One-dimensional Supramolecular Chain Research Articles

In situ synthesis, crystal structure and photophysical properties of a new binuclear europium compound

A new europium compound [Eu2(H2O)8(MBA−)4](2MBA−) (1; MBA− = methylsulfanyl-benzoic acid anion) was synthesized via an in situ reaction of EuCl3·6H2O, 4,4′,4″-(1,3,5-triazine-2,4,6-triyltrisulfanediyl)tribenzoic acid, methanol and distilled water under hydrothermal conditions. The crystal structure is characterized by single-crystal X-ray diffraction and features a binuclear structure. The molecules are interlinked via hydrogen-bonding interactions to form a one-dimensional (1-D) supramolecular chain. A photoluminescence measurement with solid-state samples reveals that compound 1 can emit brown upconversion photoluminescence with the maximum peak locating at 622 nm and a weaker one at 590 nm. The bands are ascribed to the characteristic emission of the 4f electron intrashell transition of the 5D0 → 7F1 and 5D0 → 7F2 of the Eu3+ ions. Compound 1 exhibits CIE chromaticity coordinates (0.557, 0.4292) and its CCT is 1871 K. The solid-state diffuse reflectance spectra reveals that compound 1 has a bandgap of 4.09 eV.

Supramolecular self-assembly between symmetric tetramethyl cucurbit[6]uril and dimethylphenylpiperazine hydrochloride

The interaction between symmetric tetramethyl cucurbit[6]uril (TMeQ[6]) and 2,3-dimethylphenylpiperazine hydrochloride (PMY) has been studied in the presence of [CdCl4]2−. Each port of the TMeQ[6] is connected to PMY through weak interactions such as ion dipole interactions and CH⋯O hydrogen bonding interactions, whilst the [CdCl4]2− is connected with the portal carbonyl oxygen, glycoside urea methylene and a bridging methylene of a TMeQ[6] molecule via ion–dipole interactions. These interactions were evident from a single crystal X-ray diffraction study of TMeQ[6]-PMY-[CdCl4]2−. In addition, the complex can form a one-dimensional supramolecular chain structure, and then assemble into a two-dimensional supramolecular framework, which can be described as a TMeQ[6]-PMY-[CdCl4]2− based supramolecular framework (QSF).

105 K Wide Room Temperature Spin Transition Memory Due to a Supramolecular Latch Mechanism

Little is known about the mechanisms behind the bistability (memory) of molecular spin transition compounds over broad temperature ranges (>100 K). To address this point, we report on a new discrete FeII neutral complex [FeIIL2]0 (1) based on a novel asymmetric tridentate ligand 2-(5-(3-methoxy-4H-1,2,4-triazol-3-yl)-6-(1H-pyrazol-1-yl))pyridine (L). Due to the asymmetric cone-shaped form, in the lattice, the formed complex molecules stack into a one-dimensional (1D) supramolecular chain. In the case of the rectangular supramolecular arrangement of chains in methanolates 1-A and 1-B (both orthorhombic, Pbcn) differing, respectively, by bent and extended spatial conformations of the 3-methoxy groups (3MeO), a moderate cooperativity is observed. In contrast, the hexagonal-like arrangement of supramolecular chains in polymorph 1-C (monoclinic, P21/c) results in steric coupling of the transforming complex species with the peripheral flipping 3MeO group. The group acts as a supramolecular latch, locking the huge geometric distortion of complex 1 and in turn the trigonal distortion of the central FeII ion in the high-spin state, thereby keeping it from the transition to the low-spin state over a large thermal range. Analysis of the crystal packing of 1-C reveals significantly changing patterns of close intermolecular interactions on going between the phases substantiated by the energy framework analysis. The detected supramolecular mechanism leads to a record-setting robust 105 K wide hysteresis spanning the room temperature region and an atypically large TLIESST relaxation value of 104 K of the photoexcited high-spin state. This work highlights a viable pathway toward a new generation of cleverly designed molecular memory materials.

Study on the coordination of cyclopentanocucurbit[5,6]uril with Fe3+, Co2+ and Ni2+ ions.

