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Download file# Influence of the Group 14 Element on the Deprotonation
of OsH(*η*^{5}^{}-C_{5}H_{5})(C⋮CPh)(EPh_{3})(P^{i}Pr_{3}) (E = Si, Ge): Two
Different Organometallic Chemistries

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journal contribution

posted on 2001-10-02, 00:00 authored by Miguel Baya, Miguel A. Esteruelas, Enrique OñateThe complexes OsH(

*η*^{5}-C_{5}H_{5})Cl(EPh_{3})(P^{i}Pr_{3}) (E = Si (**1**), Ge (**2**)) react with lithium phenylacetylide to give the hydride−alkynyl derivatives OsH(*η*^{5}-C_{5}H_{5})(C⋮CPh)(EPh_{3})(P^{i}Pr_{3}) (E = Si (**3**), Ge (**4**)). The structure of**4**has been determined by X-ray diffraction analysis. The distribution of ligands around the osmium atom can be described as a four-legged piano-stool geometry with the monodentate ligands lying in the four-membered face. Treatment of**3**with*n*-butyllithium and the subsequent addition of methanol, methanol-*d*_{4}, and methyl iodide to the resulting solution leads to OsH(*η*^{5}-C_{5}H_{4}SiPh_{3}){CC(H)Ph}(P^{i}Pr_{3}) (**5**), OsH(*η*^{5}-C_{5}H_{4}SiPh_{3}){CC(D)Ph}(P^{i}Pr_{3}) (**5-****), and (***d***6**), respectively. Similarly to**3**, the reaction of the perdeuterated cyclopentadienyl complex OsH(*η*^{5}-C_{5}D_{5})(C⋮CPh)(SiPh_{3})(P^{i}Pr_{3}) (**3-***d***) with**_{5}*n*-butyllithium and methanol gives OsH(*η*^{5}-C_{5}D_{4}SiPh_{3}){CC(H)Ph}(P^{i}Pr_{3}) (**5-***d***). The structure of**_{4}**6**has been also determined by X-ray diffraction analysis. In this case, the distribution of ligands around the osmium atom can be described as a piano-stool geometry with the metalated carbon atom transoid to the phosphine and cisoid to the hydride. Complex**5**reacts with HBF_{4}to give the hydride−carbyne derivative [OsH(*η*^{5}-C_{5}H_{4}SiPh_{3})(⋮CCH_{2}Ph)(P^{i}Pr_{3})]BF_{4}(**7**), which is stable. Initially, the addition of HBF_{4}to diethyl ether solutions of**6**also leads to a hydride−carbyne complex, [OsH(*η*^{5}-C_{5}H_{4}SiPh_{3}){⋮CCH(CH_{3})Ph}(P^{i}Pr_{3})]BF_{4}(**8**). However, in solution, complex**8**evolves into the hydride−allyl compound [OsH(*η*^{5}-C_{5}H_{4}SiPh_{3}){*η*^{3}-CH_{2}C(Ph)CH_{2}}(P^{i}Pr_{3})]BF_{4}(**9**). The structure of**9**has been determined by X-ray diffraction analysis. The distribution of ligands around the osmium atom can be described as a piano-stool geometry, where the allyl ligand occupies two cisoid positions. Treatment of**4**with*n*-butyllithium and the subsequent addition of methanol, methanol-*d*_{4}, and methyl iodide to the resulting solution gives the germyl−vinylidene complexes Os(*η*^{5}-C_{5}H_{5})(GePh_{3}){CC(H)Ph}(P^{i}Pr_{3}) (**10**), Os(*η*^{5}-C_{5}H_{4}D)(GePh_{3}){CC(D)Ph}(P^{i}Pr_{3}) (**10-***d***), and Os(**_{2}*η*^{5}-C_{5}H_{4}CH_{3})(GePh_{3}){CC(CH_{3})Ph}(P^{i}Pr_{3}) (**11**), respectively. The protonation of**10**and**11**with HBF_{4}affords the corresponding carbyne derivatives [Os(*η*^{5}-C_{5}H_{5})(GePh_{3})(⋮CCH_{2}Ph)(P^{i}Pr_{3})]BF_{4}(**12**) and [Os(*η*^{5}-C_{5}H_{4}CH_{3})(GePh_{3}){⋮CCH(CH_{3})Ph}(P^{i}Pr_{3})]BF_{4}(**13**).