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Structural Study of some 2,6-Bis[(dimethylaminomethyl)phenyl]butyl Stannanes. Nonconventional Behaviour of Triorganotin (IV) Halides
Autoři: Růžička Aleš | Jambor Roman | Císařová Ivana | Holeček Jaroslav
Rok: 2003
Druh publikace: článek v odborném periodiku
Název zdroje: Chemistry - A European Journal
Název nakladatele: Wiley-VCH
Místo vydání: Weinheim
Strana od-do: 2411-2418
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Structural Study of some 2,6-Bis[(dimethylaminomethyl)phenyl]butyl Stannanes. Nonconventional Behaviour of Triorganotin (IV) Halides The four organotin (IV) compounds ([2,6-bis(dimethylaminomethyl)phenyl](n-butyl)R1R2stannane, where R1 = R2 = nBu (1), R1 = nBu, R2 = Cl (2), R1 = nBu, R2 = Br (3) and R1 = R2 = Br (4)), have been prepared and their structures have been investigated in various solvents and at various temperatures (NMR). The structures of these compounds in solution are solvent- and temperature-dependent. The solid state structures of 2 and 3 were studied using CP/MAS NMR spectroscopy and X-ray diffraction techniques. The tetraorganotin compound 1 exhibits tetrahedral geometry with very weak Sn-N coordination. The dynamic process of Sn-N bond(s) association/dissociation was observed using low-temperature NMR measurements. The tin central atom in 2 and 3 is [4+2]-coordinated in toluene solutions and the NMR low-temperature measurements reveal the same dynamic behavior as for 1 in this solution, with retention of the covalent halogen-tin bond. However, this bond is dissociated in methanol solutions, yielding ionic species, where the tin atom is only [3+2]-coordinated, and the halogen atom lies outside of the primary coordination sphere of the tin atom. In addition, while the same ionic structure as in methanol was found in the whole measured temperature range in the chloroform solution of 3, the structure of 2 varies in this solvent. In this compound, the covalent Sn-Cl bond (similar structure as in toluene solution), which is retained at room temperature in chloroform solution, is continuously dissociated with a decrease in temperature, leading to ionic bonding (a similar structure as in methanol solution). All the above-mentioned processes are reversible in all the solvents and at all temperatures. In the solid state, the covalent Sn-Cl bond is observed for 2, while an ionic bond was found in 3. Tin / Chelates / N-ligand / NMR / X-ray
eng Structural Study of some 2,6-Bis[(dimethylaminomethyl)phenyl]butyl Stannanes. Nonconventional Behaviour of Triorganotin (IV) Halides The four organotin (IV) compounds ([2,6-bis(dimethylaminomethyl)phenyl](n-butyl)R1R2stannane, where R1 = R2 = nBu (1), R1 = nBu, R2 = Cl (2), R1 = nBu, R2 = Br (3) and R1 = R2 = Br (4)), have been prepared and their structures have been investigated in various solvents and at various temperatures (NMR). The structures of these compounds in solution are solvent- and temperature-dependent. The solid state structures of 2 and 3 were studied using CP/MAS NMR spectroscopy and X-ray diffraction techniques. The tetraorganotin compound 1 exhibits tetrahedral geometry with very weak Sn-N coordination. The dynamic process of Sn-N bond(s) association/dissociation was observed using low-temperature NMR measurements. The tin central atom in 2 and 3 is [4+2]-coordinated in toluene solutions and the NMR low-temperature measurements reveal the same dynamic behavior as for 1 in this solution, with retention of the covalent halogen-tin bond. However, this bond is dissociated in methanol solutions, yielding ionic species, where the tin atom is only [3+2]-coordinated, and the halogen atom lies outside of the primary coordination sphere of the tin atom. In addition, while the same ionic structure as in methanol was found in the whole measured temperature range in the chloroform solution of 3, the structure of 2 varies in this solvent. In this compound, the covalent Sn-Cl bond (similar structure as in toluene solution), which is retained at room temperature in chloroform solution, is continuously dissociated with a decrease in temperature, leading to ionic bonding (a similar structure as in methanol solution). All the above-mentioned processes are reversible in all the solvents and at all temperatures. In the solid state, the covalent Sn-Cl bond is observed for 2, while an ionic bond was found in 3. Tin / Chelates / N-ligand / NMR / X-ray