Research projects at Lisbon
Organometallic and Coordination Chemistry at Metal Centres with Biological Significance
Positions for ESR grants
are immediately available for 6 – 12 months, subject to renewal, and are
expected to allow the candidate to continue for D.Phil. studies under a
subsequent national fellowship.
The mode of action of
nitrogenases, the nitrogen fixation enzymes, towards the activation of their
substrates still constitutes an intriguing matter, in spite of some noteworthy
achievements like the establishment of the molecular structure of the cofactor
and the stepwise protic reduction of N2 to ammonia at a suitable
transition metal centre in non-aqueous medium.
Our Group has been
engaged on the activation, by coordination to dinitrogen-binding metal centres,
of a variety of small molecules of biological significance, including
alternative nitrogenase substrates like isocyanides, nitriles, cyanide,
cyanamide, alkynes and azide. In particular by ligating an electron-rich metal
centre, with a high pi-electron-releasing ability, those substrates undergo
ready protonation to afford multiple metal-carbon and metal-nitrogen bonded
products which can be postulated as intermediates in the enzymatic reductions.
In the current project we plan to extend some of that chemistry, aiming to mimic the biological function of nitrogenase and other enzymes like nitrile hydratase (hydrolysis of nitriles to carboxamides and other products) and methane monoxygenases (partial oxidation of alkanes, including methane, to products with commercial added value).
The project entails a
preparative stage, with the synthesis of appropriate complexes, namely with
some of those substrates or appropriate reagents, followed by the investigation
of their reactivity towards conversion into the enzymatic products.
Electrochemical methods
will also be applied to study the electronic properties of the metal centres
and ligands and to activate them by electron-transfer towards further chemical
reactions.
Requirements: Highly motivated candidate for D.
Phil. degree with a good mark in the licentiate or M.Sc. course (application to
a D. Phil. fellowship, under a national programme, to further the Network
position, is expected after the researcher gets the required experience); basic
knowledge in coordination and organometallic chemistry; basic experience on the
synthesis and handling of air-sensitive compounds is advisable.
1-
V. Yu. Kukushkin and A.J.L.Pombeiro,
“Additions to Metal-Activated Organonitriles”, Chem. Rev., 2002, 102,
1771-1802.
2-
S.M.P.R. Cunha, M.F.C. Guedes da Silva and A.J.L. Pombeiro, “Mixed
Dinitrogen- Organocyanamide
Complexes of Molybdenum(0) and Their Protic Conversion into Hydrazine and
Amidoazavinylidene Derivatives”, Inorg. Chem., 2003, 42, 2157-2164.
4-
P.M. Reis, J.A.L. Silva, A.F. Palavra, J.J.R. Fraústo da Silva, T.
Kitamura, Y. Fujiwara and A.J.L. Pombeiro, “Single-pot Conversion of Methane
into Acetic Acid, in the Absence of CO and with Vanadium Catalysts Such as
Amavadine”, Angew. Chem., Intern.
Ed.: 2003, 42, 821-823.
5- P.M. Reis, J.A.L. Silva, A.F. Palavra, J.J.R. Fraústo da Silva and
A.J.L. Pombeiro, “Vanadium-Catalyzed Carboxylation of Linear and Cyclic C5
and C6 Alkanes”, J. Catal., 2005, 235, 333-340.
6- Q.
Li, M.F.C. Guedes da Silva and A.J.L. Pombeiro, “Diorganotin(IV) Derivatives
of Substituted Benzohydroxamic Acids
with High Antitumor Acticvity”, Chem. Eur. J., 2004, 10,
1456-1462.
7- A.J.L. Pombeiro, “Comparative Behaviours of
Phospha-alkynes and Alkynes at Electron- rich Phosphinic Metal Centres”, J. Organometal. Chem., 2001, 632, 215-226.
8- A.J.L. Pombeiro, M.F.C. Guedes da
Silva and R.A. Michelin, “Aminocarbyne Complexes Derived from Isocyanides
Activated Toward Electrophilic Addition”,
Coord. Chem. Rev., 2001, 218,
43-74.
Cost of living in
Lisbon: Accommodation:
from ca. 220 euros/month (single room in a shared flat or family); other
living expenses: ca. 300 euros/month.
Centro de Química Estrutural
Complexo I, Instituto Superior Técnico
Av. Rovisco Pais, 1049-001 Lisboa, Portugal
FAX: +351.218464455
Phone: +351.218419237
http://dequim.ist.utl.pt/english/
http://myprofile.cos.com/pombeiro