First heterobimetallic complexes of phosphocavitands

Design and Study of PhosphocavitandsA New Family of Cavity Systems

“…Later, anionic complexes have been prepared on the basis of amidophosphitocavitands and copper chloride 40 or silver bromide. 41 Note that the ligand remains fully symmetrical in any of the above-mentioned metal complexes.…”

“…This spectral pattern points to a structural difference between the phosphocin rings. An X-ray diffraction study of the rhodium complex 16 (R ) Me, X ) Oi-Pr) 42 showed that three phosphocin rings have a chair-boat conformation typical of symmetrical phosphocavitands 9,[16][17][18][19][20]31,[37][38][39][40][41] and the fourth one is in a boat conformation; the rhodium fragments are directed equatorially, while the isopropoxy groups have an axial orientation. Thus, the introduction of the bulky rhodium-containing fragments to four phosphorus atoms results in a distortion of the molecular cage of the cavitand and in the loss of symmetry for the whole system.…”

“…Therefore, compounds 18 are tridentate ligands and can be involved in further complexation 41,45 (Scheme 13). (Acetylacetonato)dicarbonylrhodium(I) 45 and silver bromide 41 have been used as secondary complexing agents. The reactions proceeded under mild conditions giving rise to tetranuclear complexes 19, in the molecules of which three phosphorus atoms are coordinated to rhodium or silver and one phosphorus atom to molybdenum.…”

“…An X-ray diffraction study has shown that cavitand 2 is complexed with silver and copper halides to form anionic complexes 15 due to accepting of the halide anion in the macrocycle cavity (Scheme ). Later, anionic complexes have been prepared on the basis of amidophosphitocavitands and copper chloride or silver bromide . Note that the ligand remains fully symmetrical in any of the above-mentioned metal complexes.…”

“…The binuclear metal complexes 17 , containing two uncoordinated trivalent phosphorus atoms in the molecule, are potential bidentate ligands. However, the two pentacarbonyl metal-containing fragments shield completely the cavitand cavity and the trivalent phosphorus atoms, which precludes further complexation …”