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A powerful fluorescence technique for imaging individual covalent-bond-forming events in diverse chemical reactions is reported. The generality originates from employing the fluorophore as a spectator rather than a chemical reaction partner. This spectator technique was used to image individual ligand exchange reactions between platinum complexes and sulfur in real time. The chemical reactions were imaged on a key industrial catalyst support, a siloxy-modified surface, providing insight about reactivity distribution on these surfaces. Such reactivity distribution information is not available via traditional solution ensemble techniques, which average the properties of billions of molecules, or via AFM measurements, which provide information about the topology of the surface. Using superlocalization techniques, the positions of individual chemical reactions on the surface were localized below the diffraction limit, with a positional accuracy of up to ±11 nm. [ABSTRACT FROM AUTHOR]

A new class of chiral ferrocenyl diphosphine ligands with an imidazole ring, (Rc,SFc)-ImiFerroPhos, has been prepared from acylferrocenes through a five-step transformation and successfully applied in the Rh-catalyzed asymmetric hydrogenation of various 3-aryl-substituted 2-phosphonomethylpropenoates, in which a series of chiral 3-phosphono-2-arylmethylpropanoic acid derivatives were achieved in ee values of up to 98%. [ABSTRACT FROM AUTHOR]

A new class of unsymmetrical hybrid phosphine-aminophosphine ligands has been prepared from commercially available, inexpensive (S)-1-phenylethylamine through a concise synthetic procedure. These ligands are not very sensitive to air and moisture, and displayed good enantioselectivities in the Rh-catalyzed asymmetric hydrogenation of various dimethyl α-benzoyloxyethenephosphonates bearing β-aryl, β-alkyl, and β-alkoxy substituents and N-benzyloxycarbonyl α-enamido phosphonates, in which up to 97% ee was obtained. A side-by-side comparison study disclosed that these new phosphine-aminophosphine ligands showed better enantioselectivity than BoPhoz ligands. [ABSTRACT FROM AUTHOR]

The photophysical behavior of novel bimetallic Ru(II) and Os(II) complexes having a bridging ligand consisting of two terpyridyl moieties covalently linked in the 4′ position through a distyrylbenzene bridge (tpvpvpt) is reported. The Ru(II) complex has a unique red emission with an excited state lifetime nearly 2000-times longer than the parent complex, [Ru(mpt)2](PF6)2 (mpt = 4′-(methylphenyl)-2,2′,6′,2′′-terpyridine). Combined spectral data suggest the presence of an emissive intra-ligand charge-transfer (ILCT) state lower in energy than the metal-to-ligand charge transfer (MLCT) state. The Os(II) complex exhibits red emission that is similar to that of the parent complex [Os(mpt)2](PF6)2. However, the excited state absorption spectrum reveals a unique transient absorption in the far red that suggests perturbation of the MLCT state by the ILCT state. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C12H8N2)(H2O)4]2(C10H2O8), consists of discrete tetra­aqua­(1,10-phenanthroline)cobalt(II) cations and 1,2,4,5-benzene­tetra­carboxyl­ate anions. The CoII atom is octa­hedrally coordinated by two N atoms of the 1,10-phenanthroline ligand and four O atoms of water mol­ecules. The anion lies on an inversion centre. A two-dimensional hydrogen-bonding network is formed by O atoms of benzene­tetra­carboxyl­ate and the coordinated water mol­ecules. [ABSTRACT FROM AUTHOR]

The article discusses the intermolecular structure of Bis(4-nitrobenzoato)bis(trimethylsilylmethyl)tin(IV). The geometry at the six-coordinate Sn atom is distorted octahedral with an approximately planar equatorial belt made up of the four O atoms of two carboxylate groups and the axial positions occupied by two trimethylsilylmethyl groups. The biological activity of diorganotin compounds depends mainly on the alkyl groups and the ligands The structure of the compound is analogous to that of bis(4 -methoxylbenzo ato)phenyl- (trimethylsilylmethyl)tin(IV). The carboxylate groups act as asymmetric chelating groups.

