Na Zhang

pH-Dependent Ag(I) coordination architectures constructed from 4-cyanopyridine and phthalic acid: from discrete structure to 2D sheet

Four mixed-ligand Ag(I) coordination complexes (CCs), namely, [Ag(cnpy)2(Hpta)] (1), [Ag2(cnpy)2(Hpta)2] (2), [Ag4(cnpy)2(pta)2(H2O)]n (3) and [Ag2(inta)2(pta)·3H2O]n (4), (cnpy = 4–cyanopyridine, H2pta = phthalic acid, inta = isonicotinamide) have been synthesized through a one-pot ultrasonic reaction of silver(I) oxide, cnpy and H2pta under different pH values and structurally characterized. Complexes 1 and 2 formed at lower pH values (5.0 for 1 and 6.9 for 2) exhibit zero-dimensional (0D) mononuclear and tetranuclear motifs, respectively. Reaction at pH = 8.8 leads to a two-dimensional (2D) structure of 3 in which completely deprotonated H2pta shows two kinds of coordination modes: μ5-η1:η1:η1:η3 and μ6-η1:η1:η1:η3. A further increase of the pH value to 9.4 results in the in situhydrolysis of cnpy and produces complex 4 as a one-dimensional (1D) chain structure. Of particular interest, a well-resolved chair-like centrosymmetric hexamer water cluster, (H2O)6, which is stabilized by 1D chains through six dangling hydrogen bonds, exists in 4. Comparing the experimental results, it is comprehensible that the pH value plays a crucial role in the formation of the resulting structures. Additionally, results about IR spectra, thermogravimetric curves and photoluminescence spectra were discussed.

Synthesis, characterization and property of a mixed-valent AgI/AgII coordination polymer

A novel mixed-valent Ag(I)/Ag(II) coordination polymer {[Ag(I)(2)Ag(II)(0.5)(SO(4))(HSO(4))(pyz)(2.5)]·H(2)O}(n) (1, pyz = pyrazine) was synthesized and characterized. The results show it presents semiconducting and photoluminescent properties.

Self-assembly, thermal stability and photoluminescence of two mixed-ligand silver(I) networks via 2D → 2D and 2D → 3D parallel interpenetration of (4,4) nets

Two mixed-ligand silver(I) coordination polymers (CPs) [Ag2(dmapym)2(suc)·H2O]n (1) and [Ag2(dmapym)2(bdc)·2H2O]n (2), (dmapym = 2-amino-4,6-dimethylpyrimidine, H2suc = succinic acid, H2bdc = 1,3-benzenedicarboxylic acid), were synthesized and characterized. The structure of 1 presents an argentophilic interaction enhanced 2-crossing [2]-catenane motif formed between pairs of parallel interpenetrating 2D 44-sql nets. For 2, as the dicarboxylate changes from flexible H2suc to rigid V-shaped H2bdc, each highly undulated 2D 44-sql net was penetrated in parallel by the two nearest neighbouring ones and thus the overall 2D → 3D network is formed. The geometries and flexibility of dicarboxylates influence the coordination environments of metal ions and arrangement of ligands and thus determine the structures of the CPs. The photoluminescent and thermal properties of 1 and 2 have also been investigated.

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.

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.

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.

Bis[diamminesilver(I)] 5-nitro­iso­phthalate monohydrate

In the title compound, [Ag(NH3)2]2(C8H3NO6)·H2O, the cations have an almost linear coordination geometry with two ammine ligands and interact with the water molecules [Ag⋯Owater = 2.725 (4) and 2.985 (4) Å]. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds, combined with weak (lone pair)⋯π [O⋯centroid distance = 3.401 (4) Å] and π–π stacking [centroid–centroid distance = 3.975 (3) Å] interactions, stabilize the three-dimensional supramolecular network.

CCDC 823092: Experimental Crystal Structure Determination

Related Article: Di Sun, Fu-Jing Liu, Hong-Jun Hao, Yun-Hua Li, Na Zhang, Rong-Bin Huang, Lan-Sun Zheng|2011|CrystEngComm|13|5661|doi:10.1039/c1ce05622k

CCDC 823094: Experimental Crystal Structure Determination

Related Article: Di Sun, Fu-Jing Liu, Hong-Jun Hao, Yun-Hua Li, Na Zhang, Rong-Bin Huang, Lan-Sun Zheng|2011|CrystEngComm|13|5661|doi:10.1039/c1ce05622k

Self-assembly of a Novel Three-dimensional Silver(I) Supramolecular Framework from Cationic Chains and Anionic Sheets

A new three-dimensional (3D) supramolecular framework, [Ag2(bipy)2(bdc)·4H2O]n 1, has been synthesized by the ultrasonic reaction of Ag2O, bipy and H2bdc (H2bdc = 1,4-benzenedicarboxylic acid; bipy = 4,4’-bipyridine) at room temperature. It exhibits a new 3D supramolecular framework which is built from cationic Ag-bipy chains and anionic bdc-H2O sheets through hydrogen bonds, π · · ·π stacking and C-H· · ·π interactions. Additionally, the photoluminescent and thermal properties of 1 were investigated. Graphical Abstract Self-assembly of a Novel Three-dimensional Silver(I) Supramolecular Framework from Cationic Chains and Anionic Sheets