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The formal cycloaddition adduct of 1,4-benzoquinone with two equivalents of cyclopentadiene is a scaffold with two non-conjugated alkenes. Both alkenes undergo endo [4+2] cycloaddition with a diene to form a rigid U-shaped molecular cleft. Here we show experimental, computational and structural evidence that π interactions between the alkenes affect structural rigidity, Diels-Alder reactivity, cleft formation and host-guest capture. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Structural characterisation of a further series of crystalline solids in which [Ln(dipic)3]3− anions (dipic = pyridine-2,6-dicarboxylate; Ln = La, Gd) are accompanied by chiral Co(iii)-containing cations provides new examples of layered lattices where sheets of anions and (cations + water) alternate. Δ,Λ-[Co(en)3]3+ (en = ethane-1,2-diamine) forms crystals where, depending on the degree of hydration, the cation sheets are either homo- or heterochiral but the anion sheets are always heterochiral. Δ-[Co(en)3]3+ provides lattices where the anion sheets remain heterochiral, resulting in unusual solids containing a single enantiomer of the cation along with both enantiomers of the chiral anion, rather than two diastereomeric crystals containing the separate anions. Classical resolution of the anions only appears to occur in the presence of a functionalised cage amine complex cation, Δ-[Co((NO2)2sar)]3+ (sar = sarcophagine = 3,6,10,13,16,19-hexa-azabicyclo[6.6.6]icosane) which gives crystals in which direct H-bonding interactions between the cations and anions are surprisingly limited and the success of the resolution requires consideration of a variety of other factors. [ABSTRACT FROM AUTHOR]

Extended structural studies, largely determinations at ~150 K, of the family of hydrates of [Co(NH3)6][Ln(dipic)3] (Ln=La-Lu, and Y; dipic=dipicolinate=pyridine-2,6-dicarboxylate) have provided detailed evidence of the nature of the interactions between the formally achiral cation and the chiral anions. They also provide a reference point for consideration of related systems incorporating chiral cations with and without the capacity to act as H-bond donors. [ABSTRACT FROM AUTHOR]

Two new N-heterocyclic carbene (NHC) ligands bearing 2-morpholino and 2-piperidinyl naphthyl wingtips were synthesised (2-SIMorNap and 2-SIPipNap). Nuclear magnetic resonance studies, in conjunction with crystal structures and derivatisation of the NHC salts using a chiral counteranion, revealed that the ligand wingtips are oriented anti with respect to each other. From the free carbene, palladium, ruthenium and iridium complexes were prepared. NHC–iridium dicarbonyl complexes were made in order to extract the TEP values for these ligands. The study showed that these NHC ligands are more electron-donating than normal, aryl-substituted NHCs. The palladium complexes were tested in representative Suzuki–Miyaura cross-coupling reactions and compared to the state of the art systems. Ruthenium-catalysed ring-closing metathesis with these ligands was also performed. It was found that Grubbs’ 2nd generation catalyst incorporating 2-SIPipNap did not initiate at room temperature and required heating for RCM to occur. [ABSTRACT FROM AUTHOR]

While attempting to prepare a series of cationic NHC-Ir complexes of general formula [(NHC)Ir(COD)]+ via the silver salt metathesis reaction of its precursor (NHC)Ir(COD)Cl in dichloromethane, we unexpectedly synthesized [(μ-Cl){(2,7-SICyNap)Ir(COD)}·{Ag(OTf)}], a chloride-bridged Ir-Ag adduct. This result led us to investigate the chloride abstraction from the (NHC)Ir(COD)Cl system in detail. We show how the outcome of this ubiquitous reaction is dependent on a fine balance between the nucleophilicity of the weakly coordinating anion (WCA) and the polarity/coordinating ability of the reaction medium. A frequently encountered alternative to using silver salts is also presented and compared. The experimental difference in the reactivities of cationic catalysts in a representative intramolecular hydroamination reaction shows how a cationic Ir-Ag adduct can fail to deliver the reaction product through what appears to be a stabilization of the catalytically inactive iridium-silver intermediate by the educt. [ABSTRACT FROM AUTHOR]

