- Nickel complexes as efficient catalysts in multicomponent synthesis of tetrahydropyridine derivatives
-
Ni(Salen) complexes as an efficient, homogeneous catalysts revealed a catalytic activity toward the one-pot synthesis of tetrahydropyridine derivatives through the pseudo five-component reactions of aromatic aldehydes, aromatic amines, and β-ketoesters in ethanol at room temperature. Mild reaction conditions, good yields, high diastereoseletivity, operational simplicity, and the absence of tedious separation procedures, clean reaction profiles, high atom economy, inexpensive starting materials, and environmentally benign catalyst are the key advantages of the present MCRs protocol.
- Yankin, Andrei N.,Dmitriev, Maksim V.
-
supporting information
p. 3481 - 3489
(2020/08/13)
-
- Syntheses, structures and electrochemical properties of ruthenium(II/III) complexes with tetradentate Schiff base ligands
-
Three unsymmetrical tetradentate Schiff base ligands, H2salipn, H2salipn-Br4 and H2salipn-Cl2, have been synthesized from the typical condensation reactions of treating 1,2-diaminopropane with salicylaldehyde, 3,5-dibromosalicylaldehyde and 5-chlorosalicylaldehyde, respectively. Treatment of [RuCl2(PPh3)3] with one equivalent of H2salipn or H2salipn-Br4 in the presence of triethylamine in tetrahydrofuran (THF) afforded the corresponding ruthenium(III) complexes [RuIIICl(PPh3)(salipn)] (1) and [RuIIICl(PPh3)(salipn-Br4)] (2). Interaction of [RuHCl(CO)(PPh3)3] with one equivalent of H2salipn-Cl2 or H2salipn-Br4 under the same conditions led to isolation of ruthenium(II) complexes [RuII(CO)(PPh3)(salalipn-Cl2)] (3) and [RuII(CO)(PPh3)(salalipn-Br4)] (4), respectively, in which one of the imine bonds was nucleophilically attacked by hydride to result in the formation of a mixed imine-amine ligand. The molecular structures of 1?1.5CH2Cl2, 2, 3?0.5CH2Cl2 and 4 have been determined by single-crystal X-ray crystallography. The electrochemical properties of 1–4 were also investigated. Their cyclic voltammograms displayed quasi-reversible Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples with Eo ranging from 0.67 to 1.05 V and 0.74 to 0.80 V vs. Ag/AgCl (0.1 M), respectively. (Figure presented.).
- Ji, Jiao,Chen, Xin,Wang, Chang-Jiu,Jia, Ai-Quan,Zhang, Qian-Feng
-
p. 480 - 490
(2019/02/26)
-
- Phenoxazinone synthase activity of two iron(III) complexes comprising the same Schiff base ligand: Biomimetic functional model and mechanistic investigation
-
A new 4,4′-bipyridine (4,4′-byp) mediated 1D- polymeric FeIII complex (complex 1) of Schiff base ligand H2L, a 1:2 condensation product of 1,2-diaminopropane and salicylaldehyde, has been synthesized. Complex 1 is structurally characterized by single crystal X-ray diffraction. A phenoxo bridged dinuclear FeIII complex (complex 2) of analogous ligand has been synthesized also. Dioxygen activation in terms of Phenoxazinone synthase activity using o-aminophenol (OAPH) as a model substrate catalyzed by both the complexes are thoroughly investigated here. ESI-MS spectral study reveals that polynuclear complex 1 dissociates into mononuclear units while dissolve in methanol during catalytic study. The kinetic study illustrates that both the complexes have well competence towards o-aminophenol oxidation where dinuclear FeIII species demonstrate higher activity than mononuclear intermediate species. Important finding from the mass spectral and electrochemical study provide significant information of the mechanistic pathway of the functioning phenoxazinone synthase like activity of synthesized iron complexes.
