Chloropalladated tetranuclear and copper(I) complexes of propargylamines [RC≡CCH2NC4H8NCH2C≡CR

Abstract

The reactions of propargylamines 1,4-bis(3-phenylprop-2-yn-1-yl)piperazine (1) and 1,4-bis(3-(trimethylsilyl)prop-2-yn-1-yl)piperazine (2) with PdCl2 and CuI is described. 1,4-Bis(3-phenylprop-2-yn-1-yl)piperazine reacts with one equivalent of PdCl2 to afford κ2-N,N-coordinated complexes [PdCl2{Me3SiCCCH2NC4H8NCH2C≡CSiMe3-κ2-N,N] (3) and [PdCl2{Me3SiCCCH2NC4H8NCH2C≡CSiMe3}-κ2-N,N] (4). The reactions of 1 and 2 with two equivalents of PdCl2 yielded rare chloropalladated tetranuclear complexes [Pd4(μ-Cl)4(PhC=C(Cl)CH2NC4H8NCH2(Cl)C=CPh)2] (5) and [Pd4(μ-Cl)4(Me3SiC=C(Cl)CH2NC4H8NCH2(Cl)C=CSiMe3)2] (6), respectively, resulting from the trans nucleophilic addition of chloride ion onto the electrophilic CC bond. The reactions of 1 and 2 with two equivalents of CuI produced 2-D coordination polymers [{Cu2(μ-I)}2(PhC≡C–CH2NC4H8NCH2C≡CPh)]n (7) and [{Cu2(μ-I)}2(Me3SiCCCH2NC4H8NCH2C≡CSiMe3)]n (8), respectively. Similar reactions in 1:1 M ratios produced dimeric complexes [Cu2(μ-I)2(PhC≡CCH2NC4H8NCH2C≡CPh)2] (9) and [Cu2(μ-I)2(Me3SiCCCH2NC4H8NCH2C≡CSiMe3)2] (10), respectively. The structures of compounds 3, 5 and 7 have been established by single crystal X-ray analysis.