Chemistry of Highly Electrophilic Binuclear Cations. 4. Synthesis and Reactivity of the Dinuclear Radicals [M2(5
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- 作者：M. Angeles Alvarez ; Yvonne Anaya ; M. Esther Garcí ; a ; and Miguel A. Ruiz
- 刊名：Organometallics
- 出版年：2004
- 出版时间：August 2, 2004
- 年：2004
- 卷：23
- 期：16
- 页码：3950 - 3962
- 全文大小：203K
- 年卷期：v.23,no.16(August 2, 2004)
- ISSN：1520-6041
文摘
Oxidation of the compounds [M2Cp2(CO)4(
-L2)] (M = Mo, W; Cp = 
chars/eta.gif" BORDER=0 >5-C5H5; L2 =Ph2PCH2PPh2 (dppm), Me2PCH2PMe2 (dmpm), (EtO)2POP(OEt)2 (tedip)) with [FeCp2](BAr'4)(Ar' = 3,5-C6H3(CF3)2) gives the corresponding tetracarbonyl radicals [M2Cp2(-CO)2(CO)2(-L2)](BAr'4). The stability of these paramagnetic complexes depends on the ligand and themetal. Thus, the dmpm complexes are stable in solution for reasonable periods of time,whereas the dppm complexes experience spontaneous decarbonylation at room temperatureto give the radicals [Mo2Cp2(-CO)2(-dppm)](BAr'4) and [W2Cp2(-CO)(CO)2(-dppm)](BAr'4).The tedip-bridged derivatives are the most unstable radicals, with the ditungsten cationexperiencing rapid hydrogen atom capture to give the hydride complex [W2Cp2(-H)(CO)4(-tedip)](BAr'4). The complexes [M2Cp2(-CO)2(CO)2(-L2)](BAr'4) react with NO to give thebinuclear nitrosyl derivatives [M2Cp2(CO)4(NO)(-L2)](BAr'4) (M = Mo, W; L2 = dmpm,tedip) and [Mo2Cp2(-CO)(CO)2(NO)(-dmpm)](BAr'4). Some mononuclear products such as[MCp(CO)2(OPMe2CH2PMe2)](BAr'4) were identified in these reaction mixtures. The diphosphine-bridged dimolybdenum radicals are reactive toward small molecules containing H-Ebonds (with E = N, P, O, S) under mild conditions. Thus, reaction of [Mo2Cp2(-CO)2(CO)2(-dppm)](BAr'4) with water at room temperature yields the hydroxo complexes [Mo2Cp2(-OH)(CO)2(-dppm)](BAr'4) and [Mo2Cp2(-H)(-OH)(CO)2(-dppm)](BAr'4)(OH), while reactions with HSPh give mixtures of cis-[Mo2Cp2(-SPh)(-CO)(CO)2(-L2)](BAr'4), cis-[Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4), and cis-[Mo2Cp2(-H)(-SPh)(CO)2(-dppm)](BAr'4)(SPh), withtheir relative amounts depending on the diphosphine and experimental conditions. Thetricarbonyls cis-[Mo2Cp2(-SPh)(-CO)(CO)2(-L2)](BAr'4) rearrange to the correspondingtrans isomers upon exposure to UV-visible light, and the dppm derivative even experiencesa reversible decarbonylation to give trans-[Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4). cis- andtrans-dicarbonyls [Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4) are protonated by HBF4·OEt2with retention of geometry to yield the corresponding hydride derivatives cis- and trans-[Mo2Cp2(-H)(-SPh)(CO)2(-dppm)](BAr'4)(BF4). Deprotonation of the latter with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is not reversible, as it gives in both cases the cis isomer,which suggest the operation of a reduction/dehydrogenation reaction pathway. The structuresof the new complexes are analyzed on the basis of the corresponding IR and NMR (1H, 31P,13C) data, and the reaction pathways operative in the reactions with H2O and HSPh arediscussed on the basis of the available data and some additional experiments.
-L2)] (M = Mo, W; Cp = chars/eta.gif" BORDER=0 >5-C5H5; L2 =Ph2PCH2PPh2 (dppm), Me2PCH2PMe2 (dmpm), (EtO)2POP(OEt)2 (tedip)) with [FeCp2](BAr'4)(Ar' = 3,5-C6H3(CF3)2) gives the corresponding tetracarbonyl radicals [M2Cp2(-CO)2(CO)2(-L2)](BAr'4). The stability of these paramagnetic complexes depends on the ligand and themetal. Thus, the dmpm complexes are stable in solution for reasonable periods of time,whereas the dppm complexes experience spontaneous decarbonylation at room temperatureto give the radicals [Mo2Cp2(-CO)2(-dppm)](BAr'4) and [W2Cp2(-CO)(CO)2(-dppm)](BAr'4).The tedip-bridged derivatives are the most unstable radicals, with the ditungsten cationexperiencing rapid hydrogen atom capture to give the hydride complex [W2Cp2(-H)(CO)4(-tedip)](BAr'4). The complexes [M2Cp2(-CO)2(CO)2(-L2)](BAr'4) react with NO to give thebinuclear nitrosyl derivatives [M2Cp2(CO)4(NO)(-L2)](BAr'4) (M = Mo, W; L2 = dmpm,tedip) and [Mo2Cp2(-CO)(CO)2(NO)(-dmpm)](BAr'4). Some mononuclear products such as[MCp(CO)2(OPMe2CH2PMe2)](BAr'4) were identified in these reaction mixtures. The diphosphine-bridged dimolybdenum radicals are reactive toward small molecules containing H-Ebonds (with E = N, P, O, S) under mild conditions. Thus, reaction of [Mo2Cp2(-CO)2(CO)2(-dppm)](BAr'4) with water at room temperature yields the hydroxo complexes [Mo2Cp2(-OH)(CO)2(-dppm)](BAr'4) and [Mo2Cp2(-H)(-OH)(CO)2(-dppm)](BAr'4)(OH), while reactions with HSPh give mixtures of cis-[Mo2Cp2(-SPh)(-CO)(CO)2(-L2)](BAr'4), cis-[Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4), and cis-[Mo2Cp2(-H)(-SPh)(CO)2(-dppm)](BAr'4)(SPh), withtheir relative amounts depending on the diphosphine and experimental conditions. Thetricarbonyls cis-[Mo2Cp2(-SPh)(-CO)(CO)2(-L2)](BAr'4) rearrange to the correspondingtrans isomers upon exposure to UV-visible light, and the dppm derivative even experiencesa reversible decarbonylation to give trans-[Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4). cis- andtrans-dicarbonyls [Mo2Cp2(-SPh)(CO)2(-dppm)](BAr'4) are protonated by HBF4·OEt2with retention of geometry to yield the corresponding hydride derivatives cis- and trans-[Mo2Cp2(-H)(-SPh)(CO)2(-dppm)](BAr'4)(BF4). Deprotonation of the latter with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is not reversible, as it gives in both cases the cis isomer,which suggest the operation of a reduction/dehydrogenation reaction pathway. The structuresof the new complexes are analyzed on the basis of the corresponding IR and NMR (1H, 31P,13C) data, and the reaction pathways operative in the reactions with H2O and HSPh arediscussed on the basis of the available data and some additional experiments.