960209-73-8Relevant articles and documents
Synthesis of multifunctional aza-substituted ruthenocene derivatives displaying charge-transfer transitions And selective Zn(II) ions sensing properties
Oton, Francisco,Espinosa, Arturo,Tarraga, Alberto,Molina, Pedro
, p. 6234 - 6242 (2008/10/09)
The synthesis, electrochemical, electronic, and cation sensing properties of multinuclear nitrogen-rich [2.2]- and [3.3]-mixed ferrocene and ruthenocene metallocenophanes are presented. Structural features of these new structural motifs are that the two redox organometallics fragments are linked by unsaturated nitrogen functionalities, for example, carbodiimide or aldimine, as well as the nitrogen atom is directly attached to the ruthenocene unit. The key bis(iminophosphorane) 3 is readily prepared by the Staudinger reaction between triphenylphosphine and 1,1′-diazidoruthenocene 2, which has been prepared from 1,1′- dilithioruthenocene and 2,4,6-trisopropylbenzenesulfonyl azide (trisyl azide). Subsequent aza-Wittig reactions of 3 with the appropriate carbonyl or thiocarbonyl compounds provided the opened ruthenocenebased isothiocyanate 4, and the closed carbodiimide 5 and aldimines 6 and 7. Spectroelectrochemical studies of carbodiimide 5 and aldimine 7 revealed the presence of low-energy bands in the near-IR region in the partially oxidized forms, at 1029 and 1481 nm, respectively, which indicate the existence of intramolecular charge transfer between the iron and the ruthenium centers. The experimental data and conclusions are supported by DFT computations. Moreover, the aldimine 7 behaves as a selective colorimetric chemosensor molecules for Zn2+ ions. The low-energy (LE) band of the absorption spectrum of this compound is red-shifted by 99 nm, only in the presence of Zn2+ ions. This change in the absorption spectrum is accompanied by a dramatic color change, which allows the potential for naked eye detection.
