Profesores

Baraldo, Luis M
Assistant professor UBA

CONICET: Assistant Investigator
INQUIMAE

Inorganic, Analytical and Physical Chemistry Department. 
Tel. 54-11- 4576-3378/80 ext. 127 
Fax: 54-11- 4576-3341 

Msc. in Chemistry Univ. of Buenos Aires, 1988. 
PhD. in Chemistry Univ. of Buenos Aires, 1994. 
Postdoctoral researcher, Department of Chemistry
University of North Carolina, 1995-1997.
Postdoc. researcher, Department of Chemistry
Massachusetts Institute of Technology 1997-1998.

e-mail: baraldo@qi.fcen.uba.ar 

Field of Interest:
Synthesis of cyano bridged complexes. Coupling between metals. Donor acceptor-interaction. Mixed valence complexes. 

"Synthesis and characterization of metal arrays coupled through bridges with defined geometry."

Objective
The areas of interest of our research are: i) exploring the synthesis of mononulear complexes that may be precursors for cyano bridged compounds, ii) synthesis, isolation and characterization of linear cyano bridged multi metallic arrays, iii) modeling the properties of these arrays iv) use of these arrays as building blocks for the construction of molecular materials.

Methods

Our general strategy is to use coordination compounds containing voluminous ligands that will force trans geometry around each metal in the array promoting the formation of linear chains. These ligands also are useful for tuning the electronic properties of the array, to tailor their solubility properties or to promote interaction between the chains. These compounds typically are obtained in multigram quantities as colored crystalline solids that dissolve readily in chlorinated solvents, and they typically maintain their integrity when kept at a temperature less than or equal to ca. 30 ºC.

A variety of spectroscopic techniques are used to optimize synthetic conditions and to characterize new compounds. These include UV-vis, FTIR, electrochemistry, spectrolectrochemistry, NMR, Mossbauer, SQUID, and single-crystal X-ray experiments.

Significance

There is an enormous interest in the study of macromolecules of nanoscopic dimensions. These efforts are fueled by the perspective of designing materials with structural features of nanometer size (1 nm to 1 μm). In this regard, the coupling of metals with suitable bridges like the cyano group offers the opportunity to combine a defined geometry with interesting electronic, optical or magnetical properties. Within this features linear assemblies are of particular interest for design of molecular devices such as molecular wires or transistors. This configuration also allows for the maximum charge separation required for light harvesting devices and they are also ideal systems to study long-range processes over extended distances.

The ability of cyanide to bridge between metals has been successfully employed to produce molecular materials with interesting properties, but most of this materials lack manageable properties processing properties being insoluble and d infusible. On the other hand, soluble compounds are amenable of a complete characterization in solution and may be used in the synthesis of molecular materials with predefined properties. The study of these systems will improve our understanding of the coupling between metals and properties of extended materials including this feature.

Funding:

Fundación Antorchas,  ANPCyT

Selected Publications:

"Metallonitrosyl Fragment as Electron Acceptor: Intramolecular Charge Transfer, Long Range Electronic Coupling, and Electrophilic Reactivity in the trans-[NCRu(py)4(CN)Ru(py)4NO]3+ Ion" Roncaroli F; Baraldo LM; Slep LD; Olabe JA; web published in Inorg. Chem.

"Kinetics and mechanism of ligand interchange in pentacyano-L-osmate(II) complexes (L = H2O, NH3, N-heterocyclic ligands)", Slep LD; Albores P; Baraldo LM; Olabe JA; Inorg. Chem., 2002, Vol 41, Iss 1, pp 114-120.

"Advances in the coordination chemistry of [M(CN)(5)L](n-) ions (M = Fe, Ru, Os)", Baraldo LM; Forlano P; Parise AR; Slep LD; Olabe JA, Coor. Chem. Rev.  2001, Vol 219, pp 881-921.

"On the origin of selective nitrous oxide N-N bond cleavage by three-coordinate molybdenum(III) complexes", Cherry JPF; Johnson AR; Baraldo LM; Tsai YC; Cummins CC; Kryatov SV; Rybak-Akimova EV; Capps KB; Hoff CD; Haar CM; Nolan SP; J. of the Am. Chem. Soc.  2001, Vol 123, Iss 30, pp 7271-7286.

"Redox-catalyzed binding of dinitrogen by molybdenum N-tert-hydrocarbylanilide complexes: Implications for dinitrogen functionalization and reductive cleavage", Peters JC; Cherry JPF; Thomas JC; Baraldo L; Mindiola DJ; Davis WM; Cummins CC;  J .  of the Am. Chem. Soc. 1999, Vol 121, Iss 43, pp 0053-10067.

"Dimolybdenum-mu-cyanide complexes supported by N-tert-butylanilide ligation: in pursuit of cyanide reductive cleavage", Peters JC; Baraldo LM; Baker TA; Johnson AR; Cummins CC, J. of Organometallic Chem1999, Vol 591, Iss 1-2, pp 24-35