Solvent-free synthesis of open-framework manganese phosphate-oxalates with 4-connected topologies

Two manganese phosphate-oxalates, namely, H₂aep·Mn₂(H₂PO₄)₂(C₂O₄)₂·H₂O (1) and H₂epip·Mn₂(H₂PO₄)₂(C₂O₄)₂ (2), were prepared under solvent-free conditions, where aep = 1-(2-aminoethyl)piperazine and epip = 1-ethylpiperzaine. The two hybrid solids have three-dimensional open-framework structures with 12-, and 16-ring channels, respectively. Topological analysis reveals that they have 4-connected lon and mog nets. The magnetic properties of the two compounds were also investigated.     

Solvent control on the structural versatility and properties of manganese(II) complexes surrounded by the flexible hinge-like ligand

Four different types of polynuclear manganese(II) compounds with bhnq^2? bridges were obtained from the reaction of Mn(CH₃COO)₂·4H₂O with the flexible hinge-like ligand H₂bhnq (H₂bhnq = 2,2′-bi(3-hydroxy-1,4-naphthoquinone)) by controlling the reaction solvent: [Mn₃(bhnq)₃(H₂O)₂]·10.5H₂O (1), [Mn₂(bhnq)₂(DMSO)₄]·2DMSO·CHCl₃ (2), {[Mn(bhnq)(H₂O)₂]·2H₂O}_n (3), and {[Mn(bhnq)(DMF)₂]}_n (4). All complexes are neutral with the same Mn/bhnq 1:1 formulation ratio. Compounds 1 and 2 are discrete systems, while compounds 3 and 4 are one-dimensional ones. All compounds were characterized by X-ray diffraction and show different coordination modes for the bhnq^2? ligand.     

Spectroscopic studies on bis(1-amidino-O-alkylurea) copper(II) sulfate complexes where alkyl = methyl,ethyl, n-propyl or n-butyl: EPR evidence for binuclear complexes

Four new Cu(II) Complexes viz. [Cu(II)(1-amidino-O-methylurea)₂]SO₄·2H₂O (1), [Cu(II)(1-amidino-O-ethylurea)₂](SO₄)₂·2H₂O (2), [Cu(II)(1-amidino-O-n-propylurea)₂] SO₄·2H₂O (3), [Cu(II)(1-amidino-O-n-butylurea)₂]₂(SO₄)₂·2H₂O (4) have been synthesized and characterized. EPR spectrum of complex 4 at RT consisted of fine-structure transitions (ΔMs = ±1) with zero-field splitting (ZFS) of 0.0485 cm^?1 and a half-field signal (ΔMs = ±2) at ca. 1600 G, revealed formation of binuclear complex (S = 1). Whereas EPR spectrum of complex 2 in DMSO showed a mixture of mononuclear and binuclear complex in the ratio 0.75:1.0 with ZFS of 0.0385 cm^?1. From the temperature dependence of the EPR signal intensity, the isotropic exchange-interaction constant J was evaluated.     

Co-existence of heterometallic Zn2Er and ZnEr arrayed chromophores for the sensitization of near-infrared (NIR) luminescence

With the Zn-Schiff-base [ZnL(Py)] from the simple Salen-type Schiff-base ligand H₂L (H₂L = N,N′-bis(salicylidene)ethylene-1,2-diamine) as the precursor, two co-crystallized heterometallic (Zn₂Ln and ZnLn array) complexes [Zn₂Ln(L)₂(Py)₂(NO₃)₂]·[ZnLn(L)(Py)(NO₃)₃(H₂O)]·NO₃·mMeOH·nS (Ln = Er(1), S = CH₃CN, m = 2, n = 1 or Gd(2), S = H₂O, m = 1, n = 3) were obtained by the further reaction with Ln(NO₃)₃·6H₂O, respectively. The result of their photophysical properties shows the intramolecular effective energy transfer has been demonstrated in the Zn₂Er and ZnEr arrayed complex 1, and the co-existence of different chromophores should be a potentially new way to the fine-tuning properties of NIR luminescence from Er³⁺ ions.     

Multiple functions of amines in the synthesis of anionic,cationic, and neutral indium oxalates

Three new indium oxalates, formulated as H₃dpta·In(C₂O₄)(H₂O)₃·2SO₄ (1), In(qd)(C₂O₄)_1.5·1.5H₂O (2), and H₂bpp·In₂(C₂O₄)₄ (3) in which dpta = dipropylenetriamine, qd = quinoxaline-2,3(1H,4H)-dione, and bpp = 1,3-bis(4-piperidyl)propane, were prepared in the presence of different amines. These compounds have cationic, neutral, and anionic frameworks, respectively. Topological analyses reveal that compound 2 has an hcb net, while compound 3 has a dia net. The photoluminescent property of compound 2 was also investigated.     