Reactions between [Ru(C CC CH)(dppe)Cp ∗ ] and [M 2 (NCMe) x (dppm) 2 ] 2+ (M = Cu, x = 4; Ag, x = 2) have given complexes containing M 3 (μ-dppm) 3 clusters attached to one or two C CC C[Ru(dppe)Cp ∗ ] groups. Single crystal X-ray studies are recorded for [{M 3 (μ-dppm) 3 }{μ 3 -C CC C[Ru(dppe)Cp ∗ ]}](BF 4 ) 2 ·nS (M = Cu, Ag) [isomorphous (orthorhombic) for S = (ill-defined) acetone]. A different (triclinic) polymorph has also been defined for M = Ag, nS = 5THF. Together with [{Cu 3 (μ-dppm) 3 }{μ 3 -C CC C[Ru(dppe)Cp ∗ ]} 2 ]PF 6 ·4Me 2 CO, the structures definitively confirm the complexes as clear examples of mono- or bis-diyndiyl-M 3 systems, devoid of close approaches to the vacant M 3 faces of the former by counterions in the case of their acetone solvates, except in the case of the BF 4 counterion in the AgBF 4 /thf solvate. Cyclic voltammetric studies suggest that there are only weak electronic interactions between the ruthenium centres in the bis(diynyl) complexes, consequent upon weak overlaps between the carbon chain and the M 3 (μ-dppm) 3 clusters, as confirmed by DFT calculations on model complexes [{M 3 (μ-dHpm) 3 }{C CC C[Ru(dHpe)Cp]} n ] 3-n [n = 1, 2; dHpm = CH 2 (PH 2 ) 2 , dHpe = H 2 P(CH 2 ) 2 PH 2 ]. The complexes [Ag 3 Cl 2 (dppm) 3 ]PF 6 , [M 3 (μ-dppm) 3 (X){μ 3 -C CC C[Re(CO) 3 (Bu t 2 -bpy)]}]PF 6 (M = Cu, X = C CC C[Re(CO) 3 (Bu t 2 -bpy)]; M = Ag; X = Cl), [Ag 6 (μ-dppm) 4 {C CC C[Re(CO) 3 (Bu t 2 -bpy)]} 4 ](PF 6 ) 2 have also been prepared and structurally characterised. In the M 3 clusters, some asymmetry in the attachment of at least one of the μ 3 ligands is apparent, which results from interactions with solvate molecules. [ABSTRACT FROM AUTHOR]

The preparation of discrete tetranuclear lanthanide/alkali metal (Ae) assemblies bearing a tribenzoylmethane ligand (LH) is discussed. These assemblies have the general formula [Ln(Ae·HOEt)(L)4]2, where Ln3+ = Gd3+, Tb3+, Dy3+, Ho3+and Ae+ = Na+, K+, Rb+. The coordination geometries of the lanthanide species were analyzed and compared, revealing a trend between an eight-coordinate square antiprism and triangular dodecahedron dependent on the nature of lanthanide, alkali metal, and lattice solvent. The potassium-containing analogs were also analyzed for their magnetic susceptibility. [ABSTRACT FROM AUTHOR]

Single crystal X-ray studies of p-t-butylcalix[10]arene·2dmso·7H2O (1) and [NMe4][p-t-butylcalix[9]arene-H]·2dmso·H2O (2), provide new data on these large macrocycles and their conformations, that of 2 being the first where an encapsulated [NMe4]+ cation is present, while 1 contains the neutral ligand. Both were obtained as crystalline products of the reactions of the calixarenes with tetramethylammonium hydroxide after prolonged standing. The structure of [NEt4][calix[4]arene-H], in which the cation approaches inclusion in the shallow cone of the anion, is also defined and compared with various other alkylammonium derivatives of calixarenes as well as that of p-t-butylcalix[9]arene. [ABSTRACT FROM AUTHOR]

