scholarly journals Heterometallic CoIIIZnII Schiff Base Catalyst for Mild Hydroxylation of C(sp3)–H Bonds of Unactivated Alkanes: Evidence for Dual Mechanism Controlled by the Promoter

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 209 ◽  
Author(s):  
Oksana Nesterova ◽  
Katerina Kasyanova ◽  
Elena Buvaylo ◽  
Olga Vassilyeva ◽  
Brian Skelton ◽  
...  
Keyword(s):  
Schiff Base ◽  
Nitric Acid ◽  
Schiff Base Complex ◽  
Zinc Powder ◽  
The Novel ◽  
X Ray Diffraction ◽  
Turnover Number ◽  
Metal Centers ◽  
X Ray ◽  
Dual Mechanism

The novel Schiff base complex [CoIIIZnIIL3Cl2]·CH3OH (1) was synthesized by interaction of zinc powder, cobalt(II) chloride and methanol solution of the pre-formed HL in air (HL is the product of condensation of o-vanillin and methylamine) and characterized by IR, UV-Vis and NMR spectroscopy, ESI-MS and single crystal X-ray diffraction analysis. In the heterometallic core of 1 the two metal centers are bridged by deprotonated phenoxy groups of the L− ligands with the cobalt-zinc separation of 3.123 Å. Catalytic investigations demonstrated a pronounced activity of 1 towards mild alkane oxidation with m-chloroperbenzoic acid (m-CPBA) as an oxidant and cis-1,2-dimethylcyclohexane (cis-1,2-DMCH) as the model substrate. The influence of the nature of different promoting agents of various acidities (from HOTf to pyridine) on the catalytic process was studied in detail and a pronounced activity of 1 in the presence of nitric acid promoter was found, also showing a high retention of stereoconfiguration of the substrate (>99% for cis-1,2-DMCH). The best achieved yield of tertiary cis-alcohol based on the oxidant was 61%, with a turnover number (TON) of 198 for nitric acid as promoter. The 18O-incorporations into the alcohols when the reactions were performed under 18O2 atmosphere using acetic and nitric acid promoters, suggest that the cis-1,2-DMCH hydroxylation proceeds by two distinct pathways, a non-stereoselective and a stereoselective one (with and without involvement of a long-lived free carbon radical, respectively). The former dominates in the case of acetic acid promoter and the latter is realized in the case of HNO3 promoter.

scholarly journals Synthesis of the first nickel borate nitrate K7Ni[B18O24(OH)9](NO3)6· (H3BO3)

2019 ◽  
Vol 74 (10) ◽  
pp. 757-764
Author(s):  
Michael Zoller ◽  
Klaus Wurst ◽  
Hubert Huppertz
Keyword(s):  
Stainless Steel ◽  
Nitric Acid ◽  
Hydrothermal Synthesis ◽  
Boric Acid ◽  
Diffraction Data ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Nickel ◽  
Nitrate Anions

AbstractThe novel potassium nickel borate nitrate K7Ni[B18O24(OH)9](NO3)6 ·(H3BO3) was obtained from a simple hydrothermal synthesis in a stainless-steel autoclave at T = 513 K starting with nickel dichloride hexahydrate, and boric and nitric acid with the pH adjusted to 8 by KOH. Single-crystal X-ray diffraction data provided the basis for the structure analysis and refinement. The compound crystallizes in the trigonal space group R3̅ (no. 148) with the lattice parameters a = 1222.29(8) and c = 5478.4(4) pm. Generally, K7Ni[B18O24(OH)9](NO3)6 ·(H3BO3) is comprised of nitrate layers and complex nickel borate layers surrounded by boric acid, nitrate anions, and potassium cations.

Syntheses, Structures, Thermal and Photoluminescence Properties of Two Zn(II) and Cd(II) Coordination Polymers Constructed from Taurine-derived Schiff Base and 4,4’-Bipyridine Ligands

2012 ◽  
Vol 67 (8) ◽  
pp. 774-782 ◽  
Author(s):  
Wei-Ting Guo ◽  
Zhi-Min Miao ◽  
Yun-Long Wang
Keyword(s):  
Schiff Base ◽  
Coordination Polymers ◽  
Tridentate Ligand ◽  
Supramolecular Architecture ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Monodentate Ligand ◽  
Metal Centers ◽  
X Ray ◽  
Ethanesulfonic Acid

Two chain-like coordination polymers, namely, {[Zn(saes)(4,4'-bipy)(H2O)]·H2O}n (1) and {[Cd (Hsaes)2(4,4'-bipy)(H2O)2]·2H2O}n (2), where H2saes=2-(2-hydroxybenzylideneamino)ethanesulfonic acid and 4,4'-bipy=4,4'-bipyridine, have been synthesized and characterized by singlecrystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric and photoluminescence analysis. X-Ray diffraction analyses indicate that 1and 2display octahedral metal centers with N3O3 and N2O4 donor sets, respectively. The Schiff base serves as a common N,O'-tridentate ligand in 1, and as a unique O-monodentate ligand in 2. In the crystal, both 1and 2form a 3D supramolecular architecture by O-H···O, C-H···O interactions or π···π stacking. The thermal and solid-state photoluminescence properties of both complexes have been investigated

