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Lorenzo D’Amore, Leonardo Belpassi, Johannes E. M. N. Klein, Marcel Swart
Spin-resolved charge displacement analysis as an intuitive tool for the evaluation of cPCET and HAT scenarios
Chem. Commun. , 2020, 56, 12146-12149
Saikat Banerjee, Apparao Draksharapu, Patrick Crossland, Ruixi Fan, Yisong Guo, Marcel Swart, Lawrence Que
Sc3+-promoted O–O bond cleavage of a (?-1,2-peroxo)diiron(III) species formed from an iron(II) precursor and O2 to generate a complex with an FeIV2(µ-O)2 core
J. Am. Chem. Soc., 2020, 142, 4285-4297
K. Rajabimoghadam, Y. Darwish, U. Bashir, D. Pitman, S. Eichelberger, M. Siegler, M. Swart and I. Garcia-Bosch
Catalytic Aerobic Oxidation of Alcohols by Copper Complexes Bearing Redox-Active Ligands with Tunable H-bonding Groups
J. Am. Chem. Soc. 2018, 140, 16625-16634
M. Swart and M. Gruden
Spinning around in transition-metal chemistry
Acc. Chem. Res. 2016, 49, 2690-2697
It has long been recognized that metal spin states play a central role in the reactivity of important biomolecules and in inorganic chemistry catalysis. Molecules with different numbers of unpaired electrons, hence with different spin states, have distinct geometric structures, energetic properties and reactivity. Elucidating the role and effect of different spin states on the properties of a system is presently one of the most challenging endeavors both from an experimental and theoretical point-of-view. This is in particular true for reaction mechanisms where the spin-state and/or oxidation state of a metal can change during the reaction. It has been described extensively in the recent Wiley book on “Spin states in Biochemistry and inorganic chemistry: Influence on Structure and Reactivity” (Eds: M. Swart, M. Costas).
The reaction mechanism of chemical processes with transition-metals can (and often does) involve a switching from one spin-state to another during the reaction. This allows to overcome the low activity of molecules like dioxygen (in its triplet state), and facilitates reactions that would otherwise be spin-forbidden. Moreover, given the wide range of mechanistic possibilities available with the presence of transition-metals, often a multitude of reaction mechanisms has to be considered. In collaboration with experimental groups we are carrying out computational chemistry experiments to characterize intermediates and transition structures, to determine the most favorable reaction path.
In 2010 a ground-breaking experimental study by Fukuzumi and Nam was published in Nature Chemistry where they showed that adding Sc(OTf)3 to a FeIV-oxo complex (with the TMC ligand) has unprecedented consequences: (i) the axial ligand of iron is removed; (ii) scandium picks up a fourth triflate and an additional fifth axial ligand; (iii) the methyl groups of the TMC-ligand flip upwards (from anti towards oxo, to syn); and (iv) this interaction facilitates a two-electron reduction by ferrocene, instead of the one-electron reduction without the Lewis acid. This has opened a whole new research area where reactive species can be stabilized, or reactivity can be drastically improved. The effect of the Lewis acids on the stability, reactivity and spectroscopic properties is poorly understood, and is being studied here in collaboration with experimental groups.
In order to be able to carry out the spinning around in transition-metal chemistry, new research tools have been developed such as the QUILD program with improved optimization and transition-search routines, and new density functionals (S12g, SSB-D) that work well for both spin states and weak interactions. The advantage of these tools is that they can be applied straightforwardly also to other systems such as DNA, SN2-reactions, NMR chemical shifts and the like
PhD Student (FPI)Supervisor:
Since 2015 the IQCC is organizing a Science Slam. Next week on Thursday
Cyano lambda3-iodanes react with iron(II) and iron(III) complexes as cyano-transfer one-electron oxidants. This
Next Friday (10th of December, 11.00h, Sala de Graus – Facultat de Dret)
Last October 28th, close to 700 students from 22 different high schools all around