75847-53-9Relevant academic research and scientific papers
Organometallic nitrosyl chemistry. 19. Protonation vs. oxidative cleavage of the isoelectronic complexes [(η5-C5H4R)M(LO)2]2 (M = Cr, Mn, or Fe; L = C or N; R = H or Me) by HBF4
Legzdins, Peter,Martin, David T.,Nurse, Charles R.,Wassink, Berend
, p. 1238 - 1244 (2008/10/08)
Treatment of [(η5-C5H5)Fe(CO)2]2 with an equimolar amount of HBF4·OMe2 in CH2Cl2 results in the clean formation of [(η5-C5H5)2Fe 2(CO)4H]BF4 which may be isolated in good yield. In contrast, 2 equiv of the acid are required to consume completely [(η5-C5H5)Cr(NO)2]2, the principal organometallic product being (η5-C5H5)Cr(NO)2BF4. This latter complex is not isolable, but it can be identified spectroscopically and by its derivative chemistry. Some of the workup procedures employed also afford new organometallic nitrosyl complexes of chromium such as [{(η5-C5H5)Cr(NO)2) 2OH]BF4 and (η5-C5H5)Cr(NO)2(OHBPh 3) which have been characterized by conventional methods. Two equivalents of HBF4·OMe2 also consume [(η5-C5H4R)Mn(CO)(NO)]2 (R = H or Me), but a complex mixture of products results. Two well-known (i.e., [(η5-C5H4R)Mn(CO)2(NO)] + and (η5-C5H4R)2Mn 2(NO)3(NO2)) and two novel (i.e., [(η5-C5H4R)3Mn 3-(NO)3NH]+ and [(η5-C5H4R)2Mn 2(NO)2(CO)(NH2)]+) types of manganese nitrosyl complexes are produced in each case, the novel cations being ultimately isolable in low yields as the BF4- and BPh4- salts, respectively. Cyclic voltammograms of [(η5-C5H5)Fe(CO)2]2 and [(η5-C5H5)Cr(NO)2]2 recorded under identical experimental conditions reveal that the chromium dimer undergoes oxidation at a slightly more positive potential. The propensities of the [(η5-C5H4R)M(LO)2]2 (M = Cr, Mn, or Fe; L = C or N; R = H or Me) dimers to undergo protonation or oxidative cleavage when treated with H+ are thus rationalized in terms of the stabilities of the initially formed [(η5-C5H4R)M(LO)2] 2H+ adducts. Interestingly, treatment of [(η5-C5H5)Co(NO)]2 with HBF4·OMe2 in CH2Cl2 results in simple oxidation, the known [(η5-C5H5)Co(NO)]2BF4 complex being obtainable in good yield.
