Albertin Gabriele, Antoniutti Stefano, Bacchi Alessia, Barbera Davide, Bordignon Emilio, Pelizzi Giancarlo, Ugo Paolo
Dipartimento di Chimica and Dipartimento di Chimica Fisica, Università Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia, Italy, and Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Centro CNR di Strutturistica Diffrattometrica, Università di Parma, Viale delle Scienze, 43100 Parma, Italy.
Inorg Chem. 1998 Oct 19;37(21):5602-5610. doi: 10.1021/ic980430e.
Mono- and binuclear aryldiazenido complexes [Fe(ArN(2))(CO)(2)P(2)]BPh(4) (1-4) and {Fe(CO)(2)P(2)}(2)(&mgr;-N(2)Ar-ArN(2))(2) (5-8) [P = P(OEt)(3), PPh(OEt)(2), PPh(2)OEt, P(OPh)(3); Ar = C(6)H(5), 2-CH(3)C(6)H(4), 4-CH(3)C(6)H(4); Ar-Ar = 4,4'-C(6)H(4)-C(6)H(4), 4,4'-(2-CH(3))C(6)H(3)-C(6)H(3)(2-CH(3)), 4,4'-C(6)H(4)-CH(2)-C(6)H(4)] were prepared by allowing hydride species FeH(2)(CO)(2)P(2) to react with an excess of mono- (ArN(2))(BF(4)) or bis-aryldiazonium (N(2)Ar-ArN(2))(BF(4))(2) salts, respectively, at low temperature. A reaction path involving a hydride-aryldiazene intermediate FeH(ArN=NH)(CO)(2)P(2), which, through the loss of H(2), affords the final aryldiazenido complexes 1-8, is proposed. The compounds were characterized by (1)H and (31)P{(1)H} NMR spectroscopy (including (15)N isotopic substitution) and X-ray crystal structure determination. The complex Fe(CO)(2){P(OEt)(3)}(2){&mgr;-4,4'-N(2)(2-CH(3))C(6)H(3)-C(6)H(3)(2-CH(3))N(2)}(2) (5b) crystallizes in the space group P&onemacr; with a = 15.008(4) Å, b = 17.094(5) Å, c = 10.553(3) Å, alpha = 99.56(1) degrees, beta = 102.80(1) degrees, gamma = 65.30(1) degrees, and Z = 1. The structure is centrosymmetric and consists of binuclear cations with the two iron atoms in a quite regular trigonal bipyramidal environment, with the two CO in the equatorial and the two phosphites in the apical position, respectively. Aryldiazenido complexes 1-8 react with strong acids HX (X = Cl, CF(3)SO(3), CF(3)CO(2)) to give the corresponding aryldiazene derivatives, according to the equilibrium Fe(ArN(2))(CO)(2)P(2) + HX right harpoon over left harpoon FeX(ArN=NH)(CO)(2)P(2). Electrochemical studies of both mono- (1-4) and binuclear (5-8) compounds were undertaken, and a mechanism for oxidation and reduction processes is proposed.
单核和双核芳基重氮配合物[Fe(ArN₂)(CO)₂P₂]BPh₄(1 - 4)和{Fe(CO)₂P₂}₂(μ - N₂Ar - ArN₂)₂(5 - 8) [P = P(OEt)₃、PPh(OEt)₂、PPh₂OEt、P(OPh)₃；Ar = C₆H₅、2 - CH₃C₆H₄、4 - CH₃C₆H₄；Ar - Ar = 4,4' - C₆H₄ - C₆H₄、4,4' - (2 - CH₃)C₆H₃ - C₆H₃(2 - CH₃)、4,4' - C₆H₄ - CH₂ - C₆H₄]是通过使氢化物FeH₂(CO)₂P₂分别在低温下与过量的单芳基重氮盐(ArN₂)(BF₄)或双芳基重氮盐(N₂Ar - ArN₂)(BF₄)₂反应制备得到的。提出了一条涉及氢化物 - 芳基二氮烯中间体FeH(ArN = NH)(CO)₂P₂的反应路径，该中间体通过失去H₂得到最终的芳基重氮配合物1 - 8。这些化合物通过¹H和³¹P{(¹H)}核磁共振光谱（包括¹⁵N同位素取代）以及X射线晶体结构测定进行了表征。配合物Fe(CO)₂{P(OEt)₃}₂{μ - 4,4' - N₂(2 - CH₃)C₆H₃ - C₆H₃(2 - CH₃)N₂}₂(5b)结晶于空间群Pī中，a = 15.008(4) Å，b = 17.094(5) Å，c = 10.553(3) Å，α = 99.56(1)°，β = 102.80(1)°，γ = 65.30(1)°，Z = 1。该结构是中心对称的，由双核阳离子组成，两个铁原子处于相当规则的三角双锥环境中，两个CO在赤道平面，两个亚磷酸酯在轴向位置。芳基重氮配合物1 - 8与强酸HX（X = Cl、CF₃SO₃、CF₃CO₂）反应生成相应的芳基二氮烯衍生物，遵循平衡式Fe(ArN₂)(CO)₂P₂ + HX ⇌ FeX(ArN = NH)(CO)₂P₂。对单核（1 - 4）和双核（5 - 8）化合物都进行了电化学研究，并提出了氧化和还原过程的机理。
