Producción Científica Profesorado

Versatile behavior of 2-guanidinobenzimidazole nitrogen atoms toward protonation, coordination and methylation



Andrade López, Noemí

1997

Versatile behaviour of 2-guanidinobenzimidazole nitrogen atoms towards protonation, coordination and methylation, N. Andrade-López, A. Vázquez-Olmos, A. Ariza-Castolo, H. Tlahuext-Romero, N. Barba-Berens, R. Contreras, Heteroatom Chem., 8, 1997, 397-410. ISSN (on line) 1098-1071. DOI: 10.1002/(SICI)1098-1071(1997)8:5<397::AID-HC4>3.0.CO;2-6


Abstract


The structure, dynamic behavior, protonation, methylation, and coordination sites of 2-guanidinobenzimidazole 1a were investigated. Structures of compounds [2-guanidinium-1,3,10-trihydrobenzimidazole]sulfate 1b, [2-guanidinium-1,3-dihydro-benzimidazole]sulfate 1c1d, [2-guanidinium-1,3-dihydro-benzimidazole]tetrafluoroborate 1e, [2-guanidinium-1,3-dihydro-benzimidazole]chloride 1f, [2-guanidinium-1,3-dihydro-benzimidazole] perchlorate 1g, 2-guanidino-1-methyl-benzimidazole 2a, [2-guanidinium-1,3-dimethyl-benzimidazole]iodide 2b, [2-guanidinium-1-methyl-3-hydro-benzimidazole]chloride 2c, [2-guanidinium-1,10-dihydro-benzimidazole]acetate 3, 2-guanidino-1-hydro-3-borane-benzimidazole 4a, 2-guanidino-1-methyl-3-borane-benzimidazole 4b, (2-guanidino-benzimidazole)dimethyltin 5, [bis(2-guanidino-10-hydro-benzimidazole)nickel(II)] 6, and [bis(2-guanidino-1,10-dihydro-benzimidazole)zinc(II)]nitrate 7 were determined based on 1H, 13C, and 15N NMR spectroscopy. The X-ray diffraction structures of 2a, 2b, 3, 6, and 7 were obtained. The results show that 1a has an open structure without an intramolecular hydrogen bond in DMSO or DMF. The imidazolic N-3 is the preferred basic site in solution for protonation, methylation, and coordination and not N-10 as was suggested from semiempirical calculations. Under strong acidic conditions, diprotonation occurs at N-3 and N-10. In the solid state, 3 and 6 were protonated preferently at N10 rather than at N-1.



Producto de Investigación




Artículos relacionados

Hypervalence at tin(IV) by transannular bonding of sulfur in an eight-membered ring: The case of dib...

Understanding and Predicting Distorted T- versus Y-Geometries for Neutral Chromous Complexes Support...

Study of the D?Sb (D = O, S) Transannular Interaction in Sb-Monohalogenated Dibenzostibocines ? An E...

Structural differences in eight- and ten-membered heterocyclic tin compounds displaying transannular...

Six-membered ring chelate complexes of Pd(II) and Pt(II) derived from di-(2-pyridyl)pyrimidin-2-ylsu...

Synthesis, Characterisation and Properties of As-Monohalogenated Dibenzoarsocines S(C6H4S)2AsHal (Ha...

Organometallic tin complexes derived from 2-guanidinobenzimidazole

Synthesis and crystal structures of cis-palladium(II) and cis-platinum(II) complexes containing dipy...

Hypervalence at tin(IV) by transannular bonding of sulfur in an eight-membered ring: The case of dib...

Synthesis and crystal structures of cis-palladium(II) and cis-platinum(II) complexes containing dipy...