The Quasi-Verbal Dispute Between Kripke and 'Frege-Russell'

Traditional descriptivism and Kripkean causalism are standardly interpreted as rival theories on a single topic. I argue that there is no such shared topic, i.e. that there is no question that they can be interpreted as giving rival answers to. The only way to make sense of the commitment to epistemic transparency that characterizes traditional descriptivism is to interpret Russell and Frege as proposing rival accounts of how to characterize a subject’s beliefs about what names refer to. My argument relies on a development of the distinction between speaker’s reference and semantic reference

Attachment of a Ru^II Complex to a Self-Folding Hexaamide Deep Cavitand

We report the design, synthesis and characterization of a new Ru^II metallocavitand that is catalytically active in alkene epoxidation reactions. The elaboration of the resorcin[4]­arene’s aromatic cavity produced a self-folding, deep hexaamide cavitand featuring a single diverging terpyridine (tpy) group installed at its upper rim. The construction of the metallocavitand involved the initial chelation of a Ru^III chloride complex by the tpy ligand followed by the incorporation of 2-(phenylazo)­pyridine (azpy) as an ancillary ligand. The resulting Ru^II chloro complex was converted into the catalytically active aqua counterpart by a ligand exchange process

Exploring the Self-Assembly of Polar Dimeric Capsules Using Molecular Rulers

A homologous series of <i>N,N,N</i>′<i>,N</i>′-tetramethylalkyl-<i>N,N</i>′-dioxides is used to probe the level of guest induced fit attainable in the assembly of a dimeric capsule based on tetraurea benzyl calix[4]pyrrole components. A sensible enhancement of the capsule’s volume was observed in response to guest size for <i>n</i> = 2, 3, and 4. In turn, larger guests adopted folded conformations to adapt to the capsule’s dimensions

Reversible Light-Controlled Cargo Release in Hydrogen-Bonded Dimeric Capsules

We describe the synthesis of three tetra­urea­calix­[4]­arenes having four appended terminal azobenzene groups. In CD₂Cl₂ solution and at millimolar concentration, the thermally equilibrated <i>all</i>-<i>trans</i>-tetraureas dimerize quantitatively, encapsulating one Me₄P⁺ cation. The light-induced isomerization of the <i>all</i>-<i>trans</i> encapsulation complexes produced a plethora of isomeric <i>cis-</i>enriched counterparts displaying a reduction in cavity size. <i>cis</i>-enriched dimers not suitable for the encapsulation of the cation or a solvent molecule are also produced, leading to partial release of the cargo (Me₄P⁺) to the bulk solution. The substitution of the terminal phenyl in the azobenzene groups plays a key role in controlling the amount of released cargo in quantities up to 70%. The switching between the two states (<i>all</i>-<i>trans</i> and <i>cis</i>-enriched capsules) proceeds with no detectable photodegradation, even when it is repeated multiple times

Intermittent compression of <i>N</i>-alkyl-<i>N</i>,<i>N</i>-dimethylamine <i>N</i>-oxides encapsulated in a container with bis[2]catenane topology

<p>We report the encapsulation of a homologous series of <i>N</i>-alkyl-<i>N</i>,<i>N</i>-dimethylamine <i>N</i>-oxides in a molecular container with bis[2]catenane topology. <i>N</i>-oxides with short alkyl chains are co-encapsulated with one solvent molecule. Elongation of the alkyl chain from <i>R</i> = methyl to pentyl produced the progressive compression of the guest. The hexyl <i>N</i>-oxide reduces its compression by being singly encapsulated. Longer <i>N</i>-oxides (<i>R</i> = octyl to decyl) had to fold to adapt to the capsule’s dimensions and also experience a progressive compression. The mechanically interlocked nature of the container and the polar functionalisation of its cavity are responsible for the assembly of encapsulation complexes in solution displaying high packing coefficients (0.65–0.70). The high energy conformations adopted by the alkyl chains of the bound <i>N</i>-oxides are deduced from NMR experiments and molecular modelling studies.</p

