Synthesis, Rotational Dynamics, and Photophysical Characterization of a Crystalline Linearly Conjugated Phenyleneethynylene Molecular Dirotor

We report the synthesis, crystal structure, solid-state dynamics, and photophysical properties of 6,13-bis­((4-(3-(3-methoxyphenyl)-3,3-diphenylprop-1-yn-1-yl)­phenyl)­ethynyl)-5,7,12,14-tetrahydro-5,14:7,12-bis­([1,2]­benzeno)­pentacene (<b>1</b>), a molecular dirotor with a 1,4-bis­((4-ethynylphenyl)­ethynyl)­benzene (BEPEB) chromophore. The incorporation of a pentiptycene into the molecular dirotor provides a central stator and a fixed phenylene ring relative to which the two flanking ethynylphenylene rotators can explore various torsion angles; this allows the BEPEB fluorophore dynamics to persist in the solid state. X-ray diffraction studies have shown that molecular dirotor <b>1</b> is packed so that all the BEPEB fluorophores adopt a parallel alignment, this is ideal for the development of functional materials. Variable temperature, quadrupolar echo ²H NMR studies have shown that phenylene rotator flipping has an activation energy of 9.0 kcal/mol and a room temperature flipping frequency of ∼2.6 MHz. Lastly, with measurements in solution, glasses, and crystals, we obtained evidence that the fluorescence excitation and emission spectra of the phenyleneethynylene chromophores is dependent on the extent of conjugation between the phenylene rings, as determined by their relative dihedral angles. This work provides a promising starting point for the development of molecular dirotors with polar groups whose amphidynamic nature will allow for the rapid shifting of solid-state absorption, fluorescence, and birefringence, in response to external electric fields

Synthesis, Rotational Dynamics, and Photophysical Characterization of a Crystalline Linearly Conjugated Phenyleneethynylene Molecular Dirotor

We report the synthesis, crystal structure, solid-state dynamics, and photophysical properties of 6,13-bis­((4-(3-(3-methoxyphenyl)-3,3-diphenylprop-1-yn-1-yl)­phenyl)­ethynyl)-5,7,12,14-tetrahydro-5,14:7,12-bis­([1,2]­benzeno)­pentacene (<b>1</b>), a molecular dirotor with a 1,4-bis­((4-ethynylphenyl)­ethynyl)­benzene (BEPEB) chromophore. The incorporation of a pentiptycene into the molecular dirotor provides a central stator and a fixed phenylene ring relative to which the two flanking ethynylphenylene rotators can explore various torsion angles; this allows the BEPEB fluorophore dynamics to persist in the solid state. X-ray diffraction studies have shown that molecular dirotor <b>1</b> is packed so that all the BEPEB fluorophores adopt a parallel alignment, this is ideal for the development of functional materials. Variable temperature, quadrupolar echo ²H NMR studies have shown that phenylene rotator flipping has an activation energy of 9.0 kcal/mol and a room temperature flipping frequency of ∼2.6 MHz. Lastly, with measurements in solution, glasses, and crystals, we obtained evidence that the fluorescence excitation and emission spectra of the phenyleneethynylene chromophores is dependent on the extent of conjugation between the phenylene rings, as determined by their relative dihedral angles. This work provides a promising starting point for the development of molecular dirotors with polar groups whose amphidynamic nature will allow for the rapid shifting of solid-state absorption, fluorescence, and birefringence, in response to external electric fields

Distribution of HIV-1 subtypes in the studied population.

<p>Distribution of HIV-1 subtypes in the studied population.</p

Phylogenetic analysis of HIV <i>gag</i> gene (p24-p7) sequences (nt 1577–2040, HXB2) from HIV infected Nairobi residents.

<p>This tree (neighbor-joining) was created by aligning the selected sequences with reference sequences from Los Alamos database shown in bold). The sequence F1.FR.96.MP411 was selected as the out group.</p

Distribution of study subjects on the basis of gender, age, occupation, ethnicity and risk factors.

<p>Distribution of study subjects on the basis of gender, age, occupation, ethnicity and risk factors.</p

Neighbor-Joining Phylogenetic trees of the three most represented subtypes, A (Fig. 2A), D (Fig. 2B) and C (Fig. 2C), depicting geographical associations of the studied sample group with other global regions.

