Synthesis and structural characterization of ferrocene phosphines modified with polar pendants and their palladium(II) complexes. Part I: N-aminocarbonyl and N-acyl phosphinoferrocene carboxamides.

Acylation of 1′-(diphenylphosphino)-1-(aminocarbonyl)ferrocene, Ph 2 PfcCONH 2 ( 1 ; fc = ferrocene-1,1′-diyl), afforded a series of acyl-ureas including Ph 2 PfcCONHCONHEt ( 1a ), Ph 2 PfcCONHCONHPh ( 1b ), and Ph 2 PfcCONHCONMe 2 ( 1c ) as well as the acetyl derivative Ph 2 PfcCONHAc ( 1d ). Compounds 1a-d were converted to the corresponding phosphine oxides ( 2a-d ) and further examined as ligands in Pd(II) complexes. The reactions of 1a-d with [PdCl 2 (cod)] (cod = cycloocta-1,5-diene) at a 2:1 ligand-to-metal ratio gave the bis(phosphine) complexes [PdCl 2 (L-κ P ) 2 ] ( 3a-d ; L = 1a-d ), whereas the reactions with [Pd(L NC )Cl] 2 (L NC = [2-(dimethylamino-κ N )methyl]phenyl-κ C 1 ) produced the bridge-cleavage products, [PdCl(L NC )(L-κ P )] ( 4a-d ). Removal of the Pd-bound halide from 4a-d with Ag[SbF 6 ] furnished the corresponding cationic bis-chelate complexes [Pd(L NC )(L-κ 2 O,P )][SbF 6 ] ( 5a-d ). All compounds were characterized by NMR and IR spectroscopy, electrospray ionization mass spectrometry, and elemental analysis. The crystal structures of 1a , 2a-c , 3a ·2CHCl 3 , 3b ·2CHCl 3 , 3d ·2CHCl 3 , 4a ·3CHCl 3 , 4b ·2.5CHCl 3 , 5a ·CHCl 3 , 5b ·2CH 2 Cl 2 , and 5d were determined by single-crystal X-ray diffraction analysis, which revealed that the hydrogen-bonded arrays formed in the crystals of free ligands are often preserved in the structures of their complexes. [ABSTRACT FROM AUTHOR]