This paper reports the coordination of cyclopentanocucurbit[5]uril (CyP5Q[5]) and cyclopentanocucurbit[6]uril (CyP6Q[6]) with Fe(ClO4)3, Co(ClO4)2 and Ni(ClO4)2. Single crystal X-ray diffraction analysis shows the metal ions are directly coordinated with the portal of the cucurbit[n]uril to form a one-dimensional supramolecular chain or independent systems in the CyP5Q[5]@Fe(ClO4)3, CyP5Q[5]@Co(ClO4)2, CyP6Q[6]@Co(ClO4)2 and CyP5Q[5]@Ni(ClO4)2 complexes. In CyP6Q[6]@Fe(ClO4)3, the metal ion is not directly coordinated with the cucurbit[n]uril portal, but after forming Fe(H2O)6, it interacts with the cucurbit[n]uril portal via a hydrogen bond. The CyP6Q[6]@Ni(ClO4)2 complex is quite special; in this system, there are both metal ions directly coordinated with the cucurbit[n]uril portal and free on the outer surface of the cucurbit[n]uril.

A study on the coordination of cyclohexanocucurbit[6]uril with copper, zinc, and magnesium ions

Abstract Herein, we report the supramolecular complexes of cyclohexanocucurbit[6]uril (CyH6Q[6]) with Cu(ClO4)2, Zn(ClO4)2, and Mg(ClO4)2 in formic acid solution. The crystal structure was determined using single crystal X-ray diffraction. The analysis results showed that CyH6Q [6] formed a one-dimensional supramolecular chain with Cu(ClO4)2 and formed a supramolecular assembly with a mixture ratio of 2:3 with Zn(ClO4)2 and Mg(ClO4)2. In this system, ClO 4 − {\text{ClO}}_{4}^{-} induced CyH6Q[6] and metal ions to form supramolecular complexes through ion–dipole interactions.

Metal-induced different structures of four cyclopentanocucurbit[5]uril-based complexes

In this paper, four supramolecular complexes were constructed by using cyclopentanocucurbit[5]uril (CyP5Q[5]) with CrCl3, CoCl2, HgCl2 and Pb(ClO4)2 respectively in 3 mol/L hydrochloric acid aqueous solution, and then Single-crystal X-ray diffraction was employed to characterize these supramolecular complexes: [C45H56Cl3CrN20O13(1), C45H60Cl8Co3N20O15(2), C45H64Cl6Hg2N22O13(3) and C90H112Cl8Pb4N40O55(4)]. Interestingly, complex 4 is completely different from the other three complexes in that the Pb2+ is coordinated with all the five carbonyl groups of the CyP5Q[5] to form a one-dimensional supramolecular chain. It is worth noting that complex 3 is different from complex 1 and complex 2 in the way of coordination in which the central Hg2+ ion is not coordinated with water molecules but with two chloride ions, and with five portal carbonyl oxygen atoms of the CyP5Q[5], while the central Co2+ or Cr3+ is only partially coordinated with portal carbonyl oxygen atoms of the CyP5Q[5].

New [2,2]Fluorenophanes Give Insights into Asymmetric Charge Transfer-Mediated Exciton Delocalization along the π-π Packing Direction.

A series of new [2,2]fluorenophanes has been synthesized and characterized; among them, molecules of crystallographically asymmetric anti-[2.2](1,4)(4,1)fluorenophane (K2C-2) aggregate to form one-dimensional supramolecular chain structures through effective intermolecular π-π overlapping. This, in combination with the synergistic intramolecular π-π interaction, leads to prominent dual emission mediated by charge transfer (CT) exciton delocalization. Support of this new insight is given by mapping the transition density along the π-π packing direction where the intramolecular excitation and intermolecular CT coexist in K2C-2.

High temperature anionic Fe(III) spin crossover behavior in a mixed-valence Fe(II)/Fe(III) complex.

