Synthesis and 2D NMR spectra of (CO)2(NO)Cr[(η5-C5H4)CH+(BF4−)(η5-C5H4)]Ru(η5-C5H5) α-cynichrodenyl-α-ruthenocenylmethylium tetrafluoroborate

Reduction of (CO)2(NO)Cr[(η5-C5H4)C(O)(η5-C5H4)]RuCp (hereafter called cynichrodenylruthenocenylketone) (12) with sodium borohydride gives cynichrodenyl ruthenocenyl methanol (8). Protonation of 8 with fluoroboric acid produces α-cynichrodenyl-α-ruthenocenylmethylium tetrafluoroborate (10). Diastereotopism of the 1H and 13C nuclei was observed in all the complexes (7–10). C(2,5) and C(3,4) were unequivocally assigned on the Cp(Cr) ring of the cynichrodene moiety in the 13C NMR spectrum of the carbocation derivative 10, and an opposite correlation was observed for the chemical shift assignments of C(2)–C(5) of the Cp ring between ruthenocene and cynichrodene.

The dimetallocenyl carbonium ion (CO)2(NO)Cr[(η5-C5H4)CH+(BF4−)(η5-C5H4)]RuCp has been prepared. The chemical shifts of H(2–5) and C(2–5) of the Cp rings were unequivocally assigned using 2D HetCOR-NMR spectroscopy. An opposite correlation was observed in the 13C NMR spectra between ruthenocene and cynichrodene.Figure optionsDownload as PowerPoint slideHighlights
► (CO)2(NO)Cr[(η5-C5H4)CH+(BF4−)(η5-C5H4)]RuCp 10 was synthesized.
► The unequivocal assignments of C(2–5) on the Cp ring of 10 in the 13C NMR spectrum were made.
► An opposite correlation between ruthenocene and cynichrodene was observed.
► Spectral comparisons between cynichrodenyl derivatives are presented.
► Comparisons between (CO)2(NO)CrCp. FcH and PhH derivatives are also presented.