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The E1/2 potential associated with reduction of the linearly-functionalized 6,6′-biazulenic scaffold is accurately correlated to the combined σp Hammett parameters of the substituents over >600 mV range. X-ray crystallographic analysis of the 2,2′-dichloro-substituted derivative revealed unexpectedly short C–Cl bond distances, along with other metric changes, suggesting a non-trivial cycloheptafulvalene-like structural contribution. [ABSTRACT FROM AUTHOR]

N-benzylcinchonidinium bromide, C26H29N2O+.Br-, with the systematic name (R)-[(2S,4S,5R)-1-benzyl-5-ethenyl-1-azoniabicyclo[2.2.2]octan-2-yl](quinolin-4-yl)methanol bromide, is a quaternary ammonium salt of the cinchona alkaloid cinchonidine. This salt is widely used as a chiral phase-transfer catalyst and chiral resolution agent. Both classical and non-classical hydrogen-bonding interactions, as well as anion effects have been shown to play key mechanistic roles in the catalysis of cinchona alkaloids. In an effort to understand the effects of water on these intermolecular interactions, the structures of anhydrous Nbenzylcinchonidinium bromide, (I), and the sesquihydrate, C26H29N2O+.Br-.-1.5H2O, (II), were determined. [ABSTRACT FROM AUTHOR]

A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two‐electron transformations by one‐electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2 to afford a bimetallic siloxane, featuring two CoII centers, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII/CoII products are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small‐molecule activation that is well‐suited to 3d metals. [ABSTRACT FROM AUTHOR]

A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two‐electron transformations by one‐electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2 to afford a bimetallic siloxane, featuring two CoII centers, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII/CoII products are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small‐molecule activation that is well‐suited to 3d metals. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a series of cyclometallated complexes of Pd(ii) incorporating the mixed donor ligand 1-oxa-4,7-dithiacyclononane ([9]aneS2O) are presented in this study. Complexes of the form [Pd(C^N)([9]aneS2O)](PF6) (C^N = 2-phenylpyridine (ppy) 1b, 4-(2-pyridyl)benzaldehyde (ppyCHO) 2b, 7,8-benzoquinoline (bzq) 3b, 2-benzothienylpyridine (btp) 4b, 2-phenylbenzothiazole (pbt) 5b), were obtained in high-yield from a simple two-step synthetic scheme. All of these complexes were fully characterized by NMR, ESI-MS, IR, combustion analyses, and most (1b, 2b, 4b, 5b) by X-ray crystallography. Solution 1H and 13C NMR studies of [Pd(C^N)([9]aneS2O)](PF6) complexes demonstrate complicated [9]aneS2O behavior at room temperature. Variable temperature NMR reveals dynamic bonding of the [9]aneS2O ligand consistent with the presence of both endodentate and exodentate bonding modes. This is in stark contrast to the related [9]aneS3 (1,4,7-trithiacyclononane) cogeners that demonstrate fluxional endodentate bonding only in solution. X-ray structures reveal only exodenate [9]aneS2O bonding in this series, unlike the related [9]aneS3 complexes that show endodenate bonding with an axial Pd…S interaction. DFT calculations performed on endo and exo [9]aneS2O bonding forms of 4b, as well as a transition state calculation for interconversion, suggest reasonable access to both bonding forms based on the energy barrier. Natural bond order calculations provide further evidence for a weak axial Pd…O interaction in the endo form of 4b. [ABSTRACT FROM AUTHOR]

Direct (hetero)arylation polymerization (DHAP) of a monobrominated benzo[1,2-b:4,5-b′]dithiophene monomer using the Herrmann-Beller catalyst with a tertiary phosphine provided benzodithiophene homopolymers in good yields. Employing both P(o-OMePh)3 and P(o-NMe2Ph)3 as the phosphine ligands gave well-defined polymers—with the later phosphine providing a higher molecular weight polymer. The preparation of a benzodithiophene (BDT) trimer was used to assist in the assignment of the 1H NMR spectra of the synthesized polymers which show largely defect-free couplings. The optical spectra of polymers formed via DHAP and those prepared using traditional Stille couplings are essentially identical, which further confirms the presence of well-defined BDT-BDT couplings along the conjugated polymer chain. These results confirm that carboxylic acid additives are not always necessary to suppress defects in DHAP polymerizations and that DHAP is a viable alternative to traditional Stille coupling for the preparation of benzodithiophene homopolymers. [ABSTRACT FROM AUTHOR]

