Propargyl Unit Research Articles

Heterometallic metal carbonyl compounds derived from (η6-arene)tricarbonylchromium bearing propargyl units

The compounds [Co2(CO)8] and [Mo2Cp2(CO)4] readily react with (η6-arene)tricarbonylchromium complexes containing propargyl (prop-2-ynyl) 1a–c units to give new heterotrimetallic complexes [Cr{(η6-C6H5CCC(H)(R)Y)Co2(CO)6}(CO)3] (2a, R = Me and Y = NMe2; 2b, R = H and Y = NMe2; 2c, R = H and Y = OH) and [Cr{(η6-C6H5CCCH2NMe2)Mo2(Cp)2(CO)4}(CO)3] 3 in moderate to good yield (51–80%). Compounds 2a and 3 have been characterised by X-ray crystallography. Structural data reveal that the Cr(CO)3 unit adopts a nearly staggered conformation in 2a and eclipsed in 3.

Propargyl-, Allenyl- und Alkinyl-Phosphane; Synthese, Reaktivität, Isomerisierung/ Propargyl-, Allenyl- and Alkynyl-Phosphanes; Synthesis, Reactivity, Isomerization

The synthesis and reactivity of non-coordinated and coordinated propargyl phosphanes are discussed. The isomerization of the propargyl unit in (R)P(Cl)(CH2C ≡ CH ) (3) (R = 2,4,6-tBu3-C6H2O) in the presence of NEt3 yields the allenyl substituted p roduct (R)P(Cl)(CH = C = CH2) (4). However, in the presence of HNEt2 the dimethylenecyclobutane 7 is formed. Different synthetic pathways for the preparation of LnMP(Ph)m(CH2C ≡ CH)3-m complexes (m = 2: LnM = (η5-C5H5)(CO)2Mn: 10a; LnM = (CO)5Cr: 10b; m = 1: LnM = (η5-C5H5)(CO)2Mn: 13a; LnM = (η5-C 5H4Me)(CO)2Mn: 13b) are described. The synthesis o f the alkynyl substituted phosphane compounds LnMP(Ph)m(C ≡ CR )3-m (m = 2: R = Ph, LnM = (η5-C5H5)(C O )2Mn: 20a; LnM = (CO )5 Cr: 20b; R nBu, LnM = (CO)5 Cr: 20c; m = 1: R = Ph, LnM = (η5-C5H5)(CO)2Mn: 22) was also possible. The reaction of (η5-C5H4Me)(CO)2,MnPPh (CH2C ≡CH)2 (13 b) with Co2(CO)8 affords in high yields (η5-C5H4Me)(CO)2MnPPh[(η2 -CH2C ≡ CH )Co2(CO )6]2 (15). All new com pounds have been characterized by analytical and spectroscopic data (IR , 1H -, 13C {1H }-, 31P { 1H } -NMR , MS) and (η5-C5H5)(CO)2MnP(Ph)(CH2C ≡ CH)2 (13a) by X -ray analysis.