Hua-Xin Zhang

Chair-form [Ag2(1,2-bimb)2]2+ in silver(I) complexes containing the ditopic ligand 1,2-bis(1-imidazolylmethyl)benzene (1,2-bimb)

Abstract The ditopic ligand 1,2-bis(1-imidazolylmethyl)benzene (1,2-bimb) and its silver(I) complexes [Ag2(1,2-bimb)2](PF6)2 (1) and {[Ag2(1,2-bimb)2]2(SbF6)4}n (2) were prepared and their structures characterized by X-ray crystallography. Both complexes contain the chair-form unit [Ag2(1,2-bimb)2]2+ with Ag(I) linearly coordinated by NIm (Im=1-imidazolyl) from the Im groups of two 1,2-bimb. However, the [Ag2(1,2-bimb)2]2+ units are positioned differently in forming 1D infinite chains through weak argentophilic interactions: linear chains in 1 with the units oriented in same direction are formed via Ag⋯π interactions, while polymeric chains constructed via Ag⋯Ag interactions in 2 are observed with the units arranged in alternate directions. Differences in supramolecular structures may be a result of different size of the anions.

Modulation of the coordination environment of silver(I) in bis(diphenylphosphino)methane complexes by selection of heterocyclic thiolato ligands

Abstract Complexes [Ag 4 (mbi: N , N , S )(dppm) 4 ][BF 4 ] 2 ( 1 ), [Ag 4 (mpym: N , S ) 2 (dppm) 4 ][BF 4 ] 2 ( 2 ) and [Ag 2 (mnic: O , S )(dppm) 2 ] 2 ( 3 ) with Ag(I) in varied coordination geometries were obtained from the reactions of AgBF 4 and the heterocyclic thiolato ligands 2-mercaptobenzimidazole (H 2 mbi), 2-mercaptopyrimidine (Hmpym) and 2-mercaptonicotinic acid (H 2 mnic), respectively, with the participation of bis(diphenylphosphino)methane (dppm). The products have been characterized by elemental analyses, IR, 1 H and 31 P NMR. X-ray crystallographic analyses showed that the structures and the coordination modes are obviously modulated by the thiolato ligands used. With the diazothiolates mbi 2− and mpym − , both 1 and 2 contain two closed [Ag 2 (dppm) 2 ] units connected by the thiolates. When the carboxyl-substituted thiopyridine (H 2 mnic) was used in 3 , a new coordination mode was observed in which the thiolate mnic 2− provided an μ 3 -S to the core of M 4 (dppm) 4 resulting in a neutral complex in which the four Ag atoms are connected by four dppm ligands head-to-tail .

Helical complexes from the self-assembly of silver salts and the polydentate thioether α,α′-bis(8-thioquinoline)-m-xylene

Abstract The self assembly of AgX with the sulfur-containing multidentate ligand α,α′-bis(8-thioquinoline)-m-xylene (m-XYTQ) affords two isomorphous complexes [Ag(m-XYTQ)]nXn (X=ClO4 1; X=BF4 2). Single crystal X-ray analyses revealed the complexes to contain linear cationic chains of [Ag(m-XYTQ)]nn+ in helical arrangement and the anions are discrete. Intramolecular π⋯π stackings pack the asymmetric units [Ag(m-XYTQ)] in shelves-like arrays while interchain π⋯π interactions between racemic chains constructed the 2D network. The key to helix formation is the folding at the sulfur sites of the spacer xylylene in the ligand. The complexes were also characterized by 1H NMR and IR.

Cyano-bridged extended heteronuclear supramolecular architectures with hexacyanoferrates(II) as building blocks

Abstract Two cyano-bridged heteronuclear coordination polymers [{Cu(bipn)} 3 Fe(CN) 6 ] n (ClO 4 ) 2 n ·4 n H 2 O (bipn=bis(3-aminopropyl)amine) ( 1 ) and [{Cd(tet)} 2 Fe(CN) 6 ] n ·3 n H 2 O (tet=triethylenetetramine) ( 2 ) were synthesized and their structures determined. Both complexes were obtained from the assembly reactions of [ML n ] 2+ (M=Cu, Cd; n =1, 2) and [Fe(CN) 6 ] 4− in aqueous solutions. Complex 1 exhibits a honeycomb structure with twisty rings formed by Cu(II), Fe(II), and cyanides. The anions ClO 4 − weakly coordinate to Cu(II) and form hydrogen bonds with amino groups of bipn, while water molecules link to the 2D network via hydrogen bonds. In complex 2 , the neutral polymer [{Cd(tet)} 2 Fe(CN) 6 ] n forms zigzag chains. The water molecules insert between chains and pull them together to form a layered structure via a series of interchain hydrogen bonds. Thermal analyses over the temperature range 30–700°C show both complexes decompose completely above 460°C.

Coordination-directed assembly of trigonal and tetragonal molecular boxes encapsulating anionic guests

M2L3 and M2L4 box-like complexes {[Ag2(pbbimb)3][CF3SO3]21 and [Cu2(mbbimb)4][ClO4]42} with respective S3 and S4 symmetry, in which anionic molecular guests are accommodated, have been synthesized and structurally characterized.

