Simple Synthesis of New Mixed Isocyanide-NHC-Platinum(II) Complexes and Their Catalytic Activity

2014 ◽  
Vol 67 (3) ◽  
pp. 469 ◽  
Author(s):  
Christoph Hubbert ◽  
Marcus Breunig ◽  
Kristen J. Carroll ◽  
Frank Rominger ◽  
A. Stephen K. Hashmi
Keyword(s):  
Crystal Structure ◽  
Catalytic Activity ◽  
Structural Data ◽  
Simple Synthesis ◽  
X Ray ◽  
New Family ◽  
Catalytically Active ◽  
Convergent Approach ◽  
New Compounds

Using the new modular and convergent approach to isocyanide-N-hetrocyclic carbene-platinum(ii) complexes, eight new compounds have been synthesised. For three of these, detailed structural data could be obtained by X-ray crystal structure analyses. This new family of organoplatinum complexes is catalytically active for hydrosilylation reactions; styrene and phenylacetylene could be used as substrates; triethylsilane and 1,1,1,3,5,5,5-heptamethyltrisiloxane could be used as reagents. With some of the new platinum pre-catalysts, excellent regioselectivities of up to 98 : 2 could be obtained, and turnover numbers up to 840 were achieved.

scholarly journals Synthesis and catalytic activity of homoleptic lanthanide-tris(cyclopropylethinyl)amidinates

2015 ◽  
Vol 39 (10) ◽  
pp. 7595-7601 ◽  
Author(s):  
Farid M. Sroor ◽  
Cristian G. Hrib ◽  
Liane Hilfert ◽  
Sabine Busse ◽  
Frank T. Edelmann
Keyword(s):  
Crystal Structure ◽  
Catalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type C

New unsolvated, homoleptic lanthanide(iii) tris(cyclopropylethinylamidinate) complexes of the type [c-C3H5–CC–C(NR)2]3Ln (R = iPr, cyclohexyl; Ln = Nd, Sm, Ho) have been prepared and the crystal structure of the holmium derivative [c-C3H5–CC–C(NiPr)2]3Ho has been confirmed by X-ray diffraction.

scholarly journals The Rosetta all-atom energy function for macromolecular modeling and design

2017 ◽  
Author(s):  
Rebecca F. Alford ◽  
Andrew Leaver-Fay ◽  
Jeliazko R. Jeliazkov ◽  
Matthew J. O'Meara ◽  
Frank P. DiMaio ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Energy Function ◽  
Crystal Structure Data ◽  
Structural Data ◽  
X Ray ◽  
The Past ◽  
Biomolecular Modeling ◽  
Macromolecular Modeling ◽  
Atom Energy

AbstractOver the past decade, the Rosetta biomolecular modeling suite has informed diverse biological questions and engineering challenges ranging from interpretation of low-resolution structural data to design of nanomaterials, protein therapeutics, and vaccines. Central to Rosetta’s success is the energy function: amodel parameterized from small molecule and X-ray crystal structure data used to approximate the energy associated with each biomolecule conformation. This paper describes the mathematical models and physical concepts that underlie the latest Rosetta energy function, beta_nov15. Applying these concepts,we explain how to use Rosetta energies to identify and analyze the features of biomolecular models.Finally, we discuss the latest advances in the energy function that extend capabilities from soluble proteins to also include membrane proteins, peptides containing non-canonical amino acids, carbohydrates, nucleic acids, and other macromolecules.

Synthesis, Characterization, and Crystal Structure of Several Novel Acidic Ionic Liquids: 1-ethyl-2-alkyl-benzimidazolium Tetra-Fluoroborate

2013 ◽  
Vol 457-458 ◽  
pp. 139-143 ◽  
Author(s):  
Ming Tian Wang ◽  
Chang Ping Pan ◽  
Wei Peng Gai ◽  
Xiao Xia Lv ◽  
Min Gang Zhai ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ionic Liquid ◽  
Acetic Acid ◽  
Catalytic Activity ◽  
Lamellar Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Ionic Liquid ◽  
Acidic Ionic Liquids ◽  
Good Catalytic Activity