Two ion-pair Fe(iii) complexes (PPh4)[FeIII(HATD)2]·2H2O (1, H3ATD = azotetrazolyl-2,7-dihydroxynaphthalene) and [FeII(phen)3][FeIII(HATD)2]2·3DMA·3.5H2O (2, phen = 1,10-phenanthroline, DMA = N,N-dimethylformamide) were synthesized by employing the tridentate ligand H3ATD. Crystal structure analyses reveal that complexes 1 and 2 consist of FeIII ions in an octahedral environment where a FeIII ion is coordinated by two HATD2- ligands forming the [FeIII(HATD)2]- core. The shortest cationanion distance between the phosphorus ion of the (PPh4)+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 13.190 Å in complex 1, whereas that between the ferrous ion of the [FeII(Phen)3]2+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 7.821 Å in complex 2. C-HC and C-HO hydrogen interactions between the [FeII(phen)3]2+ cation and the [FeIII(HATD)2]- anion are observed in 2. Face-to-face π-π stacking interactions between naphthalene rings with the separated interplanar center to center distances of 3.421-3.680 Å were observed, which result in a one-dimensional supramolecular chain in complexes 1 and 2. Magnetic measurements show that complex 1 is in the low-spin (LS) state below 500 K, whereas 2 undergoes a high temperature spin crossover (SCO) between 360 and 500 K. Magneto-structural relationship studies reveal that π-stacking, hydrogen interactions and Coulomb interactions between the [FeIII(HATD)2]- anion and the [FeII(phen)3]2+ cation play a crucial role in the high temperature Fe(iii) SCO behaviour of complex 2.

Syntheses and properties of two types of linear tetranuclear heterometallic clusters with identical formulas but different structures

Eight 3d-4f heterometallic complexes, Ln2Ni2(3,4-DCB)10(phen)2 [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Er (7) and Yb (8)], were successfully prepared through the self-assembly reactions of Ln(NO3)3·nH2O, NiCl2·6H2O, 3,4-dichlorobenzoic acid (3,4-HDCB), NaOH and 1,10-phenanthroline (phen) under solvothermal conditions. These eight complexes were characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). Complexes 1–8 have identical formulas, but different molecular structures. Complexes 1–6 and 7–8 are isostructural. In 1–8, the 3,4-DCB anions link the Ni(II) and Ln(III) ions by different coordination modes to form two types of linear tetranuclear heterometallic clusters. Adjacent tetranuclear clusters are connected by π–π interactions between 3,4-DCB and phen into a one-dimensional (1D) supramolecular chain. The photoluminescent properties of 3 and the magnetic properties of 1–2 and 4–8 were investigated.

Acidity-Driven Bidirectional Room-Temperature Spin-State Switch and Fluorescence Modulation of a Mononuclear Fe(II) Complex

Room-temperature switchable materials showing multiple responses toward external stimuli are highly desired. Herein, we report bidirectional spin-state switch and fluorescence modulation of an Fe(I...

Synthesis, structural characterization, and antibacterial activity of diorganotin complexes of Schiff base derived from 4-(diethylamino)salicylaldehyde and L-tyrosine

Four new diorganotin complexes of Schiff base derived from 4-(diethylamino)salicylaldehyde and L-tyrosine, R2Sn[2-O-4-Et2NC6H3CH=NCH(CH2C6H4OH-4)COO] (R = Me (1), Et (2), Cy (3), Ph (4)), were synthesized by the one-pot reaction of L-tyrosine, 4-(diethylamino)salicylaldehyde and diorganotin dichloride in the presence of triethylamine and characterized by means of elemental analysis, IR, 1H and 13C NMR spectra, and the X-ray single-crystal diffraction. X-Ray analyses of 1–4 revealed that the tin atoms of the complexes exhibit seriously distorted trigonal-bipyramidal geometries with a monodentate carboxylate oxygen atom and a phenolic oxygen atom occupying the axial positions. The intermolecular O─H⋅⋅⋅O hydrogen bonds and Sn⋅⋅⋅O weak interactions connected the molecules into one-dimensional supramolecular chain. Bioassay results indicated that 1–4 had moderate antibacterial activity against Escherichia coli and the fluorescence determinations show the complexes may be explored for potential luminescent materials.

Supramolecular networks and Hirshfeld surfaces of oxydiacetic acid and iminodiacetic acid salts.

