By employing the subcomponent self-assembly approach utilizing 5,10,15,20-tetrakis(4-aminophenyl)porphyrin or its zinc(II) complex, 1H-4-imidazolecarbaldehyde, and either zinc(II) or iron(II) salts, we were able to prepare O-symmetric cages having a confined volume of ca. 1300 Å . The use of iron(II) salts yielded coordination cages in the high-spin state at room temperature, manifesting spin-crossover in solution at low temperatures, whereas corresponding zinc(II) salts led to the corresponding diamagnetic analogues. The new cages were characterized by synchrotron X-ray crystallography, high-resolution mass spectrometry, and NMR, Mössbauer, IR, and UV/Vis spectroscopy. The cage structures and UV/Vis spectra were independently confirmed by state-of-the-art DFT calculations. A remarkably high-spin-stabilizing effect through encapsulation of C was observed. The spin-transition temperature T is lowered by 20 K in the host-guest complex.

A simple approach toward preparation of heteroleptic two-dimensional (2D) rectangles and three-dimensional (3D) triangular prisms is described utilizing the HETPYP (HETeroleptic PYridyl and Phenanthroline metal complexes) concept. By mixing metal-loaded linear bisphenanthrolines of varying lengths with diverse (multi)pyridine (py) ligands in a proper ratio, six different self-assembled architectures arise cleanly and spontaneously in the absence of any template. They are characterized by (1)H and DOSY NMR, ESI-FT-ICR mass spectrometry as well as by Job plots and UV-vis titrations. Density functional theory (DFT) computations provide information about each structure. A stoichiometry-controlled supramolecule-to-supramolecule interconversion based on the relative amounts of metal bisphenanthroline and bipyridine forces the rectangular assembly to reorganize to a rack architecture and back to the rectangle, as clearly supported by variable temperature and DOSY NMR as well as dynamic light scattering data. The highly dynamic nature of the assemblies represents a promising starting point for constitutional dynamic materials.

A series of heterometallic metallamacrocycles have been constructed from self-assembly reactions between the fluorinated Au­(I) organometallic compounds [(AuC6F4py)2(μ2-diphosphane)] [diphosphane = bis­(diphenylphosphanyl)­methane (dppm) (1), 1,2-bis­(diphenylphosphanyl)­ethane (dppe) (2), trans-1,2-bis­(diphenylphosphanyl)­ethylene (dppet) (3), 1,3-bis­(diphenylphosphanyl)­propane (dppp) (4), 1,4-bis­(diphenylphosphanyl)­butane (dppb) (5), and 4,4′-bis­(diphenylphosphanyl)-1,1′-biphenyl (dppdph) (6)] and the cis-blocked complexes [M­(P–P)­(H2O)2]­(OTf)2 (M = Pd) (P–P = dppp, dppf) (a,c), (M = Pt) (P–P = dppp, dppf) (b,d). Changes of the backbone of the diphosphanes were seen to have an influence on the resulting species. While the self-assembly reactions involving [(AuC6F4py)2(μ2-dppm)] (1), [(AuC6F4py)2(μ2-dppb)] (5), and [(AuC6F4py)2(μ2-dppdph)] (6) donors gave exclusively [2 + 2] heterometallomacrocycles, the assemblies arising from [(AuC6F4py)2(μ2-dppe)] (2) as well as the combinations between [(AuC6F4py)2(μ2-dppp)] (4) and [M­(dppp)­(H2O)2]­(OTf)2 (a, b) and [(AuC6F4py)2(μ2-dppet)] (3) and [M­(dppf)­(H2O)2]­(OTf)2 (c, d) consisted of an equilibrium between two macrocyclic species ([2 + 2] and a higher-order aggregate [3 + 3], [4 + 4],...). Multinuclear (1H, 19F, 31P) and diffusion NMR spectroscopy in combination with a complete set of ESI-FT-ICR mass spectrometry experiments were used to elucidate the nature of the different assemblies. DFT calculations were performed in order to calculate the molecular geometry and estimate the relative stability of different conformations of [2 + 2], [3 + 3], and [4 + 4] supramolecular species for two of the used diphosphanes.

A stoichiometric variant of the HETPYP concept (HETeroleptic PYridine and Phenanthroline metal complexes) opens the venue to heteroleptic metallosupramolecular HETPYP-I assemblies both in solution and the solid state, involving the trigonal [Cu(phenAr(2))(py)](+) coordination motif (phenAr(2) = 2,9-diarylphenanthroline; py = various oligopyridines). Combining the same building blocks at another stoichiometric ratio furnished metallosupramolecular HETPYP-II aggregates in the solid state, now based on the tetrahedral [Cu(phenAr(2))(py)(2)](+) coordination motif. Thus, a stoichiometry-controlled structural changeover based on the relative amounts of oligopyridines leads from a discrete assembly with trigonally coordinated copper(I) centers to a coordination polymer with tetrahedrally coordinated copper(I) ions, as shown by solid state studies. In solution, the analysis of both stoichiometric variants indicates that the HETPYP-I structure is congruent with that in the solid state, while the HETPYP-II assembly, as established through DOSY NMR and dynamic light scattering measurements, is only oligomeric at low temperature. At room temperature, i.e. due to entropic costs, the latter assembly prefers to keep "unsaturated" coordination sites that are in rapid exchange, making it an interesting system as a dynamic protecting group and for constitutional dynamic materials through the exchange and reshuffling of components.

[2.2]Paracyclophane-based bis(pyridine) ligands form dinuclear complexes upon coordination to palladium(ii) ions, however, with distinct differences concerning their chiral self-sorting ability.