Aggregation-induced emission of ruthenium(II) polypyridyl complex [Ru(bpy)2(pzta)]2+

A new ruthenium(II) complex [Ru(bpy)₂(pzta)]²⁺ (1) [bpy = 2,2′-bipyridine; pzta = 6-(pyrzin2-yl)-1,3,5-triazine-2,4-diamine] has been synthesized and characterized. This complex exhibits a typical aggregation-induced emission (AIE) behavior that it is faint in solution but intense in the aggregate state.     

Synthesis,structures and catalytic activities of half-sandwich ruthenium complexes based on Schiff Base ligands

A series of half-sandwich ruthenium(II) complexes containing Schiff-base ligands [Ru(p-cymene)LCl] [HL = (E)-4-X-2-((phenylimino)methyl)phenol, X = H (2a); X = CH₃ (2b); X = Cl (2c) and X = Br (2d)] have been synthesized and fully characterized by ¹H and ¹³C NMR spectra, elemental analyses and infrared spectrometry. Moreover, the molecular structures of ruthenium complexes 2b and 2c were confirmed by single-crystal X-ray diffraction methods. These half-sandwich ruthenium complexes are highly catalyzed hydrogenation of nitroarenes to aromatic anilines to proceed in the presence of sodium borohydride reducing agent in ethanol solvent. Notably, complex 2c was found to be a very efficient catalyst toward reduction of nitroarene compounds with wide functional group compatibility and substrate scope.     

Trinuclear Ru(II) polypyridyl complexes as human telomeric quadruplex DNA stabilizers

Two new trinuclear ruthenium(II) complexes [(bpy)₆Ru₃(tpbip)]⁶⁺ (1) and [(bpy)₆Ru₃(tptaip)]⁶⁺ (2) (bpy = 2,2′-bipyridine, tpbip = 1,3,5-tris(1,10-phenanthroline-[5,6-d]imidazol-2-yl)-benzene, tptaip = 2,4,6-tri(1,10-phenanthroline-[5,6-d]imidazol-2-yl)-1,3,5-triazine) have been synthesized and characterized. The interaction of human telomeric DNA with Ru(II) complexes was explored by means of CD spectroscopy, fluorescence titration, ITC and FRET melting. Results indicated that two complexes not only induce a remarkable conformational change of human telomeric DNA, but also have the ability to stabilize the G-quadruplex.     

pH responsive “off–on–off” luminescent switch of a novel ruthenium(II) complex [Ru(bpy)2(pipipH2)]2+

A novel ruthenium(II) complex, [Ru(bpy)₂(pipipH₂)](ClO₄)₂ · H₂O (1) (pipipH₂ = 2-(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-1H- imidazo[4,5-f][1,10] phenanthroline, bpy = 2,2^′-bipyridine) has been found to act as a luminescent pH switch with extraordinary sensitivity through protonation and deprotonation of the bis-imidazole-containing ligand pipipH₂ in aqueous solution at room temperature.     

(CH3NH3)2[Ge(B4O9)]: An organically-templated chiral borogermanate with second-order nonlinear and ferroelectric properties

An organically-templated chiral borogermanate (CH₃NH₃)₂[Ge(B₄O₉)] (1), has been solvothermally synthesized and characterized by elemental analysis, IR, PXRD, TGA, single-crystal X-ray diffraction and UV–vis spectrum. It crystallized in the monoclinic space group C2 (No. 5) with a = 10.249(1) Å, b = 9.449(1) Å, c = 6.956(2) Å, β = 131.76(2)°, V = 502.43(19) Å³, Z = 2. The structure is constructed by alternate linkage of GeO₄ tetrahedra and B₄O₉ clusters to form a zeotype framework with diamond topology. Four intersecting channels with different sizes are observed. Large circular 10-ring channels are clearly extended along the [001] direction, 9-ring channels are running along the [101], [110], and [112] directions, respectively. Additionally, two pairs of the right- and left-handed channels couple together along the [100] and [010] directions, respectively. The preliminary investigations show that compound 1 exhibits second-harmonic generation (SHG) response and ferroelectric properties.     

