Aminomethylation of Aminoferrocene, [(η⁵-C₅H₅)Fe(η⁵-C₅H₄NH₂)], and (Anilino)chromiumtricarbonyl, [(η⁶-C₆H₅NH₂)Cr(CO)₃], by O-Triethylsilyl-hemiaminal, (Et₃SiOCH₂NMe₂): The Role of Disparate Organometallic Electronic Effects in Modifying Product Outcomes

Abstract

The room-temperature reaction of O-triethylsilyl-hemiaminal, Et 3 SiOCH 2 NMe 2 , (1) with primary amines containing organometallic electron-donating ferrocenyl or electron-withdrawing arenechromiumtricarbonyl groups, Fc−NH 2 {Fc = [(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )] (2) and [(η 6 -C 6 H 5 NH 2 )Cr(CO) 3 ] (3), respectively}, led to separate and distinctive chemistry. The reaction between 1 and 2 initially produced the transient triamine FcN(CH 2 NMe 2 ) 2 (4), which transformed upon workup into 1,3,5-triferrocenyl-1,3,5-hexahydrotriazine (5). The reaction between 1 and 3 led to the isolation of the diamine [(C 6 H 5 NHCH 2 NMe 2 )Cr(CO) 3 ] (7) as the only product. The complexes 5 and 7 are stable materials and were readily characterized spectroscopically and structurally. The labile ferrocenyltriamine 4 was readily trapped by complexation with Mo(CO) 4 {presented as [(norbornadiene)Mo(CO) 4 ]} to form [FcN(CH 2 (NMe 2 ) 2 ]Mo(CO) 4 (6), coordinating the Mo atom in a bidentate manner via the terminal NMe 2 groups. The Me 2 NCH 2 group in 7 readily exchanged upon reaction with either Et 2 NH or Et 2 NCH 2 NEt 2 to yield the diamine [(η 6 -C 6 H 5 NHCH 2 NEt 2 )Cr(CO) 3 ] (8). The initial cyclic voltammetric analysis exhibited oxidation of each separate metal center in both 5 and 6.