A new (4,8)-connected topological MOF as potential drug delivery

A new compound of (NH₂(CH₃)₂[Zn₃(L)₂·3.5DMF]) (1) (H₄L = 1,1′,4′,1″,4″,1‴-quaterphenyl-3,5,3‴,5‴-tetracarboxylic acid 1,3,5-benzenetrisbenzoate) was synthesized and characterized. The coordination polymer shows an unusual 4,8-connected 3D net with (4⁶)₂(4¹²·6¹²·8⁴) topology. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 22.5 wt.% per gram of dehydrated 1. 5-Fu is released in a highly controlled and progressive fashion with 92% of the drug released after 120 h. The result from this work provides a new avenue for MOF to be used as potential drug delivery.     

Synthesis,antiapoptotic biological activity and structure of an oxo–vanadium(IV) complex with an OOO ligand donor set

The oxo–vanadium(IV) complex VO(oda)(H₂O)₂ (1) (oda=oxydiacetate, O(CH₂COO⁻)₂) was obtained by reaction of aerobic aqueous solutions of VO(acac)₂ with oxydiacetic acid, O(CH₂COOH)₂. The antiapoptotic biological activity of 1 was studied in insulin-producing cells. Chemically generated nitric oxide (NO) triggers apoptotic events, such as the appearance of oligonucleosomes in cytosol, and this response was prevented by the presence of 1 in the culture medium. The molecular structure of 1 has been determined by X-ray diffraction analysis.     

Synthesis and cytotoxicity of a ruthenium nitrosyl nitric oxide donor with isonicotinic acid and a cell penetrating peptide

The syntheses and properties of trans-[Ru(NH₃)₄(L)(NO)](BF₄)₃ (L = isonicotinic acid (inaH) (I) or ina-Tat48–60 (II)) are described. Tat48–60, a cell penetrating peptide fragment of the Tat regulatory protein of the HIV virus, was linked to the ruthenium nitrosyl through inaH. I and II release NO after reduction forming trans-[Ru(NH₃)₄(L)(H₂O)]^3 +. The IC₅₀ values against B16-F10 melanoma cells of I and II (21 μmol L^− 1 and 23 μmol L^− 1, respectively) are close to that of the commercially available cisplatin (33 μmol L^− 1) and smaller than similar complexes. The cytotoxicity is assigned to the NO released from I and II.     

Synthesis and characterization of potential NO donors: novel iron–sulfur nitrosyls containing the μ-N–C–S skeleton

Binuclear paramagnetic nitrosyl iron complexes of “g∼2.03 family” were first synthesized. Their structure and properties differ from those of “the red Roussin salt ethers”. The novel nitrosyl iron complexes: [Fe₂(μ₂-SR)₂(NO)₄]·nH₂O (η¹-S, η¹-N), n=1–2, R – 3-amino-1,2,4-triazolyl (1), 1,2,4-triazolyl (2), 1-methyl-tetrazolyl (3), benzothiazolyl (4) were obtained by the exchange reaction of Na₂Fe₂(S₂O₃)₂(NO)₄ with heterocyclic thiols and studied by methods of EPR, IR and Mössbauer spectroscopy. The molecular structure of complex 1 was determined by X-ray analysis.     

Organic–inorganic hybrid supramolecular assembly through the highest connectivity of a Wells–Dawson molybdoarsenate

An unusual supramolecular hybrid material based on the Dawson molybdoarsenate, (H₂bimyb)₃(As₂Mo₁₈O₆₂) (1) (bimyb = 1,4-Bis(imidazol-l-ylmethyl) benze) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, UV, XRD, and single-crystal X-ray diffraction. In compound 1, the {As₂Mo₁₈O₆₂} cluster uses its surface oxygen atoms to attract 14 bimyb ligands, which are further surrounded by 22 Dawson polyanions via strong supramolecular interactions to form close-packed 3D supramolecular networks with a (14⁹¹)(5¹⁰)(4⁶) topology structure. Compound 1 represents the highest connectivity of Dawson molybdoarsenate. In addition, compound 1 exhibits bifunctional electrocatalytic behaviors for oxidation of ascorbic acid (AA) and reduction of hydrogen peroxide (H₂O₂), as well as high-efficient degradation ability for typical dye MB under UV light.     