<p>Reference Sequences from Los Alamaos Database have been indicated in bold. Out groups selected for Fig. 2A, B, and C were, respectively, A.EE.02.EST2002 394, NL.x.M12020, and IL.98.98IS002.</p

Additional file 1 of Expressional variations of Kaiso: an association with pathological characteristics and field cancerization of OSCC

Additional file 1

Crystal Fluidity Reflected by Fast Rotational Motion at the Core, Branches, and Peripheral Aromatic Groups of a Dendrimeric Molecular Rotor

Low packing densities are key structural features of amphidynamic crystals built with static and mobile components. Here we report a loosely packed crystal of dendrimeric rotor <b>2</b> and the fast dynamics of all its aromatic groups, both resulting from the hyperbranched structure of the molecule. Compound <b>2</b> was synthesized with a convergent strategy to construct a central phenylene core with stators consisting of two layers of triarylmethyl groups. Single crystal X-ray diffraction analysis confirmed a low-density packing structure consisting of one molecule of <b>2</b> and approximately eight solvent molecules per unit cell. Three isotopologues of <b>2</b> were synthesized to study the motion of each segment of the molecule in the solid state using variable temperature quadrupolar echo ²H NMR spectroscopy. Line shape analysis of the spectra reveals that the central phenylene, the six branch phenylenes, and the 18 periphery phenyls all display megahertz rotational dynamics in the crystals at ambient temperature. Arrhenius analysis of the data gives similar activation energies and pre-exponential factors for different parts of the structure. The observed pre-exponential factors are 4–6 orders of magnitude greater than those of elementary site-exchange processes, indicating that the dynamics are not dictated by static energetic potentials. Instead, the activation energies for rotations in the crystals of <b>2</b> are controlled by temperature dependent local structural fluctuations and crystal fluidity

Crystal Fluidity Reflected by Fast Rotational Motion at the Core, Branches, and Peripheral Aromatic Groups of a Dendrimeric Molecular Rotor

Low packing densities are key structural features of amphidynamic crystals built with static and mobile components. Here we report a loosely packed crystal of dendrimeric rotor <b>2</b> and the fast dynamics of all its aromatic groups, both resulting from the hyperbranched structure of the molecule. Compound <b>2</b> was synthesized with a convergent strategy to construct a central phenylene core with stators consisting of two layers of triarylmethyl groups. Single crystal X-ray diffraction analysis confirmed a low-density packing structure consisting of one molecule of <b>2</b> and approximately eight solvent molecules per unit cell. Three isotopologues of <b>2</b> were synthesized to study the motion of each segment of the molecule in the solid state using variable temperature quadrupolar echo ²H NMR spectroscopy. Line shape analysis of the spectra reveals that the central phenylene, the six branch phenylenes, and the 18 periphery phenyls all display megahertz rotational dynamics in the crystals at ambient temperature. Arrhenius analysis of the data gives similar activation energies and pre-exponential factors for different parts of the structure. The observed pre-exponential factors are 4–6 orders of magnitude greater than those of elementary site-exchange processes, indicating that the dynamics are not dictated by static energetic potentials. Instead, the activation energies for rotations in the crystals of <b>2</b> are controlled by temperature dependent local structural fluctuations and crystal fluidity

Table_2_A comparative absorption study of sucrosomial® orodispersible vitamin D3 supplementation vs. a reference chewable tablet and soft gel capsule vitamin D3 in improving circulatory 25(OH)D levels in healthy adults with vitamin D deficiency—Results from a prospective randomized clinical trial.pdf

BackgroundVitamin D (Vit D) deficiency (VDD), associated with diverse health conditions, is commonly treated with Vit D3 supplements. However, the gastrointestinal (GI) absorption of Vit D3 in different formulations has not been well studied.ObjectiveWe aimed to compare the absorption of an innovative phospholipids-sucrester matrix biodelivery vehicle-based (sucrosomial®) orodispersible Vit D3 preparation against a reference chewable tablet and soft gel capsule (SGC) Vit D3 formulations in Vit D-deficient healthy adults.MethodsIn study 1, 25 subjects were randomized to receive a weekly single dose of 200,000 IU of sucrosomial® Vit D3 (n = 12) or chewable tablet Vit D3 (n = 13) for 3 weeks. In study 2, 20 subjects were randomized to receive a single dose of 200,000 IU every other week of sucrosomial® Vit D3 (n = 10) or SGC Vit D3 (n = 10) for 6 weeks. Circulatory 25-hydroxyvitamin D3 [25(OH)D] levels were reassessed after 2, 3, and 6 weeks in study 1 and after 4 and 6 weeks in study 2.ResultsIn study 1, after 2 weeks, circulatory 25(OH)D levels increased significantly in both Vit D3 treatment groups (p ® Vit D3 group, with no further considerable change after 3 and 6 weeks in both groups. Overall, at all three follow-ups, sucrosomial® Vit D3 treatment achieved significantly higher and sustained 25(OH)D levels (p ® group with statistically significant differences between the two treatment groups (p = 0.02). At the 6-week follow-up, only subjects in the sucrosomial® Vit D3 group showed a further increase in circulatory 25(OH)D levels (p = 0.049), but no further significant changes in the levels of the SGC Vit D3 group (p = 0.062), showing a statistically significant difference between the two treatment groups (p = 0.002). The Vit D3 treatment was well tolerated by all participants, and no treatment-emergent effects or serious adverse events were reported.ConclusionOur results suggest that the sucrosomial® Vit D3 preparation absorbs efficiently in the GI system, achieving adequately higher and sustained circulatory Vit D levels in VDD, and thus can effectively contribute to the body protection against VDD-associated health conditions.Clinical trial registrationclinicaltrials.gov, identifier: NCT05706259.</p