scholarly journals Exopolyhedral Ligand Orientation Controls Diastereoisomer in Mixed-Metal Bis(Carboranes)

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 519 ◽  
Author(s):  
Antony P. Y. Chan ◽  
Georgina M. Rosair ◽  
Alan J. Welch
Keyword(s):  
New Species ◽  
Mixed Metal ◽  
Steric Crowding ◽  
Ligand Orientation ◽  
A Minor ◽  
Derivatives Of

Heterobimetallic derivatives of a bis(carborane), [μ7,8-(1′,3′−3′-Cl-3′-PPh3-closo-3′,1′,2′-RhC2B9H10)-2-(p-cymene)-closo-2,1,8-RuC2B9H10] (1) and [μ7,8-(1′,3′−3′-Cl-3′-PPh3-closo-3′,1′,2′-RhC2B9H10)-2-Cp-closo-2,1,8-CoC2B9H10] (2) have been synthesised and characterised, including crystallographic studies. A minor co-product during the synthesis of compound 2 is the new species [8-{8′-2′-H-2′,2′-(PPh3)2-closo-2′,1′,8′-RhC2B9H10}-2-Cp-closo-2,1,8-CoC2B9H10] (3), isolated as a mixture of diastereoisomers. Although, in principle, compounds 1 and 2 could also exist as two diastereoisomers, only one (the same in both cases) is formed. It is suggested that the preferred exopolyhedral ligand orientation in the rhodacarboranes in the non-observed diastereoisomers would lead to unacceptable steric crowding between the PPh3 ligand and either the p-cymene (compound 1) or Cp (compound 2) ligand of the ruthenacarborane or cobaltacarborane, respectively.

scholarly journals Avocado-Derived Biomass: Chemical Composition and Antioxidant Potential

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 100
Author(s):  
Minerva C. García-Vargas ◽  
María del Mar Contreras ◽  
Irene Gómez-Cruz ◽  
Juan Miguel Romero-García ◽  
Eulogio Castro
Keyword(s):  
Chemical Composition ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Nutritional Properties ◽  
Aqueous Fraction ◽  
Extraction Solvent ◽  
Main Components ◽  
A Minor ◽  
Derivatives Of

Avocado has become fashionable due to its great organoleptic and nutritional properties. It is consumed as a fresh product and it is also processed to obtain salad oil and guacamole. In all cases, the only usable portion is the pulp. Therefore, to be a more sustainable and profitable agribusiness, it is important to recognize which compounds from the peel and the stone waste can be converted into valuable bio-products. Therefore, their chemical composition was determined according to the National Renewable Energy Laboratory, the total phenolic content by the Folin-Ciocalteu method and the antioxidant properties by the FRAP and TEAC assays. The main components of the peel and stone were acid-insoluble lignin (35.0% and 15.3%, respectively), polymeric sugars (23.6% and 43.9%, respectively), and the aqueous extractives (15.5% and 16.9%, respectively). Both biomasses contain lipids and protein, but a minor proportion (<6%). The valorization of lignin and sugars is of interest given the high content; stones are a rich source of glucose (93.2% of the polymeric fraction), which could be used to obtain biofuels or derivatives of interest. The extractive fraction of the peel contained the highest number of phenolic compounds (4.7 g/100 g biomass), mainly concentrated in the aqueous fraction (i.e., 87%) compared to the ethanol one, which was subsequently extracted. It correlated with major antioxidant activity and, therefore, the peel can be applied to obtain antioxidants and water can be used as an environmentally friendly extraction solvent.

New species of Trichogramma Westwood (Hymenoptera: Trichogrammatidae) associated with lepidopterous eggs in Brazil

Zootaxa ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 1 ◽  
Author(s):  
R. B. QUERINO ◽  
R. A. ZUCCHI
Keyword(s):  
New Species ◽  
Anagasta Kuehniella ◽  
Factitious Host ◽  
A Minor

Four new species of Trichogramma are described: Trichogramma bertii n. sp. from Glena sp., a geometrid of silvicultural importance; Trichogramma esalqueanum n. sp. from Mechanitis lysimnia eggs, a minor pest of tomato and Heliconius erato phyllis; Trichogramma iracildae n. sp. from eggs of Calpodes ethlius; and Trichogramma pratissolii n. sp. collected from Anagasta kuehniella trap eggs (factitious host).

