Adaptability of root morphology and growth of two forage grass species in response to salt stress

The cultivated Echinochloa frumentacea (Roxb.) Link and Echinochloa crusgalli (L.) Beauv. var. mitis (Pursh) Peter are two valuable grass species that are widely used in improving saline-alkali soil. Here we conducted a pot experiment combined with roots morphological analysis to investigate the adaptability of grass roots to saline stress environments, with cultivated E. frumentacea and E. crusgalli being subjected to salt treatments of 0 (CK), 100, 220, and 340 mmoL·L−1. Results indicated that E. frumentacea had longer primary roots with fewer root hairs and lower local branching density than E. crusgalli, with the root volume of E. frumentacea being 1.43 times greater than that of E. crusgalli. The aboveground biomass of both grasses decreased significantly (p < 0.05) with increasing salt concentrations, whereas the root-to-shoot ratio exhibited the opposite trend, suggesting the preferential allocation of photosynthetic products to the roots under salt stress. The total length, surface area, and tip number of fine roots and the growth of coarse roots (d > 2.00 mm) showed significant differences (p < 0.05) between the two grass species. Different concentrations of salt stress had inconsistent effects on the biomass and radial growth of roots for grasses. The cultivated E. frumentacea seems to adopt an adapt strategy of gradually increasing its root thickness, root hairs, and root density under increasing salt stress. E. crusgalli, on the other hand, employed a strategy of increasing root length, maintaining uniform thickness, and developing root hairs

Palladium-Catalyzed Highly Chemo-, Regio-and Stereoselective Synthesis of Eight- to Ten-Membered Lactones from Allenyl 3-Oxoalkanoates and Organic Halides

A highly chemo-, regio-, and stereoselective synthesis of eight-to ten-membered lactones via the coupling cyclization of readily available allenyl 3-oxoalkanoates and organic halides through an anti-pi-allylic palladium intermediate is reported. The yields ranged from moderate to good

Insertion reactions of allenes with transition metal complexes

Recently, allenes have been widely used as starting materials to synthesize various organic compounds and polymeric materials, especially through reactions catalyzed by transition metal catalysts. In many of the catalytic reactions, insertion of allenes is one of the most important elementary steps. In this review, stoichiometric insertion reactions of transition metal complexes with allenes affording well-defined inserted products are summarized, which may help chemists to understand the mechanisms of catalytic reactions of allenes and to design new catalytic reactions of allenes. (C) 2008 Elsevier B.V. All rights reserved

Palladium-Catalyzed Regioselective Cyclopropanating Allenylation of (2,3-Butadienyl)malonates with Propargylic Carbonates and Their Application to Synthesize Cyclopentenones

An efficient and highly regioselective route to synthesize polysubstituted 1,3,4-alkatrien-2-yl cyclopropane derivatives via Pd(0)-catalyzed highly regioselective coupling cyclization of (2,3-butadienyl)malonate or bis(phenylsulfonyl)methane with propargylic carbonates was reported. The reaction proceeded smoothly under neutral conditions to afford the products in 73-96\% yields. The products may be efficiently converted to cyclopentenone derivatives via a catalytic Pauson-Khand reaction under ambient conditions

Rh(I)-catalyzed three-component reaction of 2,3-allenoates, organoboronic acids, and aldehydes. An efficient synthesis of alpha,beta-unsaturated delta-lactones

alpha,beta-Unsaturated delta-lactones were efficiently prepared by an Rh(I)-catalyzed three-component reaction of 2,3-allenoates, organoboronic acids, and aldehydes. The reaction may proceed via a sequential transmetalation, carbometalation of 2,3-allenoates, insertion of aldehydes, and lactonization process. (c) 2007 Elsevier Ltd. All rights reserved

Palladium-Catalyzed Three-Component Cascade Cyclization Reaction of Bisallenes with Propargylic Carbonates and Organoboronic Acids: Efficient Construction of cis-Fused Bicyelo[4.3.0]nonenes

A bicycle built for two: The title reaction affords cis-fused bicyclo[4.3.0]nonenes from readily available 1,5-bisallenes with structurally diverse propargylic carbonates and arylboronic acids (see scheme; X=NTs, C(E¹)₂ with E¹=CO²Bn, SO ²Ph, dba=trans,trans-dibenzylidenacetone). The reaction may involve a sequential oxidative addition, two different types of three carbopalladations, and a Suzuki-type coupling. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA

Electrophilic Cyclization of 2-(2 ',3 '-Allenyl)acetylacetates with Iodine Using Calcium Hydride as the Base

A facile and efficient protocol for the synthesis of 4,5-dihydrofuran derivatives via iodine-mediated cyclization of various 2-(2',3'-allenyl)acetylacetates with CaH2 as the base has been developed. The yields range from moderate to good. The resulting products can be used for further elaboration by palladium-catalyzed coupling reactions

Palladium-Catalyzed Three-Component Reaction of 2,3-Allenyl Amines, Isocyanates, and Organic Halides: A Diversified Assembly of Imidazolidinones

A three-component reaction of 2,3-allenyl amines with isocyanates and organic halides has been developed. Two carbon-nitrogen bonds as well as a carbon-carbon bond were sequentially formed to construct imidazolidinone derivatives in good to excellent yields (see scheme). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Studies on palladium-catalyzed enantioselective cyclization of 3,4-allenylic hydrazines with organic halides

A convenient route to optically active pyrazolidine derivatives from Pd(O)/(R,R)-Bn-BOX-catalyzed enantioselective cyclization of 3,4-allenylic hydrazines in the presence of organic halides has been developed, the ee value is 75-84\%. The absolute configuration of the products was determined by the conversion of one of the products to a known product prepared in this group. The reaction may proceed via the oxidative addition, intermolecular carbometallation of the allene moiety forming a pi-allylic palladium intermediate, and the intramolecular enantioselective allylation. (C) 2008 Elsevier Ltd. All rights reserved

Thermodynamics of Vacuum Chloride Volatilization of Ni, Co, Mn, Li, Al, and Cu in Spent Lithium−Ion Battery

In recent years the chlorination leaching separation process in the field of hydrometallurgy has been developed considerably. However, the development of the chlorination separation process in the field of pyrometallurgy has lagged. In this paper, the thermodynamics of vacuum chlorination volatilization of valuable metals Ni, Co, Mn, Li, Al, and Cu from spent lithium−ion batteries is investigated, and it is found that chlorination helps to achieve the trapping and separation of the singlet metals. With the help of Factsage 8.1, a theoretical map of the stable regions of valuable metal chlorides, the order of separation of each chloride at 10 Pa, and a discussion of the behavior of excess CuCl2 in the system at different temperatures were determined. This paper provides research ideas in the fields of selective separation of alloying elements in the carbothermal reduction products of waste lithium−ion batteries and one−step separation of valuable metals by carbothermal reduction