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Whilst inert to electrochemical stimulus, acid-induced ring-opening of an ethynyl spiropyran ligand in Ru complexes proceeds to form the protonated merocyanine, that can be switched from the Z- to E-form by UV light.

We report an improved method for the controlled solvent-phase decomposition of ferrocene into highly crystalline monodisperse iron oxide nanoparticles at relatively low temperatures. Solution-phase decomposition of ferrocene into nanoparticles has received little attention in the literature, due to the percieved stability of ferrocene. However, we synthesised wüstite FeO-iron oxide core-shell nanoparticles by thermally decomposing ferrocene in 1-octadecene solvent and in the presence of oleic acid and oleylamine, as surfactants. We report procedures that provide cubic and spherical core-shell iron oxide nanoparticles whose size (29.3 ± 2.3 nm for spheres, 38.6 ± 6.9 nm for distorted cubes and 23.5 ± 2.4 nm for distorted cubes with concave faces) and shape can be controlled through simple adjustments to reaction parameters. Transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy-loss spectroscopy and powder X-ray diffraction analysis methods were used to characterise the nanoparticles.

The novel 2,7-bis((TIPS)ethynyl)-10b,10c-diethyldihydropyrene photochrome (TIPS = triisopropylsilyl) was observed to undergo thermal rearrangement to 2,7-bis(TIPS-ethynyl)-pyrene in the solid state...

High-resolution 100 K X-ray and neutron single-crystal diffraction data of the non-stoichiometric hydroquinone-CO2 (HQ-CO2) clathrate are combined, with the aim of providing further insight into host-guest binding in hydroquinone clathrates, measuring the electrostatic nature of the cavity formed by the HQ host and, for the first time, estimating the quadrupole moment of the CO2 guest molecule via diffraction techniques. The experimental electron density reveals the cavity in the β-HQ structure to be moderately electronegative and largely featureless, but this does not mean that guest molecules are merely trapped. Calculated binding energies for a series of HQ clathrates reveal strong interactions with the host system and, in the case of CO2, a thermodynamic stability comparable to, or exceeding, that of many molecular cocrystals. The remarkable flexibility of the β-HQ host structure is explored through an analysis of its available clathrate structures at 100 K as well as calculated elastic tensors for crystals of β-HQ and the HQ-CO2 clathrate. Establishing the CO2 quadrupole moment from this analysis of the experimental diffraction data proves challenging, but the sign and estimated range of its magnitude are in agreement with spectroscopic measurements in the gas phase.

This paper describes the syntheses of several functionalized dihydropyrene (DHP) molecular switches with different substitution patterns. Regioselective nucleophilic alkylation of a 5-substituted dimethyl isophthalate allowed the development of a workable synthetic protocol for the preparation of 2,7-alkyne-functionalized DHPs. Synthesis of DHPs with surface-anchoring groups in the 2,7- and 4,9-positions is described. The molecular structures of several intermediates and DHPs were elucidated by X-ray single-crystal diffraction. Molecular properties and switching capabilities of both types of DHPs were assessed by light irradiation experiments, spectroelectrochemistry, and cyclic voltammetry. Spectroelectrochemistry, in combination with density functional theory (DFT) calculations, shows reversible electrochemical switching from the DHP forms to the cyclophanediene (CPD) forms. Charge-transport behavior was assessed in single-molecule scanning tunneling microscope (STM) break junctions, combined with density functional theory-based quantum transport calculations. All DHPs with surface-contacting groups form stable molecular junctions. Experiments show that the molecular conductance depends on the substitution pattern of the DHP motif. The conductance was found to decrease with increasing applied bias.

Developing molecular circuits that can function as the active components in electrical devices is an ongoing challenge in molecular electronics. It demands mechanical stability of the single-molecule circuit while simultaneously being responsive to external stimuli mimicking the operation of conventional electronic components. Here, we report single-molecule circuits based on spiropyran derivatives that respond electrically to chemical and mechanical stimuli. The merocyanine that results from the protonation/ring-opening of the spiropyran form showed single-molecule diode characteristics, with an average current rectification ratio of 5 at ±1 V, favoring the orientation where the positively charged end of the molecule is attached to the negative terminal of the circuit. Mechanical pulling of a single spiropyran molecule drives a switch to a more conducting merocyanine state. The mechanical switching is enabled by the strong Au-C covalent bonding between the molecule and the electrodes, which allows the tensile force delivered by the STM piezo to break the molecule at its spiropyran C-O bond.

The observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro-XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit-cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit.

