Geng-Geng Luo

catena-Poly[[[(iminodiacetato-κO)silver(I)]-μ3-2-aminopyrimidine-κ3N1:N2:N3] monohydrate]: a one-dimensional silver(I) coordination polymer with mixed ligands

The title compound, {[Ag(C4H6NO4)(C4H5N3)].H2O}n, was synthesized by the reaction of silver(I) nitrate with 2-aminopyrimidine and iminodiacetic acid. X-ray analysis reveals that the crystal structure contains a one-dimensional ladder-like Ag(I) coordination polymer and that N-H...O and O-H...O hydrogen bonding results in a three-dimensional network. The Ag(I) centre is four-coordinated by three N atoms from three different 2-aminopyrimidine ligands and one O atom from one iminodiacetate ligand. Comparison of the structural features with previous findings suggests that the existence of a second ligand plays an important role in the construction of such polymer frameworks.

Discovery of polymorphism-dependent emission for crystalline boron-dipyrromethene dye

4-Methoxycarbonylphenyl-substituted BODIPY (boron-dipyrromethene) dye gives, in the solid state, three polymorphs. In spite of the absence of any strong intermolecular interactions in all crystalline forms, the three polymorphs show different photoluminescence properties. This behavior highlights the importance of molecular arrangements of the BODIPY moieties in the crystalline state in perturbing their photophysical properties.

Direct observation of conformational change of adipate dianions encapsulated in water clusters

Two novel hydrated adipate dianions including (adip)aaa·(H2O)16 and (adip)gag·(H2O)20 (adip = dianion of adipic acid, aaa = anti–anti–anti and gag = gauche–anti–gauche) were observed in two silver-based cationic hosts. They not only reveal the precise arrangement of water clusters around the carboxylate groups and aliphatic chains of adipate dianions, but show the conformational change of adipate dianions in water clusters, for the first time.

A hybrid carboxylate-water decamer with a discrete octameric water moiety self-assembled in a 2D copper(II) coordination polymer

An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon (1r,4r)-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu(II) mixed-ligand coordination polymer, {[Cu2(bpp)2(H2O)2(bpda)2]·6H2O}n (1) (bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2′-biphenyldicarboxylic acid). The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2− are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly (H2O)10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.

Octanuclear Ni(II) cubes based on halogen-substituted pyrazolates: synthesis, structure, electrochemistry and magnetism

The employment of halogen-substituted pyrazole ligands in nickel(II) clusters afforded three anionic Ni(II) cubes, (HNEt3)2[Ni8(Xpz)12(OH)6] (X = Cl, 1·2CH3CN; X = Br, 2·2CH3CN; X = I, 3·12CH3CN; pz = pyrazolate). Clusters 1–3 are isolated as dianionic compounds which have similar cube geometry with each vertex occupied by a Ni(II) atom and eight μ4-OH− capped on eight square faces. The Xpz ligands adopt a bidentate mode to bind paired Ni(II) atoms on the edge of the cube. Interestingly, the three Ni8 cubes have similar symmetry, size and shape but pack together to form different lattice symmetry, which should be dictated by the halogen-related supramolecular interactions (C–X⋯H, C–X⋯π and X⋯X halogen bonding) in different crystals. The electrochemistry of 1–3 showed a Ni(II)/Ni(I) redox couple with E1/2 at ca. 900 mV and the oxidization potential order is 1 > 3 > 2 depending on the halogen substituents. 1–3 exhibit excellent electrocatalytic performances toward the oxidation of nitrite. The different packing of Ni8 cubes in 1–3 also has an important influence on their magnetic behaviors. Complex 2 showed antiferromagnetic couplings between the Ni(II) ions within the cubes, whereas 1 and 3 exclusively exhibited mixed ferromagnetic and antiferromagnetic properties, leading to frustration and typical spin glass behavior.

Silver–Sulfur Hybrid Supertetrahedral Clusters: The Hitherto Missing Members in the Metal–Chalcogenide Tetrahedral Clusters

The synthesis of Group 11 metal chalcogenide supertetrahedral clusters (SCs) still remains a great challenge mainly due to the high tendency of metal aggregation through metallophilicity and global charge balance. Demonstrated herein are the preparation, crystallographic characterization, and optical properties of two stable silver-sulfur SCs through ligand-control; one as a discrete zero-dimensional (0D) V3,4-type cluster and the other as a one-dimensional (1D) zigzag chain extended by alternating V3,2-type clusters. The notation Vn,m (where n is the number of metal layers, and m is the number of vacant corners) is used to describe a new series of vacant-corner SCs, which can be derived from the regular Tn clusters. The existence of vacant-corner-type SCs may be ascribed to the low valence and tri-coordinated environment of silver ions. These are the first representatives of structurally determined silver-sulfur tetrahedral clusters thus far. This work enriches the coinage-metal chalcogenide tetrahedral cluster portfolio, discovers vacant-corner SCs present in silver-sulfur hybrid tetrahedral clusters, and provides effective means for further development of Group 11 coinage-metal chalcogenide SCs.

