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Phosphametallocenes

Contact : D. Carmichael

Phosphorus derivatives of porphyrinoids.

A second program that targets phosphorus derivatives of porphyrinoids is also based upon "in- house"- [1][2] chemistry that has been developed for the functionalisation of phosphametallocenes. This program has allowed us to target tri- and tetraphosphorus- containing analogues of xanthoporphynogens 3[3] and 4, that show extended delocalization. this has been achieved through a modular synthesis that is described here

                                                                            

Synthesis along with B3LYP/6-31++G(d,p)//marij-BP86/def2-SVP NBO charges and NICS(0) values for tetraphosphaporphyrinogen dianion macrocycle A, bis(diacyl)phospholide [2,5-(CHO)2PC4H2]-B and parent phospholide C,  taken from[3]

The coordination chemistry of the dianions 3 and the neutral ligands 4 towards a range of metals is currently under study. P-C bonds are ca 25% longer than N-C,[4] so the cavity in such phosphaporphyrinoid ligands should be quite small [5] but this is compensated by an innate tendency of the ligand to coordinate metals out of the macrocycle median plane, as exemplified in the zinc complex shown below. Combined experimental and DFT analyses of this complex have been completed.

                                                                                                      

 

X ray structures showing the complexation of a phosphapropyrinogen dianion to zinc. Note the very similar configurations of the macrocycle in the starting dianion (top) and the product (bottom).

 

Phosphorus centres that respond to external stimulate: redox- switchable properties.

The first examples of phosphametallocene complexes contaning ruthenium,[6] cobalt,[7][8] rhodium, [7] iridium,[7] and nickel[9] were all prepared in the laboratory. Extensive studies of these compounds have shown that the presence of the phosphorus atom causes only a relatively minor electronic perturbation In monophospholyl substituted ligands, and that the phosphametallocene products show recognisable 'metallocene- type' character, both with respect to magnetic and redox properties.[10]

                                                                                            

Such phosphametallocenes provide a framework in which the phosphorus atom can undergo unusual redox chemistry. More classical phosphine ligands whose behaviour can be switched quite emphatically through redox chemistry have also been studied within a consortium led by Dr Feréderic Paul the Université de Rennes 1.[10a] in these ligands, a chemically reversible oxidation of the redox sensitive organoiron end group leads to a dimerisation process that has the effect of eliminating the phosphorus lone pair. The coordination chemistry of these redox- switchable ligands has also been studied.[11]

 

                                                                                            

Sustainability in Phosphorus Chemistry :

 

 

 

 

 

 

 

[1]        D. Carmichael, X. F. Le Goff, E. Muller, New J. Chem. 2010, 34, 1341-1347. Link

[2]        D. Carmichael, X.-F. le Goff, E. Muller, European Journal of Inorganic Chemistry 2014, 2014, 1610-1614. Link

[3]          D. Carmichael, A. Escalle-Lewis, G. Frison, X. Le Goff, E. Muller, Chem. Commun. 201248, 302-304. Link

[4]        L. Margules, J. Demaison, P. B. Sreeja, J. C. Guillemin, Journal of Molecular Spectroscopy 2006, 238, 234-240. Link

[5]        D. Delaere, M. T. Nguyen, Chemical Physics Letters 2003, 376, 329-337. Link

[6]        D. Carmichael, L. Ricard, F. Mathey, Journal of the Chemical Society-Chemical Communications 1994, 1167-1168. Link

[7]        K. Forissier, L. Ricard, D. Carmichael, F. Mathey, Organometallics 2000, 19, 954-956. Link

[8]          C. Burney, D. Carmichael, K. Forissier, J. C. Green, F. Mathey, L. Ricard, Chemistry-a European Journal 20039, 2567-2573. Link

[9]          C. Burney, D. Carmichael, K. Forissier, J. C. Green, F. Mathey, L. Ricard, Chemistry-a European Journal  200511, 5381-5390. Link

[10]        a): A. Tohme, G. Grelaud, G. Argouarch, T. Roisnel, S. Labouille, D. Carmichael, F. Paul,             Angewandte Chemie-International Edition 2013, 52, 4445-4448; Link

b): D. Carmichael, F. Mathey, Topics in Current Chemistry 2002, 220, 27-51. Link

[11]        A. Tohme, S. Labouille, T. Roisnel, V. Dorcet, D. Carmichael, F. Paul, Dalton Transactions 2014, 43, 7002-7005. Link