a b s t r a c tA perfect molecular level separating unit for any kind of species to be filtered is on very high demand. In recent years, graphene oxide has emerged as an important material which can filter ions and molecules. This is an emerging field of research which has drawn extensive attention after the work by Nair et al.[1]. Following their work, various research groups started working in this area in last three years. Herein, we briefly review the recent development on graphene oxide membranes. This review is a summary of some very recent results and contributions made so far in this emerging research field. We have discussed recently developed mechanisms and models to understand the transport through GO based membranes. This review begins with a basic background on membrane technology followed by discussion related to developments of carbon materials based membrane technology. At the end we summarize advantages and disadvantages of membranes based on graphene oxide and discuss their future prospective.

Plant activators are compounds, such as analogs of the defense hormone salicylic acid (SA), that protect plants from pathogens by activating the plant immune system. Although some plant activators have been widely used in agriculture, the molecular mechanisms of immune induction are largely unknown. Using a newly established high-throughput screening procedure that screens for compounds that specifically potentiate pathogen-activated cell death in Arabidopsis thaliana cultured suspension cells, we identified five compounds that prime the immune response. These compounds enhanced disease resistance against pathogenic Pseudomonas bacteria in Arabidopsis plants. Pretreatments increased the accumulation of endogenous SA, but reduced its metabolite, SA-O-β-d-glucoside. Inducing compounds inhibited two SA glucosyltransferases (SAGTs) in vitro. Double knockout plants that lack both SAGTs consistently exhibited enhanced disease resistance. Our results demonstrate that manipulation of the active free SA pool via SA-inactivating enzymes can be a useful strategy for fortifying plant disease resistance and may identify useful crop protectants.

Graphene oxide (GO) is widely recognized as a promising material in a variety of fields, but its structure and composition has yet to be fully controlled. We have developed general strategies to control the oxidation degree of graphene-like materials via two methods: oxidation of graphite by KMnO4 in H2SO4 (oGO), and reduction of highly oxidized GO by hydrazine (rGO). Even though the oxygen content may be the same, oGO and rGO have different properties, for example the adsorption ability, oxidation ability, and electron conductivity. These differences in property arise from the difference in the underlying graphitic structure and the type of defect present. Our results can be used as a guideline for the production of tailor-made graphitic carbons. As an example, we show that rGO with 23.1 wt% oxygen showed the best performance as an electrode of an electric double-layer capacitor.

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Transition metals of the fourth row are abundant and cheap compared to those of the fifth and sixth rows. Therefore, by introducing new reactivities with fourth-row metal complexes, it might be possible to replace fifth-and sixth-row metals in some fundamental and important reactions. Catalytic Grignard-type addition of nucleophiles to aldehydes is one such reaction. Grignard reagents are usually prepared from organic halides and magnesium metal, [1] but this procedure results in the unwanted formation of stoichiometric amounts of metal salts. One way to solve this problem is to generate the nucleophiles by CÀH bond activation; [2] however, it has been difficult to promote nucleophilic addition after the CÀH activation step. Although nucleophilic addition of species generated by CÀH activation has been reported using ruthenium, [3] rhodium, [4] palladium, [5] and rhenium [6] catalysts, it has been difficult to catalyze such reactions using fourthrow transition-metal complexes. [7] We report herein that 1) complexes of manganese, a fourth-row transition metal, can be employed for CÀH bond activation of aromatic compounds; 2) insertion of aldehydes into CÀH bonds occurs to give benzyl alcohols; and 3) catalytic transformation is achieved with the manganese complex by the addition of Et 3 SiH.We initially investigated stoichiometric CÀH bond activation and insertion of aldehydes with the manganese complex [MnBr(CO) 5 ]. A mixture of 1-methyl-2-phenyl-1H-imidazole (1 a) and [MnBr(CO) 5 ] in toluene was heated at 100 8C for 5 min, at which point a solution of benzaldehyde (2 a) was added. The mixture was heated at reflux for 10 h to give alcohol 3 in 52 % yield (Scheme 1). Although stoichiometric CÀH bond activation and insertion of the aldehyde occured with [MnBr(CO) 5 ], only a trace amount of 3 was produced with a catalytic amount of the manganese complex.To recycle the manganese complex, 2.0 equiv of triethylsilane (4) was added to the reaction mixture from the beginning. As a result, silyl ether 5 a was obtained in 93 % yield with 5 mol % [MnBr(CO) 5 ]. [8,9] We examined the catalytic activity of several metal complexes using the reaction between 1 a, 2 a, and 4 as a probe. A different manganese complex, [Mn 2 (CO) 10 ], showed similar catalytic activities (82 % yield of 5 a). However, the reaction did not proceed at all with the following metal complexes: [MnCl 2 ], [Mn(acac) 3 ] (acac = acetylacetonate), [{ReBr(CO) 3 (thf)} 2 ], [6]

Nano-confined spaces in nanoporous materials enable anomalous physicochemical phenomena. While most nanoporous materials including metal-organic frameworks are mechanically hard, graphene-based nanoporous materials possess significant elasticity and behave as nanosponges that enable the force-driven liquid–gas phase transition of guest molecules. In this work, we demonstrate force-driven liquid–gas phase transition mediated by nanosponges, which may be suitable in high-efficiency heat management. Compression and free-expansion of the nanosponge afford cooling upon evaporation and heating upon condensation, respectively, which are opposite to the force-driven solid–solid phase transition in shape-memory metals. The present mechanism can be applied to green refrigerants such as H 2 O and alcohols, and the available latent heat is at least as high as 192 kJ kg −1 . Cooling systems using such nanosponges can potentially achieve high coefficients of performance by decreasing the Young’s modulus of the nanosponge.

Pd nanoparticles supported on single layer graphene oxide (Pd-slGO) were prepared by gentle heating of palladium(ii) acetate (Pd(OAc)2) and GO in ethanol that served as a mild reductant of the Pd precursor. Pd-slGO showed a high catalytic performance (TON and TOF = 237 000) in the Suzuki-Miyaura cross-coupling reaction.

Graphite oxide (GO) and its constituent layers (i.e., graphene oxide) display a broad range of functional groups and, as such, continue to attract significant attention for use in numerous applications. GO is commonly prepared using the "Hummers method" or a variant thereof where graphite is treated with KMnO4 and various additives in H2SO4. Despite its omnipresence, the underlying chemistry of such oxidation reactions is not well understood and typically afford results that are irreproducible and, in some cases, unsafe. To overcome these limitations, the oxidation of graphite under Hummers-type conditions was monitored over time using in situ X-ray diffraction (XRD) and in situ X-ray absorption near edge structure (XANES) analyses with synchrotron radiation. In conjunction with other atomic absorption spectroscopy, UV-Vis spectroscopy and elemental analysis measurements, the underlying mechanism of the oxidation reaction was elucidated and the reaction conditions were optimized. Ultimately, methodology for reproducibly preparing GO on large scales using only graphite, H2SO4, and KMnO4 was developed and successfully adapted for use in continuous flow systems. Although graphite oxide (GO) has been known for more than 150 years, its individual layers, often termed graphene oxide, have recently gained extraordinary attention for potential use in a broad range of applications. 1-8 The attraction is due, in part, to the material's high chemical potential, which stems from the myriad functional groups decorated on its surface. GO is typically prepared by treating graphite with a strong oxidizer followed by exfoliation, and many variations