Synthesis and structure of monoorganobismuth compounds bearing pyridinedimethoxide ligands

Monoorganobismuth compounds bearing pyridinedimethoxide ligands [2,6-C5H3N( (CR2O)-O-1)(2)](2-) (R-1 = Me, Et, Pr-i) have been synthesized. The ligand exchange reaction of PhBi(OEt)(2), which was in situ generated from PhBiBr2 and 2 equiv of NaOEt, with [2,6-C5H3N((CR2OH)-O-1)(2)] (1a, R-1= Me; 1b, R -1= Et; 1c, R-1 = Pr-i) gave PhBi[2,6-C5H3N((CR2O)-O-1)(2)] (5a, R-1 = Me; 5b, R-1 = Et; 5c, R-1 = Pr-i) in 57-78% yields. A similar reaction of MeBi( OEt)(2) with 1a gave MeBi[2,6-C5H3N(CMe2O)(2)] (5d) in 96% yield. (EtO)Bi[2 ,6-C5H3N(CEt2O)(2)] (5e) was also synthesized by the reaction of Bi(OEt)(3) with 1b in 61% yield. The structures of 5a-5c and 5e were characterized by X-ray structure analysis. Compounds 5a-5c and 5e form dimers in the solid state through the intermolecular coordination of the oxygen atoms to the bi smuth atoms. The intermolecular Bi-O distances highly depend on the bulkine ss of R-1 groups and range from 2.699(2) Angstrom (5a) to 3.581(3) Angstrom (5c). In solution at room temperature, on the other hand, 5a-5e exist as m onomers judging from NMR spectra in CDCl3 and/or toluene-d(s).