Atomistic simulation of the sol formation during synthesis of organic/inorganic hybrid materials

Atomistic modelling was employed to investigate interactions between the precursors used in preparation of organic/inorganic polymer hybrids. Three molecular systems composed of different kinds of organofunctionalised silanes and an organic polymer in aqueous solution have been simulated, representing various model stages of the hydrolysis reaction during the sol/gel processing. The equilibrium configurations obtained by Molecular Dynamics were analysed in order to elucidate the extent of the hydrogen bonding network and clustering of components within the systems. Diffusion coefficients were obtained to estimate the mobility of the components and the stability of the molecular associations. It has been concluded that the molecular mechanism of the initial stages of the sol/gel process used for preparation of the organic/inorganic hybrids involves clustering of the organofunctionalysed inorganic components as a first step and then progressive hydrolysis as consequent steps. The organic polymer component plays a role of the cluster "wrap" and thus prevents the particles from unlimited growth and precipitation from the solution.     

Bioinspired polymeric materials: in-between proteins and plastics

Chemical and biological researchers are making rapid progress in the design and synthesis of non-natural oligomers and polymers that emulate the properties of natural proteins. Whereas molecular biologists are exploring biosynthetic routes to non-natural proteins with controlled material properties, synthetic polymer chemists are developing bioinspired materials with well-defined chemical and physical properties that function or self-organize according to defined molecular architectures. Bioorganic chemists, on the other hand, are developing several new classes of non-natural oligomers that are bridging the gap between molecular biology and polymer chemistry. These synthetic oligomers have both sidechain and length specificity, and, in some cases, demonstrate capability for folding, self-assembly, and specific biorecognition. Continued active exploration of diverse backbone and sidechain chemistries and connectivities in bioinspired oligomers will offer the potential for self-organized materials with greater chemical diversity and biostability than natural peptides. Taken together, advances in molecular bioengineering, polymer chemistry, and bioorganic chemistry are converging towards the creation of useful bioinspired materials with defined molecular properties.     

Phage as templates for hybrid materials and mediators for nanomaterial synthesis

Genetic engineering of phage provides unprecedented opportunities to build novel nanomaterials by integrating biology, chemistry and materials science principles. By mimicking the evolution process in nature, the phage is used as an information-mining tool to identify specific peptide information that can recognize desired materials at the molecular level. The unique recognition peptides of the phage can direct peptide-mediated mineralization processes to grow many useful nanometer-scale electronic and medical materials. The monodispersity and long rod shape of the phage, bearing specific recognition motifs, enable the organization of various nanomaterials into periodically ordered hierarchical structures that could be useful for electronic, optical and biotechnological applications.     

Organic/inorganic nanohybrids as multifunctional gene delivery systems

In this review, we summarize the rational design and versatile application of organic/inorganic hybrid gene carriers as multifunctional delivery systems. Organic/inorganic nanohybrids with both organic and inorganic components in one nanoparticle have attracted intense attention because of their favorable properties. Particularly, nanohybrids comprising cationic polymers and inorganic nanoparticles are considered to be promising candidates as multifunctional gene delivery systems. In this review, we begin with an introduction of gene delivery and gene carriers to demonstrate the incentive for fabricating nanohybrids as multifunctional carriers. Next, the construction strategies and morphology effects of organic/inorganic hybrid gene carriers are summarized and discussed. Both sections provide valuable information for the design and synthesis of hybrid gene carriers with superior properties. Finally, an overview is provided of the application of nanohybrids as multifunctional gene carriers. Diverse therapies and versatile imaging‐guided therapies have been achieved via the rational design of nanohybrids. In addition to a simple combination of the functions of organic and inorganic components, the performances arising from the synergistic effects of both components are considered to be more intriguing. In summary, this review might offer guidance for the understanding of organic/inorganic nanohybrids as multifunctional gene delivery systems.     

