Johann Plank

Komplexchemie reaktiver organischer verbindungen: XLVII. Synthese, strukturchemie und druckcarbonylierung von metallcarben-komplexen

Abstract The diazoalkane route has been used for the clean incorporation of diarylcarbene ligands into the organomanganese complexes of composition (η 5 -C 5 H 4 R)Mn(CO) 2− thf ( 1 , R = H; 2 , R = CH 3 ; thf = tetrahydrofuran), whose precursors are labile to substitution. The structure of the complex 4b derived from diazosuberon ( 3b ) and exhibiting a seven-membered carbocyclic carbene ligand has been established by virtue of a single-crystal X-ray diffraction study (monoclinic, space group C 2h 5 - P 2/n; a 1045.6(4), b 789.9(4), c 2153.6(4) pm; β 101.56(3)°; Z = 4; R = 0.075, R w = 0.059). Using the same synthetic approach, the dinuclear compound 4d containing an ω,ω′-biscarbene bridge is accessible in 52% yield starting from 1,4-bis(diazobenzyl)benzene ( 3d ). A methodologically simple procedure for the synthesis of η 2 -ketene complexes emerges from high-pressure carbonylation of the metal carbenes 4b and 5b . The geometry of the benzannelated cycloheptanylidenketene derivative 7b has also been elucidated by X-ray diffraction techniques (monoclinic, space group P 2 1 /n; a 998.9(3), b 1302.3(4), c 1466.6(4) pm; β 91.33(4)°; Z = 4; R = 0.057; R w = 0.062).