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The combination of physical properties sensitive to molecular chirality in a single system allows the observation of fascinating phenomena such as magneto‐chiral dichroism (MChD) and circularly polarized luminescence (CPL) having potential applications for optical data readout and display technology. Homochiral monodimensional coordination polymers of YbIII were designed from a 2,15‐bis‐ethynyl‐hexahelicenic scaffold decorated with two terminal 4‐pyridyl units. Thanks to the coordination of the chiral organic chromophore to Yb(hfac)3 units (hfac−=1,1,1,5,5,5‐hexafluoroacetylaconate), efficient NIR‐CPL activity is observed. Moreover, the specific crystal field around the YbIII induces a strong magnetic anisotropy which leads to a single‐molecule magnet (SMM) behaviour and a remarkable room temperature MChD. The MChD‐structural correlation is supported by computational investigations. [ABSTRACT FROM AUTHOR]

Research has been conducted on the relation between the structural and magnetic properties. The synthesis of the molecular materials which have both Cotton effects and ferromagnetic long range order has been carried out in investigating this relation and the results are presented.

Three new binuclear FeIII–LnIII complexes, with similar structures, have been synthesized using the end-off compartmental proligand, H2valpn, resulting from the Schiff condensation between o-vanillin and 1,3-propylenediamine: [FeIIILnIII(valpn)(hfac)2(OAc)Cl] (Ln = Gd, Tb, Dy; hfac− = hexafluoroacetylacetonate; AcO− = acetate). The metal ions are triply bridged by two phenoxido oxygen atoms and by the acetato ligand (syn–syn bridging mode). Among all these compounds the FeIII–LnIII exchange interaction was found to be ferromagnetic (JFeGd = +1.004(4) cm−1; H = −J S Fe S Gd). The [FeIIIDyIII] derivative shows field-induced slow relaxation of the magnetization. The interpretation of the magnetic properties for the [FeIIIGdIII], [FeIIITbIII] and [FeIIIDyIII] is done through ab initio calculations. It was concluded that the temperature behavior of the relaxation time in the [FeIIIDyIII] derivative is due to dominant Orbach relaxation processes between states at the opposite sides and opposite heights of the blocking barrier. From this understanding, the relaxation mechanism for similar systems where a transition metal is in exchange coupling with a strong anisotropic lanthanide ion is elucidated, which could provide a strategy to synthesize other binuclear complexes with better magnetic properties. [ABSTRACT FROM AUTHOR]

The exchange channels governing the experimentally reported coupling constant (Jexpt=6 cm-1) value in the verdazyl-ligand based Cu(II) complex [Cu(hfac)2(imvdz)] are inspected using wave function-based difference dedicated configuration interaction calculations. The interaction between the two spin 1/2 holders is summed up in a unique coupling constant J. Nevertheless, by gradually increasing the level of calculation, different mechanisms of interaction are turned on step by step. In the present system, the calculated exchange interaction then appears alternatively ferromagnetic/antiferromagnetic/ferromagnetic. Our analysis demonstrates the tremendously importance of some specific exchange mechanisms. It is actually shown that both parts of the imvdz ligand simultaneously influence the ferromagnetic behavior which ultimately reaches Jcalc=6.3 cm-1, in very good agreement with the experimental value. In accordance with the alternation of J, it is shown that the nature of the magnetic behavior results from competing channels. First, an antiferromagnetic contribution can be essentially attributed to single excitations involving the π network localized on the verdazyl part. In contrast, the σ ligand-to-metal charge transfer (LMCT) involving the imidazole moiety affords a ferromagnetic contribution. The distinct nature σ/π of the mechanisms is responsible for the net ferromagnetic behavior. The intuitively innocent part of the verdazyl-based ligands is deeply reconsidered and opens new routes into the rational design of magnetic objects. [ABSTRACT FROM AUTHOR]

The absence of centrosymmetry in the enantiopure chiral magnet [N(C[H.sub.3])[(n-[C.sub.3][H.sub.7]).sub.2](C*H(C[H.sub.3])[C.sub.2][H.sub.5])[[Mn.sup.II][Cr.sup.III][(ox).sub.3]] has shown the bulk of second harmonic generation (SHG) in this material. The variation of the signal with the orientation of the magnetic field and the angle between the polarization of the incident radiation and the outgoing SHG signal in the paramagnetic and ferromagnetic phases is reproduced and understood by using a symmetry-based analysis of the nonlinear susceptibility tensor.

Ab initio Wave-function-based calculations were performed to understand the structure and magnetic behavior of the verdazyl-based radical [M[(hfac).sub.2][imvd.sup.0] complexes containing open-shell transition metal ions (where M = Mn, Ni; hfac = (1,1,1,5,5,5)hexafluoro-acetylacetonate; imvd = 3-(2'-imidazolyl)-1,5-dimethyl-6-oxoverdazyl). The dominant [pi]* donor and spin-polarized characteristics of the verdazyle moiety over the negligible polarizability of the imidazole part indicated that the noninnocent nature of the imvd radical is held by the verdazyl ring part.

The synthesis and structural characterization of the 3-(2'-imidazolyl)-1,5-dimethyl-6-oxoverdazyl radical (imvd) and the corresponding tetrazane [H.sub.3]imvd are described. The studies have shown that this radical has provided reduced steric hindrance, potential bridging ability upon deprotonation of the imidazole group and stepwise construction of the desired compound through controlled deprotonation of this group.

The syntheses of templated assembly of [[Ru.sup.II][(bpy).sub.3]]- [[Pd.sup.II.sub.2][(ox).sub.3]], Pd2 and [[Ru.sup.II][(bpy).sub.3]][[Pd.sup.II][Mn.sup.II][(ox).sub.3]], PdMn are described. X-ray absorption spectroscopy results revel an unusual 6-fold oxygen environment around the Pd(II) atoms and due to this palladium(II) has a triplet (S=1) ground state.