SYNTHESIS, CRYSTAL-STRUCTURE AND SPECTROSCOPIC PROPERTIES OF DIORGANOTHALLIUM(III) DERIVATIVES OF 2,6-DIACETYL-PYRIDINE-MONOTHIOSEMICARBAZONE

Dimethyl (2, 6-diacetyl-pyridine-monothiosemicarbazonato) thallium (II I), [TlMe2(L)], and Diphenyl- (2,6-diacetyl-pyridine-monothiosemicarba zonato) thallium(III) chloroform solvate, [TlPh2(L)I,CHCl3 were prepar ed by reacting the corresponding diorganothallium(III) hydroxide with 2,6-diacetyl-pyridinemonothiosemicarbazone (HL). [TlMe2(L)I crystalliz es in the triclinic space,group PI (no; 2) with a=7.064(3), b=9.149(2) , c=12.377(2)Angstrom, alpha=79.378(11), beta=74.92(2), gamma=82.75(2) degrees, Z=2, R-1 = 0.0305, Rw(2) = 0.0673. [TlPh2(L)]. CHCl3 crystall izes in the monoclinic space group C2/c with a = 23.559(3), b = 13.582 (2), c = 16.808(3)Angstrom, beta = 106.04(1)degrees, Z = 8, R-1 = 0.06 20, Rw(2). = 0.1155. Both complexes consist of molecules in which the deprotonated ligand is S,N(3),N(4),O-bonded to the thallium atom [TlMe 2(L)], Tl-S = 2.872(2), Tl-N(3) = 2.590(6), Tl-N(4) = 2.686(2), Tl-O = 2.883(6)Angstrom; [TIPh2(L)]. CHCl3, Tl-S = 2.791(6), Tl-N(3) = 2.56( 2), Tl-N(4) = 2.579(14), Tl-O = 2.86(1)Angstrom]. A weak bond Tl ... O ' [TlMe2(L)], 3.050(2) Angstrom; [TlPh2(L)]. CHCl3, 3.42(1) Angstrom] between neighbouring molecules give rise to weakly bonded dimers. The H-1, C-13 and Tl-205 NMR spectra of both compounds in DMSO indicate th at the bonding scheme observed in solid state is only partially retain ed in solution, where at least two isomers are observed. (C) 1998 Else vier Science Ltd. All rights reserved.