Synthesis,characterization and compared reactivity of asymmetrical ansa-metallocenes

Rac and meso ansa-zirconocenes [Zr{1-Me₂Si(3-R-(η⁵-C₉H₅))(3-R′-(η⁵-C₉H₅))}Cl₂] (R = Et, R′ = H; R = Pr, R′ = H; and R = Et, R′ = Pr) 4–9 have been prepared by the reaction of ZrCl₄ with the corresponding dilithiated derivatives from the ligands {1-Me₂Si(3-R-(η⁵-C₉H₅))(3-R′-(η⁵-C₉H₅))} (R = Et, R′ = H 1; R = Pr, R′ = H 2; and R = Et, R′ = Pr 3) in diethyl ether/toluene at ?78 °C. The molecular structure of rac [Zr{1-Me₂Si(3-Et-(η⁵-C₉H₅))(3-Pr-(η⁵-C₉H₅))}Cl₂] 8 has been determined by single crystal X-ray diffraction studies, which show a pseudotetrahedral environment formed by the two chlorine ligands and two η⁵-coordinated indenyl ligands. The activity in homogeneous and heterogeneous polymerization is compared and discussed.     

Temperature dependence of dual emission in ruthenium(II) complexes containing 3,3′-bi-1,2,4-triazine derivatives

Three new ruthenium(II) polypyridyl complexes with highly π-deficient ligands, [Ru(bpy)₂(btm)]²⁺ (1), [Ru(bpy)₂(btb)]²⁺ (2) and [Ru(bpy)₂(btp)]²⁺ (3) (bpy = 2,2′-bipyridine, btm = 3,3′-bis(5,6-dimethyl-1,2,4-triazine, btb = 3,3′-bis(5,6-diphenyl-1,2,4-triazine, btp = 3,3′-bis(phenanthro[9,10-e][1,2,4]triazine) were synthesized and characterized. Electrochemical data together with molecular calculations show that the first redox process in these complexes is not bpy based. Complexes 1, 2 and 3 display luminescence in ethanol/methanol (4/1, V/V) at 80 K, and all three complexes exhibit a temperature switch from single (150 K) to dual (80 K) emission behavior.     

Synthesis of enantiomers of mononuclear Ru(II) complexes with 10,13-diaryl substituted dppz ligands

An array of enantiomerically pure mononuclcear [Ru(bpy)₂(dppz)]^2 + derivatives with 10,13-diaryl substituted dppz ligand has been synthesized and characterized (bpy = bipyridine, dppz = pyrido-[3,2-a:2′,3′-c]phenazine). These new complexes exhibit substantially similar absorption spectra, resembling the parent complex [Ru(bpy)₂(dppz)]^2 +, and the enantiomerically pure analogues show the similar CD spectra in buffer solution despite the structural difference.     

A new polymorph telluridoindate [In(en)3][In5Te9(en)2] with photocatalytic properties

A new polymorph telluridoindate [In(en)₃][In₅Te₉(en)₂] (denoted as β-type, en = ethylenediamine) has been solvothermally synthesized and characterized. The crystal data for the β-type are listed as follows: monoclinic, space group Cc (No. 9), a = 11.642(2), b = 20.421(4), c = 17.577(4) Å, β = 92.20(3)°, V = 4175.7(14) Å³, Z = 4. The β-type contains organic-decorated [In₄Te₉(en)]^6 − supertetrahedral cluster and [InTe₃(en)]^3 − tetrahedron, which are interconnected to form an organic-decorated 2-D telluridoindate layer of [In₅Te₉(en)₂^3 −]_n with 9-membered rings. Two relevant conformers of telluridoindates are compared with each other. The β-type indicates absorption edge at 2.23 eV and exhibits photocatalytic activity for degradation of methyl orange (MO).     

