Inclusion properties of hydroxy host compounds

Inclusion compounds can be defined as those in which one type of molecule is able to enclose another molecule (usually smaller) within its structure, leaving the bonding systems of both components unchanged. The molecular network and the enclosed species are usually referred to as the "host" and "guest" respectively. The ability of four hydroxyl-containing molecules to form inclusion compounds was studied. Each of these molecules has a tetrahedral carbon or silicon atom bonded to an hydroxyl group and shielded by two or three aromatic moieties. The bulkiness of these molecules prevents them from crystallizing in a close-packed fashion while the hydroxyl groups enable them to participate in hydrogen bonding. The formation and characterisation by single crystal X-ray diffraction methods of two non-porous α-phase compounds and eighteen inclusion compounds have been described. The inclusion compounds were divided into four classes : Class A consisted of compounds of 1, 1,2,2-tetraphenylethane-1,2-diol, Class B consisted of compounds of triphenylmethanol, Class C consisted of compounds of triphenylsilanol and Class D consisted of compounds of tri-1-naphthylsilanol. A number of guest compounds were chosen. Most had at least one atom which could act as an acceptor in a hydrogen bond. Hydrogen bonding (host-host, host-guest or a combination of these) proved to be the greatest stabilizing force in these compounds. The shape and size of the cavities available for guests were analysed by means of volume calculations. The thermal decomposition of the inclusion compounds was studied by Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC), to determine the forces holding the guest within the structure and the changes in the host lattice as the guest was desorbed. X-ray powder diffraction methods were also used to confirm phase changes that occurred with guest loss. In addition, Thermogravimetry was used to determine the activation energy of the guest desorption process. 1, 1,2,2-Tetraphenylethane-1,2-diol was shown to include 3,5-lutidine preferentially from mixtures of 2,6- and 3,5-lutidine, provided that the mole fraction of 3,5-lutidine exceeded 0.30. Triphenylsilanol was selective to ethanol from equimolar mixtures of ethanol and other simple alcohols. Ethanolic solutions of up to 40%(w /w) water also yielded only the 4: 1 triphenylsilanol•ethanol complex. Host-guest interactions were quantified using the method of atom-pair potentials. The position of the guest molecule was varied to allow a minimum potential energy to be calculated. Comparison across a series of related inclusion compounds showed a qualitative correlation between the enthalpy of guest release, ΔH (measured by DSC), and the minimum potential energy of the guest within the crystal structure

Benzoic acid–3,4-bis­[(pyridin-3-ylmeth­yl)amino]­cyclo­but-3-ene-1,2-dione (1/2)

In the title co-crystal, C16H14N4O2·2C7H6O2, the 3,4-bis­[(pyridin-3-ylmeth­yl)amino]­cyclo­but-3-ene-1,2-dione squareamide mol­ecules assemble into chains along the b axis via N—H⋯O hydrogen bonds. The benzoic acid mol­ecules then hydrogen bond to the pyridine rings via O—H⋯N hydrogen bonds, supported by weaker C—H⋯O hydrogen bonds, forming extended ribbons. The asymmetric unit consists of a half squareamide mol­ecule, sitting on a special position around a twofold axis, and one benzoic acid mol­ecule on a general position

Reactions of halogens with Pt(II) complexes of N-alkyl- and N,N-dialkyl-Nʹ -benzoylthioureas: oxidative addition and formation of an I₂ inclusion compound

The treatment of cis-[PtII(L1a/b-S,O)2] complexes of N,N-diethyl- (HL1a) and N,N-di(n-butyl)-N'-benzoylthiourea (HL1b) with I2 or Br2 in chloroform, leads to rapid oxidative addition to yield several geometric isomers of [PtIV(L-S,O)2X2] (X = I, Br); the reactions can be monitored by 195Pt NMR and UV-visible spectrophotometry. The products cis-[PtIV(L1a-S,O)2I2] 6 and cis-[PtIV(L1a-S,O)2Br2] 7, which have been isolated and structurally characterized, are the first-reported crystal structures of complexes of Pt(IV) with this class of ligand. Molecules of 6 pack such that the I–Pt–I axes are essentially aligned, with unusually close nearest-neighbour iodide contacts (3.553(1) A˚ ). These short I···I intermolecular interactions lead to infinite chains of weakly connected molecules in crystals of the compound. No such interactions are evident in the corresponding crystals of 7. Reaction of the Pt(II) complex of N-propyl-N'-benzoylthiourea (H2L2a) cis-/trans-[PtII(H2L2a-S)2Br2] with Br2 also results in oxidative addition, to yield trans-PtIV(H2L2a-S)2Br4 9. By contrast, treatment of cis-/trans-[PtII(H2L2a-S)2I2] with I2 does not lead to an oxidative addition product, yielding instead an interesting iodine inclusion compound of PtII, trans-[PtII(H2L2a-S)2I2]·I2 8. In 8, short intermolecular I···I distances of 3.453(1) A˚ between I2 and coordinated iodide ions in trans-[PtII(H2L2a-S)2I2] molecules, result in infinite chains of weakly linked trans-[PtII(H2L2a-S)2I2] ···I2 groups in the lattice. However, the empirically estimated bond order of 0.75 for the included I2 molecules does not support the possible existence of discrete tetraiodide ions (I42−) in the lattice of compound 8

