5 research outputs found
Cooperative 1D Triazole-Based Spin Crossover Fe<sup>II</sup> Material With Exceptional Mechanical Resilience
Cooperative 1D Triazole-Based Spin Crossover Fe<sup>II</sup> Material With Exceptional Mechanical Resilienc
Ligandless Palladium-Catalyzed Regioselective Direct CāH Arylation of Imidazo[1,2ā<i>a</i>]imidazole Derivatives
Herein a novel access to functionalizable
6-substituted imidazoĀ[1,2-<i>a</i>]Āimidazole scaffolds is
described. The reactivity of this
heterobicyclic unit toward direct CāH arylation was studied,
and conditions allowing regioselective arylation at position 3 were
successfully developed. The practicability of this method is manifested
by the ligandless conditions and low catalyst loading. The strategy
is functional group tolerant and provides rapid access to a large
variety of 3,6-diĀ(hetero)Āarylated imidazoĀ[1,2-<i>a</i>]Āimidazole
derivatives. A second arylation at position 2 was then carried out,
and a library of diversified 2,3,6-triĀ(hetero)Āarylated imidazoĀ[1,2-<i>a</i>]Āimidazoles was generated in good yields. A one-pot, two-step
procedure was finally developed
Optimized Local Synthetic Conditions Induce Size Reduction and Phase Purification in {[Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>)}<sub><i>n</i></sub> Spin Crossover Particles
The well-known synthesis of the two polymorphs of the
{[Fe(Htrz)2(trz)](BF4)}n spin
crossover coordination polymer is explored with new template-free
methods that allow a control over the local synthetic conditions.
A āone-potā synthesis approach is developed, in which
the solid reactants are mixed together before the addition of the
solvent, which is expected to generate instantaneous supersaturation
conditions favoring the nucleation of particles over their growth.
In a second method, the addition of ultrasound pulses promotes the
appearance of local āhot spotsā that affect the local
temperature and allow exploring a different region of the concentrationātemperature
phase diagram, leading to an increase in the phase purity of the product.
These two syntheses are compared to the classical method in which
the reactants are first dissolved in separate solutions before being
mixed. The use of a one-pot synthesis, with or without ultrasound
pulses, induces a downsizing of the particle size by a factor of 500
on their volume. The addition of ultrasound pulses allows moving from
a mixture of polymorphs I and II of this
compound to the pure phase I. These approaches open the
way to more studies on the control over the size or phase purity in
such molecular compounds, without the use of any surfactant
Ligandless Palladium-Catalyzed Regioselective Direct CāH Arylation of Imidazo[1,2ā<i>a</i>]imidazole Derivatives
Herein a novel access to functionalizable
6-substituted imidazoĀ[1,2-<i>a</i>]Āimidazole scaffolds is
described. The reactivity of this
heterobicyclic unit toward direct CāH arylation was studied,
and conditions allowing regioselective arylation at position 3 were
successfully developed. The practicability of this method is manifested
by the ligandless conditions and low catalyst loading. The strategy
is functional group tolerant and provides rapid access to a large
variety of 3,6-diĀ(hetero)Āarylated imidazoĀ[1,2-<i>a</i>]Āimidazole
derivatives. A second arylation at position 2 was then carried out,
and a library of diversified 2,3,6-triĀ(hetero)Āarylated imidazoĀ[1,2-<i>a</i>]Āimidazoles was generated in good yields. A one-pot, two-step
procedure was finally developed
NaproxenāNicotinamide Cocrystals: Racemic and Conglomerate Structures Generated by CO<sub>2</sub> Antisolvent Crystallization
Cocrystallization of naproxen racemic
mixture and nicotinamide
was investigated in this work, using compressed CO<sub>2</sub> as
antisolvent. A novel racemic cocrystal structure containing both enantiomers
of naproxen linked to nicotinamide has been produced thanks to the
CO<sub>2</sub> antisolvent batch crystallization process. The structure
of the molecular complex and its intermolecular interactions were
investigated by single-crystal X-ray diffraction and attenuated total
reflectance Fourier transform infrared spectroscopy. The antisolvent
feed rate was found to have a direct influence on the cocrystallization
outcome. The racemic cocrystal was obtained at slow and moderate CO<sub>2</sub> feed rate, while very fast introduction of CO<sub>2</sub> resulted in the formation of a mixture of chiral cocrystals (conglomerate).
Cross-seedings, thermal analysis, and temperature-resolved X-ray powder
diffraction were used to probe the relationship between the different
phases. In addition, all powders produced with CO<sub>2</sub> technology
were obtained as cocrystal-pure, without significant excess of naproxen
or nicotinamide homocrystals