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Engineering high-recognition host-guest materials is a burgeoning area in basic and applied research. The challenge of exploring novel porous materials with advanced functionalities prompted us to develop dynamic crystalline structures promoted by soft interactions. The first example of a pure molecular dynamic crystalline framework is demonstrated, which is held together by means of weak "sticky fingers" van der Waals interactions. The presented organic-fullerene-based material exhibits a non-porous dynamic crystalline structure capable of undergoing single-crystal-to-single-crystal reactions. Exposure to hydrazine vapors induces structural and chemical changes that manifest as toposelective hydrogenation of alternating rings on the surface of the [60]fullerene. Control experiments confirm that the same reaction does not occur when performed in solution. Easy-to-detect changes in the macroscopic properties of the sample suggest utility as molecular sensors or energy-storage materials.

Engineering high-recognition host-guest materials is a burgeoning area in basic and applied research. The challenge of exploring novel porous materials with advanced functionalities prompted us to develop dynamic crystalline structures promoted by soft interactions. The first example of a pure molecular dynamic crystalline framework is demonstrated, which is held together by means of weak "sticky fingers" van der Waals interactions. The presented organic-fullerene-based material exhibits a non-porous dynamic crystalline structure capable of undergoing single-crystal-to-single-crystal reactions. Exposure to hydrazine vapors induces structural and chemical changes that manifest as toposelective hydrogenation of alternating rings on the surface of the [60]fullerene. Control experiments confirm that the same reaction does not occur when performed in solution. Easy-to-detect changes in the macroscopic properties of the sample suggest utility as molecular sensors or energy-storage materials.

This work introduces a novel family of CoII species having a curcuminoid (CCMoid) ligand, 9Accm, attached, namely [Co(9Accm)2(py)2] (1) and [Co(9Accm)2(2,2'-bpy)] (2), achieved in high yields by the use of a microwave reactor, and exhibiting two different arrangements for the 9Accm ligands, described as "cis"(2) and "trans"(1). The study of the similarities/differences of the magnetic, luminescent and surface behaviors of the two new species, 1 and 2, is the main objective of the present work. The determined single-crystal structures of both compounds are the only CoII-CCMoid structures described in the literature so far. Both compounds exhibit large positive D values, that of 1 (D = +74 cm-1) being three times larger than that of 2 (D = +24 cm-1), and behave as mononuclear Single-Molecule Magnets (SMMs) in the presence of an external magnetic field. Their similar structures but different anisotropy and SMM characteristics provide, for the first time, deep insight on the spin-orbital effects thanks to the use of CASSCF/NEVPT2 calculations implementing such contributions. Further magnetic studies were performed in solution by means of paramagnetic 1H NMR, where both compounds (1 and 2) are stable in CDCl3 and display high symmetry. Paramagnetic NMR appears to be a useful diagnostic tool for the identification of such molecules in solution, where the resonance values found for the methine group (-CH-) of 9Accm vary significantly depending on the cis or trans disposition of the ligands. Fluorescence studies show that both systems display chelation enhancement of quenching (CHEQ) with regard to the free ligand, while 1 and 2 display similar quantum yields. Deposition of 1-2 on HOPG and Si(100) surfaces using spin-coating was studied using AFM; UV photoemission experiments under the same conditions display 2 as the most robust system. The measured occupied density of states of 2 with UV photoemission is in excellent agreement with theoretical DFT calculations.

