scholarly journals Coordination studies of 1,2-bis(diphenylphosphino)ethane with di-μ-hydroxo dinuclear complexes of tungsten(IV) and molybdenum(IV)

2016 ◽  
Vol 81 (1) ◽  
pp. 47-55
Author(s):  
Makoto Minato ◽  
Takashi Ito ◽  
Jian-Guo Ren
Keyword(s):  
31P Nmr ◽  
Product Distribution ◽  
Dinuclear Complex ◽  
Nucleophilic Attack ◽  
Dinuclear Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Phosphine Complexes ◽  
Nmr Data ◽  
Reaction Profile

The new trifluoroethoxo phosphine complexes [Cp2M(?1-dppe)(CF3CH2O)]+ and [Cp2(CF3CH2O)M(?-dppe)MCp2(CF3CH2O)]2+ (M = Mo or W, Cp = ?-C5H5 and dppe = Ph2PCH2CH2PPh2) have been prepared by reaction of cationic di-?-hydroxo dinuclear complex of molybdenocene or tungstenocene [Cp2M(?-OH)2MCp2]2+ with dppe. From the 1H and 31P NMR data, the configurations of the products could be assigned. Furtheremore, X-ray crystallography was used to definitively identify one of the product [Cp2(CF3CH2O)Mo(?-dppe)MoCp2(CF3CH2O)]2+, which crystallizes in space group P21/c(#14) with a = 12.230(5) ?, b = 11.149(5) ?, c = 28.966(7) ?, ? = 101.07(3)?, V = 3876(2) ?3, and Z = 2. It was ascertained that the amount of dppe added to the reaction mixture could influence the product distribution. A mechanism involving initial replacement of the hydroxo ligand by the alkoxo group followed by nucleophilic attack of the phosphine is proposed on the basis of the reaction profile.

Tele-Substitution Reactions in the Synthesis of a Promising Class of Antimalarials

2020 ◽  
Author(s):  
Marat Korsik ◽  
Edwin Tse ◽  
David Smith ◽  
William Lewis ◽  
Peter J. Rutledge ◽  
...  
Keyword(s):  
Heterocyclic Ring ◽  
Ring System ◽  
Substitution Reactions ◽  
Laboratory Notebook ◽  
Polar Solvents ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Core ◽  
Nmr Data

<p></p><p>We have discovered and studied a <i>tele</i>substitution reaction in a biologically important heterocyclic ring system. Conditions that favour the <i>tele</i>-substitution pathway were identified: the use of increased equivalents of the nucleophile or decreased equivalents of base, or the use of softer nucleophiles, less polar solvents and larger halogens on the electrophile. Using results from X-ray crystallography and isotope labelling experiments a mechanism for this unusual transformation is proposed. We focused on this triazolopyrazine as it is the core structure of the <i>in vivo </i>active anti-plasmodium compounds of Series 4 of the Open Source Malaria consortium.</p> <p> </p> <p>Archive of the electronic laboratory notebook with the description of all conducted experiments and raw NMR data could be accessed via following link <a href="https://ses.library.usyd.edu.au/handle/2123/21890">https://ses.library.usyd.edu.au/handle/2123/21890</a> . For navigation between entries of laboratory notebook please use file "Strings for compounds in the article.pdf" that works as a reference between article codes and notebook codes, also this file contain SMILES for these compounds. </p><br><p></p>

scholarly journals Synthesis and X-Ray Crystal Structure of 1,1'-Bis(diphenyphosphino)ferrocene Supported CuSCF3 Complex

2019 ◽  
Vol 31 (8) ◽  
pp. 1877-1880
Author(s):  
Yi Yang ◽  
Gen Luo ◽  
Xia Tong ◽  
Yu-Mei Shu ◽  
Yu-Bing Zheng
Keyword(s):  
31P Nmr ◽  
Monoclinic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
R Factor ◽  
Secondary Interactions ◽  
Short Contacts ◽  
Strong Dipole ◽  
Cuprous Complex ◽  
Aromatic Hydrogen

