摘要:
Dispirotetradecanes of the formula I ##STR1## wherein R.sup.1 and R.sup.2 are each independently of each other alkyl containing 1 to 12 carbon atoms wherein one or more non-adjacent CH.sub.2 groups may also be replaced by --O--, --CO--, --CO--O--, --O--CO--, --O--COO-- and/or --CH.dbd.CH-- (trans), one of the radicals R.sup.1 and R.sup.2 also being H, F, Cl, Br, I, CN, NO.sub.2, NCS,A.sup.1 and A.sup.2 are each independently of each other trans-1,4-cyclohexylene wherein one or two non-adjacent CH.sub.2 groups may be replaced by --O-- and/or --S--, or 1,4-phenylene wherein one or more CH groups may also be replaced by N, with it also being possible optionally for A.sup.1 and A.sup.2 to be substituted laterally or axially by F, Cl, CN, CH.sub.3,Z.sup.1 and Z.sup.2 are each independently of each other --C--O--, --O--CO--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 -- or a single bond,m and n are each 0, 1 or 2,(m+n) 0, 1 or 2,X.sup.1, X.sup.2, X.sup.3 and X.sup.4 are each independently of each other H, F, Cl or CN, and one or both of the groups CX.sup.1 X.sup.2 and CX.sup.3 X.sup.4 may also be C.dbd.O, may be used as components of liquid-crystalline phases.
摘要:
The invention relates to a method and a device (16) for detecting volatile analytes in air samples, where a mass sensitive sensor (20) with at least one sensor area (21) which is equipped with a surface layer with selective sensitivity for the analyte(s) to be detected is brought into contact with the air sample to be analyzed, the mass change of the surface layer is detected in the form of electrical signals and the electrical signals are evaluated. It is provided in accordance with the invention that the sensor signal is already evaluated at a point in time at which the maximum sensor signal for the analyte concentration in question is not yet obtained.
摘要:
The present invention relates to dendritic, nitrogen-containing organic compounds containing at least 4 planar-chiral or axial-chiral groups, where these planar-chiral or axial-chiral groups are linked as Schiff's bases to the primary amino groups of compounds of the formula (I) (R.sup.1 R.sup.1)N--X--N(R.sup.1 R.sup.1) (I) where R.sup.1 is (R.sup.2 R.sup.2)N--(CH.sub.2).sub.2 -- or (R.sup.2 R.sup.2)N--(CH.sub.2).sub.3 --, R.sup.2 is hydrogen or (R.sup.3 R.sup.3)N--CH.sub.2).sub.2 -- or (R.sup.3 R.sup.3)N--(CH.sub.2).sub.3 --, R.sup.3 is hydrogen or (R.sup.4 R.sup.4)N--(CH.sub.2).sub.2 -- or (R.sup.4 R.sup.4)N--(CH.sub.2).sub.3 --, R.sup.4 is hydrogen or (R.sup.5 R.sup.5)--N--(CH.sub.2).sub.2 -- or (R.sup.5 R.sup.5)N--(CH.sub.2).sub.3 --, R.sup.5 is hydrogen or (R.sup.6 R.sup.6)N--(CH.sub.2).sub.2 -- or (R.sup.6 R.sup.6)N--(CH.sub.2).sub.3 -- and R.sup.6 is hydrogen, X is an aliphatic and/or aromatic group, which may contain heteroatoms, which are suitable as catalysts for asymmetrical homogeneous catalysis.