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The synthesis and characterization of the new family of binuclear acetylide complexes featuring electron-rich Cp*(dppe)Fe(C[triple bond]C) (where dppe = 1,2-bis(diphenylphosphino)ethane) end groups connected by carbon-silicon hybrid connectors are described. The studies have shown the importance of the [sigma]-[pi] conjugation between the Si-Si [sigma] bond and the adjacent C[triple bond]C [pi]-symmetric orbitals in the description of the electronic structure of the ground states of these new compounds.

The description of a novel anionic hybrid carbonyl-telluride cobalt cluster belonging to the rare type of pentagonal-prismatic [M.sub.10] polyhedral geometry is presented. It is observed that the interactions of the CO-bridging half-shell with [[Cp*].sub.2]Nb[(CO).sub.2].sup.+] cations gives rise to the formation of supramolecular networks containing ribbons of anions and cations.

The mononuclear single-molecule magnet (SMM) [Dy(tta)3(L)]·C6H14 (1) (where tta = 2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazolemethyl- 2-pyridine) was studied by spectro-electrochemistry. The resulting electronic spectra of the three oxidation states 1, 1+·, and 12+ were rationalized by time-dependent density functional theory (TD-DFT) calculations starting from the DFT optimized structures. The modulation of the magnetic anisotropy of the DyIII center upon oxidation was also inspected at the Complete Active Space Self-Consistent Field (CASSCF) level of calculation. [ABSTRACT FROM AUTHOR]

The coordination of a helicene‐functionalized bipyridine to various lanthanide complexes (Ln = Y, Eu, Yb, Gd) led to the formation of an isostructural series. The photophysical study indicated that non‐emissive lanthanides act as heavy atoms strongly enhancing singlet oxygen generation. We also demonstrated that sensitization of the f‐f luminescence is in competition with singlet oxygen generation. The coordination of a helicene functionalized bipyridine to various lanthanide complexes (ln = Y, Eu, Yb, Gd) led to the formation of an isostructural series. The photophysical study indicated that lanthanides act as heavy atoms strongly enhancing the singlet oxygen generation. We also demonstrated that the sensitization of the f‐f luminescence is in competition with the singlet oxygen generation. [ABSTRACT FROM AUTHOR]

Molecular materials that possess a toroidal moment associated to a non‐magnetic ground state are known as single‐molecule toroics (SMTs) and are usually planar molecules. Herein, we report a Dy4 cubane, namely [Dy4(Bppd)4(μ3‐OH)4(Pa)4(H2O)4]⋅0.333 H2O (where BppdH=1,3‐Bis(pyridin‐4‐yl)propane‐1,3‐dione and PaH=2‐Picolinic acid) for which magnetometry measurements and state‐of‐art ab initio calculations highlight SMT behavior in a tridimensional structure (3D‐SMT). The in‐depth theoretical analysis on the resulting low‐lying energy states, along with their variation in function of the magnetic exchange pathways, allows further light to be shed on the description of single‐molecule toroics and identify the coupling scheme that better reproduces the observed data. 3D magnetic toroics: Molecular materials that have a toroidal moment associated to a non‐magnetic ground state are known as single‐molecule toroics (SMTs) and are usually planar molecules. Such a toroidal moment is observed in a Dy4 cubane, transposing this property to a tridimensional structure (3D‐SMT). [ABSTRACT FROM AUTHOR]

A series of four new homoleptic CoII, NiII, CuII and ZnII complexes (1–4) of the type M(HL)2, where HL– stands for the deprotonated form of the tridentate O,N,N‐donor Schiff base ligand obtained by condensation between 8‐hidroxy‐2‐quinolinecarboxaldehyde and 2‐aminophenol, have been prepared in yields ranging from 70 to 85 %. The five compounds were characterized using elemental analysis, FT‐IR, ESI‐MS, UV/Vis, and 1H and 13C NMR spectroscopy (for the diamagnetic species H2L and ZnII complex 4). The molecular structures of H2L and its NiII and ZnII complexes 2 and 4, respectively, were further confirmed by single‐crystal X‐ray diffraction methods. X‐ray crystal structure determination revealed that in complex 2, the six‐coordinate NiII metal ion adopts a N4O2 distorted octahedral geometry with the two tridentate HL– ligands coordinated in a perfect orthogonal fashion. In complex 4, however, the ZnII metal center is pentacoordinate and lies in a distorted N3O2 trigonal bipyramidal environment, one HL– ligand acting as an O,N‐bidentate ligand. In both cases, a free hydroxyl unit remains available for supramolecular interactions. Hirshfeld surface (HS) analysis along with 2D fingerprint plots were employed to consider the intermolecular forces, including hydrogen bonds and π–π stacking interactions, and their quantification in the crystal lattice. SQUID magnetometry experiments showed high spin CoII (S = 3/2), NiII (S = 1) and CuII (S = 1/2) isolated spins at room temperature with no interaction between magnetic centers on cooling. Four transition metal complexes bearing a O,N,N–donor 8‐hydroxylquinoline Schiff base ligand were efficiently synthesized, and their spectroscopic, structural, Hirshfeld surface and magnetic properties have been investigated. [ABSTRACT FROM AUTHOR]

