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In this work, a novel complex, [Dy(L Pr )(NO 3 ) 2 ]·(H 2 O)·(NO 3 ) (1), containing a highly distorted macrocyclic ligand (L Pr ) and weak axial anions (NO 3 - ), was synthesized and characterized. Even though this coordination environment is not ideal for maximizing the magnetic anisotropy of a Dy III ion, a magneto-structural analysis reveals that the high distortion of the macrocycle promotes a disposition of the hard plane and easy axis opposite to the expected one. This results in a quite symmetrical environment which allows obtaining a field induced SMM behaviour. The magnetic relaxation properties of this complex were rationalized with the aid of ab initio multireference calculations. Moreover, 1 showed the characteristic emission bands of Dy III ion, indicating that the macrocyclic ligand acts as an efficient sensitizer in the energy transfer process to the emissive state of the Dy III ion. Due to the symmetric environment of 1, the Y/B intensity ratio (0.61) results in CIE coordinates (0.278; 0.314), close to those of the white light region. To gain further insight into the mechanism leading to the luminescence properties, ab initio calculations were performed to elucidate the key factors controlling the Y/B intensity ratio in this bifunctional complex.

Considering the structural design of some of the scarce molecular-based Er-centred emitters in the literature, we explored the optical properties of three Er III hexaazamacrocyclic complexes, namely Er-EDA (1), Er-OPDA(2) and Er-DAP(3). The macrocyclic ligands in these complexes differ in the lateral spacers, and are derived from 2,6-pyridine-dicarbaldehyde and ethylenediamine (EDA), ortho -phenylenediamine (OPDA) or 1,3-diaminopropane (DAP). Upon ligand-centred excitation, the bluish-green and green emissions of the Er III ion were detected only for the complexes containing macrocycles with aliphatic spacers (1 and 3), which evidenced that these ligands can sensitize the Er III luminescence. On the other hand, the ligand derived from the aromatic diamine (2) does not sensitize the Er III luminescence. Energy transfer mechanisms, temperature sensing, CIE coordinates and CCT values were analyzed. Besides the excitation in the ligands, the erbium-centred excitation at 980 nm allowed the detection, in all cases, of bluish-green, green and red up-converted emissions, and also the downshifted NIR emission. The possible mechanisms involved in these transitions were described and analyzed according to the available data.

A family of hexaazamacrocyclic lanthanide complexes, [Ln(Ln)(NCS)3] (LnIII = Dy, Er; n = 1-3) has been synthesized and characterized by single-crystal X-ray diffraction, magnetic measurements and ab initio calculations. Macrocyclic ligands (Ln) differ in the lateral spacers, which are aliphatic chains with two and three carbons (for Ln, n = 1 and 2, respectively), and an aromatic ring for Ln = 3. Modification of the macrocycle spacer tunes planarity and rigidity of the equatorial coordination for both oblate (Dy) and prolate (Er) lanthanide ions. Ac-susceptibility studies showed that four of the six complexes are field induced single molecule magnets (SMMs). Trends in magnetic relaxation properties are rationalized with the aid of ab initio multireference calculations, highlighting the combined influence of macrocycle planarity, lanthanide electronic density distribution and intermolecular interactions for the achievement of slow demagnetization.

Heterometallic 3d-4f inorganic polymers were prepared using 3,5 pyridinedicarboxylic acid (H2PDC), {[CuLn2(PDC)2(SO4)2(H2O)6]·H2O}n (Ln: SmIII, CuSmPDC, EuIII, CuEuPDC, GdIII, and CuGdPDC). These catalysts are active in the aerobic oxidation of cycloalkenes under solvent-free conditions, with a conversion for the oxidation of cyclohexene of 71% after one hour of the reaction, and a TOF value of 1438 h-1 for CuSmPDC. On the other hand, the oxidation of cycloheptene and cyclooctene exhibited slightly lower conversions of 52% and 47%, and TOF values of 1053 and 159 h-1 after 1 and 6 hours of the reaction, respectively. The radical mechanism for the oxidation reaction of cyclohexene was assessed by Raman and EPR spectroscopy. The first evidenced the formation of Cu-O2 adducts and the second permitted is to observe the presence of the oxygen centered radical species, which act as initiators of the reaction chain to generate the products. An increase in the temperature of the reaction correlates with the adduct formation, and with the enhancement of the oxidation reaction.

