[Co(2,2'-bipy)3]Ag3I6 with a hole structure facilitates dye adsorption and photocatalytic reduction.

We synthesized a new iodoargentate [Co(2,2'-bipy)3]Ag3I6 (1) (2,2'-bipy = 2,2'-bipyridine) via the reaction of AgI, KI, 2,2'-bipy and Co(NO3)2 in dimethylformamide (DMF) solvent at room temperature. The [Co(2,2'-bipy)3]3+ complex cation directs the formation of the 0 D cluster [Ag3I6]3- anion that features an irregular double-level gear wheel with a maximum diameter of 5.512 Å. The iodoargentate possesses the characteristics of semiconductors with a band gap of 2.03 eV. It exhibits excellent ion-exchange behavior for adsorbing crystal violet (CV) and methylene blue (MB), and it can function as a promising photocatalyst for degrading rhodamine B (RhB). The improved photocatalytic activity can be ascribed to the hole structure in the anions of iodoargentates.

Construction of an Entropy-Driven Dumbbell-Type DNAzyme Assembly Circuit for Lighting Up Uracil-DNA Glycosylase in Living Cells.

Sensitive monitoring of intracellular uracil-DNA glycosylase (UDG) in living cells is essential to understanding the DNA repair pathways and discovery of anticancer drugs. Herein, we demonstrate the construction of an entropy-driven dumbbell-type DNAzyme assembly circuit for lighting up UDG in living cells via the integration of entropy-driven DNA catalysis (EDC) with the DNAzyme biocatalyst. Target UDG excises the damaged uracil base, causing the breakage of detection probe and the release of trigger. The released trigger can initiate the downstream EDC reaction to form two catalytically active DNAzyme units. The resultant dual Mg2+-DNAzyme units serve as the signal transducers to cyclically cleave the fluorophore/quenched-modified reporters, generating an enhanced fluorescence signal. In contrast to the single-layered EDC method with a linear amplification, the proposed doublet EDC-DNAzyme strategy exhibits high signal gain and achieves a detection limit of 8.71 × 10-6 U/mL. Notably, this assay can be performed in one-step manner at room temperature without the requirement of strict temperature control and complicated reaction procedures, and it can further screen the UDG inhibitors, measure kinetic parameters, and discriminate cancer cells from normal cells. Moreover, this strategy can monitor intracellular UDG activity with improved signal gain, and it may be exploited for sensing and imaging of other types of DNA modifying enzymes with the integration of the corresponding detection substrate, providing a facile and robust approach for biological research studies and clinical diagnosis.

Transition-Metal-Complex-Directed Synthesis of Hybrid Iodoargentates with Single-Crystal to Single-Crystal Structural Transformation and Photocatalytic Properties.

We synthesized and characterized three types of isostructural iodoargentates, [TM(phen)3]Ag2I4·3DMF (TM = Co (1), Ni (2), Zn (3)), [TM(phen)3]Ag3I5·DMF (TM = Co (4), Ni (5), Zn (6)), and [TM(phen)3]2Ag8I12·7DMF (TM = Co (7), Ni (8), Zn (9)) (phen = 1,10-phenanthroline, DMF = dimethylformamide) using transition-metal (TM) complexes as the structure-directing agents. Compounds 1-3 and compounds 4-6 feature zero-dimensional anionic [Ag4I8]4- and [Ag6I10]4- clusters, respectively. All of the [TM(phen)3]2+ cations in compounds 1-6 are arranged into a two-dimensional (2D) (6,3) net layer. Interestingly, compounds 1-3 are kinetically unstable in the mother solution, and they can be converted to compounds 4-6 via irreversible single-crystal to single-crystal transformation processes, respectively, with distinct changes in the crystal morphology and structure. Compounds 7-9 feature one-dimensional (1D) zigzag chains constructed from [Ag8I12]4- units. The UV-vis diffuse reflectance measurements demonstrate that compounds 1-9 possess the characteristics of semiconductors with band gaps of 2.58-2.71 eV and visible-light-irradiation-induced photocatalytic activities. Especially, compound 3 possesses higher photocatalytic degradation activity toward crystal violet (CV) and rhodamine B (RhB) in comparison to P25 under identical conditions. Moreover, the mechanism study reveals that the TM complex cations make a great contribution to the photocatalytic activity.

