Square-planar metal(II) complexes containing ester functionalised bis(phosphino) amines: Mild P-N methanolysis and C-arene-H cyclometallation
Abstract
The synthesis of three new ester functionalised bis(phosphino)amines Ph2PN{R}PPh2 [R = C6H4(3-CO2Me) 1a; C6H3(3,5-CO2Me)(2) 1b; C6H4(4-CO2Me) 1c] upon stoichiometric reaction of Ph2PCl and the appropriate H2N{R} in Et2O is described. Reaction of 1 equiv. of 1a c with MCl2(cod) (M = Pt, Pd) in CH2Cl2 afforded the dichlorometal(II) complexes PtCl2(1a) 2a, PtCl2(1b) 2b, PtCl2(1c) 2c and PdCl2(1b) 2'b respectively. The corresponding dibromo (and diiodo) platinum(II) complexes 3b (and 4b) were synthesised, in > 80% isolated yields, from PtBr2(cod) or PtI2(cod). When a suspension of 2b in MeOH was stirred at r.t. for ca. 16 h the mixed complex cis-PtCl2[Ph2PNH{R}](Ph2POMe) 5a [R = C6H3(3,5-CO2Me)(2)] was cleanly generated. Metathesis of 5a using excess NaBr or NaI in MeOH/acetone afforded cisPtBr(2)[Ph2PNH{R}](Ph2POMe) 5b or cis-PtI2[Ph2PNH{R}](Ph2POMe) 5c. Methanolysis of PtCl2(1a) 2a at ambient temperature afforded, in low yield (18%), the regiospecific P, C-orthometallated complex cis-PtCl [Ph2PNH{C6H3(3-CO2Me)}](Ph2POMe) 6. We speculate the C - H activated complex 6 is obtained via initial formation of cis-PtCl2[Ph2PNH{C6H4(3-CO2Me)}](Ph2POMe) 7. A similar observation was also found using 2c whereupon examination of the isolated solid, by P-31{H-1} NMR spectroscopy, revealed formation of three complexes namely orthometallated cis-PtCl[Ph2PNH{C6H3(4-CO2Me)}](Ph2POMe) 9, cis-PtCl[Ph2PNH{C6H4(4-CO2Me)}](Ph2POMe) 10 and cis-PtCl2(Ph2POMe)(2) 8. All new compounds reported here have been characterised by multinuclear NMR and IR spectroscopy, microanalysis and in six cases by single crystal X-ray crystallography. The X-ray structure of cis-PtCl[Ph2PNH{C6H3(3-CO2Me)}]( Ph2POMe) 6 revealed selective C - H cycloplatination at the 6-position (as opposed to the 2-position) of the N-arene ring.
Citation
Gaw , K G , Smith , M B , Wright , J B , Slawin , A M Z , Coles , S J , Hursthouse , M B & Tizzard , G J 2012 , ' Square-planar metal(II) complexes containing ester functionalised bis(phosphino) amines: Mild P-N methanolysis and C-arene-H cyclometallation ' , Journal of Organometallic Chemistry , vol. 699 , pp. 39-47 . https://doi.org/10.1016/j.jorganchem.2011.11.003
Publication
Journal of Organometallic Chemistry
Status
Peer reviewed
ISSN
0022-328XType
Journal article
Rights
© The Authors. This is an open access article, available from http://www.sciencedirect.com
Description
Funding: EPSRC studentship and Infinium UK LtdCollections
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Related items
Showing items related by title, author, creator and subject.
-
Hydrothermal alteration and mineralisation of the Nigerian anorogenic ring complexes: with special reference to the Saiya Shokobo complex
Kinnaird, Judith Ann (University of St Andrews, 1987) - ThesisThe Nigerian anorogenic province is characterised by more than 50 complexes. In some complexes, the outer limits of the complexes are defined partly or completely by a ring dyke. This intrusion, generally composed of granite ... -
Cetaceans have complex brains for complex cognition
Marino, Lori; Connor, Richard C.; Fordyce, R. Ewan; Herman, Louis M.; Hof, Patrick R.; Lefebvre, Louis; Lusseau, David; McCowan, Brenda; Nimchinsky, Esther A.; Pack, Adam A.; Rendell, Luke; Reidenberg, Joy S.; Reiss, Diana; Uhen, Mark D.; Van der Gucht, Estel; Whitehead, Hal (2007-05) - Journal articleThe brain of a sperm whale is about 60% larger in absolute mass than that of an elephant. Furthermore, the brains of toothed whales and dolphins are significantly larger than those of any nonhuman primates and are second ... -
Versatile para-substituted pyridine lanthanide coordination complexes allow late stage tailoring of complex function
Starck, Matthieu; Fradgley, Jack; De Rosa, Davide F; Batsanov, Andrei; Papa, Maria; Taylor, Michael; Lovett, Janet; Lutter, Jacob; Allen, Matthew; Parker, David (2021-11-16) - Journal articleA series of cationic and neutral p-Br and p-NO2 pyridine substituted Eu(III) and Gd(III) coordination complexes serve as versatile synthetic intermediates. Nucleophilic aromatic substitution occurs readily at the para ...