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Zwitterionic [(4‐ n ‐Alkyl‐1,4‐bisazoniacyclohex‐1‐yl)methyl]pentafluorosilicates: A New Class of Surface‐Active Compounds with a Hexacoordinate Silicon Atom
Author(s) -
Willeke Meike,
Lunkenheimer Klaus,
Tacke Reinhold
Publication year - 2001
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200111)627:11<2517::aid-zaac2517>3.0.co;2-k
Subject(s) - alkyl , chemistry , hexacoordinate , medicinal chemistry , surface tension , polymer chemistry , silicon , organic chemistry , physics , quantum mechanics
Abstract A series of [(4‐ n ‐alkyl‐1,4‐bisazoniacyclohex‐1‐yl)methyl]pentafluorosilicates (alkyl = hexyl, heptyl, octyl, nonyl, decyl; compounds 14 – 18 ) were synthesized and studied for their surface activity. The zwitterionic pentafluorosilicates with hexacoordinate Si atoms 14 – 18 were prepared by reaction of the respective [(4‐ n ‐alkylpiperazin‐1‐yl)methyl]trimethoxysilanes [obtained by treatment of (MeO) 3 SiCH 2 Cl with the respective n ‐alkylpiperazine in the presence of NEt 3 ] with HF in water/ethanol. Surface tension measurements with solutions of 14 – 18 in 0.01 M hydrochloric acid proved that these compounds are surfactants, the increase of the n ‐alkyl chain length resulting in an increase of surface activity ( 14 → 18 ). The equilibrium surface tension vs concentration isotherms for 14 – 17 (solutions of “surface‐chemically pure” samples in 0.01 M hydrochloric acid) were analyzed quantitatively.