Installing tungsten Fischer carbene complexes into a calixarene frameworkElectronic supplementary information (ESI) available: 1D and 2D NMR spectra, details of the biological assays and dimerization studies and tables of crystal data. CCDC 1438070 and 1437666. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ra17326h

The synthesis of the first examples of calix[4]arene-based Fischer carbene complexes is reported here. Fischer carbene complex 2 is the key intermediate to reach uracil-like derivatives 3 and 4 . X-ray and NMR studies revealed that the uracyl-like synthon gives rise to a supramolecular dimer. The organometallic calixarene complexes showed a promising cytotoxicity towards human tumor cell lines. The first examples of calix[4]arene-based Fischer carbene complexes are here reported. The organometallic calixarene complexes showed a promising cytotoxicity towards human tumor cell lines.