98689-89-5Relevant academic research and scientific papers
Synthesis and structure of a chelated manganese carbene-alkene complex
McGeary,Tonker,Templeton
, p. 2102 - 2106 (1985)
Reaction of (η5-C5H4(CH3))Mn(CO) 2(≡CC6H5)][BCl4] with excess allylamine generated (η5-C5H4(CH3))Mn(CO) 2[C(C6H5)(NHCH2CH=CH2)], 1, as a 2.8:1.0 mixture of isomers. Isomers of 1 exist as a consequence of restricted carbene carbon-nitrogen bond rotation. High-temperature NMR studies on (η5-C5H4(CH3))Mn(CO) 2[C(C6H5)(N(CH3)2)] establish a minimum barrier to rotation around the C-N bond of 21 kcal/mol for this complex. Low-temperature photolysis of 1 resulted in the formation of (η5-C5H4(CH3))Mn(CO)[C(C 6H5)(η2-NHCH2CH=CH 2)], 2. Infrared and 1H and 13C NMR data are reported for both 1 and 2. The X-ray crystal structure of 2 shows a roughly octahedral arrangement of the ligands in which the carbene is cis and approximately parallel to the olefin. The compound crystallizes in the space group P21/c with four molecules per unit cell (a = 7.936 (2) A?, b = 14.593 (5) A?, c = 12.569 (5) A?, β = 99.08 (3)°, V = 1437.4 A?3, ρ(calcd) = 1.420 g/cm3). Full-matrix least-squares refinement of 121 parameters using 866 data with I ≥ 2σ(I) converged with R = 0.074 and R2 = 0.052. The geometry of this first-row transition-metal carbene-alkene complex is compared to the geometry reported by Casey and co-workers for the analogous chelating carbene-alkene linkage in a tungsten derivative, (CO)4W[C(tolyl)(η2-NHCH2CH=CH 2)].