In this work the magnetic properties of bimetallic phases M' 0.2 Mn 0.8 PS 3 ·0.25H 2 O (M' = Co II , Ni II , Cu II or Zn II ) have been explored and compared with those of the pristine phase MnPS 3 . Magnetic susceptibility, high field magnetization and electron paramagnetic resonance (EPR) studies reveal that the transition temperature between the antiferromagnetic and paramagnetic order for the pristine phase is shifted to lower values in the bimetallic phases. From magnetization measurements the critical field of the spin-flop transition is found to be dependent on the nature of the added secondary transition metal ion. EPR spectra of all compounds in the temperature range of 8-300 K present a single resonance line shape. Temperature dependence of the EPR parameters, like line width, g values and double integrated area (I DIN ), are obtained from the spectra and present a scenario compatible with the magnetization results. The temperature dependence of the first derivative of the product (I DIN T) shows two maxima for all samples, with exception of the Co II phase, indicating two critical temperatures, while these critical temperatures could not be clearly determined by dc susceptibility.

M'0.2Mn0.8PS3·0.25H2O materials are obtained by a mild microwave assisted reaction (M' = Co(II), Ni(II), Cu(II), Zn(II)), which permitted us to obtain the first copper(ii) bimetallic phase. All these materials have a lower energy gap and antiferromagnetic interactions with lower values of the Weiss constant, than that of the pristine phase MnPS3.

In the present work, the synthesis and structural characterization of four new polyoxovanadoborate (BVO) frameworks based on the [V12B18O60H6](10-) polyanion are reported: (NH4)8(1,3-diapH2)[V12B18O60H6]·5H2O (1), K8(NH4)2[V12B18O60H6]·18H2O (2), K10[V12B18O60H6]·10H2O (3) and K8Cs2[V12B18O60H6]·10H2O (4). A global antiferromagnetic behaviour is observed for these 10V(IV)/2V(V) mixed valence clusters. The magnetic data of 1, 2 and 3, which present different countercation environments, show that 1 is more coupled than 2 and 3. DFT calculations show that the positive charges strongly influence the polarization mechanism of the spin density of the vanadyl groups and the extent of the magnetic orbitals, therefore corroborating the experimental observation of the quenching effect of the magnetic coupling between vanadium centres of 2 and 3.

A new extended metal-organic framework [Cu(H2btec)(bipy)]infinity. (1) (H4btec= 1,2,4,5-benzenetetracarboxylic acid; bipy = 2,2'-bipyridine) has been hydrothermally synthesized. Violet crystals are formed in a monoclinic system with a space group C2/c; a = 10.1810(18) A, b = 14.4360(18) A, c = 12.894(3) A, beta = 112.94(3) degrees. In the title compound 1 each Cu(II) centre has a distorted square planar environment, completed by two N atoms from one bipy ligand and two O atoms belonging to two dihydrogen benzene-1,2,4,5-tetracarboxylate anions (H2btec2-). The {Cu(bipy)}2+ moieties are bridged by H2btec2- anions to form an infinite one-dimensional coordination polymer with a zig-zag chain structure along the c axis. A double-chain structure is formed by hydrogen bonds between adjacent zig-zag chains. There are also pi-pi stacking interactions between the bipy ligands, with an average distance of 3.62 A resulting in a two-dimensional network structure. Compound 1 was tested as a catalyst for the oxidation of cyclohexene and styrene, with tert-butyl hydroperoxide (TBHP) as oxidant. The catalytic activity (24 h and 75 degrees C) found for [Cu(H2btec)(bipy)]infinity shows a high value for the conversion of cyclohexene (64.5%), and a lower one for styrene (23.7%). High turnover frequency (TOF) values for the epoxide products were observed, indicating that the catalyst synthesized in this work, not only has a high activity and selectivity for epoxidation reactions but is also very efficient.