Synthesis, Characterization, and Antimicrobial Activities of New Organic-Inorganic Hybird Compound Based on Polyoxovanadate and Metal-Schiff-Base Complex

2015 ◽  
Vol 1105 ◽  
pp. 215-219
Author(s):  
Qiong Wu ◽  
Xiao Lin Ji ◽  
Lu Jing ◽  
Hong Ping Ju ◽  
Hai Wang
Keyword(s):  
Schiff Base ◽  
Human Cancer ◽  
Synergetic Effect ◽  
Schiff Base Complex ◽  
Antimicrobial Activities ◽  
Schiff Base Complexes ◽  
X Ray Diffraction ◽  
Base Complex ◽  
X Ray ◽  
Vis Spectroscopy

The reaction of polyoxovanadate and metal-Schiff base complex resulted in the formation of a new organic-inorganic hybrid compounds with the formula Na2[Mn (Salen)(H2O)2]4[V10O28]·9H2O (1) (salen=N,N’-ethylene-bis (salicylideneiminate). Compound 1 have been structurally characterized by IR, UV-vis spectroscopy and single crystal X-ray diffraction. Crystal data for 1: Triclinic, P-1, a=14.1123(3)Å, b=13.9397(7) Å, c=14.2564(5)Å, α=65.4160(9)°, β=81.3920(6)°, γ=89.5740(7) °. Structural analyses revealed that compound 1 represent a rare example of isopolyoxovanadate based metal-Schiff-base complexes, moreover, this is the first POM based metal Schiff-base complex isolated in aqueous solution medium, which may also propose a green chemical way to the synthesis of POM based hybrid. Compare with isopolyoxovanadate precusor Na6 [V10O28], compound 1 exhibit higher antimicrobial activities against human cancer cell, the phenomenon can be explained by the synergetic effect between POM and Schiff-base complex.

Syntheses and structural studies of η5-pentamethylcyclopentadienyl rhodium(III) and iridium(III) complexes of a Schiff-base expanded porphyrin

2010 ◽  
Vol 14 (01) ◽  
pp. 41-46 ◽  
Author(s):  
Luciano Cuesta ◽  
Vincent M. Lynch ◽  
Jonathan L. Sessler
Keyword(s):  
Schiff Base ◽  
Intramolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Coordination Environment ◽  
Metal Centers ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Intramolecular Hydrogen ◽  
Expanded Porphyrin

Reported here is the synthesis of new binuclear rhodium(III) and iridium(III) semi-sandwich complexes of a Schiff-base expanded porphyrin. Single crystals of these new complexes were subject to X-ray diffraction analysis. The resulting structures revealed that the Schiff-base macrocycle adopts a V-shape in which two {(η5- C 5 Me 5) MCl } ( M = Rh and Ir ) fragments are accommodated within the macrocyclic pocket. The coordination environment of the metal centers is typical to that of "piano stool"-type complexes. The X-ray analyses and complementary NMR studies (carried out in CD 2 Cl 2) provide evidence for the existence of strong intramolecular hydrogen-bonding interactions between the pyrrolic NH protons and the chloride counteranion both in solution and in the solid state.

Two new POM-based compounds modified by lanthanide–Schiff base complexes with interesting NLO properties

2018 ◽  
Vol 74 (11) ◽  
pp. 1370-1377 ◽  
Author(s):  
Xi-Ming Luo ◽  
Chen-Hui Cui ◽  
Jia-Peng Cao ◽  
Qing-Fang Lin ◽  
Yan Xu
Keyword(s):  
Schiff Base ◽  
Nonlinear Optics ◽  
Three Dimensional ◽  
Schiff Base Complex ◽  
Schiff Base Complexes ◽  
Photon Absorption ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Two Photon

Two POM-based lanthanide derivatives, namely {triaqua[2,6-diacetylpyridine bis(semicarbazone)-κ5 O,N,N′,N′′,O′]terbium(III)}-μ-oxido-[tricosa-μ2-oxido-dodecaoxido-μ12-phosphato-dodecamolybdenum(VI)] pentahydrate (1), [Tb(C11H15N7O2)(H2O)3][PMo12O40]·5H2O, and the dysprosium(III) analogue (2), have been isolated successfully by the reaction of Keggin–POM [PMo12O40]3− (abbreviated as PMo12 ), the Ln3+ ion and the Schiff base 2,6-diacetylpyridine bis(semicarbazone) (DAPSC) ligand under hydrothermal conditions. [Ln(DAPSC)(H2O)3][PMo12O40]·5H2O is a PMo12 -supported cluster featuring a lanthanide–Schiff base complex [denoted Ln– L (Schiff base)]. Single-crystal X-ray diffraction analysis reveals that the LnIII ion is in a distorted tricapped trigonal prismatic arrangement, coordinated by six O atoms and three N atoms. Two O atoms and three N atoms are provided by one DAPSC ligand, while the additional O atoms originate from a PMo12 cluster and three water molecules. Hydrogen-bonding interactions between adjacent clusters form an interesting three-dimensional supramolecular structure. The identities of 1 and 2 were characterized by IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction. Interestingly, both compounds possess excellent two-photon absorption (TPA) responses to the third-order nonlinear optics (NLO) (2264 GM for 1 and 941 GM for 2), suggesting that they have potential applications in the field of nonlinear optics (NLO). To our knowledge, 1 and 2 are the first POM-based Ln– L (Schiff base) complexes showing excellent two-photon responses. Meanwhile, the electrochemical properties of both compounds were studied in detail.