- Chatterjee, Sourav,Sukul, Dipankar,Banerjee, Priyabrata,Adhikary, Jaydeep
-
p. 105 - 112
(2018/02/14)
-
- Synthesis, structure and catalytic alcohol oxidation by ruthenium(III) supported by Schiff base and triphenylphosphine ligands
-
Treatment of [RuCl2(PPh3)3] with two equiv. bi-dentate Schiff base N,O-LH-Cl (N,O-LH-Cl = 2[(3-chloro-phenylimino)-methyl]-phenol) or N,O-LH-NO2 (N,O-LH-NO2 = 2[(4-nitro-phenylimino)-methyl]-phenol) in the presence of triethylamine afforded cis-[RuCl(PPh3)(κ2-N,O-L-Cl)2] (1) and trans-[RuCl(PPh3)(κ2-N,O-L-NO2)2]·Et2O (2), respectively. Reactions of [RuCl2(PPh3)3] and equal equiv. tetra-dentate Schiff bases gave corresponding ruthenium(III) complexes [RuCl(PPh3)(salen)] (3) (H2salen = N,N′-disalicylidene-1,2-ethanediamine), [RuCl(PPh3)(salipn)]·2CH2Cl2 (4) (H2salipn = N,N′-disalicylidene-1,2-(1-methyl)ethanediamine), [RuCl(PPh3)(salpn)]·CH2Cl2 (5) (H2salpn = N,N′-disalicylidene-1,2-propanediamine), [RuCl(PPh3)(salphen)]·CH2Cl2 (6) (H2salphen = N,N′-disalicylidene-1,2-phenyldiamine), [RuCl(PPh3)(saltoln)]·CH2Cl2 (7) (H2saltoln = N,N′-disalicylidene-1,2-tolyldiamine) and [RuCl(PPh3)(salcyn)] (8) (H2salcyn = N,N′-disalicylidene-(R,R)-1,2-cyclohexanediamine). The molecular structures of complexes 1–5 and 7 have been determined by single-crystal X-ray crystallography. The catalytic oxidation properties of ruthenium(III) complexes 1–8 were tested towards alcohols in the presence of N-methylmorpholine-N-oxide.
- Tang, Li-Hua,Wu, Fule,Lin, Hui,Jia, Ai-Quan,Zhang, Qian-Feng
-
p. 212 - 218
(2018/04/02)
-
- A new Cu-Zn heteronuclear schiff base complex: Synthesis, structure, and antimicrobial activity
-
A new Cu-Zn heteronuclear complex, [CuZnCl2L], where L is the dianionic form of N,N-bis(salicylidene)propane-1,2-diamine, has been prepared and characterized by elemental analyses, IR, and single-crystal X-ray crystallographic determination. The crystal of the complex is monoclinic: space group P21/c, a = 12.195(5), b = 8.009(3), c = 18.082(7) A, β = 93.745(6)°, V = 1762.3(12) A3, Z = 4. The Cu atom is coordinated by two phenolate O and two imine N atoms of the Schiff base ligand, forming a square planar geometry. The Zn atom is coordinated by two phenolate O atoms of the Schiff base ligand and two Cl atoms, forming a tetrahedral geometry. The effect of the Schiff base ligand and the complex on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.
- Li, Qing-Bin,Xue, Ling-Wei,Yang, Wei-Chun,Zhao, Gan-Qing
-
p. 822 - 825
(2013/05/21)
-
- Synthesis, X-ray crystallography, thermal studies, spectroscopic and electrochemistry investigations of uranyl Schiff base complexes
-
Some tetradentate salen type Schiff bases and their uranyl complexes were synthesized and characterized by UV-Vis, NMR, IR, TG, C.H.N. and X-ray crystallographic studies. From these investigations it is confirmed that a solvent molecule occupied the fifth position of the equatorial plane of the distorted pentagonal bipyramidal structure. Also, the kinetics of complex decomposition by using thermo gravimetric methods (TG) was studied. The thermal decomposition reactions are first order for the studied complexes. To examine the properties of uranyl complexes according to the substitutional groups, we have carried out the electrochemical studies. The electrochemical reactions of uranyl Schiff base complexes in acetonitrile were reversible.
- Asadi, Zahra,Shorkaei, Mohammad Ranjkesh
-
p. 344 - 351
(2013/04/10)
-
- Cycloaddition reactivity studies of first-row transition metal-azide complexes and alkynes: An inorganic click reaction for metalloenzyme inhibitor synthesis
-
The studies described herein focus on the 1,3-dipolar cycloaddition reaction between first-row transition metal-azide complexes and alkyne reagents, i.e. an inorganic variant of the extensively used "click reaction". The reaction between the azide complexes of biologically-relevant metals (e.g., Fe, Co and Ni) found in metalloenzyme active sites and alkyne reagents has been investigated as a proof-of-principle for a novel method of developing metalloenzyme triazole-based inhibitors. Six Fe, Co and Ni mono-azide complexes employing salen- and cyclam-type ligands have been synthesized and characterized. The scope of the targeted inorganic azide-alkyne click reaction was investigated using the electron-deficient alkyne dimethyl acetylenedicarboxylate. Of the six metal-azide complexes tested, the Co and Ni complexes of the 1,4,8,11-tetrametyl-1,4,8,11-tetraazacyclotetradecane (Me 4cyclam) ligand showed a successful cycloaddition reaction and formation of the corresponding metal-triazolate products, which were crystallographically characterized. Moreover, use of less electron deficient alkynes resulted in a loss of cycloaddition reactivity. Analysis of the structural parameters of the investigated metal-azide complexes suggests that a more symmetric structure and charge distribution within the azide moiety is needed for the formation of a metal-triazolate product. Overall, these results suggest that a successful cycloaddition reaction between a metal-azide complex and an alkyne substrate is dependent both on the ligand and metal oxidation state, that determine the electronic properties of the bound azide, as well as the electron deficient nature of the alkyne employed.