A inorganic-organic hybrid material constructed from the monolacunary polyoxomolybdates and multi-nuclear copper clusters

A novel polyoxometalate (POM)-based inorganic-organic hybrid material constructed from the monolacunary Keggin-type polyoxomolybdates and the multi-nuclear copper clusters, namely, {[Cu₈(tz)₈(Htz)₄(H₂O)₅][PMo₁₀^VIMo^VO₃₉]}∙~10H₂O (1) (Htz = 1H-tetrazole) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectra, PXRD analysis. In 1, the six-nuclear copper clusters in the roof shape were bridged by the tz ligands. These clusters are extended into the wave-like layers by the μ₂-Htz ligands and the copper atoms in octahedron coordination geometry. The polyoxomolybdate anions act as the eight-connected node to link the layers into a 3D framework. In addition, the magnetic and photocatalytic properties of compound 1 have been investigated.     

Design and synthesis of two macrocyclic dinuclear coordination polymers with binding of nitric oxide

Two new coordination polymers of Robson-type macrocycles, {[CuL¹]_n (1) and {[CuL²]_n (2), were obtained by the condensation between bapa and N,N′-bis(3-formyl-5-R-salicylimine)-1,2-propylenediimine in the presence of Cu(II). These polymers have the common feature that the 3-methylaminopyridine group in one ligand coordinates to the metal ion in the neighboring coordination unit, leading to the formation of one-dimensional infinite chain. The formation of NO complexes has been confirmed by UV/Vis spectrophotometry. The binding constants were calculated to be 8.18 × 10² M^− 1, 1.2 × 10³ M^− 1 for 1 and 2, respectively. The control experiments revealed there was non-reversible binding of NO, which can be ascribed to specially coordination environment of the central Cu(II) ions. Moreover, the interactions of the complexes with calf thymus DNA (CT-DNA) have been measured by agarose gel electrophoresis, and the results showed that they can not cleavage the CT-DNA. These two complexes can be served as potential NO scavengers.Graphical abstractTwo new coordination polymers of Robson-type macrocycles, {[CuL¹]_n (1) and {[CuL²]_n (2), were obtained by the condensation between bapa and N,N′-bis(3-formyl-5-R-salicylimine)-1,2-propylenediimine in the presence of Cu(II). The NO absorption experiments revealed a moderate binding to NO and control experiments showed the non-reversibility of the binding NO to these two macrocyclic metal Cu(II) complexes.     

Photoinduced linkage isomerism of binuclear bis(pyrazole-3,5-dicarboxylato)-bridged {RuNO} centres

The two novel binuclear pyrazole-3,5-dicarboxylato-bridged {RuNO}⁶ complexes K₂[{Ru(NO)Cl}₂(μ-pzdc)₂] (1) and [{Ru(NO)(H₂O)}₂(μ-pzdc)₂]·4H₂O (2) (pzdc = pyrazole-3,5-dicarboxylate) were synthesized and characterized by elemental analysis, mass spectrometry and spectroscopic methods (NMR, UV–vis, IR). 2 was investigated by means of single-crystal X-ray diffraction analysis. On irradiation, in both 1 and 2 the existence of photoinduced long-lived metastable isonitrosyl states SI were detected by low-temperature infrared spectroscopy.     

Inorganic-organic hybrid supramolecular material based on the highest connection of a Keggin arsenotungstate with electro-/photo-catalytic properties

An extraordinary supramolecular hybrid material based on the Keggin arsenotungstate, (Hbimb)₃[AsW₁₂O₄₀]·H₂O (1) (bimb = 1,4-bis(imidazol-l-yl)butane) has been synthesized under hydrothermal condition and characterized by elemental analysis, infrared (IR), thermogravimetry (TG), X-Ray Diffractomer (XRD), and single-crystal XRD. In compound 1 the {AsW₁₂O₄₀} cluster is linked to 14 organic ligands through their surface oxygen atoms, which are further embraced by 20 polyanions analogs to form a tightly packed 3D supramolecular network with a (4⁵·6)(4⁵²·6³⁸·8)(4⁹·6)₂ topology via strong hydrogen bonds and supramolecular interactions. Compound 1 represents the highest connectivity of Keggin supramolecular arsenotungstate, which exhibits electrocatalytic behaviors for reduction of H₂O₂ and high efficiency degradation capability for two typical dyes methylene blue (MB) and rhodamine B (RhB) under UV light.     

