High-dimensional Supramolecular Networks Research Articles

MnIII-FeIII Heterometallic Compounds within Hydrogen-Bonded Supramolecular Networks Promoted by an [Fe(CN)5(CNH)]2- Building Block: Structural and Magnetic Properties.

The reaction of [Fe(CN)6]3- and [Mn(acacen)]+ (H2acacen = N, N'-bis(acetylacetone)ethylenediamine) building units in the presence of supramolecular cations, [(F-Anil)(18-crown-6)]+ (F-Anil+ = 3-fluoroanilinium) or [(Me-F-Anil)(18-crown-6)]+ (Me-F-Anil+ = 3-fluoro-4-methylanilinium), affords two new bimetallic compounds, [(F-Anil)(18-crown-6)][Mn(acacen)Fe(CN)5(CNH)]·MeOH (1) and [(Me-F-Anil)(18-crown-6)][Mn(acacen)(MeOH)Fe(CN)5(CNH)]·MeOH (2), respectively. Compound 1 exhibits a one-dimensional topology, while compound 2 is a dinuclear discrete system due to the coordination of a MeOH molecule at the axial position of the [Mn(acacen)]- unit. For both systems, the acidity of the corresponding supramolecular cation triggers the protonation of the FeIII moiety as [Fe(CN)5(CNH)]2-. Moreover, the resulting -CNH ligand induces hydrogen bonding interactions connecting the chains for 1 or the molecules for 2 into higher dimensional supramolecular networks. Magnetic properties of compounds incorporating these [Fe(CN)5(CNH)]2- building blocks were, for the first time, thoroughly investigated, indicating a three-dimensional antiferromagnetic order of single-chain magnets for 1 and an antiferromagnetically interacting S = 3/2 spin ground state for 2.

A new copper(II) supramolecular coordination polymer and a dinuclear compound with multifunctional 2-amino-5-sulfobenzoic acid and flexible N-donor ligands: synthesis, structure and characterization.

Multifunctional 2-amino-5-sulfobenzoic acid (H2afsb) can exhibit a variety of roles during the construction of supramolecular coordination polymers. The pendant carboxylic acid, sulfonic acid and amino groups could not only play a role in directing bonding but could also have the potential to act as hydrogen-bond donors and acceptors, resulting in extended high-dimensional supramolecular networks. Two new CuII coordination compounds, namely catena-poly[[[diaquacopper(II)]-μ-1,6-bis(1H-1,2,4-triazol-1-yl)hexane-κ2N4:N4'] bis(3-amino-4-carboxybenzenesulfonate) dihydrate], {[Cu(C10H16N6)2(H2O)2](C7H6NO5S)2·2H2O}n or {[Cu(bth)2(H2O)2](Hafsb)2·2H2O}n, (1), and bis(μ-2-amino-5-sulfonatobenzoato-κ2O1:O1')bis{μ-1,2-bis[(1H-imidazol-1-yl)methyl]benzene-κ2N3:N3'}bis[aquacopper(II)] trihydrate, [Cu2(C7H5NO5S)2(C14H14N4)2(H2O)2]·3H2O or [Cu2(afsb)2(obix)2(H2O)2]·3H2O, (2), have been obtained through the assembly between H2afsb and the CuII ion in the presence of the flexible N-donor ligands 1,6-bis(1H-1,2,4-triazol-1-yl)hexane (bth) and 1,2-bis[(1H-1,2,4-triazol-1-yl)methyl]benzene (obix), respectively. Compound (1) consists of a cationic coordination polymeric chain and 3-amino-4-carboxybenzenesulfonate (Hafsb-) anions. Compound (2) exhibits an asymmetric dinuclear structure. There are hydrogen-bonded networks within the lattices of (1) and (2). Interestingly, both (1) and (2) exhibit reversible dehydration-rehydration behaviour.

Three New Hg(II) Complexes Constructed From Mercapto- and Amino-Containing Triazole Ligands: Syntheses, Crystal Structures, and Luminescent Properties

Three new mercury(II) complexes [HgI2(3-aptt)2] (1), [Hg(4-aptt)2] (2), and [Hg(a-mtt)2]·H2O (3) were synthesized based on three structurally related ligands: 4-amino-3-(3-pyridyl)-1H-1,2,4-triazole-5-thione (3-Haptt), 4-amino-3-(4-pyridyl)-5-mercapto-1,2,4-triazole (4-Haptt), and 4-amino-3-methyl-1,2,4-triazoline-5-thiadone (a-Hmtt). The structures of complexes 1–3 were determined by single-crystal X-ray diffraction techniques and further characterized by elemental analyses and IR spectra. The results reveal that these three complexes take mononuclear structures. And although various weak interactions, including N‒H···I and N···H‒O H-bondings as well as Ntrz···Npy and π···π stacking, play significant roles in crystal structures, just these weak interactions link the mononuclear units into higher dimensional supramolecular networks. Their thermal stabilities and the solid state luminescent properties have also been discussed.

