A short and efficient preparation of 3,8‐dialkylated or 3,8‐diarylated 1,10‐phenanthrolines‐4,7‐diones is described. Their chlorination or bromination furnishes the corresponding, highly soluble 4,7‐dichloro‐ or 4,7‐dibromo phenanthrolines that constitute versatile precursors to macrocyclic oligophenanthrolines with exo‐coordination sites. They can be further reacted by nucleophilic aromatic substitution or Heck‐coupling reactions.

The synthesis and characterisation of a rigid nanoscale macrocycle with two exotopic phenanthroline binding sites is reported. Scanning tunnelling microscopy (STM) at the solid-liquid interface reveals the formation of highly ordered monolayers of macrocycles with dimensions that are in good agreement with the calculated structure. Using the HETPHEN concept several bisheteroleptic coordination complexes with other phenanthrolines and a nanoscale basket assembly were prepared in presence of copper(I) ions. NMR spectroscopy, mass spectrometric data and elemental analysis point to three distinct isomers of the basket assembly in solution. A silver basket was prepared and readily converted to its copper analogue. Electrospray ionisation (ESI)-MS and spectrophotometric investigations provided additional mechanistic insight into the assembly process. Hence, the exotopic bisphenanthroline macrocycle in combination with HETPHEN concept proves to be very effective in controlling the compositional aspects of multicomponent self-assembly.

Homoleptic and heteroleptic ruthenium trisphenanthrolines were prepared with azacrown ethers attached to the 4,7-positions of the phenanthrolines to maximise the electronic communication between the ruthenium and the crown ethers as complexation sites. Redox and spectral data were processed to explain the non-steady trends in the absorption and emission spectra in the series. Addition of Ba2+ entailed large shifts in the redox potential (up to 370 mV) and in the emission spectra (up to 87 nm). Due to the crowded situation of the azacrown ether units in, this complex showed a non-linear behaviour both in the redox and emission properties upon loading with Ba2+ that is postulated to originate from the intermediate formation of sandwich type complexes.

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Footnotest Satisfactory C, H, N analyses were obtained for all iron(1r) complexes.8 The charge to radius values for K+ and Ba2+ are 0.72 X 10-2 and 1.48 x 10-2 A s pm-1, respectively. AE, separation of anodic and cathodic peak potential.