Formation and Structure of Heptacoordinate Dihalogeno Carbene-C,O Chelate Complexes and Dihalogeno Carbene-C,O Chelate Phosphine Complexes of Molybdenum(II) and Tungsten(II): A New Class

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• 作者：Rü ; diger Stumpf ; Monika Jaeger ; and Helmut Fischer
• 刊名：Organometallics
• 出版年：2001
• 出版时间：September 17, 2001
• 年：2001
• 卷：20
• 期：19
• 页码：4040 - 4048
• 全文大小：115K
• 年卷期：v.20,no.19(September 17, 2001)
• ISSN：1520-6041

文摘

The carbene-C,O chelate carbonyl tungsten(0) complex [(CO)₄W=C(OMe)C₆H₄OMe-o] (1)reacts with phosphines by opening of the chelate ring to form [(CO)₄(PR₃)W=C(OMe)C₆H₄OMe-o] (R = Me (5), ⁿBu (6), Ph (7), Cy (8)). Treatment of 5 and 6 with SnX₄ affords byoxidative decarbonylation, depending on R and X, either one or two isomers of the carbene-C,O chelate dicarbonyl phosphine tungsten(II) complexes [X₂(CO)₂(PR₃)W=C(OMe)C₆H₄OMe-o] (R = Me, X = Cl (9a), Br (9b), I (9c-A/9c-B); R = ⁿBu, X = Cl (10a), Br (10b-A/10b-B),I (10c)). The isomers do not interconvert. In the corresponding reaction of 7 with SnBr₄instead of a carbene-C,O chelate dicarbonyl phosphine tungsten(II) complex the carbene-C,O chelate tricarbonyl tungsten(II) complex [Br₂(CO)₃W=C(OMe)C₆H₄OMe-o] (3b) is formed.When 8 is treated with SnBr₄, the formation of a carbene-C,O chelate phosphine tungsten(II) complex cannot be detected any more. Like the o-OMe tungsten(0) complexes 5 and 6the p-OMe tungsten(0) complex [(CO)₄(PⁿBu₃)W=C(OMe)C₆H₄OMe-p] (11) and the ring-unsubstituted complex [(CO)₄(PⁿBu₃)W=C(OMe)Ph] (13) react with SnBr₄ by oxidativedecarbonylation and formation of W(II) complexes, [Br₂(CO)₃(PⁿBu₃)W=C(OMe)R'] (R' =C₆H₄OMe-p, Ph) (two isomers each). Dicarbonyl carbene-C,O chelate trimethylphosphinemetal(II) complexes [X₂(CO)₂(PMe₃)M=C(OMe)C₆H₄OMe-o] (M = Mo, W; X = Cl, Br) arealso accessible by substitution of PMe₃ for a CO ligand in [X₂(CO)₃M=C(OMe)C₆H₄OMe-o].However, when PMe₃ is replaced by the bulkier PPh₃ in the reaction with [Br₂(CO)₃M=C(OMe)C₆H₄OMe-o], instead of substitution, the opening of the chelate ring is observed.