5,10,10,15,20,20-Hexamethylcalix[4]pyrrole 5,15-diethyl diester

5,10,10,15,20,20-Hexamethylcalix[4]pyrrole 5,15-diethyl diester

In the title compound, C(32)H(40)N(4)O(4), the pyrrole rings and ester groups adopt a 1,3-alternate conformation in which the alternating pyrrole and ester units are in opposite directions. The structure displays N-H⋯O hydrogen bonding and exhibits disorder [site occupancies of 0.81(2) and 0.71(2)] in the peripheral ethyl groups.

pp. 515-542 Zanfei 937

It is suggested that a transition is taking place towards new modes of organising transnational corporations’ innovative activities. First, different units of multinational firms, including foreign-based subsidiaries, are increasingly involved in the generation, use and transmission of knowledge. Secondly, multinationals are developing external networks of relationships with local counterparts,...

#515 - Frogs Give Warning

According to the POST, herpetologists (scientists who study amphibians and reptiles) have reported finding frogs with missing legs, extra legs, misshapen legs, paralyzed legs that stuck out from the body at odd places, legs that were webbed together with extra skin, legs that were fused to the body, and legs that split into two half-way down. They have also found frogs with missing eyes. One on...

CS 515 : Written Assignment

Invariants of Pfaffian Systems 515