Synthesis and Characterization of Functionally Substituted Cyclopentadienyl Derivatives of Silver and Copper

Abstract

A series of functionally substituted cyclopentadienyl derivatives of silver and copper have been synthesized and characterized. Reactions between sodium acetyl- or carbomethoxycyclopentadienylide, triphenylphosphine, and silver triflate (AgSO 3 CF 3 ) in DME produced Ag[C 5 H 4 C(O)CH 3 ](PPh 3 ) and Ag[C 5 H 4 CO 2 CH 3 ](PPh 3 ) in yields of 57−58%. Corresponding copper analogues were prepared using [BrCu(PPh 3 )] 4 . Similar reactions between sodium acetyl- or carbomethoxycyclopentadienylide and AgSO 3 CF 3 in the presence of the bidentate ligand 1,2-bis(diphenylphosphino)ethane afforded the chelated compounds Ag[C 5 H 4 C(O)CH 3 ][Ph 2 P(CH 2 ) 2 PPh 2 ] and Ag[C 5 H 4 CO 2 CH 3 ][Ph 2 P(CH 2 ) 2 PPh 2 ] in 55−72% yields. Dinuclear compounds of the type [Ag(C 5 H 4 PPh 2 )(PR 3 )] 2 (R = Ph, Et) resulted in 36−49% yield from reactions of silver chloride with the appropriate phosphine in refluxing toluene, followed by cooling to −78 °C and subsequent reactions with lithium diphenylphosphinocyclopentadienide. The compounds M(C 5 Ph 5 )(PEt 3 ) (M = Ag, Cu) containing five bulky phenyl substituents were obtained in 44−56% yield from reactions of sodium pentaphenylcyclopentadienide and [ClM(PEt 3 )] 4 in THF. In general, the new organosilver compounds containing functional substituents on the cyclopentadienyl ring as well as binuclear phosphine derivatives exhibited enhanced thermal and oxidative stabilities compared with the parent compound Ag(C 5 H 5 )(PPh 3 ). 31 P NMR studies of the compounds have been undertaken and are in agreement with the proposed structures.