A novel Keggin-type molybdophosphate-based helix metal-organic chain and its polypyrrole composite: Synthesis,structure and properties

A novel Keggin-type molybdophosphate-based hybrid containing left- and right-handed helical chains, {Ag[H₂(3-bptzh)](PMo₁₂O₄₀)}·H₂O (1) [3-bptzh = 1,6-bis(5-(3-pyridyl)-tetrazolyl)hexane], has been synthesized under hydrothermal condition, and characterized by IR spectra, elemental analyses, single crystal X-ray diffraction and powder X-ray diffraction. The helix metal-organic chain [AgH₂(3-bptzh)]_n^3 + is constructed from the flexible 3-bptzh ligands and Ag atoms, on which [PMo₁₂O₄₀]^3 − polyoxoanions are hanged via AgO bonds. The structural feature is fascinating and scarcely reported in POM-based complexes. The electrochemical, fluorescent and photocatalytic properties of the title compounds have been investigated. Additionally, the polypyrrole (PPy) composite material of 1 (PPy/1) has been prepared by loading polypyrrole on the surface of compound 1, which shows excellent photocatalytic activities for degradation of organic dyes under visible light irradiation.     

Organic template-directed indium phosphite-oxalate hybrid material: Synthesis and characterization of a novel 3D |C6H14N2|[In2(HPO3)3(C2O4)] compound with intersecting channels

A novel anionic three-dimensional indium phosphite-oxalate hybrid material, formulated as |C₆H₁₄N₂|[In₂(HPO₃)₃(C₂O₄)] (1) was prepared under hydrothermal conditions by using 1,4-diazabicyclo[2.2.2]octane (dabco) as a structure directing agent (SDA). Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the orthorhombic system space group Pna2₁ (No. 33) having unit cell parameters a = 12.4143(13) Å, b = 7.7166(8) Å, c = 18.327(2) Å, V = 1755.6(3) Å³, and Z = 4 with R₁ = 0.0282, wR₂ = 0.0632. The novel 3D open framework is constructed from InO₆ octahedra, HPO₃ pseudo-tetrahedra and C₂O₄ units. The assembly of these building units generates intersecting 8- and 12-membered ring (MR) channels along two different directions. To the best of our knowledge, it is the first reported indium phosphite-oxalate hybrid material. Further characterization of compound 1 was performed using X-ray powder diffraction (XRD), infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP) and elemental analyses.     

Synthesis and characterization of nitrosyl complexes containing 4,6-dimethyl-pyrimidine-2-thiolato (‘SpymMe2’) as ligand: [Ru(‘SpymMe2’,-N,-S) (‘SpymMe2’,-S)(NO)(P–P)](PF6) (P–P = 1,2-bis(diphenylphosphino)ethane or 1,2-bis(diphenylphosphino)ethylene: X-ray structure of [Ru(‘SpymMe2’,-N,-S) (‘SpymMe2’,-S)(NO)(dppe)](PF6)

The reaction products of fac-[RuCl₃(NO)(P–P)], [P–P = dppe (1) and c-dppen (2)] with the 4,6-dimethyl-2-mercaptopyrimidine ligand in methanol are the correspondent nitrosyl derivatives [Ru(‘SpymMe₂’,-N,-S)(‘SpymMe₂’,-S)(NO)(P–P)](PF₆). These are the first reported ruthenium complexes containing both, nitrosyl and a pyrimidinethiol derivative. The X-ray crystal structure of complex 1 is reported. The intense ν_NO bands in the IR spectra (KBr pellets) of complexes 1 and 2 are at 1850 and 1860 cm⁻¹, respectively. The cyclic voltammetry of both complexes shows two reduction waves centered at the NO⁺ ligand.     

