Marcos Chas

A metal-directed self-assembled electroactive cage with bis(pyrrolo)tetrathiafulvalene (BPTTF) side walls

A straightforward synthesis of a bis(pyrrolo)tetrathiafulvalene (BPTTF)-based tetratopic ligand bearing four pyridyl units is described. The first example of a TTF-based self-assembled cage has been produced from this redox-active ligand through metal-directed synthesis with a cis-coordinated square-planar Pt(II) complex. The resulting cage corresponds to a trigonal-prismatic structure, as shown by X-ray crystallography. A UV-vis titration indicated that the electron-rich cavity can be used to incorporate one molecule of tetrafluorotetracyano-p-quinodimethane (TCNQF(4)).

Selective Pairwise Encapsulation Using Directional Interactions

Trimethylamine N-oxide and trimethylphosphine oxide guests are pairwise encapsulated in a dimeric capsule self-assembled from a tetraurea aryl extended calix[4]pyrrole. The capsule possesses polar functional groups in its interior capable of controlling the orientation of the included guests. A modest selectivity is observed during the encapsulation process that is beyond the controls of size or shape exclusion.

Physical origin of the third order nonlinear optical response of orthogonal pyrrolo-tetrathiafulvalene derivatives

We present the third order nonlinear optical study of tetrathiafulvalene-based molecular corners. Degenerate four-wave mixing measurements have been done to provide information about the magnitude and the origin of the nonlinearity, while the nonlinear absorption has been separately measured by performing “open aperture” Z-scan measurements. The response has been found to be strongly dependent upon the structure of the molecular corners.

A BPTTF-based self-assembled electron-donating triangle capable of C60 binding

A kinetically stable self-assembled redox-active triangle is isolated. The resulting electron-donating cavity, which incorporates three BPTTF units, exhibits a remarkable binding ability for electron-deficient C(60), supported by a favorable combination of structural and electronic features.

A self-assembled bis(pyrrolo)tetrathiafulvalene-based redox active square

The synthesis and full characterization of a redox-active π-donating molecular square is described, through coordination-driven self-assembly of a new key bis(pyrrolo)TTF building block with Pt(II) salts; the electrochemical behaviour of the square is consistent with noninteracting bis(pyrrolo)TTF units.

Chemo- and enantioselective sulfoxidation of bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) into chiral BEDT-TTF-sulfoxide

Selective sulfoxidation of BEDT-TTF (bis(ethylenedithio)-tetrathiafulvalene) with enantiopure (camphoryl-sulfonyl)oxaziridine derivatives provided the inner monosulfoxide, as demonstrated using single crystal X-ray analysis, with an enantiomeric excess of 44% (up to 74% after recrystallization).

Efficient self-sorting of a racemic tetra-urea calix[4]pyrrole into a single heterodimeric capsule.

A racemic calix[4]pyrrole self-sorts into a single achiral heterodimeric capsule. This process is induced either by encapsulation of one ditopic or two monotopic N-oxide guests. The influence of the guest structure in the dynamics of the disproportionation process of the two homochiral capsules is reported. The unidirectional sense of rotation of the urea groups assigned to the heterodimeric capsule is explained as the outcome of an induction of chirality from the stereogenic centers.

N-Aryl Pyrrolo-tetrathiafulvalene Based Ligands: Synthesis and Metal Coordination

A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, reminiscent of the corresponding MPTTF derivatives, are provided. When the aryl group is a binding pyridyl unit, the MPTTF derivative 10a can coordinate M(II) salts (M = Pt, Pd). The first examples of metal-directed orthogonal MPTTF-based dimers 11-14, obtained through coordination of 10a to cis-blocked square planar Pt or Pd complexes are described. Studies on the parameters influencing the dimer construction are presented, as well as first recognition properties of the resulting electron-rich clip for C(60).

A dissymmetric molecular capsule with polar interior and two mechanically locked hemispheres

The synthesis and chiral resolution of a dissymmetric tetraurea-calix[4]pyrrole/tetraurea-calix[4]arene molecular capsule with two hemispheres mechanically locked is described. The assembly features a bis-[2]catenated topology and shows reversible molecular co-encapsulation of two different neutral molecules or two oppositely charged ions.

Exclusive Self-Assembly of a Polar Dimeric Capsule between Tetraurea Calix[4]pyrrole and Tetraurea Calix[4]arene

The exclusive self-sorting observed in the self-assembly process between tetraurea benzyl calix[4]pyrroles and tetraurea tolyl calix[4]arene to afford unprecedented hybrid dimeric capsules with polar interiors is described. The coencapsulation of a solvent molecule with an organic guest yields four particle aggregates in which the guests are confined and restricted into single hemispheres due to the polar requirements of the internal cavity.