An Alternate [2×2] Grid Constructed Around TiO4 N2 Units.

The formation of a tetranuclear self-assembled species constructed around a TiO4 N2 motif is reported. This aggregate is generated from Ti(Oi Pr)4 , 2,2'-bipyrimidine (bpym) and a bis-biphenol strand (L2 H4 ) where two 2,2'-biphenol units are connected with a biphenyl spacer. The solid-state structure of the [Ti4 (L2 )4 (bpym)4 ] architecture reveals the formation of an unprecedented chiral alternate [2×2] grid. In addition to the structural characterization of the [Ti4 (L2 )4 (bpym)4 ] architecture, geometry optimisation on various possible isomeric tetrameric assemblies ([2×2] grid, alternate [2×2] grid, circular helicate or cyclic hemihelicate) is performed using DFT calculations. These results confirm the higher stability of the alternate [2×2] grid over the other possible tetranuclear isomers and allow examining the replacement of the bpym ligands by two novel diimine chelates within the tetranuclear assembly (2,2'-bipyridine=bipy and 2,2'-bipyrazine=bipyraz). From this initial theoretical investigation, the competition between these three nitrogen ligands in the course of the self-assembly process is next evaluated. Overall, this investigation shows that the exclusive formation of the alternate [2×2] grid is driven by CH⋅⋅⋅N interactions.

Metabolic Shifts as the Hallmark of Most Common Diseases: The Quest for the Underlying Unity.

A hyper-specialization characterizes modern medicine with the consequence of classifying the various diseases of the body into unrelated categories. Such a broad diversification of medicine goes in the opposite direction of physics, which eagerly looks for unification. We argue that unification should also apply to medicine. In accordance with the second principle of thermodynamics, the cell must release its entropy either in the form of heat (catabolism) or biomass (anabolism). There is a decreased flow of entropy outside the body due to an age-related reduction in mitochondrial entropy yield resulting in increased release of entropy in the form of biomass. This shift toward anabolism has been known in oncology as Warburg-effect. The shift toward anabolism has been reported in most diseases. This quest for a single framework is reinforced by the fact that inflammation (also called the immune response) is involved in nearly every disease. This strongly suggests that despite their apparent disparity, there is an underlying unity in the diseases. This also offers guidelines for the repurposing of old drugs.

Verification of Nuclear Magnetic Resonance Characterization of Traditional Homeopathically Manufactured Metal (Cuprum metallicum) and Plant (Gelsemium sempervirens) Medicines and Controls.

BACKGROUND: Nuclear magnetic resonance (NMR) proton relaxation is sensitive to the dynamics of the water molecule, H2O, through the interaction of the spin of the proton (1H) with external magnetic and electromagnetic fields. NMR relaxation times describe how quickly the spin of 1H, forced in a direction by an external electromagnetic field, returns to a normal resting position. As a result, such measurements allow us potentially to describe higher structuring of water in homeopathic medicines. OBJECTIVE: The purpose of the present study was to verify whether specific NMR relaxation times could be measured in full lines of cH dynamizations of a metal (copper) and of a plant substance (Gelsemium sempervirens), compared with a solvent control, a potentized lactose control and a control prepared by simple dilution, in three production lines. It is aimed at verification of a previous publication (2017) on two new manufacturing lines of the same starting material and controls. MATERIALS AND METHODS: To monitor dilution and potentization processes, measurements of 1H spin-lattice T1 and spin-spin T2 relaxation times were used. T1 and T2 relaxation times were measured at 25°C with a spin analyser working at a frequency of 20 MHz. To account for its possible role as a confounding factor, free oxygen was also measured in all samples, using a MicroOptode meter. RESULTS: When the values of the three production lines were pooled, a statistically significant discrimination of NMR relaxation times between the medicines and their controls was confirmed. We found for copper cH and Gelsemium sempervirens cH a highly significant influence of the starting material (p = 0.008), a highly significant influence of level of dilution (p < 0.001), and a significant influence of the O2 concentration (p = 0.04). CONCLUSIONS: We have evidence of an obvious retention of a specific magnetic resonance signal when a substance (lactose, copper, Gelsemium) is diluted/potentized in pure water. This means that homeopathic solutions cannot be considered to be pure water. O2 is a covariant and not an explanatory variable: this factor itself is too weak to explain the NMR signal specificities in potentized samples. Homeopathic dilutions may thus have a specific material configuration governed not only by the potentized substance but also by the chemical nature of the containers, the chemical nature of dissolved gases and even by the electromagnetic environment. This sensitivity of homeopathically prepared medicines to electromagnetic fields may be amplified by the processes routinely applied during their preparation; because it occurs only when a dynamization has been performed, we may call this phenomenon "dynamic pharmacy".

Bent 1,10-Phenanthroline Ligands within Octahedral Complexes Constructed around a TiO4N2 Core.

The synthesis of monomeric octahedral complexes constructed around a TiO4N2 core bearing neocuproine derivatives is detailed. These architectures follow the [Ti(1)2(N-N)] general formulas, where 1 is the 6,6'-diphenyl-2,2'-biphenolato ligand and N-N is a 1,10-phenanthroline derivative. Single-crystal analysis revealed that the neocuproine-based ligands within these architectures adopt a nonplanar geometry. The distortion of these aromatic diimine systems has been quantified through measurement of a torsion angle (α) and a dihedral angle (ß) defined by two planes within the aromatic diimine molecule (π1 and π2), permitting one to evaluate the twisting and bending of a coordinated nitrogen ligand, respectively. Next, the scope of this investigation was extended to the synthesis of a dimeric architecture, [Ti2(1)4(3)], where 3 is the 5,5'-bis(neocuproine) ligand. Again, a strong distortion of the neocuproine fragments was characterized in the crystalline state for such a complex. The UV-visible properties of these complexes were interpreted with the help of time-dependent density functional theory calculations. The solution behavior as well as good hydrolytic stability of these species has been established.

Dipyrrolyldiketonato Titanium(IV) Complexes from Monomeric to Multinuclear Architectures: Synthesis, Stability, and Liquid-Crystal Properties.

Dipyrrolyldiketone ligands (dpkH) are used with Ti(OiPr)4 to afford monomeric titanium(IV) complexes displaying the general formula C2-[Ti(dpk)2(OiPr)2]. The dpkH ligands employed consist of two dipyrrolyldiketone compounds (2H and 3H) and three diphenyl-substituted analogues (4H-6H). The behavior of these octahedral [Ti(dpk)2(OiPr)2] species in solution was investigated by 1H NMR at variable temperatures. Dynamic phenomena were evidenced, and the activation parameters associated with these processes (ΔH⧧, ΔS⧧, and ΔG⧧) were retrieved. [Ti(dpk)2(OiPr)2] complexes are precursors for the formation of high-nuclearity aggregates whose structures depend on the substituents on the diketone backbone. The crystal structures of monomeric ([Ti(1)2(OiPr)2]; 1 is the 1,3-diphenyl-1,3-propanedionato ligand) and [Ti(2)2(OEt)2]), dimeric ([Ti2(1)4(µ2-O)2]), and tetrameric ([Ti4(4)8(µ2-O)4]) species have been established, and the origin of this structural diversity is discussed. The solid-state optical properties of several complexes were determined and interpreted with the help of DFT calculations. Finally, the dinuclear complex [Ti(6)2(µ2-O)2] was synthesized, where ligand 6 incorporates six long alkyl chains (C16H33). This complex shows rich mesomorphic properties, with an original room-temperature plastic crystal phase followed by a hexagonal columnar liquid-crystalline phase.

Label-free proteome of water buffalo (Bubalus bubalis) seminal plasma.

The study aimed to describe the Bubalus bubalis seminal plasma proteome using a label-free shotgun UDMSE approach. A total of 859 nonredundant proteins were identified across five biological replicates with stringent identification. Proteins specifically related to sperm maturation and protection, capacitation, fertilization and metabolic activity were detected in the buffalo seminal fluid. In conclusion, we provide a comprehensive proteomic profile of buffalo seminal plasma, which establishes a foundation for further studies designed to understand regulation of sperm function and discovery of novel biomarkers for fertility. MS data are available in the ProteomeXchange with identifier PXD003728.

Nuclear Magnetic Resonance characterization of traditional homeopathically manufactured copper (Cuprum metallicum) and plant (Gelsemium sempervirens) medicines and controls.

BACKGROUND: NMR proton relaxation is sensitive to the dynamics of the water molecule H2O, through the interaction of the spin of the proton (1H) with external magnetic and electromagnetic fields. METHODS: We measured dilution and potentization processes through measurements of 1H spin-lattice T1 and spin-spin T2 relaxation times. In order to interpret the recorded fluctuations in T1- or T2-values, experimental data were linearized by investigating how the area under a fluctuating time = f(dilution) curve (dilution integral or DI) changes with dilution. Two kinds of fitting procedures were considered: chi-square fitting with a goodness-of-fit probability, and least absolute deviations criterion with Pearson's linear correlation coefficient. RESULTS: We showed that fluctuations are not attributable to random noise and/or experimental errors, evidencing a memory effect quantifiable by the slope of the DI = f(dilution) straight line. For all experiments, correlation coefficients were found to lie above 0.9999, against 0.999 for random noise. The discrimination between experimental slopes and slopes associated with random noise data was very good at a five-sigma level of confidence (i.e. probability 3 × 10-7). Discrimination between experimental slopes at a five-sigma level was possible in most cases, with three exceptions: gelsemium aqua pura v gelsemium dilution (four-sigma); copper aqua pura v gelsemium aqua pura (four-sigma) and copper simple dilution v gelsemium simple dilution (three-sigma). All potentized samples show very good discrimination (at least nine-sigma level) against aqua pura, lactose or simple dilution. It was possible to transform the associated relaxation times into a molecular rotational correlation time τc and an average spin-spin distance d. Our experiments thus point to a considerable slowing down of molecular movements (τc > 1300 ps or T = 224-225 K) around water molecules up to a distance of 3.7 Å, values. It was also possible to rule out other possible mechanisms of relaxation (diffusive motion, 17O-1H relaxation or coupling with the electronic spin, S = 1, of dissolved dioxygen molecules). CONCLUSION: There is clear evidence that homeopathic solutions cannot be considered as pure water as commonly assumed. Instead, we have evidenced a clear memory effect upon dilution/potentization of a substance (water, lactose, copper, gelsemium) reflected by different rotational correlation times and average H⋯H distances. A possible explanation for such a memory effect may lie in the formation of mesoscopic water structures around nanoparticles and/or nanobubbles mediated by zero-point fluctuations of the vacuum electromagnetic field as suggested by quantum field theories. The existence of an Avogadro's 'wall' for homeopathically-prepared medicines is not supported by our data. Rather it appears that all dilutions have a specific material configuration determined by the potentized substance, also by the chemical nature of the containers, and dissolved gases and the electromagnetic environment. This sensitivity of homeopathically-prepared medicines to electromagnetic fields may be amplified by the highly non-linear processing routinely applied in the preparation of homeopathic medicines. Future work is needed in such directions. The time is now ripe for a demystification of the preparation of homeopathic remedies.

A bowl-shaped circular trinuclear helicate generated from a TiO4 N2 motif by a multicomponent self-assembly approach.

The synthesis of a bowl-shaped trinuclear circular titanium-based helicate is reported. The strategy allowing access to this neutral architecture is based on a multicomponent self-assembly approach in which the ligands involved in the process are a bis-biphenol strand and 2,2'- bipyrimidine. By reacting the bis-biphenol ligand and 2,2'-bipyrimidine with an equimolar amount [Ti(OiPr)4 ], a bowl-shaped architecture is obtained through the formation of 18 new coordination bonds. This aggregate built from three octahedral TiO4 N2 nodes displays an unusually high stability in solution compared to related species. In addition, by modifying the stoichiometry of the initial components, two assemblies incorporating two titanium centers bridged by a 2,2'-bipyrimidine ligand are obtained. The crystal structures of these species are reported.