The title compound, C6H4BrNS, crystallizes in the space group P21/n with one complete molecule in the asymmetric unit. The non-H atoms are nearly planar (r.m.s for non-H atoms = 0.071 Å), with the nitrile group oriented antiperiplanar with respect to the thiophene S atom. Intermolecular Type I centrosymmetric Br. Br halogen interactions are present at a distance of 3.582 (1) Å and with a C--Br. . .Br angle of 140.7 (1)°. Additional weaker C--H. . .N, C--H... S, and S... π interactions are also present. A Hirshfeld analysis indicates Br... πBr interactions comprise only 1.9% of all the interatomic contacts. [ABSTRACT FROM AUTHOR]

The new compound 1-(2-methoxyphenyl)piperazinium chloranilate (MPP.CA) was synthesized and studied by the single crystal X-ray diffraction method. Its structure was confirmed by infrared spectroscopy. The crystal structure consists of ribbons of chloranilate anions and 1-(2-methoxyphenyl)piperazinium cations linked together by NH…O hydrogen bonds. Two protons are transferred from a chloranilic acid molecule to the nitrogen of the piperazine in this structure. Measurements of AC conductivity as a function of frequency at different temperatures indicated the hopping conduction mechanism; in addition, the variation of dielectric constant as a function ofTconfirmed the transition phase indicated by the differential scanning calorimetry (DSC). The physico-chemical properties, UV-Vis, DSC and dielectric properties are described. Hirshfeld surface analyzes all the intermolecular interactions involved within the structure, which are important to stabilize the structure. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of base-stabilized and base-free pincer-type bis(phosphine)/silylene [P2Si]Ru complexes are reported. The base-free complex readily reduces CO2 and CS2via silylene-assisted hydride transfer, affording structurally distinct products with silicon-to-ruthenium formate and dithioformate bridges. [ABSTRACT FROM AUTHOR]

A bis(phosphine)/triflatosilyl pincer-type Rh(i) complex can reversibly store one equivalent of H2 across the Si–Rh bond upon triflate migration from silicon to rhodium. The triflatosilyl complex serves as an effective precatalyst for norbornene hydrogenation, but Si–OTf bond cleavage is not implicated in the major catalytic pathway. The combined findings suggest possible strategies for M/Si cooperation in catalytic processes. [ABSTRACT FROM AUTHOR]

Sandwich coordination complexes, [LnIII(H3L)2]X3∙solvents, of Tb(III), Eu(III), Dy(III), Ho(III) and Er(III) were prepared with two new zwitterionic ester-substituted tripodal amine ligands, tris((2-hydroxy-5-n-butyl benzoate)aminoethyl)-amine (H3L1) and tris((2-hydroxy-5-methyl benzoate)aminoethyl)-amine (H3L2). These ligands were synthesised by condensation of the appropriately substituted salicylaldehyde with tris(2-aminoethyl)amine (tren) followed byin situreduction of the tris-imine to tris-amine. Subsequent 2:1 reaction with lanthanide(III) ions yields [LnIII(H3L)2]X3∙solvents(L = L1,L2; X = Cl−, NO3−;solvents = MeOH or H2O). All complexes were characterised by microanalysis, infrared spectroscopy, high resolution mass spectrometry and solid-state photoluminescence measurements. The crystal structures of [TbIII(H3L1)2]Cl3·6MeOH, [Dy(H3L1)2]Cl3·6MeOH, [EuIII(H3L1)2]Cl3·6MeOH and [TbIII(H3L1)2](NO3)3reveal high-crystallographic −3 symmetry at the O6-coordinated octahedral lanthanide(III) ions and that the tripodal ligands are bound in zwitterionic form: the protons from the phenolic oxygens have migrated to the amino nitrogens. Photoluminescence measurements indicate various degrees of energy transfer of the ligand chromophore to the lanthanide ions, as both ligand and lanthanide emission features are observed. Despite the high-crystallographic symmetry and the likely small transverse magnetic anisotropy of the complexes, no evidence of slow relaxation of the magnetisation, characteristic of a single-molecule magnet, was observed for [TbIII(H3L1)2]Cl3·MeOH·3H2O, [DyIII(H3L1)2]Cl3·6H2O, [HoIII(H3L1)2](NO3)3·2H2O, [ErIII(H3L1)2]·H2O and [TbIII(H3L1)2](NO3)3down to 2.0 K. [ABSTRACT FROM AUTHOR]

