THEORETICAL CALCULATIONS OF AN OSMIUM MOLECULAR SWITCH

Abstract

ABSTRACT We have investigated the molecular, electronic and optical properties of the [Os(tpy-py) 2 ] 2+ complex (tpy-py = 4’-(4-pyridyl)-2,2’:6’,2’’-terpyridine) and its protonated derivative [Os(tpy-pyH) 2 ] 4+ through Density Functional Relativistic calculations including Scalar and Spin Orbit corrections. The molecular geometry of the parent complex is not strongly modified by the protonation at the basic nitrogen atoms of the pyridine moieties of the terpyridine ligands in the complex. On the other hand, the optical properties of these complexes can be controlled by a change in the chemical acid-base environment, converting them into suitable materials to act as molecular switches or pH sensor devices. e-mail: dmacleod@unab.cl INTRODUCTION The innovative designs and creative thinking of numerous scientists led to artificial molecular mechanisms being used in device applications. [1] In this sense, molecular Switches comprise an interesting class of artificial molecular machines and can be defined as molecules that can be switched between two or more different states. In a particular case, Photochemical switches are molecular or supramolecular species in which properties or functions can be switched on and off by light. [1,2]In this context, recently [3,4] the photoluminescence in the far red spectral region and photosensitised generation of singlet oxygen, with associated near-IR emission, of the [Os(tpy-py)