Jianmin Dou

Family of Mixed 3d–4f Dimeric 14-Metallacrown-5 Compounds: Syntheses, Structures, and Magnetic Properties

An isomorphous family of mixed 3d-4f dodenuclear aggregates, {[Mn(III)8Ln4(Clshi)8(OAc)6(μ3-OCH3)2(μ3-O)2(CH3OH)12(H2O)2]·4CH3OH·xH2O)} (where Ln = Eu(III) (1), Gd(III) (2), Tb(III) (3), and Dy(III) (4); ClshiH3 = 5-chlorosalicylhydroxamic acid; x = 5 for 1 and 3; x = 6 for 2; x = 2 for 4), were synthesized and characterized. They were obtained from the reaction of ClshiH3 with Mn(OAc)2·4H2O and Ln(NO3)3·6H2O. These isomorphous mixed 3d-4f compounds represent a family of novel structures with lanthanide ions in the metallacrown (MC) ring. Each dodecanuclear aggregate contains two offset stacked 14-MC-5 units with M-N-O-M-N-O-Ln-O-N-M-O-N-M connectivity to capture one Ln(III) ion in the core of each MC. Two 14-MC-5 units are connected through O ions with four Mn ions and six O atoms arranged in a double Mn4O6 cubane. Magnetic measurement indicates that antiferromagnetic interactions are present between the metal ions. The Dy(III) analogue with high anisotropy and large spin shows slow magnetization relaxation at a direct-current field of 2 kOe.

Assembly of a series of d10 coordination polymers of pamoic acid through a mixed-ligand synthetic strategy: syntheses, structures and fluorescence properties

Eight mixed-ligand coordination compounds, [Zn(PA)(bpp)]n (1), {[Cd(PA)2(Hbpp)2(H2O)2]·2H2O}n (2), [Zn(PA)(bbi)]n (3), [Cd(PA)(bbi)(H2O)]n (4), {[Cd3(PA)2(bbi)3(Cl)2]}n (5), {[Zn6(PA)5(datrz)2(Hdatrz)2(H2O)2]·16DMF}n (6), [Cd2(PA)(datrz)2(DMF)2]n (7), and {[Cd2(PA)2(bix)2(DMF)2]·4DMF}n (8) (bpp = 1,3-bi(4-pyridyl)propane, bbi = 1,4-bis(imidazol-1-yl)butane, H2datrz = 3,5-diamino-1,2,4-triazole, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized through the reaction of zinc and cadmium salts with pamoic acid (H2PA) and different N-donor ligands. The assembly of the ligands in different coordination modes and conformations leads to fascinating structures. 1 and 3 afford an interpenetrating polythreaded 2D → 3D motif composed of 44 sql undulated sheets, while right- and left-helices are alternatively arranged in 3. 2 possesses an interesting 3-D supramolecular network with 1-D hydrogen-bonded chains spanning different directions. 4 and 5 display both polyrotaxane and polycatenane characteristics. In 4, two 2,4-connected (4·85) nets interlocked with each other, forming a 2D → 2D polycatenating network. 5 exhibits a twofold interpenetrated (3,5,6)-connected (3·5·6)(3·52·67)(32·54·66·72·9) topology. 6 and 7 represent rare pentanodal (3,4)-connected and binodal (3,4)-connected frameworks with topologies of (4·5·6)(4·8·10)(52·6·8·9·11)(4·5·6·8·92)(4·5·7) and (4·6·8)(4·62·83), respectively. 8 displays 3-fold interpenetrated 4-connected SrAl2 topology with flexible bix ligands bridging Cd centers to form right- and left-helices. The mixed-ligand effect of the conformations of the PA ligand and N-heterocyclic coligands as well as the metal centers on the assembly of frameworks is unravelled in detail. Solid-state luminescence properties of all compounds were reported as well. Moreover, fluorescence properties of compounds 6 and 8 in various solvent suspensions at room temperature have also been investigated.

