Reactions of bis[1,2-bis(dimethylphosphino)ethane]bis(dinitrogen)chromium(0) and -bis(carbonyl)chromium(0) with acids and oxidizing agents. X-Ray crystal structures of trans-CrII(O2CCF3)2(dmpe)2, trans-[CrII(NCR)2(dmpe)2][CF3SO3]2(R = Me or Et), trans-[CrIIICl2(dmpe)2]BPh4·CH2Cl2, trans-[CrI(CO)2(dmpe)2]BPh4, and [Cr0H(CO)2(dmpe)2]BPh4
Abstract
The interaction of trans-Cr(N2)2(dmpe)2[dmpe = 1,2-bis(dimethylphosphino)ethane] with hydrogen chloride gives the eight-co-ordinate chromium(IV) species CrH2Cl2(dmpe)2 whereas CF3CO2H gives trans-Cr(O2CCF3)2(dmpe)2. Protonation by CF3SO3H of trans-CrL2(dmpe)2(L = N2 or C2H4) in MeCN or EtCN gives the chromium(II) octahedral nitrite species trans-[Cr(NCR)2(dmpe)2]2+(R = Me or Et). The electron spin resonance spectra of the latter are attributed to trace impurities of a chromium(I) nitrite species; the main quintet is typical of CrI with four equivalent phosphorus ligands but hyperfine splitting is ascribed to interaction of CH3 groups of MeCN and CH2 groups of EtCN with the 17-electron chromium(I) atom. The interaction of trans-Cr(N2)2(dmpe)2, trans-CrCl2(dmpe)2, or CrH4(dmpe)2 with CH3I or I2 in methanol leads to compounds of general formula trans-[CrIIIX2(dmpe)2]X′(X = Cl or I, X′= I or BPh4). The interaction of cis-Cr(CO)2(dmpe)2 with CF3SO3H followed by treatment with NaBPh4 in MeOH leads to the seven-co-ordinate [CrH(CO)2(dmpe)2]BPh4, while treatment of the dicarbonyl with one equivalent of AgCF3SO3 leads to trans-[Cr(CO)2(dmpe)2]BPh4. X-Ray structures of the following compounds have been determined: trans-Cr(O2CCF3)2(dmpe)2, trans-[Cr(NCR)2(dmpe)2][CF3SO3]2(R = Me or Et), trans-[CrCl2(dmpe)2]BPh4·CH2Cl2, [CrH(CO)2(dmpe)2]BPh4, and trans-[Cr(CO)2(dmpe)2]BPh4.
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