A new polyborate anion, [B7O9(OH)6]3−: Self assembly,XRD and thermal properties of s-fac-[Co(dien)2][B7O9(OH)6]·9H2O

The title compound, s-fac-[Co(dien)₂][B₇O₉(OH)₆]·9H₂O (1) (dien = HN(CH₂CH₂NH₂)₂), has been prepared as a crystalline solid in moderate yield (35%) from the reaction of B(OH)₃ with [Co(dien)₂][OH]₃ in aqueous solution (10:1 ratio). The structure contains a novel polyborate anion [B₇O₉(OH)₆]^3 − which is structurally based on the known ‘ribbon’ isomer of [B₇O₉(OH)₅]^2 −, with an additional [OH]⁻ group coordinated to a B atom in one of the outer boroxole rings. Compound 1 is formed by a self-assembly process in which the cation and anion mutually template themselves from equilibrium mixtures under reaction conditions. The [B₇O₉(OH)₆]^3 − anions are H-bonded to each other in layers with ‘cavities’ suitable for the [Co(dien]₂]^3 + complex. Three [B₇O₉(OH)₆]^3 − anions are in the secondary coordination sphere (via H-bonds) of each cation, with each anion H-bonded to three cations.     

Nitrosyl cis-dichlorodiammine ruthenium complex with bridging H3O2− ligand

The ruthenium complex with bridging H₃O₂⁻ ligand was obtained and the crystal structure was determined. The compound cis-[{RuNO(NH₃)₂Cl₂}₂(μ₂-H₃O₂)]Cl crystallizes in the monoclinic space group P2₁/n with cell parameters a = 15.0651(5), b = 6.3624(2), c = 15.3813(6) Å, β = 94.9690(10)°, Z = 4 and R = 0.0185. The hydroxide hydrate anion is coordinated to the ruthenium atoms of the identical cis-{RuNO(NH₃)₂Cl₂} fragments. The protonation of the starting cis-[RuNO(NH₃)₂(NO₂)₂OH] complex leads to the required coordinated aqua/hydroxide ratio if the specific amount of hydrochloric acid is used. The DFT calculations confirm the formation of the dimer structure in the gas phase. However, the presence of water molecules dramatically reduces the dimerization efficiency.     

Organometallic ruthenium complexes with thiosemicarbazone ligands: Synthesis,structure and cytotoxicity of [(η6-p-cymene)Ru(NS)Cl]+ (NS = 9-anthraldehyde thiosemicarbazones)

A series of half-sandwich arene ruthenium complexes containing bidentate thiosemicarbazone ligands have been synthesized and their biological activity investigated. The compounds have the general formula [(6-p-cymene)Ru(R-ATSC)Cl]X (ATSC = 9-anthraldehyde thiosemicarbazone and R = H, CH₃ and C₆H₅). The crystal structure of [(6-p-cymene) Ru(MeATSC)Cl]Cl have been determined and represents the first structurally characterized arene–ruthenium half-sandwich complex with a thiosemicarbazone ligand. The complexes show good cytotoxic profiles against MCF-7 and MDA-MB-231 (breast adenocarcinoma) as well as HCT 116 and HT-29 (colorectal carcinoma) cell lines.     

Self-assembly of an organo-palladium molecular basket that encapsulates cobalticarborane anion in water

Two [M₃L₃]^6 +-type organo-palladium(II) macrocyclic host molecules, {[(phen)Pd]₃(4,7-phen)₃}(NO₃)₆, 1·6NO₃⁻; {[(dtod-phen)Pd]₃(4,7-phen)₃}(NO₃)₆, 2·6NO₃⁻, (where M = (4,7-phen)Pd, (dtod-phen)Pd; 4,7-phen = 4,7-phenanthroline (L), phen = 1,10-phenanthroline, dtod-phen = 5,6-di(1′,4′,7′,10′-tetraoxododecanoxy)-1,10-phenanthroline), have been synthesized by metal-directed self-assembly in aqueous solution. These basket-shaped hosts bearing syn, syn, syn orientations and their anion complexes, have been fully characterized by ¹H NMR, cold-spray ionization mass spectrometry (CSI-MS) and in the case of basket-shaped host 1*PF₆⁻ by X-ray single-crystal diffraction analysis. On the basis of anion binding structure within the cavity of 1, the molecule basket 2 possessing a hydrophobic inner cavity expanded with hydrophilic polyethyleneglycol chains was successfully designed for encapsulating one giant anion [(C₂B₉H₁₁)₂Co]⁻ in water and the host–guest interaction was studied by ¹H NMR titration and CSI-MS.     