Hydrothermal synthesis and structural characterization of bimetallic organic-inorganic hybrid materials: Copper vanadate-1,4-Carboxy-phenylphosphonate phases

The hydrothermal reactions of V₂O₅, a copper(II) source, 1,4-carboxy-phenylphosphonic acid, a bidentate organonitrogen ligand and HF provided a series of bimetallic organic-inorganic hybrid materials. [Cu(bpy)VO₂(O₂CC₆H₄PO₃)] (1) is one-dimensional, while [Cu(bpa)VO(OH)(O₂CC₆H₄PO₃)] (2) and [Cu(phen)V₂O₄F(O₂CC₆H₄PO₃)] (3) are two-dimensional. In the absence of V₂O₅, a number of copper-organophosphonates were isolated. Compound 4 [Cu(phen)(H₂O)(O₂CC₆H₄PO₃H)] is one-dimensional while [Cu₃(bpy)₂(O₂CC₆H₄PO₃)₂] (5) is two-dimensional. Molecular structures were observed for [CuF(bpy)(H₂O)(HO₂CC₆H₄PO₃H)] (6) and [Cu(bpa)(O₂CC₆H₄PO₃H)]·3H₂O (7·3H₂O).     

Bioinspired FeIIICdII and FeIIIHgII complexes: synthesis, characterization and promiscuous catalytic activity evaluation

In this work we report on the synthesis, crystal structure, and physicochemical characterization of the novel dinuclear [Fe^IIICd^II(L)(μ-OAc)₂]ClO₄·0.5H₂O (1) complex containing the unsymmetrical ligand H₂L = 2-bis[{(2-pyridyl-methyl)-aminomethyl}-6-{(2-hydroxy-benzyl)-(2-pyridyl-methyl)}-aminomethyl]-4-methylphenol. Also, with this ligand, the tetranuclear [Fe₂^IIIHg₂^II(L)₂(OH)₂](ClO₄)₂·2CH₃OH (2) and [Fe^IIIHg^II(L)(μ-CO₃)Fe^IIIHg^II(L)](ClO₄)₂·H₂O (3) complexes were synthesized and fully characterized. It is demonstrated that the precursor [Fe^III₂Hg^II₂(L)₂(OH)₂](ClO₄)₂·2CH₃OH (2) can be converted to (3) by the fixation of atmospheric CO₂ since the crystal structure of the tetranuclear organometallic complex [Fe^IIIHg^II(L)(μ-CO₃)Fe^IIIHg^II(L)](ClO₄)₂·H₂O (3) with an unprecedented {Fe^III(μ-O_phenoxo)₂(μ-CO₃)Fe^III} core was obtained through X-ray crystallography. In the reaction 2 → 3 a nucleophilic attack of a Fe^III-bound hydroxo group on the CO₂ molecule is proposed. In addition, it is also demonstrated that complex (3) can regenerate complex (2) in aqueous/MeOH/NaOH solution. Magnetochemical studies reveal that the Fe^III centers in 3 are antiferromagnetically coupled (J = − 7.2 cm^− 1) and that the Fe^III-OR-Fe^III angle has no noticeable influence in the exchange coupling. Phosphatase-like activity studies in the hydrolysis of the model substrate bis(2,4-dinitrophenyl) phosphate (2,4-bdnpp) by 1 and 2 show Michaelis-Menten behavior with 1 being ~ 2.5 times more active than 2. In combination with k_H/k_D isotope effects, the kinetic studies suggest a mechanism in which a terminal Fe^III-bound hydroxide is the hydrolysis-initiating nucleophilic catalyst for 1 and 2. Based on the crystal structures of 1 and 3, it is assumed that the relatively long Fe^III…Hg^II distance could be responsible for the lower catalytic effectiveness of 2.     