Hydrazine-solvothermal methods to synthesize polymeric thioarsenates from one-dimensional chains to a three-dimensional framework.

A series of polymeric Mn(ii)-thioarsenates [Mn(en)3] n [(N2H4)2Mn6(µ6-S)(µ-N2H4)2(µ3-AsS3)4] n (1), [N2H5] n [{Mn(µ-N2H4)2(µ-AsS4)}·0.5en] n (2), [Mn(µ-trien){Mn(µ-N2H4)(µ-AsS3)}2] n (3), [{Mn(N2H4)}2(µ-N2H4)2{Mn(µ-N2H4)2(µ-AsS3)2}] n (4), [Mn3(µ-N2H4)6(µ3-AsS4)(µ2-AsS4)] n (5), and [Mn(NH3)6] n [{Mn(NH3)(µ-AsS4)}2] n (6) were synthesized using a hydrazine-solvothermal method. The thioarsenate units AsS3 and AsS4 coordinate to Mn(ii) ions with variable coordination modes, forming a Mn-As-S ternary cluster (1), chains (2, 4-6), and layers (3), respectively. The hydrazine molecules act as inter-cluster, intra-chain and intra-layer bridging ligands to join the Mn(ii) ions, resulting in hydrazine hybrid 1-D, 2-D, and 3-D Mn(ii)-thioarsenate moieties in 1-5. Compounds 1-6 exhibit tunable semiconducting band gaps varying in the range of 2.19-2.47 eV. Compound 1 displays stronger antiferromagnetic coupling interactions than that of compound 2.

Novel one-, two-, and three-dimensional selenidostannates templated by iron(II) complex cation.

The novel iron selenidostannates [Fe(bipy)3]Sn4Se9·2H2O (1) and [Fe(bipy)3]2[Sn3Se7]2·bipy·2H2O (2) (bipy = bipyridine) were prepared by the reactions of Sn, Se, FeCl2·4H2O, bipy, and dien with/without KSCN under hydrothermal conditions (dien = diethylenetriamine). In 1, four SnSe5 units condense via edge sharing to form the novel 3-D framework selenidostannate (∞)³[Sn4Se9²â»] containing an interpenetrating channel system. The [Fe(bipy)3]²âº cations are accommodated in the different channels according to the conformation of the [Fe(bipy)3]²âº cation. In 2, three SnSe5 units share edges to form a 2-D (∞)²[Sn3Se7²â»] layered anion, while two SnSe5 units and one SnSe4 unit are connected via edge sharing, forming a 1-D (∞)¹[Sn3Se7²â»] chainlike anion. The (∞)¹[Sn3Se7²â»], [Fe(bipy)3]²âº, bipy, and H2O species are embedded between the (∞)²[Sn3Se7²â»] layers. 2 is the first example of a selenidostannate constructed by both (∞)²[Sn3Se7²â»]and (∞)¹[Sn3Se7²â»] anions. The coexistence of 1-D (∞)¹[Sn3Se7²â»] and 2-D (∞)²[Sn3Se7²â»] anions in 2 might support the possible reaction mechanism that the (∞)²[Sn3Se7²â»] anions are formed by condensation of the (∞)¹[Sn3Se7²â»] chains. 1 and 2 exhibit band gaps at 1.43 and 2.01 eV, respectively.

Syntheses and properties of 2-D and 3-D Pb-Ag heterometallic iodides decorated with ethylene polyamines at the Pb(II) center.