Two novel silver(I) coordination polymers: poly[(μ2‐2‐aminopyrimidine‐κ2N1:N3)bis(μ3‐thiocyanato‐κ3S:S:S)disilver(I)] and poly[(2‐amino‐4,6‐dimethylpyrimidine‐κN)(μ3‐thiocyanato‐κ3N:S:S)silver(I)]

2-Aminopyrimidine (L1) and 2-amino-4,6-dimethylpyrimidine (L2) have been used to create the two novel title complexes, [Ag2(NCS)2(C4H5N3)]n, (I), and [Ag(NCS)(C6H9N3)]n, (II). The structures of complexes (I) and (II) are mainly directed by the steric properties of the ligands. In (I), the L1 ligand is bisected by a twofold rotation axis running through the amine N atom and opposite C atoms of the pyrimidine ring. The thiocyanate anion adopts the rare mu3-kappa3S coordination mode to link three tetrahedrally coordinated Ag(I) ions into a two-dimensional honeycomb-like 6(3) net. The L1 ligands further extend the two-dimensional sheet to form a three-dimensional framework by bridging Ag(I) ions in adjacent layers. In (II), with three formula units in the asymmetric unit, the L2 ligand bonds to a single Ag(I) ion in a monodentate fashion, while the thiocyanate anions adopt a mu3-kappa1N,kappa2S coordination mode to link the AgL2 subunits to form two-dimensional sheets. These layers are linked by N-H...N hydrogen bonds between the noncoordinated amino H atoms and both thiocyanate and pyrimidine N atoms.

Synthesis, crystal structure and optical properties of [Ag(UO2)3(OAc)9][Zn(H2O)4(CH3CH2OH)2]: A novel compound containing closed-shell 3d10, 4d10 and 5d10 metal ions

[Ag(UO2)3 (OAc)9][Zn(H2O)4(CH3CH2OH)2] (, OAc = CH3COO-) crystallized from an ethanol solution and its structure was determined by IR spectroscopy, elemental analysis, 1H NMR, 13C NMR and X-ray crystallography; it is composed of [Zn(H2O)4(CH3CH2OH)2]2+ cations and [Ag(UO2)3(OAc)9]2- anions in which triuranyl [(UO2)(OAc)3]3 clusters are linked by the Ag ion.

A self-assembled (H 2 O) 20 (CH 3 OH) 4 binary cluster containing a grail-shaped hexadecameric water cluster trapped in the cavity of a metal-ligand hybrid

A discrete centrosymmetric (H2O)20(CH3OH)4 binary cluster was confined in the cavity of a metal-ligand hybrid [Ag4(bpda)2(bpp)4·14H2O·2CH3OH]n (1) (where bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2′-biphenyldicarboxylic acid). The novel mixed water-methanol cluster consists of one grail-shaped hexadecameric cluster, four dangling water and four hanging methanol molecules. The (H2O)16 cluster is composed of two pairs of edge-sharing (H2O)5 rings attached to one (H2O)4 core with twenty hydrogen bonds. Alternatively, the (H2O)16 cluster is structurally similar to a complicated hydrocarbon generated by undergoing [2+2] cycloaddition of 1,2,3,4,5,6-hexahydropentalene, which reveals the resemblance between water clusters and organic compounds.

Poly[bis(μ2-2-aminopyrazine-κ2N1:N4)(μ2-nitrato-κ2O:O)(nitrato-κ2O,O′)disilver(I)]: an achiral two-dimensional coordination polymer forming chiral crystals

The solution reaction of AgNO(3) and 2-aminopyrazine (apyz) in a 1:1 ratio gives rise to the title compound, [Ag(2)(NO(3))(2)(C(4)H(5)N(3))(2)](n), (I), which possesses a chiral crystal structure. In (I), both of the crystallographically independent Ag(I) cations are coordinated in tetrahedral geometries by two N atoms from two apyz ligands and two O atoms from nitrate anions; however, the Ag(I) centers show two different coordination environments in which one is coordinated by two O atoms from two different symmetry-related nitrate anions and the second is coordinated by two O atoms from a single nitrate anion. The crystal structure consists of one-dimensional Ag(I)-apyz chains, which are further extended by mu(2)-kappa(2)O:O nitrate anions into a two-dimensional (4,4) sheet. N-H...O and C(apyz)-H...O hydrogen bonds connect neighboring sheets to form a three-dimensional supramolecular framework.