1,10-Phenanthroline-dithiine iridium and ruthenium complexes: synthesis, characterization and photocatalytic dihydrogen evolution.

We report the synthesis and the spectroscopic and electrochemical properties of six mononuclear iridium(iii) and ruthenium(ii) complexes bearing S,S'-extended phenanthroline ligands. Starting from 5,6-dibromide-1,10-phenanthroline, the dithiine derivatives N,N'-1,10-phenanthrolinedithiino[2,3-b]quinoxaline and N,N'-1,10-phenanthrolinedithiino[2,3-b]benzene were prepared by primary N,N'-complexation of the dibromo derivative and subsequent nucleophilic substitution at the complex. The photoluminescence of the phenanthroline-dithiine containing complexes shows distinctively increased lifetimes for all Ir(iii) and Ru(ii) complexes. The activity of the series of Ir(iii) and Ru(ii) complexes as photosensitizers in visible-light photocatalytic water reduction is demonstrated by dihydrogen evolution with a [Fe3(CO)12] catalyst and triethylamine as a sacrificial donor.

Trapping of transient, heavy pnictogen-centred biradicals.

Since the heavy biradicals [E(µ-NTer)]2 (E = Sb, Bi) are only of fleeting existence in solution, they were generated in situ and trapped by [2 + 2] addition reactions utilizing alkynes such as tolan (Ph-C[triple bond, length as m-dash]C-Ph). The structure, biradical character and bonding of [E(µ-NTer)]2 biradicals as well as their addition products are discussed on the basis of computations and experimental data.

A neutral low-coordinate heterocyclic bismuth-tin species.

The reaction of distannadiazane bearing bulky (R)Ar*-groups ((R)Ar* = C6H2{C(H)Ph2}2R-2,6,4; R = iPr, tBu) with ECl3 (E = Sb, Bi) was studied resulting in the isolation of previously unknown N,N-bis(dichloropnictino)amines (3) and a novel heterocyclic carbenoid bismuth species (4) bearing a Bi((III)) and a Sn((IV)) center. The structure and bonding was investigated by means of X-ray structure elucidations and DFT calculations.