Positional isomeric and substituent effect on the assemblies of a series of d10 coordination polymers based upon unsymmetric tricarboxylate acids and nitrogen-containing ligands

Seven novel compounds, {[Zn2(L1)2]·2H2N(CH3)2·DMF}n (1), {[Cd2(L1)2]·2H2N(CH3)2·DMF}n (2), [Zn(HL2)(bpe)]n (3), [Zn2(HL2)2(bpea)2(H2O)]n (4), {[Cd2(HL2)2(bpe)(H2O)2]·2H2O}n (5), {[Cd2(HL2)2(bpea)(H2O)2]·2H2O}n (6) and {[Zn(HL3)(bpea)]·2H2O}n (7), were constructed based on three unsymmetrical tricarboxylate ligands and nitrogen-containing ligands (H3L1 = biphenyl-3,4′,5-tricarboxylic acid, H3L2 = biphenyl-3,3′,5-tricarboxylic acid, H3L3 = biphenyl-3-nitro-5,3′,5′-tricarboxylic acid, bpe = 1,2-bi(4-pyridyl)ethylene, bpea = 1,2-bi(4-pyridyl)ethane) under hydrothermal conditions. The positional isomeric and substituent effects of these ligands lead to fascinating structures. Compounds 1 and 2 afford 3D (3,6)-connected (4.62)2(42.610.83) rutile topologies based on dinuclear M2(CO2)2 SBUs. Compounds 3 and 4 are 4-connected diamondoid nets, which exhibit unusual roto-translational [2 + 2]-fold and common 4-fold interpenetration due to the different weak interactions among each interpenetrating motif, respectively. Compounds 5 and 6 are isostructural, both presenting 2D unique undulated (3,4)-connected (42.6)(42.63.8) topologies. Compound 7 possesses a 2D → 3D parallel polycatenation framework composed of (4,4) undulated sheets. The effects of the positions of the carboxylate groups and the substituent groups on the aromatic rings, the flexibility of the N-containing coligands as well as the coordination geometry of the metal centers are discussed in details. The fluorescence properties and thermal stability of the ligands and compounds have also been performed.

Magneto-chiral dichroism in chiral mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker SMMs

Two new chiral mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes with both (R)- and (S)-enantiomers were synthesized and structurally characterized. The significant magneto-chiral cross effect revealed for the dysprosium compound suggests the great potential of sandwich-type tetrapyrrole rare earth systems in the research field of magneto-chiral dichroism.

A new Cd(II)-based metal–organic framework for highly sensitive fluorescence sensing of nitrobenzene

A Cd(II)-based metal–organic framework, {[Cd2L(H2O)2]·DMF·H2O}n (1), has been successfully constructed from a new flexible antler-like multidentate ditopic ligand (H4L). This metal–organic framework shows highly sensitive fluorescence sensing of nitrobenzene.

Pb(II) metal–organic nanotubes based on cyclodextrins: biphasic synthesis, structures and properties

Two chiral lead metal–organic nanotubes (CD-MONT-2 and CD-MONT-3) based on β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) were synthesized through a biphasic solvothermal reaction. The lead ions were connected by two β-CD or γ-CD molecules through their glycosidic oxygen atoms to generate a discrete metal–organic nanotube containing a {Pb14} or {Pb16} metallamacrocycle, respectively. Guest solvents of cyclohexanol molecules were trapped in the cavity of the β-CD-based nanotube, whereas there were no solvents in the cavity of the γ-CD-based nanotube. These differences directly led to the formation of different 3D packing structures. Their properties including temperature-dependent photoluminescence, adsorption of I2 molecules and thermal-decomposition behaviors were studied.