Several trinuclear ferrocenes are obtained by Friedel-Crafts reaction of octamethylferrocene with ferrocenoyl chloride and subsequent modifications. 1,1'-Diferrocenoyloctamethylferrocene (3) is transformed to the divinyl derivative (4a) by reaction with MeLi and AlCl

We investigate how a number of physical parameters control the rate and pattern of nanoparticle assemblage onto a commercially available alumina surface. 8 nm e-Co nanoparticles supported on polycrystalline alumina are found to have areas of both good dispersion and areas of aggregation. A similar pattern of dispersion was also observed for larger (∼30 nm) polycrystalline ferromagnetic e-Co nanoparticles. Acid and base treatment of the amphoteric support material prior to the assemblage process is found to have little impact on dispersion of the particles. Using a nonpolar solvent for the assemblage process eliminates the effect of zeta potential and allows for rapid attachment of particles to the support. Performing the assemblage in a polar solvent is found to significantly decrease the rate of the particle attachment to the support. Despite the slower attachment of particles, there is no impact on the nanoparticle distribution pattern. In contrast to the mixed dispersion observed when assembling nanoparticles on an alumina support, e-Co nanoparticles are found to disperse uniformly across an ordered mesoporous MCM-41 silica support. It seems likely that a specific chemical interaction between the support surface and nanoparticle are dictating the assemblage process.

The Ley–Griffith reaction is utilized extensively in the selective oxidation of alcohols to aldehydes or ketones. The central catalyst is commercially available tetra-n-propylammonium perruthenate (TPAP, n-Pr4N[RuO4]) which is used in combination with the co-oxidant N-methylmorpholine N-oxide (NMO). Although this reaction has been employed for more than 30 years, the mechanism remains unknown. Herein we report a comprehensive study of the oxidation of diphenylmethanol using the Ley–Griffith reagents to show that the rate determining step involves a single alcohol molecule, which is oxidised by a single perruthenate anion; NMO does not appear in rate law. A key finding of this study is that when pure n-Pr4N[RuO4] is employed in anhydrous solvent, alcohol oxidation initially proceeds very slowly. After this induction period, water produced by alcohol oxidation leads to partial formation of insoluble RuO2, which dramatically accelerates catalysis via a heterogeneous process. This is particularly relevant in a synthetic context where catalyst degradation is usually problematic. In this case a small amount of n-Pr4N[RuO4] must decompose to RuO2 to facilitate catalysis.

The reaction of [Ru3(CO)10(μ-dppm)] (1) with 4-ethynyl-2,2′-bipyridine (2) or 5-ethynyl-2,2′-bipyridine (3) affords the Ru3C2 clusters [Ru3(μ-H)(μ3-C2bpy)(CO)7(dppm)] (bpy = 4-bpy, 4 (22%); bpy = 5-bpy, 5 (55%)). Complexes 4 and 5 have been fully characterised by NMR spectroscopy, with 2D-COSY methods being used to aid 1H NMR assignments, and single crystal X-ray diffraction. The pendant bipyridyl moiety presents as a site for further reaction using the ‘Tinkertoy’ approach, and subsequent reactions of 4 and 5 with PdCl2(NCPh)2 affords the bimetallic complexes [Ru3(μ-H){μ3-C2bpy(κ2-N′,N–PdCl2)}(CO)7(dppm)] bpy = 4-bpy, 6 (55%); bpy = 5-bpy, 7 (35%)).

This paper describes the facile preparation of 1,1′-diacetyloctamethylferrocene (2) by acylation of octamethylferrocene (1) with acetyl chloride. Chloroformylation with POCl3/DMF of 2 affords a variety of products, including 1,1′-bis-(1-chlorovinyl)octamethylferrocene (3b) in high yield. Compound 3b cyclises in aqueous sodium hydroxide/DMF to an octamethyl[1,4]-ferrocenophane bearing a 1-dimethylaminobuta-1,3-diene-handle (4).

Epsilon cobalt (ε-Co) nanoparticles in a number of octahedral morphologies have been synthesised. The particles are polycrystalline, with sizes in the order of 30 nm. Magnetic studies reveal the particles are ferromagnetic, with a room temperature saturation magnetisation of 131 emu g(-1). Unlike other large cubic ε-Co syntheses, we have not added an additional co-surfactant. Instead, we have modified the heating regime and reaction agitation. This alternative method highlights the complex chemistry associated with the formation of cobalt nanoparticles by thermal decomposition.

Multinuclear metal complexes have shown a unique capacity to provide interesting magnetic, chemical and electronic properties by virtue of the remarkably diverse range of structural types that they exhibit. Calix[n]arenes are now a mature synthetic platfom that provide for a diverse spatial arrangement of binding groups, making them highly suitable to use for the formation of multinuclear metal ion complexes. Increasing interest has been shown in the development and properties of magnetic materials based on calixarene macrocycles. Here, we review the magnetic properties of calixarene-supported metal clusters with emphasis on those examples exhibiting slow magnetic relaxation.