The paramagnetic cluster [Cu43Al12](Cp*)12 was obtained from the reaction of [CuMes]5 and [AlCp*]4 (Cp*=η5‐C5Me5; Mes=mesityl). This all‐hydrocarbon ligand‐stabilized M55 magic atom‐number cluster features a Mackay‐type nested icosahedral structure. Its open‐shell 67‐electron superatom configuration is unique. Three unpaired electrons occupy weakly antibonding jellium states. The situation prefigures the formation of a conduction band, which is in line with the measured temperature‐independent magnetism. Steric protection by twelve Cp* ligands suppresses the intrinsic polyradicalar reactivity of the Cu43Al12 core. Superatomic: The reaction of [AlCp*]4 and [CuMes]5 yields the Mackay 55‐metal atom two‐shell icosahedral cluster [Cu43Al12](Cp*)12. The intermetalloid cluster has a unique 67‐electron open‐shell superatomic [Cu43Al12]12+ core, embedded inside an all‐hydrocarbon shell of twelve Cp*− ligands. Its electronic structure comprises a set of entangled HOMO und low‐lying LUMOs, prefiguring the formation of a conduction band. [ABSTRACT FROM AUTHOR]

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The single-crystal and powder absorption spectroscopy of the chain compound with the formula McCu(pba)(H2O)(sub 3).2H(sub 2)O abbreviated as MnCu, where pba = 1,3-propylenebis(oxamato) is described. The results obtained are compared to those obtained with other Mn(super II)Cu(super II) compounds and the complementarity between optical and magnetic properties are discussed.

The complexes [Ln2(hfac)6(L)]•nC6H14 (Ln = Dy (1) n = 0, Yb (2) n = 1) with the L chiral 3,14-di-(2-pyridyl)-4,13-diaza[6]helicene ligand (hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate) have been synthesized in their racemic form and structurally and magnetically characterized. Both complexes behave as field-induced single molecule magnets in the crystalline phase. These magnetic properties were rationalized by ab initio calculations. [ABSTRACT FROM AUTHOR]

Tetrathiafulvalene (TTF)-based ligands and lanthanide ions have been intensively used for their electronic conductivity and optical properties, respectively. Their combination leads to a new class of coordination compounds that are able to display single-molecule magnet (SMM) behavior. Magnetic bistability resulting of such behavior could find potential applications in high-density data storage and quantum computing. In this chapter, a library of TTF-based magnets containing lanthanide ions is presented. Among this series, the influence of the coordination sphere and intra- and intermolecular interactions such as exchange, dipolar, supramolecular, and hyperfine interactions is probed through molecular engineering, magnetic dilutions, and isotopic enrichment. [ABSTRACT FROM AUTHOR]

A new family of three DyIII mononuclear complexes and one DyIII chain system based on the same ligand [1,3‐di(pyridin‐4‐yl)propane‐1,3‐dione] has been isolated as single crystals. By varying the synthesis conditions, it has been possible to finely control the number of ligands coordinated to the central lanthanide atom (from 1 to 3) and then the total charge of the complex unit (from +2 to neutral), as well as the local geometry around the DyIII ion (from D4d to D2d). The magnetic properties of the four complexes have been studied and rationalized by ab initio calculations to illustrate the correlation between the metal‐ion environment, due to the number of coordinated ligands, and their SMM behaviours. [ABSTRACT FROM AUTHOR]

The two ligands 4‐[6‐(1,3‐benzothiazol‐2‐yl)pyridin‐3‐yl]‐4′,5′‐bis(methylthio)tetrathiafulvene (L1) and 4‐[6‐(1,3‐benzothiazol‐2‐yl)pyridin‐3‐yl]‐4′,5′‐(ethylenedithio)tetrathiafulvene (L2) were developed, and six new lanthanide coordination complexes, namely, [Ln2(hfac)6(L1)2]·C6H14·xCH2Cl2 [Ln = Dy and x = 0.25 (1); Ln = Yb and x = 0.30 (2); hfac– = 1,1,1,5,5,5‐hexafluoroacetylacetonate], [Ln(hfac)3(L2)] [Ln = Dy (3), Yb (4)] and [Ln(tta)3(L1)] [Ln = Yb (5), Er (6); tta– = 2‐thenoyltrifluoroacetylacetonate], were characterized by single‐crystal X‐ray diffraction. Compounds 1–6 were identified as mononuclear complexes, and the crystal packing depends on the natures of the ancillary and tetrathiafulvalene‐based ligands. The two dysprosium derivatives, 1 and 3, displayed single‐molecule‐magnet behaviour in zero applied magnetic field. Although the near‐infrared luminescence of 2 and 4 is almost undetectable, the change of ancillary ligand switched on the YbIII (5) and ErIII (6) luminescence. [ABSTRACT FROM AUTHOR]

Single‐molecule magnet (SMM) behavior of dysprosium‐based dimers was optimized by substitution of a DyIII ancillary ligand (hfac– in the previously reported DyPyNO and tta– in Dy). A clear hysteresis opening is visible at 0.5 K for Dy that allows for the determination of an antiferromagnetic (AF) coupling of –2.92 cm–1 (S = 1/2, gz = 19.58) which was confirmed by ab initio calculations. Comparison with the results of DyPyNO shows that stronger AF coupling correlates with better SMM behavior. This is further demonstrated by diamagnetic substitution, and a Y–Dy species (YDy) highlights that the strong AF magnetic interaction in Dy significantly enhances magnetic relaxation at low temperature. This coupling is also expected to be at the origin of the unexpectedly weak isotopic effect observed for the isotopically pure parents of Dy, namely 161Dy and 164Dy. [ABSTRACT FROM AUTHOR]

Keywords: Lanthanides; Magnetism; Molecular Switches; Photoluminescence; Sandwich Compounds EN Lanthanides Magnetism Molecular Switches Photoluminescence Sandwich Compounds 1 1 1 04/19/23 20230424 NES 230424 B Sandwich Compounds b . Lanthanides, Magnetism, Molecular Switches, Photoluminescence, Sandwich Compounds. [Extracted from the article]