0 or 2 to 20 (when M is --NH-O or b is 2 to 20 (when M is --O--); c is 1 or 2; Z is oxygen or NH2 + ; and W is hydrogen or --NHC(???O)--R' where R' is an alkyl group having 1 to 6 carbon atoms; ##STR27## formed from coupling the thiol-derivatized support of Equation 2 and the reactive carbon center-derivatized oligonucleotide of Equation 9 (when M is --NH--) and wherein M is --NH-- or oxygen; R is