A survey for potential biological control agents of Pereskia aculeata Miller (Cactaceae) in Brazil reveals two new species of Horismenus Walker (Hymenoptera: Eulophidae)

Zootaxa ◽  
2017 ◽  
Vol 4272 (3) ◽  
pp. 430
Author(s):  
TIAGO G. PIKART ◽  
VALMIR A. COSTA ◽  
CHRISTER HANSSON ◽  
SANDRA C. DE CRISTO ◽  
MARCELO D. VITORINO
Keyword(s):  
Biological Control ◽  
New Species ◽  
Ornamental Plant ◽  
Biological Control Agents ◽  
Weed Species ◽  
Sechium Edule ◽  
Two New Species ◽  
Minor Crop ◽  
A Minor

This paper deals with the description of two new species of Horismenus Walker (Hymenoptera: Eulophidae) from Brazil, parasitoids of larvae of Adetus analis (Haldeman) (Coleoptera: Cerambycidae). Both species are similar to Horismenus steirastomae (Girault), a species that also parasitizes cerambycids. Adetus analis is a pest of Sechium edule (Jacq.) Swartz (Cucurbitaceae), a minor crop in Brazil, Argentina and U.S.A., but also feeds in stems of Pereskia aculeata Miller (Cactaceae), an ornamental plant that has become a problematic weed species in Africa, where it was introduced. The two new Horismenus species are described, diagnosed, and compared to H. steirastomae. 

Three new species of Lepraria (Ascomycota, Stereocaulaceae) containing fatty acids and atranorin

2006 ◽  
Vol 38 (6) ◽  
pp. 503-513 ◽  
Author(s):  
štěpánka SLAVÍKOVÁ-BAYEROVÁ ◽  
Alan ORANGE
Keyword(s):  
Fatty Acids ◽  
New Species ◽  
Compound A ◽  
Three New Species ◽  
A Minor ◽  
Minor Compound

Three new species of Lepraria, L. celata, L. humida, and L. sylvicola, are described from Europe. They each possess a finely granular unstratified thallus containing fatty acids and atranorin, but can be distinguished from each other by the type of fatty acids present and by their ecology. Anthraquinones are present in subthalline hyphae of L. humida and L. sylvicola, and are also reported for L. atlantica. Toensbergianic acid can be produced by L. jackii as a minor compound. A key is presented to species of Lepraria containing fatty acids and atranorin as major substances.

Synthesis and characterization of phosphinimine-substituted trifluoro- or trichloro-p-benzoquinones and their cationic Rh(I) complexes. The crystal and molecular structure of 3,5,6-trichloro-2-(triphenylphosphinimino)-p-benzoquinone

1996 ◽  
Vol 74 (11) ◽  
pp. 2378-2385 ◽  
Author(s):  
Jin Li ◽  
Kattesh V. Katti ◽  
Ronald G. Cavell ◽  
A. Alan Pinkerton ◽  
Herbert Nar
Keyword(s):  
Crystal And Molecular Structure ◽  
Molar Absorptivity ◽  
Electron Acceptors ◽  
Synthesis And Characterization ◽  
Chelate Complexes ◽  
Imine Nitrogen ◽  
Nitrogen Donor ◽  
Steric Crowding ◽  
Derivatives Of

Reaction of tetrafluoro- or tetrachloro-p-benzoquinone with silylated phosphoranimines R2R′P=NSiMe3 (R = Ph, Me) yields very highly colored monosubstituted derivatives of the p-quinone that act as two-electron acceptors showing clean, reversible CV traces. The molar absorptivity values are typical of dyes. These ligands also form chelate complexes with Rh(I) precursors using the quinone oxygen and the imine nitrogen donor sites. One of the quinone derivatives, 3,5,6-trichloro-2-(triphenylphosphinimino)-p-benzoquinone, has been structurally characterized. The iminated quinone shows a normal P=N bond length (1.597(2) Å) and P-N-C angle (P-N-C(3) 132.7(2)°). The N—C(3) bond, 1.327(3) Å, is a little shorter as is expected for the establishment of a conjugated structure between the phosphinimine substituent and the quinone ring. Some steric crowding pushes the Cl and N substituents on the quinone ring out of the plane of the ring. Key words: quinones, phosphinimines, fluorine, chlorine, rhodium.

scholarly journals Selective hepatic uptake of synthetic glycoproteins: mannosaminated ribonuclease A dimer and serum albumin.

1979 ◽  
Vol 74 (4) ◽  
pp. 495-509 ◽  
Author(s):  
G Wilson
Keyword(s):  
Serum Albumin ◽  
Reductive Amination ◽  
Hepatic Uptake ◽  
Ribonuclease A ◽  
Liver Uptake ◽  
Lysine Residues ◽  
Minor Site ◽  
Pancreatic Ribonuclease A ◽  
A Minor ◽  
Derivatives Of

The influence of mannose-containing oligosaccharides on the tissue uptake of glycoproteins has been examined with synthetic glycoconjugates. Oligosaccharides obtained from the acetolysis of bakers' yeast mannan have been coupled to the lysine residues of the cross-linked dimer of bovine pancreatic ribonuclease A and of human serum albumin by reductive amination with cyanoborohydride. 14C-labeled derivatives of the two proteins containing two to four mannopyranose residues per 10,000 mol wt were administered intravenously to rats. There was selective (70-80%) uptake of these derivatives by the liver within 10-15 min after injection. A minor site of uptake was the spleen. The extent of hepatic uptake was a function of the number and size of the mannooligosaccharide residues coupled. With the nonglycosaminated derivatives the liver uptake was less than 5%. Related studies have shown that mannose-containing glycoproteins are taken up by both the endothelial and Kupffer cells of the liver; thus, reductive mannosamination may provide a means of directing to these cells proteins of potential therapeutic interest.