This work introduces a novel family of CoII species having a curcuminoid (CCMoid) ligand, 9Accm, attached, namely [Co(9Accm)2(py)2] (1) and [Co(9Accm)2(2,2'-bpy)] (2), achieved in high yields by the use of a microwave reactor, and exhibiting two different arrangements for the 9Accm ligands, described as "cis"(2) and "trans"(1). The study of the similarities/differences of the magnetic, luminescent and surface behaviors of the two new species, 1 and 2, is the main objective of the present work. The determined single-crystal structures of both compounds are the only CoII-CCMoid structures described in the literature so far. Both compounds exhibit large positive D values, that of 1 (D = +74 cm-1) being three times larger than that of 2 (D = +24 cm-1), and behave as mononuclear Single-Molecule Magnets (SMMs) in the presence of an external magnetic field. Their similar structures but different anisotropy and SMM characteristics provide, for the first time, deep insight on the spin-orbital effects thanks to the use of CASSCF/NEVPT2 calculations implementing such contributions. Further magnetic studies were performed in solution by means of paramagnetic 1H NMR, where both compounds (1 and 2) are stable in CDCl3 and display high symmetry. Paramagnetic NMR appears to be a useful diagnostic tool for the identification of such molecules in solution, where the resonance values found for the methine group (-CH-) of 9Accm vary significantly depending on the cis or trans disposition of the ligands. Fluorescence studies show that both systems display chelation enhancement of quenching (CHEQ) with regard to the free ligand, while 1 and 2 display similar quantum yields. Deposition of 1-2 on HOPG and Si(100) surfaces using spin-coating was studied using AFM; UV photoemission experiments under the same conditions display 2 as the most robust system. The measured occupied density of states of 2 with UV photoemission is in excellent agreement with theoretical DFT calculations.

In this paper we report the microwave assisted synthesis and characterization of a family of Na−Ln coordination polymers (CPs) of formula [NaDy2(MeCOO)2(SALOH)5(chpH)2] (1Ln, Ln=Eu, Gd, Tb, Dy, Ho, Y). The Na+ cations isolate Ln2 units in a one‐dimensional polymer. By changing the lanthanoid ions, we attain Single Molecule Magnet properties (1Dy), luminescent properties (1Eu, 1Tb, 1Ho), a diamagnetic material (1Y) and a material that presents magnetocaloric effect (1Gd). [ABSTRACT FROM AUTHOR]

Gd complexes have been studied as magnetic coolants due to their large magneto-caloric effect. In this work we present a Gd 2D metal–organic framework (MOF) of formula [Gd(MeCOO)(PhCOO)2] (1). We characterize the magnetic properties of 1, showing that it displays slow relaxation of the magnetization by ac susceptibility, and single-ion magnetic anisotropy using high-field EPR. By heat capacity and magnetization vs. field at various temperatures we determine the magnetic entropy change of compound 1. We then grow 1 on functionalized silicon, and show that the surface-deposited 2D MOF 1Si can be used as an on-surface magnetic cryogenic coolant. [ABSTRACT FROM AUTHOR]

The design of dynamic structures with high recognition host‐guest materials capable to host selectively small volatile molecules is an emergent field of research with both fundamental and applied implications. The challenge of exploring novel materials with advanced functionalities has led to the development of dynamic crystalline structures promoted by soft interactions. Here, a new pure organic dynamic framework based on hexakis[60]fullerene that are held together by weak van der Waals interactions is described. This crystalline structure is capable of absorbing and releasing chloroform, through internal structural reorganization. This research provides new insight into the design of organic molecular crystals for selective adsorption applications. [ABSTRACT FROM AUTHOR]

For some time, the presence of high oxidation state Mn ions and Ca(II) in the active center of Photosystem II has been known. However, coordination complexes that combine both Mn(III) and Ca(II) have been difficult to obtain, with only a handful of examples reported. In this paper we report the synthesis of two new Mn(III)-Ca(II) complexes, 1 [Pr2NH2]3[Mn6CaO2(OH)(OMe)3(SALO)6 (SALOH)3] and 2 [Mn18Ca6O12(OH)6(MeO)12(PhCOO)18(MeOH)6]. The complexes have been characterized by single-crystal X-ray diffraction to establish the oxidation state of manganese. The use of salicylato ligands with tert-butyl substituents leads to effective encapsulation of a Ca(II) ion in a cavity that has both hydrophobic and hydrophilic regions, mimicking the enzyme environment. [ABSTRACT FROM AUTHOR]