The linkage of Li(I) and Ca(II) ions to the eight-coordinate [Cu(η-Me3NCH2CO2-O,O′)4] core results in the new complexes [LiCu(bet)4]n(ClO4)3n (2) and [CaCu(bet)4(NO3)2(H2O)]2[Ca(NO3)4(H2O)]2 (3) (bet = Me3N⁺CH2CO2^-). X-ray structural analysis has revealed that 2 comprises an infinite cationic column with each pair of the eightcoordinate cores bridged by a Li(I) atom, featuring the shortest weak Cu-O(carboxylate) bond [2.705(5) Å] among its type, whereas 3 contains a heterodinuclear Cu-Ca cation consolidated by an uncommmon triple carboxylato-O,O′ bridge with the Cu(II) atom surrounded by the four chelate groups in a three-up/one-down eight-coordinate arrangement. The dinuclear anion in 3 contains three kinds of nitrato ligands acting in bridging, bidentate chelate, and unidentate modes. Crystal data for 2 (21 °C): tetragonal, space group P42m (No. 111), a = 12.096(3) Å, c = 6.2330(7) Å, V= 911.8(3) ų, Z = 1; R = 0.051 (Rw = 0.060) for 613 data with I> 1.5 σ(I). Crystal data for 3 (21 °C): monoclinic, space group P21/n (No. 14), a = 12.105(2) Å,b = 22.796(9) Å, c = 15.572(4) Å, β = 90.63(1)°, V = 4297(2) ų, Z = 2; R = 0.069 (Rw = 0.053) for 4690 data with I > 3σ(I). © 1994, American Chemical Society. All rights reserved.

Chen Xiao-Ming;Mak Thomas C. W.

Inorganic Chemistry

1994

The crystal and molecular structure of [Cu(BET)4]·(NO3)2(BET= Me3N⁺CH2COO^-) has been established by X-ray crystallography. The complex consists of discrete [Cu(BET)4]²⁺and nitrate anions, with the copper(II) atom eight-coordinated by four short CuO(carboxy) bonds [1.948(3) Å] and four long CuO(carboxy) bonds [2.833(4) Å] in a distorted dodecahedral 4̄2m (D2d) environment. © 1991.

Chen Xiao-Ming;Mak Thomas C.W.

Polyhedron

1991

In the presence of guest 2,4′-bpy molecules or under acidic conditions, three compounds, [Cd(4,4′-bpy)2(H2O)2]- (ClO4)2·(2,4′-bpy)2·(H 2O (1), [Zn(4,4′-bpy)2(H2O)2](ClO 4)2·(2,4′-bpy)2·H 2O (2), and [Cu(4,4′-bpy)2(H2O)2](ClO 4)4·(4,4′- H2bpy) (3), were obtained from the reactions of the metal salts and 4,4′-bpy in an EtOH-H2O mixture. 1 has a 2-D square-grid network structure, crystallizing in the monoclinic space group P2/n, with a = 13.231(3) Å, b = 11.669(2) Å, c = 15.019(3) Å, β= 112.82(3)°, Z = 2; 2 is isomorphous with 1, crystallizing in the monoclinic space group P2/n, with a = 13.150(3) Å, b = 11.368(2) Å, c = 14.745(3) Å, β = 110.60(3)°, Z = 2. The square grids superpose on each other into a channel structure, in which each layer consists of two pairs of shared edges, perfectly square-planar with an M^II ion and a 4,4′-bpy at each corner and side, respectively. The square cavity has dimensions of 11.669(2) × 11.788(2) and 11.368(2) × 11.488(2) Åfor 1 and 2, respectively. Every two guest 2,4′-bpy molecules are clathrated in each hydrophobic host cavity and are further stabilized by π-π stacking and hydrogen bonding interactions. The NMR spectra clearly confirm that both 1 and 2 contain 4,4′-bpy and 2,4′-bpy molecules in a 1:1 ratio, which have stacking interaction with each other in the solution. 3 crystallizes in the orthorhombic space group Ibam, with a = 11.1283(5) Å, b = 15.5927(8) Å, c = 22.3178(11) Å, Z = 4. 3 is made up of two-dimensional square [Cu4(4,4′-bpy)4] grids, where the square cavity has dimensions of 11.13 × 11.16 Å. Each [4,4′-H2bpy]²⁺ cation is clathrated in a square cavity and stacks with one pair of opposite edges of the host square cavity in an offset fashion with the face-to-face distance of ca. 3.95 Å. Within each cavity, the [4,4′-H2bpy]²⁺ cation forms twin three-center hydrogen bonds with two pairs of ClO4^- anions. The results suggest that, the guest 2,4′-bpy molecules and protonated [4,4′-H2bpy]²⁺ cations present in the reaction systems serve as structure-directing templates in the formation of the crystal structures and exclude self-inclusion of the networks having larger square cavities.