Crystalline molecular complexes of 18-crown-6 with three sulfonamide analogues (methane, benzene, and toluene sulfonamides) have been synthesized and characterized. Among these, the 18-crown-6:benzenesulfonamide complex exhibits three crystal forms, including a polymorphic pair. Interaction energy calculations show that the host–guest binding energies in these complexes are very high (∼92–104 kJ·mol–1). Energy framework analysis identifies the hierarchy of intermolecular interactions and their topology; a trimeric motif formed by two guest molecules and a crown host is found to be a salient structural feature in these complexes. This study establishes the “sulfonamide-crown motif” as a very robust and predictable supramolecular recognition unit.

We describe how the 4,5-diazafluoren-9-yl moiety has been utilized in the construction of multinuclear complexes incorporating a ruthenium(II) allenylidene functionality. The coordination chemistry of diazafluorenyl-terminated allenylidene complexes is limited by the sensitivity (instability) of the allenylidene moiety under a variety of synthetic conditions. In contrast the κ2-N,N′-coordination of the diazafluorenyl propargylic alcohol (alkynol) to a metal center prior to allenylidene formation provides a facile route toward the synthesis of multinuclear allenylidene coordination complexes. Our synthetic attempts and successes are discussed in combination with spectroscopic and electronic characterization of the latter cases.

In this report we describe the design and preparation of a new air-stable nickel phosphite based catalyst for unique C–N bond forming processes. Specifically, (BINAP)Ni[P(OPh)3]2, is presented as an effective catalyst for a range of amination reactions between aryl halides and primary alkylamines. The results are supported by relevant kinetic studies, DFT calculations and a catalytic cycle indicating possible reaction intermediates.

A number of group 11 salts, [MX] (M = Ag, X– = –O3SCF3, –O2CCF3, BF4–; M = Cu; X = Cl, Br) and [Cu(MeCN)4][PF6], were found to react in varying stoichiometries with ethyne-1,2-diyl compounds, [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] (R = H, Me), to give a number of complex cations. The trication salts [Ag3({Ru(CO)2(η-C5H4Me)}2(μ2-η1:η1-C≡C))3](O3SCF3)3, [Ag3({Ru(CO)2(η-C5H4R)}2(μ2-η1:η1-C≡C))({Ru(CO)2(η-C5H4R)}2(μ2-η1:η2-C≡C))2](BF4)3, and [Cu3({Ru(CO)2(η-C5H4R)}2(μ2-η1:η2-C≡C))({Ru(CO)2(η-C5H4R)}2(μ2-η2-C≡C))](PF6)3 result from the use of the respective anion salts in their syntheses. Coordination of Ag+ by the ethyne-1,2-diyl complexes in the presence of F3CCO2– yields the tetranuclear complexes [Ag4({Ru(CO)2(η-C5H4R)}2(μ2-η2-C≡C))2](μ2-O2CCF3)4 (R = H, Me). The reaction of CuCl does not afford the discrete dimeric complexes normally observed for internal alkynes and metal alkynyl complexes but, rather, the 1-D polymer [Cu2(μ-Cl)2({Ru(CO)2(η-C5H4R)}2(η2-C≡C))](∞|∞), while CuBr gives the discrete dimer motif known in the literature. The solution structures at 1/2, 1/1, and 2/1 stoichiometries of Ag+/[{Ru(CO)2(η-C5H5)}2(μ2-C≡C)] have been probed spectroscopically, and the {Ru(CO)2(η-C5H4R)} environments appear to be equivalent and, likewise, the resonances attributable to their C≡C units. In a subsequent reaction of [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] and AgBF4 use of a strict Ag+/ethyne-1,2-diyl ratio gave [Ag({Ru(CO)2(η-C5H5)}2(η2-C≡C))2](BF4). The analogous Cu+ adduct [Cu({Ru(CO)2(η-C5H5)}2(η2-C≡C))2](PF6) is observed, along with the tricopper(I) adduct from the reaction of [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] and [Cu(NCMe)4](PF6). A combination of factors appears to control the solid-state structures of these coinage metal adducts, with the anion found to be that which influences the packing to the greatest extent.

This paper describes the facile synthesis of a number of electron rich octamethyl[1.4]ferrocenophanes with unsaturated handles from 1,1'-bis(1-chlorovinyl)octamethylferrocene. Treatment of this reactive compound with sodium hydroxide in DMF initiates a series of reactions resulting in the formation of four different ferrocenophanes. The most complex of these products arises from a cascade of cyclisations giving an unusual, unsymmetrical bis-ferrocenophane with a central fused cyclobutene. Control over the reaction outcome is achieved by manipulating the concentration of NaOH. Mechanisms are proposed, and supported by DFT calculations.

Bending in molecular crystals is typically associated with the anisotropy of intermolecular interactions. The intriguing observation is reported of plastic bending in dimethyl sulfone, which exhibits nearly isotropic crystal packing and interaction topology, defying the known structural models of bending crystals. The origin of the bending phenomenon has been explored in terms of intermolecular interaction energies, experimental X-ray charge density analysis, and variable temperature neutron diffraction studies. H⋅⋅⋅H dihydrogen interactions and differences in electrostatic complementarity between molecular layers are found to facilitate the bending behavior.

