(C₄N₂H₁₂)₃[Ln₃(OH)(SO₄)₇] (Ln = Sm, Eu, and Tb): A Series of Honeycomb-like Open-Framework Lanthanide Sulfates with Extra-Large Channels Containing 24-Membered Rings

Three novel organic amine templated honeycomb-like lanthanide sulfates, (C₄N₂H₁₂)₃­[Ln₃­(OH)­(SO₄)₇] (Ln = Sm (<b>1</b>), Eu (<b>2</b>), and Tb (<b>3</b>)), with extra-large channels containing 24-membered rings (24MR) have been synthesized by using chair form piperazine as the structure-directing agent under one-pot solvothermal reactions. The three compounds are isostructural, and the open framework of the title compounds is the first lanthanide sulfate example with extra-large channels containing 24MR. It has an <i><b>acs</b></i> framework topology. The three compounds are strong luminescent materials that display characteristic Sm³⁺, Eu³⁺, and Tb³⁺ emission bands in the visible region. The observed second-harmonic generation efficiencies of the three compounds are all 0.4 times that of urea. TGA profiles and XRD measurements demonstrate their high thermal stability

l- and d‑[Ln(HCO₂)(SO₄)(H₂O)]_<i>n</i> (Ln = La, Ce, Pr, Nd, and Eu): Chiral Enantiomerically 3D Architectures Constructed by Double −[Ln–O]_<i>n</i>– Helices

A total of 10 three-dimensional chiral coordination compounds l- and d-[Ln­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> (Ln = La, Ce, Pr, Nd, and Eu) have been synthesized without any chiral auxiliary and characterized by IR, thermogravimetric, and elemental analyses. Their structures were determined by single-crystal X-ray structural analysis, which shows that l-[Ln­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> (Ln = La, Ce, Pr, Nd, and Eu) crystallize in space group <i>P</i>4₃ and are laevogyrate and isostructural. The chiral frameworks of l-[Ln­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> are constructed from l-helical Ln–O cluster chains, while adjacent l-type helical −[Ln–O]_<i>n</i>– chains are connected through O–Ln–O linkages to form chiral intertwined Ln–O double helices of left-handedness. d-[Ln­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> crystallize in space group <i>P</i>4₁, and their chiral frameworks consist of d-helical Ln–O cluster chains. The observed second-harmonic-generation efficiencies of [La­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i>, Ce­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i>, [Pr­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i>, [Nd­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i>, and [Eu­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> are 0.7, 0.8, 0.7, 0.5, and 0.7 times that of urea, respectively. It is particularly interesting that [Pr­(HCO₂)­(SO₄)­(H₂O)]_<i>n</i> shows good two-photon absorption

Highly Water Stable Lanthanide Metal–Organic Frameworks Constructed from 2,2′-Disulfonyl-4,4′-biphenyldicarboxylic Acid: Syntheses, Structures, and Properties