Tong Ming-Liang;Ye Bao-Hui;Chen Xiao-Ming;Cai Ji-Wen;Ng Seik Weng

Inorganic Chemistry

1998

Chen Xiao-Ming;Wu Yu-Luan;Yang Yan-Sheng;Aubin Sheila M. J.;Hendrickson David N.;Mak Thomas C. W.

Journal of the American Chemical Society

1995

The compound Cd[C3N2H11]2[V8O 20] was synthesized from the hydrothermal reactions of V2O5, CdSO4, 1,2-diaminopropane (enMe) and water in the molar ratio 1:1:2.2:223. Its structure has been determined by single-crystal X-ray diffraction. This compound has an open three-dimensional framework structure consisting of [V8O20]^4- layers, composed of equal numbers of VO4 tetrahedra and VO5 pyramids connected by both corner and edge sharing. The Cd[enMeH]2⁴⁺ complex occupies the interlayer space and connects with the vanadium oxide layers through four Cd-O bonds. This arrangement gives one-dimensional channels with 10-membered rings along the c axis. © The Royal Society of Chemistry 2000.

Zhang Lirong;Shi Zhan;Yang Guoyu;Feng Shouhua;Chen Xiaoming

Journal of the Chemical Society Dalton Transactions

2000

A new monomeric manganese(II) complex with 2,2′-bipyridine (bpy), [Mn(bpy)3-] (ClO4)2·0.5(bpy), has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space group P1̄ with a = 9.535(2), b = 13.194(3), c = 14.854(3) Å, α = 96.50(3), β = 107.26(3), γ = 91.19(3)°, V = 1770.2(7) ų, and Z = 2. The structure comprises discrete [Mn(bpy)3]²⁺ cations in which the metal atom is coordinated in a highly distorted octahedral environment by three chelate bpy ligands [Mn-N = 2.229(3) - 2.289(2) Å]. The solvate bpy molecule and a pair of coordinated bpy ligands each from the adjacent cations are arranged in an off-set fashion, showing significant intermolecular stacking interaction with close interplanar contacts of ca. 3.47 Å.

Yu Xiao-Lan;Tong Ye-Xiang;Chen Xiao-Ming;Mak Thomas C. W.