Magnetic resonance imaging of hypertrophic cardiomyopathy: beyond left ventricular wall thickness.

During the past decade, cardiac magnetic resonance has gained increasing popularity in the diagnosis of hypertrophic cardiomyopathy because of its greater accuracy and better characterization of cardiac morphology compared with other imaging modalities. In this pictorial essay, a global clinical portrait of hypertrophic cardiomyopathy will be drawn. The various radiologic findings associated with each variant of hypertrophic cardiomyopathy, and the clinical edge offered by cardiac magnetic resonance will be discussed.

A remarkable solvent effect on the nuclearity of neutral titanium(IV)-based helicate assemblies.

The spontaneous self-assembly of a neutral circular trinuclear Ti(IV) -based helicate is described through the reaction of titanium(IV) isopropoxide with a rationally designed tetraphenolic ligand. The trimeric ring helicate was obtained after diffusion of n-pentane into a solution with dichloromethane. The circular helicate has been characterized by using single-crystal X-ray diffraction study, (13) C CP-MAS NMR and (1) H NMR DOSY solution spectroscopic, and positive electrospray ionization mass-spectrometric analysis. These analytical data were compared with those obtained from a previously reported double-stranded helicate that crystallizes in toluene. The trimeric ring was unstable in a pure solution with dichloromethane and transformed into the double-stranded helicate. Thermodynamic analysis by means of the PACHA software revealed that formation of the double-stranded helicates was characterized by ΔH(toluene)=-30 kJ mol(-1) and ΔS(toluene)=+357 J K(-1) mol(-1) , whereas these values were ΔH(CH2 Cl2 )=-75 kJ mol(-1) and ΔS(CH2 Cl2 )=-37 J K(-1) mol(-1) for the ring helicate. The transformation of the ring helicate into the double-stranded helicate was a strongly endothermic process characterized by ΔH(CH2 Cl2 )=+127 kJ mol(-1) and ΔH(n-pentane)=+644 kJ mol(-1) associated with a large positive entropy change ΔS=+1115 J K(-1) ⋅mol(-1) . Consequently, the instability of the ring helicate in pure dichloromethane was attributed to the rather high dielectric constant and dipole moment of dichloromethane relative to n-pentane. Suggestions for increasing the stability of the ring helicate are given.

[Risks associated with unrestricted consumption of alkaline-reduced water]. / Les risques d'une libre consommation d'eau réductrice alcaline produite par électrolyse.

Consumption of alkaline reduced water produced by domestic electrolysis devices was approved in Japan in 1965 by the Minister of Health, Work and Wellbeing, for the treatment of gastrointestinal disorders. Today, these devices are also freely available in France. The commercial information provided with the devices recommends the consumption of 1 to 1.5 liters per day, not only for gastrointestinal disorders but also for numerous other illnesses such as diabetes, cancer and inflammation. Academic research on this subject has been undergoing in Japan since 1990, and has established that the active ingredient is dissolved dihydrogen, which eliminates the free radical HO· in vivo. It has also been shown that electrode degradation during use of the devices releases highly reactive platinum nanoparticles, the toxicity of which is unknown. The authors of this report recommend alerting the French health authorities to the uncontrolled availability of these devices that generate drug substances and should therefore be subject to regulatory requirements.

