DFT calculations NMR spectroscopy NMR studies Research & information: general UV-Vis absorption studies UV–vis studies X-ray diffraction X-ray structure alkylammonium hydrochlorides anion anion receptor antibiotic anticancer antimicrobial ball milling barfate salts biofilm inhibition calix[3]arenes calix[4]arene calix[4]tubes calixarene calixarene-analogous metacyclophanes calixarene-like structure calixarenes chiral axles chiral recognition chiral wheels chirality conventional synthesis copper