While a multitude of studies have appeared touting the use of molecules as electronic components, the design of molecular switches is crucial for the next steps in molecular electronics. In this work, single-molecule devices incorporating spiropyrans, made using break junction techniques, are described. Linear spiropyrans with electrode-contacting groups linked by alkynyl spacers to both the indoline and chromenone moieties have previously provided very low conductance values, and removing the alkynyl spacer has resulted in a total loss of conductance. An orthogonal T-shaped approach to single-molecule junctions incorporating spiropyran moieties in which the conducting pathway lies orthogonal to the molecule backbone is described and characterized. This approach has provided singlemolecule conductance features with good correlation to molecular length. Additional higher conducting states are accessible using switching induced by UV light or protonation. Theoretical modeling demonstrates that upon (photo)chemical isomerization to the merocyanine, two cooperating phenomena increase conductance: release of steric hindrance allows the conductance pathway to become more planar (raising the mid-bandgap transmission) and a bound state introduces sharp interference near the Fermi level of the electrodes similarly responding to the change in state. This design step paves the way for future use of spiropyrans in single-molecule devices and electrosteric switches., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)

Chiral, cationic NHC-iridium complexes are introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes. The catalysts show high activity in the construction of a range of 5- and 6-membered N-heterocycles, which are accessed in excellent optical purity, with various functional groups being tolerated with this system. A major deactivation pathway is presented and eliminated by using alternative reaction conditions. A detailed experimental and computational study on the reaction mechanism is performed providing valuable insights into the mode of action of the catalytic system and pointing to future modifications to be made for this catalytic platform., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Trinuclear lanthanoid clusters have been synthesised and investigated as toroidal spin systems. A pyridyl functionalised β-diketonate, 1,3-bis(pyridin-2-yl)propane-1,3-dione (o-dppdH) has been used to synthesise a family of clusters of the form [Dy3(OH)2(o-dppd)3Cl2(H2O)4]Cl2·7H2O (1), [Tb3(o-dppd)3(μ3-OH)2(CH3CH2OH)3Cl3][Tb3(o-dppd)3(μ3-OH)2(H2O)(CH3CH2OH)2Cl3]Cl2·H2O (2), [Ho3(OH)2(o-dppd)3Cl(H2O)5]Cl3·3H2O (3) and [Er3(OH)2(o-dppd)3Cl2(H2O)3(CH3OH)]Cl2·3H2O·CH3OH (4). Despite the previous occurrence of this structural motif in the literature, these systems have not been widely investigated in terms of torodic behaviour. Magnetic studies were used to further characterise the complexes. DC susceptibility studies support weak antiferromagnetic exchange in the complexes. Slow magnetic relaxation behaviour is observed in the dynamic AC magnetic studies for complex 1. Theoretical studies predict that complex 1 and 3 have a non-magnetic ground state based on a toroidal arrangement of spins. Changes to the coordination environment in 2 do not support a toroic spin state. The prolate nature of the ErIII centres in complex 4 and large transverse anisotropy do not support the toroidal arrangement of lanthanoid spins in the complex.

Herein, we report a Rh(II)-catalyzed reaction between 1-tosyl-1,2,3-triazoles and halohydrins to provide 2,6-substituted 3,4-dihydro-2 H -1,4-oxazines under basic conditions. The reaction is proposed to undergo a rhodium carbenoid 1,3-insertion into O-H followed by an annulation. The scope includes phenyl or alkenyl C4-substituted triazoles and a range of halohydrins using catalytic Rh 2 Oct 4 and K 2 CO 3 . A synthesis of the antimicrobial natural product (±)-chelonin C is also reported using this novel methodology.