Chair‐ and Boat‐Configurations of Silver(I) Complexes of Ditopic Ligand Involving Benzimidazolyl Substituents

The ditopic ligand 1, 2-bis(benzimidazol-1-ylmethyl)benzene (L1) as well as its silver(I) complexes [Ag2L12(CF3CO2)2] (1) and [Ag2L12](CF3SO3)2 · (L1) · 2H2O · 0.5C2H5OH (2) were prepared and structures characterized by X-ray crystallography. The AgI atoms in 1 are trigonally coordinated by two NBIm atoms from the arms of L1 and by one O atom of the anion CF3CO2—, while those in 2 are only linearly ligated by NBIm. Different silver salts of CF3CO2— and CF3SO3— lead to different configurations of the dimeric unit [Ag2L12]2+: chair-form in (1) but boat-form in (2). The discrete molecules in both 1 and 2 are assembled into network structures through face-to-face π · · · π stacking and edge-to-face C—H · · · π interactions in the crystalline state, as well as N—H · · · O and C—H · · · O hydrogen bonds. Solution 1H NMR studies showed the formation of one sole species in solution or a rapid equilibrium was established on the NMR time scale at room temperature. Sessel- und Boot-Konfigurationen von Silber(I)-Komplexen des ditopen Liganden mit Benzimidazolylsubstituenten Der ditope Ligand 1, 2-Bis(benzimidazol-1-ylmethyl)benzen (L1) und seine Silber(I)-Komplexe [Ag2L12(CF3CO2)2] (1) und [Ag2L12](CF3SO3)2 · (L1) · 2H2O · 0.5C2H5OH (2) wurden dargestellt und durch Rontgenstrukturanalysen charakterisiert. Die Silber(I)-Atome in 1 sind trigonal von zwei NBim-Atomen der Arme von L1 und von einem O-Atom des CF3CO2—-Anions koordiniert, wahrend sie in 2 nur linear von NBim koordiniert werden. Die verschiedenen Silbersalze von CF3COO2— bzw. CF3SO3— fuhren zu unterschiedlichen Koonfigurationen der dimeren [Ag2L12]2+-Einheit: Sessel-Form in 1 und Boot-Form in 2. Im kristallinen Zustand sind die isolierten Molekule sowohl von 1 wie von 2 in Netzwerkstrukturen angeordnet mit Flache-zu-Flache-π · · · π-Stapelung und Kante-zu-Flache-C—H · · · π-Wechselwirkung sowie N—H · · · O und C—H · · · O-Wasserstoff-Bruckenbindungen. 1H-NMR-Untersuchungen in Losung zeigen die Bildung von nur einer Spezies oder einer schnellen Gleichgewichtseinstellung in Losung bei Raumtemperatur.

Assembly of a novel cyclic dimer encapsulating PF-6 into the brick wall network

Abstract The cyclic silver (I) dimer [Ag(m-bitmb)]2(PF6)2·2MeCN of 1,3-bis(imidazolylmethyl)-2,4,6-trimethylbenzene (m-bitmb) was prepared and its structure characterized by X-ray crystallography. An PF−6 anion is encapsulated within the macrocyclic cation [Ag(m-bitmb)]22+ with weak Ag⋯F and CH⋯F interactions. Two types of intermolecular π–π interactions lead to a brick wall network.

A non-interpenetrating 2D coordination polymer from a (CH2)8 spacer-based highly flexible linear ligand and AgCF3CO2Electronic supplementary information (ESI) available: 1H NMR spectra and data for C8TQ and complex 1 and the 3-D structure of complex 1. See http://www.rsc.org/suppdata/nj/b3/b301777j

Reaction of a (CH2)8 spacer-based ligand, 1,8-bis(8-thioquinolyl)octane (C8TQ), with AgCF3CO2 affords a designed non-interpenetrating 2D brick-wall coordination polymer [Ag2(C8TQ)(CF3CO2)2]n, composed of thio-bridged helical chains racemically aligned and further connected by the (CH2)8 spacers, while weak F⋯F interactions between ligated CF3CO2− fabricate the 3D supramolecular architecture.

A trinuclear nickel(II) complex with alternating square-planar and octahedral geometries. Synthesis, crystal structure and magnetic properties of [Ni3(oxen)2(en)][ClO4]2

Abstract The reaction of Ni(oxen)[oxen = N , N ′-bis(2-aminoethyl)oxamido dianion], NiCl 2 and the disodium salt of EDTA (ethylenediamine tetraacetic acid) in 1:1:1 molar ratio gave the trinuclear complex [Ni 3 (oxen) 2 (en)][ClO 4 ] 2 (en = 1,2-ethylenediamine), where en came from the partial decomposition of oxen. The complex exhibits a curved Ni 3 metal arrangement with the angle Ni(2)Ni(1)Ni(2a) of 119.0°. The structure consists of a Ni 3 II unit with three nickel(II) atoms chelated and bridged by two oxamidato (oxen) groups in cis -conformation. The central nickel atom has a distorted octahedral geometry whereas the two on the sides have square-planar surroundings. The complex is paramagnetic and its magnetic behaviour can be interpreted by single-ion anisotropy with D = 5.22 cm −1 and m s = 0 singlet ground state.

2D hexagonal grids assembled into 3D nets via Ag···Ag interactions

AbstractA three-dimensional coordination polymer [Ni(en)2Ag3(CN)5]n (en = 1,2-diaminoethane) was synthesized and characterized by X-ray crystallography. It crystallizes in the triclinic space group