Jump to main content
Jump to site search

Issue 12, 2012
Previous Article Next Article

Novel access to carbodiphosphoranes in the coordination sphere of group 10 metals: template synthesis and protonation of PCP pincer carbodiphosphorane complexes of C(dppm)2

Author affiliations

Abstract

In a novel template synthesis of carbodiphosphoranes (CDPs), the phosphine functionalized CDP ligand C(dppm)2 (dppm = Ph2PCH2PPh2) is formed in the coordination sphere of group 10 metals from CS2 and 4 equivalents of dppm. The products are the PCP pincer complexes [M(Cl)(C(dppm)2-κ3P,C,P)]Cl (M = Ni, Pd, Pt) and 2 equivalents of dppmS. The compound C(dppm)2, which is composed of a divalent carbon atom and two dppm subunits, represents a new PCP-type pincer ligand with the formally neutral carbon Lewis base of the CDP functionality as the central carbon. Treatment of [M(Cl)(C(dppm)2-κ3P,C,P)]Cl (M = Pd, Pt) with hydrochloric acid results in protonation at the CDP carbon atom and the formation of the PCP pincer complexes [M(Cl)(CH(dppm)2-κ3P,C,P)]Cl2 (M = Pd, Pt). The PCP pincer ligand [CH(dppm)2]+ involves a formally cationic central carbon donor. The reaction of [Ni(Cl)(C(dppm)2-κ3P,C,P)]Cl with HCl leads to the extrusion of NiCl2 and formation of the diprotonated CDP compound [CH2(dppm)2]Cl2, from which the monoprotonated conjugate base [CH(dppm)2]Cl is obtained upon addition of bases, such as NH3. The crystal structures of [M(Cl)(C(dppm)2-κ3P,C,P)]Cl (M = Ni, Pd, Pt), [Ni(Cl)(C(dppm)2-κ3P,C,P)]2[NiCl4], [M(Cl)(CH(dppm)2-κ3P,C,P)]Cl2 (M = Pd, Pt) as well as [CH2(dppm)2]Cl2 and [CH(dppm)2]Cl are presented. A comparison of the solid state structures reveals interesting features, e.g. infinite supramolecular networks mediated by C–H⋯Cl hydrogen bond interactions and an unexpected loss of molecular symmetry upon protonation in the complexes [M(CH(dppm)2-κ3P,C,P)(Cl)]Cl2 (M = Pd, Pt) as a result of the flexible ligand backbone. Additionally the new compounds were characterized comprehensively in solution by multinuclear 31P, 13C and 1H NMR spectroscopy: Several spectroscopic parameters show a striking variability in particular regarding the carbodiphosphorane functionality. Furthermore the compound [Ni(Cl)(C(dppm)2-κ3P,C,P)]Cl was examined by cyclic voltammetry (CV) and could be shown to display quasi-reversible oxidative as well as reductive behaviour.

Graphical abstract: Novel access to carbodiphosphoranes in the coordination sphere of group 10 metals: template synthesis and protonation of PCP pincer carbodiphosphorane complexes of C(dppm)2

Back to tab navigation

Supplementary files

Publication details

The article was received on 16 Oct 2011, accepted on 06 Dec 2011 and first published on 09 Feb 2012


Article type: Paper
DOI: 10.1039/C2DT11949H
Dalton Trans., 2012,41, 3503-3514

  •   Request permissions

    Novel access to carbodiphosphoranes in the coordination sphere of group 10 metals: template synthesis and protonation of PCP pincer carbodiphosphorane complexes of C(dppm)2

    C. Reitsamer, S. Stallinger, W. Schuh, H. Kopacka, K. Wurst, D. Obendorf and P. Peringer, Dalton Trans., 2012, 41, 3503
    DOI: 10.1039/C2DT11949H

Search articles by author

Spotlight

Advertisements