| Abstract
| - An organometallic carboxyphosphine, rac-[2-(diphenylphosphino)ferrocenyl]acetic acid (rac-Hpfa*), was synthesized from rac-N,N-dimethyl[2-(diphenylphosphino)ferrocenyl]methylamineby successive alkylation to rac-benzyldimethyl{2-[(diphenylphosphino)ferrocenyl]methyl}ammonium bromide (2*), a replacement of the ammonium group with CN-, and, finally,hydrolysis of the obtained rac-[2-(diphenylphosphino)ferrocenyl]acetonitrile (3*). The acidwas further converted to the respective methyl ester 4, phosphine oxide 5*, and phosphinesulfide 6*. The metathesis of the in situ generated salt rac-Kpfa with di-μ-chloro-bis{2-[(dimethylamino)methyl-κN]phenyl-κC1}dipalladium(II) (7) afforded a heterobimetalliccomplex with the chelating carboxylate pfa--κ2O,P and the cyclometalated C,N-ligand,[SP-4-3]-{2-[(dimethylamino-κN)methyl]phenyl-κC1}{rac-[2-(diphenylphosphino-κP)ferrocenyl]acetato-κO1}palladium(II) (8*), while the cleavage of the chloro bridges in 7 with 4gave a complex with a P-bonded phosphino ester, [SP-4-4]-chloro{2-[(dimethylamino-κN)methyl]phenyl-κC1}{rac-methyl [2-(diphenylphosphino)ferrocenyl]acetate-κP}palladium(II)(9*). Compound 9 was further converted by reacting with AgClO4 to the cationic bis(chelate)complex [SP-4-3]-{2-[(dimethylamino-κN)methyl]phenyl-κC1}{rac-methyl [2-(diphenylphosphino-κP)ferrocenyl]acetate-κO2}palladium(II) perchlorate (10*). Complex 10 was alternatively obtained by a replacement of acetonitrile ligands in bis(acetonitrile){2-[(dimethylamino)methyl]phenyl-κ2C1,N}palladium(II) perchlorate (11) with 4. (The asteriskindicates that the solid-state structure has been determined by X-ray crystallography.)
- The new organometallic carboxyphosphine rac-[2-(diphenylphosphino)ferrocenyl]acetic acid (rac-Hpfa) was prepared from rac-N,N-dimethyl[(2-(diphenylphosphino)ferrocenylmethylamine by successive alkylation, substitution of the ammonium group in the N-benzylammonium salt with CN-, and hydrolysis of the obtained nitrile. rac-Hpfa and its methyl ester were tested as ligands in palladium(II) complexes with cyclometalated C,N-ligands. The ligands coordinate as simple phosphines (9) or anionic (8) and neutral O,P-chelating ligands (10).
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