Journal of Chemical Crystallography

1997

Synthesis, crystal structures, and magnetic properties of two types of carboxylate-bridged Cu^II2Ln^III2 complexes, formulated as [Cu2Ln2(bet)10(H2O) 8](ClO4)10·2H2 (1; Ln^III = La^III, Ce^III, or Gd^III; bet = betaine) and [Cu2Ln2- (bet)12(ClO4)2](ClO4)8 (2; Ln^III = Gd^III or Sm^III), have been described. 1·La features a carboxylate-bridged, tetranuclear [Cu2La2(bet)10(H2O) 8]¹⁰⁺ cation, crystallizing in the triclinic space group P1̄, with a = 12.778(4) Å, b = 15.553(5) Å, c = 16.041(5) Å, α = 110.18(2)°, β= 100.72(2)°, γ = 105.03(2)°, and Z = 1; 1·Ce is isomorphous with 1·La, crystallizing in the triclinic space group P1̄, with a = 12.730(2) Å, b = 15.489(2) Å, c = 15.987(3) Å, α = 110.28(1)°, β= 100.70(1)°, γ = 105.00(2)°, and Z = 1. In both 1·La and 1·Ce, a Cu^II atom is quadruply bridged to a Ln^III atom by the μ2-carboxylate groups into a dinuclear subunit, and a pair of such dinuclear subunits is bridged by two carboxylate groups to form a tetranuclear cation. In the tetranuclear cation, each Cu^II atom is coordinated in a square pyramid by four carboxy oxygen atoms at the basal positions and by one aqua ligand at the apical position whereas each Ln^III atom is coordinated in a monocapped square antiprism by six carboxy oxygen atoms and three aqua ligands. 1·Gd has been characterized to be an analogue of 1·La. 2·Gd consists of a different tetranuclear [Cu2Gd2(bet)12(ClO4) 2]⁸⁺ cation, crystallizing in the orthorhombic space group Pmcb with a = 12.323(3) Å, b = 17.119(4) Å, c = 26.381(7) Å, and Z = 2; 2·Sm is isomorphous with 2·Gd, crystallizing in the orthorhombic space group Pmcb, with a =12.496(2) Å, b = 17.378(3) Å, c = 26.767(5) Å, and Z = 2. In both 2·Gd and 2·Sm, a pair of dinuclear subunits analogous to those in 1·La are linked by a quadruple carboxylate bridge between the pair of Ln^III atoms into a tetranuclear cation, where the apical ligand of the square pyramid about each Cu^II atom is a perchlorate and each Ln^III atom is coordinated in a square antiprism by eight carboxy oxygen atoms. The magnetic behavior of these complexes obeys the Curie-Weiss law. showing very weak antiferromagnetic interaction in the solid. Therefore, it may be concluded that shielding of the 4f electrons by the outer shell electrons very effectively precludes significant coupling interactions between the lanthanoid 4f electrons and copper 3d electrons in a carboxylate-bridged system.

Chen Xiao-Ming;Wu Yu-Luan;Yang Yang-Yi;Aubin Sheila M. J.;Hendrickson David N.

Inorganic Chemistry

1998

A mixed-ligand monomeric complex [Zn(bpy)2(MeCO2)](ClO4)·H2O (bpy = 2,2′-bipyridine) has been prepared and characterized by X-ray crystallography. The zinc(II) atom is surrounded in a highly distorted octahedral N4O2 environment with ZnN bonds at 2.121(5)-2.131(4) Å and ZnO bonds at 2.155(4)-2.246(4) Å. The acetato group forms an unusual out-of-plane hydrogen bond with the lattice water molecule. © 1994.

Chen Xiao-Ming;Xu Zhi-Tao;Mak Thomas C.W.

Polyhedron

1994

Two dimeric lanthanoid (III) complexes, [Ln2( bpy )2( pybet )4(H2O)4] ( bpy )3(ClO4)6.H2O ( bpy = 2, 2′-bipyridine, pybet = pyridinioacetate, and Ln Eu and Tb), have been prepared and characterized by X-ray crystallography. The complexes are isostructural, each comprising a quadruply carboxylato -bridged, centrosymmetrical dimeric cation, six perchlorate anions, three uncoordinated bpy molecules and a lattice water molecule. Each Ln ion is surrounded in a distorted square-antiprismatic environment by four carboxylato oxygen atoms, two nitrogen atoms of the bidentate bpy ligand and two aqua ligands. The Ln-O bond lengths range from 2.33 to 2.44 Â, and Ln-N bond lengths from 2.55 to 2.64 Â. The uncoordinated bpy molecules are linked to the aqua ligands by hydrogen bonds. © 1995 ASEG.

Chen Xiao-Ming;Wu Yu-Lua;Yan Yan-Sheng

Australian Journal of Chemistry

1995

The title polymeric complex, [Cd(SCN) 2 (C 3 H 4 N 2 ) 2 ] n , exhibits an infinite chain structure in which each pair of Cd atoms is bridged by two η-1,3-SCN ^- groups. The unique Cd atom lies on an inversion centre and the coordination sphere is completed by two imidazole N atoms to form a CdS 2 N 4 octahedron. The polymeric chains are further extended into two-dimensional sheets via N - H⋯S hydrogen bonds between the uncoordinated imidazole N atoms and the SCN ^- groups.

Chen Hong-Ji;Yang Guang;Chen Xiao-Ming

Acta Crystallographica Section C Crystal Structure Communications

1999