Asymmetric [Dy2] molecules deposited into micro-SQUID susceptometers: characterization of their magnetic integrity.

The controlled integration of magnetic molecules into superconducting circuits is key to developing hybrid quantum devices. Herein, we study [Dy2] molecular dimers deposited into micro-SQUID susceptometers. The results of magnetic, heat capacity and magnetic resonance experiments, backed by theoretical calculations, show that each [Dy2] dimer fulfills the main requisites to encode a two-spin quantum processor.

Energy exchange between Nd and Er centers within molecular complexes.

Developing controlled and reproducible molecular assemblies incorporating lanthanide centers is a crucial step for driving forward up- and down-conversion processes. This challenge calls for the development of strategies to facilitate the efficient segregation of different Ln metal ions into distinct positions within the molecule. The unique family of pure [LnLn'Ln] heterometallic coordination compounds previously developed by us represents an ideal platform for studying the desired Ln-to-Ln' energy transfer (ET).

Self-assembly of a supramolecular spin-crossover tetrahedron.

A new mononuclear iron(II) SCO compound featuring H-bonding donor and acceptor units has been synthesized and exploited to produce a purely supramolecular switchable [Fe] tetrahedron. Magnetic and crystallographic measurements evidence a singular magnetic behavior for each of the four Fe(II) centers of the generated architecture and underscore the potential of this strategy to develop novel SCO materials.

Dynamics and local ordering of pentachloronitrobenzene: a molecular-dynamics investigation.

Plastic phases are constituted by molecules whose centers of mass form a long range ordered crystalline lattice, but rotate in a more or less constrained way. Pentachloronitrobenzene (PCNB) is a quasi-planar hexa-substituted benzene formed by a benzene ring decorated with a -NO group and five chlorine atoms that displays below the melting point a layered structure of rhombohedral (3̄) planes in which the molecules can rotate around a six-fold-like axis. Dielectric spectroscopy [Romanini , , 2016, , 10614] of this highly anisotropic phase revealed a complex relaxation dynamics with two coupled primary processes, initially ascribed to the in-plane and out-of-plane components of the molecular dipole.

Cytotoxicity of osmium(II) and cycloosmated half-sandwich complexes from 1-pyrenyl-containing phosphane ligands.

Five metal-arene complexes of formula [MX(η--cymene)(diR(1-pyrenyl)phosphane)] (M = Os or Ru, X = Cl or I, R = isopropyl or phenyl) and symbolized as were synthesized and fully characterized, namely , , , and . Furthermore, nine cyclometalated half-sandwich complexes of formula [MX-(η--cymene)(C-diR(1-pyrenyl)phosphane)] (M = Os or Ru, X = Cl or I, R = isopropyl or phenyl) or [M(η--cymene)(S-dmso)(C-diR(1-pyrenyl)phosphane)]PF (M = Os or Ru, R = isopropyl or phenyl) and symbolized as were prepared; hence, , , , , , , , and were obtained and fully characterized. The crystal structures of ten out of the fourteen complexes were solved.

Steric hindrance, ligand ejection and associated photocytotoxic properties of ruthenium(II) polypyridyl complexes.

Two ruthenium(II) polypyridyl complexes were prepared with the {Ru(phen)} moiety and a third sterically non-hindering bidentate ligand, namely 2,2'-dipyridylamine (dpa) and N-benzyl-2,2'-dipyridylamine (Bndpa). Hence, complexes [Ru(phen)(dpa)](PF) (1) and [Ru(phen)(Bndpa)](PF) (2) were characterized and their photochemical behaviour in solution (acetonitrile and water) was subsequently investigated. Compounds 1 and 2, which do not exhibit notably distorted octahedral coordination environments, contrarily to the homoleptic "parent" compound [Ru(phen)](PF), experience two-step photoejection of the dpa and Bndpa ligand upon irradiation (1050-430 nm) for several hours.

Distributive Nd-to-Yb Energy Transfer within Pure [YbNdYb] Heterometallic Molecules.

Facile access to site-selective hetero-lanthanide molecules will open new avenues in the search of novel photophysical phenomena based on Ln-to-Ln' energy transfer (ET). This challenge demands strategies to segregate efficiently different Ln metal ions among different positions in a molecule. We report here the one-step synthesis and structure of a pure [YbNdYb] () coordination complex featuring short Yb···Nd distances, ideal to investigate a potential distributive (, from one donor to two acceptors) intramolecular ET from one Nd ion to two Yb centers within a well-characterized molecule.

Unparalleled selectivity and electronic structure of heterometallic [LnLn'Ln] molecules as 3-qubit quantum gates.

Heterometallic lanthanide [LnLn'] coordination complexes that are accessible thermodynamically are very scarce because the metals of this series have very similar chemical behaviour. Trinuclear systems of this category have not been reported. A coordination chemistry scaffold has been shown to produce molecules of type [LnLn'Ln] of high purity, exhibiting high metal distribution ability, based on their differences in ionic radius.

Designed polynuclear lanthanide complexes for quantum information processing.

