Homogeneous aluminum and iron catalysts for the synthesis of organic molecules and biodegradable polymers

The direct C-H functionalization reaction is one of the most efficient strategies by which to introduce new functional groups into small organic molecules. Over time, iron complexes have emerged as versatile catalysts for carbine-transfer reactions with diazoalkanes under mild and sustainable reaction conditions. In this review, we discuss the advances that have been made using iron catalysts to perform C-H functionalization reactions with diazoalkanes. We give an overview of early examples employing stoichiometric iron carbene complexes and continue with recent advances in the C-H functionalization of C(sp2)-H and C(sp3)-H bonds, concluding with the latest developments in enzymatic C-H functionalization reactions using iron-heme-containing enzymes.

Download Full-text

Strategy for the Use of Molecular Oxygen in Organic Synthesis

Synlett ◽

10.1055/s-0040-1707240 ◽

2020 ◽

Cited By ~ 1

Author(s):

Tsuyoshi Taniguchi

Keyword(s):

Molecular Oxygen ◽

Organic Synthesis ◽

Electron Acceptor ◽

Organic Molecules ◽

Bond Formation ◽

Reactive Species ◽

Synthetic Methods ◽

Mitsunobu Reaction ◽

Iron Catalysts ◽

Direct Quenching

Our recent studies on the development of new synthetic methods using molecular oxygen (O2), which is an environmentally friendly oxidant, are described in this Account. The character of O2 as an electron acceptor can be utilized for activation of simple organic molecules to generate reactive species. Such reactive species are applicable to advanced molecular transformation, such as C–C and C–X (X = heteroatom) bond formation, functionalization of inactivated C(sp3)–H, and catalytic Mitsunobu reaction, by avoiding direct quenching of the reactive species by O2.1 Introduction2 Reactions with Iron Catalysts and Oxygen2.1 Reactions Using Redox Hydration of Alkenes2.2 Reactions Using Oxidation of Heteroatoms3 Reactions with tert-Butyl Nitrite and Oxygen4 Conclusion

Download Full-text

Perchlorate Removal in Biodegradable Polymers Bioreactor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.522-524.353 ◽

2014 ◽

Vol 522-524 ◽

pp. 353-356

Author(s):

Fang He ◽

Hai Hong Zhou ◽

Xiu Ju Wang

Keyword(s):

Carbon Source ◽

Biodegradable Polymers ◽

Aqueous Phase ◽

Organic Molecules ◽

Morphological Observation ◽

Batch Experiments ◽

Small Organic Molecules ◽

Perchlorate Reduction ◽

Nitrate Degradation ◽

Optimal Ph

This work evaluates the feasibility of the biodegradable polymers (BDPs) bioreactor concept for removal of perchlorate from groundwater; and the likely impacts of nitrate and pH were also examined. Batch experiments demonstrated clearly that ClO4- was eliminated from the aqueous phase readily under appropriate surface biofilm of enriched mixed consortium on PBS, a new kind of BDPs, with the PBS granules as the sole chemical and physical substrate for the microorganism. Simultaneous perchlorate and nitrate degradation were occurring with the PBS granules degradation to supply conbon source. The optimal pH of perchlorate reduction was at 6.7. Morphological observation indicated the microbes in biofilm decomposed PBS through metabolism and provided carbon source for themselve by releasing small organic molecules.

Download Full-text

High Resolution Replication of Organoclay Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055126 ◽

1982 ◽

Vol 40 ◽

pp. 576-577

Author(s):

W. W. Barker ◽

W. E. Rigsby ◽

V. J. Hurst ◽

W. J. Humphreys

Keyword(s):

Clay Mineral ◽

Organic Molecule ◽

Organic Molecules ◽

X Ray Diffraction ◽

Xrd Pattern ◽

X Ray ◽

Naturally Occurring ◽

Silicate Layers ◽

Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Download Full-text

Direct phase determination in electron crystallography: small organic molecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130468 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1166-1167

Author(s):

Douglas L. Dorset

Keyword(s):

Organic Molecules ◽

Data Sets ◽

Temperature Structure ◽

3D Analysis ◽

Intensity Data ◽

Electron Crystallography ◽

Phase Determination ◽

Measured Intensity ◽

3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

Download Full-text