Syntheses of dimetallamacrocycles by intramolecular oxidative couplings of dinuclear bis(1,3-butadiynyl) complexes (see abstract) Academic Article uri icon

abstract

  • Reactions of the chiral racemic carbonyl complex [η5-C5Me5)Re(NO)(NCCH3) (CO)+·BF4- and diphosphanes Ph2P(CH2)nPPh2 [2.4:1.0 mol ratio; n = 10 (a), 14 (b)] give the (bridging phosphane)dirhenium complexes [(η5-C5Me5)Re(NO)(CO){μ- [PPh2(CH2)nPh2P]-P,P}(OC)(ON) Re(η5-C5Me5)]2+·2 BF4- (73-80%), which are reduced (LiAlH4) to the dimethyl complexes [(η5-C5Me5)Re(NO)(CH3) {μ-[PPh2-(CH2)nPh2P]-P,P} (ON)(H3C)Re(η5-C5Me5)] (92-96%). Reactions with HBF4·OEt2/C6H5Cl, HC≡CC≡CSiMe3, and tBuOK give, via π-HC≡C adducts (89-94%), the bis(trimethylsilyl-butadiynyl) complexes [η5-C5Me5)Re(NO)(C≡CC≡ CSiMe3){μ-[PPh2(CH2)n Ph2P]-P,P}(Me3SiC≡CC≡C)(ON)-Re (η5-C5Me5)] (9a,b; 95-66%). Desilylation (wet nBu4NF) yields labile bis(butadiynyl) complexes, which are coupled [Cu(OAc)2/pyridine] to the μ-octatetraynediyl complexes [(η5-C5Me5)Re(NO){μ- [PPh2(CH2)nPh2P]-P,P}{μ-(C1 ≡CC≡CC≡CC≡C8)-C1, C8}(ON)Re(η5C5Me5)] (3a,b; 10-23% from 9a,b). These represent some of the few cases of intramolecular oxidative homocouplings of terminal alkynes in metal coordination spheres. The electrochemical properties of 3a,b, which undergo two one-electron oxidations, are compared to nonmacrocyclic analogs that lack the diphosphane bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

author list (cited authors)

  • Horn, C. R., & Gladysz, J. A.

citation count

  • 31

publication date

  • June 2003