Two corrugated 2D bilayer (63)(658) topological coordination polymers: Synthesis,structure, and water-induced reversible transformation

Two stable supramolecular microporous polymers with double-layer structures, [Co(AIP)(BPY)_0.5 · H₂O]_n · 2nH₂O (1) and [Ni(AIP)(BPY)_0.5 · H₂O]_n · 2nH₂O (2), were constructed from AIP (5-aminoisophthalate) and BPY (4,4′-bipyridine) under hydrothermal conditions. Both of them exhibit rarely reported (3,4)-connected (6³)(6⁵8) topology and interesting water-induced reversible transformation properties that are confirmed by PXRD studies.     

A helical salicyladoxime-based manganese triangle chain with single-molecule magnet behavior

The reaction of 2-hydroxyphenylpropanone oxime (Et-H₂salox) with Mn(NO₃)₂·4H₂O, NEt₃ and 1,3-bis(4-pyridyl)propane-N,N′-dioxide (bppo) in EtOH/H₂O mixture afforded a one-dimensional coordination polymer with the formula [Mn₃O(Et-salox)₃(bppo)(MeOH)(H₂O)₃](NO₃)_0.5(Et-Hsalox)_0.5·MeOH·H₂O (1·MeOH·H₂O). 1·MeOH·H₂O had a manganese triangle structure, [Mn^III₃O]^7 +, which was used as a building unit for a subsequent assembly of an oximate and central oxide. The flexible bppo ligand linked the units, resulting in the formation of a 1D helical structure. Variable temperature direct current magnetic susceptibility measurements of complex 1·MeOH·H₂O were carried out. Exchange interactions of the metal centers of complex 1·MeOH·H₂O were examined, and the results indicate that both ferro- and antiferromagnetic interactions simultaneously coexist in 1·MeOH·H₂O, resulting in an S = 2 ground state. Moreover, complex 1·MeOH·H₂O shows the frequency dependence of the out-of-phase component in alternating current magnetic susceptibility measurements, indicating single-molecule magnet behavior with U_eff = 28 K and τ₀ = 1.8 × 10^− 9 s.     

Synthesis and characterization of a new 2D trimetallic Mn/Ca/Na complex

A new tri-metallic Mn/Ca/Na coordination polymer, {[Mn₃NaCa(sal)₆(H₂O)₆]·7H₂O}_n (1·7H₂O), has been synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy, and magnetic measurements. The X-ray analysis shows 1 consists of a 2D homochiral (6,3) network with chiral [Mn₃Na] clusters and chiral Ca ions as alternating nodes. Magnetic property study reveals the existence of weak antiferromagnetic couplings between Mn(III) ions with the interaction parameter J being ? 0.438 cm^? 1 within the complex.     

A novel 3D twofold interpenetrating microporous metal-organic framework containing 1D water tapes with cyclic pentamer units

The self-assembly of Cu²⁺ ions with malate and 1,3-bis(4-pyridyl)propane (bpp) affords a 3D coordination polymer {[Cu(Hmal)(bpp) · 6H₂O]}_n (1) (malic acid = H₃mal). The metal ions were interconnected by α- and β-carboxylate of malate produce infinite [Cu(C₄H₄O₅)]_n layers, which were further pillared by bridging ligand bpp molecules to form a 3D interpenetrating network. Of further interest, lattice water molecules form 1D infinite water tapes in 1D open cavities.     

Structures and photoluminescence of coordination polymers assembled from bifunctional ligand containing both tetrazole and imidazole groups

Three new coordination polymers, namely, {[Cu₂(IPT)(SO₄)(OH)(H₂O)]·H₂O}_n (HIPT = 5-(4-(1H-imidazol-1-yl)phenyl)- 1H-tetrazolate, 1), {[Cd₂(IPT)(NPA)(OH)]·H₂O}_n (H₂NPA = 5-nitroisophthalic acid, 2), and {[Zn₂(IPT)(IDC)(H₂O)]·3H₂O}_n (H₃IDC = 1H-imidazole-4,5-dicarboxylic acid, 3), were assembled from a bifunctional organic ligand containing both tetrazole and imidazole groups with/without the aid of carboxylate coligands. Compound 1 possesses 2D structure built by 1D [Cu₂(IPT)(SO₄)(OH)]_n secondary building blocks and IPT⁻ linkers. The 2D networks are linked into 3D supramolecular framework via water chains in helical conformation. Compound 2 displays 3D pillar-layer framework with 2D layers based on tetranuclear Cd(II) SBUs and NPA^2 − pillars. Compound 3 exhibits a 3D framework constructed from the interconnection of 1D [Zn-IDC]_n chains and binuclear Zn₂(IPT)₂ rings. The thermal stabilities of porous compound 3 and luminescent properties of compounds 2 and 3 have also been studied in detail. They exhibit intense solid-state fluorescent emissions at room temperature.     