DMF/H2O Volume-Ratio-Controlled Assembly of 2D and 3D Ln-MOFs with 5-(Pyridin-4-yl)isophthalic Acid Ligand

Through middle-temperature solvothermal reactions of Ln(NO3)3·6H2O (Ln = Tb and Eu) with 5-(pyridin-4-yl)isophthalic acid (H2PIA), three Ln-MOFs [Tb(HPIA)(PIA)(H2O)2]n·0.5nH2O (1), [Eu(HPIA)(PIA)(H2O)2]n·0.5nH2O (2), and [Tb2(PIA)3(H2O)4]n·3nH2O (3) were obtained using DMF/H2O volume ratios of 1 : 54, 1 : 54, and 1 : 7, respectively. Single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 are isostructural and display a 2D uninodal 4-connected undulated sql topology with Ln3+ ions as nodes, while complex 3 exhibits a 3D uninodal 6-connected pcu topology with dinuclear octahedral [Tb2(CO2)6] secondary building units as nodes. Obviously, the DMF/H2O volume ratio plays an essential role in the crystallisation and construction of these coordination frameworks with distinct dimensionality and connectivity. The thermal and photoluminescence properties of complexes 1–3 in the solid state are also discussed.

Structural studies of the whole series of lanthanide double-decker compounds with mixed 2,3-naphthalocyaninato and octaethylporphyrinato ligands

The molecular structures of a series of nine mixed (2,3-naphthalocyaninato)(octaethylporphyrinato) double-decker complexes of lanthanide(III), M(Nc)(OEP) (M = La, Pr, Nd, Tb, Dy, Ho, Er, Tm, Yb), have been determined by single-crystal X-ray diffraction analysis. All these compounds together with the Sm, Eu, Gd, Y, Lu and Ce analogues, whose structures have been solved previously, crystallize in the same orthorhombic system, Pnma, Z = 4. The molecular structures of all these compounds are isostructural, exhibiting a slightly distorted square antiprismatic geometry with two domed ligands. The metal centre of M(Nc)(OEP) is coordinated by eight nitrogen atoms from the isoindole and pyrrole of the Nc and OEP rings, respectively. The ring-to-ring separation between the two domed ligands, as defined by the two N4 mean planes, decreases monotonically from 3.056 to 2.652 A along the series of La to Lu as a result of lanthanide contraction. This interplanar distance as well as the average M–N(Nc) and M–N(OEP) bond lengths of M(Nc)(OEP) (except M = Ce) show a linear relationship with the ionic radius of the metal centre. The skew/twist angle between the two macrocyclic rings remains almost unchanged, ca. 45°, for the whole series of lanthanide complexes, regardless of the size of the metal centre.

A linear tetranuclear single-molelcule magnet of Mn(II)(2)Mn(III)(2) with the anion of 2-(Hydroxymethyl)pyridine.

A tetranuclear manganese complex, [Mn(4)(hmp)(6)(N(CN)(2))(4)(H(2)O)(2)] [1; Hhmp = 2-(hydroxymethyl)pyridine; N(CN)(2)(-) = dicyanamide anion], was synthesized and characterized by single-crystal X-ray diffraction, bond valence sum calculations, IR spectra, elemental analysis, and magnetic measurements. The structure of 1 consists of a linear [Mn(II)(2)Mn(III)(2)] core formed by six hmp(-) groups linking Mn(II/III) ions. Magnetic studies show that 1 behaves as a single-molecule magnet with ferromagnetic coupling between the metal centers.

Peripheral Substitution: An Easy Way to Tuning the Magnetic Behavior of Tetrakis(phthalocyaninato) Dysprosium(III) SMMs

Two tetrakis(phthalocyaninato) dysprosium(III)-cadmium(II) single-molecule magnets (SMMs) with different extent of phthalocyanine peripheral substitution and therefore different coordination geometry for the Dy ions were revealed to exhibit different SMM behavior, providing an easy way to tuning and controlling the molecular structure and in turn the magnetic properties of tetrakis(tetrapyrrole) lanthanide SMMs through simple tetrapyrrole peripheral substitution.