A series of three-dimensional (3D) lanthanide metal–organic frameworks (LnMOFs), (Me₂NH₂)­[LnL­(H₂O)] (Ln = Eu (<b>1</b>), Gd (<b>2</b>), Tb (<b>3</b>), Dy (<b>4</b>); H₄L = 2,2′-disulfonyl-4,4′-biphenyldicarboxylic acid) have been successfully synthesized from H₄L and Ln­(NO₃)₃·6H₂O under solvothermal conditions. Single crystal X-ray diffraction (SCXRD) shows that all LnMOFs <b>1</b>–<b>4</b> are isomorphous and isostructural with a hepta-coordinated Ln­(III) being connected through the carboxylate groups of the L^4– ligands, resulting in the formation of an one-dimensional (1D) inorganic rod-like [Ln­(−COO)₂)]⁺_<i>n</i> chain along the <i>c</i> axis. The infinite 1D chains are further linked by the sulfonate and biphenyl groups, leading to formation of a uninodal 5-connected 3D network with <b>bnn</b> topology. The present LnMOFs are the first example of anionic 3D <b>bnn</b>-net constructed on Ln–O–C rods with channels being filled with (Me₂NH₂)⁺ cations. The L^4– ligand shows a pentadentate coordination mode with two bound sulfonate groups. All the LnMOFs are insoluble in water and highly stable against moisture. Cation-exchange with Li⁺, Na⁺, and K⁺ ions can be easily performed at room temperature (RT). In addition, LnMOFs <b>1</b> and <b>3</b> display characteristic photoluminescence of Eu­(III) and Tb­(III) ions upon excitation at 394 and 353 nm, respectively. The investigation of magnetism demonstrates relatively weak antiferromagnetic interactions between Gd­(III) ions (<i>J</i> = −0.0042(5) cm^–1) in <b>2</b>, and between Dy­(III) ions (θ = −0.20(2) K) in <b>4</b>. The proton conductivity of <b>1</b> is 4.14 × 10^–8 S cm^–1 at 95% relative humidity (RH) and 25 °C

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Synthesis and Study of Three Novel Macrocyclic Selena[<i>n</i>]ferrocenophanes Containing a Naphthalene Unit

Three novel macrocyclic ligands, <b>L1–L3</b>, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1′-bis­(3-bromopropylseleno)­ferrocene. Reaction of <b>L</b> with [M­(NCMe)₄]­(PF₆)₂ (M = Pd and Pt) led to complexes [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual <i>c</i>,<i>c</i>,<i>c</i> conformation due to intramolecular C–H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [M<b>L</b>]­(PF₆)₂ (M = Pd and Pt) the half-wave potential of the 1,1′-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO–LUMO band gaps. Results were compared and correlated with the differences in molecular structures

Highly Controllable Ring–Chain Equilibrium in Quadruply Hydrogen Bonded Supramolecular Polymers

Electron-rich dioxynaphthalene (DNP) group bridged bifunctional ureidopyrimidinone (UPy) derivatives (<b>L1</b>, <b>L2</b>, and <b>L3</b>) were synthesized, which could form small cyclic monomers, oligomers, or linear supramolecular polymers at certain concentration in solution, to achieve a highly controllable ring–chain equilibrium self-assembling supramolecular system. The ring–chain equilibrium of these supramolecular monomers constructed by different lengths of oligo­(ethylene oxide) (oligoEO) chain as spacers were investigated by a combination of techniques, such as ¹H NMR, DOSY, single-crystal X-ray diffraction, and viscometry. The experiment results demonstrated that there exists intramolecular π–π stacking interaction between DNP group and intramolecularly dimerized UPy motif in the monomeric cyclic form of these supramolecular monomers, and the strength of this π–π stacking interaction directly depends on the length of the oligoEO chain. Furthermore, strong intramolecular π–π stacking interaction was found to promote self-assembly favorable for intramolecularly cyclic monomerization, leading to a great increase of critical polymerization concentration (CPC). Monomer <b>L1a</b> with the shortest length of oligoEO chain is present as an exclusive type of intramolecularly hydrogen-bonded assembly, namely the cyclic monomers, over a broad concentration range (1.6–500 mM) in solution. Single crystal structure of the cyclic monomer <b>L1b</b>, which is an analogue of <b>L1a</b>, was thoroughly studied. The CPC values of monomer <b>L2</b> and <b>L3</b> with longer oligoEO chain are ca. 70 and 23 mM, respectively. However, <b>L2</b> and <b>L3</b> could perform selective cyclization over the entire concentration range in solution after threading into the tetracationic cyclobis­(paraquat-<i>p</i>-phenylene)­cyclophane (CBPQT⁴⁺) driven by host–guest interaction, which provides another supramolecular strategy to control ring–chain equilibrium. The combined results may provide new insights into the ring–chain equilibrium and offer valuable information on the understanding of the correlation between supramolecular assistance and polymerizability