Bis-boron-capped tris(dioxime) cage complexes with terminal carbonyl groups

Three clathrochelate complexes, [(p-OHCC₆H₄B)₂(chdd)₃Fe^II]·0.5CH₂Cl₂ (1·0.5CH₂Cl₂, H₂chdd = 1,2-cyclohexanedione-1,2-dioxime), [(p-OHCC₆H₄B)₂(hmbd)₃Mn^II₂]}·Et₃NH·0.5CH₃OH·0.5H₂O (2·0.5CH₃OH·0.5H₂O, H₃hmbd = 2-hydroxy-5-methyl-1,3-benzenedicarboxaldehyde-1,3-dioxime), and [(p-OHCC₆H₄B)₂(hmbd)₃Co^II₂]·Et₃NH·H₂O (3·H₂O), were synthesized through template macrobicyclization using metal-oximates as building blocks. These complexes contained reactive apical formyl substituents. Fe^II in mononuclear complex 1 was wrapped in the cavity formed by condensation of H₂chdd with 4-formylphenylboron acid. The organic frameworks of anion unit of binuclear Mn^II complex 2 and that of binuclear Co^II complex 3 were combined by H₃hmbd with 4-formylphenylboronic acid. Spectroscopic, electrochemical characterizations of complexes 1–3 were exploited. DFT calculation of 1 and 2 was also done for better understanding of the electronic property and charge carrier mobility.     

Three-dimensional 3d–4f heterometallic coordination polymer containing Sm2Mn4 clusters: Synthesis,crystal structure and properties

Heterometallic coordination polymers of the form {[SmMn₂(imdc)₂(OAc)(H₂O)]·2H₂O}_n (1) (H₃imdc = 4,5-imidazoledicarboxylic acid, HOAc = acetic acid) were hydrothermally synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The results reveal that 1 has a three-dimensional framework containing Sm₂Mn₄ clusters. The luminescence and magnetic properties of 1 were also investigated.     

1D helical ZnII metal–organic polymers: Syntheses,structures and fluorescent properties

Hydrothermal reactions of 1,1′-(1,5-pentanediyl)bis-1H-benzimidazole (pbbm) with ZnCl₂ afford two 1D helical metal–organic polymers {[ZnCl₂(pbbm)] · (H₂O)_1/8}_n (1) and {[Zn(pbbm)₂] · Cl₂ · (H₂O)_1/2}_n (2). Polymer 1 features a 1D single helical architecture, whereas 2 possesses a 1D cationic double helical chain framework. Photoluminescence investigations reveal that both of them display strong emissions in the solid state at room temperature, which could originate from a ligand-to-ligand charge-transfer (LLCT) transition, as confirmed by the molecular orbital (MO) calculations.     

Two novel 3D 3d–4f polymers with triethylenetetraaminehexaacetic acid: Syntheses,structures, and magnetic properties

Two novel 3d–4f polymers [La(H₂O)₄][M₂TTHA(SCN)₂] · H₃O⁺ (M = Ni(1), Cu(2), H₆ TTHA = triethylenetetraaminehexaacetic acid) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, IR and magnetic properties. Two complexes show 3D framework, comprising an unusual infinite 1D chain based on heterometallic La₂M₂ rings (M = Ni(1), Cu(2)).     

Polycatenated (4, 4) lanthanide(III) coordination networks based on apidate: Synthesis,structure and properties

Three rare earth coordination polymers, {[Ln₂(μ₃-ADI)₂(μ₂-ADI)(H₂O)₄]·H₂O}_n (Ln = Tb, 1; Eu, 2; Er, 3; ADI = adipate), which show the inclined interpenetration of (4, 4) nets and bright luminescence, were isolated from H₂PDC-assisted (H₂PDC = pyridine-2,3-dicarboxylatic acid) hydrothermal reactions of H₂ADI and Ln₂O₃.     

