Rémi Maurice

Université de Rennes 1 | UR1 · Institut des Sciences Chimiques de Rennes (ISCR) - UMR CNRS 6226

The bond distance is the simplest and most obvious indicator of the nature of a given chemical bond. However, for rare chemistry, it may happen that it is not yet firmly established. In this communication, we will show that the formally-triple protactinium(V) mono-oxo bond is predicted longer than what was previously reported in the solid state and...

The magnetic properties of the trinuclear Schiff base complexes M2UL⁷ (MII=Co, Ni, Cu; L⁷=N,N’‐bis(3‐hydroxysalicylidene)‐2,2‐dimethyl‐1,3‐propanediamine), exhibiting the [M(μ‐O)2]2U core structure (3d‐5 f‐3d subsystem), have been investigated theoretically using scalar relativistic ZORA/DFT computations combined with the broken symmetry (BS) appro...

This study explores the distinctive behavior of protactinium (Z=91) within the actinide series. In contrast to neighboring elements like uranium or plutonium, protactinium in the pentavalent state diverges by not forming the typical dioxo protactinyl moiety PaO2⁺ in aqueous phase. Instead, it manifests as a monooxo PaO³⁺ cation or a Pa⁵⁺. Employing...

The correct interpretation of magnetic properties in the weak-exchange regime has remained a challenging task for several decades. In this regime, the effective exchange interaction between local spins is quite...

This study explores the distinctive behavior of Protactinium (Z = 91) within the actinide series. In contrast to neighboring elements like uranium or plutonium, Protactinium in the pentavalent state diverges by not forming the typical dioxo pro- tactinyl moiety PaO2^{+} in aqueous phase. Instead, it manifests as a monooxo PaO^{3+} cation. Employing...

The bond distance is the simplest and most obvious indicator of the nature of a given chemical bond. However, for rare chemistry, it may happen that it is not yet...

This study explores the distinctive behavior of Protactinium (Z = 91) within the actinide series. In contrast to neighboring elements like uranium or plutonium, Protactinium in the pentavalent state diverges by not forming the typical dioxo pro- tactinyl moiety PaO2^{+}. Instead, it manifests as a monooxo PaO^{3+} cation. Employing first-principle...

Protactinium (Z = 91) exhibits a distinct behaviour among the actinides. Unlike its neighbors uranium, neptunium or plutonium in the pentavalent oxidation state, it does not form the dioxo protactinyl moiety PaO2^{+}, but it can exist in the form of a monooxo PaO^{3+} cation. In this article, with the standard first-principle calculations and by in...

Protactinium (Z = 91) exhibits a distinct behaviour among the actinides. Unlike its neighbors uranium, neptunium or plutonium in the pentavalent oxidation state, it does not form the dioxo protactinyl moiety PaO2^{+}, but it can exist in the form of a monooxo PaO^{3+} cation. In this article, with the standard first-principle calculations and by in...

Polonium (Po, Z = 84) is a main-block element with poorly known physico-chemical properties. Not much information has been firmly acquired since its discovery by Marie and Pierre Curie in 1898, especially regarding its speciation in aqueous solution and spectroscopy. In this work, we revisit the absorption properties of two complexes, [PoCl5]- and...

This chapter is dedicated to the rationalization of magnetic anisotropy in metal complexes. Analytical derivations allow one to predict the nature and magnitude of both the zero-field-splitting and the anisotropies of magnetic exchange. The first section is devoted to mononuclear complexes. It addresses the effect of spin–orbit coupling (SOC) in tw...

Polonium (Po, Z = 84) is a main-block element with poorly known physico-chemical properties. Not much information has been firmly acquired since its discovery by Marie and Pierre Curie in 1898, especially regarding its speciation in aqueous solution and spectroscopy. In this work, we revisit the absorption properties of two complexes, [PoCl5]^- and...

Protactinium (Z = 91) is a very rare actinide with peculiar physico-chemical properties. Indeed, although one may naively think that it behaves similarly to either thorium or uranium by its position in the periodic table, it may in fact follow its own rules. Because of the quite small energy gap between its valence shells (in particular the 5f and...