The crystal structure of 2′,6′-dichloro-4-dimethylaminoazobenzene

A monoazo dye, 2′,6′-dichloro-4-dimethylaminoazobenzene (C₁₄H₁₃Cl₂N₃) was synthesized and characterized by X-ray diffraction, IR, ¹H NMR, and elemental analysis. The title molecule crystallizes in the monoclinic system space group P2₁/c (#14), a = 10.782(1), b = 8.9610(9), c = 15.108(2) Å, β = 103.008(5)°, V = 1422.2(3) Å³, Z = 4. The title molecule is not planar and takes trans-geometry and the two phenyl rings are twisted around the central linkage in opposite directions. In the crystal, molecules are interacted through π⋯π interaction, forming ‘double chains’ along [1 −1 0]. The ‘double chains’ are extended along [001] through H-Bond C11–H6⋯Cl2, C5–H3⋯Cl1 forming double layers (110), which are in turn interacted by C3–H1⋯Cl1 H-Bond [010], forming crystals. The molecular geometry has been calculated using the ab initio restricted Hartree–Fock and density functional method (B3LYP) with 6-311G** basis set. The optimized geometric parameters obtained by two methods are similar and in good agreement with the experimental values.     

New trinuclear dendritic complexes with [Ru(tpy)(bpy)X]n + (X = Cl,H2O; n = 1, 2) for enhanced water oxidation and light-driven alcohol oxidation

A symmetric trinuclear ruthenium complex with [Ru(tpy)(bpy)(Cl)]⁺ (tpy = 2,2′:6′,2″-terpyridine; bpy = 2,2′-bipyridine) connected by 2,4,5-trimethylbenzene was easily prepared. The complex showed effective chemical water oxidation and light-driven oxidation activity of alcohols to corresponding aldehydes in water. When Cl⁻ is replaced by H₂O, the resulting complex exhibited over a twofold increase in O₂ evolution activity compared with its parent complex. Moreover, compared with equimolar ruthenium amounts of the mononuclear complex with the H₂O ligand, the trinuclear ruthenium complex with the conjugated ligand motif also displayed a two time increase in water oxidation activity.     

A three-dimensional zincic molybdenum (V) phosphate with helical channel: Synthesis,structure, and electrochemical properties

A new reduced zincic molybdophosphate, (H₂bpp)₃[Zn₃Mo₁₂^VO₂₄(OH)₆(H₂O)₂(HPO₄)₆(PO₄)₂]·2H₂O 1 (bpp = 1,3-bis(4-pyridyl)propane) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal space group I 41/a c d with a = 31.8033(4) Å, b = 31.8033(4) Å, c = 34.5593(8) Å, V = 34955.0(10) ų, and Z = 16 and exhibits a 4,6-connected 3-D framework with (3².8⁴)(3⁴.4².8³.9⁵.10) topology. The basic building blocks of [Zn(2)(Mo₆P₄)₂] are linked through [Zn(3)O₆] octahedra and [Zn(1)O₄] tetrahedra to construct 1-D chains along four different directions. Such 1-D chains are further connected by [Zn(1)O₄]²⁺ linkers to form a 3-D intricate framework with helical channels occupied by protonated bpp and water molecules. Additionally, the electrochemical property of the 1-CPE has been studied in detail.     

