Search

A series of new halogenated bis(acenaphthylene)dione (BAN) derivatives was synthesized, and the effect of halogen bonding on both molecular and crystal structure, and charge transport in n-type thin film transistors was investigated.

Location controlled symmetry reduction of the tetracarboxy porphyrin linker by altering the position of the coordinating groups leads to the design of a novel reduced symmetry linker 5,15-bis(p-carboxyphenyl)-10,20-bis(m-carboxyphenyl)porphyrin (H4-TpmCPP). The corresponding crystalline coordination framework Gd-TpmCMPF was synthesized by employing the NaOH modulator approach. The resulting compound is an 8-connected network with a bcu topology and two different perforated 1D channels. The consequence of reduced symmetry is highlighted in the geometry of capsular void spaces formed between porphyrin moieties in the framework which allows coordination with formate ions in the reaction mixture.

This study targets the construction of porphyrin-based supramolecular assemblies directed by hydrogen bonds, by utilizing the free-base tetratopic 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin, and a series of N-containing monodentate and bidentate heterocycles (pyridine, 4,4′-bipyridine, 4,4′-bipyridylethene and phenazine) as building units. The component moieties contain attractive combinations of complementary molecular recognition functions for the formation of porphyrin only or porphyrin-N-heterocycle supramolecular organic frameworks (SOFs). Seven new crystalline materials could be synthesized and structurally characterized in this effort. Some of these supramolecular assemblies exhibit efficient inclusion of guests with a large aromatic backbone (pyrene and perylene). The optical properties of the available materials were also probed by solid state UV-vis diffuse reflectance spectroscopy (DRS).

New crystalline lanthanoid–metalloporphyrin porous frameworks [(Zn(H2O)–OCPP)Ln2(H2O)4Na2]n·solvent (Ln = Sm, Eu, Gd, Tb, and Dy) (LnMPF-1) were synthesized from an octatopic tetrakis-(3,5-dicarboxyphenyl)porphyrin building block through a synthetic approach using NaOH as a modulator to enhance the robustness of the metal–organic-framework (MOF) product and the formation of sizeable crystals. The formulated MOFs adopt a (4,8)-connected topology and are perforated by 1D tubular zigzag channels of about 1.5 nm in diameter. The frameworks possess permanent porosity and display appealing photophysical properties.

This paper addresses a series of recent investigations into crystalline porphyrin-based assemblies directed by non-covalent and non-coordinative interactions. It describes attractive design strategies for the formulation of multi-dimensional aggregates of suitably activated poly-topic porphyrins, without the use of metal ion connectors. The major part of the discussion relates to open porphyrinic networks supported by cooperative halogen bonding and hydrogen bonding interaction synthons, highlighting the crystal-engineering toolbox available to this end.

Nine new coordination polymers of 5-substituted nicotinic acid (with either –Br, HBNA, or –COOH, 3,5-H2PDC) with d-transition (Co, Ni, Zn and Cd) and f-lanthanoid (La, Ce, Sm and Tb) metal ions have been synthesized. The two metal complexes [Co2(BNA)4(H2O)]n·H2O (1a) and [Cd(BNA)2]n (1b) have polymorphic/isomeric structures to those of metal–organic-frameworks (MOFs) with similar structural building units (SBUs) reported earlier. Modified reaction conditions yielded new isomeric metal complexes in the present case. Reactions of the 3,5-H2PDC linker with different metal ions led to the formation of polymeric complexes [Mn3(3,5-PDC)3(DMA)3]n·DMA (2a), [Zn(3,5-PDC)(DMA)]n·DMA (2b) and [Cd2(3,5-PDC)2(DMA)4]n (2c), as well as lanthanoid MOFs [Sm(3,5-PDC)1.5(DMF)]n·DMF (2d, as well as isomorphous products with La (2f) and Ce (2g) ions) and [Tb2(3,5-PDC)3(DMF)2]n·DMF (2e). Networking diversity observed in these coordination polymers with the conformationally rigid 5-substituted nicotinic acid ligand is discussed. The magnetic properties of 2a, 2d and 2e have been studied as well.

