A family of [Cu2], [Cu4] and [Cu5] aggregates: alteration of reaction conditions, ancillary bridges and capping anions. (3rd August 2018)

• Record Type: Journal Article
• Authors: Das, Manisha; Craig, Gavin A.; Escudero, Daniel; Murrie, Mark; Frontera, Antonio; Ray, Debashis
• Is Part Of: New journal of chemistry. Volume 42:Number 17(2018)
• Page Start: 14349
• Page End: 14364
• Publication Date: 2018-08-03
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj02131g
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Enforced coordination by NO3 −, ClO4 − and CF3 COO − groups resulted in the formation of [Cu2 ] (1 ), [Cu4 ] (2 ) and [Cu5 ] (3 ) complexes using H5 L1. Abstract : The phenoxido-bridged [Cu2 ] complex [Cu2 (μ-H4 L1)(μ-OH)(μ1, 3 -NO3 )(NO3 )(OH2 )]·H2 O (1 ) and its hierarchical [Cu4 ] and [Cu5 ] assemblies [Cu4 (μ-H4 L1)2 (μ-OH)2 (μ1, 3 -ClO4 )(OH2 )2 ](ClO4 )3 ·2H2 O (2 ) and [Cu5 (μ-H4 L1)2 (μ3 -OH)2 (μ1, 3 -O2 CCF3 )2 (O2 CCF3 )2 ](CF3 COO)2 (3 ) were obtained from the reactions of H5 L1 (2, 6-bis-{(1, 3-dihydroxy-2-methylpropan-2-ylimino)methyl}-4-methylphenol) with three copper(ii ) salts. The available NO3 −, ClO4 − and CF3 COO − ions have been trapped for 'spontaneous' anion-directed 'self-assembly' reactions. All the synthesized complexes contain the [Cu2 (μ-H4 L1)(μ-OH)] 2+ fragment, prone to assemble and crystallize [Cu4 ] and [Cu5 ] complexes under varying reaction conditions. They were characterized by UV-vis and IR spectroscopy, X-ray diffraction analysis and magnetic studies. A change from NO3 − to ClO4 − and CF3 COO − results in different courses of reactions based on Cu2 (μ-H4 L1) fragments. Binding of NO3 − provided1 as an isolated [Cu2 ] complex by trapping the reactive fragment. In2 a perchlorate ligand, in the μ1, 3 -binding mode, has been realized as a solitary support for the condensation of two Cu2 (μ-H4 L1) fragments. The {Cu5 (μ3 -OH)2 (μ1, 3 -O2 CCF3 )2 } 6+ constellation in3 contains five Cu II centers with a unique Z-in distorted octahedral one at the central position. Binding of different anions to the copper(ii ) centers controls the nuclearity of the reaction products and tuning of the self-aggregation process within the same ligand environment (μ-H4 L1 − ). The magnetic properties of the compounds have been studied both experimentally and using DFT calculations, revealing moderate to strong antiferromagnetic coupling in all aggregates.