4-Ethynyl-2,2′-bipyridyl-substituted ruthenium alkynyl complexes have been prepared and used to access a range of binuclear homometallic ruthenium and heterometallic ruthenium–rhenium complexes. These have been characterized by a variety of spectroscopic and single-crystal X-ray diffraction experiments. The IR spectra of a number of these ruthenium alkynyls display multiple ν(C≡C) bands in the IR spectra, which are rationalized in terms of putative conformational isomers, whose calculated infrared stretching frequencies are comparable to those obtained experimentally. The mononuclear alkynyl ruthenium complexes undergo reversible one-electron oxidations centered largely on the alkynyl ligands, as inferred from the significant shift in ν(C≡C) frequency on oxidation, while the binuclear complex [Ru{C≡C-4-bpy-κ2-N,N′-RuClCp}(dppe)Cp*]+ undergoes initial oxidation at the very electron rich {RuCl(bpy)Cp} fragment, causing only a small change in ν(C≡C). A combination of IR and UV–vis spectroelectrochemical expe...

Bipyridyl appended ruthenium alkynyl complexes have been used to prepare a range of binuclear homometallic ruthenium and heterometallic ruthenium–rhenium complexes. The two metal centers are only weakly coupled, as evinced by IR and UV–vis–near NIR spectroelectrochemical experiments and supported by quantum chemical calculations. The alkynyl complexes of the type [Ru(C≡Cbpy){Ln}] ({Ln} = {(PPh3)2Cp}, {(dppe)Cp*}, {Cl(dppm)2}) undergo reversible one-electron oxidations centered largely on the alkynyl ligands, as has been observed previously for closely related complexes. The homometallic binuclear complexes, exemplified by [Ru(C2bpy-κ2-N′N-RuClCp)(PPh3)2Cp] undergo two essentially reversible oxidations, the first centered on the (C2bpy-κ2-N′N-RuClCp) moiety and the second on the Ru(C≡Cbpy)(PPh3)2Cp fragment, leading to radical cations that can be described as Class II mixed-valence complexes. The heterometallic binuclear complexes [Ru(C2bpy-κ2-N′N-ReCl(CO)3){Ln}] display similar behavior, with initial oxid...

The new Ni-catalyst is extremely effective in the amination reaction of various amines with arylchlorides and bromides.

X-ray/neutron (X/N) diffraction data measured at very low temperature (15 K) in conjunction with ab initio theoretical calculations were used to model the crystal charge density (CD) of the host-guest complex of hydroquinone (HQ) and acetonitrile. Due to pseudosymmetry, information about the ordering of the acetonitrile molecules within the HQ cavities is present only in almost extinct, very weak diffraction data, which cannot be measured with sufficient accuracy even by using the brightest X-ray and neutron sources available, and the CD model of the guest molecule was ultimately based on theoretical calculations. On the other hand, the CD of the HQ host structure is well determined by the experimental data. The neutron diffraction data provide hydrogen anisotropic thermal parameters and positions, which are important to obtain a reliable CD for this light-atom-only crystal. Atomic displacement parameters obtained independently from the X-ray and neutron diffraction data show excellent agreement with a |ΔU| value of 0.00058 Å(2) indicating outstanding data quality. The CD and especially the derived electrostatic properties clearly reveal increased polarization of the HQ molecules in the host-guest complex compared with the HQ molecules in the empty HQ apohost crystal structure. It was found that the origin of the increased polarization is inclusion of the acetonitrile molecule, whereas the change in geometry of the HQ host structure following inclusion of the guest has very little effect on the electrostatic potential. The fact that guest inclusion has a profound effect on the electrostatic potential suggests that nonpolarizable force fields may be unsuitable for molecular dynamics simulations of host-guest interaction (e.g., in protein-drug complexes), at least for polar molecules.

Amphiphiles incorporating a complexed metal ion centre, viz . macrobicyclic hexamine ligands termed ‘sarcophagines’, have been investigated as templating agents in the synthesis of mesoporous silicas. Materials were prepared using copper and cobalt containing metallosurfactants in two different synthetic procedures that produced several materials that appeared to incorporate the metals into the porous silica structures. The copper containing materials displayed aggregation of the metal at the high temperatures employed during calcination, whilst the cobalt materials did not appear to aggregate under the same conditions. The materials were all characterised by powder X-ray diffraction, transmission electron microscopy and BET surface area measurements, which showed that the products were well ordered, hexagonally arranged metal incorporated materials with high surface areas.