Two previously reported bis-indole alkaloids, echinosulfone A and echinosulfonic acid B, have been isolated for the first time from a Western Australian marine sponge, Crella sp. (order: Poecilosclerida, family: Crellidae). Single-crystal X-ray diffraction of a decomposition product of echinosulfone A prompted our investigation and subsequent structure reassignment of the echinosulfonic acid natural product family, which we report here. The reassignments are supported by analysis of 1D and 2D NMR data, MS fragmentation, and DFT calculations of 13 C NMR shifts.

The etiology of fungal pathogenesis of grains is critical to global food security. The large number of orphan biosynthetic gene clusters uncovered in fungal plant pathogen genome sequencing projects suggests that we have a significant knowledge gap about the secondary metabolite repertoires of these pathogens and their roles in plant pathogenesis. Cytochalasans are a family of natural products of significant interest due to their ability to bind to actin and interfere with cellular processes that involved actin polymerization; however, our understanding of their biosynthesis and biological roles remains incomplete. Here, we identified a putative polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) gene cluster ( phm ) that was upregulated in the pathogen Parastagonospora nodorum during its infection on wheat. Overexpression of the transcription factor gene phmR encoded in the phm gene cluster resulted in the production of two leucine-derived cytochalasans, phomacins D and E ( 1 and 2 , respectively), and an acetonyl adduct phomacin F. Heterologous expression of the PKS-NRPS gene phmA and the trans -enoyl reductase (ER) gene phmE in Aspergillus nidulans resulted in the production of a novel 2-pyrrolidone precursor prephomacin. Reverse genetics and wheat seedling infection assays showed that Δ phmA mutants exhibited significantly reduced virulence compared to the wild type. We further demonstrated that both 1 and 2 showed potent actin polymerization-inhibitory activities and exhibited potentially monocot-specific antigerminative activities. The findings from this study have advanced our knowledge based on the biosynthesis and biological roles of cytochalasans, the latter of which could have significant implications for our understanding of the molecular mechanisms of fungus-plant interactions.

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 first approaches to the 10'-anthronyl-2-anthraquinone skeleton have been devised, allowing two syntheses of the marine natural product albopunctatone. Both routes involve regioselective addition of a nucleophilic masked anthraquinone to a protected chrysazin derivative; the best affords albopunctatone in five steps and 35% overall yield. Albopunctatone exhibits potent inhibitory activity against Plasmodium falciparum and negligible toxicity to a range of other microbial pathogens and mammalian cells.

The monocation product of the oxidative condensation-cyclization between two mol-ecules of pyridine-2-carbaldehyde and one mol-ecule of CH 3 NH 2 ·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridinium, was isolated in the presence of metal ions as bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] tetra-iodo-cadmate, (C 13 H 12 N 3 ) 2 [CdI 4 ], (I), and the mixed chloride/nitrate salt, bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] 1.5-chlor-ide 0.5-nitrate trihydrate, 2C 13 H 12 N 3 + ·1.5Cl - ·0.5NO 3 - ·3H 2 O, (II). Hybrid salt (I) crystallizes in the space group P 2 1 / n with two [ L ] 2 [CdI 4 ] mol-ecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetra-halometallate anions are stacked parallel to the ab plane. Anti-parallel L + cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetra-hedral CdI 4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water mol-ecules runs parallel to a column of stacked cations.

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 3 . The reactive 4a cyclizes spontaneously to a [4]ferrocenophane with buta-1,3-diene handle (5) or in the presence of AlCl 3 to a [3]ferrocenophane with propene handle (6). Structure assignments are supported by X-ray crystallography and NMR spectroscopy, and mechanisms are proposed. Electrochemical behavior of the compounds was investigated with cyclic voltammetry, and assignments of the redox processes were carried out with the aid of density functional theory calculations. The synthesized compounds and demonstrated transformations represent useful tools for preparation of materials for charge-transport studies in metal-molecule-metal junctions.

