Competitive coordination aggregation for V-shaped [Co3] and disc-like [Co7] complexes: synthesis, magnetic properties and catechol oxidase activity. Issue 34 (11th August 2016)

• Record Type: Journal Article
• Authors: Singha Mahapatra, Tufan; Basak, Dipmalya; Chand, Santanu; Lengyel, Jeff; Shatruk, Michael; Bertolasi, Valerio; Ray, Debashis
• Is Part Of: Dalton transactions. Volume 45:Issue 34(2016)
• Page Start: 13576
• Page End: 13589
• Publication Date: 2016-08-11
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt02494g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The synthetic procedures, magnetic properties and catecholase-like activity of a V-shaped [CoII3L4 ] and planar disc-like [CoII7L6 ] complexes have been discussed. Abstract : Unique dependence on the nature of metal salt and reaction conditions for coordination assembly reactions of varying architecture and nuclearity have been identified in V-shaped [Co3 L4 ] and planar disc-like [Co7 L6 ] compounds: [CoII3L2 (μ-L)2 (μ-OH2 )2 (CF3 CO2 )2 ] (1 ) and [CoII7(μ-L)6 (μ-OMe)6 ]Cl2 (2 ) (HL = 2-{(3-ethoxypropylimino)methyl}-6-methoxyphenol). At room temperature varying reaction conditions, cobalt-ligand ratios and use of different bases allowed unique types of coordination self-assembly. The synthetic marvel lies in the nature of aggregation with respect to the two unrelated cores in1 and2 . Complex1 assumes a V-shaped arrangement bound to L −, water and a trifluoroacetate anion, while2 grows around a central Co II ion surrounded by a {CoII6} hexagon bound to methoxide and L − . Magnetic measurements revealed that the intermetallic interactions are antiferromagnetic in nature in the case of complex1 and ferromagnetic in the case of2 involving high spin cobalt(ii ) ions with stabilization of the high-spin ground state in the latter case. In MeCN solutions complexes1 and2 showed catalytic oxidation of 3, 5-di- tert -butylcatechol (3, 5-DTBCH2 ) to 3, 5-di- tert -butylbenzoquinone (3, 5-DTBQ) in air. The kinetic study in MeCN revealed that with respect to the catalytic turnover number ( k cat )2 is more effective than1 for oxidation of 3, 5-DTBCH2 .