title: Cubane-like tetranuclear Cu(ii) complexes bearing a Cu4O4core: crystal structure, magnetic properties, DFT calculations and phenoxazinone synthase like activity.
abstract: In the present work, two new copper complexes 3a and 3b with a Cu4O4cubane core are reported. Both complexes are obtained by means of the in situ conversion of the imine functionality of Schiff's base ligands 1a [(E)-4-chloro-2-((thiazol-2-ylimino)methyl)phenol] and 1b [(E)-4-bromo-2-((thiazol-2-ylimino)methyl)phenol] into amino alcohols 2a (4-chloro-2-(hydroxy(thiazol-2-ylamino)methyl)phenol) and 2b (4-bromo-2-(hydroxy(thiazol-2-ylamino)methyl)phenol), respectively. The ligand transformation may be metal assisted and the generated ligands show an interesting mode of coordination in which the alkoxo-O atom binds in a μ3-manner connecting simultaneously three copper centers and forming a Cu4O4cubane core. The first analysis of single crystal X-ray diffraction studies reveals that both molecules possess a [4 + 2] cubane-type core, and low temperature magnetic measurements show antiferromagnetic behaviour, in agreement with DFT calculations. However, the best fit and DFT calculations point out three pairs of coupling constants, more coherent with a [2 + 2 + 2] situation, in accordance with the fine analysis of structural data. Finally, phenoxazinone synthase activity has been measured for both molecules, finding kcat= 86.3 h-1for the chloride derivative copper(ii) complex in methanol, whereas the bromide derivative copper(ii) complex displays kcat= 3.4026 × 102h-1and 10.289 × 102h-1in methanol and DMSO, respectively.
authors.affiliation: Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi-835215, Jharkhand, India.
authors.forename: Shipra
authors.initials: S
authors.lastname: Sagar
authors.affiliation: Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi-835215, Jharkhand, India and Department of Chemistry, Indian Institute of Engineering Science and Technology-Shibpur, Howrah-711103, India.
authors.forename: Swaraj
authors.initials: S
authors.lastname: Sengupta
authors.affiliation: Department of Inorganic Chemistry, Faculty of Sciences, University of Granada, Avda. Fuentenueva, s/n, 18002 Granada, Spain.
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Mota
authors.affiliation: Department of Chemistry, Indian Institute of Engineering Science and Technology-Shibpur, Howrah-711103, India.
authors.forename: Shyamal K
authors.identifier: http://orcid.org/0000-0002-9726-922X
authors.initials: SK
authors.lastname: Chattopadhyay
authors.affiliation: Department of Organic Chemistry, University of Murcia, Campus de Espinardo, 30100 Murcia, Spain. artuesp@um.es.
authors.forename: Arturo
authors.initials: A
authors.lastname: Espinosa Ferao
authors.affiliation: Equipe Chimie Inorganique, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris Sud, Bâtiment 420 - Rue du Doyen Georges Poitou, 91400 Orsay, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Riviere
authors.affiliation: School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: William
authors.identifier: http://orcid.org/0000-0001-7103-6981
authors.initials: W
authors.lastname: Lewis
authors.affiliation: Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi-835215, Jharkhand, India.
authors.forename: Subhendu
authors.identifier: http://orcid.org/0000-0002-9824-2555
authors.initials: S
authors.lastname: Naskar
mesh_terms: D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004563:Electrochemistry; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010088:Oxidoreductases / Q000378:metabolism*; D011789:Quantum Theory
chemical_list: D009942:Organometallic Compounds; D003300:Copper; D010088:Oxidoreductases; C023944:2-aminophenol oxidase