Hybrid organic-inorganic Pb-Ag heterometallic iodides [(en)2(PbAgI3)]2n·nH2O (1), [(pda)2(PbAgI3)]n (2), [(tmeda)(PbAgI3)]n (3), [(trien)(PbAgI3)]n (4), [(tepa)(PbAg2I4)]n (5), and [{(dien)3(CO3)}2(Pb6Ag8I15)]nIn (6) were prepared by the reactions of PbI2, AgI (or Ag2CO3) and KI with different polyamines in N,N'-dimethylformamide (DMF) solution. In 1-4, two AgI4 tetrahedra share a common edge to form the bimeric Ag2I6 unit. It coordinates to the Pb(II) ion of [PbL2](2+) or [PbL'](2+) (L = en, pda; L' = tmeda, trien) via iodine atoms to form hybrid organic-inorganic heterometallic iodides 1, 2, 3 and 4, respectively. Compounds 1, 3, 4 and contain 2-D layered backbones of [PbAgI3]n, whereas 2 contains a backbone of [PbAgI3]n with a 3-D structure. Steric hindrance and denticity of the ethylene polyamines influence the coordination modes and connection strength between the iodoargentate aggregates and Pb(II) ions. In 5 the AgI4 units are joined via sharing common edges to form a 1-D polymeric [Ag2I4]n(2n-) anion. It is connected with [Pb(tepa)](2+)via iodine atoms to form a 3-D network of [(tepa)(PbAg2I4)]n. In 6, the CO3(2-) ion binds three [Pb(dien)](2+) units to form the novel trinuclear [{Pb(dien)}3(µ3-CO3)](4+) complex ion. Eight AgI4 tetrahedra are connected via sharing common edges to give a novel Ag8I15 cluster with C3 symmetry. The Ag8I15 cluster and the [{Pb(dien)}3(CO3)](4+) unit are connected to form a novel layered heterometallic iodometallate cation [{(dien)3(CO3)}2(Pb6Ag8I15)]n(n+)via sharing iodine atoms. Compounds 1-6 represent a new type of hybrid organic-inorganic heterometallic iodide containing coordinative organic components. Optical absorption spectra show a blue shift of the absorption edges for 1-6 compared with those of the bulk PbI2 and AgI solids.

Clusters [Co(As3S3)2]2-, [Ni(As3S3)2]2-, and [{Co(en)}6(µ3-S)4(AsS3)4]2- with Co-As or Ni-As bonds: solvothermal syntheses and characterizations of thioarsenates containing transition-metal complexes.

Solvothermal reactions of As2O3 and S with CoCl2·6H2O or NiCl2·6H2O in an aqueous solution of dien produced novel thioarsenates [Co(dien)2][Co(As3S3)2] (1) and [Ni(dien)2][Ni(As3S3)2] (2) (dien = diethylenetriamine), and the reaction with CoCl2·6H2O in an aqueous solution of en afforded complex [Hen]2[{Co(en)}6(µ3-S)4(AsS3)4] (3) (en = ethylenediamine). In 1 and 2, one transition-metal ion is coordinated by two dien ligands to form [TM(dien)2](2+) (TM = Co, Ni) complex cations. The As3S3 unit coordinates to the other TM(II) ion with both As- and S-donor atoms to form the [TM(As3S3)2](2-) anionic cluster, in which TMAs2, TMAs2S2, and TMAs3S2 rings are formed. In 3, each Co(3+) ion is coordinated by an en ligand. Six Co(en) units are interlinked by four µ3-S and four AsS3 ligands to form a [{Co(en)}6(µ3-S)4(AsS3)4](2-) cluster containing an adamantane-like Co6S4 core. The AsS3 unit coordinates to Co atom in the η(1)-As1,η(2)-S coordination mode with As binding Co(1) and S(1) binding Co(1) and Co(2). The As3S3 and AsS3 ligands with both As- and S-donor atoms in 1-3 have never been obtained in amine solution before. The same reactions in pure dien and en solvents afforded compounds [Co(dien)2]3[As3S6]2 (4) and [Co(en)3]2As2S5 (5) containing discrete anions [As3S6](3-) and [As2S5](4-), respectively. The band gaps of 1-3 are in the range of 1.37-1.55 eV, and the band gaps of 4 and 5 are 2.24 and 2.26 eV, which show the influence of the coordination mode of thioarsenate ligands on the electronic transitions in the TM-thioarsenates.