The novel title ZnII coordination polymer, poly[bis(μ-6-thioxo-1,6-dihydropyridine-3-carboxylato-κ2 S: O)zinc(II)], [Zn(C6H4NO2S)2] n, consists of two crystallographically independent zinc centers and two 6-mercaptonicotinate (Hmna−) ligands. Each ZnII atom is four-coordinated and lies at the center of a distorted tetrahedral ZnS2O2 coordination polyhedron, bridged by four Hmna− ligands to form a two-dimensional (4,4)-network. Each Hmna− ion acts as a bridging bidentate ligand, coordinating to two ZnII atoms through the S atom and a carboxyl O atom. The metal centers reside on twofold rotation axes. The coordination mode of the S atoms and N—H...O hydrogen-bonding interactions between the protonated N atoms and the uncoordinated carboxyl O atoms give the extended structure a wavelike form. [ABSTRACT FROM AUTHOR]

A nickel(II) coordination polymer, catena-poly[[aqua­tri­pyri­dinenickel(II)]-μ-isophthalato], [Ni(C8H4O4)(C5H5N)3(H2O)] n, obtained by reaction of m-bda, pyridine and Ni(NO3)2·6H2O under hydro­thermal conditions, where m-bda is isophthalic acid, was characterized by single-crystal X-ray diffraction. The NiII atom is six-coordinate and lies at the centre of a distorted octa­hedron, coordinated by two carboxylate O atoms from two m-bda ligands, three N atoms from three pyridine mol­ecules and one water mol­ecule. The carboxylate groups of m-bda link the NiII atoms, forming an extended one-dimensional zigzag chain. The chains are then knitted together, forming a two-dimensional supramolecular arrangement, via C—H⋯O hydrogen bonds between the H atoms of pyridine rings and the coordinated carboxylate O atoms of m-bda. [ABSTRACT FROM AUTHOR]

A series of new tetrathiafulvalene-substituted 3,5-dimethylpyrazole ligands, 4-[{2,6,7-tris(methylthio)-TTF-3-yl}thio]-3,5-dimethylpyrazole (MTSPz*, Pz* = 3,5-dimethylpyrazole, 4a), 4-[{6,7-benzo-2-(methylthio)-TTF-3-yl}thio]-3,5-dimethylpyrazole (BTSPz*, 4b), 4-[{6,7-(ethylenedithio)-2-(methylthio)-TTF-3-yl}thio]-3,5-dimethylpyrazole (ETSPz*, 4c) and 4-[{6,7-(propylenedithio)-2-(methylthio)-TTF-3-yl}thio]-3,5-dimethylpyrazole (PTSPz*, 4d), have been prepared by an efficient synthetic route. Further coordination reactions of the respective ligands with Re(CO)5Cl afford new rhenium(I) tricarbonyl chloro complexes, ClRe(CO)3(MTSPz*)2(5a), ClRe(CO)3(BTSPz*)2(5b), ClRe(CO)3(ETSPz*)2(5c) and ClRe(CO)3(PTSPz*)2(5d). The crystal structures of the ligand 4dand complexes 5b−dhave been determined by X-ray crystallography, showing nearly planar TTF units in these compounds, and the distorted octahedral geometry in all complexes. The absorption spectra and multiredox behaviors of these new compounds (4a−d, 5a−d) have been studied, and are rationalized based on density functional theory. The results suggest that the novel redox-active tetrathiafulvalene-pyrazole ligands are useful for the syntheses of new metal complexes. [ABSTRACT FROM AUTHOR]

In the title compound, [Zn(C13H9N2O)2]·2C3H7NO, the ZnII ion is located on a twofold axis and chelated by two 2-(2- hydroxyphenyl)benzimidazole ligands with a distorted tetrahedral geometry. [ABSTRACT FROM AUTHOR]

Dynamic materials have been widely studied for regulation of cell adhesion that is important to a variety of biological and biomedical applications. These materials can undergo changes mainly through one of the two mechanisms: ligand release in response to chemical, physical, or biological stimuli, and ligand burial in response to mechanical stretching or the change of electrical potential. This study demonstrates an encrypted ligand and a new hydrogel that are capable of inducing and inhibiting cell adhesion, which is controlled by molecular reconfiguration. The ligand initially exhibits an inert state; it can be reconfigured into active and inert states by using unblocking and recovering molecules in physiological conditions. Since molecular reconfiguration does not require the release of the ligand from the hydrogels, inhibiting and inducing cell adhesion on the hydrogels can be repeated for multiple cycles. [ABSTRACT FROM AUTHOR]

Utilizing the mixed-ligand strategy, a novel fourfold-interpenetrated 3D homochiral metal-organic framework (1) with rare pair quadruple-stranded helices was assembled from bpee (1,2-bis(4-pyridyl)ethylene) and NCG (N-carbamyl-l-glutamate). Changing the carbamyl substituent of NCG with benzoyl group (NBzG: N-benzoyl-l-glutamate), a non-interpenetrated 3D homochiral coordination polymer (2) composed of alternate right-handed and left-handed single helix was obtained. When p-tolylsulfonyl substituent was used instead, an interesting homochiral linear structure (3) was formed from mixed-ligand bpee and NTsG (N-p-tolylsulfonyl-l-glutamate), with all individual NTsG being lined up orderly. The steric hindrance of N-substituent of l-glu has a tremendous impact on the construction of these diverse frameworks. Complexes 1-3 display second harmonic generation (SHG) efficiencies, which are approximately 0.32, 0.45, and 0.55 times as much as that of KDP powder. [ABSTRACT FROM AUTHOR]

