Arthur Höhn

Novel routes to alkynyl and vinylidene iridium complexes. The first example of :C=CH2 ligand transfer from a 4d to a 5d transition metal atom

Square-planar vinylidene iridium(I) complexes trans-[IrCl(CCHR)(PPri3)2](R = H, Me, Ph, SiMe3, CO2Me) are prepared from IrH2Cl(PPri3)2 and alk-1-ynes HC2R, via IrH(C2R)Cl(PPri3)2 as intermediates; the parent member of the series with R = H has also been obtained from C5H5Rh(CCH2) PPri3 and IrCl(PPri3)2, i.e. by transfer of a :CCH2 ligand from a 4d to a 5d transition metal atom.

A new template encapsulation strategy for larger cavity metal ion cages

Stereospecific sequential condensation of paraformaldehyde and propionaldehyde with a tripodal bis(triamine)cobalt(III) template rapidly encapsulates the metal, and a subsequent facile reduction of imine functions gives an expanded cavity hexaazabicyclic cage system with unusual structural and chromophore electron properties, complemented by an exceptional stability and relatively fast CoII/III electron exchange rates.

Phospha-capped cobalt(III) cage molecules: synthesis, properties, and structure

Base-induced condensation of [Co(sen)]3+[sen = 4,4′,4″-ethylidynetris(3-azabutan-1-amine)] with paraformaldehyde and phosphine leads to the phospha-capped bicyclic cage complexes [Co(Mephosphasar)]3+(Mephosphasar = 8-methyl-3,6,10,13,16,19,1-hexa-azaphosphabicyclo[6.6.6]icosane) and its phosphine oxide derivative [Co(Me, Ophosphasar)]3+; the complexes have surprisingly different spectral and electrochemical properties which are attributed to their different conformations and the X-ray crystal structure of [Co(Me, Ophosphasar)][ZnCl4]Cl has been determined.

Stabilization of an unusual conformation of an encapsulated metal ion cobalt(methylarsasarcophagine): synthesis and structure

Base-catalysed condensation of [Co(sen)]3+(1)[sen = 4,4′,4″-ethylidyne-tris(3-azabutan-1-amine)] with formaldehyde yields the stable tri-imine [Co(sim)]3+(2)[sim = 6,6′,6″-ethylidyne-tris(2,5-diazahex-1-ene)] that is converted into the arsenic capped cage molecule [Co(Mearsasar)]3+(3)(Mearsasar = 8-methyl-1,3,6,10,13,16,19-arsahexa-azabicyclo[6.6.6]icosane) by reaction with AsH3; an X-ray crystallographic analysis of (3) reveals an unusual oblique conformation of the encapsulating ligand, which affects the properties of the complex in a marked manner.

A new strategy for the metal template synthesis of organic metal ion cages

High yield template syntheses of hexa-azabicycloeicosanes and related imines are described arising from non-aqueous condensations of mixed aldehydes with the 4,4′,4″-ethylidyne-tris(3-azabutan-1-amine)cobalt(III) ion in basic media.