Oxydiacetic acid (Oda) and iminodiacetic acid (Ida) have been combined with two diamines, namely ethylenediamine (en) and o-phenylenediamine (o-phen), to give three molecular crystals of compositions [(Oda2-)(en2+)]·H2O (Odaen), [(Ida-)(0.5en+)] (Idaen) and [(Oda-)(o-phen+)] (Odaophen). Single crystal X-ray structure determination of the three molecular salts revealed that the hydrogen bonding interactions form distinct supramolecular chains. In Odaen, water molecules and Oda2- anions generate one-dimensional supramolecular chains where two chains overlap each other in zigzag form. In Odaophen, Oda- anions generate a one-dimensional linear supramolecular chain. In Idaen, both intermolecular and intramolecular proton transfer occurs. Ida- anions generate a one-dimensional zigzag chain. These one-dimensional supramolecular chains extend to form different two-dimensional supramolecular chains by the interaction of diaminium and monoaminium cations. Intermolecular close contacts are also examined using Hirshfeld analysis to reveal similarities and differences in the crystal structures.

Electrocatalytic and Hg2+ Fluorescence Identifiable Bifunctional Sensors for a Series of Keggin Compounds.

By using a 2,2'-dimethyl-4,4'-bithiazole (dm4bt) ligand, Keggin polyanions, and different metal ions, nine Keggin-based compounds, namely, {[Ag(dm4bt)2][Ag2(dm4bt)3]}2(PW12O40)(H2PWV2WVI10O40) (1), [CuI(dm4bt)2][CuII(dm4bt)2(PW12O40)] (2), [CuI(dm4bt)2]4(SiW12O40) (3), {[Zn(dm4bt)2]2(SiW12O40)} (4), [Zn(dm4bt)2(H2O)]2(HPMoV2MoVI10O40)·2H2O (5), [Zn(dm4bt)2(Mo2O7)] (6), [Cd(dm4bt)3][Cd(dm4bt)2(H2O)(PMo12O40)]2·2H2O (7), [Cd(dm4bt)3](PMo12O40)·(Hdm4bt) (8), and [Cd(dm4bt)2(H2O)2]2(HPMoV2MoVI10O40)·2H2O (9), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectroscopy, and elemental analyses. Compounds 1-9 are zero-dimensional structures except compound 6, which exhibits a one-dimensional structure. In compound 1, there are three isolated subunits: Keggin anions, binuclear [Ag2(dm4bt)3]2+, and mononuclear [Ag(dm4bt)2]+ clusters. The binuclear [Ag2(dm4bt)3]2+ cluster has a Ag-Ag bond. In compound 2, a monosupporting anion {[CuII(dm4bt)2](PW12O40)}- and an isolated [Cu(dm4bt)2]+ cluster exist. By changing the transition metal ions, we obtained two different structures: a supramolecular 3 and a bisupporting anion in 4. By a one-pot method, we successfully obtained compounds 5 and 6, 7 and 8, respectively. In compound 5, the [Zn(dm4bt)2(H2O)]2+ subunit links adjacent PMo12 anions via S···O interactions to form a one-dimensional (1D) supramolecular chain. In compound 6, some PMo12 ions have transformed to [Mo2O7] n2 n- chains. The [Zn(dm4bt)2]2+ clusters buckle up and down the chain. Compound 7 has a monosupporting anion and an isolated [Cd(dm4bt)3]2+ cluster. Compound 8 has isolated anions and [Cd(dm4bt)3]2+ clusters. By changing the pH of 7 and 8, a distinct supramolecular compound 9 was obtained. Additionally, the optical band gap, electrochemical, and photocatalytic properties of 1-9 have been investigated in detail. The carbon paste electrodes can be used as bifunctional amperometric and fluorescence sensors for recognition of Hg2+. The n-CPEs as electrochemical sensors can show accurate selectivity for NO2- ions in some common ions. In the fluorescence sensor experiment, fluorescence intensities decrease more than 80% when quenched by Hg2+.

