Abstract: Compounds of the formulas: ##STR1## wherein R is independently branched or straight chain C.sub.1 -C.sub.4 alkyl; R.sub.1 is independently branched or straight chain C.sub.1 -C.sub.4 alkyl, phenyl or halo; R.sub.2 is independently branched or straight chain C.sub.1 -C.sub.17 alkyl wherein at least one R.sub.2 group has a bromo substituent on the carbon atom adjacent to the ring; and X is branched or straight chain C.sub.1 -C.sub.17 alkylidene wherein the ring carbon and the quaternary nitrogen are attached to the same carbon atom are useful as chemical labeling agents which react readily with free sulfhydryl groups or primary amino groups to produce intensely fluorescent (when compounds I and III are used) and phosphorescent (when compounds II and IV are used) substances.

Abstract: Compounds capable of functioning as membrane mobility agents in plant and animal cells are described. These compounds have a structure represented by the formula ##STR1## in which A represents a hydrophilic chain; Z represents either an ester linkage ##STR2## an amide linkage ##STR3## or an ether linkage (--O--); R.sub.1 represents either a straight-chain alkyl group or a straight-chain alkyl group interrupted by one or more cyclopropyl groups; R.sub.2 and R.sub.3 each represent either hydrogen, lower alkyl, or a halogen group; and x represents an integer from 2 to 10.The membrane mobility agents of the invention promote the lateral mobility through cell membranes of molecules ranging in size from phospholipids to surface antigens. They represent a new class of biologically active molecules which may be used to alter the mobility of membrane components in animal and plant cells to alter such cells in their response to external stimuli.