The interaction between hexabromoethane and [CpRu(CO)2Br] (Cp = (η-C5H5), results in the deposition of two different isostoichiometric co-crystals, 2[CpRu(CO)2Br]·C2Br6, one crystallising in space group P (Z = 1) and the other in P21/n (Z = 4). These were produced in the reaction of HCBr3 and [(CpRu(CO)2)2] under indoor illumination, following a slight modification of the literature procedure. The origin of the hexabromoethane is as yet unknown but it appears to have been formed in the reaction rather than being an impurity in the bromoform. We have analysed the structures using the Hirshfeld surface approach and electrostatic potentials, supported by DFT theoretical calculations to better define the nature of intermolecular interactions in the solid state. The results indicate that the most significant interactions within both crystal forms arise not from the closest van der Waals contacts but, rather, from more distant interactions between the unsymmetrical electron distributions about the bromine atoms in the solvate and substrate molecules.

Single crystal X-ray studies are presented for the ‘piano-stool’ structures [CpRu,Os(CO)2Cl], [Cp′Ru(CO)2X] (X = Cl, Br, I (redetermination)), [Cp*Ru(CO)2Cl] (two phases), enabling the assembly of comparative geometric data for the [CpM(CO)2Cl] (M = Fe, Ru, Os), [Cp,Cp′Ru(CO)2X] (X = Cl, Br, I) and [CpxRu(CO)2Cl] (Cpx = Cp (η–C5H5), Cp′ (η–C5H4CH3), Cp* (η–C5CH3)5,CpPh (η–C5(C6H5)5)). In the [Cp′Ru(CO)2X] arrays, the methyl groups are found to consistently lie ‘eclipsed’ vis-a-vis the halogen substituents, with a concomitant tilt of the Cp ring; the reasons for this are explored theoretically.

The crystal structure of the β-polymorph of hydroquinone (β-HQ), the apohost of a large family of clathrates, is reported with a specific focus on intermolecular interactions and the electrostatic nature of its cavity. Hirshfeld surface analysis reveals subtle close contacts between two interconnecting HQ networks, and the local packing and related close contacts were examined by breakdown of the fingerprint plot. An experimental multipole model containing anisotropic thermal parameters for hydrogen atoms has been successfully refined against 15(2) K single microcrystal synchrotron X-ray diffraction data. The experimental electron density model has been compared with a theoretical electron density calculated with the molecule embedded in its own crystal field. Hirshfeld charges, interaction energies and the electrostatic potential calculated for both models are qualitatively in good agreement, but small differences in the electrostatic potential persist due to charge transfer from all hydrogen atoms to the oxygen atoms in the theoretical model. The electrostatic potential in the center of the cavity is positive, very shallow and highly symmetric, suggesting that the inclusion of polar molecules in the void will involve a balance between opposing effects. The electric field is by symmetry zero in the center of the cavity, increasing to a value of 0.0185 e/Å(2) (0.27 V/Å) 1 Å along the 3-fold axis and 0.0105 e/Å(2) (0.15 V/Å) 1 Å along the perpendicular direction. While these values are substantial in a macroscopic context, they are quite small for a molecular cavity and are not expected to strongly polarize a guest molecule.

Two propargylic alcohols incorporating a thienyl moiety were synthesized, and their subsequent reaction to form allenylideneruthenium(II) complexes is reported. The alkynol 4-hydroxy-4-ethynylcyclopenta[2,1-b:3,4-b′]dithiophene (4) reacts with cis-[RuCl2(P∩P)2] (P∩P = dppm, dppe) to afford the allenylidene complexes trans-[RuCl(P∩P)2{═C═C═C(4-cyclopentadithiophene)}]PF6 (P∩P = dppm, 5a; dppe, 5b). Similar reactions of cis-[RuCl2(P∩P)2] with 1,1-di(2′-thienyl)prop-2-yn-1-ol (2) yield products consistent with formulation as an allenylideneruthenium(II) complex, although with no identifiable counteranion. In contrast the reaction of 2 with [RuClCp(dppe)] readily affords the deep purple complex [RuCp(dppe){═C═C═C(2-thienyl)2}]PF6. The complexes have been characterized by spectroscopy and mass spectrometry, and a single-crystal X-ray structural determination of complex 5a was undertaken. The allenylidene complexes obtained in a pure state have also been investigated through cyclic voltammetry, and preliminary ...

[Extract] This special issue on Coordination Chemistry in Australia comes 20 years after its predecessor and combines current activities in Australia with submissions from participants at the 6th Asian Coordination Chemistry Conference (ACCC6) that was held as part of the RACI Centenary Congress in July 2017.

