiro.au" class="auth_mail}
• 关键词：Schiff base ; Nickel(II) ; Copper(II) ; Zinc(II) ; Iron(III)
• 刊名：Polyhedron
• 出版年：28 May, 2014
• 年：2014
• 卷：74
• 期：Complete
• 页码：113-121
• 全文大小：1547 K

文摘

The known Schiff base, 3-(2-aminophenylamino)-1-phenylbut-2-en-1-one (1), formed by 1:1 condensation of o-phenylenediamine and benzoylacetylacetone reacts at its free amine site with salicylaldehyde and 5-tert-butylsalicylaldehyde in the presence of Ni(II) and Cu(II) acetates, or with 5-tert-butylsalicylaldehyde in the presence of Zn(II) acetate, to generate 1:1 (M:L) diimine complexes (2) of the corresponding doubly deprotonated, unsymmetric, O₂N₂-tetradentate ligands. In contrast, reaction of Zn(II) acetate with 1 and salicylaldehyde led to Schiff base exchange (with loss of benzoylacetylacetone) to yield symmetric [ZnL³] [where L³ is N,N鈥?o-phenylenebis(salicyliminato)]. Similarly, when Fe(II) chloride was substituted for metal acetate in the reaction of 1 with 5-tert-butyl-salicylaldehyde and the initial product crystallised in the presence of dabco (as base), a related Schiff base exchange reaction occurred along with aerial oxidation of the Fe(II) to produce the neutral dinuclear [Fe^III(L⁴)₂(渭-O)] species [where L⁴ is N,N鈥?o-phenylenebis(5-tert-butylsalicyliminato)] in which Fe(III) centres are linked by an oxo group to produce two 5-coordinate Fe(III) centres; pairs of these (oxo-bridged) dinuclear complex units are further linked via elongated intermolecular Fe-O_phenolic contacts (Fe-O, 2.44 脜) to form an unusual tetranuclear supramolecular cluster. This complex was also synthesised directly by the in situ reaction of 5-tert-butyl-salicylaldehyde, o-phenylenediamine and Fe(II) chloride (2:1:1 mol ratio) in air. In an extension of these studies, the in situ reaction of the 1,3-aryl linked bis-尾-diketone, 1,1-(1,3-phenylene)-bis-butane-1,3-dione), o-phenylenediamine, salicylaldehyde and Ni(II) acetate in a 1:2:2:2 ratio yielded [Ni₂L⁵], the dinuclear analogue of the unsymmetric mononuclear Ni(II) complex 2, in which each nickel centre has a square planar environment. Reaction of the above 1,3-phenylene linked bis-尾-diketone precursor with o-phenylenediamine in a 1:2 M ratio yields 1,3-bis(4-methyl-3H-benzo[b][1,4]diazepin-2-yl)benzene as its monohydrate (3路H₂O) incorporating two 7-membered diaza heterocyclic rings; thus contrasting with the 鈥榦pen鈥?Schiff base structure observed for 1. X-ray structures of 1, 3路H₂O, [NiL¹]路py, [NiL¹]路EtOH, [NiL²], [CuL¹]路py, [CuL¹]路0.5CHCl₃, [(FeL⁴)₂(渭-O)]₂路1.5THF路0.4EtOH路0.6H₂O and [NiL⁵]路0.25EtOH路0.125py are reported.