Titanocene and ansa-titanocene complexes bearing 2,6-bis(isopropyl)phenoxide ligand(s). Syntheses, characterization and use in catalytic dehydrocoupling polymerization of phenylsilane

2011 ◽  
Vol 76 (1) ◽  
pp. 75-94 ◽  
Author(s):  
Michal Horáček ◽  
Jan Merna ◽  
Róbert Gyepes ◽  
Jan Sýkora ◽  
Jiří Kubišta ◽  
...  
Keyword(s):  
Variable Temperature ◽  
Titanocene Dichloride ◽  
Spectroscopic Methods ◽  
Rotation Barrier ◽  
X Ray Diffraction ◽  
Hindered Rotation ◽  
Catalytic Behavior ◽  
X Ray ◽  
Catalytic Activities ◽  
H Nmr

Aryloxychloro and bis(aryloxy) titanocenes of general formula L2TiCl2–x(OAr′)x where L = η5-C5H5 (x = 1 (1) and 2 (2)), L2 = SiMe2(η5-C5H4)2 (x = 1 (3) and 2 (4)), and Ar′ = 2,6-(CHMe2)2C6H3 were prepared by the reaction of corresponding titanocene dichloride with LiOAr′ and characterized by spectroscopic methods and compound 3 by single crystal X-ray diffraction analysis. The bulky aryloxy ligand in 1 and 3 exerts a hindered rotation around the Ti–O bond on the 1H NMR time scale, resulting in its dynamic behavior in CDCl3 solution. Variable temperature NMR measurements proved the rotation barrier in 3 (ΔG‡298 = 13.9 ± 0.3 kcal/mol) to be lower than that in 1 (ΔG‡298 = 14.7 ± 0.2 kcal/mol) as a consequence of the more open titanocene shell in the ansa-structure of 3. The catalytic behavior of complexes 1–4, [(η5-C5H5)2TiCl2] and [{SiMe2(η5-C5H4)2}TiCl2], was examined in dehydrocoupling polymerization of phenylsilane under comparable conditions, showing a remarkable higher activity for the titanocene complexes with regards to the ansa-titanocene ones. The order of catalytic activities 2 ~ 1 > [(η5-C5H5)2TiCl2] >> [{SiMe2(η5-C5H4)2}TiCl2] ~ 3 ~ 4 reveals the aryloxy ligands to have an enhancing effect on activity in the titanocene series.

Synthesis and X-Ray Crystal Structure of Two Novel Ester Ferrocenophanes

2007 ◽  
Vol 62 (4) ◽  
pp. 605-609 ◽  
Author(s):  
Li Tao ◽  
Yang Bingqin ◽  
Gao Bo
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Elemental Analysis ◽  
3D Structure ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Carbonyl Chloride ◽  
Tof Ms

Two novel ester ferrocenophanes have been prepared by esterification of 1,1′-ferrocenedi(carbonyl chloride) with glycol and 1,4-butanediol, respectively. Both of them have been characterized by IR, elemental analysis, MALDI-TOF MS and 1H NMR spectroscopic methods, and their structures have been elucidated by X-ray diffraction. The intermolecular associations based on C-H···O hydrogen bonds have also been discussed. These molecules are assembled into chains, and the chains are further assembled into a 3D structure through several hydrogen bonds.

BODIPY trimer with 1,3,5-triazine core: Facile synthesis and crystal structure

2021 ◽  
pp. A-H
Author(s):  
Chunhua Huang ◽  
Bin Shen ◽  
Kaili Wang ◽  
Xiaofei Sun
Keyword(s):  
Crystal Structure ◽  
Fluorescence Spectroscopy ◽  
Hirshfeld Surface ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Design And Synthesis ◽  
H Nmr