Syntheses, structures, and luminescence of three metal carboxylate polymers of 2,5-dibenzoylterephthalic acid and N-donor auxiliary ligands

Three coordination polymers, [CdL(2,2′-bpy)] (1), [ZnL(phen)2] (2), and [ZnL(2,2′-bpy)] (3) (H2L = 2,5-dibenzoylterephthalic acid, 2,2′-bpy = 2,2′-bipyridine, and phen = 1,10-phenanthroline), were synthesized and crystallographically characterized. The compounds were further characterized by elemental analyses, FTIR, thermogravimetric analyses, and powder X-ray diffraction. Complex 1 exhibits a 2D sheet structure with (4,4) grid units, while 2 and 3 present infinite 1D zig–zag chain structures. The complexes are all extended into high-dimensional supramolecular networks through intermolecular hydrogen bonds and π–π stacking interactions. A structural comparison of 1–3 demonstrates that the characteristics of subsidiary ligands and slight difference in coordination models of L play a very important role in construction of the complexes. Additionally, luminescence of the complexes is also investigated at room temperature.

Syntheses, crystal structures and magnetic properties of four cyano-bridged bimetallic alternating chain complexes based on [CrIII(salen)(CN)2]− and [CrIII(bipy)(CN)4]− building blocks

Four cyano-bridged bimetallic alternating chain complexes, [Mn(salen)]3[Cr(salen)(CN)2]3·4H2O (1) (salen = N,N′-ethylenebis(salicylideneiminato)dianion), [Mn(salpn)]3[Cr(salen)(CN)2]3·4H2O (2) (salpn = N,N′-1,2-propylenebis(salicylideneiminato)dianion), [Mn(salen)][Cr(bipy)(CN)4] (3) and [Mn(salpn)][Cr(bipy)(CN)4] (4), have been synthesized and characterized. The single crystal X-ray analysis reveals the 1-D alternating chain structure for all the four complexes. Noteworthily, complexes 1 and 2 exhibit crystallographic disordering of the MnIII and CrIII, as well as the bridged C and N atoms from cyano groups, due to the difficulty in identifying these atoms using the X-ray diffraction technique. All the four assemblies show significant interchain π–π interactions and thus, further extend to high dimensional supramolecular networks. The magnetic measurement reveals the expected dominant intrachain antiferromagnetic interactions in complexes 1–4. However, the weak intrachain antiparallely aligned spins seem to be overcome by external fields, which lead to the higher magnetization values than expected.

Construction of three high-dimensional supramolecular networks from temperature-driven conformational isomers

Under different temperatures, the reaction mixture of the multidentate organic ligand usy-L4 and Zn(NO3)2 + NaN3 crystallized to give three conformational isomers, namely Zn(usy-L4)(η1-N3)2 (α-1, β-2 and γ-3) (usy-L4 = N,N-dimethyl-2-(pyridin-2-ylmethylimino)ethanamine). Single-crystal X-ray diffraction analyses reveal that the conformational isomerism of three compounds 1–3 stems from the different orientations of two azide groups with η1-terminal nitrogen atom coordinating to central zinc ion in reference to the basal chelating plane of ligand usy-L4, and further resulting in different supramolecular networks with two-dimensional 44 rhombic-grid for α-1, a three-dimensional 36·418·53·6 compressed-NbO framework for β-2, and a three-dimensional “dense” 424·64 topology for γ-3. Meanwhile, three isomers may be also irreversibly converted from 1 to 2, to 3 through SC-to-SC transformation driven by temperature.

Synthesis, structure and photophysical properties of two transitional metal supramolecular complexes

Two supramolecular complexes: [Co(2,6-PDC)(Hdmpz) 3]·H 2O ( 1) and [Zn(2,6-PDC)(Hdmpz) 2] ( 2) {2,6-PDC = pyridine-2,6-dicarboxylic acid, Hdmpz = 3,5-dimethylpyrazol}, self-assembles via O–H⋯O and N–H⋯O hydrogen bondings into supramolecular networks, which are characterized by elemental analyses, IR spectra and single crystal X-ray diffraction analysis. Both of them consist of two-dimensional networks that are stacked together by typical hydrogen bonding interactions (i.e. O–H⋯O and N–H⋯O), which often play important roles in the formation of low-dimensional into high-dimensional supramolecular networks. In addition, quantum chemistry calculations and surface photovoltage spectroscopy are performed firstly with the complexes.