Polymeric heterometallic Pb-Ag iodometallates, iodoplumbates and iodoargentates with lanthanide complex cations as templates.

Heterometallic Pb-Ag iodometallates [Ln(DMF)8]2Pb3Ag10I22 [Ln = Ce(1), Pr(2)] were prepared by the reactions of PbI2, AgNO3 and KI in dimethylformamide (DMF) templated by [Ln(DMF)8](3+) complexes formed in situ by stirring LnCl3 in DMF. The same reactions in the absence of AgNO3 or PbI2 afforded iodoplumbate [Pr(DMF)9]2[Pr(DMF)8]Pb11I31 (3), and iodoargentates [Ln(DMF)8]Ag6I9 [Ln = Ce(4), Pr(5)], respectively. Compounds 1 and 2 contain a ternary one-dimensional polymeric [Pb3Ag10I22](6-) anion self-assembled from five AgI4, one PbI6 and one PbI4 primary units via edge- and face-sharing. Twelve PbI6 octahedra are interlinked via sharing of common faces to generate a 1D zigzag [Pb11I31(9-)]n chain in 3, which represents a new member of iodoplumbate aggregates. In 4 and 5, three AgI4 tetrahedra connect through common edges to form the [Ag6I12](6-) building block. The [Ag6I12](6-) blocks are further interlinked by sharing common edges, resulting in the 1D [Ag6I9(3-)]n chain. Optical absorption spectra showed that the synthesized Ag-iodoplumbate and iodoplumbate have potential for being used as semiconductors. Our results show that heterometallic halometallate properties can be tuned by combining structural units with different symmetries, enabling the synthesis of specific functional materials.

Heterometallic clusters [CuSn3S9]5⁻ and [Cu6Sn6S20]¹°â»: solvothermal synthesis and characterization of 4f-3d thiostannates.

Two types of 4f-3d thiostannates with general formula [Hen]2[Ln(en)4(CuSn3S9)]∙0.5 en (Ln1; Ln=La, 1; Ce, 2) and [Hen]4[Ln(en)4]2[Cu6Sn6S20]∙3 en (Ln2; Ln=Nd, 3; Gd, 4; Er, 5) were prepared by reactions of Ln2O3, Cu, Sn, and S in ethylenediamine (en) under solvothermal conditions between 160 and 190 °C. However, reactions performed in the range from 120 to 140 °C resulted in crystallization of [Sn2S6]4⁻) compounds and CuS powder. In 1 and 2, three SnS4 tetrahedra and one CuS3 triangle are joined by sharing sulfur atoms to form a novel [CuSn3S9]5⁻ cluster that coordinates to the Ln(3+) ion of [Ln(en)4]³âº (Ln=La, Ce) as a monodentate ligand. The [CuSn3S9]5⁻ unit is the first thio-based heterometallic adamantane-like cluster coordinating to a lanthanide center. In 3-5, six SnS4 tetrahedra and six CuS3 triangles are connected by sharing common sulfur atoms to form the ternary [Cu6Sn6S20 ]¹°â» cluster, in which a Cu6 core is enclosed by two Sn3S10 fragments. The topological structure of the novel Cu6 core can be regarded as two Cu4 tetrahedra joined by a common edge. The Ln³âº ions in Ln1 and Ln2 are in nine- and eightfold coordination, respectively, which leads to the formation of the [CuSn3S9]5⁻ and [Cu6Sn6S20]¹°â» clusters under identical synthetic conditions. The syntheses of Ln1 and Ln2 show the influence of the lanthanide contraction on the quaternary Ln/Cu/Sn/S system in ethylenediamine. Compounds 1-5 exhibit bandgaps in the range of 2.09-2.48 eV depending on the two different types of clusters in the compounds. Compounds 1, 3, and 4 lost their organic components in the temperature range of 110-350 °C by multistep processes.