Synthesis,spectroscopic and structural aspects of triphenylantimony(V) complex with internally functionalized acetylferroceneoxime: Crystal and molecular structures of [C5H5FeC5H4C(CH3)NO]2SbPh3 and C5H5FeC5H4C(CH3)NOH

Triorganoantimony(V) complex (C₅H₅FeC₅H₄C(CH₃)NO)₂SbPh₃ (1) has been prepared by the reaction of Ph₃SbCl₂ with acetylferroceneoxime C₅H₅FeC₅H₄C(CH₃)NOH (2) in 1:2 molar ratio in anhydrous toluene. The complexes have been characterized by elemental analyses, IR and NMR (¹H and ¹³C) spectroscopic studies, and biologic activity was measured. And crystal structures of 1, 2 were reported. The coordination geometry around the antimony atom in 1 was slightly distorted trigonal bipyramidal with the carbon atoms of the SbPh₃ unit in equatorial positions and the two oxygen atoms of the oxime group occupying axial positions. The free oxime was clearly hydrogen bonded (H–N 2.10 Å/2.04 Å in 2) to essentially form a dimer.     

Supramolecular assembly of one-dimensional channels and two-dimensional brick-wall networks from asymmetric dithioether ligands and copper(I) iodide

Two asymmetric dithioether ligands with cyclohexyl (L¹) and phenyl (L²) end-groups were synthesized. Reaction of L¹ with copper(I) iodide afforded a 1D channel-type coordination polymer {[Cu₄I₄(L¹)₂](CH₃CN)_0.5}_n (1) interconnected by cubane-type tetranuclear Cu₄I₄ cluster units. Whereas, a 2D brick-wall-type coordination polymer [CuI(L²)]_n (2) with rhomboid dinuclear Cu–I₂–Cu nodes was isolated from the reaction of L² with copper(I) iodide.     

Two new 2D organic–inorganic hybrids assembled by lanthanide-substituted polyoxotungstate dimers and copper–complex linkers

Two new organic–inorganic hybrid copper–lanthanide heterometallic polyoxometalates (POMs), [Cu(dap)₂]_3.5[Cu(dap)₂(H₂O)]₃[La(α-SiW₁₁O₃₉)₂]·5H₂O (1) and H[Cu(dap)₂(H₂O)][Cu(dap)₂]₄[Eu(α-PW₁₁O₃₉)₂]·13H₂O (2) (dap = 1,2-diaminopropane), have been made under hydrothermal conditions and characterized by elemental analyses, IR spectra, XRD, thermogravimetric (TG) analyses and X-ray single-crystal diffraction. They both display interesting 2D organic-inorganic hybrid POMs containing 3d-4f cations and organic dap ligands. To the best of knowledge, 1 represents the first 2D Cu–Ln heterometallic silicotungstate assembled by [La(α-SiW₁₁O₃₉)₂]^13 − dimers and [Cu(dap)₂]^2 + linkers, while 2 is a new 2D Cu-Eu heterometallic Keggin-type phosphotungstate with dap ligands. Furthermore, the variable-temperature magnetic susceptibility of 2 has been investigated.     

Thermolytic conversion of a bis(alkoxy)tris(siloxy)tantalum(V) single-source molecular precursor to catalytic tantala–silica materials

The new complex (ⁱPrO)₂Ta[OSi(O ^tBu)₃]₃ (1) was prepared via silanolysis of Ta(O ⁱPr)₅ with (^tBuO)₃SiOH and is a useful structural and spectroscopic (NMR, FTIR) model of Ta(V) on silica. The complex was also used to prepare tantalum-containing silica materials, via the thermolytic molecular precursor method (yielding Ta₂O₅ ⋅ 6SiO₂ and Ta₂O₅ ⋅ 18SiO₂) or by grafting 1 onto mesoporous SBA-15 silica (yielding a surface-supported tantala species, TaSBA-15). The solution phase thermolysis of 1 in nonpolar media afforded homogeneous, high-surface-area (ca. 450 m² g⁻¹) xerogels (Ta₂O₅ ⋅ 6SiO₂) that are amorphous up to approximately 1100 °C. A more silica-rich tantala–silica material (Ta₂O₅ ⋅ 18SiO₂) was prepared via a solution-phase co-thermolytic route with 1 and HOSi(O ^tBu)₃, to yield a material with a Si/Ta ratio of 9/1. It was demonstrated that tantala–silica materials are active as catalysts for cyclohexene oxidation.     