β-Triketonates have been recently used as chelating ligands for lanthanoid ions, presenting unique structures varying from polynuclear assemblies to polymers. In an effort to overcome low solubility of the complexes of tribenzoylmethane, four β-triketones with higher lipophilicity were synthesised. Complexation reactions were performed for each of these molecules using different alkaline bases in alcoholic media. X-ray diffraction studies suggested that the ligands were undergoing decomposition under the reaction conditions. This is proposed to be caused by in situ retro-Claisen condensation reactions, consistent with two examples that have been reported previously. The lability of the lanthanoid cations in the presence of a varying set of potential ligands gave rise to structures where one, two, or three of the molecules involved in the retro-Claisen condensation reaction were linked to the lanthanoid centres. These results, along with measurements of ligand decomposition in the presence of base alone, suggest the solvent used will modulate the impact of the retro-Claisen condensation in these complexes.

Isomorphous β-triketonate-based lanthanoid polymers containing tris(4-methylbenzoyl)methanide (mtbm) and Rb+ with formula {[Ln(Rb)(mtbm)4]2}n (Ln = Eu3+ and Nd3+) have been synthesised and structurally characterised. The photophysical properties for the Nd3+ complex presented relatively long lifetimes and high quantum yields in comparison with analogous β-diketonate complexes. Mixed lanthanoid complexes were also formed and their luminescence properties studied, with effective sensitisation of the 4F3/2 of Nd3+via the 5D0 of Eu3+, which is to the best of our knowledge the first example of Eu3+ to Nd3+ sensitisation in a structurally defined coordination complex or polymer.

A novel chiral disulfoxide ligand pair bearing fluorine atoms at the 6 and 6' position of its atropisomeric backbone, ( M, S, S)- and ( P, S, S)- p-Tol-6F-BIPHESO, was synthesized. Complexation to a rhodium(I) precursor gave rise to μ-Cl- and μ-OH-bridged rhodium dimer complexes incorporating the new ( M, S, S)- p-Tol-6F-BIPHESO ligand, while its sibling ( P, S, S)- p-Tol-6F-BIPHESO was not complexed efficiently to the rhodium precursor. The performance of this disulfoxide ligand [( M, S, S)- p-Tol-6F-BIPHESO] in catalysis was tested in both 1,4- and 1,2-addition reactions of arylboronic acids. We show that addition to both cyclic and acyclic enones as well as N-tosylarylimines proceeds with high yields and high enantioselectivities to give the corresponding products. The synthesis of enantiomerically pure p-Tol-6F-BIPHESO is straightforward and inexpensive which, together with the high catalytic performance and wide substrate scope for these addition reactions, makes it a very attractive alternative to more classical chiral ligand entities.

The reaction of the β-triketonate ligands tris(4-methylbenzoyl)methanide and tribenzoylmethanide with the trivalent lanthanoids Eu 3+ , Er 3+ , and Yb 3+ in the presence of Cs + afforded polymeric structures where the repeating units are represented by bimetallic tetranuclear assemblies of formulation {[Ln(Cs)(β-triketonate) 4 ] 2 } n . The only exception is the structure formed by the reaction of tris(4-methylbenzoyl)methanide, Yb 3+ , and Cs + , which yielded a polymeric assembly where the repeating units are mononuclear Yb 3+ complexes bridged by Cs + cations. Photophysical measurements on the obtained materials confirmed efficient sensitization from the ligand excited states to the 4f* excited states of the three lanthanoids. According to transient absorption data, Er 3+ and Yb 3+ are sensitized via energy transfer from the triplet state of the β-triketonate ligands. On the other hand, energy transfer to Eu 3+ seems to occur via an alternative pathway, possibly directly via the singlet state or through ligand to metal charge transfer states. The emission measurements confirm efficient sensitization for all three lanthanoids and bright near-infrared emission for Er 3+ and Yb 3+ , a characteristic that seems to be linked to the specific chemical structure of the β-triketonate ligands.