Metabolic Shift and Hyperosmolarity Underlie Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is both a poorly understood and devastating disease. Here, we analyze the physico-chemical forces at stake, including osmolarity, redox shift, and pressure due to inflammation. Hyperosmolarity plays a key role in diseases of the anterior segment of the eye such as glaucoma, cataracts or dry eyes, and corneal ulceration. However, its role in macular degeneration has been largely overlooked. Hyperosmolarity is responsible for metabolic shifts such as aerobic glycolysis which increases lactate secretion by Muller cells. Increased osmolarity will also cause neoangiogenesis and cell death. Because of its unique energetic demands, the macula is very sensitive to metabolic shifts. As a proof of concept, subretinal injection of drugs increasing hyperosmolarity such as polyethylene glycol causes neoangiogenesis and drusen-like structures in rodents. The link between AMD and hyperosmolarity is reinforced by the fact that treatments aiming to restore mitochondrial activity, such as lipoic acid and/or methylene blue, have been experimentally shown to be effective. We suggest that metabolic shift, inflammation, and hyperosmolarity are hallmarks in the pathogenesis and treatment of AMD.

Complication rates are not higher after outpatient compared to inpatient fast-track total hip arthroplasty: a propensity-matched prospective comparative study.

PURPOSE: Concerns remain with regards to safety of fast-track (FT) and especially outpatient procedures. The purpose of this study was to compare complication rates and clinical outcomes of propensity-matched patients who received FT total hip arthroplasty (THA) in outpatient versus inpatient settings. The hypothesis was that 90-day postoperative complication rates of outpatient FT THA would not be higher than after inpatient FT THA. METHODS: This is a prospective study of consecutive patients who received FT THA at various rates of outpatient and inpatient surgery by 10 senior surgeons (10 centres). The decision between outpatient and inpatient surgery was made on a case-by-case basis depending on the surgeon and patient. All patients were followed until 90 days after surgery. Complications, readmissions and reoperations were collected, and their severity was assessed according to Clavien-Dindo. Patients completed Oxford Hip Score (OHS) at the latest follow-up. RESULTS: Compared to inpatient FT THA, patients scheduled for outpatient FT THA had no significant differences in 90-day postoperative complication rates (10.7% vs. 12.9%, p = 0.129). There were no significant differences between the 2 groups in 90-day readmission rates and reoperation rates, in severity of postoperative complications, and in time of occurrence of postoperative complications. CONCLUSIONS: There were no differences in rates of intraoperative complications, 90-day postoperative complications, readmissions, or reoperations between outpatient and inpatient FT THA. These findings may help hesitant surgeons to move towards outpatient THA pathways as there is no greater risk of early postoperative complications that could be more difficult to manage after discharge.

In vivo collection of follicular fluid and granulosa cells from individual follicles of different diameters in cattle by an adapted ovum pick-up system.

BACKGROUND: Most studies on granulosa cell (GC) function in cattle have been performed using GC and follicular fluid (FF) samples collected from slaughterhouse ovaries. Using this approach, the follicular developmental stage and functional status are unknown and indirectly inferred, limiting data interpretation. Ultrasound-guided follicle aspiration has previously been used to recover GC or FF samples, but this was mostly carried out in large follicles or pools of small follicles, without recording the efficiency of recovery. The present study was aimed at adapting and evaluating an ovum pick-up (OPU) system for the in vivo recovery of FF and GC from individual follicles of different diameters. METHODS: In the first trial, the losses of fluid inside the tubing system were calculated using a conventional or an adapted-OPU system. Blood plasma volumes equivalent to the amount of FF in follicles of different diameters were aspirated using a conventional OPU Teflon circuit. The OPU system was then adapted by connecting 0.25 mL straws to the circuit. A second trial evaluated the efficiency of FF recovery in vivo. Follicles ranging from 4.0 to 16.8 mm in diameter were aspirated individually using the conventional or adapted-OPU systems. A third trial assessed the in vivo recovery of GC and the subsequent amount of RNA obtained from the follicles of different diameters from Holstein and Gir cattle. RESULTS: In Trial I, the plasma recovery efficiency was similar (P > 0.05) for the volumes expected for 12 and 10 mm follicles, but decreased (P < 0.05) for smaller follicles (45.7+/-4.0%, 12.4+/-4.3% and 0.0+/-0.0% for 8, 6, and 4 mm follicles, respectively). Using the adaptation, the losses intrinsic to the aspiration system were similar for all follicle diameters. In Trial II, the expected and recovered volumes of FF were correlated (r = 0.89) and the efficiency of recovery was similar among follicles <12 mm, while larger follicles had a progressive increase in FF losses that was not related to the tubing system. In Trial III, the number of GC and amount of RNA obtained were not affected (P > 0.05) by follicle size, but differed according to breed (615,054+/-58,122 vs 458,095+/-36,407 for Holstein and Gir, respectively; P < 0.05). CONCLUSIONS: The adapted-OPU system can be successfully used for the in vivo collection of FF and GC from follicles of different diameters. This will enable further endocrine, cellular, and gene expression analyses.

