In certain embodiments, an alkyl contains 1 to 20 carbon atoms (whenever it appears herein, a numerical range such as ???1 to 20??? refers to each integer in the given range; e.g., ???1 to 20 carbon atoms??? means that an alkyl group can contain only 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 20 carbon atoms, although the term ???alkyl??? also includes instances where