Synthesis,characterisation and cryomagnetic studies of a novel homonuclear Nd(III) Schiff base dimer

A novel homodinuclear complex [Nd^III(L)(NO₃)]₂ (1) has been synthesised [H₂L = N¹,N³- bis(salicylideneimino)diethylenetriamine, a pentadentate Schiff base with N₃O₂ donor set] and characterised with spectroscopic and micro-analytical techniques. Single crystal X-ray diffraction study reveals a centrosymmetric binuclear neutral entity [space group, P2₁/n; a = 12.911(5); b = 11.938(5); c = 13.960(5) Å; Z = 4] where Nd(III) metal centers are bridged together by two phenoxo oxygen atoms each coming from the two ligands. The most interesting fact is that two similar “salen” moieties of each ligand are behaving completely different in their coordination. In the doubly deprotonated ligand (L²⁻), one phenoxo oxygen is mono coordinated to the metal, whereas its immediate neighbour on the other end bridges the two Nd(III) centers. The distance between the Nd(III) centers is found to be 3.884(3) Å. Temperature dependence (2–300 K) magnetic susceptibility study suggests the presence of an antiferromagnetic interaction operating via two phenoxo bridges.     

Intraligand fluorescence of Zn(II) and Pt(II) complexes of pyridoxal thiosemicarbazone

Pyridoxal (vitamin B₆ aldehyde) thiosemicarbazone (B₆TSC) is deprotonated to its anion (B₆TSC – H⁺) in basic solution at pH = 9. It shows an intense green fluorescence with λ_max = 500 nm and a quantum yield of unity. Zn(II)(B₆TSC – H⁺)(acetate) displays an blue-green intraligand (B₆TSC) fluorescence of moderate intensity. The complex cation [Pt(II)(B₆TSC)Cl]⁺ is isolated as tetraphenylborate. In basic solution (pH = 9) this cation is deprotonated to the neutral complex [Pt(II)(B₆TSC – H⁺)Cl] which exhibits the same green intraligand fluorescence as the free anion (B₆TSC – H⁺)⁻. However, in the platinum complex this emission is much less intense. It is reduced to φ = 10^− 2.     

Blue-green photoluminescent 5- and 10-connected metal 5-(4′-carboxy-phenyl)tetrazolate coordination polymers

Hydrothermal reaction of Zn/Cd salts, NaN₃ and 4-cyanobenzoic acid via in situ [2 + 3] cycloaddition generated two blue-green photoluminescent coordination polymers [Zn(cptta)(H₂O)] (1) and [Cd(cptta)(H₂O)] (2) (H₂cptta = 5-(4′-carboxy-phenyl)tetrazole). When only metal ions are considered as nodes, 1 shows rare 5-connected Shubnikov plane topological type and 2 has unprecedented 10-connected {3¹².4²⁴.5⁹} topological type.     

Synthesis,crystal structure and luminescent properties of new tris-β-diketonate Eu(III) complex with thiadiazolophenanthroline derivative ligand

Herein we describe the synthesis, characterization and spectroscopic properties of the complex tris-(thenoyltrifluoroacetonate)([1, 2, 5]thiadiazolo[3, 4-f][1,10]phenanthroline) europium(III) acetonitrile solvate, [Eu(TTA)₃ TDPHEN] 1.5CH₃CN, where TTA = 2-thenoyl trifluoroacetone and TDPHEN = [1, 2, 5]thiadiazolo[3, 4-f][1, 10] phenanthroline. X-ray crystallography reveals that it is an eight-coordinate Eu(III) complex containing three β-diketonate chelates and one N,N′-bidentate ligand, [1, 2, 5] thiadiazolo[3, 4-f][1, 10] phenanthroline. The excitation at 340 nm of the europium complex in a solution of acetonitrile, and at room-temperature, showed the typical Eu(III) red emission as a sharp band at 611 nm, characteristic of Eu(III) due to the transition ⁵D₀ → ⁷F₂. This complex also showed red emission in the solid state phase (λ_em = 612 nm).