In extension of previous work involving structural characterisation of complex salts formed between main group 1 metal ions and p-tert-butyltetrathiacalixarene, LH4, the present study encompasses complexes with a wider array of main group 2, 13, 14 metal ions. For group 2, single-crystal X-ray structural characterisation of Ca(LH3)2·3dmf (1a), {Ca(LH2)·3dmf}2 (1b), Ba(LH3)2·6dmf (2a) and BaCO3·3Ba(LH3)2·3H2O·3CH3CN·12.25CH2Cl2 (2b) provides models for various coordination units. For group 13, this applies to {Ga(OH)(LH2)·3.5dmf}2 (3), {In(LH)·4EtOH·2CH2Cl2}2 (4a) and {In(OH)(LH2)·3CH2Cl2}4 (4b), and for group 14, to OPb4(LH)2·6dmf·dmso·2H2O (5). Overall, these define mononuclear (1a, 2a), binuclear (1b, 3, 4b) and tetranuclear (2b, 4b, 5) species. The calixarene cavities frequently include solvent molecules, though this capacity is clearly influenced by the nature of the bound metal ion(s) and their binding, as well as the associated impact on the conformation of the calixarene ligand(s).

Extension of previous work on the lanthanide(III) ion complexes of p-tert-butyltetrathiacalix[4]arene has led to a variety of structurally characterised species containing oxo-, hydroxo- and aqua-ligands presumably derived from water present in the preparative medium, along with the thiacalixarene in various stages of deprotonation. The overall stoichiometry of some species is remarkably complicated due to the presence of simple anions and multiple solvents. Simplest is the binuclear complex [(μ-H2O){Ln(O-dmf)2}2(HL·dmf)2]·nS (dmf = dimethylformamide) [1Ln, Ln = Sm (nS = 2dmf), Eu (nS = 1.5dmf·2MeCN)], also the best-defined of all the arrays studied. The heaviest lanthanides give trinuclear Ln(OH)3·2Ln(LH)·xdmf·yH2O (2Ln, Ln = Yb, Lu), while both oxo and hydroxo species are isolable with Eu: trinuclear Eu3O(L)(LH)(LH4)·13dmf (3) and tetranuclear Eu4O(OH)2(L)(LH2)2(LH4)·12dmf (9), both somewhat atypical species containing uncoordinated thiacalixarene molecules within the lattice. Anion (NO3, ClO4) coordination, as in the tri- and tetranuclear species, 4–6Ln, 9, 10Ln, 11Ln, 12, seems especially favoured for the lighter lanthanides. In these arrays, the Ln3 and Ln4 aggregates are triangular or (quasi-)square-planar, except for Gd4O2(LH2)4·2H2O·2MeOH·2dmf·3.375CH2Cl2 (12), where there is a Z-disposition. Most common is an Ln3O core, which spans the gamut of Ln in three sets of crystal forms with cells of similar dimensions: for Ln = La...Nd, Ln3(OH)(NO3)4(LH2)2·4.5dmf (5Ln) (space group C2/m), and Sm...Lu, Ln3O(NO3)(LH)2·4H2O·2dmso·2MeCN·3py (6Ln) (space group P21/n), conformity with crystallographic symmetryentails disorder of the Ln atoms; in a further form of lowersymmetry Pn, (pyH)Ln3O(NO3)2(LH)2·2MeCN·xH2O·ydmso·1.5py·MeOH (7Ln, Ln = La, Ce), with no imposed crystallographic symmetry, some disorder persists, but none is found in the crystallographically unrelated form of 8Pr, Pr3O(NO3)(LH)2·16H2O·2MeCN·5py. Ln4(OH)(NO3)3(L)2·8dmf·2dmso·3H2O (10Ln, Ln = Pr...Gd, previously defined for Nd) has a square-planar Ln4O array sandwiched between a pair of L ligands, with a similar form found for Ln4O(ClO4)2(L2)·xdmf·yH2O (11Ln, Ln = La...Nd).

Various 2- and 3-thienylmethylamino-substituted cobalt(III) cage amine complexes, prepared with the objective of obtaining cage-functionalized polythienyls, have been found to be resistant to oxidative polymerization by both electrochemical and chemical procedures. X-ray structure determinations indicate that there is negligible perturbation of the physical dimensions of the thiophene moieties by the cage substituents and thus that the resistance to polymerization must be associated with the high positive charge carried by these substituents.

Structural characterisation of a number of hydrated solids containing chiral, kinetically inert [Co(A–A)3]3+ cations (A–A = 2,2′-bipyridine, 1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine) and chiral, kinetically labile [Ln(dipic)3]3– anions (Ln = La, Eu, Tb, Ho, Er, Lu, Y, though not for all cobalt cations; dipic = dipicolinate = pyridine-2,6-dicarboxylate) show a remarkable range of associations between the lattice components, though all are racemic arrays. Analysis of the structures in terms of short interatomic contacts between the components shows that, whereas numerous contacts of the heteroaromatic ligands do occur, very few define an arrangement which could be truly termed “π-stacking” where the rings are closely parallel and atom overlaps in projection are substantial. Water is important in the highly hydrated lattice structures, not only because of hydrogen-bonding interactions with itself and carboxylate-O atoms but also because of its interactions with the aromatic units. The family [Co(bipy)3][Ln(dipic)3]·~13H2O are essentially isomorphous for the full range of Ln plus Y (triclinic, P\bar{1}, a = 12.3, b = 14.3, c = 16.5 A, α = 94, β = 94, γ = 108 ˚, Z = 2). Among the heavier lanthanides, the potential symmetry of the anion/cation combination is realised in the trigonal space group P\bar{3}, both species lying together as an ion-pair, disposed on the trigonal axis for [Co(phen)3][Ln(dipic)3]·22H2O (Ln = Eu, Er; a = 15.2, c = 16.8 A, Z = 2).

