Ferrocene-bridged Pd–NCN pincer complexes

Abstract

The meta-diaminoaryl ferrocene Fe[η 5-C 5H 4(NCNH)] 2 [NCNH=1-C 6H 3(CH 2NMe 2) 2-3,5] ( 3) can be synthesised by the reaction of Fe[η 5-C 5H 4(ZnCl)] 2 ( 1) with I–C 6H 3(CH 2NMe 2) 2-3,5 ( 2) in a 1:2 molar ratio in the presence of catalytic amounts of [Pd(PPh 3) 2]. The two meta-dimaminoaryl NCNH pincer units in 3 can be used to assemble multimetallic complexes. Thus, 3 produces on reaction with tBuLi and (Me 2S) 2PdCl 2 trimetallic Fe[η 5-C 5H 4(NCN–4-PdCl)] 2 {NCN=1-C 6H 2(CH 2NMe 2) 2-3,5} ( 6) along with heterobimetallic Fe[η 5-C 5H 4(NCNH)][η 5-C 5H 4(NCN–4-PdCl)] ( 5). Complex 6 contains two bis- ortho-chelated pincer NCN–PdCl units, whereas 5 possesses one bis- ortho-chelated NCN pincer entity and one non-metallated NCNH moiety. Complex 6 is the first example in organometallic chemistry in which two bis- ortho-chelated diaminoaryl palladium units are bridged via the respective para C-atoms spanned by a redox-active ferrocenyl building block.