The present invention is a compound of formula whereinX is an ethynediyl group, R1, R2 and R3 are as defined in the specification. The units include a ballistic protection material which preferably covers most of the user’s upper arm, elbow region, lower arm, shoulder, upper leg, knee region, and lower leg except for ventilation zones preferably located on the inner portion of the upper arm and the inner part of the upper leg. A distributed configuration and administration system permits any authorized user of the community of users to have the capability of configuring and administrating electronic markets. The base includes an aperture and the support member is inserted in the aperture. for deblocking, a photoacid generator capable of generating a halogenated sulfonic acid upon photolysis and optionally, a base.