Carbon-rich organometallic materials derived from 4-ethynylphenylferrocene

Using 4-ethynylphenylferrocene (1) as the building block, a new series of rigid-rod alkynylferrocenyl precursors consisting of fluoren-9-one unit, 2-bromo-7-(4-ferrocenylphenylethynyl)fluoren-9-one (2a), 2,7-bis(4-ferrocenylphenylethynyl)fluoren-9-one (2b), 2-trimethylsilylethynyl-7-(4-ferrocenylphenylethynyl)fluoren-9-one (3) and 2-ethynyl-7-(4-ferrocenylphenylethynyl)fluoren-9-one (4) have been prepared in moderate to good yields. The acetylene complex 4 is a useful precursor for the synthesis of well-defined carbon-rich- ferrocenyl heterometallic complexes, trans-[(eta(5)-C5H5)Fe(eta(5)-C5H4)C(6)H(4)Cequivalent toCRCequivalent toCPt(PEt3)(2)Ph] (5), trans-[(eta(5)- C5H5)Fe(eta(5)-C5H4)C(6)H(4)Cequivalent toCRCequivalent toCPt(PBu3)(2)Cequivalent toCRCequivalent toCC(6)H(4)(eta(5)-C5H4)Fe(eta(5)-C5H5)] (6), trans-[(eta(5)-C5H5)Fe(eta(5)-C5H4)C(6)H(4)Cequivalent to CRCequivalent toCM(dppm)(2)Cl] (M = Ru (7), Os (8)) (R = fluoren-9-one-2,7-diyl). All new complexes have been characterized by FTIR, NMR and UV-Vis spectroscopies and fast atom bombardment mass spectrometry (FABMS). The molecular structures of 1, 2a, 4, 6 and 8 have been determined by single-crystal X-ray studies where an iron-iron through-space distance of nanosized dimension (ca. 42 Angstrom) is observed in the trimetallic molecular rod 6. The electronic absorption, luminescence and electrochemical properties of these carbon-rich molecules were investigated and the data were correlated with the theoretical results obtained by the method of density functional theory. (C) 2003 Elsevier B.V. All rights reserved.