A convenient synthetic scheme was developed to access a series of square-planar Pt(ii) complexes of the form (TBA)[Pt(CN)3(CNR)] (TBA = tetra-n-butyl ammonium cation, R = CH3, c-C6H11, p-(C2H5)-C6H4). These heteroleptic complexes were characterized by combustion analyses, single-crystal X-ray structure determinations, HRFAB-MS, 1H NMR, ATR-IR, solution UV-Vis, and solid-state emission spectroscopies. Surprisingly, each of these complexes exhibit low energy room temperature solid-state luminescence in the absence of intermolecular Pt–Pt interactions. Additionally, the polymorphic behavior of (TBA)[Pt(CN)3(CN-c-C6H11)] was elucidated through a combination of single-crystal X-ray structure determinations, X-ray powder diffraction, and mass uptake experiments. Vapoluminescence and polymorphic transformations of (TBA)[Pt(CN)3(CN-c-C6H11)] were concomitant with water vapor absorption. A new double-salt complex [Pt(terpy)Cl] [Pt(CN)3(CNCH3)] (terpy = 2,2′,6′,2′′-terpyridine) was also synthesized and characterized by combustion analysis, ATR-IR, HRFAB-MS, and solid-state UV-Vis and emission spectroscopies. The vapoluminescent properties of this salt in response to water were examined by mass uptake experiments, ATR-IR, and solid-state emission spectroscopy. A principal component analysis (PCA) of the solid-state emission changes induced by water vapor confirmed the presence of an intermediate emissive species. [ABSTRACT FROM AUTHOR]

We report that our previously published molecular square, [{Pt([9]aneS3)(bipy)}4](OTf)8, although quite stable in nitromethane, slowly establishes an equilibrium with another coordination polymer, most likely a triangle, in acetonitrile. Multinuclear measurements on the square precursor complex, [Pt([9]aneS3)Cl2], show acetonitrile coordination upon dechlorination in that solvent, and acetonitrile coordination is additionally confirmed by the solid-state structure of [Pt([9]aneS3)(MeCN)2]2+. We form the complex through the reaction of [Pt([9]aneS3)Cl2] with excess AgPF6 in refluxing MeCN to produce a solid-state solution containing two complex cations with exclusive hexafluorophosphate counterions. Besides [Pt([9]aneS3)(MeCN)2]2+, a second cation is obtained, [Pt([9]aneS3)2]2+, which shows disorder between a double endo and a rare double exo conformation for the two [9]aneS3 ligands. We also report the structures of two Rh(III) thiacrown complexes, cis-[Rh([12]aneS4)Cl2](PF6), which involves cis chloro ligands and an asymmetric binding of the two equatorial sulphur donors, as well as trans-[Rh([16]aneS4)(H2O)(Cl)](OTf)2 with adjacent rather than alternating chair and twist-boat conformations. Lastly, the crystal structure of [{Pd([9]aneS3)(Cl)}2(pyrazine)](OTf)2 displays a pyrazine ligand bridging two [Pd([9]aneS3)Cl]+ moieties with cis stereochemistry of the two chloro ligands. Distortion of the pyrazine ligand is observed, which alleviates strain from bridging the two Pd centres. The extended structure of the complex consists of chains of dimers running parallel to the b-axis of the crystal. [ABSTRACT FROM AUTHOR]

X-ray structural determinations and computational studies were used to investigate halogen interactions in two halogenated oxindoles. Comparative analyses of the interaction energy and the interaction properties were carried out for Br···Br, C-H···Br, C-H···O and N-H···O interactions. Employing Møller–Plesset second-order perturbation theory (MP2) and density functional theory (DFT), the basis set superposition error (BSSE) corrected interaction energy (Eint(BSSE)) was determined using a supramolecular approach. The Eint(BSSE) results were compared with interaction energies obtained by Quantum Theory of Atoms in Molecules (QTAIM)-based methods. Reduced Density Gradient (RDG), QTAIM and Natural bond orbital (NBO) calculations provided insight into possible pathways for the intermolecular interactions examined. Comparative analysis employing the electron density at the bond critical points (BCP) and molecular electrostatic potential (MEP) showed that the interaction energies and the relative orientations of the monomers in the dimers may in part be understood in light of charge redistribution in these two compounds. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C8H18N22+·2I−·CH3CN, the dication lies on a mirror plane containing the mol­ecular dication threefold axis. The structure displays C—H⋯I inter­actions between H atoms of the 1,4-dimethyl-1,4-diazo­nia­bicyclo­[2.2.2]octane dication and the iodide anions. The H⋯I distances are in the range 2.96–3.18 (4) Å. The dications pack forming channels along the b axis, which contain the iodide anions and acetonitrile solvent mol­ecules. [ABSTRACT FROM AUTHOR]

Describes the crystal structure of the organic compound, triethylammonium tetraphenylborate dichloromethane solvate. Distance between ammonium atom H and edge of phenyl ring; Hydrogen bonding; Aromatic rings; Centroids; Intramolecular dihedral angle; Molecular structure.