A one-dimensional supramolecular chain based on [H2V10O28]4− units decorated with 4-dimethylaminopyridinium ions: an experimental and theoretical characterization

One-dimensional supramolecular structure with [H2V10O28]4− units was synthesized and experimental-theoretical characterized as potential releasing prodrug of the decavanadate ion.

Solid-state supramolecular architectures formed by co-crystallization of melamine and 2-, 3- and 4-fluorophenylacetic acids

A family of supramolecular complexes of melamine with fluorophenylacetic acid isomers using solvent-assisted and evaporation-based techniques has been prepared. Crystallization of melamine with 2-fluorophenylacetic acid yield hydrated ionic supramolecular complex (1), whereas crystallization of melamine with 3- and 4-fluorophenylacetic acids leads to formation of neutral supramolecular complexes (2, 3), all with base to acid ratio of 1:2. The supramolecular assembly is driven by the noncovalent interactions, most commonly by the hydrogen bonds. The components of the crystal 1 interact via NH⋯O and OH⋯N hydrogen bonds with R22(8) and R32(10) graphs forming ionic supramolecular complex, whereas the components in the crystals 2 and 3 interact with a graph of R22(8) forming neutral supramolecular complexes. The singly protonated melamin-1-ium residues in 1 interact each other via a pair of NH⋯N hydrogen bonds forming one dimensional chains along [−110] that interact via NH⋯O with deprotonated and neutral 2-fluorophenylacetic acid units and water molecules forming ribbon. In 2 and 3 co-crystals the melamine interacts with 3- and 4-fluorophenylacetic acids via a pair of NH⋯O hydrogen bonds forming pseudo one-dimensional supramolecular chains along [010] direction. Hirshfeld surface and analysis of 2D fingerprint plots have been analysed both quantitatively and qualitatively interactions that governing the supramolecular organisation. The IR and Raman vibrational characterization of the supramolecular complexes 1–3 was supported by the spectra of their deuterated analogues.

Metal–Ligand Complexation through Redox Assembly at Surfaces Characterized by Vibrational Spectroscopy

The formation of metal–organic complexes on metal surfaces is a research topic of high interest to develop tunable functional surfaces. One such focus of this research is the formation of single site metal centers that have uniform ligand environments and thus uniform chemistry. We report the complexation of Pt and Ag with the ligand dipyridyl-tetrazine (DPTZ) on Ag(111) and of Pt with DPTZ on the reconstructed Au(100) surface. Each metal atom binds two DPTZ molecules resulting in one-dimensional supramolecular chains across the surface. Pt complexation occurs immediately after Pt deposition at room temperature on either surface. This complexation is improved with annealing to 170 °C on Au(100). DPTZ forms complexes with Ag atoms from the Ag(111) substrate when annealed to 110 °C. No similar complexation with substrate atoms is seen on Au(100). This metal–organic complexation with substrate atoms on Ag(111) takes place even when the DPTZ is already complexed to Pt, demonstrating a Pt replacement reaction ...

Synthesis, characterization, structures and Suzuki coupling reaction of Cu(II) complexes derived from N and O-containing organic ligand

Three copper complexes constructed with N and O-containing organic ligand (1-(2-pyridinylazo)-2-Naohthalenol, 8-Quinolinol, biacetyl dioxime), [(CuI)L]n (1), [Cu(I-OX)2] (2), and [Cu(dmgH)2]2 (3), have been synthesized from the reaction of copper(I) iodide with relation ligand under solvothermal or solution-diffusion conditions. The single-crystal X-ray structural analysis reveals that complex 1 crystallizes in the hexagonal system and consists of [(CuI)L]n infinite 1 D chains. The neighboring chains with different orientation and location are connected to further expand to 3 D supramolecular network structure by C-H⋯O hydrogen bonds. Complex 2 has monoclinic system and the π-π stacking interactions between the adjacent complex molecules enabled it to form one-dimensional supramolecular chain. Complex 3 crystallizes in the tetragonal system and 2 D packing forms petaloid macrocycle structure. The powder X-ray diffraction, luminescent, etc. were also studied in this paper. In addition, their catalytic characters in Suzuki C, C cross-coupling reactions were investigated. Complex 1 was a more effective catalysis than complexes 2 and 3.