Polyatomic Anion Assistance in the Assembly of [2]Pseudorotaxanes

We describe the use of polyatomic anions for the quantitative assembly of ion-paired complexes displaying pseudorotaxane topology. Our approach exploits the unique ion-pair recognition properties exhibited by noncovalent neutral receptors assembled through hydrogen-bonding interactions between a bis-calix[4]­pyrrole macrocycle and linear bis-amidepyridyl-<i>N</i>-oxides. The complexation of bidentate polyatomic anions that are complementary in size and shape to the receptor’s cavity, in which six NH hydrogen-bond donors converge, induces the exclusive formation of four particle-threaded assemblies

Polyatomic Anion Assistance in the Assembly of [2]Pseudorotaxanes

We describe the use of polyatomic anions for the quantitative assembly of ion-paired complexes displaying pseudorotaxane topology. Our approach exploits the unique ion-pair recognition properties exhibited by noncovalent neutral receptors assembled through hydrogen-bonding interactions between a bis-calix[4]­pyrrole macrocycle and linear bis-amidepyridyl-<i>N</i>-oxides. The complexation of bidentate polyatomic anions that are complementary in size and shape to the receptor’s cavity, in which six NH hydrogen-bond donors converge, induces the exclusive formation of four particle-threaded assemblies

Polyatomic Anion Assistance in the Assembly of [2]Pseudorotaxanes

We describe the use of polyatomic anions for the quantitative assembly of ion-paired complexes displaying pseudorotaxane topology. Our approach exploits the unique ion-pair recognition properties exhibited by noncovalent neutral receptors assembled through hydrogen-bonding interactions between a bis-calix[4]­pyrrole macrocycle and linear bis-amidepyridyl-<i>N</i>-oxides. The complexation of bidentate polyatomic anions that are complementary in size and shape to the receptor’s cavity, in which six NH hydrogen-bond donors converge, induces the exclusive formation of four particle-threaded assemblies

Synthesis, Structure, and Binding Properties of Lipophilic Cavitands Based on a Calix[4]pyrrole-Resorcinarene Hybrid Scaffold

We report the synthesis, structural characterization, and binding properties of a series of unprecedented cavitands based on a <i>meso</i>-dodecyl-calix­[4]­pyrrole-resorcin­[4]­arene hybrid scaffold. The reported structural and conformational features of the prepared cavitands are derived from results obtained in solution, solid state, and molecular modeling studies. In the solid state, these cavitands are exclusively observed in the kite <i>C</i>₄ structure and as a racemic mixture of two cyclochiral conformers, which are interconverting fast on the ¹H NMR time scale, according to solution studies. In agreement, molecular modeling studies assign an energy preference for the kite conformer of the cavitands. The polar interior of the synthesized containers allows for the inclusion of a series of pyridine <i>N</i>-oxide derivatives. This results in the formation of 1:1 complexes that are kinetically and thermodynamically highly stable. The putative switching process between the vase and kite forms of these cavitands is investigated in solution by means of variable temperature ¹H NMR experiments. <i>N</i>-Oxide guests that are size and shape complementary to the volume of the cavity of the vase form are also employed to facilitate its emergence. All of the results obtained indicate the existence of a remarkable preference toward the kite conformation both in free and bound calix[4]­pyrrole-based cavitands

Synthesis, Structure, and Binding Properties of Lipophilic Cavitands Based on a Calix[4]pyrrole-Resorcinarene Hybrid Scaffold

We report the synthesis, structural characterization, and binding properties of a series of unprecedented cavitands based on a <i>meso</i>-dodecyl-calix­[4]­pyrrole-resorcin­[4]­arene hybrid scaffold. The reported structural and conformational features of the prepared cavitands are derived from results obtained in solution, solid state, and molecular modeling studies. In the solid state, these cavitands are exclusively observed in the kite <i>C</i>₄ structure and as a racemic mixture of two cyclochiral conformers, which are interconverting fast on the ¹H NMR time scale, according to solution studies. In agreement, molecular modeling studies assign an energy preference for the kite conformer of the cavitands. The polar interior of the synthesized containers allows for the inclusion of a series of pyridine <i>N</i>-oxide derivatives. This results in the formation of 1:1 complexes that are kinetically and thermodynamically highly stable. The putative switching process between the vase and kite forms of these cavitands is investigated in solution by means of variable temperature ¹H NMR experiments. <i>N</i>-Oxide guests that are size and shape complementary to the volume of the cavity of the vase form are also employed to facilitate its emergence. All of the results obtained indicate the existence of a remarkable preference toward the kite conformation both in free and bound calix[4]­pyrrole-based cavitands