Reactions of the metallacrown ethers, [PdCl (PPh (CH CH O) CH CH PPh -P, P′)] (n = 3, 5), with PdCl or Pd(PhCN) Cl yield the new dimetallacrown ethers, [Pd Cl (μ-Cl) (PPh (CH CH O) CH CH PPh -P, P′)] (n = 3 (3), n = 5 (4)). Similar reactions of [PdCl (PPh (CH ) PPh -P, P′)] and [PdCl (PPh (CH CH O) CH CH -P) ] with PdCl or Pd(PhCN) Cl yield [Pd Cl (μ-Cl )(PPh (CH ) PPh -P, P′)] (5) and [Pd Cl (μ-Cl) (PPh (CH CH O) CH CH -P) ] (6), respectively. The chloride-bridged dimetallacrown ethers, 3 and 4, are cleanly converted into the iodide-bridged dimetallacrown ethers, [Pd I (μ-I) (PPh (CH CH O) CH CH PPh -P, P′)] (n = 3 (7), n = 5 (8)) by reaction with excess NaI. In solution, 3 and 4 exist as mixtures of syn monomers and cyclic oligomers while 7 and 8 exist as mixtures of both syn and anti monomers and cyclic oligomers. The solid state structures of syn-[Pd I (μ-I) (PPh (CH CH O) CH CH PPh -P, P′)] (syn-7) and of anti-[Pd I (μ-I) (Ph P(CH CH O) CH CH ) -P) ) (anti-9) have been determined. These structures are consistent with the major species present in the solutions. They also suggest that syn-7 experiences ring-strain, which is consistent with the results from the P( H) NMR studies. © 2003 The Royal Society of Chemistry. 2 2 2 2 n 2 2 2 m 2 2 2 2 2 2 2 2 2 n 2 2 2 m 2 2 2 12 2 m 2 2 2 2 2 2 3 2 2 2 2 2 2 2 2 2 12 2 m 2 2 2 2 2 2 2 2 3 2 2 2 2 2 2 2 n 2 2 2 m 2 2 2 2 2 2 3 2 2 2 2 2 2 2 2 2 2 2 3 2 2 31 1
