New Reactions of Cyclopentadienylnickel Chelates with Secondary Phosphane Tethers

Abstract

In continuation of our research in cyclopentadienylalkylphosphane nickel chelates with secondary phosphane tethers the first cationic representatives of this class of compounds are reported. These were obtained by reaction of the respective bromo complex with tris(4-trifluoromethylphenyl)phosphane as well as with a number of alkyl and aryl isonitriles in the presence of indium tribromide. This Lewis acid is crucial for the success of the reactions leading to the respective tetrabromoindate salts. The compounds were characterized spectroscopically, including rare 14 N, 13 C couplings being observed. Finally, deprotonation experiments are reported, which provide some evidence for deprotonation taking place, although the expected phosphinidene chelates could not be isolated due to rapid decomposition.

Synthetic investigations of the diisocyanide‐bridged Cp*‐cobalt rectangles

“…Using silver salt as a dehalogenating agent will facilitate the formation of halide-bridged complexes, as has been wellestablished for organometallic group 9 metal (Co, Rh, Ir) complexes [3,14,[16][17][18][19][20]. Therefore, the treatment of 2 with two equivalents of AgOTf in the absence of 1,4-diisocyanobenzene affords the iodide-bridged rectangular tetranuclear complex [(Cp*Co) 4 (μ-I) 4 (μ-1,-4-CNC 6 H 4 NC) 2 ](OTf) 4 (4). Complex 4 can be converted to 3 by adding equimolar amounts of 1,4-diisocyanobenzene.…”

“…When the 1,4-diisocyanobenzene ligand is treated with two equivalents of CpCo(CO)I 2 or Cp*Co(CO)I 2 at room temperature, the CO group has been replaced by the (4). Using silver salt as a dehalogenating agent will facilitate the formation of halide-bridged complexes, as has been wellestablished for organometallic group 9 metal (Co, Rh, Ir) complexes [3,14,[16][17][18][19][20].…”

“…1,4-diisocyanobenzene is a linear spacer bridge ligand, similar to 4,4 0 -bipyridine, that can form coordination complexes with various metal centers [1][2][3][4][5]. In comparison to the 4,4 0 -bipyridine ligand [6], 1,4-diisocyanobenzene is known to stabilize complexes by participating as not only strong σ-donors but also π-acceptor ligands which are capable of coordination to transition metals in a variety of oxidation states [7,8].…”