The magnetic properties of trinuclear Schiff base complexes M2AnLi (MII = Zn, Cu; AnIV = Th, U; Li = Schiff base; i = 1-4, 6, 7, 9), exhibiting the [M(μ-O)2]2U core structure with adjacent M1···U and M2···U and next-adjacent M1···M2 interactions, featuring 3d-5f-3d subsystems, have been investigated theoretically using relativistic ZORA/B3LYP compu...

Protactinium (Z = 91) is a very rare actinide with peculiar physico-chemical properties. Indeed, although one may naively think that it behaves similarly to either thorium or uranium by its position in the periodic table, it may in fact follow its own rules. Because of the quite small energy gap between its valence shells (in particular the 5f and...

This chapter is devoted to theoretical calculations aimed at determining the electronic structure of binuclear complexes, including isotropic and anisotropic interactions in both the strong and in the weak-exchange coupling limits. The theory of effective Hamiltonians is used to extract magnetic anisotropy terms in various regimes and in particular...

Polonium (Z = 84) is one of the rarest elements on Earth. More than a century after its discovery, its chemistry remains poorly known and even basic questions have not yet been satisfactorily addressed. In this work, we perform a systematic study of the geometries, interactions energies and bonding in basic polonium(IV) species, namely the hydrated...

Polonium (Z = 84) is one of the rarest elements on Earth. More than a century after its discovery, its chemistry remains poorly known and even basic questions are not yet satisfactorily addressed. In this work, we perform a systematic study of the geometries, interactions energies and bonding in basic polonium(IV) species, namely the hydrated [Po(H...

The Pourbaix diagram of an element displays its stable chemical forms with respect to the redox potential and pH of the solution, whose knowledge is fundamental for understanding and anticipating the chemistry of the element in a specified solution. Unlike most halogens, the Pourbaix diagram in the aqueous phase for astatine (At, Z = 85) is still u...

The antisymmetric exchange, also known as the Dzyaloshinskii-Moriya interaction (DMI), is an effective interaction that may be at play in isolated complexes (with transition metals or lanthanides, for instance), nanoparticles, and highly correlated materials with adequate symmetry properties. While many theoretical works have been devoted to the an...

The Dzyaloshinskii Moriya interaction is expected to be at the origin of interesting magnetic properties, such as multiferroicity, skyrmionic states and exotic spin orders. Despite this, its theoretical determination is far from being established, neither from the point of view of ab initio methodologies, nor from that of the extraction technique t...

As a non-covalent interaction, halogen bonding is now acknowledged to be useful in all fields where the control of intermolecular recognition plays a pivotal role. Halogen-bond basicity scales allow quantification of the halogen bonding of referential donors with organic functional groups from a thermodynamic point of view. Herein we present the pK...

Uranium trioxide, UO3, has a T-shaped structure with bent uranyl, UO22+, coordinated by an equatorial oxo, O2-. The structure of cation UO3+ is similar but with an equatorial oxyl, O•-. Neutral and cationic uranium trioxide coordinated by nitrates were characterized by collision induced dissociation (CID), infrared multiple-photon dissociation (IRM...

Magnetic anisotropy, in the absence of an external magnetic field, relates to the degeneracy lift of energy levels. In the standard case of transition metal complexes, this property is usually modeled by an anisotropic spin Hamiltonian and one speaks of "zero-field splitting" (ZFS) of spin states. While the case of mononuclear complexes has been ex...

This paper is a theoretical “proof of concept” on how the on-site first-order spin–orbit coupling (SOC) can generate giant Dzyaloshinskii–Moriya interactions in binuclear transition metal complexes. This effective interaction plays a key role in strongly correlated materials, skyrmions, multiferroics, and molecular magnets of promising use in quant...

The chemistry of linear uranyl(V/VI) dioxo cations, [Oyl–U–Oyl]+/2+, is dominated by coordination of uranium in the equatorial plane. Effects of this constraint were evaluated by experiment and theory for gas‐phase mixed‐valence UV/VI coordination dimers in which uranyl moieties are linked by alkyl dicarboxylates, [(UO2⁺)(UO2²⁺)(OOC‐(CH2)n‐2‐COO2–)...