We report herein the synthesis of CuSCF3 complex supported by 1,1'-bis(diphenyphosphino)ferrocene via deoxygenative reduction of Langlois reagent (CF3SO2Na). This cuprous complex [(dppf)Cu(SCF3)] was fully characterized by elemental analysis and 1H (13C, 19F, 31P) NMR spectra. In addition, the molecular structure of [(dppf)Cu(SCF3)] was established by X-ray crystallography. The crystal of compound 1 crystallizes in monoclinic, space group P21/n with a = 11.4366(9), b = 19.1340(16), c = 14.0625(11) Å, V = 3072.62(2) Å3, Z = 4, Z’ = 0, C35H28CuF3FeP2S, Mr = 719.00 and R-factor = 3.69. The short contacts between the two fluorine atoms of CF3S moiety and aromatic hydrogen of Cp/(Ph) rings were observed with leaving the sterically-congested fluorine untouched which highly resembled to the sibling [(PPh3)2CuSCF3]. These interesting secondary interactions in the crystal lattice were explained by the electrostatic forces in terms of the strong dipole of C-F bonds.

scholarly journals Tris(phosphan)-Nickel(0)-Ethen-Komplexe (dmpe)(PR3)Ni(C2H4). Molekülstruktur des (dmpe)(PØ3 )Ni(C2H4)/ Tris(phosphane)-nickel(0)-ethene Complexes (dmpe)(PR3)Ni(C2H4). Molecular Structure of (dmpe)(PO3)Ni(C2H4)

1984 ◽  
Vol 39 (8) ◽  
pp. 1076-1081 ◽  
Author(s):  
Klaus R. Pörschke ◽  
Richard Mynott ◽  
Carl Krüger ◽  
M. J. Romão
Keyword(s):  
Molecular Structure ◽  
Ligand Exchange ◽  
Crystal And Molecular Structure ◽  
Exchange Reactions ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Data

AbstractSynthesis and properties of tris(phosphane)(ethene)nickel(0) complexes (dmpe)(PR3)Ni(C2H4) (R = CH3(4), c-C6H11(5), and C6H5 (6)) are reported. In solution. 4-6 are thermolabile and undergo ligand exchange reactions affording tetrakis(phosphane)nickel(0 ) and bis(phosphane)- (ethene)nickel(0) complexes. 1H, 13C, and 31P NMR data of 4-6 confirm the tetrahedral geometry around nickel. For 6 , the crystal and molecular structure has been determined by X-ray crystallography.

PLP undergoes conformational changes during the course of an enzymatic reaction

2014 ◽  
Vol 70 (2) ◽  
pp. 596-606 ◽  
Author(s):  
Ho-Phuong-Thuy Ngo ◽  
Nuno M. F. S. A. Cerqueira ◽  
Jin-Kwang Kim ◽  
Myoung-Ki Hong ◽  
Pedro Alexandrino Fernandes ◽  
...  
Keyword(s):  
Conformational Change ◽  
Conformational Changes ◽  
Catalytic Mechanism ◽  
Enzymatic Reaction ◽  
Nucleophilic Attack ◽  
The Novel ◽  
X Ray ◽  
X Ray Crystallography ◽  
Starting Point ◽  
High Level

Numerous enzymes, such as the pyridoxal 5′-phosphate (PLP)-dependent enzymes, require cofactors for their activities. Using X-ray crystallography, structural snapshots of the L-serine dehydratase catalytic reaction of a bacterial PLP-dependent enzyme were determined. In the structures, the dihedral angle between the pyridine ring and the Schiff-base linkage of PLP varied from 18° to 52°. It is proposed that the organic cofactor PLP directly catalyzes reactions by active conformational changes, and the novel catalytic mechanism involving the PLP cofactor was confirmed by high-level quantum-mechanical calculations. The conformational change was essential for nucleophilic attack of the substrate on PLP, for concerted proton transfer from the substrate to the protein and for directing carbanion formation of the substrate. Over the whole catalytic cycle, the organic cofactor catalyzes a series of reactions, like the enzyme. The conformational change of the PLP cofactor in catalysis serves as a starting point for identifying the previously unknown catalytic roles of organic cofactors.

