Tunable donor properties

The benzannulation approach has also been used to generate a steroid D ring bearing both a tunable donor (ferrocenyl substituent) and an acceptor site (benzoquinone functionality), which allows for modification of the electron-transfer properties [94]. 

One of the outstanding properties of these substances is the extreme tunability of the electronic states under high pressure. In many cases a red shift on the order of 2000 cm-1/GPa has been observed (Yersin and Riedl, 1995). In addition, an effective nonradiative energy transfer from the cyano donor complexes to the f elements has been observed. In the case of Eu[Au(CN)2]3-3H20 this process even totally quenches the otherwise very intense and broad emission from the [Au(CN)2] layers. However, because of the very strong red shift of the donor electronic states, it is possible to shift the donor states over different levels of the f element. Especially, resonant and nonresonant energy transfer conditions can be achieved to study the transfer mechanism. 

P.-T. Wu, T. Bull, E S. Kim, C. K. Luscombe, S. A. Jenekhe, Organometallic Donor-Acceptor Conjugated Polymer Semiconductors Tunable Optical, Electrochemical, Charge Transport, and Photovoltaic Properties. Macromolecules 2009,42, 671-681. 

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