Metal complexes are receiving increased attention as molecular wires in fundamental studies of the transport properties of metal|molecule|metal junctions. In this context we report the single-molecule conductance of a systematic series of d 8 square-planar platinum(ii) trans-bis(alkynyl) complexes with terminal trimethylsilylethynyl (C[triple bond, length as m-dash]CSiMe 3 ) contacting groups, e.g. trans-Pt{C[triple bond, length as m-dash]CC 6 H 4 C[triple bond, length as m-dash]CSiMe 3 } 2 (PR 3 ) 2 (R = Ph or Et), using a combination of scanning tunneling microscopy (STM) experiments in solution and theoretical calculations using density functional theory and non-equilibrium Green's function formalism. The measured conductance values of the complexes (ca. 3-5 × 10 -5 G 0 ) are commensurate with similarly structured all-organic oligo(phenylene ethynylene) and oligo(yne) compounds. Based on conductance and break-off distance data, we demonstrate that a PPh 3 supporting ligand in the platinum complexes can provide an alternative contact point for the STM tip in the molecular junctions, orthogonal to the terminal C[triple bond, length as m-dash]CSiMe 3 group. The attachment of hexyloxy side chains to the diethynylbenzene ligands, e.g. trans-Pt{C[triple bond, length as m-dash]CC 6 H 2 (Ohex) 2 C[triple bond, length as m-dash]CSiMe 3 } 2 (PPh 3 ) 2 (Ohex = OC 6 H 13 ), hinders contact of the STM tip to the PPh 3 groups and effectively insulates the molecule, allowing the conductance through the full length of the backbone to be reliably measured. The use of trialkylphosphine (PEt 3 ), rather than triarylphosphine (PPh 3 ), ancillary ligands at platinum also eliminates these orthogonal contacts. These results have significant implications for the future design of organometallic complexes for studies in molecular junctions.

Large metal-oxo clusters consistently assume spherical or regular polyhedral morphologies rather than high-aspect-ratio structures. Access to elongated core structures has now been achieved by the reaction of lanthanoid salts with a tetrazole-functionalized calixarene in the presence of a simple carboxylate co-ligand. The resulting Ln19 and Ln12 clusters are constructed from apex-fused Ln5O6 trigonal bipyramids and are formed consistently under a range of reaction conditions and reagent ratios. Altering the carboxylate co-ligand structure reliably controls the cluster length, giving access to a new class of rod-like clusters of variable length.

[RuCl(arene)(μ-Cl)]2 dimers were treated in a 1:2 molar ratio with sodium or thallium salts of bis- and tris(pyrazolyl)borate ligands [Na(Bp(Br3))], [Tl(Tp(Br3))], and [Tl(Tp(iPr, 4Br))]. Mononuclear neutral complexes [RuCl(arene)(κ(2)-Bp(Br3))] (1: arene=p-cymene (cym); 2: arene=hexamethylbenzene (hmb); 3: arene=benzene (bz)), [RuCl(arene)(κ(2)-Tp(Br3))] (4: arene=cym; 6: arene=bz), and [RuCl(arene)(κ(2)-Tp(iPr, 4Br))] (7: arene=cym, 8: arene=hmb, 9: arene=bz) have been always obtained with the exception of the ionic [Ru2 (hmb)2-(μ-Cl)3][Tp(Br3)] (5'), which formed independently of the ratio of reactants and reaction conditions employed. The ionic [Ru-(CH3OH)(cym)(κ(2)-Bp(Br3))][X] (10: X=PF6, 12: X=O3SCF3) and the neutral [Ru(O2CCF3)(cym)(κ(2)-Bp(Br3))] (11) have been obtained by a metathesis reaction with corresponding silver salts. All complexes 1-12 have been characterized by analytical and spectroscopic data (IR, ESI-MS, (1)H and (13)C NMR spectroscopy). The structures of the thallium and calcium derivatives of ligand Tp(Br3), [Tl(Tp(Br3))] and [Ca(dmso)6][Tp(Br3)]2 ⋅2 DMSO, of the complexes 1, 4, 5', 6, 11, and of the decomposition product [RuCl(cym)(Hpz(iPr, 4Br))2][Cl] (7') have been confirmed by using single-crystal X-ray diffraction. Electrochemical studies showed that 1-9 and 11 undergo a single-electron Ru(II) →Ru(III) oxidation at a potential, measured by cyclic voltammetry, which allows comparison of the electron-donor characters of the bis- and tris(pyrazol-1-yl)borate and arene ligands, and to estimate, for the first time, the values of the Lever EL ligand parameter for Bp(Br3), Tp(Br3), and Tp(iPr, 4Br). Theoretical calculations at the DFT level indicated that both oxidation and reduction of the Ru complexes under study are mostly metal-centered with some involvement of the chloride ligand in the former case, and also demonstrated that the experimental isolation of the μ(3)-binuclear complex 5' (instead of the mononuclear 5) is accounted for by the low thermodynamic stability of the latter species due to steric reasons., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN : ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ν(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ν(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra.

