molecules-logo

Journal Browser

Journal Browser

Special Issue "Schiff Base and Its Metal Complexes"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Inorganic Chemistry".

Deadline for manuscript submissions: closed (31 May 2019).

Special Issue Editor

Prof. Antonella Dalla Cort
E-Mail Website
Guest Editor
Dipartimento di Chimica and IMC-CNR, Università la Sapienza, 00185 Roma, Italy
Interests: supramolecular chemistry; metal salophen/salen complexes; molecular recognition; weak interactions; uranyl and zinc-Schiff base complexes

Special Issue Information

Dear Colleagues,

Schiff bases are one of the most popular and old ligands in coordination chemistry. Known since 1864 when, for the first time, Ugo Schiff reported on products deriving from the condensation of ketones or aldehydes with primary amines, such derivatives have been extensively used for countless applications. Their easy synthesis allows for finetuning of their stereo-electronic features, and their ability to form stable complexes with most transition metals easily provides access to a large variety of derivatives with remarkable biological and catalytic activities, electroluminescent, fluorescence and nonlinear properties that can be used in many research fields for exciting applications.

For this Special Issue of Molecules, I would like to kindly invite worldwide colleagues working in this research area to submit original research articles and reviews on all the aspects of the chemistry of these ligands and of their metal complexes.

Prof. Antonella Dalla Cort
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Schiff base ligands
  • Schiff base metal complexes
  • salen and salophen ligands
  • metal complexes

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle
New Artificial Biomimetic Enzyme Analogues Based on Iron(II/III) Schiff Base Complexes: An Effect of (Benz)imidazole Organic Moieties on Phenoxazinone Synthase and DNA Recognition
Molecules 2019, 24(17), 3173; https://doi.org/10.3390/molecules24173173 - 31 Aug 2019
Abstract
Elucidation of the structure and function of biomolecules provides us knowledge that can be transferred into the generation of new materials and eventually applications in e.g., catalysis or bioassays. The main problems, however, concern the complexity of the natural systems and their limited [...] Read more.
Elucidation of the structure and function of biomolecules provides us knowledge that can be transferred into the generation of new materials and eventually applications in e.g., catalysis or bioassays. The main problems, however, concern the complexity of the natural systems and their limited availability, which necessitates utilization of simple biomimetic analogues that are, to a certain degree, similar in terms of structure and thus behaviour. We have, therefore, devised a small library of six tridentate N-heterocyclic coordinating agents (L1L6), which, upon complexation, form two groups of artificial, monometallic non-heme iron species. Utilization of iron(III) chloride leads to the formation of the 1:1 (Fe:Ln) ‘open’ complexes, whereas iron(II) trifluoromethanosulfonate allows for the synthesis of 1:2 (M:Ln) ‘closed’ systems. The structural differences between the individual complexes are a result of the information encoded within the metallic centre and the chosen counterion, whereas the organic scaffold influences the observed properties. Indeed, the number and nature of the external hydrogen bond donors coming from the presence of (benz)imidazole moieties in the ligand framework are responsible for the observed biological behaviour in terms of mimicking phenoxazinone synthase activity and interaction with DNA. Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Open AccessArticle
A Simple and Efficient Mechanochemical Route for the Synthesis of Salophen Ligands and of the Corresponding Zn, Ni, and Pd Complexes
Molecules 2019, 24(12), 2314; https://doi.org/10.3390/molecules24122314 - 22 Jun 2019
Abstract
A number of salophen ligands and their Zn, Ni, and Pd complexes were synthesized by an efficient one-pot mechanosynthesis protocol. The reaction products were characterized by means of complementary solid-state techniques, i.e., powder X-ray diffraction, single-crystal X-ray diffraction, and solid-state NMR spectroscopy. Four [...] Read more.
A number of salophen ligands and their Zn, Ni, and Pd complexes were synthesized by an efficient one-pot mechanosynthesis protocol. The reaction products were characterized by means of complementary solid-state techniques, i.e., powder X-ray diffraction, single-crystal X-ray diffraction, and solid-state NMR spectroscopy. Four new crystal structures of metal salophen complexes as DMSO solvates are here reported. The described simple and relatively fast (about 1 h for all derivatives) procedure is a good alternative to classical methods performed in organic solvents. Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Open AccessArticle
Supramolecular Detection of a Nerve Agent Simulant by Fluorescent Zn–Salen Oligomer Receptors
Molecules 2019, 24(11), 2160; https://doi.org/10.3390/molecules24112160 - 08 Jun 2019
Abstract
We report on new Zn–Salen oligomer receptors able to recognize a nerve agent simulant, namely dimethyl methylphosphonate (DMMP), by a supramolecular approach. In particular, three Zn-Salen oligomers (Zn–Oligo–A, –B, and –C), differing by the length distribution, were obtained and characterized by NMR, Gel [...] Read more.
We report on new Zn–Salen oligomer receptors able to recognize a nerve agent simulant, namely dimethyl methylphosphonate (DMMP), by a supramolecular approach. In particular, three Zn-Salen oligomers (Zn–Oligo–A, –B, and –C), differing by the length distribution, were obtained and characterized by NMR, Gel Permeation Chromatography (GPC), UV-Vis, and fluorescence spectroscopy. Furthermore, we investigated their recognition properties towards DMMP by using fluorescence measurements. We found that the recognition ability depends on the length of the oligomeric chain, and the Zn–Oligo–C shows a binding constant value higher than those already reported in literature for the DMMP detection. Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Open AccessArticle
Dioxygen Activation with Molybdenum Complexes Bearing Amide-Functionalized Iminophenolate Ligands
Molecules 2019, 24(9), 1814; https://doi.org/10.3390/molecules24091814 - 10 May 2019
Abstract
Two novel iminophenolate ligands with amidopropyl side chains (HL2 and HL3) on the imine functionality have been synthesized in order to prepare dioxidomolybdenum(VI) complexes of the general structure [MoO2L2] featuring pendant internal hydrogen bond donors. For reasons [...] Read more.
Two novel iminophenolate ligands with amidopropyl side chains (HL2 and HL3) on the imine functionality have been synthesized in order to prepare dioxidomolybdenum(VI) complexes of the general structure [MoO2L2] featuring pendant internal hydrogen bond donors. For reasons of comparison, a previously published complex featuring n-butyl side chains (L1) was included in the investigation. Three complexes (13) obtained using these ligands (HL1HL3) were able to activate dioxygen in an in situ approach: The intermediate molybdenum(IV) species [MoO(PMe3)L2] is first generated by treatment with an excess of PMe3. Subsequent reaction with dioxygen leads to oxido peroxido complexes of the structure [MoO(O2)L2]. For the complex employing the ligand with the n-butyl side chain, the isolation of the oxidomolybdenum(IV) phosphino complex [MoO(PMe3)(L1)2] (4) was successful, whereas the respective Mo(IV) species employing the ligands with the amidopropyl side chains were found to be not stable enough to be isolated. The three oxido peroxido complexes of the structure [MoO(O2)L2] (911) were systematically compared to assess the influence of internal hydrogen bonds on the geometry as well as the catalytic activity in aerobic oxidation. All complexes were characterized by spectroscopic means. Furthermore, molecular structures were determined by single-crystal X-ray diffraction analyses of HL3, 13, 911 together with three polynuclear products {[MoO(L2)2]2(µ-O)} (7), {[MoO(L2)]4(µ-O)6} (8) and [C9H13N2O]4[Mo8O26]·6OPMe3 (12) which were obtained during the synthesis of reduced complexes of the type [MoO(PMe3)L2] (46). Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Review

