Synthesis and properties of trimesitylthallium. A comparison of the trimesitylelement compounds of group 13

The reaction of TlCl3 with MesMgBr (Mes = 2,4,6-Me(3)C(6)H(2)) in THF at 0 degrees C gives trimesitylthallium, TlMes(3) (2). 2 has been characterized with NMR, IR and MS techniques as well as by an X-ray structure determination. 2 crystallizes isostructural to InMes(3) (1a). The molecules of 2 are coordinated by the three mesityl substutients in a planar fashion. A new modification of InMes(3) (1b) could be obtained by recrystallization of InMes(3) from toluene/n-pentane in the space group C2/c. The literature known modification la and the new metallane 2 crystallize in the space group P2(1)/n. The molecules in 1b possess C-2-symmetry. The trimesitylelement compounds EMes(3) (E = B, Al, Ga, In, Tl) have been compared with each other.