The design of dissymmetric organic ligands featuring combinations of 1,3-diketone and 2,6-diacetylpyridine coordination pockets has been exploited to produce dinuclear and trinuclear lanthanide-based coordination compounds. These molecules exhibit two or more non-equivalent Ln ions, most remarkably enabling the access to well-defined heterolanthanide compositions. The site-selective disposition of each metal ion within the molecular entities allows the study of each centre individually as a spin-based quantum bit, affording unparalleled versatility for quantum gate design.

Piano-Stool Ruthenium(II) Complexes with Delayed Cytotoxic Activity: Origin of the Lag Time.

We have recently reported a series of piano-stool ruthenium(II) complexes of the general formula [RuCl(η-arene)(P(1-pyrenyl)RR)] showing excellent cytotoxic activities (particularly when R = R = methyl). In the present study, new members of this family of compounds have been prepared with the objective to investigate the effect of the steric hindrance of a bulky phosphane ligand, namely diisopropyl(1-pyrenyl)phosphane (), on exchange reactions involving the coordinated halides (X = Cl, I). Two η-arene rings were used, i.

Accessing Lanthanide-to-Lanthanide Energy Transfer in a Family of Site-Resolved [Ln Ln '] Heterodimetallic Complexes.

The ligand H L (6-[3-oxo-3-(2-hydroxyphenyl)propionyl]pyridine-2-carboxylic acid), which exhibits two different coordination pockets, has been exploited to engender and study energy transfer (ET) in two dinuclear [Ln Ln '] analogues of interest, [EuYb] and [NdYb]. Their structural and physical properties have been compared with newly synthesised analogues featuring no possible ET ([EuLu], [NdLu], and [GdYb]) and with the corresponding homometallic [EuEu] and [NdNd] analogues, which have been previously reported. Photophysical data suggest that ET between Eu and Yb does not occur to a significant extent, whereas emission from Yb originates from sensitisation of the ligand.

A dissymmetric [Gd] coordination molecular dimer hosting six addressable spin qubits.

Artificial magnetic molecules can host several spin qubits, which could then implement small-scale algorithms. In order to become of practical use, such molecular spin processors need to increase the available computational space and warrant universal operations. Here, we design, synthesize and fully characterize dissymetric molecular dimers hosting either one or two Gadolinium(III) ions.

A heterometallic [LnLn'Ln] lanthanide complex as a qubit with embedded quantum error correction.

We show that a [Er-Ce-Er] molecular trinuclear coordination compound is a promising platform to implement the three-qubit quantum error correction code protecting against pure dephasing, the most important error in magnetic molecules. We characterize it by preparing the [Lu-Ce-Lu] and [Er-La-Er] analogues, which contain only one of the two types of qubit, and by combining magnetometry, low-temperature specific heat and electron paramagnetic resonance measurements on both the elementary constituents and the trimer. Using the resulting parameters, we demonstrate by numerical simulations that the proposed molecular device can efficiently suppress pure dephasing of the spin qubits.

Designed asymmetric coordination helicates with bis-β-diketonate ligands.

A new bis-(β-diketone) ligand featuring built-up structural asymmetry yields non-symmetric Fe(iii) and Ga(iii) dinuclear, triple-stranded helicates by design. Their structural properties have been studied, both in solid state and in solution, and compared with their corresponding symmetric analogues. The robustness observed shows the potential of this synthetic strategy to develop non-symmetric helicoidal motifs with specific functional groups.

Controlled Heterometallic Composition in Linear Trinuclear [LnCeLn] Lanthanide Molecular Assemblies.

The combination of two different β-diketone ligands facilitates the size-controlled assembly of pure heterometallic [LnLn'Ln] linear compounds thanks to two different coordination sites present in the molecular scaffold. [HoCeHo], [ErCeEr], and [YbCeYb] analogues are presented here and are characterized both in the solid state and in solution, demonstrating the selectivity of this unique method to produce heterometallic 4f molecular entities.

Zn Ion Surface Enrichment in Doped Iron Oxide Nanoparticles Leads to Charge Carrier Density Enhancement.

Here, we report the development of monodisperse Zn-doped iron oxide nanoparticles (NPs) with different amounts of Zn (Zn Fe O, 0 < < 0.43) by thermal decomposition of a mixture of zinc and iron oleates. The as-synthesized NPs show a considerable fraction of wüstite (FeO) which is transformed to spinel upon 2 h oxidation of the NP reaction solutions.

Selective Lanthanide Distribution within a Comprehensive Series of Heterometallic [LnPr] Complexes.

The preparation of heterometallic, lanthanide-only complexes is an extremely difficult synthetic challenge. By a ligand-based strategy, a complete isostructural series of dinuclear heterometallic [LnPr] complexes has been synthesized and structurally characterized. The two different coordination sites featured in this molecular entity allow study of the preferences of the praseodymium ion for a specific position depending on the ionic radii of the accompanying lanthanide partner.

Mn-Fe Heterometallic Compounds within Hydrogen-Bonded Supramolecular Networks Promoted by an [Fe(CN)(CNH)] Building Block: Structural and Magnetic Properties.