An analysis of partial efficiencies of energy utilisation of different macronutrients by barramundi (Lates calcarifer) shows that starch restricts protein utilisation in carnivorous fish

This study examined the effect of including different dietary proportions of starch, protein and lipid, in diets balanced for digestible energy, on the utilisation efficiencies of dietary energy by barramundi (Lates calcarifer). Each diet was fed at one of three ration levels (satiety, 80 % of initial satiety and 60 % of initial satiety) for a 42-d period. Fish performance measures (weight gain, feed intake and feed conversion ratio) were all affected by dietary energy source. The efficiency of energy utilisation was significantly reduced in fish fed the starch diet relative to the other diets, but there were no significant effects between the other macronutrients. This reduction in efficiency of utilisation was derived from a multifactorial change in both protein and lipid utilisation. The rate of protein utilisation deteriorated as the amount of starch included in the diet increased. Lipid utilisation was most dramatically affected by inclusion levels of lipid in the diet, with diets low in lipid producing component lipid utilisation rates well above 1·3, which indicates substantial lipid synthesis from other energy sources. However, the energetic cost of lipid gain was as low as 0·65 kJ per kJ of lipid deposited, indicating that barramundi very efficiently store energy in the form of lipid, particularly from dietary starch energy. This study defines how the utilisation efficiency of dietary digestible energy by barramundi is influenced by the macronutrient source providing that energy, and that the inclusion of starch causes problems with protein utilisation in this species

Synthesis and inclusion of S-aryl alkylthiosulfinates as stable allicin mimics

S-Aryl alkylthiosulfinates showing aromatic rings with varying electronic demand have been prepared by oxidation of the corresponding disulfide, the latter prepared using new one-pot methodology involving thiol oxidation with 1-chlorobenzotriazole. Whereas thiosulfinates with electron-withdrawing substituents in the aromatic ring were unstable towards isolation, those with a releasing substituent in the para-position have shown good stability as potential allicin mimics and one of them (p-OMe) has been characterised as its inclusion compound in the cyclodextrin, TRIMEB, by X-ray crystallography

A compendium of raw material digestibilities for barramundi, Lates calcarifer

A series of experiments were conducted to examine the nutrient and energy digestibility of a suite of diets and specific test raw materials when fed to juvenile (179 to 439g) barramundi, Lates calcarifer. Each of the diets was prepared using a twin-screw extruder to mimic modern aquafeed manufacturing processes. Each of the diets was fed to juvenile barramundi for a minimum of a week to allow acclimation to the diet before the faeces were collected using stripping methods. A broad range of digestible nutrient and energy values among the different raw materials were observed, with protein digestibilities ranging from 36% to 106% and energy digestibilities ranging from 36% to 93%. This range in nutritional values of the different raw materials provides substantial utility in allowing the formulation of diets on a digestible nutrient and energy basis across the Asia Pacific region. These results also provide critical data to help underpin the replacement of both fishmeal and fish oil in barramundi diets

Marginal efficiencies of long chain-polyunsaturated fatty acid use by barramundi (Lates calcarifer) when fed diets with varying blends of fish oil and poultry fat

An experiment was conducted with barramundi (Lates calcarifer) juveniles to examine the marginal efficiency of utilisation of long chain-polyunsaturated fatty acids (LC-PUFA). A series of five diets with blends of fish (anchovy) oil and poultry fat (F100:P0, F60:P40, F30:P70, F15:P85, F0:P100) were fed to 208. ±. 4.1. g fish over a 12-week period. The replacement of fish oil with poultry fat had no impact on growth performance (average final weight of 548.3. ±. 10.2. g) or feed conversion (mean. =. 1.14. ±. 0.02). Analysis of the whole body composition showed that the fatty acid profile reflected that of the fed diet. However it was also shown that there was a disproportional retention of some fatty acids relative to others (notably LOA, 18:2n-6 and LNA, 18:3n-3). By examining the body mass independent retention of different fatty acids with differential levels of intake of each, the marginal efficiencies of the use of these nutrients by this species were able to be determined. The differential retention of fatty acids in the meat was also examined allowing the determination of oil blending strategies to optimise meat n-3 LC-PUFA levels. © 2015 Elsevier B.V

