Tin and Mercury Compounds Supported by a Bulky Organometallic Ligand Incorporating a Pendant Guanidine Functionality

Abstract

The structure of a triclinic form of the organolithium derivative LiR, R = C(SiMe3)2(SiMe2{hpp}) (1) (hppH = 1,3,4,6,7,8,-hexahydro-2H-pyrimido[1,2-a]pyrimidine) comprises dimers [1]2 held together by Li···H3C interactions like those in the polymeric structure [1]∞ of the previously described orthorhombic form. Compound 1 reacts with the chlorides MCl2 (M = Hg or Sn) to give compounds HgRCl (2) or SnRCl (3), which have been characterised by NMR spectroscopy and X-ray crystallography. The structural parameters and conformations of the metallacycles MRLn are compared with those in related compounds containing bulky organosilicon ligands with pendant nitrogen donors. Compound 3 reacts with Li[P{H}Ar*] (Ar* = 2,4,6-tBu3C6H2) to give the crowded phosphanide SnR(P{H}Ar*) (4).