Fully Collapsed Imploded Cryptophanes in Solution and in the Solid State

Cryptophanes with flexible linkers derived from (±)‐tris‐(4‐formyl‐phenyl)‐cyclotriguaiacylene with either bisoxydi(ethylamine) or bis(aminopropyl)ether were isolated as single crystals, the crystal structures of which showed the proposed, but previously uncharacterised, out‐in conformation, in which both cyclotriguaiacylene fragments adopt a crown conformation with one crown sitting inside the other. The usual cage‐like out‐out conformation of the cryptophanes was observed when crystals were dissolved upon heating, and the molecules collapsed back to the out‐in isomers over time. In contrast, a cryptophane also derived from (±)‐tris‐(4‐formyl‐phenyl)‐cyclotriguaiacylene but with rigid dibenzalhydrazine linkers was isolated as the more usual out‐out isomer

Metallo-cryptophane cages from cis-linked and trans-linked strategies

Trigonal bipyramidal metallo-cage species [Pd₃(dppp)₃(L)₂]∙6OTf (where dppp = bis(diphenylphosphino)propane, OTf = triflate and L is tris(iso-nicotinoyl)cyclotriguaiacylene (L1) or tris(fluoro-iso-nicotinoyl)cyclotriguaiacylene (FL1)) have been characterised in solution to exist predominantly as the anti-isomers. The crystal structure of [Pd₃(dppp)₃(FL1)₂]∙6OTf, however, was found to be the achiral syn-isomer. The complex [Pd₃Cl₃(L2)₂] (where L2 = tris(methylbenzimidazolyl)cyclotriguaiacylene) is a trans-linked M₃L₂ cage, observed by mass spectrometry and in the solid state as the anti-isomer. Ligand L2 also forms a 1:1 co-crystal with cyclotriguaiacylene

Tris(rhenium fac-tricarbonyl) Polypyridine Functionalized Cyclotriguaiacylene Ligands with Rich and Varied Emission

Trinuclear rhenium fac-tricarbonyl bromide complexes have been synthesized coordinated to the host ligands tris(4-[4-methyl-2,2′-bipyridyl]methyl)cyclotriguaiacylene (L1), tris(4-[4-methyl-2,2′-bipyridoyl])cyclotriguaiacylene (L2), and tris(4-[2,2′,6′,2″-terpyridyl]benzyl)cyclotriguaiacylene (L3). The structure of L1 and complexes [{Re(CO)3Br}3(L1)] (1) and [{Re(CO)3Br}3(L3)] (3) have been elucidated through X-ray single-crystal diffraction, with complex 3 crystallizing as a conglomerate. The steady-state luminescent properties and time-resolved fluorescence studies of the complexes have been conducted and revealed an unusual dual-emission phenomenon for complex 2. Complexes 1 and 2 show red-shifted emission wavelengths in comparison with those typical of monometallic Re(CO)3-bipy-Br complexes, while complex 3 showed an unusual excitation-dependent variation of emission wavelength

2D networks of metallo-capsules and other coordination polymers from a hexapodal ligand

The hexapodal ligand hexakis(isonicotinoyl)cyclotricatechylene (L1) belonging to the cyclotriveratrylene family of host-molecules has been synthesised and used in the assembly of a series of coordination polymer materials with Re(I), Co(II), Cu(II), Ni(II) and Ag(I) salts. Single crystal structures of the coordination polymers [Re3(L1)2Br3(CO)3] 1, and an isomorphic [M3L2] series where M = Co, Cu or Ni, reveal 2D framework structures with a simplified topology of 36 or hxl. These are composed of M6(L1)2 metallo-cages linked together in a pair-wise fashion through each metal centre. Compound 1 is a rare example of a rhenium coordination polymer and was investigated for guest uptake from solution, complexing I2. The mixed-ligand species [Cu2(L1)(CF3CO2)3(isonicotinate)] forms a (3,4,5)-connected 2D coordination polymer, while [Ag2(L1)(DMF)2]·2BF4·2(H2O)·6(DMF) features a 2D network of (3,6)-connectivity and with kagome dual (kgd) topology