Lithium indenide (Li-Ind) or cyclopentadienide (Li-Cp) derivatives react as nucleophiles with 8-(methylsulfinyl)-1,5-naphthyridine (Naph), leading to donor-functionalized ligands IndNaph or CpNaph, respectively. The new ligands comprise two N-donor atoms, which, for geometric reasons, cannot bind to the same metal atom. In complexes, where the metal atom is bound by the Cp or Ind moiety, the N5-donor atom is located in a distal position. The coordination behavior to Rh or Zr metal centers has been investigated. The Cp-based ligands show the expected chelating coordination mode with η5-Cp and N coordination, whereas the indenyl units act as dihapto, trihapto, or pentahapto ligands. The dinuclear Rh­(I) complex 12 shows a rare coordination geometry with two η3 ligands bridging a Rh2(CO)3 fragment.

Cyclopentadienyl ligands functionalized with a 1,5-naphthyridine donor have been used for the formation of chromium(III) half-sandwich complexes. In addition to standard analytical characterization, the complexes have been investigated by paramagnetic 1H NMR spectroscopy combined with DFT calculations. After activation, highly active single-site catalysts are obtained that lead to the formation of ultrahigh molecular weight polyethylene (UHMW-PE). Evaluation of polymer formation after different polymerization times at low temperature shows that the number of active centers is low at the beginning, but increases with polymerization time.

Sodium cyclopentadienide reacts as nucleophile with 4,7-dibromo-2,1,3-benzothiadiazole (BTZ) and leads to the new donorfunctionalized ligand Cp BTZ . Related quinoxalyl Cp-systems have been prepared using Pd-catalyzed coupling with zincated Cp-metal complexes. The new ligands comprise two N-donor atoms; one of them is located in a distal position relative to the metal centre so that it cannot coordinate in a chelating manner.. With