Syntheses, characterization, and electrochemistry of compounds containing 1-diphenylphosphino-1′-(di-tert-butylphosphino)ferrocene (dppdtbpf)

Abstract The reaction of copper(I) salts CuX (X = Cl, Br, I, CN, SCN), [Cu(CH 3 CN) 4 ]PF 6 with 1-diphenylphosphino-1′-di- tert -butylphosphinoferrocene (dppdtbpf) in 1:1 M ratio in DCM–MeOH (50:50 V/V) at room temperature afforded mono and binuclear compounds having formula [Cu 2 ( μ -Cl) 2 ( κ 2 - P , P -dppdtbpf) 2 ] ( 1 ), [Cu 2 ( μ -Br) 2 ( κ 2 - P , P -dppdtbpf) 2 ] ( 2 ) [Cu 2 ( μ -I) 2 ( κ 2 - P , P -dppdtbpf) 2 ] ( 3 ), [Cu 2 ( μ -CN) 2 ( κ 2 - P , P -dppdtbpf) 2 ] ( 4 ), [Cu 2 ( μ 2 -SCN) 2 ( κ 2 - P , P -dppdtbpf) 2 ] ( 5 ), and [Cu( κ 2 - P , P -dppdtbpf)(CH 3 CN) 2 ]PF 6 ( 6 ). Reacting palladium(II) complex [Pd(C 6 H 5 CN) 2 Cl 2 ] with dppdtbpf gave mononuclear compound [Pd( κ 2 - P , P -dppdtbpf)Cl 2 ] ( 7 ). The reaction of dppdtbpf with sulfur powder under reflux in chloroform afforded a ferrocene diphosphine disulfide dppSdtbpSf ( 8 ). All of the synthesized compounds were characterized by elemental analyses, IR, 1 H and 31 P NMR, ESI-MS and electronic absorption spectroscopy. Molecular structures for the compounds 5 , 6 , 7 and 8 were determined crystallographically. Compound 5 exists as centrosymmetric dimer in which the two copper atoms are bonded to two dppdtbpf ligands and two bridging thiocyanate groups in μ 2 -manner. In cationic compound 6 , the copper atom is coordinated to one dppdtbpf ligand in κ 2 -manner and two acetonitrile molecules, whereas in 7 , the palladium(II) adopted cis square-planar geometry by coordinating to one dppdtbpf ligand in κ 2 -manner and two chlorine atoms. Compound 8 revealed a sandwiched structure with both phosphine groups sulfurized. The electrochemical properties of 1 – 6 were studied by cyclic voltammetry. Compounds 1 – 6 exhibited moderately weak to strong luminescence properties, however compounds 7 and 8 are non-emissive in the solution state.