scholarly journals Al(Salen) Metal Complexes in Stereoselective Catalysis

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1716 ◽  
Author(s):  
Andrea Gualandi ◽  
Francesco Calogero ◽  
Simone Potenti ◽  
Pier Giorgio Cozzi

Salen ligands are a class of Schiff bases simply obtained through condensation of two molecules of a hydroxyl-substituted aryl aldehyde with an achiral or chiral diamine. The prototype salen, or N,N′-bis(salicylidene)ethylenediamine has a long history, as it was first reported in 1889, and immediately, some of its metal complexes were also described. Now, the salen ligands are a class of N,N,O,O tetradentate Schiff bases capable of coordinating many metal ions. The geometry and the stereogenic group inserted in the diamine backbone or aryl aldehyde backbone have been utilized in the past to efficiently transmit chiral information in a variety of different reactions. In this review we will summarize the important and recent achievements obtained in stereocontrolled reactions in which Al(salen) metal complexes are employed. Several other reviews devoted to the general applications and synthesis of chromium and other metal salens have already been published.

Author(s):  
Veena R Nair ◽  
Meera Jacob ◽  
Texin Joseph ◽  
Jaya T Varkey

Chitosan, a natural polysaccharides biopolymer is a versatile and promising biomaterial. Chitosan metal complexes stand out in their applicability in different research fields due to their biocompatibility and biodegradability properties. Presence of primary aliphatic amino group along the polymer chain allows for a variety of chemical modifications, of which the most significant is imine functionalization. The ability to easily perform complexation between chitosan Schiff bases and metal ions results in metal complexes, enhancing its application, resulting in further innovation in various fields. The most recent advances of chitosan Schiff base complexes in various fields, including biomedical, catalysis, environmental, and adsorption are summarised in this review.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ezzat Khan ◽  
Muhammad Hanif ◽  
Muhammad Salim Akhtar

Abstract Schiff bases are in the field of medicinal and material chemistry for a long time. There are several advancements from time to time towards facile synthesis and potential applications. As medicines they have been applied as organic molecules as well as their metal complexes. The activities of metal complexes have been found to increase due to increase lipophilicity in comparison to the corresponding free ligand. Besides simple coordination compounds they have been applied as ionic liquid (IL)- supported and IL-tagged species with far enhanced efficiency. Among metal complexes recent advancement deals with photodynamic therapy to treat a number of tumors with fewer side effects. Schiff bases are efficient ligands and their complexes with almost all metal ions are reported. This mini-review article deals with complexes of Schiff bases with biologically compatible metal ions, Co(II), Cu(II), Zn(II), Pd(II), Ag(I), Pt(II) and their potential uses to combat cancerous cells. Strong hopes are associated with photodynamic therapy and IL-tagged and IL-supported Schiff bases and their complexes.


2006 ◽  
Vol 60 (4) ◽  
Author(s):  
H. Mart ◽  
M. Koç ◽  
V. Muradoğlu ◽  
H. Yürük

AbstractThe oligo-ortho-aminophenol was synthesized by the oxidative polycondensation of ortho-aminophenol with air oxygen. The oligophenylazomethinephenol was synthesized by the condensation of aniline with oligosalicylaldehyde. Metal complexes of these oligomers with Cu(II), Co(II), Zn(II), and Ni(II) were synthesized and characterized. Based on the results of thermogravimetric analysis, synthesized oligomer—metal complexes were more stable against heat and thermooxidative decomposition than some polymeric Schiff bases and polymer—metal complexes. Additionally, the presence of metal ions increased the thermal stability of oligo-ortho-aminophenol, while the thermal stability of oligophenylazomethinephenol was lowered.


2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.


Author(s):  
Duraisamy Udhayakumari

In the design of novel fluorescent chemosensors, investigation of new sensing mechanisms between recognition and signal reporting units is of increasing interest. In recent years, a smart chemosensor probe containing a 1,8-naphthalimide moiety could be developed as a fluorescent and colorimetric sensor for toxic anions, metal ions, biomolecules, nitroaromatics, and acids and be further applied to monitor the relevant biological applications. In this field, several problems and challenges still exist. This critical review is mainly focused on various sensing mechanisms that have emerged in the past few years, such as Photo-Induced Electron Transfer (PET), Intramolecular Charge Transfer (ICT), Fluorescence Resonance Energy Transfer (FRET), Excited-State Intramolecular Proton Transfer (ESIPT), hydrogen bonding and displacement approach. The review concludes with some current and future perspectives, including the use of the naphthalimides for sensing anions, metal ions, biomolecules, nitroaromatics and acids and their potential uses in various fields.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1739
Author(s):  
Artyom A. Astafiev ◽  
Olga V. Repina ◽  
Boris S. Tupertsev ◽  
Alexey A. Nazarov ◽  
Maria R. Gonchar ◽  
...  

Arylazoimidazoles are important dyes which were intensively studied in the past. In contrast, triarylazoimidazoles (derivatives which carry aryl substituents at the imidazole core) received almost no attention in the scientific literature. Here, we report a new family of simple and easily accessible triarylazoimidazole-group 12 metal complexes, which feature highly efficient photo-luminescence emission (Φ up to  0.44). Novel compounds exhibit bright red emission in solution, which could be excited with a visible light.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3255
Author(s):  
Denise Bellotti ◽  
Maurizio Remelli

Deferoxamine B is an outstanding molecule which has been widely studied in the past decade for its ability to bind iron and many other metal ions. The versatility of this metal chelator makes it suitable for a number of medicinal and analytical applications, from the well-known iron chelation therapy to the most recent use in sensor devices. The three bidentate hydroxamic functional groups of deferoxamine B are the centerpiece of its metal binding ability, which allows the formation of stable complexes with many transition, lanthanoid and actinoid metal ions. In addition to the ferric ion, in fact, more than 20 different metal complexes of deferoxamine b have been characterized in terms of their chemical speciation in solution. In addition, the availability of a terminal amino group, most often not involved in complexation, opens the way to deferoxamine B modification and functionalization. This review aims to collect and summarize the available data concerning the complex-formation equilibria in solutions of deferoxamine B with different metal ions. A general overview of the progress of its applications over the past decade is also discussed, including the treatment of iron overload-associated diseases, its clinical use against cancer and neurodegenerative disorders and its role as a diagnostic tool.


1999 ◽  
Vol 6 (2) ◽  
pp. 67-73 ◽  
Author(s):  
Claudiu T. Supuran ◽  
Andrea Scozzafava ◽  
Luca Menabuoni ◽  
Francesco Mincione ◽  
Fabrizio Briganti ◽  
...  

Metal complexes of a heterocyclic sulfonamides possessing very strong carbonic anhydrase (CA) inhibitory properties, i.e., 5-(p-fluorobenzenesulfonylamido)-1,3,4-thiadiazole-2-sulfonamide (p-fluorobenzolamide) were prepared. The new complexes contained metal ions such as Zn(II), Cu(II), Co(II), Ni(II), Cd(II) and Mn(II). The new compounds were characterized by standard physico-chemical procedures, and assayed as inhibitors of three CA isozymes, CA I, II and IV. Very good inhibition has been evidenced both for the parent sulfonamides as well as for the prepared complexes, against all three investigated isozymes. Some of these new complexes as well as the parent sulfonamide, strongly lowered intraocular pressure (IOP) in normotensive rabbits when administered as a 2% solution into the eye.


2010 ◽  
Vol 20 (4) ◽  
pp. 493-502 ◽  
Author(s):  
Mohammedshafi A. Phaniband ◽  
Shreedhar D. Dhumwad ◽  
Shashikanth R. Pattan

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