Regulation and Properties of Diversiform Cd(II) Supramolecular Complexes with a Bulky Naphthalene-Based Dicarboxyl Tecton and Different N-Donor Co-Ligands

A series of six CdII coordination complexes have been prepared by using naphthalene-2,3-dicarboxylic acid (H2ndc), an analogue of 1,2-benzenedicarboxylic acid (H2bdc), and different N-donor auxiliary co-ligands (chelating or bridging), namely, [Cd(ndc)]∞ (1), {[Cd2(ndc)2(2bpy)2(H2O)2](CH3OH)0.5}2 (2), [Cd2(ndc)2(phen)2]∞ (3), {[Cd(ndc)(4bpy)0.5(H2O)2](H2O)}∞ (4), {[Cd(ndc)(abp)(H2O)](H2O)}∞ (5), and {[Cd(ndc)(bpp)2](H2O)3}∞ (6) (ndc = naphthalene-2,3-dicarboxylate, 2bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, 4bpy = 4,4′-bipyridine, abp = trans-4,4′-azobis(pyridine), and bpp = 1,3-bis(4-pyridyl) propane). The initial complex 1 shows a two-dimensional (2-D) (44.62) coordination network. 2 and 3 possess tetranuclear and one-dimensional (1-D) structures due to the incorporation of auxiliary chelating co-ligands 2bpy and phen, respectively, which are further interlinked via secondary interactions such as hydrogen bonding and aromatic stacking to result in higher-dimensional supramolecular networks. Whe...

Zinc(II) and mercury(II) coordination architectures with two pyridyl/benzimidazol-1-yl-based ligands: Crystal structures and photoluminescent properties

In our efforts to investigate the relationships between the structures of ligands and their complexes, two structurally related ligands, 1-(2-pyridylmethyl)-1 H-benzimidazole ( L 1 ) and 1-(4-pyridylmethyl)-1 H-benzimidazole ( L 2 ), and their four complexes, [Zn( L 1 ) 2Cl 2] ( 1), [Hg( L 1 )Br 2] ∞ ( 2), {[Zn( L 2 )Cl 2](CH 3CN)} ∞ ( 3) and [Hg( L 2 )Br 2] 2(CH 3CN) 2 ( 4) were synthesized and structurally characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction analysis. Structural analyses show that 1 has a mononuclear structure, and 2 and 3 both take 1D structure. While 4 takes a dinuclear structure. 1, 2 and 4 were further linked into higher-dimensional supramolecular networks by weak interactions, such as C–H⋯Cl and C–H⋯Br H-bonding, C–H⋯π, and π⋯π stacking interactions. The structural differences of 1– 4 may be attributed to the difference of the spatial positions of the terminal N donor atoms in the pendant pyridyl groups in L 1 and L 2 , in which the pyridine rings may act as the directing group for coordination and the benzimidazole rings act as the directing group for π⋯π stacking and C–H⋯π interactions. The luminescent properties of the corresponding complexes and ligands have been further investigated.

Hydrothermal syntheses and structures of two novel polyoxometalate-based 3-D supramolecular architectures

Two supramolecular architectures based on polyoxometalates: [4,4′-Hbpy] 2[Ni(4,4′-bpy) 2(H 2O) 4][AsW VI 11W VO 40]·4H 2O ( 1) and [4,4′-H 2bpy] 2[PMo VI 9Mo V 3O 40]·2H 3O ( 2) (4,4′-bpy = 4,4′-bipyridine) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR spectra, XPS spectra and single crystal X-ray diffraction analyses. The two compounds consist of 4,4′-bpy units with different polyoxometalates, α-Keggin [AsW VI 11W VO 40] 4− and pseudo-Keggin [PMo VI 9Mo V 3O 40] 6−, respectively. No direct interactions occur among polyoxoanions in these two compounds, but the clusters together with metal-organic units or organic 4,4′-bpy units and/or water molecules construct the high-dimensional supramolecular networks through hydrogen bonds. The crystal structure analyses reveal that the organic 4,4′-bpy units have a major influence on the packing arrangements of crystals.