scholarly journals The synthesis of a Cu(ii) Schiff base complex using a bidentate N2O2 donor ligand: crystal structure, photophysical properties, and antibacterial activities

RSC Advances ◽  
2019 ◽  
Vol 9 (71) ◽  
pp. 41737-41744 ◽  
Author(s):  
Yaning Guo ◽  
Xiaobing Hu ◽  
Xinli Zhang ◽  
Xiaohua Pu ◽  
Yue Wang
Keyword(s):  
Crystal Structure ◽  
Schiff Base ◽  
Single Crystal ◽  
Schiff Base Ligand ◽  
Photophysical Properties ◽  
Schiff Base Complex ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
Donor Ligand ◽  
X Ray

Reaction of a symmetric compartmental Schiff base ligand (HL) with copper(ii) salt in 2 : 1 M ratio in methanol gave rise to a mononuclear copper(ii) complex, which was characterized by single crystal X-ray diffraction studies.

New Copper Compounds with Antiplatelet Aggregation Activity

2019 ◽  
Vol 15 (8) ◽  
pp. 850-862
Author(s):  
Mirthala Flores-García ◽  
Juan Manuel Fernández-G. ◽  
Cristina Busqueta-Griera ◽  
Elizabeth Gómez ◽  
Simón Hernández-Ortega ◽  
...  
Keyword(s):  
Schiff Base ◽  
Solid State ◽  
Thrombotic Event ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Antiplatelet Aggregation ◽  
Aggregation Activity ◽  
L1 And L2

Background: Ischemic heart disease, cerebrovascular accident, and venous thromboembolism have the presence of a thrombotic event in common and represent the most common causes of death within the population. Objective: Since Schiff base copper(II) complexes are able to interact with polyphosphates (PolyP), a procoagulant and potentially prothrombotic platelet agent, we investigated the antiplatelet aggregating properties of two novel tridentate Schiff base ligands and their corresponding copper( II) complexes. Methods: The Schiff base ligands (L1) and (L2), as well as their corresponding copper(II) complexes (C1) and (C2), were synthesized and characterized by chemical analysis, X-ray diffraction, mass spectrometry, and UV-Visible, IR and far IR spectroscopy. In addition, EPR studies were carried out for (C1) and (C2), while (L1) and (L2) were further analyzed by 1H and 13C NMR. Tests for antiplatelet aggregation activities of all of the four compounds were conducted. Results: X-ray diffraction studies show that (L1) and (L2) exist in the enol-imine tautomeric form with a strong intramolecular hydrogen bond. NMR studies show that both ligands are found as enol-imine tautomers in CDCl3 solution. In the solid state, the geometry around the copper(II) ion in both (C1) and (C2) is square planar. EPR spectra suggest that the geometry of the complexes is similar to that observed in the solid state by X-ray crystallography. Compound (C2) exhibited the strongest antiplatelet aggregation activity. Conclusion: Schiff base copper(II) complexes, which are attracting increasing interest, could represent a new approach to treat thrombosis by blocking the activity of PolyP with a potential anticoagulant activity and, most importantly, demonstrating no adverse bleeding events.

Ten-Vertex Polyhedral Monocarbaborane Chemistry. The Novel High-Yield Formation of the Ten-Vertex closo Compound [6-(PMe2Ph)-closo-1-CB9H9] from the Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11]

1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett
Keyword(s):  
Nmr Spectroscopy ◽  
Diffraction Analysis ◽  
High Yield ◽  
Monoclinic Space Group ◽  
The Novel ◽  
X Ray Diffraction ◽  
Metal Centre ◽  
X Ray ◽  
Yield Formation ◽  
Boiling Toluene

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.

scholarly journals Some Novel Cobalt Diphenylphosphine Complexes: Synthesis, Characterization, and Behavior in the Polymerization of 1,3-Butadiene

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4067
Author(s):  
Giovanni Ricci ◽  
Giuseppe Leone ◽  
Giorgia Zanchin ◽  
Benedetta Palucci ◽  
Alessandra Forni ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
And Behavior

Some novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with (2-methoxyethyl)diphenylphosphine, (2-methoxyphenyl)diphenylphosphine, and 2-(1,1-dimethylpropyl)-6-(diphenylphosphino)pyridine. Single crystals suitable for X-ray diffraction studies were obtained for the first two complexes, and their crystal structure was determined. The novel compounds were then used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene, and their behavior was compared with that exhibited in the polymerization of the same monomer by the systems CoCl2(PnPrPh2)2/MAO and CoCl2(PPh3)2/MAO. Some significant differences were observed depending on the MAO/Co ratio used, and a plausible interpretation for such a different behavior is proposed.

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