We report a methodology that allows the investigation of the consequences of the spin–orbit coupling by means of the QTAIM and ELF topological analyses performed on top of relativistic and multiconfigurational wave functions. In practice, it relies on the “state‐specific” natural orbitals (NOs; expressed in a Cartesian Gaussian‐type orbital basis)...

The halogen bond is a powerful tool for the molecular design and pushing the limits of its strength is of major interest. Bearing the most potent halogen‐bond donor atom, astatine monoiodide (AtI) was recently successfully probed [Nat. Chem. 2018, 10, 428–434]. In this work, we continue the exploration of adducts between AtI and Lewis bases with th...

Scalar and spin-dependent relativistic effects can influence the geometries and wave functions of the ground and excited states of molecular systems in a way that is not always trivial. However, it is still common for researchers, in particular within the quantum chemistry community, to neglect the spin-dependent effects while discussing the bindin...

More than a hundred years after its discovery, the chemistry of the polonium radioelement is still largely unknown. However, it is quite clear that the properties of this heavy element ( Z = 84) may be affected by relativistic effects, in particular scalar relativistic effects and the so-called spin-orbit coupling (SOC). In this Article, we revisit...

A Schiff base ligand resulting from the reaction of ovanillin and 2,2-dimethyl-1,3-diaminopropane allows preparation of hetero-dinuclear [Ni-Ln]3+ or -trinuclear [Ni-Ln-Ni]3+ complexes. Although empirical parameters for rationalizing the strength of the ferromagnetic Ni-Gd interaction have been already discussed in several papers, no systematic stu...

The importance of halogen bonds-highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base-is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, impl...

Zero-field splitting (ZFS) is one of the essential ingredients for the occurrence of magnetic bistability at a molecular level. It is commonly understood as the loss of degeneracy of the spin components of a spin-orbit free electronic state in the absence of an external magnetic field. The loss of degeneracy finds its origin in the combined action...

Hypervalent XF3 (X = Cl, Br, I, At) fluorides exhibit T-shaped C2V equilibrium structures with the heavier of them, AtF3 , also revealing an almost isoenergetic planar D3h structure. Factors explaining this behavior based on simple "chemical intuition" are currently missing. In this work, we combine non-relativistic (ClF3 ), scalar-relativistic and...

At is a most promising radionuclide for targeted alpha therapy. However, its limited availability and poorly known basic chemistry hamper its use. Based on the analogy with iodine, labelling is performed via astatobenzoate conjugates, but in vivo deastatination occurs, particularly when the conjugates are internalized in cells. Actually, the chemic...

Evidencing new chemical species in solution is particularly challenging when one works at ultra-trace concentrations, as is likely to happen with radioelements such as astatine (Z=85). Herein, quantum mechanical calculations were used to predict the narrow experimental domain in which it is possible to detect the presence of an exotic ternary triha...

Evidencing new chemical species in solution is particularly challenging when one works at ultra-trace concentrations, as is likely to happen with radioelements such as astatine (Z=85). Herein, quantum mechanical calculations were used to predict the narrow experimental domain in which it is possible to detect the presence of an exotic ternary triha...

The AtO(+) cation is one of the main chemical forms that appear in the astatine Pourbaix diagram. This form can react with closed-shell species in solution, while in the gas phase, it has a spin-triplet ground spin-orbit-free (SOF) state. Spin-orbit coupling (SOC) mixes its MS = 0 component with the (1)Σ(+) singlet-spin component, while keeping an...

A central goal of chemistry is to achieve ultimate oxidation states, including in gas-phase complexes with no condensed phase perturbations. In the case of the actinide elements, the highest established oxidation states are labile Pu(VII) and somewhat more stable Np(VII). We have synthesized and characterized gas-phase AnO3(NO3)2(-) complexes for A...

This work addresses the question of the identification of the excited states that are mainly responsible for the magnitude and nature of the magnetic anisotropy in high-spin mononuclear transition metal complexes. Only few states are actually responsible for the single ion magnetic anisotropy, and these states can be anticipated from rather simple...

Metal–organic frameworks, which are a special case of coordination polymers, form a class of materials with numerous applications due to their high porosities and large internal surface areas and in some cases also due to paramagnetic metal ions. A family of such materials of general formula M2(dobdc) (where M is a divalent metal ion, and dobdc4– i...