Axial Ligand Effects in Sterically Strained Porphyrins: A Crystallographic Study of Five- and Six-coordinated Metal Complexes of 2,3,7,8,12,13,17,18-Octaethyl-5,10,15,20-tetranitroporphyrin

1998 ◽  
Vol 02 (02) ◽  
pp. 107-121 ◽  
Author(s):  
MATHIAS O. SENGE
Keyword(s):  
High Spin ◽  
Mutual Influence ◽  
Structural Data ◽  
Axial Ligand ◽  
The Novel ◽  
X Ray Crystallography ◽  
Axial Ligands ◽  
Metal Derivatives ◽  
Ligand Orientation ◽  
Derivatives Of

Porphyrins with steric hindrance at the periphery are known to exhibit severely non-planar macrocycle conformations. Among other dodecasubstituted porphyrins, the title compound has been studied widely and shows a typical saddle-distorted macrocycle. The specific conformation of the porphyrin leads to the formation of distinct cavities on both sides of the macrocycle. Compared to planar porphyrins this should increase steric interactions between the macrocycle and axial ligands in five- and six-coordinated metal derivatives. In order to study the influence of different axial ligands on the conformation (or vice versa) a variety of five- and six-coordinated metal derivatives of 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetranitroporphyrin (oetnp) were prepared and their conformation investigated by X-ray crystallography. Structural data for Zn II oetnp (L) where L is imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole and 3,5-lutidine clearly indicated that a mutual influence exists between axial ligands and non-planar porphyrins. An asymmetric macrocycle distortion and axial ligand orientation was found in the sterically hindered 2- and 4-methylimidazole derivatives. The presence of four electron-withdrawing nitro-groups led to the formation of the novel polymeric porphyrins ( Zn II oetnp )n and ( Co II oetnp )n where polymer formation was achieved via the utilization of nitro oxygen atoms as axial ligands to the metal centre of neighbouring porphyrins. The structure of the six-coordinated Ni II oetnp ( pyr )2 (where pyr is pyridine) yielded first structural data on neutral, non-planar, high-spin Ni ( II ) porphyrins. A comparison with the respective low-spin Ni II oetnp clearly showed that a change to the high-spin form leads to a less non-planar macrocycle conformation further proving that spin state changes can have a profound effect on the conformation in distorted porphyrins.

scholarly journals New records of ostracods and ammonites from the Aalenian (mainly Concavum Zone) of the Zollernalb (Swabian Alb, SW Germany)

Zitteliana ◽  
2021 ◽  
Vol 95 ◽  
pp. 1-55
Author(s):  
Norbert Wannenmacher ◽  
Volker Dietze ◽  
Matthias Franz ◽  
Günter Schweigert
Keyword(s):  
New Species ◽  
New Records ◽  
Incertae Sedis ◽  
A Minor ◽  
Swabian Alb ◽  
Ostracod Species ◽  
Zonal Boundary

The lithostratigraphy and ammonite/ostracod biostratigraphy and the accompanying fauna of several sections and outcrops around the Hohenzollern (Zollernalb, SW Germany), ranging from the topmost Opalinuston Formation (uppermost Lower Aalenian) to the basal Wedelsandstein Formation (lowermost Lower Bajocian) are described and analyzed. The study of ostracods from 41 samples from the Aalenian and Lower Bajocian of the Heiligenbach, Hausterberg and Roschbach sections has yielded approximately 4,100 specimens. Significant changes in the ostracod assemblage occur at the base of the Lower Aalenian “Comptum” Subzone, at the Bradfordensis/Gigantea subzonal boundary, at the Bradfordensis/Concavum zonal boundary and at the Aalenian/Bajocian boundary (Concavum/Discites zones). A minor change occurs above the Calceola-Bank within the Concavum Zone. The following new ostracod species are described: Cytheropterina crassicostatasp. nov., Eucytherura ebertisp. nov. and Eucytherura foveolatasp. nov. In addition, 15 presumably new species are briefly described; 10 ‘incertae sedis’ taxa are figured, but left in open nomenclature. The ammonite faunas of the Inopernabank and Konglomeratbank beds (Upper Aalenian, Bradfordensis Zone, Gigantea Subzone) as well as the ammonite faunas from the Calceolabank and Rostrote Kalkbank beds (Upper Aalenian, Concavum Zone, Concavum Subzone, cavatum biohorizon) are described and correlated with those of other areas.

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