Several types of molecular species containing a metallocene connected to a nitrogen-containing bridge, have been synthesized and characterized both spectroscopically and by theoretical methods, belonging to the following categories:
* Metallocene-bridge-acceptor triads. The metallocene, normally ferrocene (although sometimes ruthenocene), constitutes the electron source (donor) and frequently the acceptor is an oxidized metallocene (ferrocenium or ruthenocenium) unit. The aza-bridge is either 2-aza-1,3-butadiene or carbodiimide. These species have been used for the study of IET (intramolecular electron transfer) processes by means of voltamperommetric measurements and/or the experimentally observed intervalence bands in the near infrared (NIR) region [pub020, pub021, pub023, pub029, pub030, pub033, pub035, pub056]. Some examples are shown below.
* Molecular receptors for ion (and neutral molecules) sensing. The following example was used for nitrate-selective electrode [pub015]
The general strategy consists of bringing in close proximity a suitable receptor unit and a chromogenic or fluorescent moiety as a signalling unit. In most cases also a ferrocene substituent is also incorporated so as to give a redox and/or colorimetric (even naked-eye) response in the presence of the guest molecule or ion [pub016, pub018, pub019, pub023, pub024, pub025, pub026, pub084]. Some examples are:
