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Aluminium(III) porphyrin-carboxylate complexes, including a porphyrin pentamer, have been characterised by NMR spectroscopy, MALDI spectrometry and single crystal X-ray diffraction; these complexes can also be coordinated by a sixth, nitrogenous, ligand to the aluminium(III) centre.

Synthetic routes to a penta(4-pyridyl)cyclopentadienyl ligand are explored. The most successful route uses a palladium-catalysed pentapyridation of di(tert-butyl)phosphinoferrocene by using a procedure developed by Hartwig. The same method allows the synthesis of cyclopentadiene ligands substituted with 4-benzaldehydes or 4-phenylthiols. The pyridine ligands are formally five-connected nodes that may be linked by linear coordination metals to give closed spherical complexes of composition [(metal)(30)(ligand)(12)] as shown by molecular modelling. Experiment shows that the ligand complexes copper(I) and silver(I) with the expected 1:2.5 stoichiometry, and the (1)H NMR spectrum of the resulting product shows the ligands to be equivalent. NMR diffusion and light-scattering measurements support the formation of a species with a hydrodynamic radius of the order of 15 A, in agreement with the modelling studies. The resulting complex would be topologically identical to the C(60) fullerene structure.

A series of N₂O₂ tripodal tetradentate ligands derived from di-/tetra-tert-butyl substituted 2-[bis(2-hydroxybenzyl)aminomethyl]X (X = pyridine and benzimidazole) (H₂L(n) (n = 1-4)) and 8-[bis(3,5-di-tert-butyl-2-hydroxybenzyl)]aminoquinoline (H₂L⁵) were synthesised through a 4-step reaction scheme involving sequential formylation, reduction, bromination and alkylation. Treatment of H₂L(n) (n = 1-5) with [WO₂Cl₂(dme)] (dme = 1,2-dimethoxyethane) in the presence of triethylamine gave the corresponding cis-dioxotungsten(VI) complexes [WO₂(L(n))] (n = 1-5). The corresponding molybdenum analogues [MoO₂(L(n))] (n = 1-5) were also prepared from the reaction of [MoO₂(acac)₂] (acac = acetylacetonate) with H₂L(n) (n = 1-3) or [MoO₂Cl₂(dme)] (dme = 1,2-dimethoxyethane) with H₂L(n) (n = 4 and 5). All these compounds were fully characterised by a wide range of spectroscopic methods. The molecular structures of [MoO₂(L(n))] (n = 2, 4) and [WO₂(L²)] were also confirmed by single-crystal X-ray diffraction analysis. The catalytic activities of [MO₂(L(n))] (M = Mo, W; n = 1-4) towards epoxidation of styrene were also examined.

The self-assembly of two tripodal porphyrin hosts in the presence of C(60), in the solid state, has been studied using synchrotron X-ray crystallography, and in solution by using (1)H NMR and fluorescence spectroscopies. The binding affinities, stoichiometries and geometries strongly depend on the size of the porphyrin host. Intramolecular and/or intermolecular porphyrin-fullerene interactions are observed in the co-crystallites and in each case, the trimer exhibits a "tweezers-like" structural motif. The solid-state structures of the trimer-fullerene co-crystallites reveal close fullerene-porphyrin and fullerene-fullerene contacts.

New donor-acceptor hybrids of Zn(II)-metallated 5,15-diaryl porphyrins have been designed and synthesised via the porphyrin interactions with an electron acceptor molecule, di-n-hexyl N-substituted 1,2,4,8-naphthalenetetracarboxylic diimide (NDI). Binding interactions within these supramolecular complexes were investigated in the solid state by synchrotron X-ray diffraction and probed in solution by (1)H NMR spectroscopy. The systematic modulation of the porphyrin π-density was achieved, for the first time as multiple methoxy and fluorine groups were introduced as substituents to the 5,15-diaryls of the porphyrin. For these, the variation of the porphyrin-NDI binding strengths determined by (1)H NMR titrations was shown, using the Swain's type dual parameter approach, to be closely linked with the peripheral substitution pattern of the diaryl porphyrins validated by crystallography. The new 1:1 donor-acceptor complexes formed display characteristic features of the aromatic-stacked systems, i.e. the parallel arrangement and short interplanar separation between the substituted porphyrin and NDI. Synthetic modification of electron-density on the porphyrin surface by introducing substituents at peripheral sites of functionalised porphyrins represent a general solution towards electronically tunable aromatic surfaces: an understanding of their solution and solid state behaviour will significantly improve the rational design of new functional donor-acceptor supramolecular materials with potential applications ranging from new energy materials to dye-sensitised solar cells, photovoltaics and future drug delivery devices.

Suzuki and Sonogashira couplings have been used in short and efficient sequences to give access to a new family of porphyrin trimers on a practical scale.

The synthesis of a penta(1-methylpyrazole)ferrocenyl phosphine oxide ligand (1) [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))] is reported together with its X-ray crystal structure. Its self-assembly behavior with a dirhodium(II) tetraoctanoate linker (2) [Rh(2)(O(2)CC(7)H(15))(4)] was investigated for construction of fullerene-like assemblies of composition [(ligand)(12)(linker)(30)]. Reaction between 1 and 2 in acetonitrile resulted in the formation of a light purple precipitate (3). Evidence for the ligand-to-linker ratio of 1:2.5 expected for a fullerene-like structure [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))](12)[Rh(2)(O(2)CC(7)H(15))(4)](30) was obtained from (1)H NMR and elemental analysis. IR and Raman studies confirmed the diaxially bound coordination environment of the dirhodium linker by comparing the stretching frequencies of the carboxylate group and the rhodium-rhodium bond with those in model compound (5), [Rh(2)(O(2)CC(7)H(15))(4)](C(3)H(3)N(2)CH(3))(2), the bis-adduct of linker 2 with 1-methylpyrazole. X-ray powder diffraction and molecular modeling studies provide additional support for the formation of a spherical molecule topologically identical to fullerene with a diameter of approximately 38 Å and a molecular formula of [(1)(12)(2)(30)]. Dissolution of 3 in tetrahydrofuran (THF) followed by layering with acetonitrile afforded purple crystals of [(1)(2)(2)](∞) (6) [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))][Rh(2)(O(2)CC(7)H(15))(4)](2) with a two-dimensional polymeric structure determined by X-ray crystallography. The dirhodium linkers link ferrocenyl units by coordination to the pyrazoles but only four of the five pyrazole moieties of the pentapyrazole ligand are coordinated. The ligand-to-linker ratio of 1:2 in 6 was confirmed by (1)H NMR spectroscopy and elemental analysis, while results from IR and Raman are in agreement with the diaxially coordinated environment of the linker observed in the solid state.