The article discusses the intermolecular structure of (Bis[μ-bis(diphenylphosphino)methane-κ2P:P']-bis[(1,10-phenanthroline-κ2 N,N')copper(I)] bis(tetrafluoroborate) dichloromethane disolvate. In the structure, the two Copper centres are bridged by two bis(diphenylphosphino)methane (dppm) ligands to form a centrosymmetric eight-membered Cu2P4C2 ring. The coordination of polyhedron of each Cu atom is distorted tetrahedral. The four-electron-donor diphosphine ligand, bis(diphenyl- phosphino)methane (dppm), is a very efficient bridging bidentate ligand and can form polynuclear complexes with most metal ions.

By employing a rigid tripodal ligand 1,3,5-tris(1-imidazolyl)benzene (tib) to assemble with two different Cd(II) salts, we have obtained two distinct cationic metal-organic frameworks, [Cd(tib)2·2NO3·4DMF]n (1) and [Cd(tib)2·2ClO4·4DMF]n (2) (DMF = N,N-dimethylformamide). The compounds were structurally characterized by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Both compounds 1 and 2 are constructed based on 2D square lattice (sql) nets, through ligand-to-axial (L-A), pillared by triangular tib ligands, resulting in two diverse 3D pillar-layered architectures. Compound 1 features a cationic framework with a (3,6)-connected rtl topology and has rhomboid channels; while for 2, the 2D layers repeat in an ···ABAB··· staggered stacking mode pillared by tib ligands, resulting in a different cationic framework from 1 with a pyr net. The results demonstrate that counterions NO3- and ClO4- play an important role in the fabrication of structures of 1 and 2. Furthermore, the photoluminescence of compounds 1 and 2 have been investigated in the solid state at ambient temperature. [ABSTRACT FROM AUTHOR]

A new family of chiral ferrocenyl P,S-ligands has been developed and successfully applied in a highly endo-selective catalytic asymmetric cycloaddition of azomethine ylides with various enones, including cyclic and acyclic α-enones. For cyclic α-enones, a [Cu(CH3CN)4]ClO4/(Rc,SFc)-2fcomplex catalyzed the cycloaddition to give the sole endo-cycloadducts in perfect enantioselectivities (normally 99% ee), while an AgOAc/(Rc,SFc)-2fcatalytic system exhibited good endo/exoselectivities (endo/exo= 91/9 to 96/4) and high enantiocontrol (up to 98% ee) for acyclic α-enones. [ABSTRACT FROM AUTHOR]

An enantioselective synthesis of chiral alkylphosphonates bearing a β-stereogenic center, based on the Rh-catalyzed asymmetric hydrogenation of corresponding β-substituted β,γ-unsaturated phosphonates with a ferrocenebased monophosphoramidite ligand under the mild hydrogenation conditions, was developed, in which an ee value of up to 98% was obtained. [ABSTRACT FROM AUTHOR]

The coordination environment of copper(II) in the title compound, [Cu(C6H4NO3)(NO3)(C12H8N2)], is square pyramidal; the basal plane comprises the two N atoms of 1,10-phenanthroline and the two O atoms of picolinate N-oxide, with the apical position occupied by a nitrate O atom. [ABSTRACT FROM AUTHOR]

The centrosymmetric mol­ecule of the title CdII complex, [Cd3(C10H7N6O)6], is located on a threefold axis. The pyridopyrimidine ligands bridge neighbouring Cd atoms, forming a trinuclear complex. π–π Stacking is observed between neighbouring complex mol­ecules. [ABSTRACT FROM AUTHOR]

The title cobalt(II) coordination polymer, [Co(C16H8O8)(C10H8N2)2] n, was obtained by the reaction of Co(OAc)2·4H2O (OAc is acetate), 4,4′-bipyridine (4,4′-bpy) and biphenyl-3,4,3′,4′-tetra­carboxylic acid (H4 L) under hydro­thermal conditions. Each CoII atom lies at the centre of a distorted octa­hedron, coordinated by four O atoms from three H2 L2− and two N atoms from two monodentate 4,4′-bpy ligands. Each H2 L2− ligand coordinates to three CoII centres through two carboxyl­ate groups, one acting as a bridging bidentate group and the other in a chelating bidentate fashion. Two Co atoms, two H2 L2− and four 4,4′-bpy ligands form a ring dimer node, and these nodes link into an extended broad chain along the c axis. [ABSTRACT FROM AUTHOR]