Alkaline inorganic pyrophosphatase and starch synthesis in amyloplasts

The aim of this work was to see if amyloplasts contained inorganic pyrophosphatase. Alkaline pyrophosphatase activity, largely dependant upon MgCl₂ but not affected by 100 M ammonium molybdate or 60–100 mM KCl, was demonstrated in exracts of developing and mature clubs of the spadix of Arum maculatum L. and of suspension cultures of Glycine max L., but not in extracts of the developing bulb of Allium cepa L. The maximum catalytic activity of alkaline pyrophosphatase in the above tissues showed a positive correlation with starch synthesis, and in the first two tissues was shown to exceed the activity of ADPglucose pyrophosphorylase. Of the alkaline pyrophosphatase activity in lysates of protoplasts of suspension cultures of Glycine max, 57% was latent. Density-gradient centrifugation of these lysates showed a close correlation between the distribution of alkaline pyrophosphatase and the plastid marker, nitrite reductase. It is suggested that much, if not all, of the alkaline pyrophosphatase in suspension cultures of Glycine max is located in the plastids.Abbreviations PPase inorganic pyrophosphatase - PPi inorganic pyrophosphate     

Luminescent inorganic mixed borate phosphors materials for lighting

The need of new materials with desirable optical properties has become important in recent years. In particular, a need has emerged for compounds having better luminescence properties in various practical applications. The introduction of rare earth ions as activators improves the luminescence properties of the compounds considerably. Boron is one of the most abundant elements in nature. It readily combines with almost all other elements. In combination with oxygen; it forms borates comprised of various anions such as BO₃³⁻, B₂O₅⁴⁻, etc. Apart from these simple borates, several complex compositions exist involving mixed anions as well as double metal borates, due to the three-fold, or four-fold coordination of borate atoms. Borates intrinsically possesses characteristics that are advantageous for optical materials, which include a wide transparency range, large electronic band gap, good thermal and chemical stability, low preparative temperature, optical stability with good nonlinear characteristics, and an exceptionally high optical damage threshold. The unique crystal structure of borates determines their enhanced ultraviolet light transparency, good nonlinearity, and relatively high resistance against laser-induced damage. Some of these complex borates have interesting luminescence properties that are covered in this review. These include double borates containing rare earths RM₃(BO₃)₄, pentaborates LaMgB₅O₁₀, M₃R₂(BO₃)₄, where M is an alkaline earth, mixed anion borates such as aluminoborate SrAl₂B₂O₇, silicate-borates such as pekovite, SrB₂Si₂O₈, haloborates, M₂B₅O₉X, where M is an alkaline earth and X is a halogen, phosphate borates, and MBPO₅, where M is an alkaline earth. Phosphors based on these compositions find use in various applications such as fluorescence lamps, colour TVs, plasma display panels, high-intensity discharge lamps based on xenon, optically pumped solid-state lasers, eye-safe lasers, and X-ray imaging.     

Phosphorylation from inorganic phosphate and ATP synthesis of sarcoplasmic membranes

The incorporation of inorganic phosphate in the fragmented sarcoplasmic membranes induced by the removal of calcium ions bound to high affinity binding sites at the cytoplasmic surface of the membranes gives rise to the formation of two species of phosphoenzyme. The properties of the phosphoproteins formed depend on the absence or the presence of a gradient of calcium ions across the membranes. The phosphoenzymes differ by the affinity of the protein for phosphate, the enthalpy of formation, the kinetics of phosphate incorporation, and by the sensitivity to ionophores and ADP. In the absence of a calcium gradient less than 0.5 nmol phosphoenzyme per mg protein are formed in media containing less than 5 mM phosphate at pH7 and 10 degrees C. Under the same conditions approximately 2 nmol of phosphoenzyme per mg protein are formed with an initial rate of 0.5 nmol mg-1-s-1 when a calcium gradient exists. When the gradient is abolished by the addition of the ionophore X537A, the level of phosphoprotein drops to the same value as observed in the absence of a gradient. On addition of ADP at concentrations increasing from 0.3 to 10 muM continuous ATP formation is activated to its maximum rate, and simultaneously, the level of phosphoprotein declines. These concentrations of ADP scarcely affect phosphoprotein formed in the absence of a gradient, the phosphoryl residue of which is displaced when the concentration of ADP exceeds 10 micrometer without the formation of an equivalent amount of ATP. Minimum mechanisms for the formation of gradient-independent and gradient-dependent phosphoprotein are discussed.     