Genomic medicine in Africa: a need for molecular genetics and pharmacogenomics experts.

The large-scale implementation of genomic medicine in Africa has not been actualized. This overview describes how routine molecular genetics and advanced protein engineering/structural biotechnology could accelerate the implementation of genomic medicine. By using data-mining and analysis approaches, we analyzed relevant information obtained from public genomic databases on pharmacogenomics biomarkers and reviewed published studies to discuss the ideas. The results showed that only 68 very important pharmacogenes currently exist, while 867 drug label annotations, 201 curated functional pathways, and 746 annotated drugs have been catalogued on the largest pharmacogenomics database (PharmGKB). Only about 5009 variants of the reported ∼25,000 have been clinically annotated. Predominantly, the genetic variants were derived from 43 genes that contribute to 2318 clinically relevant variations in 57 diseases. Majority (∼60%) of the clinically relevant genetic variations in the pharmacogenes are missense variants (1390). The enrichment analysis showed that 15 pharmacogenes are connected biologically and are involved in the metabolism of cardiovascular and cancer drugs. The review of studies showed that cardiovascular diseases are the most frequent non-communicable diseases responsible for approximately 13% of all deaths in Africa. Also, warfarin pharmacogenomics is the most studied drug on the continent, while CYP2D6, CYP2C9, DPD, and TPMT are the most investigated pharmacogenes with allele activities indicated in African and considered to be intermediate metaboliser for DPD and TPMT (8.4% and 11%). In summary, we highlighted a framework for implementing genomic medicine starting from the available resources on ground.

Toxicity of the spike protein of COVID-19 is a redox shift phenomenon: A novel therapeutic approach.

We previously demonstrated that most diseases display a form of anabolism due to mitochondrial impairment: in cancer, a daughter cell is formed; in Alzheimer's disease, amyloid plaques; in inflammation cytokines and lymphokines. The infection by Covid-19 follows a similar pattern. Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction. This unrelenting anabolism leads to the cytokine storm, chronic fatigue, chronic inflammation or neurodegenerative diseases. Drugs such as Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism. Similarly, coMeBining Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism.

Post-thaw quality of ram sperm frozen with different concentrations of low-density lipoproteins associated with non-enzymatic antioxidants.

The cryopreservation reduces ram sperm quality, decreasing the pregnancy rate of ewes inseminated with thawed sperm. Hence, we aimed to improve the post-thaw quality of ram sperm replacing egg yolk on Tris-Glucose extender with different concentrations of LDL (2 or 8%), associated with the addition of 10 mM non-enzymatic antioxidants (ascorbic acid, hydroxytoluene butylate, ascorbyl palmitate, and trehalose). Semen samples were collected from six rams, split into different treatments, and frozen. After thawing, kinematic (CASA), structural (propidium iodide and carboxyfluorescein diacetate) and functional (hypoosmotic test) sperm membrane integrity was assessed. Total motility, VCL, and LIN were also assessed in thawed samples during 3 h of incubation (38 °C). The results showed that hydroxytoluene butylate at 10 mM in Tris-Glucose extender with 8% LDL improved velocity parameters immediately post-thaw compared with Tris-Glucose egg yolk extender, as well as prevented the reduction of total motility and VCL after incubation. There was no benefit of adding ascorbic acid and trehalose. Moreover, for the first time, it was shown the motility impairment promoted by ascorbyl palmitate to ram sperm.