Synthese Und Kristallstrukturen Von Chlorometallaten [M = V(III), Mo(V)]

2001 ◽  
Vol 56 (8) ◽  
pp. 759-764 ◽  
Author(s):  
Soheila Chitsaz ◽  
Effat Iravani ◽  
Jochen Pauls ◽  
Bernhard Neumüller
Keyword(s):  
Ir Spectroscopy ◽  
Membered Ring ◽  
Dinuclear Complex ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Independent Molecules ◽  
Triclinic Form

[(THF)2LiCl2VCl2(THF)2] (1) and [Li(THF)4][OMoCl4(THF)] (2) can be prepared by the reactions of VCI3 with LiCl in THF and of Li(H)PtBu with OM0 CI4 in THF, respectively. 1 and 2 were characterized by IR spectroscopy, MS spectrometry (2) and X-ray crystallography. 1 can be obtained in two modifications depending on the temperature of crystallization. At -30 °C a triclinic form, 1a, was isolated from THF solution with one unique molecule per asymmetric unit. However, at 20 °C, 1b crystallized in the monoclinic space group P2/c. It possesses four independent molecules per asymmetric unit. According to the structure analyses 1 consists of a dinuclear complex with a planar LiCl2V four-membered ring while 2 consists of seperate ions [Li(THF)4]+ and [OMoCl4(THF)]-

scholarly journals Synthetic and Structural Study of peri-Substituted Phosphine-Arsines

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7222
Author(s):  
Brian A. Chalmers ◽  
D. M. Upulani K. Somisara ◽  
Brian A. Surgenor ◽  
Kasun S. Athukorala Arachchige ◽  
J. Derek Woollins ◽  
...  
Keyword(s):  
Decomposition Product ◽  
31P Nmr ◽  
31P Nmr Spectroscopy ◽  
Dispersion Forces ◽  
State Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Donor Acceptor ◽  
Tertiary Arsine

A series of phosphorus-arsenic peri-substituted acenaphthene species have been isolated and fully characterised, including single crystal X-ray diffraction. Reactions of EBr3 (E = P, As) with iPr2PAcenapLi (Acenap = acenaphthene-5,6-diyl) afforded the thermally stable peri-substitution supported donor–acceptor complexes, iPr2PAcenapEBr23 and 4. Both complexes show a strong P→E dative interaction, as observed by X-ray crystallography and 31P NMR spectroscopy. DFT calculations indicated the unusual As∙∙∙As contact (3.50 Å) observed in the solid state structure of 4 results from dispersion forces rather than metallic interactions. Incorporation of the excess AsBr3 in the crystal structure of 3 promotes the formation of the ion separated species [iPr2PAcenapAsBr]+Br− 5. A decomposition product 6 containing the rare [As6Br8]2– heterocubane dianion was isolated and characterised crystallographically. The reaction between iPr2PAcenapLi and EtAsI2 afforded tertiary arsine (BrAcenap)2AsEt 7, which was subsequently lithiated and reacted with PhPCl2 and Ph2PCl to afford cyclic PhP(Acenap)2AsEt 8 and acyclic EtAs(AcenapPPh2)2 9.

Synthesis and structure of isocorrole metal complexes

2009 ◽  
Vol 13 (02) ◽  
pp. 256-265 ◽  
Author(s):  
Jun-ichiro Setsune ◽  
Aki Tsukajima ◽  
Naho Okazaki
Keyword(s):  
Metal Complexes ◽  
Metal Coordination ◽  
Dinuclear Complexes ◽  
X Ray ◽  
X Ray Crystallography

gem-dimethylisocorrole gave four-coordinate Ni (II) and Cu (II) complexes, five-coordinate (chloro) Fe (III) and (chloro) Mn (III) complexes, and six-coordinate (chloro)(pyridinato) Rh (III) complex in moderate to good yields. The dinuclear complexes such as the μ-oxo-diiron(III) complex and tetracarbonyldirhodium(I) complex were also prepared. The structures of these mononuclear and dinuclear complexes were determined by X-ray crystallography. These structures are very similar to those of the corresponding metaloporphyrins but the presence of the sp3-meso carbon allows tilting of the pyrrole rings so as to adapt itself to various metal coordination geometries.