One-dimensional supramolecular assembly of an Mn12 single molecule magnet by ligand interactions

A new Mn₁₂ complex was synthesized using ligand substitution reaction of Mn₁₂–OAc with 4-(thiophen-3-yl)benzoic acid and complex’s structural and magnetic properties were analysed. [Mn₁₂O₁₂(O₂CC₆H₄C₄H₃S)₁₆(H₂O)₃]·14CH₂Cl₂ (1) crystallized in the P2₁/c space group. Intermolecular π–π interactions between phenyl and thiophene rings of two adjacent Mn₁₂ molecules result in one-dimensional supramolecular assembly of 1 in the crystal. On the other hand, steric repulsion between the neighbouring molecules causes unusual ligand arrangement and coordination geometry of Mn(III) ion with five coordination. The ac magnetic study of 1 gives U_eff = 69.98 K and 1/τ₀ = 1.456 × 10⁸ s^?1 and dc reduced magnetization measurement gives S = 10, g = 1.95 and D = ?0.425 cm^?1 showing that outer ligand distortion has little effect on the magnetic properties.     

1D chain lanthanide coordination polymers with 6-hydroxynicotinic acid: Crystal structures and luminescent properties

Four new lanthanide coordination polymers {[Ln(HL)₂(H₂O)₅] · HL ·  H₂O}_n (Ln = Sm for 1, Eu for 2, Tb for 3 and Dy for 4) (H₂L = 6-hydroxynicotinic acid) have been synthesized and characterized by elemental analysis, FT-IR spectra and X-ray single-crystal diffraction. They all exhibit 1D chain structure, which are further linked via hydrogen bonds to form 3D supramolecular architecture. Luminescent properties of these lanthanide coordination polymers are studied.     

A new 3D cobalt(II) complex with left- and right-handed helical channels

A new 3D complex, {[Co(btec)_0.5(imb)(H₂O)]∙1.5H₂O}_n (1) (imb = 2-(1H-imidazol-1-methyl)-1H-benzimidazole, H₄btec = 1,2,4,5-benzenetetracarboxylic acid) has been synthesized by solvothermal technique. X-Ray diffraction analysis indicates that complex 1 displays a 3D framework with left- and right-handed helical channels and very high porous, which can be simplified as a 4,4,4-connected 3D topology with a Schläfli symbol of (3² · 10³ · 11)(3² · 10⁴)(3² · 10³ · 11). Moreover, its IR spectra, PXRD patterns, thermogravimetric curves, and luminescent emissions were studied at room temperature.     

Unusual metal–organic network constructed from Zn(II), benzenetricarboxylate and bis(1,2,4-triazolyl)pyridine

Hydrothermal reaction of ZnSO₄ · 7H₂O with 1,3,5-benzenetricarboxylic acid (H₃btc) and 2,6-bis(1,2,4-triazolyl)pyridine (btp) afforded a novel metal–organic network {[Zn₃(btc)₂(btp)₂(H₂O)₂] · 4H₂O}_n (1) with a supramolecular cocrystal [H₃btc · btp · H₂O]_n (2). The complex 1 exhibits an unusual network containing two molecular squares and a rectangle. The networks interpenetrate to make a 3D metal–organic framework, which is quite thermal stable. Compound 2 shows a 2D supramolecular network assembled through strong hydrogen bonds.     

Two organic–inorganic hybrid materials based on the penta-nuclear {MMn4} (M = W and Mo) heterometallic clusters and Schiff-base ligands

Two organic–inorganic hybrid compounds with the formula {[Mn^III(Salen)(H₂O)]₄MoO₄}·Cl₂·16H₂O (1) and {[Mn^III(Salen)(H₂O)]₄WO₄}·(CH₃COO)₂·11H₂O (2) (Salen = Di-[2-hydroxyl-3-methoxyl-benzaldehyde] ethylenediamine) have been synthesized and structurally characterized by IR, UV–vis spectroscopy, TG analysis and single crystal X-ray diffraction. Structural analysis revealed that compounds 1 and 2 consist of a [MoO₄]^2 − or [WO₄]^2 − building unit and four {[Mn^III(Salen)(H₂O)]⁺ metal–organic moieties, respectively. In the crystal structure, the [MoO₄]^2 − or [WO₄]^2 − tetrahedra coordinated with four Mn^III ions, resulting in the penta-nuclear heterometallic tetrahedra cluster compounds, which were rarely observed in the Mn-Salen system. Magnetic study revealed that there was antiferromagnetic coupling in the two compounds.