The main-group 6p elements did not receive much attention in the development of recent density functionals. In many cases it is still difficult to choose among the modern ones a relevant functional for various applications. Here, we illustrate the case of astatine species (At, Z = 85) and we report the first, and quite complete, benchmark study on...

The application of 211At to targeted cancer therapy is currently hindered by the rapid deastatination that occurs in vivo. As the deastatination mechanism is unknown, we tackled this issue from the viewpoint of the intrinsic properties of At-involving chemical bonds. An apparent correlation has been evidenced between in vivo stability of 211At-labe...

It is generally assumed that astatide (At(-) ) is the predominant astatine species in basic aqueous media. This assumption is questioned in non-complexing and non-reductive aqueous solutions by means of high-pressure anion-exchange chromatography. Contrary to what is usually believed, astatide is found to be a minor species at pH=11. A different sp...

The presence of open metal sites along with a high porosity makes the Fe2(dobdc) metal-organic framework, also called Fe-MOF-74, particularly well suited for separating gaseous mixtures. For instance, since Fe2(dobdc) adsorbs O2 more strongly than N2, it can, in principle, be used to separate O2 from air [ Bloch et al. J. Am. Chem. Soc. 2011, 133,...

The potential energy surfaces of the group 17 XF3 (X = Cl, Br, I, At) fluorides have been investigated for the first time with multiconfigurational wave function theory approaches. In agreement with experiment, bent T-shaped C 2v structures are computed for ClF3, BrF3, and IF3, while we predict that an average D 3h structure would be experimentally...

Magnetic anisotropy is responsible for the single molecule magnet behavior of transition metal complexes. This behavior is characterized by a slow relaxation of the magnetization for low enough temperatures, and thus for a possible blocking of the magnetization. This bistable behavior can lead to possible technological applications in the domain of...

The nature of chemical bonds in heavy main-group diatomics is discussed from the viewpoint of effective bond orders, which are computed from spin-orbit wave functions resulting from spin-orbit configuration interaction calculations. The reliability of the relativistic correlated wave functions obtained in such two-step spin-orbit coupling framework...

Gas-phase plutonium nitrate anion complexes were produced by electrospray ionization (ESI) of a plutonium nitrate solution. The ESI mass spectrum included species with all four of the common oxidation states of plutonium: Pu(III), Pu(IV), Pu(V), and Pu(VI). Plutonium nitrate complexes were isolated in a quadrupole ion trap and subjected to collisio...

In benzophenone, intersystem crossing occurs efficiently between S1(nπ*) and the T1 state of dominant nπ* character, leading to excited triplet states after photoexcitation. The transition mechanism between S1(nπ*) and T1 is still a matter of debate, despite several experimental studies. Quantum mechanical calculations have been performed in order...

Carbon dioxide adsorption isotherms have been computed for the metal–organic framework (MOF) Fe2(dobdc), where dobdc4– = 2,5-dioxido-1,4-benzenedicarboxylate. A force field derived from quantum mechanical calculations has been used to model adsorption isotherms within a MOF. Restricted open-shell Møller–Plesset second-order perturbation theory (ROM...

The participation of the valence orbitals of actinides in bonding has been debated for decades. Recent experimental and computational investigations demonstrated the involvement of 6p, 6d and/or 5f orbitals in bonding. However, structural and spectroscopic data, as well as theory, indicate a decrease in covalency across the actinide series, and the...

A systematic study has been undertaken to determine how local distortions affect the overall (molecular) magnetic anisotropies in binuclear complexes. For this purpose we have applied a series of distortions to two binuclear Ni(II) model complexes and extracted the magnetic anisotropy parameters of multispin and giant-spin model Hamiltonians. Furth...

A multidentate, ligand platform is introduced that enables the isolation of both homo- and heterobimetallic complexes of divalent first-row transition metal ions such as Mn(II), Fe(II), and Co(II). By using a two-step metallation strategy, five bimetallic coordination complexes were synthesized with the general formula MMCl(py3tren), where py3tren...

The determination of anisotropic magnetic parameters is a task of both experimental and theoretical interest. The added value of theoretical calculations can be crucial for analyzing experimental data by (i) allowing assessment of the validity of the phenomenological spin Hamiltonians, (ii) allowing discussion of the values of parameters extracted...

