Ammonium, alkylammonium, and amino acid complexes of a hexacopper fluoro-metallacrown cavitand.
Reaction of CuF2 with one equivalent of 3{5}-(pyrid-2-yl)-5{3}-(tertbutyl)pyrazole (HL) and excess NH4OH in MeOH affords crystalline [NH4{Cu(micro-F)(microL)}6(CH2Cl2)2]HF2 in moderate yield. This compound contains the 12-MC-6 metallacrown [{Cu(micro-F)(micro-L)}6] (1) with a NH4 + ion at its center, and CH2Cl2 molecules complexed in bowl-shaped cavities above and below the Cu6F6 ring. Similar reactions using the bases MeNH2, glycine, l-alanine or beta-alanine afforded solvated crystals of [1(H3NMe)2]Cl2, [1(gly)2], [1(l-ala)2], and [1(beta-ala)2], respectively. The metallacrown 1 in these products contains methylammonium and zwitterionic amino-acid guests in its two bowl-shaped cavities; each of the amino acids hydrogen-bonds to three F atoms. A related reaction using 1,6-diaminohexane resulted in fixation of CO2 from the air to give solvated [1(H3NC6H12NHCO2)2], again with a zwitterionic guest. NMR, ESI-MS and UV/vis measurements suggest that the metallacrown 1 retains its integrity in several organic solvents, although it is unclear to what extent guest binding takes place in solution.
Jones
Leigh F
LF
School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
Barrett
Simon A
SA
Kilner
Colin A
CA
Halcrow
Malcolm A
MA
D000478:Alkylation; D000596:Amino Acids / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012118:Resorcinols / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
D000596:Amino Acids; D004988:Ethers, Cyclic; D000644:Quaternary Ammonium Compounds; D012118:Resorcinols; C442939:cavitand; D003300:Copper