Lithium cations in a self-assembled electrostatic nanocapsule

Cascade self-assembly of small components, without the employment of preformed hosts, yielded a {Ni12Li2} nanometric capsule with multiple endo- and exo-guests (water molecules, Li+, and Et3NH+ cations) linked to selective hydrophilic and hydrophobic binding sites of NiII hexanuclear metallamacrocycles. The synthesis was achieved by using (Bu4N)N3 as a starting reagent instead of the conventional sodium azide to selectively introduce the Li+ cations

Chiroptical and magnetic properties of star-shaped Fe-4(III) complexes from chiral Schiff bases. Structural and magnetic correlations based on continuous shape measures

New chiral Fe-4(III) star-shaped complexes have been synthesized starting from enantiomerically pure Schiff bases and chiroptically and magnetically characterized. The structural and magnetic properties of the complete family of 40 Fe-4 complexes reported in the literature have been analyzed in the search for synthetic and magnetostructural correlations

Anionic guests in prismatic cavities generated by enneanuclear nickel metallacycles

The combination of polydentate aminated ligands with the 2-pyridyloxime-nickel-azide system leads to series of clusters with unprecedented topologies. Among them, a remarkable family of {Ni9} metallacycles that are capable of selective encapsulation of azide/halide anions in a cryptand-like cavity through hydrogen-bond interactions has been characterized

Na2MnIII6 LnIII clusters with a non-equivalent core: chiral vs. meso isomerism

A wide family of clusters with the Na2MnIII6 LnIII core derived from an enantiomerically pure or a racemic mixture of Schiff bases lead to the characterization of a unique case of chiral/meso isomers with C3/D3d symmetry respectively, involving the rearrangement of the cluster bond parameters and the change from hepta- to hexacoordination of the central LnIII cation

Linked Nickel Metallacrowns from a Phosphonate/2-Pyridyloximate Blend of Ligands: Structure and Magnetic Properties

In the present work, four new NiII clusters with nuclearities ranging between Ni4 and Na2Ni8 were synthesized, employing the versatile ligand phenylphosphonate and 6-methylpyridylaldoximate as the coligand. Crystallographic data show that the tetranuclear complex [Ni 4 (6-MepaoH)4(PhPO3)2(OH)2(MeOH)4](OH)2 (1) consists of two dimers linked by phosphonate bridges, whereas [Cs2Ni6(6-Mepao)6(PhPO3)3(OH)2(H2O)8] (2), Cs[Ni8(6-MepaoH)6(6-Mepao)6(PhPO3)3](ClO4)5 (3), and [Ni8Na2(BzO)6(6-Mepao)6(PhPO3)3] (4) are built from phosphonato-linked {Ni3(6-Mepao)3} metallacycles. The [9-MCNiII(6‑Mepao)-3] fragments in 2−4 show the unusual coordination of additional Cs+, Na+ , and/or NiII cations. Direct-current magnetic measurements were carried in the 300−2 K range. Analysis of the experimental data revealed a complex response with strong antiferromagnetic interactions mediated by the oximato bridges and weak interactions mediated by the phosphonate ones

Template arrangement of {Ni3(&m3-OH)(SO4)(R-NO)2}+ fragments around Na+ cations: An unprecedented {Ni12Na} unit linked by oximate and sulfate bridges

Anovel {−Ni12Na2-Ni-}n chain has been characterized fromthe reaction between 2-pyridylcyanoxime, (pyC{CN}NOH), and nickel(II) sulfate. The template synthesis around a Na+ cation gives an unprecedented arrangement of four nickel triangles coordinated to the central sodium ion by sulfato bridges

Enhancement of magnetic relaxation properties with 3d diamagnetic cations in [ZnIILnIII] and [NiIILnIII], LnIII=Kramers lanthanides

Employing the chiral bi-compartmental Schiff-base ligand H2L obtained from the condensation of (RR) or (SS)-1,2-diphenyl-ethylenediamine and o-vanillin, we report the structural characterization of the discrete dinuclear pairs of enantiomers [NiIIEuIII] 1RR, 1SS and [ZnIIEuIII] 2RR, 2SS and the magnetic properties for the series of complexes [NiIILnIII], Ln = Ce, 3RR; Nd, 4RR; Dy, 5RR; Er, 6RR, Yb, 7SS and [ZnIILnIII], Ln = Ce, 8RR; Nd, 9RR; Dy, 10SS; Er, 11SS and Yb, 12RR in which MII is diamagnetic and LnIII is a Kramers lanthanide. Single crystal X-ray diffraction shows that relevant changes in the [ZnIILnIII] structures are produced after a period in open air (2RRb, 2RRc), evidencing that the lability of the ligands bonded to ZnII can modify the structures that will be correlated to the experimental measurements. The dynamic magnetic measurements showed that the [NiIILnIII] and [ZnIILnIII] derivatives exhibit different behaviors in the relaxation of magnetization especially for oblate and prolate LnIII cations

Chiral Oxazolidine Complexes Derived from Phenolic Schiff Bases

Schiff bases derived from pyridyl- or salicyl-aldehydes and aminoalcohols can evolve to heterocyclic oxazolidines, which in the presence of cations allow the formation of uncommon coordination compounds. In this work, we report new NiII and mixed valence MnII/ MnIV complexes derived from pyridyl oxazolidines and the unprecedented characterization of enantiomerically pure oxazolidines derived from the condensation of o-vanillin with phenylglycinol in the presence of NiII cations. The different reactivity of the pyridinic or phenolic Schiff bases has been compared, and the new systems have been structurally, optically, and magnetically characterized

Chiral mononuclear lanthanide complexes derived from chiral Schiff bases: Structural and magnetic studies

A new family of mononuclear lanthanide complexes with formula [LnIII(L)Cl3] (Ln = Eu (1), Tb (2), Dy (3), Er (4), Yb (5)) and L = N,N0-bis((1,2-diphenyl-(pyridine-2-yl)methylene)-(R,R/S,S)-ethane-1,2-diamine has been obtained employing enantiomerically pure Schiff bases. The complexes have been structurally characterized using X-ray single crystal and powder diffraction. Their dynamic magnetic properties have been studied showing that this family presents slow relaxation of the magnetization under certain conditions and confirms the different behavior of each LnIII cations in isostructural complexes: only the Er one possibly relaxing via an overbarrier Orbach process, while Raman process dominates for Dy and Yb derivative

Decanuclear FeIII clusters with hemiacetal ligands: a new{M10(μ3-O)8} cluster core

The characterization of a decanuclear FeIII cluster with α-methyl- 2-pyridinemethanolate, generated by the hydrolysis of Schiff bases, inspired us to carry out an initial exploration of the direct syntheses of medium nuclearity FeIII clusters starting from aldehydes in methanolic medium. The new complexes exhibit an unprecedented {Fe10(μ3-O)8} cluster core