Synthesis,Characterization and Stability of Spirodiene Complexes of Molybdenum(II):New Route to ansa-Morybdenocene and Ring-Functionalized Molybdenocene Compounds

摘要

The reactions of [Mo(CO)2(Cp)(NCCH3)2][BF4](1)with spi-ro[2.4]hepta-4,6-diene and spiro[4.4]nona-1,3-diene give the complexes [Mo{eta~4-C5H4(CH2)2}(CO)2(Cp)][BF4](3)and [Mo{eta~4-C5H4(CH2)4}(CO)2(Cp)][BF4](4),respectively.[Mo{eta~4-C5H4(CH2)2}(CO)2(Cp)][BF4](3)is stable towards ring opening at room temperature,but its formation is accompanied by small amounts of ring-opening products [Mo(eta~5-C5H4CH2-eta~1-CH2)(CO)(Cp)][BF4](5)and [Mo{eta~5-C5H4(CH2)2-eta~1-CO}(CO}(Cp)][BF4](6).With 1,1-dimethyl-spiro[2.4]hepta-4,6-diene,two isomers with the formula [Mo{eta~4-C5H4CH2C(CH3)2}(CO)2(Cp)][BF4] are formed(7 and 8).While the endo-isomer 7 is stable towards ring opening,the exo-isomer 8 slowly rearranges to the ring-opened product [Mo{eta~3-C3H4C(CH3)zCH2-eta~1-CO}(CO)(Cp)][BF4](9).The reaction of [Mo(CO)2(Ind)(NCCH3)2][BF4](2)with spi-ro[4.4]nona-1,3-diene also gives the diene coordinated spe- cies [Mo{eta~4-C5H4(CH2)4)(CO)2(Ind)][BF4](11),which is the first example of a structurally characterized,coordinated,un-substituted spirodiene.In contrast,reaction of 2 with spi-ro[2.4]hepta-4,6-diene leads directly to the ansa-cyclopen-tadienyl complex [Mo(eta~5-C5H4CH2-eta~1-CH2)(CO)(Ind)][BF4](12).Reaction of 12 with bromine or iodine leads to the formation of Cp-substituted molybdenocene derivatives [Mo{eta~5-C5H4(CH2)2X}(CO)(Ind)X][BF4](13:X = Br,14:X = I).The compounds [Mo(eta~5-C5H4CH2-eta~1-CH2)(CO)(Ind)][BF4](12)and [MoBr{eta~5-C5H4(CH2)2Br}(CO)(Ind)][Br]·0.5H2O(13a)were structurally characterized,and they open the way to new functionalized molybdenocene complexes that have biological applications.