- Evangelio, Emi,Rath, Nigam P.,Mirica, Liviu M.
-
experimental part
p. 8010 - 8021
(2012/08/08)
-
- Synthesis and characterization of some hetero binuclear NiII Schiff base complexes
-
Metal complexes of Schiff base ligands derived from N,N′- ethylenebis(salicylaldimine) and N,N′-1,2-propylenebis(salicylaldimine) were used to synthesize a series of hetero binuclear complexes. The general composition of the complexes is MaL.MbL′, where Ma = Ni, M b = Rb or Cs, L = N,N′-1,2-ethylenebis(salicylaldimine) or N,N′,2-propylenebis(salicylaldimine), L′ = deprotonated o-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, 1-nitroso-2-naph-thol, 8-hydroxyquinoline. The complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, infrared spectra and UV-Visible spectra. The metal chelate of Schiff base acts as bidentate ligand and coordinates through the phenolic oxygen atoms. The hetero binuclear Schiff base complexes were screened for their antibacterial activity against bacteria Escherichia coli MTCC-739, Staphylococcus aureus MTCC-96 and for antifungal activity against fungus Candida albicans MTCC-227.
- Kumari, Priya,Prakash,Prakash
-
-
- New compounds of tetradentate Schiff bases with vanadium(IV) and vanadium(V)
-
A new range of potentially tetradentate proligands, H2L, derived from aromatic aldehydes and ketones and aliphatic diamines has been prepared. Their vanadyl(IV) and vanadyl(V) complexes [VO(L)] and [VO(L)]+, and also some adducts [VO(L)→VO(L)]+, have been synthesized. The structures of four selected complexes have been determined and it is shown that these must be a result of both steric and electronic factors that make prediction of conformation and stacking difficult. The adducts [VO(L)→VO(L)]+ have structures that persist in solution in dichloromethane, where they can undergo redox chemistry, but they apparently dissociate into their component complexes in the donor solvent acetonitrile. The Royal Society of Chemistry 1999.
- Choudhary, Nosheen F.,Connelly, Neil G.,Hitchcock, Peter B.,Leigh, G. Jeffery
-
p. 4437 - 4446
(2007/10/03)
-
- Synthesis and characterization of cobalt(II) chelates of N,N'-ethylene bis-salicylaldimine and related quadridentate ligands
-
Cobalt(II) complexes with a series of as many as sixteen SALEN type of quadridentate ligands derived by condensing substituted carbonyls and different diamines have been synthesized and characterized by IR, 1N NMR, molar conductivity, magnetic susceptibility measurements and electronic spectral data. Subnormal magnetic moment values infer the presence of dimeric structure for the present complexes. However, electronic spectral data suggest a square planar structure in solution, possibly due to the monomeric structure. Infrared spectral data suggest the bonding of ligands through two ortho phenolic oxygen and two azomethine nitrogen atoms. The electrochemical behaviour of these complexes has been studied by cyclic voltammetry. Additional phenolic groups present in these complexes are useful for the facile synthesis of polymer supported cobalt complexes.
- Sailaja,Radhakrishna Reddy,Mohana Raju,Hussain Reddy
-
p. 156 - 160
(2007/10/03)
-
- Aldimine and Ketimine Derivatives of Titanium(IV)
-
Reactions of titanium isopropoxyde with aldimines and ketamines in equimolar ratios have been carried out.The products have been obtained in almost quantitative yields and characterized on the basis of elemental analyses, molecular weight determinations, exchange reactions, conductance measurements and IR, PMR and UV spectral data.
- Sharma, R. K.,Singh, R. V.,Tandon, J. P.
-
p. 378 - 379
(2007/10/02)
-