Jump to: Research

Open AccessReview
On the Aggregation and Sensing Properties of Zinc(II) Schiff-Base Complexes of Salen-Type Ligands
Molecules 2019, 24(13), 2514; https://doi.org/10.3390/molecules24132514 - 09 Jul 2019
Abstract
The zinc(II) ion forms stable complexes with a wide variety of ligands, but those related to Schiff-bases are among the most largely investigated. This review deals with the peculiar aggregation characteristics of Zn(II) Schiff-base complexes from tetradentate N2O2 salen-type ligands, [...] Read more.
The zinc(II) ion forms stable complexes with a wide variety of ligands, but those related to Schiff-bases are among the most largely investigated. This review deals with the peculiar aggregation characteristics of Zn(II) Schiff-base complexes from tetradentate N2O2 salen-type ligands, L, derivatives from salicylaldehydes and 1,2-diamines, and is mostly focused on their spectroscopic properties in solution. Thanks to their Lewis acidic character, ZnL complexes show interesting structural, nanostructural, and aggregation/deaggregation properties in relation to the absence/presence of a Lewis base. Deaggregation of these complexes is accompanied by relevant changes of their spectroscopic properties that can appropriately be exploited for sensing Lewis bases. Thus, ZnL complexes have been investigated as chromogenic and fluorogenic chemosensors of charged and neutral Lewis bases, including cell imaging, and have shown to be selective and sensitive to the Lewis basicity of the involved species. From these studies emerges that these popular, Lewis acidic bis(salicylaldiminato)Zn(II) Schiff-base complexes represent classical coordination compounds for modern applications. Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Open AccessFeature PaperReview
Al(Salen) Metal Complexes in Stereoselective Catalysis
Molecules 2019, 24(9), 1716; https://doi.org/10.3390/molecules24091716 - 02 May 2019
Cited by 1
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Schiff Base and Its Metal Complexes)
Show Figures

Graphical abstract

Back to TopTop