Stereoselective synthesis of biphenolate/binaphtolate titanate and zirconate alkoxide species: structural characterization and use in the controlled ROP of lactide.

Well-defined biphenol/binaphtolate group 4 alkoxide salt species [(Ph-Biphen-O)(2)M(O(i)Pr)]Li(THF) (2a, M = Ti; 4a, M = Zr) and [(Ph-binapht-O)(2)M(O(i)Pr)]Li(THF) (2b, M = Ti; 4b, M = Zr) were found to be readily accessible in good yields via alcohol elimination routes and/or substitution reactions from the corresponding pro-ligands Ph-Biphen-OH (1a) and rac-Ph-Binapht-OH (1b). As established via X-ray crystallographic analysis, the molecular structures of the Ti derivatives 2a and 2b consist of Li(+) salts of anionic Ti-O(i)Pr moieties in which the Ti center adopts a distorted tbp geometry and is effectively chelated by two biphenolate/binaphtolate units. Remarkably, the solution and solid state data for salt species 2a,b agree with the sole presence of one diastereomer (with a (Δ, aS, aS)/(Λ, aR, aR) configuration), thus indicating that formation of the Ti and Zr alkoxide complexes 2a,b/4a,b proceeds stereoselectively. In contrast, the neutral biphenolate/binaphtolate Zr complexes (Ph-biphen-O)(2)Zr(THF)(2) (3a) and (Ph-binapht-O)(2)Zr(THF)(2) (3b) were both isolated and X-ray characterized as stereomers in a heterochiral configuration (Δ, aR, aS)/(Λ, aS, aR). The Ti and Zr alkoxide anionic chelates were found to initiate the ROP of rac-lactide in a controlled manner for production of narrowly disperse and ester-end group PLA, as deduced from SEC, kinetic, and MALDI-TOF data. The Zr-O(i)Pr derivatives 4a,b exhibit superior performance to their Ti counterparts (whether regarding activity, polymerization control, or stereoselectivity) to produce narrowly disperse and heterotactically enriched PLA (P(r) = 0.67, PDI < 1.15). The significantly decreased Lewis acidity of the Zr metal center in anions 4a,b (versus neutral analogues) due to the anionic charge and a likely substantial electronic π donation of the four Zr-O(ArO) oxygens to the Zr metal center may rationalize the moderate polymerization activity. Control experiments suggest that the nature of the countercation has little influence on lactide ROP activity and stereocontrol.

The structure of water in p-sulfonatocalix[4]arene.

Tetrasodium p-sulfonatocalix[4]arene exists as a hydrate with approximately 14 water molecules and has three polymorphic modifications, all of which contain a water molecule in the molecular cavity that is engaged in OH···π interactions. Single-crystal neutron structures are reported for two of these three forms and reveal a "compressed" water molecule with short OH bonds. Partial atomic charges and hardness analysis (PACHA) calculations based on the neutron coordinates give an OH···π interaction energy of 6.9-7.5 kJ mol(-1). The PACHA analysis also reveals the dominance of the charge-assisted hydrogen bonds from the Na(+)-coordinated water molecules. The instability of the crystal towards dehydration can be traced to an uncoordinated lattice water site. The remarkable calixarene-Na(+)-hydrate motif is conserved almost unchanged across all three polymorphs. A single-crystal neutron structure is also reported for pentasodium p-sulfonatocalix[4]arene·12H(2)O, which exhibits an intracavity water molecule that is engaged in both OH···π and OH···O hydrogen bonding. The shorter covalent bond to the hydrogen atom that forms the interaction with the aromatic ring is again apparent.

Spontaneous symmetry breaking during self-assembly of a double stranded biphenolate-based Ti(IV)-helicate.

A binuclear Ti(IV)-based helicate synthesized from a symmetric tetrahydroxyheptaphenylene strand was self-assembled in solution and shown to undergo a spontaneous head-to-tail differentiation according to single-crystal X-ray diffraction.