THE CHEMISTRY OF
LOW COORDINATED P-BLOCK ELEMENTS
Stable metallylene species. From design to applications
PCMetallylene PN-III-P4-ID-PCE-2016-0351
SUMMARY
The chemistry of metallylenes, heavier analogues of carbenes, has received an increased interest over the last decades, especially since the new advances in organometallic chemistry allowed the synthesis and stabilization of what were previously considered „exotic” species, like silylenes, germylenes and even stannylenes. This type of compounds are important species both for the fundamental knowledge in the organometallic chemistry of p-block elements but also for their possible use, especially in activation of small molecules as well as for the design of novel semiconductors and transition metal complexes. The main objective of the project consists in the design and synthesis of new heavier analogues of carbenes, stabilized either by using pincer-type ligands based on sulfur, phosphorus or mixture of both, or by introduction of the :E(II) (E = Si, Ge, Sn) in an aromatic or pseudo-aromatic cycle. Our previous results in germylene and stannylene chemistry encourage our plan to extend this research. Not only the sulfonyl, but also the sulfinyl or mixed sulfonyl - sulfinyl moieties will be used, as well as newly designed phosphorus based pincer ligands with donor groups as phosphavinylideneoxophosphorane and evaluate their influence on the stability of metallylenes. The coordination ability will be assessed by bonding of the newly designed metallylenes to transition metal fragments. The bonding modes to various Lewis acids will also be investigated. All the designed compounds will be completely characterized not only by the usual physicochemical methods, but also a complex computational study in order to determine the role and the relevance of all factors involved in the stabilization of the new low-valent systems. Given our experience in this field and the promising results obtained so far, we are convinced that we can lead to successful completion of this project obtaining in the end, the desired results.
OBJECTIVES
Objective O1: Design and synthesis of new heavier analogues of carbenes, stabilized by i) intramolecular coordination using new pincer-type ligands or by ii) placing the >E(II) species (E = Si, Ge, Sn) into an aromatic or pseudo-aromatic cycle.
Objective O2: The design and synthesis of new coordinative compounds. Due to the multiple possibilities of coordination of the metallylene derivatives towards organometallic MLn fragments, a rich versatility of these kind of compounds is expected. This will permit to develop several new families of low-coordinative compounds, in order to study in detail the fundamental aspects regarding structural proprieties, reactivity and also to evaluate some applicative aspects of these compounds. The new systems thus obtained would be stable at room temperature and will be tested in order to determine a possible biological or catalytic activity.
Objective O3: The complete characterization of all the obtained species by specific physicochemical, structural (mass spectrometry, multinuclear NMR, elemental analysis and X-ray structure analysis) and computational methods (DFT calculations, NBO and MO analysis.
The expected deliverables, correlated with the specific objectives and activities are:
3 research reports (one in each year of the project)
10 scientific articles (minimum) published in journals with impact factor, of which at least 6 scientific articles published in top 50%, (Q1+Q2), according to the scores of influence (AIS).
6 attendances to conferences (minimum)
4 short research stages in prestigious laboratories in the field
1 final scientific report
2017 stage
Activities 2017:
A.1.1. Design and synthesis of new pincer and aromatic or pseudoaromatic ligands.
A.1.2. Purification and charaterisation of the new pincer and aromatic or pseudoaromatic ligands.
A.1.3. Research project management.
A.1.4. Dissemination of the research results.
Estimated results for the 2017 stage: 2 scientific articles having an impact factor (of which minimum 1 in the Q1+Q2); 1 attendance to a conference (minimum); 1 research stay (minimum); 1 scientific report.
The obtained results lead to the publication of 3 scientific articles, the attendence to an international conference (workshop) and 2 research stages on the topic of the project.
2018 stage
Synthesis, characterization and reactivity study of the newly obtained metallylenes and their compounds with transition metals or other type of Lewis acids.
Activities 2018:
A.2.2. The design and synthesis of metallylene species containing the obtained ligands
A.2.3. The purification and characterization of the new metallylenes.
A.2.4. Reactivity study of newly metallylenes obtained through coordination to transition metals or addition of other species having Lewis acid character.
A.2.5. Research project management.
A.2.6. Dissemination of the research results.
Estimated results for the 2018 stage: (minimum) 4 scientific articles having an impact factor (of which minimum 3 in the Q1+Q2); 3 attendances to conferences (minimum); 2 research stays (minimum); 1 scientific report.
2019 stage
Stability studies of metallylenes and the complex species including metallylenes and the preliminary study regarding their catalytic and biological activity.
Activities 2019:
A3.1. The purification and phisico-chemical and structural characterization of the metallylenes and the metallylene containing complex species.
A.3.2. Preliminary studies regarding the catalytic and biological activity of the new metallylenes and metallylene containing complex species obtained through their coordination to transition metals.
A.3.3. Research project management.
A.3.4. Dissemination of the research results.
Estimated results for the 2019 stage: (minimum) 4 scientific articles having an impact factor (of which minimum 3 in the Q1+Q2), 3 attendances to conferences (minimum), 1 research stay (minimum); 1 scientific report, 1 final report
.