Trimerization reaction of 8-(4[Formula: see text]-cyanophenyl)-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (CN-BODIPY) led to the isolation of a new triazine-based BODIPY trimer 2,4,6-tris(8[Formula: see text]-phenyl-1[Formula: see text],3[Formula: see text],5[Formula: see text],7[Formula: see text]-tetramethyl-4[Formula: see text],4[Formula: see text]-difluoro-4[Formula: see text]-bora-3a[Formula: see text],4a[Formula: see text]-diaza-s-indacene)-1,3,5-triazine (1). This BODIPY trimer 1 have been characterized by a series of spectroscopic methods including MALDI-TOF mass, 1H NMR, electronic absorption, IR and fluorescence spectroscopy. In particular, the single crystals of 1 have be obtained by slow diffusion of methanol into the solution of this compound in CHCl3. The BODIPY trimer structure of 1 with a triazine core has been directly revealed on the basis of single crystal X-ray diffraction analysis with the intermolecular interactions investigated by Hirshfeld surface analysis. This work will be helpful for the design and synthesis of new multiple BODIPY derivatives with various application.

A multinuclear solid-state magnetic resonance study of silver nitrate triphenylphosphine

2005 ◽  
Vol 83 (10) ◽  
pp. 1721-1730 ◽  
Author(s):  
Se-Woung Oh ◽  
Guy M Bernard ◽  
Roderick E Wasylishen ◽  
Robert McDonald ◽  
Michael J Ferguson
Keyword(s):  
Phase Transition ◽  
Solid State ◽  
Single Crystal ◽  
Silver Nitrate ◽  
Solid Phase ◽  
Variable Temperature ◽  
Spin Coupling ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr

Variable-temperature solid-state 31P, 15N, and 2H NMR spectroscopy, X-ray diffraction, and differential scanning calorimetry studies of the 1:1 adduct of silver nitrate and triphenylphosphine (AgNO3·PPh3) reveal a solid–solid phase transition at 300 K. The principal components of the phosphorus and nitrogen chemical shift tensors for both phases are determined from NMR spectra of MAS and stationary samples. In addition, the indirect spin-spin coupling between phosphorus and the naturally occurring isotopes of silver (107Ag and 109Ag) are resolved. Experimental 2H NMR line shapes for silver nitrate perdeuterated triphenylphosphine are those characteristic of rigid phenyl groups at temperatures above and below the phase-transition temperature. Powder and single-crystal X-ray diffraction data for AgNO3·PPh3 obtained at 193, 295, and 313 K are reported; data obtained at 193 and 295 K are almost identical, but are significantly different from those obtained at 313 K and from an earlier single-crystal X-ray diffraction investigation performed at 298 K. All X-ray studies found that AgNO3·PPh3 crystallizes in the monoclinic form, space group P21/c.Key words: 1:1 silver nitrate triphenylphosphine adduct, solid-state NMR, X-ray diffraction, phase transition.

Synthesis, characterization, and dynamic behaviour of pseudoferrocene complexes

1990 ◽  
Vol 68 (11) ◽  
pp. 1923-1931 ◽  
Author(s):  
Michael D. Clerk ◽  
Michael J. Zaworotko ◽  
Bozena Borecka ◽  
T. Stanley Cameron ◽  
Donald L. Hooper ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Variable Temperature ◽  
Grignard Reagents ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Ring Rotation ◽  
Methyl Phenyl

Carbanion sources (organolithium and Grignard reagents) react with [(mesitylene)2Fe]2+ and [(mesitylene)(Ch)Fe]+ cations (Ch = cyclohexadienyl) to afford neutral Ch2Fe and ChCh′Fe ("pseudoferrocene") complexes, respectively. Addition of R− (R− = methyl, phenyl, benzyl, and t-butyl) occurs stereospecifically via exo addition at an unsubstituted carbon atom of the arene ring. The synthesis and characterization of these complexes is detailed and the structure of bis(η5-exo-6-phenyl-1,3,5-trimethylcyclohexadienyl)iron(II), 3b, has been determined by single crystal X-ray diffraction analysis. 3b crystallizes in the triclinic space group [Formula: see text], with a = 11.947(2), b = 12.784(1), c = 8.865(2), α = 108.59(1)°, β = 108.19(1)°, γ = 84.91(1)°, and Dcalcd 1.227 g cm−3 for Z = 2. Least-squares refinement gave a conventional R value of 0.0452 for 2080 independent observed reflections. The structure reveals that the complex adopts a gauche-eclipsed conformation. The variable temperature (vt) 1H NMR spectra of pseudoferrocenes are interpreted in terms of restricted ring rotation around the ligand—metal—ligand axis. Keywords: arene, cyclohexadienyl, pseudoferrocene, variable temperature NMR, X-ray diffraction.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

