ON HETEROCYCLIC-SYSTEMS CONTAINING LEAD .4. PATHS TO AND BETWEEN CYCLIC DIORGANOTIN AND LEAD SULFIDES [R2(SN PB)S]2,3/

Organolead and -tin sulfides were prepared by reaction of difunctional ized organometallic compounds of the form R2MX2 (M = Sn, Pb; R = organ yl; X = halogen, acetate) and H2S. Redistribution experiments were con ducted, and the exchange of ring segments was confirmed by Sn-119 and Pb-207 NMR spectroscopy and by mass spectrometry in and from CDCl3 sol ution. Redistribution of six-membered heterocyclic systems resulted in purely six-membered redistribution species, while redistribution of f our- and six-membered heterocycles yielded four-membered redistributio n species as well. During the synthesis of [(cHex)2SnS]3 it was possib le to intercept the equivalent of a reaction intermediate in which sul fur is partially replaced by oxygen. By X-ray structure analysis this was assigned to be Sn4(cHex)8Cl2O2(SH)2, which possesses a fully plana r ladderlike central core of ten atoms where the tin atoms acquire fiv e-coordination. On the basis of the structure of this intermediate equ ivalent species and on the basis of signals assigned to M4 redistribut ion species which occurred in all possible combinations (Sn4, Sn3Pb, S n2Pb2, SnPb3, Pb4) in the FD mass spectrometrical measurements, steps in the mechanisms of the electron-donor-catalyzed synthesis of the pur e heterocycles and of the redistribution reactions are suggested.