COMPLEXES OF 9-PROPYLFLUORENYL ION PAIRS WITH TERTIARY POLYAMINES IN APOLAR SOLVENTS

Article abstract of DOI:10.1016/S0022-328X(00)81469-2

The complexation of tetramethylethylenediamine (TMEDA), hexamethyltriethylenetetramine (HMTT) and tetramethyltetraazacyclotetradecane (TMTCT) with ion pairs of 9-(n-propyl)fluorenyllithium (PFl^-, Li⁺) and n-butyl-9-(n-propyl)fluorenylmagnesium (BuPFlMg) in cyclohexane was studied by optical spectroscopy.The results can be explained in terms of externally complexed tight ion pairs and ligand-separated ion pairs, the latter complexes being much less soluble.With HMTT and PFl^-, Li⁺, the only complexes formed are (PFl^-, Li⁺)2 HMTT (λ_m 357 nm) and PFl^-, HMTT, Li⁺ (λ_m 383 nm).The reaction of PFl^-, Li⁺, TMEDA with TMTCT to form the loose ion pair complex PFl^-, TMTCT, Li⁺ has a rate constant in toluene of 250 M^-1 sec^-1.With the magnesium compound, the amines form only a loose ion pair complex, e.g., BuMg⁺, TMEDA, PFl^- (λ_m 382 nm).