A series of novel acidic ionic liquid: 1-ethyl-2-alkyl-benzimidazolium tetra-fluoroborate (alkyl= Et, Pr-n, Bu-n) were prepared by simple acid-based neutralization of 1-ethyl-2-alkyl-benzimidazole and tetrafluoroboric acid. The compounds were characterized by FTIR spectra, elemental analysis,1HNMR spectra and thermogravimetric analysis. These novel tetra-fluoroborate salts show good catalytic activity to esterification of benzyl alcohol and acetic acid. Furthermore, a crystal of ([H-ebBiBF4) was prepared with the crystal structure and determined by X-ray diffraction analysis. The molecular is of lamellar structure as mainly π electron ring is stacked interleaving between two layers. The results of cation and anion arranged orderly in pair indicate that the coulombic attraction is more dominant. Simultaneously, the weak local hydrogen bonds C-H···F exist in the molecules.

scholarly journals Synthesis and X-ray Crystal Structures of Novel Spiro 1,3-benzoxazine Dimers

2002 ◽  
Vol 2002 (10) ◽  
pp. 473-474 ◽  
Author(s):  
H.Z. Alkhathlan ◽  
M.A. Al-Saad ◽  
H.M. Al-Hazimi ◽  
K.A. Al-Farhan ◽  
A.A. Mousa
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Mass Spectra ◽  
X Ray ◽  
New Compounds

Novel spiro 1,3-benzoxazine dimers are obtained when hydrazones of 2-hydroxyacetophenone are treated with triphosgene. An X-ray crystal structure, and the NMR and mass spectra of these new compounds, are reported and discussed.

scholarly journals Azobenzene-based inhibitors of human carbonic anhydrase II

2015 ◽  
Vol 11 ◽  
pp. 1129-1135 ◽  
Author(s):  
Leander Simon Runtsch ◽  
David Michael Barber ◽  
Peter Mayer ◽  
Michael Groll ◽  
Dirk Trauner ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Catalytic Activity ◽  
Carbonic Anhydrase ◽  
Drug Class ◽  
Carbonic Anhydrase Ii ◽  
Carbonic Anhydrases ◽  
X Ray ◽  
X Ray Crystallography ◽  
Human Carbonic Anhydrase

Aryl sulfonamides are a widely used drug class for the inhibition of carbonic anhydrases. In the context of our program of photochromic pharmacophores we were interested in the exploration of azobenzene-containing sulfonamides to block the catalytic activity of human carbonic anhydrase II (hCAII). Herein, we report the synthesis and in vitro evaluation of a small library of nine photochromic sulfonamides towards hCAII. All molecules are azobenzene-4-sulfonamides, which are substituted by different functional groups in the 4´-position and were characterized by X-ray crystallography. We aimed to investigate the influence of electron-donating or electron-withdrawing substituents on the inhibitory constant K i. With the aid of an hCAII crystal structure bound to one of the synthesized azobenzenes, we found that the electronic structure does not strongly affect inhibition. Taken together, all compounds are strong blockers of hCAII with K i = 25–65 nM that are potentially photochromic and thus combine studies from chemical synthesis, crystallography and enzyme kinetics.

scholarly journals Redetermination of ammonium metavanadate

IUCrData ◽  
2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Aarón Pérez-Benítez ◽  
Sylvain Bernès
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Structural Data ◽  
Ammonium Cation ◽  
Ammonium Metavanadate ◽  
Starting Material ◽  
X Ray ◽  
Hydrogen Bonding Interactions

The crystal structure of ammonium metavanadate, NH4VO3, a compound widely used as a starting material for the synthesis of vanadium and polyoxidovanadate compounds, had been determined twice using single-crystal X-ray data [Syneček & Hanic (1954). Czech. J. Phys. 4, 120–129 (Weissenberg data); Hawthorne & Calvo (1977). J. Solid State Chem. 22, 157–170 (four-circle diffractometer data)]. Its structure is now redetermined at higher resolution using Ag Kα radiation, and the result is compared with the former refinements. Structural data for the polymeric [VO3]∞ chain remain unchanged, while more accurate parameters are obtained for the ammonium cation, improving the description of hydrogen-bonding interactions in the crystal structure.