Synthesis,structure and magnetic property of the first 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands

An unprecedented 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands [DMAH]₄{[Mn(DMF)₄]₂[Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]} (1) (DMA = dimethylamine, DMF = N,N-dimethylformamide) has been solvothermally synthesized and characterized by IR, UV spectra and X-ray single-crystal diffraction. The 2-D organic–inorganic hybrid network of 1 is built by tetra-Mn^II substituted sandwich-type polyoxotungstates [Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]^8? and [Mn(DMF)₄]²⁺ cation bridges, which displays the common 2-D (4,4) topological net. It should be noted that the major difference between [Mn₄(DMF)₂(α-B-HPW₉O₃₄)₂]^8? in 1 and the reported [Mn₄(H₂O)₂(α-B-PW₉O₃₄)₂]^10? is that two DMF ligands substitute two H₂O ligands on the Mn₄O₁₆ unit located in the sandwich belt. Magnetic susceptibility measurement indicates the occurrence of antiferromagnetic coupling interaction within Mn^II ions.     

β-Alanine Zn(II) and Cd(II) coordination complexes with diamondoid frameworks possessing second-order nonlinear optics properties

A complex, [Cd(HL)₄](NO₃)₂ (1) (HL = β-alanine), was synthesized and characterized by X-ray single crystal diffraction method, which crystallized in an acentric space group Fdd2 with supramolecular diamondoid frameworks and its second harmonic generation (SHG) efficiency has been tested. The ligand in complex 1 is electronically neutral. The counter-ion, NO₃⁻, interacts with β-alanine ligands by asymmetrical H-bonding connections, which induces the structural polarity of complex 1. Based on our understanding of SHG materials, we predicted and found another new SHG material, [ZnL₂]_n (2) with an acentric space group Cc, although the crystal data of complex 2 has been reported. The possible reasons for complex 2 possessing SHG property were discussed. The analysis about similar and dissimilar influence factors on constructing SHG materials between complex 1 and complex 2 will be useful for synthesizing and finding out more SHG materials.     

Sulfate binding in zinc(II) complexes of a monopyridylurea ligand N-(1-naphthyl)-N′-(3-pyridyl)urea

Two zinc(II) complexes of a urea-functionalized pyridyl ligand, [Zn(SO₄)L₃]·CH₃OH (1) and {[Zn(μ₂-SO₄)L₂]·0.5CH₃OH}_n (2) (L = N-(1-naphthyl)-N′-(3-pyridyl)urea), have been synthesized by the reaction of L with ZnSO₄·7H₂O under different conditions. Complex 1 is a hydrogen-bonded 2D grid structure in which the sulfate anion not only coordinates to the Zn^II ion as a monodentate ligand but also forms multiple hydrogen bonds with the urea groups of adjacent molecules. In complex 2 the sulfate ion serves as a μ₂-bridging ligand, connecting the Zn^II ions to form an infinite 1D organic–inorganic hybrid framework. Meanwhile, the sulfate anion is also bound by neighboring ligands through hydrogen bonds between urea groups and the non-coordinated oxygen atoms. The solid-state emission spectra of 1 and 2 show a red shift of the fluorescence emission of ligand L.     

Solvothermal synthesis and crystal structure of a luminescent 2D copper(I) coordination polymer with a (3,4)-connected net

A novel copper(I) coordination polymer, {[Cu(tpt)(MeCN)](ClO₄)}_∞ (1) (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), was synthesized by solvothermal synthesis method and structurally characterized. Single crystal X-ray diffraction showed that 1 consists of a 2D (3,4)-connected network with a unique (5³)₂(5⁴8²) topology. The luminescent properties of 1 in the solid state at ambient temperature were investigated.