CONDUCTIVITY AND NMR-STUDY OF KF-NALET(3) COMPLEXES (N=1,2) IN TOLUENE SOLUTIONS

Toluene solutions of Ziegler-type complexes KF-Al(C2H5)(3) (''1:1'') a nd KF-2Al(C2H5)(3) (''1:2'') have been characterized by NMR-spectrosco py and conductimetry. The behaviour of 1:1 complex is very close to th at of AlEt(3). In solution there are dimeric species [KAlX(4)](2) (4X = 3Et + F). The conductivity of these associated molecules is very sma ll (2.8 x 10(-5) Omega(-1) . cm(-1)) and concentration independent. So lutions of 1:2 complex exhibit high conductivities at concentrations > 0.4 mol . l(-1) (1.4 x 10(-3) Omega(-1). cm(-1) at 0.5 mol . l(-1). [ K+]-[Et(3)-Al-F-Al-Et(3)](-) ionic species are present. In dilute solu tions 1:2 complex decomposes giving 1:1 + AlEt(3) and conductivity is drastically lowered. In this concentration range formation of solvates cannot be ruled out.