Addition of 1-alkyl-3-methylimidazolium (C(n)-mim) cations 3-5 to a mixture of bis-phosphonium cation 2 and sodium p-sulfonatocalix[4]arene (1) in the presence of lanthanide ions results in the selective binding of an imidazolium cation into the cavity of the calixarene. The result is a multi-layered solid material with an inherently flexible interplay of the components. Incorporating ethyl-, n-butyl- or n-hexyl-mim cations into the multi-layers results in significant perturbation of the structure, the most striking effect is the tilting of the plane of the bowl-shaped calixarene relative to the plane of the multi-layer, with tilt angles of 7.2, 28.9 and 65.5 degrees , respectively. The lanthanide ions facilitate complexation, but are not incorporated into the structures and, in all cases, the calixarene takes on a 5- charge, with one of the lower-rim phenolic groups deprotonated. ROESY NMR experiments and other (1)H NMR spectroscopy studies establish the formation of 1:1 supermolecules of C(n)-mim and calixarene, regardless of the ratio of the two components, and indicate that the supermolecules undergo rapid exchange on the NMR spectroscopy timescale.

In extension of recent synthetic and crystallographic studies of adducts of silver(I) oxyanion salts with uni- and bi-dentate nitrogen-donor ligands, AgX : L (1 : n), a parallel series of complexes formed with silver(I) trifluoromethanesulfonate ('tfs', 'triflate') has been similarly defined, showing rather more divergence from tendencies established with the previous ClO(4), NO(3), F(3)CCO(2) core arrays than might be expected from basicity arguments. Thus, while silver triflate crystallised from neat base forms 1 : 2 mononuclear adducts with 2,4,6-trimethylpyridine and quinoline which comprise essentially linear two-coordinate [LAgL](+) cations, perturbed by approaches of the anions, 1 : 2 adducts obtained similarly from pyridine and 2-methylpyridine are [L(2)Ag(mu-tfs)(2)AgL(2)] dimers, with central four- and eight-membered rings arising from mu-OSO(2)CF(3) and extended mu-(O,O'SOCF(3)) anion bridging modes, respectively. With piperidine, a single-stranded polymer reminiscent of the arrays [(pip)(2)AgX](infinity/infinity), X = Cl, NCS, is formed, the triflate bridging through two of its oxygen atoms, rather than via a single atom bridge. With 2- and 4-cyanopyridine, the former a 1 : 1 adduct (being an acetonitrile solvate (MeCN coordinated)), and the latter 1 : 2, both are more complex structures in which the nitrile functionalities now coordinate weakly. The 1 : 2 adduct with 2-acetylpyridine parallels its perchlorate analogue, the ligands being bidentate in a mononuclear complex [L(2)AgOSO(2)CF(3)], while adducts of 2,9-dimethylphenanthroline and 2,2'-biquinolyl, both acetonitrile monosolvates, take the form [LAg(NCMe)]tfs. Agtfs : dpk (8 : 8)(infinity/infinity).EtOH ('dpk' = bis(2-pyridyl)ketone) is a complex polymer. The nature of the interactions is explored by way of spectroscopy (IR, NMR and ESI MS) and a density functional theory approach.

