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The structure of trans-[Pd-(dtco-3-OH)2] (ClO4)2·2DMSO, in which dtco-3-OH is dithiacyclooctan-3-ol and DMSO is dimethyl sulfoxide, was determined by X-ray crystallographic analysis. The crystal data: space group p1, a = 0.7077(2) nm, b = 1.0788(1) nm, c = 1.1111(1) nm, α = 67.710(8)°, β = 73.59(2)°,γ = 85.39(2)°, R1 = 0.0368 and Rw = 0.0998. The palladium (II) is coordinated by four sulfur atoms with a regular square planar configuration. The Pd—S distances are 0.2314(1) and 0.2317(1) nm, respectively. Both dtco-3-OH ligands are in the boat-chair configuration and two hydroxyl groups are on the opposite sites of the PdS4 coordination plane and are towards Pd(II). The Pd—O distance is 0. 285 nm, indicating a weak interaction between them. A typical hydrogen bond between the hydroxyl group of dtco-3-OH ligand and DMSO was observed in the crystal structure. An aqueous solution prepared with the crystals of the complex was used for the investigation of electrospray mass spectrometry (ESMS). Besides trans-[ Pd (dtco-3-OH)2]2+ . 2DMSO observed, in the full scan spectrum of ESMS, all relative species of it, which were probably produced during electrospray ionization process, were also detected. From these experiments, it reveals that ESMS is a powerful tool for studying noncovalent interaction present in solution between inorganic complexes and solvents.

We first make use of aminolysis of calix[4]arene esters to synthesize calix[4]arene amides. When the two ethyl esters of the calix[4]arene esters are aminolysized, the 1, 3-amide derivative is formed selectively. The crystal structures of the calix-[4] arene with two butyl amide (3b) and four butyl amide moieties (4b) were determined. The intermolecular hydrogen bonds make 4b form two-dimensional net work insolid state. The 1H NMR spectra prove mat 3b is of a pinched cone conformation, while 4b and tetraheptylamide-calix[4]arene (6b) take fast interconversion between two C2r isomers in solution and appear an apparent cone conformation at room temperature. As decreasing temperature, the interconversion rate decreases gradually and, finally, the interconversion process is frozen at Tc = −10°C, which makes both conformations of 4b and 6b the pinched cone structures. The hydrogen bond improves the interconversion barrier, and the large different values of the potential barrier between 6b and 4b (or 6b) may be of forming different hydrogen bonds.

The self-assembly and structural characterization of the new ferrocene-containing dicopper(II) double helicate [Cu2L12] (1) and related copper(II) complex [CuL2(CH3CN)][ClO4]2 (2) and silver(I) complexes [AgL2(CH3CN)][BF4] (3) and [AgL2][BF4] (4) have been achieved. These complexes are derived from inexpensive and easy-to-prepare ferrocene-containing bisbidentate Schiff-base ligands H2L1, [(C6H4)(OH)CHNNC(CH3)(C5H4)]2Fe, and L2, [(C5H4N)CHNNC(CH3)(C5H4)]2Fe. The neutral double-helical dicopper(II) complex 1 crystallizes in a polar space group. The two ferrocene-containing ligands strand interwined about each other and around the two tetrahedral copper ions in a double-helical fashion, with the Cu···Cu separation being 9.45 A. The four metal centers are coplanar and form a slightly distorted rhombus with sides of ca. 5.8 A. Reaction of the ligand L2 and copper(II) constructed a mononuclear copper complex, 2. X-ray structural analysis reveals that the copper(II) atom is coordinated in a distorted square pyr...

The conformationally rigid, nickel(II)-based cationic molecular square [Ni(HL)]44+ and copper(II)-based neutral molecular rectangle [Cu2Cl2L]2 were achieved via self-assembly from novel rigid pentadentate N4S ligand bis[phenyl(2-pyridyl)methanone] thiocarbazone (H2L). Crystal structure analyses show that the tetranuclear nickel(II) cation [Ni(HL)]44+ is located at the inversion center with four nickel atoms in the corners of a square with edge length Ni⋯Ni ca. 4.8 A, each metal center being octahedrally coordinated by sulfur atoms, pyridine nitrogen and carbazone nitrogen atoms from two perpendicular HL− ligands. Relative to the square of metal cations the sulfur atoms are midway between the edges of the square, each being connected to two nickel atoms with the angles Ni–S–Ni ca. 163°. The tetranuclear copper(II) complex [Cu2Cl2L]2 is also located in the inversion center with four copper atoms in the corners of a rectangle. Two edges of the rectangle are Cu–S–Cu bridges with edge length Cu⋯Cu of 4.51 A, the other two edges are double Cu–Cl–Cu bridges with Cu⋯Cu distance of 3.41 A. Each metal center is coordinated in a tetragonal-pyramid with the sulfur atom, pyridine nitrogen atom, carbazone nitrogen atom and one chlorine atom comprising the basal plane, whereas the other chlorine atom of the symmetry-related half of the molecule occupies the apical position. The crystal structure of the free ligand is also reported for comparison.

Structures and stabilization due to π–π interactions of N2S2 coordinated nickel(II) complexes NiL2 have been investigated by ESI-MS spectrometry and X-ray diffraction methods. For the systems with HL = 4,5-diazafluoren-9-one thiosemicarbazone (HL1), fluoren-9-one thiosemicarbazone (HL2), fluoren-9-one dithiocarbazone (HL3) and 4,5-diazafluoren-9-one dithiocarbazone (HL4), the Ni(II) atom in each complex is coordinated in a distorted square-planar geometry with two aromatic rings positioned on the same side. This cis configuration is stabilized by π–π stacking interactions between the aromatic rings. Detailed structural analyses reveal that whereas the intermolecular π–π stacking interactions connect NiL12 molecules into a one-dimensional screw chain, the intermolecular π–π stacking interactions and the C–H···π interactions link NiL22 molecules into a dimer. The π–π stacking interactions and the C–H···π interactions among the two phenyl rings and two fluorene rings of NiL32 form a closed hydrophobic brick. In NiL12 one of the two phenyl rings interacts with the two 4,5-diazafluorene rings to give an opened hydrophobic cavity; the edge-to-face interactions about another phenyl ring arrange the molecules into a one-dimensional network.