Hydrogen-bonded assemblies in the molecular crystals of 2,2'-thiodiacetic acid with ethylenediamine and o-phenylenediamine.

Carboxylate molecular crystals have been of interest due to the presence of hydrogen bonding, which plays a significant role in chemical and crystal engineering, as well as in supramolecular chemistry. Acid-base adducts possess hydrogen bonds which increase the thermal and mechanical stability of the crystal. 2,2'-Thiodiacetic acid (Tda) is a versatile ligand that has been widely explored, employing its multidendate and chelating coordination abilities with many metals; however, charge-transfer complexes of thiodiacetic acid have not been reported. Two salts, namely ethylenediaminium 2,2'-thiodiacetate, C2H10N22+·C4H4O4S22-, denoted Tdaen, and 2-aminoanilinium 2-(carboxymethylsulfanyl)acetate, C6H9N2+·C4H5O4S-, denoted Tdaophen, were synthesized and characterized by IR, 1H and 13C NMR spectroscopies, and single-crystal X-ray diffraction. In these salts, Tda reacts with the aliphatic (ethylenediamine) and aromatic (o-phenylenediamine) diamines, and deprotonates them to form anions with different valencies and different supramolecular networks. In Tdaen, the divalent Tda2- anions form one-dimensional linear supramolecular chains and these are extended into a three-dimensional sandwich-type supramolecular network by interaction with the ethylenediaminium cations. However, in Tdaophen, the monovalent Tda- anions form one-dimensional zigzag supramolecular chains, which are extended into a three-dimensional supramolecular network by interaction with the 2-aminoanilinium cations. Thus, both three-dimensional structures display different ring motifs. The structures of these diamines, which are influenced by hydrogen-bonded assemblies in the molecular crystals, are discussed in detail.

Structural phase transitions and dielectric transitions in a 1,4-diazabicyclo[2.2.2]octane (dabco) based organic crystal

1,4-Diazabicyclo[2.2.2]octane (dabco) based organic crystal [(Hdabco)(H2O)](PF6) (1) was synthesized and characterized. Its structure is featured by wavy-like one-dimensional supramolecular hydrogen bond chains built from the [(Hdabco)(H2O)] units from end to end. Compound 1 undergoes two reversible phase transitions at 226/268 K and 178/181 K, respectively. The disorder-order transition of water molecule in the hydrogen bond chain induces the phase transition at 226 K while the twisting of the [Hdabco]+ cation and displacements of the PF6− anion and H2O molecules trigger the phase transition at 178 K. Dielectric transitions are thus triggered in the crystal.

Supramolecular solid-state architectures formed by co-crystallization of melamine and 2-, 3- and 4-chlorophenylacetic acids

A family of supramolecular complexes of melamine with chlorophenylacetic acid isomers using solvent-assisted and evaporation-based techniques has been prepared. Crystallization of melamine with 2-chlorophenylacetic acid yield hydrated ionic supramolecular complex (1), whereas crystallization of melamine with 3- and 4-chlorophenylacetic acids leads to formation of neutral supramolecular complexes (2, 3), all with base to acid ratio of 1:2. Within chlorophenylacetic acid isomers only in 2-chlorophenylacetic acid isomer as the stronger acid the proton transfer to melamine takes place. The crystal structures of supramolecular complexes have been determined. The supramolecular assembly is driven by the noncovalent interactions, most commonly by the hydrogen bonds. The components of the crystals interact via NH⋯O and OH⋯N with a graph of R22(8) forming respective ionic or neutral supramolecular complexes. All three supramolecular complexes studied interact each other via a pair of NH⋯O hydrogen bonds forming pseudo one-dimensional supramolecular chains along [1–10] and [−110] in 1 and along [010] in 2 and 3. Hirshfeld surface and analysis of 2D fingerprint plots have been analysed both quantitatively and qualitatively interactions governing the supramolecular organisation. The IR and Raman vibrational characterization of the supramolecular complexes 1–3 was supported by the spectra of their deuterated analogues.