Syntheses, characterization, and X-ray crystal structures of diorganotin(IV) derivatives of 2-pyridinethiolato-N-oxide

2003 ◽  
Vol 81 (10) ◽  
pp. 1070-1075 ◽  
Author(s):  
Chunlin Ma ◽  
Junhong Zhang ◽  
Rufen Zhang
Keyword(s):  
Crystal Structure ◽  
Stacking Interactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Data ◽  
Π Stacking ◽  
Oxide Crystal ◽  
Distorted Trigonal Bipyramid ◽  
Π Stacking Interaction ◽  
Derivatives Of

The diorganotin(IV) dichloride reacts with sodium 2-pyridinethiolato-N-oxide in a 1:1 ratio to produce [Me2SnCl(2-SpyO)] (1), [Et2SnCl(2-SpyO)] (2), [Bu2SnCl(2-SpyO)] (3), [Ph2SnCl(2-SpyO)] (4), and [(PhCH2)2SnCl(2- SpyO)] (5). The new complexes have been characterized by elemental analysis and IR and NMR (1H, 119Sn, and 13C) spectroscopy. On the basis of 119Sn NMR data the effective coordination number in solution is five. The structures 1 and 4 have been confirmed by X-ray crystallography. Crystals of 1 are triclinic with space group P[Formula: see text] and those of 4 are monoclinic, P21/n. The tin environment is a distorted trigonal bipyramid with the Cl and oxygen atoms in apical positions. Both complexes exhibit strong π–π stacking interactions. Key words: diorganotin, π–π stacking interaction, 2-pyridinethiolato-N-oxide, crystal structure.

scholarly journals New Tetramic Acid Derivatives From the Deep-Sea-Derived Fungus Penicillium sp. SCSIO06868 With SARS-CoV-2 Mpro Inhibitory Activity Evaluation

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoyan Pang ◽  
Weihao Chen ◽  
Xin Wang ◽  
Xuefeng Zhou ◽  
Bin Yang ◽  
...  
Keyword(s):  
Deep Sea ◽  
Optical Rotation ◽  
Ionization Mass ◽  
Tetramic Acid ◽  
Specific Optical Rotation ◽  
One Dimensional ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Data ◽  
Main Protease

Three new tetramic acid derivatives (1–3) and a new polyketide (4) along with eight known compounds (5–12) were isolated from cultures of the deep-sea-derived fungus Penicillium sp. SCSIO06868. Four new structures were elucidated by analysis of one-dimensional/two-dimensional nuclear magnetic resonance (NMR) data and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were established by X-ray crystallography analysis and comparison of the experimental and reported electronic circular dichroism (ECD) values or specific optical rotation. Compound 3 exhibited potent, selective inhibitory activities against Staphylococcus aureus and methicillin-resistant S. aureus with minimum inhibitory concentration values of both 2.5 μg/ml. Also, compound 3 showed weak antiviral activity against severe acute respiratory syndrome coronavirus 2 main protease, which was responsible for the coronavirus disease 2019 pandemic.

Oxidative Abbaureaktionen des homonuklearen Cobalthydridclusters [(η5-Cp*)Co]3H4 / Oxidative Degradation Reactions of the Homonuclear Cobalt Hydride Cluster [(η5-Cp*)Co]3H4

1995 ◽  
Vol 50 (4) ◽  
pp. 448-459 ◽  
Author(s):  
Jörg J. Schneider ◽  
Richard Goddard ◽  
Carl Krüger
Keyword(s):  
Crystal Structures ◽  
Oxidative Degradation ◽  
Dinuclear Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Degradation Reactions ◽  
Mononuclear Complexes ◽  
Metal Metal ◽  
Inorganic Substrates ◽  
Cobalt Compounds

The homonuclear cobalt cluster [(η5-Cp*)Co]3H4 2 reacts with various organic and inorganic substrates with complete degradation of the cluster core to afford mainly mononuclear organometallic cobalt compounds. Thus, whereas reaction of the cluster with CO, NO or alkynes results in the retention of the Co3 ring, the cluster reacts with Br2, I2, I2/CO , I2/ P(C 2H5)3, CCl4, HCI3, (CH2)2Br2, Hacac, CH2Br2, (C6H5CO)OOC(CH3)3, HBF4, and BrCN to give mononuclear complexes or bridged dinuclear complexes without a metal-metal bond. In all cases formal oxidation of the metal center is observed. The crystal structures of six organocobalt complexes have been determined by X-ray crystallography.

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