Caulerpenyne-colchicine hybrid: synthesis and biological evaluation

The synthesis of an analog of caulerpenyne having a trimethoxyaryl moiety was achieved in 11% overall yield over 11 steps. Its biological activity has been evaluated as inhibitor of in vitro tubulin polymerization or angiogenesis.     

Design and synthesis of new biomimetic materials

In this paper, it is reported that the histidine-silane derivative Boc-His(Boc)-CONH-(CH2)3Si(OEt)3 can be polymerized via the sol-gel method or can be grafted on a silica surface. The obtained organosilicas bear histidine molecules covalently bonded on the inorganic matrix. Their Cu(II) complexes have been evaluated as oxidation catalysts for the conversion of 3,5-di-tert-butylcatechol (DTBC) to 3,5-di-tert-butylquinone (DTBQ) in the presence of dioxygen.     

The molecular path to inorganic materials - Zinc oxide and beyond

In the current article, we present a concept for the synthesis of complex nanoscaled materials. The synthetic strategy involves a stepwise assembly of materials starting from special molecular precursors possessing multiple information. Therefore, the article focuses on a strong pervasion of inorganic materials chemistry, solid-state chemistry and molecular chemistry. The concept introduced is finally highlighted by examples from our current research in the field of zinc oxide materials.     

Use of pulp mill inorganic wastes as alternative liming materials

A laboratory aerobic incubation study was performed during 18 weeks under controlled conditions to assess the effects of applying different doses of pulp mill inorganic wastes on the physical-chemical properties of an acid Dystric Cambissol. Three different inorganic wastes were tested - wood ash, dregs and grits, and an agriculture limestone was used as reference. Results showed that increasing the dose applied of the different inorganic wastes tested always led to significant raises of soil pH at different incubation times demonstrating that its use as alternative-liming materials could be a valid and less expensive option to the use of commercial agricultural limestone. Moreover, no immediate concerns seem to be expected related to soil exchangeable sodium (Na) content, at least for the doses needed to increase soil pH until the targeted value 6.5. Particularly for wood ash a pronounced increase on soil extractable potassium and phosphorous was observed, indicating that besides the liming effect this waste can contribute to improve soil fertility by supplying significant available amounts of these nutrients. Finally, metals do not seem to be a limiting factor for the application to land of these by-products.     

Applications of dendrimers in bio-organic chemistry

Dendrimers represent a new class of highly branched polymers whose interior cavities and multiple peripheral groups facilitate potential applications in biomedicine and bio-organic chemistry. Major advances in the past year were made in the synthesis and study of new carbohydrate, nucleic acid, and peptide dendrimers, as well as in the use of dendrimers as magnetic resonance imaging contrast agents, as agents for cellular delivery of nucleic acids, and as scaffolds for biomimetic systems.     

有机-无机复合材料胶结包膜肥料的研制及评价

应用水基成膜法制备4种有机-无机复合胶结包膜材料,利用圆盘造粒机制备其胶结包膜肥料(B2、PS、F2、F2F),并对其性质进行了测定.性能测试结果表明：胶结包膜肥料成粒率、抗压强度和成膜性由好至差均为B2＞PS＞F2＞F2F.土柱淋洗试验结果表明：B2氮素累积溶出曲线最平缓;48 d内氮素累积溶出率表现为：54.65%(B2)<56.16%(PS)<59.47%(F2)<63.12%(F2F).玉米田间试验结果表明：与等量NPK化肥配施处理相比,4种有机-无机复合材料胶结包膜肥料处理的玉米产量均有所提高,其中B2处理的增产效果最显著(P<0.05),其玉米产量和肥料利用率分别提高了19.72%和20.30%,F2F处理差异不显著,PS和F2处理效果居中且前者好于后者.