Formation of manganese enediyne complexes from manganese alkynylcarbene complexes

• Published in: Inorganica Chimica Acta 2003-03, Vol.345, p.320-326
• Main Authors: Casey, Charles P., Dzwiniel, Trevor L., Kraft, Stefan, Kozee, Michael A., Powell, Douglas R.
• Format: Article
• Language: English
• Subjects: Enediyne; Manganese alkyne complexes; Manganese alkynylcarbene complexes
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(02)01273-2

Dimerization of the alkynylcarbene complex (C 5H 4Me)(CO) 2MnC(Tol)CCTol ( 10) occurred at 65 °C to give a mixture of E- and Z-enediyne complexes [(C 5H 4Me)(OC) 2Mn] 2[η 2,η 2-TolCC(Tol)CC(Tol)CCTol] ( 13). Thermolysis of alkynye complexes 10 at higher (100 °C) temperature led to the formation of manganese-free E- and Z-enediynes TolCC(Tol)CC(Tol)CCTol ( 14- E and 14- Z ). Attempted synthesis of the tethered bis-(alkynylcarbene) complex Cp(OC) 2MnC(Ph)CCCH 2CH 2CH 2CCC(Ph)Mn(CO) 2Cp led instead to the cyclic enediyne complex [Cp(OC) 2Mn] 2[η 2,η 2-PhCCC(CH 2CH 2CH 2)CCCPh] ( 19), from which the metal-free enediyne 1,2-bis(phenylethynyl)cyclopentene ( 20) was released by thermolysis at 90 °C. Manganese alkynylcarbene complexes dimerize to enediyne manganese complexes at 65 °C. The free enediynes are released upon heating to 100 °C. Attempted synthesis of a tethered bis-(alkynylcarbene) complex led directly to a cyclic enediyne complex from which the metal-free enediyne was released at 90 °C.