Reactions of the transition metal halide complexes [MXL2(Cp)] (M = Fe, X = I, L2 = dppe; M = Ru, X = Cl, L = PPh3; M = Os, X = Br, L = PPh3; Cp = η-C5H5) with the alkynol HC≡CCH(OH)(Fc) (1) (Fc = f...

Ruthenium half-sandwich complexes are central in a wide range of diverse applications in the field of organometallic chemistry. As such, exploration of their preparation and reactivity is crucial for development of their chemistry. Herein, we present alternative synthetic methods for the preparation of Cp*Ru(dppm)Cl, Cp*Ru(dppe)Cl, Cp*Ru(dppf)Cl, [Cp*Ru(COD)(MeCN)]BF4, and [Cp*Ru(bpy)(MeCN)]BF4 (dppm = 1,2-bis(diphenylphosphino)methane; dppe = 1,2-bis(diphenylphosphino) ethane; dppf = 1,2-bis(diphenylphosphino)ferrocene; COD = 1,5-cyclooctadiene; bpy= 2,2′-bipyridine), starting from the easily accessible [Cp*Ru(η6-C10H8)]BF4. The single-crystal X-ray structure determinations for [Cp*Ru(COD)(MeCN)]BF4, and [Cp*Ru(bpy)(MeCN)]BF4 are also presented.

N-(4′-carboxyphenyl)-2,5-di(2″-thienyl)pyrrole has been efficiently prepared by the Knorr–Paal condensation of 1,4-di(2′-thienyl)butane-1,4-dione with benzocaine(ethyl-4-aminobenzoate), giving N-(ethyl-4′-benzoate)-2,5-di(2″-thienyl)pyrrole, followed by saponification to give the desired acid. Both new compounds are electropolymerizable, and the polymer films stable to repetitive cycling up to +1.2 V Vs Ag/AgCl.

The synthesis and single-crystal x-ray structure determination of two new trinuclear metal complexes is detailed. In these we utilise the appended iminodiacetate substituents, in [Co(CH3)NH(CH2CO2H)2sar]3+, to act as a focus for coordination of other metal ions. Thus, we have made complexes of Cu and Ni utilising the basic carbonates of these metals and [Co(CH3){N(CH2CO2H)2}sar]3+ (CoL2) which gave rise to ((CoL2–2H+)2M), M = Cu and Ni. The electrochemical study of the latter was inconclusive and provides the impetus for further study.

The pendant bipyridyl moiety of transition metal σ-acetylide complexes incorporating the 5-ethynyl-2,2′-bipyridine moiety provides a site of chelation for additional metal centers and facile access to multinuclear complexes as model systems for organometallic “molecular wires”. The mononuclear complexes [CpRu(CO)2(C2bpy)] (Cp = C5H5, C5Me5) and [RuCl(P∩P)2(C2bpy)] (P∩P = dppm, dppe) have been synthesized and characterized through spectroscopic means, providing context for the synthesis and spectroscopic characterization of the heterometallic coordination complex [RuCl(dppe)2(C2bpy-κ2-N,N′-PdCl2)]. A number of the complexes were further characterized by solid-state X-ray structural determinations. These studies were extended to other metal ligand systems, and the structures of the tris-bidentate ruthenium(II) complex [Ru(bpy)2(5-ethynyl-2,2′-bipyridine)](PF6)2 and gold(I) σ-alkynyl complexes [(PR3)Au(C2bpy)] (PR3 = PEt3, PPh3) are reported.

The metalloamphiphile [Zn(1-decylammonio-8-methylsarcophagine)](ClO4)3·2H2O crystallises in the non-centrosymmetric space group P1 to give a polar crystal, which can be converted to one with a centrosymmetric lattice (space groupI2/a) through deprotonation.

