Chelating or bridging Pd(ii) and Pt(ii) metalloligands from the functional phosphineligandN-(diphenylphosphino)-1,3,4-thiadiazol-2-amine. New heterometallic Pd(ii)/Pt(ii) and Pt(ii)/Au(i) complexes†
Abstract
The reaction of two equivalents of the functional NNCHS
(2) with [PdCl2(NCPh)2] in the presence of NEt3 gives the neutral, P,N-chelated complex cis-[Pd
(Ph2PN
C
N
N
CHS
)2] ([Pd(2−H)2], 3b), which is analogous to the Pt(II) analoguecis-[Pt
(Ph2PN
C
N
N
CHS
)2] ([Pt(2−H)2], 3a) reported previously. These complexes function as chelating metalloligands when further coordinated to a metal through each of the CH-N atoms. In the resulting complexes, each endo-cyclic N donor of the thiadiazole rings is bonded to a different metal centre. Thus, the heterodinuclear
(Ph2PN
C
N
N
CHS
)2Pd
Cl2] ([Pt(2−H)2·PdCl2], 4a) and cis-[Pd
(Ph2PN
C
N
N
CHS
)2Pt
Cl2] ([Pd(2−H)2·PtCl2], 4b) were obtained by reaction with [PdCl2(NCPh)2] and [PtCl2(NCPh)2], respectively. In contrast, reaction of 3a with [AuCl(tht)] occurred instead at the P-bound N atom, and afforded the platinum/digold complex cis-[Pt
{Ph2PN(AuCl)
C
N
N
CHS
}2] ([Pt(2−H)2(AuCl)2], 5). For comparison, reaction of 4a with HBF4 yielded cis-[P
t(Ph2PNH
CN
N
CHS
)2Pd
Cl2](BF4)2 ([H24a](BF4)2, 6), in which the chelated PdCl2 moiety is retained. Complexes 3b, 4a·CH2Cl2, 4b·0.5C7H8, 5·4CHCl3 and 6 have been structurally characterized by