91443-22-0Relevant articles and documents
Binuclear metal carbonyl R-DAB complexes. Conversion of coordinated 1,4-diaza-1,3-butadienes into 3-amino-1-azaallyl monoanions by interaction with [HFe(CO)4]-. Molecular structure of [FeMn(CO)6{(t-Bu)N..-CH..-CHN(H)(t-Bu)}], containing an η3-1-azaallyl moiety bonded to Fe
Keijsper, Jan,Mul, John,Van Koten, Gerard,Vrieze, Kees,Ubbels, Henk C.,Stam, Casper H.
, p. 1732 - 1739 (2008/10/08)
The reaction of [HFe(CO)4]- with [M(CO)3(R-DAB{R1,R2})Br] (R-DAB{R1,R2} = 1,4-disubstituted 1,4-diaza-1,3-butadiene = RN=C(R1)C(R2)=NR, M = Mn, R1 = R2 = H, R = c-Hex, t-Bu, p-tol; M = Mn, R1 = R2 = CH3, R = c-Pr; M = Mn, R1 = H, R2 = CH3, R = i-Pr; M = Re, R1 = R2 = H, R = i-Pr, t-Bu) at 40°C in THF solution yields the novel heterodinuclear species [FeMn(CO)6(R-AAA{R1,R2})] (R-AAA{R1,R2} = 3-R-amino-1-R-azaallyl = RN..-C(R1)..-C(R2)N(H)R). 2 During this reaction, neutral four-electron, σ-N, σ-N′-bonded R-DAB is converted to an eight-electron-bonded, monoanionic 3-R-amino-1-R-azaallyl moiety. The amino substituent containing a new N-H bond coordinates to Mn, while the monoanionic 1-azaallylic moiety is four-electron, η3-bonded to Fe and two-electron, σ-N-bonded to Mn. This is evidenced by an X-ray crystal structure determination of [FeMn(CO)6(t-Bu-AAA)]. Crystals of C16H21FeMnN2O6 are monoclinic of space group P21/c with cell constants a = 16.044 (1) A?, o = 18.220 (2) A?, o = 17.330 (2) A?, β = 129.69 (1)°, and Z = 8.4a A total of 1287 reflections have been used in the refinement, which results in a final R value of 0.042. In the asymmetric unit there are two independent molecules having only slightly different geometries. The Fe-Mn distances of 2.616 (5) and 2.640 (4) A for molecules A and B, respectively, are indicative of a Fe-Mn single bond. The bond lengths within the 3-amino-1-azaallylic N(1)..- C(7)..-(C8)N(2)(H) moiety are N(1)-C(7) = 1.38 A? (mean), C(7)-C(8) = 1.39 A? (mean), and C(8)-N(2) = 1.45 A? (mean), respectively. Formally, the ligand can be described as an eight-electron donor, being σ-N, σ-N′-coordinated to Mn, with bond lengths Mn-N(1) = 2.02 (mean) and Mn-N(2) = 2.12 (mean) A?, and being η3-coordinated to Fe (Fe-C(7) = 2.01 A? (mean), Fe-C(8) = 2.08 A? (mean), and Fe-N(1) = 2.04 (mean)). The metal carbonyl skeleton of the complex consists of five terminal carbonyls with normal M-C(carbonyl) bond lengths and M-C-O bond angles and one semibridging CO group: Fe-C(4) = 1.701 (16) and 1.742 (15) A? for molecules A and B, respectively, with corresponding Mn-C(4) distances of 2.627 (12) and 2.547 (11) A?. The Fe-C(4)-O(4) bond angles are 169.3 (14) and 165.3 (12)° for molecules A and B, respectively. Reaction of [Mn(CO)3(R-DAB)Br] (R = i-Pr, t-Bu) with [DFe(CO)4]- leads to the formation of [Fe Mn(CO)6[RNC(H)C(H)N(D)R)] only, which proves that the transferred deutende (hydride) orginates from the Fe anion reagent. A possible reaction mechanism for the formation of the heterodinuclear R-AAA species is discussed. All complexes have further been characterized by 1H NMR, 13C NMR, IR, and mass spectroscopy.
