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 . DOI: 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.
-
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 ... -
Ultrafast photophysics of iridium complexes
Hedley, Gordon J. (University of St Andrews, 2010-11-30) - ThesisThis thesis presents ultrafast photophysical measurements on a number of phosphorescent iridium complexes and establishes relationships between the relaxation rates and the vibrational properties of the material. When ... -
The wall painting of the Chapel-martyrium Motsameta in the rock–cut monastery complex of Udabno David–Gareji.
Khoshtaria, Tinatin. (School of Art History, University of St Andrews, 2004) - Journal articleAmong the numerous churches of the monasteries of Gareji, there is situated at the top of a mountain in west of the mine complex, the little church of the Forty Martyrs, or Motsameta. The paintings of this chapel-martyrium, ...