There are described silanyl phenols and naphthols of formula (1a) or (1b),
wherein R.sub.1 is hydrogen; halogen; hydroxy; C.sub.1 C.sub.20alkyl;
C.sub.3 C.sub.12cycloalkyl; C.sub.1 C.sub.20alkoxy; trifluoromethyl;
pentafluoroethyl; mono- or di-C.sub.1 C.sub.5alkylamino; hydroxy-C.sub.1
C.sub.5alkyl; or phenyl, phenyl-C.sub.1 C.sub.20alkyl, phenoxy,
phenyl-C.sub.1 C.sub.20alkoxy, naphthyl or naphthyl-C.sub.1 C.sub.20alkyl
each unsubstituted or substituted by C.sub.1 C.sub.5alkyl, C.sub.3
C.sub.12cycloalkyl, C.sub.1 C.sub.5alkoxy, C.sub.3 C.sub.12cycloalkoxy,
halogen, oxo, carboxy, carboxy-C.sub.1 C.sub.7alkyl ester,
carboxy-C.sub.3 C.sub.12cycloalkyl ester, cyano, trifluoromethyl,
pentafluoroethyl, amino, N,N-mono- or di-C.sub.1 C.sub.20alkylamino or by
nitro; R.sub.2, R.sub.3 and R.sub.4 are each independently of the others
hydrogen; C.sub.1 C.sub.20alkyl; or C.sub.3 C.sub.12-cycloalkyl; R.sub.5,
R.sub.6 and R.sub.7 are each independently of the others C.sub.1
C.sub.20alkyl, C.sub.5 C.sub.10aryl, C.sub.1 C.sub.20alkoxy,
phenyl-C.sub.1 C.sub.20alkyl, phenyl-C.sub.1 C.sub.20alkoxy, C.sub.2
C.sub.5alkenyl, --O--Si--(C.sub.1 C.sub.5alkyl).sub.3; or O--Si--(C.sub.1
C.sub.5alkyl).sub.2-O--Si(C.sub.1 C.sub.5alkyl).sub.3 and n is 0 or 1.
The compounds exhibit a pronounced activity against Gram positive and
Gram negative bacteria, and also against yeasts and moulds ##STR00001##