Four new framework solids consisting of coordination polymers [Cd2(L)(H2O)2(DMA)]n (1), [Cu2(L)(H2O)2]n (2), [Co2(L)(H2O)5]n (3) and [Mn2(L)(H2O)5]n (4) (H4L = 5-(3,5-dicarboxybenzyloxy)isophthalic acid; DMA = dimethyl acetamide) have been synthesized under hydro(solvo)thermal conditions and characterized by X-ray crystallography. In all cases, the metal-ion connectors consist of di-nuclear clusters. The fully de-protonated flexible tetradentate organic linker assumes a flat conformation with laterally oriented carboxylate functions in 1 and 2, but a twisted conformation with one carboxyphenyl residue rotated by nearly 90° with respect to the other in the isomorphous structures of 3 and 4. The resulting polymeric metal–organic lattices in 1 and 2 are perforated by wide (accounting for more than 50% of the crystal volume) solvent-accessible channel voids. In 3 and 4 the organic linker is characterized by tetrahedral tetra-carboxylate functionality, inducing the formation of open polymeric architectures with diamondoid geometries which interweave into one another in the crystal to fill most of the empty space. The remaining voids are filled by molecules of water. Thermal analysis (TGA and DTA) features of 1–4, nitrogen gas sorption behavior of 2 and solid-state variable temperature magnetic susceptibility data of 3 and 4 are reported as well.

A series of new coordination polymers of the 5,5′-methylenebis(oxy)dinicotinic acid ligand with various metal ions, have been synthesized under hydro(solvo)thermal conditions and characterized by X-ray crystallography: [Co(L)(H2O)4]n (1), [Cu(L)(H2O)2]n (2), two polymorphs of [Cd(L)(H2O)]n·(DMA)n (3 and 4), [Co4(L)4(H2O)3]n·(acetonitrile)n (5), [Mn2(L)2(H2O)]n·(acetonitrile)n (6) and [Cd2(L)2(H2O)]n·(DMA)n·1½(H2O)n (7) (H2L = 5,5′-methylenebis(oxy)dinicotinic acid; DMA = dimethyl acetamide) The hybrid metal–organic polymeric assemblies reveal diverse connectivity and topological features in one-, two- and three-dimensions, depending on the number of ligation sites available on the metal centers for binding the organic ligands and the nuclearity of connecting nodes. Compounds 1–4 involve mono-nuclear metal connectors and represent 1D and 2D coordination polymers. The three-dimensional single-framework polymers in compounds 5–7 are tessellated via dinuclear coordination nodes. Solid-state variable temperature magnetic susceptibility data of 5 and 6 involving the paramagnetic Co(II) and Mn(II) ions are reported as well. They reveal week anti-ferromagnetic coupling between the proxime metal centers observed in these two complexes.

Five new framework solids consisting of coordination polymers [Cd3(L)2(H2O)2(DMA)2(H2O)]n (1), [Cu3(L)2(H2O)2]n (2), [Co3(L)2(H2O)6]n (3), [Mn3(L)2(H2O)5(DMF)]n (4), and [Ni3(L)2(H2O)6]n (5) (H3L = 5-(3,5-dicarboxybenzyloxy)-3-pyridine carboxylic acid; DMA = dimethyl acetamide; DMF = dimethyl formamide) have been synthesized under hydro(solvo)thermal conditions and characterized by X-ray crystallography. The five compounds represent extended coordination-polymeric assemblies; double interweaving of the metal–organic frameworks has been observed in 3–5. A diverse metal–ligand coordination schemes have been observed, mono- (in 2–5), di- (in 2) and tri-nuclear (in 1). Thermal analysis (TGA and DTA) features of 1–5 and solid-state variable temperature magnetic susceptibility data of 3, 4 and 5 are reported as well. The magnetic susceptibility data reveal weak anti-ferromagnetic coupling between the metal centers in these complexes.

This study evaluates the versatile supramolecular reactivity of the title dicarboxylic ligand (BFDC), via hydrogen bonding towards complementary organic ligands, and via metal–ligand coordination with various metal ions. Fourteen new crystalline compounds have been obtained and their structures characterized by single-crystal X-ray diffraction. BFDC was found to form trimeric 2 : 1 hydrogen-bonded assemblies with bipyridyl moieties, associated with the transfer of two protons from the diacid to the bipyridyl. Reactions of the BFDC with d- and f-transition metal ions yielded either 2 : 2 (dimeric) or 4 : 2 (tetrameric) discrete dinuclear metal–ligand complexes, as well as one-dimensional coordination polymers in which the diacid entities act as multidentate bridging ligands between adjacent metal ions along the polymeric backbone. The large diversity of the obtained products suggests that in the experimental conditions used, it seems practically impossible to predict the outcome of a given reaction. All the compounds were crystallized from aqueous environments and exhibit extended arrays of intermolecular hydrogen bonding.