Untersuchungen zum elektronischen einfluß von organoliganden XIV synthese und charakterisierung von organorhodoximen mit ungesättigten C3-liganden
摘要:
[Rh](-) ([Rh]=[Rh(dmgH)(2)(PPh(3))]; dmgH(2) - dimethylgluoxime), prepared by reduction of [Rh(dmgH)(2)(PPh(3))Cl] with NaBH4 in methanolic KOH, reacts with cis/trans-XCH=CHCH(2)X (X=Cl, Br) to give the sigma-allyl complexes cis/trans-[Rh]-CH2CH=CHX (X=Cl: 2a/b; X=Br: 3a/b) and cis/trans-[Rh]-CH2CH=CHOMe (4a/b). Propargyl halides react with [Rh](-) to give [Rh]-CH2C=CH(6) as well as [Rh]-CH=C=CH2 (7a) and [Rh]-C=CMe (8), 7a isomerizes to give 8. In contrast, the dimethyl substituted propargyl chloride HC=CCMe(2)Cl (9) reacts with [Rh](-) to give [Rh]-CH=C=CMe(2) (7b) exclusively. The addition of [Rh](-) on HC=CCH2OH (10a) and on HC=CCH(2)OSiMe(3) (10b) does not proceed regioselectively as the formation of [Rh]-CH=CHCH2OH (11a) and [Rh]-C(CH2OH)=CH2 (11b) show. [Rh](-) reacts with HC=CCH(2)SiMe(3) (13) under addition on the C2 atom and C-Si bond cleavage to give [Rh]-CMe=CH2 (14).All compounds were characterized by H-1-, C-13- and P-31-NMR spectroscopy. With the coupling constant (1)J(Rh-103,P-31) as a measure, the following trend in the trans influence of organo ligands was obtained: alkyl greater than or equal to phenyl similar to vinyl > allyl > allenyl > alkinyl similar to propargyl.