444057-34-5Relevant articles and documents
Synthesis and structural characterization of the first trialkylguanidinate and hexahydropyramidopyramidinate complexes of tin
Foley, Stephen R.,Yap, Glenn P.A.,Richeson, Darrin S.
, p. 619 - 627 (2002)
The first guanidinate complexes of tin have been prepared using N,N′,N″-trialkylguanidinates ([(RN)2C(NRH)]-; R = cyclohexyl; isopropyl) and 1,3,4,6,7,8-hexahydro-2H-pyramido[1,2-a]pyramidinate (hpp-) as ligands. The direct reaction between triisopropylguanidine and SnCl4 provided the complex {[iPrN]2C[NHiPr]}SnCl3 (1) along with concomitant formation of the guanidinium salt {C[NHiPr]3}+[SnCl5(THF)]- (2). The Sn(II) guanidinate complexes {(C6H11N)2C [NH(C6H11)]}2Sn (3) and {CN[N(CH2)3]2}2Sn (4) were prepared through metathesis reactions between 0.5 equiv. SnCl2 and (C6H11N)2C[NH (C6H11)]Li or hppLi, respectively. Complex 4 is the first reported mononuclear complex of this ligand. In contrast, the reaction of hppLi with 1 equiv. SnCl2 afforded a bridging dinuclear species, {CN[N(CH2)3]2SnCl}2 (5). A second mononuclear complex of the hppligand, {CN[N(CH2)3]2}2SnCl2 (6), was the product obtained from the reaction of 2 equiv. of hppLi with SnCl4. The full structural details of compounds 1 and 3-6 are reported. In the case of compounds 1 and 3 these results revealed a distinctly unsymmetrical bonding mode for the bidentate guanidinate ligand and suggest variable degrees of π delocalization with the ligand. The geometries of the Sn centers in 3, 4 are derived from distorted trigonal bipyramidal coordination with a stereochemically active lone pair occupying one coordination site. In contrast, complex 5 displayed a geometry derived from a tetrahedral ligand array with one vertex occupied by a lone pair of electrons. Complex 6 is six coordinate and possesses 2 equiv. chelating bidentate hpp- ligands and two cis-chloro groups.