Two new Cu(II) complexes with 3-(2-pyridyl)pyrazol-based ligands: Synthesis, crystal structures, and magnetic properties

In our efforts to investigate the relationships between the structures of ligands and their complexes, two structurally related 3-(2-pyridyl)pyrazole-based ligands, 1-[3-(2-pyridyl)pyrazol-1-ylmethyl]benzene ( L 1) and 3-[3-(2-pyridyl)pyrazol-1-ylmethyl]pyridine ( L 2), and their two Cu(II) complexes, [Cu( L 1) 2(NO 3)](NO 3)(CH 3CH 2OH) ( 1) and [Cu 2( L 2) 2(Cl) 4] ( 2), were synthesized and structurally characterized by elemental analyses, IR spectra and single crystal X-ray diffraction analysis. Complex 1 has a mononuclear structure, while 2 takes the dinuclear structure, which were further linked into higher-dimensional supramolecular networks by intra- or inter-molecular weak interactions, such as C–H⋯O hydrogen-bonding, C–H⋯π, and π⋯π stacking interactions. The structural differences of 1 and 2 can be attributed to the difference of counter anions and the different pendant aromatic groups of L 1 and L 2, in which the benzene and pyridine rings act as the directing group for π⋯π stacking and C–H⋯π interactions. Moreover, magnetic properties of 2 have been further investigated in detail.

Mn(II) coordination architectures with mixed ligands of 3-(2-pyridyl)pyrazole and carboxylic acids bearing different secondary coordination donors and pendant skeletons

In our efforts to investigate the factors that affect the formation of coordination architectures, such as secondary coordination donors and pendant skeletons of the carboxylic acid ligands, as well as H-bonding and other weak interactions, two kinds of ligands: (a) 3-(2-pyridyl)pyrazole ( L 1 ) with a non-coordinated N atom as a H-bonding donor, a 2,2′-bipyridyl-like chelating ligand, and (b) four carboxylic ligands with different secondary coordination donors and/or pendant skeletons, 1,4-benzenedicarboxylic acid (H 2 L 2 ), 4-sulfobenzoic acid (H 2 L 3 ), quinoline-4-carboxylic acid (H L 4 ) and fumaric acid (H 2 L 5 ), have been selected to react with Mn(II) salts, and five new complexes, [Mn( L 1 ) 2(SO 4)] 2 ( 1), [Mn( L 1 ) 2( L 2 )] ∞ ( 2), [Mn( L 1 )(H L 3 ) 2] ∞ ( 3), Mn( L 1 ) 2( L 4 ) 2 ( 4), and [Mn( L 1 ) 2( L 5 )] ∞ ( 5), have been obtained and structurally characterized. The structural differences of 1– 5 can be attributed to the introduction of the different carboxylic acid ligands (H 2 L 2 , H 2 L 3 , H L 4 , and H 2 L 5 ) with different secondary coordination donors and pendant skeletons, respectively. This result also reveals that the typical H-bonding (i.e. N–H⋯O and O–H⋯O) and some other intra- or inter-molecular weak interactions, such as C–H⋯O weak H-bonding and π⋯π interactions, often play important roles in the formation of supramolecular aggregates, especially in the aspect of linking the multi-nuclear discrete subunits or low-dimensional entities into high-dimensional supramolecular networks.

Polymeric silver(I) complexes with pyridyl dithioether ligands: experimental and theoretical investigations on the coordination properties of the ligands.

The reactions of four flexible tetradentate ligands, 1,3-bis(2-pyridylthio)propane (L1), 1,4-bis(2-pyridylthio)butane (L2), 1,5-bis(2-pyridylthio)pentane (L3) and 1,6-bis(2-pyridylthio)hexane (L4) with AgX (X = BF4-, ClO4-, PF6-, or CF3SO3-) lead to the formation of seven new complexes: [AgL1(BF4)]2 (1), [[AgL2](ClO4)]infinity (2), [[AgL2(CH3CN)](PF6)]infinity (3), [[AgL3](BF4)(CHCl3)]2 (4), [[AgL3(CF3SO3)](CH3OH)(0.5)]infinity (5), [[Ag2L4(2)](BF4)2]infinity (6), and [[AgL4](PF6)]infinity (7), which have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that complexes 1 and 4 possess dinuclear macrometallacyclic structures, and complexes 2, 3 and 5-7 take chain structures. In all the complexes, the nitrogen atoms of ligands preferentially coordinate to silver atoms to form normal coordination bonds, while the sulfur atoms only show weak interactions with silver atoms and the intermolecular AgS weak contacts connect the low-dimensional complexes into high-dimensional supramolecular networks. Additional weak interactions, such as pi-pi stacking, F...F weak interactions, Ag...O contacts or C-H...O hydrogen bonds, also help to stabilize the crystal structures. It was found that the parity of the -(CH2)n- spacers (n = 3-6) affect the orientation of the two terminal pyridyl rings, thereby significantly influence the framework formations of these complexes. The coordination features of ligands and their conformation changes between free and coordination states have been investigated by DFT calculations.