Next Article in Journal / Special Issue
Synthesis and Characterization of Cerium(IV) Metallocenes
Previous Article in Journal / Special Issue
Magnetic and Photo-Physical Properties of Lanthanide Dinuclear Complexes Involving the 4,5-Bis(2-Pyridyl-N-Oxidemethylthio)-4′,5′-Dicarboxylic Acid-Tetrathiafulvalene-, Dimethyl Ester Ligand
Article Menu

Export Article

Open AccessArticle
Inorganics 2015, 3(4), 573-588; doi:10.3390/inorganics3040573

On the Dehydrocoupling of Alkenylacetylenes Mediated by Various Samarocene Complexes: A Charming Story of Metal Cooperativity Revealing a Novel Dual Metal σ-Bond Metathesis Type of Mechanism (DM|σ-BM)

CNRS (Centre National de la Recherche Scientifique) & INSA (Institut National des Sciences Appliquées), UPS (Université Paul Sabatier), LPCNO (Laboratoire de Physique et Chimie des Nano-objets), Université de Toulouse, 135 Avenue de Rangueil, Toulouse F-31077, France
*
Authors to whom correspondence should be addressed.
Academic Editors: Stephen Mansell and Steve Liddle
Received: 30 September 2015 / Revised: 24 November 2015 / Accepted: 26 November 2015 / Published: 4 December 2015
(This article belongs to the Special Issue Rare Earth and Actinide Complexes)
View Full-Text   |   Download PDF [1135 KB, uploaded 4 December 2015]   |  

Abstract

The prevailing reductive chemistry of Sm(II) has been accessed and explored mostly by the use of samarocene precursors. The highly reducing character of these congeners, along with their Lewis acidity and predominantly ionic bonding, allows for the relatively facile activation of C–H bonds, as well as peculiar transformations of unsaturated substrates (e.g., C–C couplings). Among other important C–C coupling reactions, the reaction of phenylacetylene with different mono- or bimetallic samarocene complexes affords trienediyl complexes of the type {[(C5Me5)2Sm]2(µ-η22-PhC4Ph)}. In contrast, when t-butylacetylene is used, uncoupled monomers of the type (C5Me5)2Sm(C≡C–tBu) were obtained. Although this type of reactivity may appear to be simple, the mechanism underlying these transformations is complex. This conclusion is drawn from the density functional theory (DFT) mechanistic studies presented herein. The operating mechanistic paths consist of: (i) the oxidation of each samarium center and the concomitant double reduction of the alkyne to afford a binuclear intermediate; (ii) the C–H scission of the acetylinic bond that lies in between the two metals; (iii) a dual metal σ-bond metathesis (DM|σ-SBM) process that releases H2; and eventually (iv) the C–C coupling of the two bridged μ-alkynides to give the final bimetallic trienediyl complexes. For the latter mechanistic route, the experimentally used phenylacetylene was considered first as well as the aliphatic hex-1-yne. More interestingly, we shed light into the formation of the mono(alkynide) complex, being the final experimental product of the reaction with t-butylacetylene. View Full-Text
Keywords: samarium; σ-bond metathesis; trienediyl; C–C coupling; mechanism; DFT calculations; bimetallic complexes; terminal alkynes samarium; σ-bond metathesis; trienediyl; C–C coupling; mechanism; DFT calculations; bimetallic complexes; terminal alkynes
Figures

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Kefalidis, C.E.; Maron, L. On the Dehydrocoupling of Alkenylacetylenes Mediated by Various Samarocene Complexes: A Charming Story of Metal Cooperativity Revealing a Novel Dual Metal σ-Bond Metathesis Type of Mechanism (DM|σ-BM). Inorganics 2015, 3, 573-588.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Inorganics EISSN 2304-6740 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top