Interaction of the Components in the {Ce, Gd}-{Ti, Zr}-Sb Systems

2019 ◽  
Vol 289 ◽  
pp. 3-11
Author(s):  
Oleksandr Senchuk ◽  
Roman E. Gladyshevskii
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Ternary Systems ◽  
The Other ◽  
Powder Diffraction Data ◽  
Isothermal Sections ◽  
X Ray ◽  
Ternary Compounds ◽  
New Compounds

The phase equilibria in the ternary systems {Ce, Gd}–{Ti, Zr}–Sb were investigated by means of X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The isothermal sections of the phase diagrams at 600°C were constructed. The formation of three ternary compounds (Ce2Ti7Sb12, Ce3TiSb5, and Gd2Ti11Sb14) was confirmed in the {Ce, Gd}–Ti–Sb systems and no more ternaries were found. The investigation of the {Ce, Gd}–Zr–Sb systems revealed several new ternary compounds and confirmed the known ones. The crystal structure of the new compound Ce0.08(3)Zr1.92(3)Sb was determined from X-ray powder diffraction data. The other new compounds in the Ce–Zr–Sb system were found to have compositions close to ~CeZrSb4and ~Ce2Zr3Sb5. In the Gd–Zr–Sb system the existence of a large homogeneity range was established for the GdZrSb compound along the isoconcentrate 33.3 at.% Sb: Gd1-xZr1+xSb (x= 00.905(18) at 600°C), and a new compound, ~Gd3Zr3Sb14, was discovered. The crystal structures at the boundary compositions of the Gd1-xZr1+xSb phase were refined from X-ray powder diffraction data.

Introducing Molecular Diversity at the C20-position of Pregnenolone by the Formation of Spiro-2-morpholinones

2018 ◽  
Vol 15 (4) ◽  
pp. 541-551
Author(s):  
Guy Bertrand Djigoue ◽  
Donald Poirier
Keyword(s):  
Small Molecules ◽  
Molecular Diversity ◽  
Structural Diversity ◽  
Building Blocks ◽  
Dimensional Representation ◽  
Huge Amount ◽  
X Ray ◽  
3 Dimensional ◽  
New Family ◽  
New Compounds

Aim and Objective: The development of small molecules that can interact with key therapeutic target represents an active field of research. Therefore, new approaches for increasing the molecular diversity of a starting material, such as a natural product, are needed. Herein, the carbonyl group present on a pregnane scaffold, or easily obtained from the oxidation of the corresponding alcohol, was used to obtain a series of diversified steroidal morpholinone derivatives. Materials and Methods: Using chemical synthesis, two levels of molecular diversity were introduced at position 20 of a C21-steroid scaffold. Nuclear magnetic resonance (NMR) spectroscopy and x-ray analysis were next used to characterize the morpholinone derivatives. Results: The C-20 carbonyl of pregnenolone was first transformed into an oxirane that reacted with an amino acid and the resulting amino alcohol was then cyclized to generate different spiro-2-morpholinones. X-ray analysis of one representative compound confirmed the 3-dimensional representation of this new family of diversified steroid derivatives. NMR analysis supported the expected structure and identified key markers of the chiral center configuration found in the 2-morpholinone moiety. Finally, the NH of the morpholinone ring was alkylated, thus increasing structural diversity. Conclusion: Considering the huge amount of building blocks (amino acids, bromobenzyl derivatives and ketones) that are commercially available, the strategy reported herein opens the door to the synthesis of diversified libraries of new compounds.

Zur Synthese und Kristallstruktur von Zinkboratoxiden mit isolierten, trigonal planaren BO3-Baugruppen: Zn5Mn(BO3)2O4 und ZnFe(BO3)O / Synthesis and Crystal Structure of Zinc Borate Oxides Containing Isolated Trigonal Planar BO3 Units: Zn5Mn(BO3)2O4 and ZnFe(BO3)O

1995 ◽  
Vol 50 (10) ◽  
pp. 1450-1454 ◽  
Author(s):  
Silke Busche ◽  
Karsten Bluhm
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Zinc Borate ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Octahedral Sites ◽  
Distorted Octahedral ◽  
New Compounds ◽  
Group D

Single crystals of the new compounds Zn5Mn(BO3)2O4 (A ) and ZnFe(BO3)O (B) were prepared by using a B2O3 flux technique. Zn5Mn(BO3)2O4 is isostructural with Ni5Ti(BO3)2O4 and ZnFe(BO3)O is isotypic with the mineral warwickite. X-ray investigations on single crystals led to (A ) space group D92h -Pbam, a = 926.41(10), b = 1236.67(8), c = 304.55(3) pm, Z = 2, and (B) space group D162h-Pnma, a = 924.62(4), b = 314.1(10), c = 935.3(2) pm, Z = 4. The structure of Zn5Mn(BO3)2O4 (A ) contains four octahedrally coordinated metal sites, one of these statistically occupied by Zn2+ and Mn4+. In the structure of ZnFe(BO3)O the ions Zn2+ and Fe3+ occupy statistically both distorted octahedral sites. Both structures contain isolated BO3 units and oxygen that is not coordinated to boron.

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