Density Functional Theory and Low-Temperature Matrix Investigations of CO-Loss Photochemistry from [(C<Subscript>5</Subscript>R<Subscript>5</Subscript>)Ru(CO)<Subscript>2</Subscript>]<Subscript>2</Subscript> (R = H,Me) Complexes

The photochemical CO-loss products of the diruthenium complexes [CpRu(CO) ₂]₂ (5; Cp = ⁵-C₅H₅), [Cp*Ru(CO)₂]₂ (5*; Cp* = ⁵-C₅(CH₃)₅) and CpCp*[Ru(CO)₂]₂ (5) have been studied experimentally in low-temperature (96 K) matrices in 3-methylpentane by using IR spectroscopy. It is proposed that all three complexes undergo single-CO-loss chemistry but that the products have different structures. The single-CO-loss product from 5 is proposed to have one bridging and two terminal carbonyl ligands, whereas 5* and 5 generate triply bridged CO-loss products similar to that observed from [CpFe(CO)₂]₂ and [Cp*Fe(CO)₂]₂. Double-CO-loss from 5* and 5* 9 is also apparently observed. Relativistic DFT calculations have been carried out on various isomers of the starting materials and on potential CO-loss products from 5. The calculations suggest that the triply bridged product Cp₂Ru₂(-CO)₃ (6) might have a singlet ground state in contrast to the corresponding diiron complex Cp₂Fe₂(-CO)₃ (3), which has a triplet ground state.     

Use of poly(sodium oleyl-L-leucylvalinate) surfactant for the separation of chiral compounds in micellar electrokinetic chromatography

A chiral amino acid-based monomeric and polymeric surfactant, sodium oleyl-L-leucylvalinate) (L-SOLV) and poly(sodium oleyl-L-leucylvalinate) (poly-L-SOLV) were synthesized and used for chiral separations in micellar electrokinetic chromatography (MEKC). Poly-L-SOLV was used successfully in the separation of various enantiomers of neutral, acidic, and basic analytes such as 1,1'-bi-2-napthol, 1,1'-binaphthyl-2,2'-diamine, benzoin, hydrobenzoin, benzoin methylether, warfarin, and coumachlor obtaining well-resolved peaks but with only partial separation of temazepam. In addition, the atropisomer 1,1'-binaphthyl-2, 2'-dihydrogen phosphate was chosen to study the applicability of the polymeric surfactant over a wide range of parameters such as concentration, temperature, voltage, and pH. The most striking characteristic of this new surfactant is its high hydrophobicity. It is favorable to interactions with hydrophobic chiral analytes, and thus may provide better chiral recognition for the compounds.     

In‐house and synchrotron X‐ray diffraction studies of 2‐phenyl‐1,10‐phenanthroline,protonated salts,complexes with gold(III) and copper(II), and an orthometallation product with palladium(II)

Different salts of the 2‐phenyl‐1,10‐phenanthrolin‐1‐ium cation, (pnpH)⁺, are obtained by reacting 2‐phenyl‐1,10‐phenanthroline (pnp), C₁₈H₁₂N₂, (I), with a variety of anions, such as hexafluoridophosphate, C₁₈H₁₃N₂⁺·PF₆⁻, (II), trifluoromethanesulfonate, C₁₈H₁₃N₂⁺·CF₃SO₃⁻, (III), tetrachloridoaurate, (C₁₈H₁₃N₂)[AuCl₄], (IV), and bromide (as the dihydrate), C₁₈H₁₃N₂⁺·Br⁻·2H₂O, (V). Compound (I) crystallizes with Z′ = 2, with both independent molecules adopting a coplanar conformation. In (II)–(IV), a hydrogen bond exists between the cation and anion, while one of the lattice water molecules serves as a hydrogen‐bonded bridge between the cation and anion in (V). Reaction of (I) with HAuCl₄ gives the salt complex (IV); however, reaction with KAuCl₄ produces the monodentate complex trichlorido(2‐phenyl‐1,10‐phenanthroline‐κN¹⁰)gold(III), [AuCl₃(C₁₈H₁₂N₂)], (VI). Dichlorido(2‐phenyl‐1,10‐phenanthroline‐κ²N,N′)copper(II), [CuCl₂(C₁₈H₁₂N₂)], (VII), results from the reaction of CuCl₂·2H₂O and (I), in which the Cu^II center adopts a tetrahedrally distorted square‐planar geometry. The pendent phenyl ring twists to a bisecting position relative to the phenanthroline plane. The square‐planar Pd^II complex, bromido[2‐(phenanthrolin‐2‐yl)phenyl‐κ³C¹,N,N′]palladium(II), [PdBr(C₁₈H₁₁N₂)], (VIII), is obtained from the reaction of (I) with [PdCl₂(cycloocta‐1,5‐diene)], followed by addition of bromine. A coplanar geometry for the pendent ring is adopted as a result of the tridentate bonding motif.     