Laser ionization of AnC4 alloys (An = Th, U) yielded gas-phase molecular thorium and uranium carbide cluster cations of composition AnmCn(+), with m = 1, n = 2-14, and m = 2, n = 3-18, as detected by Fourier transform ion-cyclotron-resonance mass spectrometry. In the case of thorium, ThmCn(+) cluster ions with m = 3-13 and n = 5-30 were also produc...

The metal-organic framework Fe2(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate), often referred to as Fe-MOF-74, possesses many interesting properties such as a high selectivity in olefin/paraffin separations. This compound contains open-shell Fe(II) ions with open coordination sites which may have large single-ion magnetic anisotropies,...

By many-body quantum-chemical calculations, we investigate the role of two structural effects—local ligand distortions and the anisotropic Cd-ion coordination—on the magnetic state of Cd2Os2O7, a spin S=3/2 pyrochlore. We find that these effects strongly compete, rendering the magnetic interactions and ordering crucially dependent on these geometri...

This paper reports the experimental and theoretical investigations of two trigonal bipyramidal Ni(II) complexes, the [Ni(Me6tren)Cl](ClO4) 1 and [Ni(Me6tren)Br](Br) 2. High Field, High frequency Electron Paramagnetic Resonance spectroscopy performed on a single crystal of the [Ni(Me6tren)Cl](ClO4) 1 shows a giant uniaxial magnetic anisotropy with a...

The nature and magnitude of the magnetic anisotropy of heptacoordinate mononuclear Ni(II) and Co(II) complexes were investigated by a combination of experiment and ab initio calculations. The zero-field splitting (ZFS) parameters D of [Ni(H(2) DAPBH)(H(2) O)(2) ](NO(3) )(2) ⋅2 H(2) O (1) and [Co(H(2) DAPBH)(H(2) O)(NO(3) )](NO(3) ) [2; H(2) DAPBH=2...

The possible origin of the spiral spin structure in multiferroic LiCu2O2 is studied by calculating all relevant isotropic and anisotropic magnetic interactions in the material. The coupling constants are extracted from accurate ab initio quantum chemical calculations with an effective Hamiltonian theory. First, the anisotropic or Dzyaloshinskii-Mor...

Two novel mononuclear five-coordinate nickel complexes with distorted square-pyramidal geometries are presented. They result from association of a tridentate "half-unit" ligand and 6,6'-dimethyl-2,2'-bipyridine according to a stepwise process that highlights the advantage of coordination chemistry in isolating an unstable tridentate ligand by nicke...

Cupric oxide (CuO) has been described as belonging to the quasi-one-dimensional antiferromagnetic compounds. It has also been suggested that cupric oxide possesses strong magnetic anisotropy, which is possibly related to the observed ferroelectricity in this material. In this paper, the magnetic interactions of CuO are investigated using the embedd...

The synthesis of a new Ni(II)-Y(III) binuclear complex with a marked elongation axis in the first coordination sphere of the Ni(II) ion is presented. Its zero-field splitting (ZFS) is studied by means of magnetic data and state-of-the-art ab initio calculations. A good agreement between the experimental and theoretical ZFS parameter values is encou...

Pentagonal-bipyramidal complexes [Co(DABPH)X(H(2)O)]X [X = NO(3) (1), Br (2), I (3)] were synthesized, and their magnetic behavior was investigated. Simulation of the magnetization versus temperature data revealed the complexes to be highly anisotropic (D ≈ +30 cm(-1)) and the magnitude of the anisotropy to be independent of the nature of the axial...

The zero-field splitting of the copper acetate monohydrate complex is studied using wave function based calculations. The anisotropy parameters extracted from highly correlated methods are in excellent agreement with the most accurate experimental results; in particular, the negative sign of the axial anisotropy parameter D is reproduced. During se...

Magnetic anisotropy is responsible for the slow relaxation of the magnetization in single molecule magnets. The main goal of this work is to understand the factors that govern local and intersite anisotropies in polynuclear compounds. For this purpose, correlated relativistic calculations are performed in mono- and bi-nuclear species. The main degr...