| Abstract
| - Red-black [HIPTN3N]Cr (1) ([HIPTN3N]3- = [(HIPTNCH2CH2)3N]3- where HIPT = 3,5-(2,4,6-i-Pr3C6H2)2C6H3 =HexaIsoPropylTerphenyl) can be prepared from CrCl3, while green-black [HIPTN3N]Cr(THF) (2) can be preparedfrom CrCl3(THF)3. Reduction of {1|2} (which means either 1 or 2) with potassium graphite in ether at roomtemperature yields [HIPTN3N]CrK (3) as a yellow-orange powder. There is no evidence that dinitrogen is incorporatedinto 1, 2, or 3. Compounds that can be prepared readily from {1|2} include red [HIPTN3N]CrCO (4), blood-red[HIPTN3N]CrNO (6), and purple [HIPTN3N]CrCl (7, upon oxidation of {1|2} with AgCl). The dichroic (purple/green)Cr(VI) nitride, [HIPTN3N]CrN (8) was prepared from Bu4NN3 and 7. X-ray studies have been carried out on 4, 6,and 7, and on two co-crystallized compounds, 7 and [HIPTN3N]CrN3 (65:35) and [HIPTN3N]CrN3 and 8 (50:50).Exposure of a degassed solution of {1|2} to an atmosphere of ammonia does not yield “Cr(NH3)” as a stable andwell-behaved species analogous to Mo(NH3). An attempt to reduce dinitrogen under conditions described for thecatalytic reduction of dinitrogen by [HIPTN3N]Mo compounds with 8 yielded a substoichiometric amount (0.8 equiv)of ammonia, which suggests that some ammonia is formed from the nitride but none is formed from dinitrogen.
- [HIPTN3N]Cr ([HIPTN3N]3- = 3,5-(2,4,6-i-Pr3C6H2)2C6H3) can be prepared readily, as can derivatives such as [HIPTN3N]CrCO (shown without isopropyl groups), [HIPTN3N]CrNO, [HIPTN3N]CrCl, and [HIPTN3N]CrN. No dinitrogen or ammonia complexes could be prepared, and attempts to catalyze the reduction of dinitrogen to ammonia under conditions successful for [HIPTN3N]Mo complexes failed.
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