Bis(μ-carboxylato)dienerhodium(I) Complexes - Synthesis, Characterization and Catalytic Activity

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1205-1221 ◽  
Author(s):  
Jiří Zedník ◽  
Jan Sedláček ◽  
Jan Svoboda ◽  
Jiří Vohlídal ◽  
Dmitrij Bondarev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffraction Analysis ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray

Dinuclear rhodium(I) η2:η2-cycloocta-1,5-diene (series a) and η2:η2-norborna-2,5-diene (series b) complexes with μ-RCOO- ligands, where R is linear C21H43 (complexes 1a, 1b), CH2CMe3 (2a, 2b), 1-adamantyl (3a, 3b) and benzyl (4a, 4b), have been prepared and characterized by spectroscopic methods. Structures of complexes 2b, 3a and 4a were determined by X-ray diffraction analysis. Complexes prepared show low to moderate catalytic activity in polymerization of phenylacetylene in THF giving high-cis-transoid polymers, but they show only oligomerization activity in dichloromethane.

scholarly journals New Haloterpenes from the Marine Red Alga Laurencia papillosa: Structure Elucidation and Biological Activity

Marine Drugs ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 35
Author(s):  
Mohamed Shaaban ◽  
Ghada S. E. Abou-El-Wafa ◽  
Christopher Golz ◽  
Hartmut Laatsch
Keyword(s):  
Biological Activity ◽  
Crude Extract ◽  
Structure Elucidation ◽  
Antimicrobial Activities ◽  
Red Alga ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Structures ◽  
Terpene Derivatives

Analysis of the air-dried marine red alga Laurencia papillosa, collected near Ras-Bakr at the Suez gulf (Red Sea) in Egypt delivered five new halogenated terpene derivatives: aplysiolic acid (1), 7-acetyl-aplysiol (2), aplysiol-7-one (3), 11,14-dihydroaplysia-5,11,14,15-tetrol (5a), and a new maneonene derivative 6, named 5-epi-maneolactone. The chemical structures of these metabolites were characterized employing spectroscopic methods, and the relative and absolute configurations were determined by comparison of experimental and ab initio-calculated NMR, NOE, ECD, and ORD data, and by X-ray diffraction of 2 and 6. The antimicrobial activities of the crude extract and compounds 1–3, 5a and 6 were studied.

scholarly journals Tautomerisation in 1-(4-Methylphenylazo)naphthalen-2-ol and 2-(4-Methylphenylazo)-4-methylphenol: A Crystallographic and 13C{1H}NMR Study

1999 ◽  
Vol 23 (3) ◽  
pp. 178-179
Author(s):  
Wendy I. Cross ◽  
Kevin R. Flower ◽  
Robin G. Pritchard
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Resonant Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Nmr Study ◽  
Acetic Acid Esters ◽  
Acid Esters ◽  
Equivalent Carbon

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.

scholarly journals Structures, Chemical Conversions, and Cytotoxicity of Tricholopardins C and D, Two Tricholoma Triterpenoids from the Wild Mushroom Tricholoma pardinum

2021 ◽  
Author(s):  
Chen Shi ◽  
Yue-Ling Peng ◽  
Juan He ◽  
Zheng-Hui Li ◽  
Ji-Kai Liu ◽  
...  
Keyword(s):  
Hela Cell ◽  
Single Crystal ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Spectroscopic Methods ◽  
Wild Mushroom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hela Cell Lines ◽  
Mcf 7

AbstractTwo undescribed Tricholoma triterpenoids, namely tricholopardins C (1) and D (2), were isolated from the wild mushroom Tricholoma pardinum. Their structures with absolute configurations were elucidated by spectroscopic methods, as well as the single crystal X-ray diffraction. Compounds 1 and 2 were further obtained by chemical conversions from the known analogues. Compound 1 showed significant cytotoxicity to MCF-7 and Hela cell lines with IC50 values of 4.7 μM and 9.7 μM, respectively. Its mechanism of inducing MCF-7 cell apoptosis was studied briefly. Graphical Abstract

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