The prediction of the metal cluster within a coordination polymer or complex, as well as the dimensionality of the resulting polymer or complex (i.e., 0D, 1D, 2D, or 3D), is often challenging. This ...is the case for Phsub.2P(CHsub.2)sub.mPPhsub.2 ligands (1 ≤ m ≤ 8) and CuX salts, particularly for X = I. This work endeavors a systematic statistical analysis combining studies in the literature and new data, mapping the nature of the resulting CuI aggregates with eight different diphoshphines in 2:1, 3:2, 1:1, 2:3, and 1:2 CuI:Phsub.2P(CHsub.2)sub.mPPhsub.2 molar ratios as a function of m, which lead to either pure products or mixtures. Several trends are made relating stoichiometry and chain length to the CuI cluster formed (i.e., globular vs. quasi-planar). Four new X-ray structures were determined: Cusub.3Isub.2(L1)sub.3I, Cusub.3Isub.3(L2)sub.2, Cusub.2Isub.2(L6)sub.2, and Cusub.4Isub.4(L8)sub.2, where m is, respectively, 1, 2, 6, and 8, in which the Cusub.xIsub.y central aggregates adopt triangular bipyramid, diamond, rhomboid, and cubane shaped motifs, respectively. Photophysical measurements assisted the establishment of trends considering the paucity of the crystallographic structures. During this study, it was also found that the 0D-complex Cusub.2Isub.2(Phsub.2P(CHsub.2)sub.5PPhsub.2)sub.2 exhibits thermally activated delayed fluorescence.
The development of sustainable renewable polymers from natural resources has increasingly gained attention from scientists, engineers as well as the general public and government agencies. This ...review covers recent progress in the field of renewable bio‐based monomers and polymers from natural resources: terpenes, terpenoids, and rosin, which are a class of hydrocarbon‐rich biomass with abundance and low cost, holding much potential for utilization as organic feedstocks for green plastics and composites. This review details polymerization and copolymerization of terpenes such as pinene, limonene, and myrcene and their derivatives, terpenoids including carvone and menthol, and rosin‐derived monomers. The future direction on the utilization of these natural resources is discussed.
A review on recent advances in the development of renewable monomers and polymers from natural resources terpenes, terpenoids, and rosin is covered. A variety of polymerization techniques and post‐polymerization modification methods are reviewed in the preparation of sustainable renewable polymers and composites.
Self-Healing Polymers via Supramolecular Forces Herbst, Florian; Döhler, Diana; Michael, Philipp ...
Macromolecular rapid communications.,
February 12, 2013, Letnik:
34, Številka:
3
Journal Article
Recenzirano
As polymers and polymeric materials are “the” smart invention and technological driving force of the 20th century, the quest for self‐healing or self‐repairing polymers is strong. The concept of ...supramolecular self‐healing materials relies on the use of noncovalent, transient bonds to generate networks, which are able to heal the damaged site, putting aspects of reversibility and dynamics of a network as crucial factors for the understanding and design of such self‐healing materials. This Review describes recent examples and concepts of supramolecular polymers based on hydrogen bonding, π–π interactions, ionomers, and coordinative bonds, thus convincingly discussing the advantages and versatility of these supramolecular forces for the design and realization of self‐healing polymers.
This Review describes the concepts of supramolecular polymers with multiple self‐healing properties while utilizing the dynamic and reversible character of hydrogen bonds, π–π interactions, ionomers, and coordinative bonds. Furthermore, the versatility of these reversible dynamic forces and their great challenges for the design of self‐healing polymers are discussed for various examples.
Exfoliated g-Csub.3Nsub.4 is a well-known semiconductor utilized in heterogenous photocatalysis and water splitting. An improvement in light harvesting and separation of photogenerated charge ...carriers may be obtained by polymer doping with sulfur. In this work, we incorporate sulfur into the polymer chain by chemical polymerization of trithiocyanuric acid (Csub.3Nsub.3Ssub.3Hsub.3) to obtain Csub.3Nsub.3Ssub.3. The XRD measurements and TEM images indicated that Csub.3Nsub.3Ssub.3, in contrast to g-Csub.3Nsub.4, does not exist in the form of a graphitic structure and is not exfoliated into thin lamellas. However, both polymers have similar optical properties and positions of the conduction and valence bands. The comparative studies of electrochemical oxygen reduction and hydrogen evolution indicated that the overpotentials for the two processes were smaller for Csub.3Nsub.3Ssub.3 than for g-Csub.3Nsub.4. The RDE experiments in the oxygen-saturated solutions of 0.1 M NaOH have shown that Osub.2 is electrochemically reduced via the serial pathway with two electrons involved in the first step. The spectroscopic experiments using NBT demonstrated that both polymers reveal high activity in the photocatalytic reduction of oxygen to superoxide anion radical by the photogenerated electrons.
This work aims to characterize the haloarchaeal diversity of unexplored environmental salty samples from a hypersaline environment on the southern coast of Jeddah, Saudi Arabia, looking for new ...isolates able to produce polyhydroxyalkanoates (PHAs). Thus, the list of PHA producers has been extended by describing two species of Halolamina; Halolamina sediminis sp. strain NRS_35 and unclassified Halolamina sp. strain NRS_38. The growth and PHA-production were investigated in the presence of different carbon sources, (glucose, sucrose, starch, carboxymethyl cellulose (CMC), and glycerol), pH values, (5-9), temperature ranges (4-65 °C), and NaCl concentrations (100-350 g Lsup.−1). Fourier-transform infra-red analysis (FT-IR) and Liquid chromatography-mass spectrometry (LC-MS) were used for qualitative identification of the biopolymer. The highest yield of PHB was 33.4% and 27.29% by NRS_35 and NRS_38, respectively, using starch as a carbon source at 37 °C, pH 7, and 25% NaCl (w/v). The FT-IR pattern indicated sharp peaks formed around 1628.98 and 1629.28 cmsup.−1, which confirmed the presence of the carbonyl group (C=O) on amides and related to proteins, which is typical of PHB. LC-MS/MS analysis displayed peaks at retention times of 5.2, 7.3, and 8.1. This peak range indicates the occurrence of PHB and its synthetic products: Acetoacetyl-CoA and PHB synthase (PhaC). In summary, the two newly isolated Halolamina species showed a high capacity to produce PHB using different sources of carbon. Further research using other low-cost feedstocks is needed to improve both the quality and quantity of PHB production. With these results, the use of haloarchaea as cell factories to produce PHAs is reinforced, and light is shed on the global concern about replacing plastics with biodegradable polymers.
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