SYNTHESES AND CHARACTERIZATION OF TIN(II) COMPLEXES CONTAINING 10-PI-ELECTRON RING-SYSTEMS

The compounds [(i-Pr)(2)ATI]SnCl (1) and ]Sn}[eta(5)-C5H5)ZrCl2(mu-Cl- 3)ZrCl2(eta(5)-C5H5)] (2) in which [(i-Pr)(2)ATI] = N-isopropyl-2-(iso propylamino)troponimine have been prepared and characterized by H-1, C -13, and Sn-119 NMR spectroscopies and X-ray crystallography. Compound s 1 and 2 feature heterobicyclic C7N2Sn ring systems with basically th ree- and two-coordinate tin atoms, respectively. Solid state structure s of 1 and 2 show weak Sn...Cl interactions. The Sn-119 NMR signal of 2 appears at a significantly lower field compared to that of 1. This i s consistent with the reduction in coordination number at the Sn cente r of 2. The H-1 NMR data also provide evidence for the formation of a more symmetric solution species with the removal of Cl- from 1. X-ray structural features of C7N2Sn moiety in [(i-Pr)(2)ATI]SnCl and the {[( i-Pr)(2)ATI]Sn}(+) cation are very similar. The Sn-N bond distances of {[(i-Pr)(2)ATI]Sn}(+) cation are not indicative of any significant Sn -N multiple bonding. The pi-electrons of the C7N2Sn ring system, there fore, appears to be mostly delocalized over nitrogen and carbon atoms.