91178-29-9Relevant academic research and scientific papers
Synthesis from diamines of mono- and dinuclear cyclopentadienyliron dicarbonyl carbamoyl compounds. Crystal and molecular structure of (μ-CONH(CH2)2NHCO)[CpFe(CO)2]2
Lindsay, Alan J.,Kim, Sangsoo,Jacobson, Robert A.,Angelici, Robert J.
, p. 1523 - 1530 (2008/10/08)
The cationic complex [CpFe(CO)3]PF6 exhibits three types of reactivity toward diamines. It reacts with the unsymmetrical primary diamine H2NCH2CMe2NH2 to give the mononuclear cationic carbamoyl complex [CpFe(CO)2(CONHCH2CMe2NH3)]PF 6 (1); spectroscopic studies indicate relatively strong intermolecular hydrogen bonding between the carbamoyl oxygen and an NH3+ group. Complex 1 is readily deprotonated to yield its neutral analogue CpFe(CO)2(CONHCH2CMe2NH2) (2) that can be further deprotonated in the presence of [CpFe(CO)3]PF6 to form the first reported dinuclear dicarbamoyl-bridged complex (μ-CONHCH2CMe2NHCO)[CpFe(CO)2]2 (3). In addition, [CpFe(CO)3]PF6 reacts with the unsymmetrical primary/tertiary diamine H2N(CH2)2NMe2 and with H2N(CH2)2OH to form exclusively CpFe(CO)2-(CONH(CH2)2NMe2) (4) and CpFe(CO)2(CONH(CH2)2OH) (5), respectively. Finally, [CpFe(CO)3]PF6 reacts with symmetrical primary and secondary diamines such as RHN(CH2)xNHR (R = H, x = 2, 3; R = Me, x = 2) and the cyclic diamine piperazine HN(CH2CH2)2NH to yield exclusively the dinuclear dicarbamoyl-bridged complexes (μ-CONR(CH2)xNRCO)[CpFe(CO)2]2, (R = H, x = 2 (6); R = H, x = 3 (7); R = Me, x = 2 (8)) and (μ-CON(CH2CH2)2NCO)[CpFe(CO) 2]2 (9). The molecular structure of complex 6 was determined by X-ray diffraction. The crystals are triclinic of space group P1 with two crystallographically independent molecules per unit cell, each having an inversion center, and with cell constants of α = 9.504 (7) A?, b = 8.435 (5) A?, c = 12.989 (9) A?, α = 101.20 (5)°, β = 104.80 (5)°, and γ = 100.49 (5)°. The structure was refined to R = 0.043 and Rw = 0.047 for 1485 independent observed reflections having I ≥ 3.0σ(I). The dimensions of the two crystallographically independent molecules do not differ significantly; the average Fe-C (carbamoyl) distance of 1.99 A? is significantly longer than the average Fe-C(CO) distance of 1.76 A?. The overall geometry of the structure shows the metal centers to be in a transoid orientation about the bridging ligand as dictated by the inversion center, and the central part of the structure adopts a gauche-trans-gauche conformation. Each molecule is connected through weak hydrogen bonds to two others.