Nanoaggregates of copper porphyrazine in floating layers and Langmuir-Schaefer films

Aggregation behavior of unsubstituted copper porphyrazine (CuPaz) on the water surface was studied by analysis of compression curves, Brewster angle microscopy (BAM), and optical spectroscopy. The structure and stability of the CuPaz aqua aggregates in the floating layers are determined by hydration degree that depends on initial surface concentration and surface pressure. Langmuir-Schaefer (LS) films of CuPaz were prepared by deposition of the variously structured floating layers and studied by X-ray scattering technique and optical spectroscopy. Stable and labile structures were detected and compared with the floating CuPaz aqua aggregates. Conditions of formation of the stable four-stacked nanoaggregates in LS films were determined. A model comprising both nucleation of CuPaz on the water surface and structural transformations in the solid films is proposed.     

X‐ray and synchrotron diffraction studies of 2‐(pyridin‐2‐yl)‐1,10‐phenanthroline in the role of ligand for two copper polymorphs or hydrogen bonded with 2,2,6,6‐tetramethyl‐4‐oxopiperidinium hexafluorophosphate

Different extended packing motifs of dichlorido[2‐(pyridin‐2‐yl)‐1,10‐phenanthroline]copper(II), [CuCl₂(C₁₇H₁₁N₃)], are obtained, depending on the crystallization conditions. A triclinic form, (I), is obtained from dimethylformamide–diethyl ether or methanol, whereas crystallization from dimethylformamide–water yields a monoclinic form, (II). In each case, the Cu^II centre is in a five‐coordinate distorted square‐pyramidal geometry. The extended packing for both forms can be described as a highly offset π‐stacking arrangement, with interlayer distances of 3.674 (3) and 3.679 (3) Å for forms (I) and (II), respectively. The reaction of diprotonated Pt(tmpip₂NCN)Cl [tmpip₂NCN = 2,6‐bis(2,2,6,6‐tetramethylpiperidylmethyl)benzyl] with AgPF₆ under acidic conditions, followed by the addition of 2‐(pyridin‐2‐yl)‐1,10‐phenanthroline, results in a hydrogen‐bonded cocrystal, 2,2,6,6‐tetramethyl‐4‐oxopiperidinium hexafluorophosphate–2‐(pyridin‐2‐yl)‐1,10‐phenanthroline (1/1), C₉H₁₈NO⁺·PF₆⁻·C₁₇H₁₁N₃, (III). The extended packing maximizes π–π interactions in a parallel face‐to‐face arrangement, with an interlayer stacking distance of 3.4960 (14) Å.     

Self‐assembly of a one‐dimensional iron(II) coordination polymer with p‐phenylenebis(picolinaldimine)

catena‐Poly[[[dichloridoiron(II)]‐μ‐N,N′‐bis(2‐pyridylmethylene)benzene‐1,4‐diamine] methanol disolvate], [FeCl₂(C₁₈H₁₄N₄)]·2CH₃OH, forms a one‐dimensional coordination polymer. The polymeric chains run parallel to the c axis. O—H...Cl—Fe and C—H...O hydrogen‐bonding interactions with methanol solvent molecules stabilize the open supramolecular framework. Each Fe^II atom adopts an octahedral geometry coordinated by four N atoms from two N,N′‐bis(2‐pyridylmethylene)benzene‐1,4‐diamine ligands and completed by two cis Cl atoms. The compound has C₂ (and C_i) molecular symmetry, which is coincident with the crystallographic twofold symmetry at (0, y, ). The one‐dimensional structure is propagated via the crystallographic inversion center located at the benzene ring centroid (0, , 0).     

Structural characteristics of different types of nanoparticles synthesised in mesomorphic metal alkanoates

The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC₈) and of the cobalt octanoate (CoC₈). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained.