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The association of lanthanide ions and paracyclophane derivatives has been very scarcely reported in the literature. In this study, elaboration of five coordination lanthanide complexes involving the 1,4(1,4)-dibenzenacyclohexaphane-12,43-diylbis(diphenylphosphine oxide) ligand (L) was achieved with the determination of single-crystal X-ray diffraction structures of four mononuclear complexes of formula [Ln(hfac)3(L)] (hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate) (Ln = Dy(III) (1-Dy) and Yb(III) (2-Yb)) and [Ln(tta)3(L)] (tta− = 2-tenoyl-trifluoroacetylacetonate) (Ln = Dy(III) (3-Dy) and Yb(III) (4-Yb)) and one dinuclear complex [Na(Dy2(hfac)6(L)2)](BArF) (BArF− = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) (5-Dy). The compounds were characterized using elemental analysis, IR spectroscopy, DC and AC magnetic measurements and photophysical investigations. L is an efficient organic chromophore for the sensitization of both visible Dy(III) (1-Dy) and near-infrared Yb(III) (2-Yb and 4-Yb) luminescence. The combination of excitation and emission spectra allowed the determination of the crystal field spitting of both the 2F7/2 ground state and 2F5/2 excited state for 2-Yb and 4-Yb. Moreover, 3-Dy and the two Yb(III) derivatives displayed field-induced single-molecule magnet (SMM) behaviour with slow magnetic relaxation occurring through the Raman process only for 2-Yb and 4-Yb, whereas a combination of Orbach and Raman processes was identified for 3-Dy. [ABSTRACT FROM AUTHOR]

The reaction between the ((E)-N′-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide) (H2opch) ligand and the metallo-precursor [Dy(hfac)3]·2H2O led to the formation of an homometallic coordination complex with the formula [Dy2(hfac)3(H2O)(Hopch)2][Dy(hfac)4] (1). In presence of both [Dy(hfac)3] 2H2O and the Fe(II) salt, the heterobimetallic tetranuclear [FeDy3(hfac)8(H2O)2(opch)2] (2) was isolated, while the addition of the co-ligand 1,2-Bis(2-hydroxy-3-methoxybenzylidene) hydrazine (H2bmh) led to the formation of two heterobimetallic tetranuclear complexes with the formula [Fe3Dy(hfac)6(opch)2(H2bmh)] C6H14 (3) C6H14 and [Fe2Dy2(hfac)7(opch)2(H2bmh)] 0.5C7H16 (4) 0.5C7H16. Single crystal X-ray diffraction and dc magnetic investigation demonstrated that 3 and 4 involved the iron center in the +II and +III oxidation states. Dynamic magnetic measurements highlighted the single-molecule magnet behavior of 1 and 2 in a zero applied dc field primarily due to the ferromagnetic interactions taking place in these compounds. [ABSTRACT FROM AUTHOR]

In this work, a new family of binuclear NiII–LnIII complexes with the formula [NiLn(L)2(NO3)3]·0.5H2O (Ln = Gd, 1; Tb, 2; Dy, 3; Ho, 4; Er, 5; Yb, 6; Y, 7) was synthesized using a thioether group-bearing Schiff base. Due to the strict hard/soft dichotomy between the 4f and 3d metal ions, selective coordination of NiII and 4f metal ions was achieved with the adjacent soft ONS and hard OO binding pockets of the ligand. All the complexes 1–7 exhibit a NiII centre in a distorted pseudo-octahedral geometry with the LnIII centres in distorted bicapped square-antiprism geometry. The huge distortion around the NiII centres is triggered for the accommodation of larger lanthanoids to the adjacent OO coordination site, and this forces the NiII centres to have a tridentate coordination from the ONS, as intermediate between meridional and facial binding. Field-induced single-molecule magnetic behaviour was observed for heterodinuclear complexes involving Kramers lanthanide ions (LnIII = Dy, Er and Yb), with magnetic relaxation occurring through an Orbach process only for 5. DFT calculations using various functionals (BP86, B3LYP, PBE0, TPSSh, PWPB95, R2SCAN) were applied to calculate the isotropic exchange, showing good agreement with the experiment (JGd–Ni = +1.78 cm−1). CASSCF calculations for NiII and LnIII ions were also performed to reveal detailed information about their electronic structure and magnetic anisotropy, supporting the experimental observations. This study accentuates the mutual distortion of coordination geometry induced by flexibility of the ligand backbone with the simultaneous binding of two different metal ions. [ABSTRACT FROM AUTHOR]

This paper investigates the reactivity and optical properties of transition metal-incorporated organoantimony(V) clusters prepared by a solvothermal route. The detailed structural characterization of novel heterometallic M2Sb4 oxo clusters is reported herein. Single crystal X-ray diffraction revealed the formation of hexanuclear organoantimony(V) based oxo clusters [(p-ClC6H4Sb)4V2(O)2(μ3-O)2(μ2-O)2(t-BuPO3)4(μ2-OCH3)4] (1), [M2(p-iPr-C6H4Sb)4(μ3-O)2(μ2-O)2(μ2-OCH3)4(t-BuPO3)4(py)2]·xCH3OH, where M = Mn, x = 2 (2), Co, x = 1 (3), Ni, x = 2 (4) and Cu, x = 2 (5). The magnetic behaviour of the clusters was probed by magnetic susceptibility measurements. Optical absorption studies showed that bandgap reduction can be achieved by incorporating an appropriate transition metal into the homometallic Sb6 oxo cluster. [ABSTRACT FROM AUTHOR]

Tetrathiafulvalenes (TTFs) functionalized with groups able to increase non-covalent intermolecular interactions through either hydrogen, halogen or chalcogen bonding were investigated. For that purpose, we designed several appropriate precursors, fused dithiole-2-one/thiazoles, which under homocoupling led to symmetrically substituted TTFs or through heterocoupling to dissymmetrically substituted TTFs. The electrochemical investigations allowed the assessment of the electronic effect of these substituents on the overall donating ability of the TTFs. In addition two charge transfer salts have been prepared involving two of these TTFs with TCNQF4 as the electron acceptor, (4c)2(TCNQF4) and (4b)(TCNQF4). Furthermore the crystal structures of the neutral TTFs and of the charge transfer salts allowed us to study the stacking mode and the different non-covalent interactions taking place in the crystals, in connection with the calculated electrostatic surface potential (ESP) of the investigated molecules. All the data provide information about non-covalent bonding interactions in the solid state and about their potential contribution to direct to some extent crystallographic intermolecular organization. [ABSTRACT FROM AUTHOR]

The interest for chiral tris(β‐diketonato)lanthanide complexes in coordination chemistry is huge due to its Lewis acid character, optical activity, and the control of the final compound architecture. The reaction of equimolar quantities of [Dy((−)/(+)hfc)3(H2O)] (hfc− = 3‐(heptafluoropropylhydroxymethylene)‐(+/−)‐camphorate) and L led to the formation of a pair of enantiomers for dinuclear complexes [Dy((−)/(+)hfc)3(L)]2⋅C7H16([(−)/(+)1]⋅C7H16) (L = 4′‐(4′′′‐pyridyl‐N‐oxide)‐1,2′:6′1′′‐bis‐(pyrazolyl)pyridine]). Starting from the previous experimental protocol with the addition of bulky BArF anions, a partial dissociation of the chiral [Dy((−)/(+)hfc)3(H2O)] was observed leading to the isolation of a mono‐dimensional cationic chiral polymer {[Dy((−)/(+)hfc)2(L)][BarF]}n⋅nCH3NO2([(−)/(+)2]n⋅nCH3NO2). Natural circular dichroism (NCD) highlighted an exciton CD couplet for [(−)/(+)2]n but not for (−)/(+)1. The latter behaves as a single‐molecule magnet (SMM) with a blocking temperature up to 4 K, whereas [(−)/(+)2]n is a 1D assembly of field‐induced SMMs with a magnetic relaxation occurring through a Raman process only. [ABSTRACT FROM AUTHOR]