Children’s Perspectives of Play and Learning for Educational Practice

Play as a learning practice increasingly is under challenge as a valued component of early childhood education. Views held in parallel include confirmation of the place of play in early childhood education and, at the same time, a denigration of the role of play in favor for more teacher-structured and formal activities. As a consequence, pedagogical approaches towards play, the curriculum activities that constitute play, and the appropriateness of play in educational settings, have come under scrutiny in recent years. In this context, this study investigates children’s perspectives of play and how they understand the role of play and learning in their everyday activities. This article reports on an Australian study where teacher-researchers investigated child-led insights into what counts as play in their everyday classroom activities. Children (aged 3–4 years) described play as an activity that involved their active participation in “doing” something, being with peers, and having agency and ownership of ideas. Children did not always characterize their activities as “play”, and not all activities in the preschool program were described as play. The article highlights that play and learning are complex concepts that may be easily dismissed as separate, when rather they are deeply intertwined. The findings of this study generate opportunities for educators and academics to consider what counts as “play” for children, and to prompt further consideration of the role of play as an antidote to adult centric views of play.Lady Gowrie QLD Health Wellbeing and Happiness Program of QUT’s Children and Youth Research CentrePeer Reviewe

Inclusion of Hydroxycinnamic Acids in Methylated Cyclodextrins: Host-Guest Interactions and Effects on Guest Thermal Stability

There is ongoing interest in exploiting the antioxidant activity and other medicinal properties of natural monophenolic/polyphenolic compounds, but their generally low aqueous solubility limits their applications. Numerous studies have been undertaken to solubilize such compounds via supramolecular derivatization with co-crystal formation with biocompatible coformer molecules and cyclodextrin (CD) complexation being two successful approaches. In this study, eight new crystalline products obtained by complexation between methylated cyclodextrins and the bioactive phenolic acids (ferulic, hydroferulic, caffeic, and p-coumaric acids) were investigated using thermal analysis (hot stage microscopy, thermogravimetry, differential scanning calorimetry) and X-ray diffraction. All of the complexes crystallized as ternary systems containing the host CD, a phenolic acid guest, and water. On heating each complex, the primary thermal events were dehydration and liberation of the respective phenolic acid component, the mass loss for the latter step enabling determination of the host-guest stoichiometry. Systematic examination of the X-ray crystal structures of the eight complexes enabled their classification according to the extent of inclusion of each guest molecule within the cavity of its respective CD molecule. This revealed three CD inclusion compounds with full guest encapsulation, three with partial guest inclusion, and two that belong to the rare class of ‘non-inclusion’ compounds

Aqueous Solution Equilibria and Spectral Features of Copper Complexes with Tripeptides Containing Glycine or Sarcosine and Leucine or Phenylalanine

Copper(II) complexes of glycyl-L-leucyl-L-histidine (GLH), sarcosyl-L-leucyl-L-histidine (Sar-LH), glycyl-L-phenylalanyl-L-histidine (GFH) and sarcosyl-L-phenylalanyl-L-histidine (Sar-FH) have potential anti-inflammatory activity, which can help to alleviate the symptoms associated with rheumatoid arthritis (RA). From pH 2–11, the MLH, ML, MLH-1 and MLH-2 species formed. The combination of species for each ligand was different, except at the physiological pH, where CuLH-2 predominated for all ligands. The prevalence of this species was supported by EPR, ultraviolet-visible spectrophotometry, and mass spectrometry, which suggested a square planar CuN4 coordination. All ligands have the same basicity for the amine and imidazole-N, but the methyl group of sarcosine decreased the stability of MLH and MLH-2 by 0.1–0.34 and 0.46–0.48 log units, respectively. Phenylalanine increased the stability of MLH and MLH-2 by 0.05–0.29 and 1.19–1.21 log units, respectively. For all ligands, 1H NMR identified two coordination modes for MLH, where copper(II) coordinates via the amine-N and neighboring carbonyl-O, as well as via the imidazole-N and carboxyl-O. EPR spectroscopy identified the MLH, ML and MLH-2 species for Cu-Sar-LH and suggested a CuN2O2 chromophore for ML. DFT calculations with water as a solvent confirmed the proposed coordination modes of each species at the B3LYP level combined with 6-31++G**