doi:10.1021/acs.inorgchem.0c01701engSicilia, V.Arnal, L.Fuertes, S.Martín, A.Baya, M.Metal-Metal Cooperation in the Oxidation of a Flapping Platinum Butterfly by Haloforms: Experimental and Theoretical EvidenceART-2020-120327The model 1-DFT for the butterfly complex [{Pt(C¿C*)(µ-pz)}2] (1; HC¿C* = 1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1H-imidazol-2-ylidene) shows two minima in the potential energy surface of the ground state in acetone solution: the butterfly-wing-spreading molecules 1-s, (dPt-Pt ˜ 3.20 Å) and the wing-folding molecules 1-f (dPt-Pt = 3.00 Å). Both minima are very close in energy (¿G° = 1.7 kcal/mol) and are connected through a transition state, which lies only 1.9 kcal/mol above 1-s and 0.2 kcal/mol above 1-f. These very low barriers support a fast interconversion process, resembling a butterfly flapping, and the presence of both conformers in acetone solution. However, the 1-f ratio is so low that it is undetectable in the excitation and emission spectra of 1 in 2-MeTHF of diluted solutions (10-5 M) at 77 K, while it is seen in more concentrated solutions (10-3 M). In acetone solution, 1 undergoes a [2c, 2e] oxidation by CHX3 (X = Cl, Br) in the sunlight to render the Pt2(III, III) compounds [{Pt(C¿C*)(µ-pz)X)}2] (X = Cl (2-Cl), Br (2-Br)). In concentrated solutions, 1 can react with CHCl3 under blue light to give 2-Cl and with CHBr3 in the dark, the latter rendering the compound [BrPt(C¿C*)(µ-pz)2Pt(C¿C*)CHBr2] (3-Br) or mixtures of 2-Br and 3-Br if the reaction is performed under an argon atmosphere or in the air, respectively. Mechanistic studies showed that in concentrated solutions the oxidation processes follow a radical mechanism being the MMLCT-based species 1-f, those which trigger the reaction of 1 with CHBr3 and CHCl3. In the ground state (S0f), it promotes the thermal oxidation of 1 by CHBr3 and in the first singlet excited state (S1f) the blue-light-driven photooxidation of 1 by CHCl3. Complexes, 2-Cl, 2-Br, and 3-Br were selectively obtained and fully characterized, showing Pt-Pt distances (ca. 2.6 Å) shorter than that of the starting complex, 1. They are, together with the analogous [{Pt(C¿C*)(µ-pz)I)}2] and [IPt(C¿C*)(µ-pz)2Pt(C¿C*)CHI2], the only dinuclear metal-metal-bonded PtIII(µ-pz)2PtIII compounds reported to date.2020http://zaguan.unizar.es/record/9569010.1021/acs.inorgchem.0c01701http://zaguan.unizar.es/record/95690oai:zaguan.unizar.es:95690info:eu-repo/grantAgreement/ES/CSIC/2018801070-PIE-147info:eu-repo/grantAgreement/ES/DGA/E17-20Rinfo:eu-repo/grantAgreement/ES/DGA-FEDER/Construyendo Europa desde Aragóninfo:eu-repo/grantAgreement/ES/MICIU-FEDER/PGC2018-094749-B-I00Inorganic Chemistry 59, 17 (2020), 12586-12594All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/openAccess