The trimetallic clusters [Ru{sub 3}(CO){sub 10}(dppm)], [Ru{sub 3}(CO){sub 12}] and [RuCo{sub 2}(CO){sub 11}] react with a number of multifunctional secondary phosphine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH{sub 2}CH{sub 2}PHPh ({double_bond}LH{sub 2}), gave two products under various conditions which have been characterized by spectroscopic and crystallographic means. These two complexes [Ru{sub 3}({mu}dppm)(H)(CO){sub 7}(LH)] and [Ru{sub 3}({mu}-dppm)(H)(CO){sub 8}(LH)Ru{sub 3}({mu}-dppm)(CO){sub 9}], show the versatility of the ligand, with it chelating in the former and bridging two Ru{sub 3} units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic data which are consistent with the presence of diastereoisomers. In the case of [Ru{sub 3}(CO){sub 12}] the reaction with LH{sub 2} gave a poor yield of a tetranuclear butterfly cluster, [Ru{sub 4}(CO){sub 10}(L){sub 2}], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related ligand, HSCH{sub 2}CH{sub 2}AsMe(C{sub 6}H{sub 4}CH{sub 2}OMe), reacted with [RuCo{sub 2}(CO){sub 11}] to give a low yield of the heterobimetallic Ru-Co adduct, [RuCo(CO){sub 6}(SCH{sub 2}CH{sub 2}AsMe(C{sub 6}H{sub 4}CH{sub 2}OMe))], which appears to be the onlymore » one of its type so far structurally characterized. The secondary phosphine, HPMe(C{sub 6}H{sub 4}(CH{sub 2}OMe)) and its oxide HP(O)Me(C{sub 6}H{sub 4}(CH{sub 2}OMe)) also react with the cluster [Ru{sub 3}(CO){sub 10}(dppm)] to give carbonyl substitution products, [Ru{sub 3}(CO){sub 5}(dppm)({mu}{sub 2}-PMe(C{sub 6}H{sub 4}CH{sub 2}OMe)){sub 4}], and [Ru{sub 3}H(CO){sub 7}(dppm)({mu}{sub 2},{eta}{sup 1}P({double_bond}O)Me(C{sub 6}H{sub 4}CH{sub 2}OMe))]. The former consists of an open Ru{sub 3} triangle with four phosphide ligands bridging the metal-metal bonds; the latter has the O atom symmetrically bridging one Ru-Ru bond, the P atom being attached to a non-bridged Ru atom.« less

Syntheses of the array of heterobimetallic complexes [(OC)3M(μ-PPh2)2(μ-O-C(CHMe(CH2)2PPh2)RhL], M = Cr, Mo, W, L = tBuNC, are described, extending the previous study of the counterpart array for L = CO. A single crystal X-ray structure determination is reported for the M = Mo adduct, enabling comparison with its previously reported L = CO counterpart, for which an improved redetermination is also reported. In the present complex the tBuNC ligand is found to be much more weakly bound (Rh-C 2.026(5) A) than the carbonyl group it displaces (Rh-C 1.945(2) A) with concomitant minor impact on the remainder of the rhodium ambience.

The reaction of the binuclear rhodium complex [(η−C5H5)2Rh2(μ-CO)(μ-η1:η1-C2(CF3)2)] with a series of dichalcogenides, R2E2 (E = S, Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations) has provided mixtures of complexes, the majority of which have been characterized by standard spectroscopic techniques. These complexes arise as a consequence of carbonyl substitution followed by chalcogen-chalcogen bond cleavage giving [(η−C5H5)2Rh2(μ-ER)2(μ-η1:η1-C2(CF3)2)], possibly concomitant with CO insertion into a Rh-C2(CF3)2 bond of the product in some cases, giving [(η−C5H5)2Rh2(CO)(μ-ER)2(μ-η1:η1-C2(CF3)2C(O))] (E = Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations). In the case of Te2R2 the dichalcogenide products have been structurally characterized for the carbonyl insertion product (for R = Et) and the simple cleavage case (for R = i-Pr). In both, the putative m-symmetry is broken by substituent dispositions and, in the R = Et adduct, torsion in the fluorocarbon skeleton.

A series of complexes with π-conjugated carbon chains terminated by bipyridyl moieties has been prepared. These allenylidene complexes were derived from 9-hydroxy-9-ethynyl-4,5-diazafluorene, the preparation of which is reported; the new allenylidene complexes are highly colored with the cumulated carbon chain terminating in a bipyridyl unit providing a site for further coordination. The synthesis, characterization, and X-ray structure determination of trans-[MCl(P∩P)2═C═C═(4,5-diazafluoren-9-yl)]PF6 (M = Ru, P∩P = bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,2-bis(dimethylphosphino)ethane (dmpe); M = Os, P∩P = dppm) are described. The effect of the variation in metal and ligand on electronic and electrochemical characteristics of these complexes has been investigated by using UV–vis, solution electrochemistry, and a combination of these techniques in spectroelectrochemical experiments. DFT calculations have been performed on trans-[RuCl(P∩P)2═C═C═(4,5-diazafluoren-9-yl...

FePt nanoparticles have been assembled on the surface of MCM-41 silicates. The incorporation resulted in highly dispersed particles. Under thermal treatment for 1 h at temperatures up to 560 °C, no signs of agglomeration occurred. The silicates have also been used as a template to assist in the solution synthesis of FePt particles. The resultant particles were distributed over the surface and possibly inside the silcate pores with a range of sizes (3−10 nm).