Memory of Chirality Approach to the Enantiodivergent Synthesis of Chiral Benzo[<i>d</i>]sultams

The “memory of chirality” stereodivergent synthesis of polyfluorobenzo[<i>d</i>]sultams has been developed. The interest of this protocol resides in the possibility of using the chirality of a starting sulfonamide single enantiomer to synthesize the target sultams in both absolute configurations, by using different base systems, under homogeneous conditions

Memory of Chirality Approach to the Enantiodivergent Synthesis of Chiral Benzo[<i>d</i>]sultams

The “memory of chirality” stereodivergent synthesis of polyfluorobenzo[<i>d</i>]sultams has been developed. The interest of this protocol resides in the possibility of using the chirality of a starting sulfonamide single enantiomer to synthesize the target sultams in both absolute configurations, by using different base systems, under homogeneous conditions

Memory of Chirality Approach to the Enantiodivergent Synthesis of Chiral Benzo[<i>d</i>]sultams

The “memory of chirality” stereodivergent synthesis of polyfluorobenzo[<i>d</i>]sultams has been developed. The interest of this protocol resides in the possibility of using the chirality of a starting sulfonamide single enantiomer to synthesize the target sultams in both absolute configurations, by using different base systems, under homogeneous conditions

Memory of Chirality Approach to the Enantiodivergent Synthesis of Chiral Benzo[<i>d</i>]sultams

The “memory of chirality” stereodivergent synthesis of polyfluorobenzo[<i>d</i>]sultams has been developed. The interest of this protocol resides in the possibility of using the chirality of a starting sulfonamide single enantiomer to synthesize the target sultams in both absolute configurations, by using different base systems, under homogeneous conditions

Solution and Solid State Synthesis of the Discrete Polyiodide I₇^3– under Modular Cation Templation

Discrete I₇³¯ polyiodide is obtained in pure form through solution and solid-state processes thanks to templation by a triammonium cation which elicits the selective formation of the size matching supramolecular anion

Dynamic Characterization of Crystalline Supramolecular Rotors Assembled through Halogen Bonding

A modular molecular kit for the preparation of crystalline molecular rotors was devised from a set of stators and rotators to gain simple access to a large number of structures with different dynamic performance and physical properties. In this work, we have accomplished this with crystalline molecular rotors self-assembled by halogen bonding of diaza­bicyclo­[2.2.2]­octane, acting as a rotator, and a set of five fluorine-substituted iodo­benzenes that take the role of the stator. Using variable-temperature ¹H <i>T</i>₁ spin–lattice relaxation measurements, we have shown that all structures display ultrafast Brownian rotation with activation energies of 2.4–4.9 kcal/mol and pre-exponential factors of the order of (1–9) × 10¹² s^–1. Line shape analysis of quadrupolar echo ²H NMR measurements in selected examples indicated rotational trajectories consistent with the 3-fold or 6-fold symmetric potential of the rotator

Halogen Bonding and Pharmaceutical Cocrystals: The Case of a Widely Used Preservative

3-Iodo-2-propynyl-<i>N</i>-butylcarbamate (IPBC) is an iodinated antimicrobial product used globally as a preservative, fungicide, and algaecide. IPBC is difficult to obtain in pure form as well as to handle in industrial products because it tends to be sticky and clumpy. Here, we describe the preparation of four pharmaceutical cocrystals involving IPBC. The obtained cocrystals have been characterized by X-ray diffraction, solution and solid-state NMR, IR, and DSC analyses. In all the described cases the halogen bond (XB) is the key interaction responsible for the self-assembly of the pharmaceutical cocrystals thanks to the involvement of the 1-iodoalkyne moiety of IPBC, which functions as a very reliable XB-donor, with both neutral and anionic XB-acceptors. Most of the obtained cocrystals have improved properties with respect to the source API, in terms, e.g., of thermal stability. The cocrystal involving the GRAS excipient CaCl₂ has superior powder flow characteristics compared to the pure IPBC, representing a promising solution to the handling issues related to the manufacturing of products containing IPBC

Interplay between Structural and Dielectric Features of New Low k Hybrid Organic–Organometallic Supramolecular Ribbons

The synthesis and characterization of low k one-dimensional (1D) hybrid organic–organometallic supramolecular ribbons <b>3a</b>,<b>b</b>, through halogen-bond driven co-crystallization of <i>trans</i>-[Pt­(PCy₃)₂(CC-4-py)₂] (<b>1</b>) with 1,4-diiodotetrafluorobenzene (<b>2a</b>) and <i>trans</i>-1,2-bis-(2,3,5,6-tetrafluoro-4-iodophenyl)-ethylene (<b>2b</b>), are reported. The co-crystals <b>3a</b>,<b>b</b> have been obtained by isothermal evaporation of a chloroform solution containing the corresponding starting materials at room temperature. X-ray structure determinations show that noncovalent interactions other than halogen bonds help in the construction of the crystal packing; these interactions are stronger in <b>3b</b>, thus reducing the chain mobility with respect to <b>3a</b>. Accordingly, the broadband dielectric spectroscopic determinations, carried out from 10^–2 to 10⁷ Hz and at a temperature ranging from 25 to 155 °C, showed that both <b>3a</b> and <b>3b</b> materials exhibit a real component of dielectric permittivity (ε′) significantly lower than SiO₂. In particular in the case of <b>3b</b>, the rigidity of the 1D chain explains the observed ε″ and tan δ values. A permittivity value that is significantly lower than that of the silica reference, tan δ values lower than 0.02 in the entire investigated temperature range, and less than 0.004 at <i>T</i> < 100 °C make <b>3b</b> a very promising low k hybrid organic–organometallic material for application as dielectric films in next generation microelectronics