Hydrazine. XV. The crystal structures and rates of hydrolysis of two substituted iminium salts: bis(1-m-chlorobenzylidene-3,5,5-trimethylpyrazolinium) hexachlorostannate and bis(1-p-hydroxybenzylidene-3,5,5-trimethylpyrazolinium) hexachlorostannate

Autor:	A. M. Stephen, L. R. Nassimbeni, R. C. Galloway
Rok vydání:	1979
Předmět:	chemistry.chemical_classification Diene Stereochemistry Substituent Iminium Salt (chemistry) General Medicine Nuclear magnetic resonance spectroscopy Crystal structure Medicinal chemistry chemistry.chemical_compound Hydrolysis Reaction rate constant chemistry
Zdroj:	Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 35:1766-1769
ISSN:	0567-7408
DOI:	10.1107/s0567740879007731
Popis:	[C laHl6ClN2] + [SnC16] 2crystallizes in the space group P2~/n with a = 9.522(5), b = 13.092(6), c = 14.597 (7) /~, fl = 108.2 (2) ° , Z = 2. [C13Ht7N20]2+[SnC16 ]2crystallizes in the space group P2/n with a = 12.917(6), b = 9.277 (5), c = 14.805 (7) ,/~, fl = 112.4 (2) °, Z = 2. The structures were refined to final R values of 0.043 and 0.028 respectively. The pyrazolinium ring and the CNNC diene system in both structures are essentially planar. NMR spectroscopy was used to measure the rates of hydrolysis of the salts in dimethyl sulphoxide solution. Overall second-order kinetics were observed with rate constants of 2 × 10 -6 for the m-chloro salt and 1 x 10 -7 m a mol -~ s -~ for the p-hydroxy salt. The hydrolysis rate is a function of the benzene-ring substituent but no difference in length is detectable for the bond being hydrolysed.
Databáze:	OpenAIRE
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