The reaction of [Fe(CN)] and [Mn(acacen)] (Hacacen = N, N'-bis(acetylacetone)ethylenediamine) building units in the presence of supramolecular cations, [(F-Anil)(18-crown-6)] (F-Anil = 3-fluoroanilinium) or [(Me-F-Anil)(18-crown-6)] (Me-F-Anil = 3-fluoro-4-methylanilinium), affords two new bimetallic compounds, [(F-Anil)(18-crown-6)][Mn(acacen)Fe(CN)(CNH)]·MeOH (1) and [(Me-F-Anil)(18-crown-6)][Mn(acacen)(MeOH)Fe(CN)(CNH)]·MeOH (2), respectively. Compound 1 exhibits a one-dimensional topology, while compound 2 is a dinuclear discrete system due to the coordination of a MeOH molecule at the axial position of the [Mn(acacen)] unit. For both systems, the acidity of the corresponding supramolecular cation triggers the protonation of the Fe moiety as [Fe(CN)(CNH)].

Spin State Chemistry: Modulation of Ligand p K by Spin State Switching in a [2×2] Iron(II) Grid-Type Complex.

The iron(II) [2×2] grid complex Fe-8H has been synthesized and characterized. It undergoes spin-crossover (SCO) upon deprotonation of the hydrazine-based terpyridine-like ligand. The deprotonation patterns have been determined by X-ray crystallography and H NMR spectroscopy and discussed in relation to the spin state of the iron(II) centers, which influences greatly the p K of the ligand.

Direct crystallographic evidence of the reversible photo-formation and thermo-rupture of a coordination bond inducing spin-crossover phenomenon.

A detailed crystallographic study of [Fe(LN)(CN)]·MeOH (LN = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene) shows the light-induced formation and thermally-assisted rupture of a metal-ligand coordination bond concomitantly with a spin-crossover process occurring at the Fe(ii) center between its low spin (LS) and high spin (HS) states.

Thermodynamic Stability of Heterodimetallic [LnLn'] Complexes: Synthesis and DFT Studies.

The solid-state and solution configurations of the heterodimetallic complexes (Hpy)[LaEr(HL) (NO )(py)(H O)] (1), (Hpy)[CeEr(HL) (NO )(py)(H O)] (2), (Hpy)[CeGd(HL) (NO )(py)(H O)] (3), (Hpy)[PrSm(HL) (NO )(py)(H O)] (4), and (Hpy) [LaYb(HL) (NO )(H O)](NO ) (5), in which H L is 6-(3-oxo-3-(2-hydroxyphenyl)propionyl)pyridine-2-carboxylic acid and py is pyridine, were analyzed experimentally and by using DFT calculations. Complexes 3, 4, and 5 are described here for the first time, and were analyzed by using single-crystal X-ray diffraction and mass spectrometry. The theoretical study was also extended to the [LaCe] and [LaLu] analogues.

Multifaceted magnetization dynamics in the mononuclear complex [ReCl(CN)].

The mononuclear complex (BuN)[ReCl(CN)]·2DMA (DMA = N,N-dimethylacetamide) displays intricate magnetization dynamics, implying Orbach, direct, and Raman-type relaxation processes. The Orbach relaxation process is characterized by an energy barrier of 39 K (27 cm) that is discussed based on high-field electron paramagnetic resonance (EPR), inelastic neutron scattering and frequency-domain THz EPR investigations.

Switchable Fe/Co Prussian blue networks and molecular analogues.

With the long term objective to build the next generation of devices from the molecular scale, scientists have explored extensively in the past two decades the Prussian blue derivatives and their remarkable physico-chemical properties. In particular, the exquisite Fe/Co system displays tuneable optical and magnetic behaviours associated with thermally and photo-induced metal-to-metal electron transfer processes. Recently, numerous research groups have been involved in the transfer of these electronic properties to new Fe/Co coordination networks of lower dimensionality as well as soluble molecular analogues in order to facilitate their manipulation and integration into devices.

Heterodimetallic [LnLn'] lanthanide complexes: toward a chemical design of two-qubit molecular spin quantum gates.

A major challenge for realizing quantum computation is finding suitable systems to embody quantum bits (qubits) and quantum gates (qugates) in a robust and scalable architecture. An emerging bottom-up approach uses the electronic spins of lanthanides. Universal qugates may then be engineered by arranging in a molecule two interacting and different lanthanide ions.

Linear or cyclic clusters of Cu(II) with a hierarchical relationship.

The polydentate ligand 2,6-bis(5-(2-hydroxyphenyl)-pyrazol-3-yl)-pyridine, H4L, exhibits a series of coordination pockets favoring the establishment of metal sequences with predetermined motifs, together with a degree of flexibility for the formation of clusters with various overall topologies. With Cu(II) under strong basic conditions it has a marked tendency to stabilize a cyclic [Cu16L8] cluster. The sequential formation of this compound via [Cu7L8](2-) intermediates, recognized in its structure, is suggested by crystallographic evidence, which shows the persistent formation of the complex salt (NBu4)2[Cu7L8] in the presence of the organic cation.