X-ray crystal structures and solution dynamics of sodium organofluorotitanates [Na{Ti 2(C 5Me 5) 2F 7}] and [NaTi 6(C 5Me 5) 5F 20(H 2O)]·(THF)

Abstract

[Na{Ti 2(C 5Me 5) 2F 7}] ( 1) was prepared from sodium fluoride and [{Ti(C 5Me 5)F 3} 2] [H.W. Roesky, et al., Angew. Chem. Int. Ed. Engl. 31 (1992) 864–866]. The solid-state 1 consists of a polymeric chain of two rows of dititanate anions [Ti 2(C 5Me 5) 2F 7] − connected by sodium ions in the middle of the chain. Each sodium ion is coordinated by five fluorine atoms from three [Ti 2(C 5Me 5) 2F 7] − anions. The variable-temperature 19F NMR of CD 3CN solution of 1 revealed interconversions of monomeric species [Na(CD 3CN) n {Ti 2(C 5Me 5) 2F 7}] ( 1solv) with different number of CD 3CN ligands on the sodium ion. The addition of HMPA to the CD 3CN solution of 1 allows 19F NMR observation of 1·HMPA ( 1a) and 1·HMPA·CD 3CN ( 1b) in the slow exchange. The solid-state structure of [NaTi 6(C 5Me 5) 5F 20(H 2O)]·(THF) ( 2·THF) reveals the sodium ion coordinated by four fluorine atoms from the anion [Ti 2(C 5Me 5) 2F 7] − and by three fluorine atoms from the cluster [Ti 4(C 5Me 5) 3F 13(H 2O)].