Lower rim O-methyl, -n-butyl, and n-octadecyl calix[4]arenes bearing p-phosphonic acid groups on the upper rim have been prepared in high yield, compounds 12-14. Where possible the compounds have been characterized in the solid state using X-ray diffraction, or as the precursor phosphate esters or a cesium salt. The cone conformation ethyl phosphate ester for the octadecyl compound crystallizes in a bi-layer 39.1 A thick which approaches the 40 A of biological membranes. The 1,3-alternate cone conformation of the cesium salt of the O-methyl phosphonic acid has a metal ion coordinated to two methoxy groups, four O-P (two from neighboring calixarenes), and two eta(3)-C(3) moieties from two 1,3-disposed aromatic rings. MALDI-TOF spectra of compounds 12-14 show successive peaks corresponding to 15, 33 and 16 calixarene units, which is consistent with the intra-molecular H-bonding capabilities of the di-protic phosphonic acid groups where the calixarenes are arranged into layers, including bilayers.

In toluene fullerene C(70) forms 2:1 complexes with p-benzylcalix[5]arene (1) and p-phenylcalix[5]arene (2), [C(70) subset1(2)].6(C(7)H(8)) and [C(70) subset2(2)].7(C(7)H(8)). The fullerene molecules are completely shrouded by two calix[5]arenes in addition to terminal benzyl groups from other supermolecules, [C(70) subset1(2)], and solvent. Within the capsule-like supermolecules the calixarenes have distinctly different arrangements relative to the principal axis of the fullerene; for [C(70) subset1(2)].6(C(7)H(8)) the oxygen planes of the two calixarenes are skewed by 37.0 and 47.5 degrees , whereas in [C(70) subset2(2)].7(C(7)H(8)) the principal axes of the fullerene and the two encapsulating calixarenes are more closely aligned with the corresponding angles at 9.7 and 8.6 degrees , and features a pentaphenyl inter-calixarene embrace. The Hirshfeld surfaces of these two complexes have been investigated for a detailed understanding of the orientation and nature of interactions of C(70) with the cavitand-type molecules and toluene.

In the presence of lanthanide ions, a Co(III) sepulchrate cation [Co(diHOsar)]3+ and sodium p-sulfonatocalix[4]arene form a 1:1 host-guest complex which is self-assembled into a zeolite-like lattice network comprised of parallel, single stranded helices.

The single-crystal structure of a beta'-copper vanadium bronze, Cu0.63V2O5, has been studied at room temperature and 9.6 K, and compared with that of the beta-sodium vanadium bronze, Na0.33V2O5, structure. No convincing evidence to oppose an assignment of centrosymmetric C2/m symmetry to the structure was identified using the X-ray data. A subsequent convergent beam electron diffraction (CBED) experiment was performed and confirmed the C2/m space group. The oxygen-vanadium atom framework of Cu0.63V2O5 is close to that of Na0.33V2O5. However, in the copper compound the Cu atoms are located in two positions: Cu1 in the 4(i) position with x=0.541, y=0 and z=0.345, and Cu2 in the 8(j) position with x=0.529, y=0.038 and z=0.357. The crystal structure changes little with temperature. Disorder of the Cu ion over two sites is seen at 9.6 K. This suggests that distribution of the Cu atoms over two sites is of a more static than dynamic nature.

Phenyl embraces involving tetraphenylphosphonium cations feature in complexes of p-sulfonatocalix[4]arene where a phenyl ring of a cation is included in the cavity of the calixarene. The overall structures are based on pseudo-polymorphic supramolecular arrays and their formation is templated or induced by lanthanide ions.