Neodymium 1D systems: targeting new sources for field-induced slow magnetization relaxation

Two non-isostructural homometallic 1D neodymium species dis- playing field-induced slow magnetization relaxations are presented together with theoretical studies. It is established that both systems are better described as organized 1D single molecule magnets (SMMs). Studies show great potential of NdIII ions to provide homometallic chains with slow magnetic relaxation

Anion-controlled geometrically different Cu(II) ion-based coordination polymers and green synthetic route for copper nanoparticles: a combined experimental and computational insight

<p>The Cu(II) ion-based polymeric complexes [Cu(2,2′-bpy).(N₃)₂]_n (<b>I</b>), [Cu₂(2,2′-bpy)₂.(N₃)₄]_n (<b>II</b>), and monomeric complex [Cu(2,2′-bpy).(NO₃)₂].5H₂O (<b>III</b>) have been synthesized with rigid (–N₃) and aromatic (2,2′-bpy = 2,2′-bipyridyl) ligand. The rigid azide group is responsible for the formation of 1-D extended structures in complexes <b>I</b> and <b>II</b> where as in the case of complex <b>III</b>, a monomeric complex is formed due to lack of a bridging group like –N₃, resulting in limitation in dimensionality. The thermal stability of the 1-D complexes is comparatively higher than monomeric complex <b>III</b>. Hirshfeld surface analysis has also been applied to investigate other weak interactions and compared with the results from single-crystal X-ray data. Due to the presence of paramagnetic metal centers and long metal···metal distances in complexes <b>I</b> and <b>II</b> and presence of lattice water molecules in complex <b>III</b>, decrease in luminescence intensities have been observed. To attain further insights into the aforementioned interesting species, some chemical concepts such as highest occupied molecular orbital–lowest unoccupied molecular orbital gap, electronic chemical potential, chemical hardness, and electrophilicity index, identified as a derivative of electronic energy, have also been emphasized employing the quantum chemical calculations in the framework of the density functional theory method using the M06-2X/ 6-31G** level of study. Further, these complexes have been used to synthesize copper nanoparticles by applying a green synthetic route.</p

Structural Diversity, Thermal Studies, and Luminescent Properties of Metal Complexes of Dinitrobenzoates: A Single Crystal to Single Crystal Transformation from Dimeric to Polymeric Complex of Copper(II)

Seventeen complexes of 3,5- and 2,4-dinitrobenzoates (<b>L1</b>–<b>L2</b>) with alkali, alkaline, and transition metals have been synthesized and characterized by the single crystal X-ray diffraction, IR spectroscopy, elemental analysis, and thermal studies. Diverse structural topologies have been achieved due to various coordination modes of the benzoates, resulting in five new topologies. Interesting architectures such as zero-dimensional (0D) monomers and paddle-wheel dimers; pseudocubane, double helices, ladders and linear one-dimensional (1D) tapes; pseudodiamondoid and brick-wall type two-dimensional (2D); and chiral three-dimensional (3D) networks were generated. The latter three are formed by the coparticipation of −NO₂ groups in the coordination, while 1D complexes are formed by the coordination of water/solvent. Thermogravimetric analysis studies show that the 3D complexes are more stable than 2D; however, 1D complexes become more stable than 2D after the loss of the solvent. The effects of positional isomerism and the nature of the metal ions on the topology also have been observed. The ligands are nonemissive but nine complexes have shown a moderate amount of photoluminescence, owing to the rigidity conferred by the crystal structure of the complex, which largely reduces the radiation less decay and results in enhancement of the intensity of the ligand to ligand charge transfer (LLCT) band. A relatively much larger photoluminescence in the polymeric complex (<b>VIII</b>) of copper­(II), however, is a combination of enhanced LLCT due to the double helical 1D crystal structure and chelation enhanced fluorescence (CHEF) phenomenon. A single crystal to single crystal supramolecular transformation of a paddle-wheel complex of copper­(II) with guest solvent molecules in the lattice to a desolvated 1D polymer is achieved for the Cu<b>L1</b> complex. Because of self-assembly, six of these complexes crystallize as homochiral, single, double, or triple helical conglomerates, which constitute the most active expression of chirality

Role Reversal of the Carboxylate Group from Coordination to Hydrogen Bonding Only, in Structurally Diverse Metal-2-amino,5-Nitro-benzoates: A First Report

The remarkable structural diversities arising from a small ligand, 2-amino,5-nitro-benzoic acid <b>(L1H</b>), equipped with different functional groups, conferring tunable coordination sites as well as H-bonding abilities, have been explored. Six new crystal structures of Cs­(I), Na­(I), K­(I), and Li­(I) ions with <b>L1</b> have been realized. Notably, for the medium-sized alkali metal ions, a role reversal between the coordination and H-bonding nature of −COO^– and −NO₂ groups, respectively, has been observed for the first time. Since <b>L1</b> possesses three potential sites for coordination as well as H-bonding interactions, we realized a delicate control of noncovalent interactions on the resulting supramolecular assemblies. Structural diversities observed range from one-dimensional helices and linear threads to two-dimensional brick-wall types or three-dimensional networks. The electrostatic surface potential (ESP) of three representative complexes provided an insight into the electronic-deficient and electron-rich regions. The coordination of Na­(I) and K­(I) ions through the nitro groups extends the electron-deficient region of the complexes. The electron densities at the bond critical paths of the representative complexes were calculated to understand the supramolecular outcome of the coordination polymers. Unravelling of such critical electronic information is paramount toward the systematic construction of a new generation of complex coordination polymers

Electrochemical Post-Ugi Cyclization for the Synthesis of Highly Functionalized Spirolactams

The combination of the Ugi reaction and electro-organic synthesis can aid in the creation of novel heterocycles that have not been previously explored. In this study, a new strategy utilizing bis-amides from the Ugi reaction has been developed, which can produce C–S, C–Se, and C–CO functionalized five-membered spirolactams mediated by electricity under catalyst- and metal-free conditions. Notably, this approach can be applied using a microelectro-flow reactor (μ-EFR) for gram-scale synthesis. The described strategy can synthesize complex azaspiro-fused tricyclic scaffolds with high diastereo- and regioselectivity, highlighting its versatility and potential