1,4-Bis(4-nitrosophenyl)piperazine: novel bridging ligand in dinuclear complexes of rhodium(iii) and iridium(iii)Electronic supplementary information (ESI) available: CCDC reference numbers 838208838214. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c1dt11696g

• Main Authors: Wirth, Stefan, Barth, Florian, Lorenz, Ingo-Peter
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c1dt11696g

The synthesis, spectroscopic characterization and crystal structures of the first 1,4-bis(4-nitrosophenyl)piperazine (BNPP) ( 4 ) bridged dinuclear complexes of rhodium( iii ) and iridium( iii ) are presented. The reaction of the 2 -halogenido-bridged dimers [( 5 -C 5 Me 5 )IrX 2 ] 2 [X = Cl ( 5a ), Br ( 5b ), I ( 5c )] and [( 5 - C 5 Me 5 )RhCl 2 ] 2 ( 6a ) with 4 yields the dinuclear complexes [( 5 -C 5 Me 5 )IrX 2 ] 2 -BNPP ( 7ac ) and [( 5 -C 5 Me 5 )RhCl 2 ] 2 -BNPP ( 8a ). All new compounds were characterized by their NMR, IR and mass spectra. The X-ray structure analyses of the obtained half-sandwich complexes revealed a slightly distorted pseudo-octahedral configuration ( three-legged pianostool ) for the metal( iii ) centers. The bridging BNPP ligand is - N coordinated by both nitroso groups and shows different conformations of the piperazine ring depending on the solvent used for crystallization. Moreover the crystal structures of 1,4-bis(4-nitrosophenyl)piperazine ( 4 ) and its precursor 1,4-diphenylpiperazine ( 3 ) are reported. The synthesis and full characterization of the first 1,4-bis(4-nitrosophenyl)piperazine bridged dinuclear complexes are presented. This may open the field of metal organic frameworks to C -nitroso chemistry.