Reactions of Trisodium Tetracarbonylmetalates(3-) of Manganese and Rhenium with Broensted Acids and Other Electrophiles. Synthesis of H2M(CO)4- (M=Mn and Re), (CH3)2Re(CO)4-, the First Dialkyl Derivative of a Carbonylmetalate Trianion, and Related Anionic Species

Article abstract of DOI:10.1021/ja00188a029

Treatment of hexamethylphosphoroamide (HMPA) solutions of trisodium tetracarbonylmetalates(3-) of manganese and rhenium with excess liquid ammonia causes precipitation of very thermally stable materials (dec >300 deg C) that are isolated in high yields (85-95percent) and represent the first available pure samples of unsolvated Na3.Infrared and ¹H NMR spectral studies of the protonation of Na3 in HPMA show initial formation of the new monohydrides, HM(CO)4^2-, which are then converted quantitatively to the dihydrides H2M(CO)4^-.The new manganese dihydride, which is isoelectronic with the first known carbonyl hydride, H2Fe(CO)4, and the previously established rhenium complex are isolated in high yields (75-80percent) as the pure salts, , The monohydride dianions, HM(CO)4^2-, also react with Ph3SnCl to provide cis-H(Ph3Sn)M(CO)4^-, which can be isolated as the Et4N⁺ salt for rhenium.The initial successful alkylation reactions of carbonylmetalates(3-) are also reported.Treatment of Na3 with methyl p-toluenesulfonate (MeOTs) in HPMA first provides MeRe(CO)4^2- (identified by IR), which can be protonated or further methylated to give cis-H(Me)Re(CO)4^- or cis-(Me)2Re(CO)4^-, both of which are isolated in good yields (70-80percent) as Ph4E⁺ (E=P, As) salts.These represent the first isolated alkyl derivatives of metal carbonyl trianions.IR, ¹H, ¹³C NMR spectra also confirm that Na3 reacts with 1,4-butaneditosylate to provide solutions of the somewhat thermally unstable rhenacyclopentane CH2CH2CH2CH2Re(CO)4^-, the initial example of an anionic 18-electron metallacycloalkane.Infrared, ¹H, and ¹³C NMR spectral data have been obtained for many of these compounds and are compared with those of analogous previously known iron and osmium species.