Topological analysis of self-catenated motifs in coordination networks

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The Tip of Dendritic Crystal in an Inclined Viscous Flow

We study the flow around the tip of a dendritic crystal by an inclined stream of viscous incompressible liquid. The tip shape is chosen accordingly to recent theory [Phil. Trans. R. Soc. A 2020, 378, 20190243] confirmed by a number of experiments and computations [Phil. Trans. R. Soc. A 2021, 379, 20200326]. Our simulations have been carried out for a 0, 30, 60, and 90-degree flow slope to the dendrite axis. We show that the stream inclination has a significant effect on the hydrodynamic flow and shear stress. In particular, a transition from laminar to turbulent currents on the upstream side of the dendritic crystal may occur in an inclined hydrodynamic flow. This leads to the fact that the heat and mass transfer mechanisms on the upstream and downstream sides of a growing dendritic crystal may be different

Two Exceptional Patterns of Helical Secondary Building Units Found in Metal–Organic Framework Structures

We report the first example of a rod MOF in which the rod axes intersect. This suggests a new area of reticular chemistry in which helical rods that can be linked into frameworks are designed

Two Exceptional Patterns of Helical Secondary Building Units Found in Metal–Organic Framework Structures

We report the first example of a rod MOF in which the rod axes intersect. This suggests a new area of reticular chemistry in which helical rods that can be linked into frameworks are designed

Distinguishing Metal–Organic Frameworks

We consider two metal–organic frameworks as identical if they share the same bond network respecting the atom types. An algorithm is presented that decides whether two metal–organic frameworks are the same. It is based on distinguishing structures by comparing a set of descriptors that is obtained from the bond network. We demonstrate our algorithm by analyzing the CoRe MOF database of DFT optimized structures with DDEC partial atomic charges using the program package ToposPro

Topological Motifs in Cyanometallates: From Building Units to Three-Periodic Frameworks

This review focuses on topological features of three-periodic (framework) <i>p</i>, <i>d</i>, and <i>f</i> metal cyano complexes or cyanometallates, i.e. coordination compounds, where CN^– ligands play the main structure-forming role. In addition, molecular, one-periodic (chain), and two-periodic (layer) cyanometallates are considered as possible building blocks of the three-periodic cyanometallates. All cyanometallates are treated as systems of nodes (mononuclear, polynuclear, or transitional metal cluster complexes) joined together via CN-containing spacers. The most typical nodes and spacers as well as methods of their connection are described and systematized. Particular attention is paid to the overall structural motifs in the three-periodic cyanometallates, especially to the relations between the local coordination (coordination figure) of structural units and the entire framework topology. The chemical factors are discussed that influence the cyanometallate topological properties due to modification of nodes, spacers, or coordination figures

Big Spreadsheet of all the data from Pore topology analysis in porous molecular systems

Spreadsheet containing complete analysis of 1033 POS crystalstructure

Additional information from Pore topology analysis in porous molecular systems

Details of database generation and additional figure

Supramolecular architectures of Mn(NCS)2 complexes with N'-(1-(pyridin-4-yl)ethylidene)picolinohydrazide and N'-(phenyl(pyridin-4-yl)methylene)isonicotinohydrazide

In this work we have synthesized and characterized new mononuclear heteroleptic discrete complexes [Mn(NCS)(HL)(MeOH)] (1), [Mn(NCS)(HL)(EtOH)] (2) and [Mn(NCS)(HL)(EtOH)] (3), fabricated from Mn(NCS) and N'-(1-(pyridin-4-yl)ethylidene)picolinohydrazide (HL) and N'-(phenyl(pyridin-4-yl)methylene)isonicotinohydrazide (HL) in MeOH or EtOH. All the obtained complexes are structurally similar, while complexes 1 and 2 are isostructural. The metal center in all the structures is six-coordinated and in a NO geometry, formed by two monodentate ligands HL or HL, each exclusively linked through the 4-pyridil nitrogen atom, two N-coordinated NCS anions and two O-coordinated molecules of MeOH or EtOH. Crystal packing of 1 and 2 are mainly dictated by the intermolecular O[sbnd]H∙∙∙O hydrogen bonds, while the crystal packing of 3 is mainly driven by the intermolecular O[sbnd]H∙∙∙N hydrogen bonds. The structures of 1–3 reveal the uninodal 1D chains with the 2C1 topology, when complex molecules are considered as a node and O[sbnd]H∙∙∙O (in 1 and 2) of O[sbnd]H∙∙∙N (in 3) hydrogen bonds are considered. Considering remaining non-covalent interactions, the resulting topology can be extended up to a four-connected uninodal sql (Shubnikov tetragonal plane net) topology. The multilevel topological description of the molecular packing of 1–3, when all van der Waals interactions are considered, reveal that the structures of 1 and 2 are assembled from a linear chain through square lattice to different 3D frameworks, while the structure of 3, although starts from the same linear chain, produces 3D frameworks skipping 2D topologies. Molecular surfaces of 1–3 are mainly described by intermolecular H∙∙∙H, H∙∙∙C, H∙∙∙N, H∙∙∙O and H∙∙∙S contacts. Self-assembled supramolecular dimers observed in the solid state of all compounds have been studied using density functional theory (DFT) calculations, molecular electrostatic potential (MEP) surfaces and the NCIplot index. Moreover, the interaction energy of each individual hydrogen bond has been estimated using the quantum theory of «atoms-in-molecules» (QTAIM).E.V.A. is grateful to the Russian Science Foundation for supporting topological methods of crystal structure analysis with the program package ToposPro (Grant No. 18-73-10116). A.F. thanks the MICIU/AEI of Spain (project CTQ2017-85821-R FEDER funds) for financial support