Abou-Hamdan Amira, Roodt Andreas, Merbach André E.
Institut de Chimie Minérale et Analytique, Université de Lausanne, Bâtiment de Chimie (BCH), Lausanne CH-1015, Switzerland, and Department of Chemistry, University of the Orange Free State, Bloemfontein 9300, South Africa.
Inorg Chem. 1998 Mar 23;37(6):1278-1288. doi: 10.1021/ic971239s.
A range of complexes with general formula MO(X)(CN)(4)()(-) of W(IV), Mo(IV), Re(V), Tc(V), and Os(VI) were prepared and characterized by (13)C, (15)N, (17)O, and (99)Tc NMR, utilizing (13)C- and (15)N-enriched cyano complexes. A correlation between M-O and M-CN bond strength from X-ray crystallographic data and |(1)J((183)W-(13)C)| coupling is reported. The cyanide (HCN/CN(-)) exchange kinetics on the trans-dioxotetracyanometalate complexes and protonated/substituted (MO(X)(CN)(4)()(-)) forms thereof were studied in aqueous medium. The dioxotetracyano complexes show a trend of reactivity M(IV) > M(V) >M(VI), which is in agreement with the increase in M-L bond strength (L = O(2)(-) or CN(-)) and a dissociative activation for the cyanide and the oxygen exchange in these complexes. Rate constants (X, k(Xc)) in s(-)(1) at 298 K for the MO(X)(CN)(4)()(-) complexes are as follows for Mo(IV): O(2)(-), >0.4; OH(-), (1.7 +/- 0.1) x 10(-)(2); H(2)O, (1.5 +/- 0.1) x 10(-)(2); CN(-), (9.6 +/- 0.8) x 10(-)(3). For W(IV): O(2)(-), (4.4 +/- 0.4) x 10(-)(3); OH(-), (9.6 +/- 0.9) x 10(-)(5); H(2)O, (1.1 +/- 0.1) x 10(-)(4); CN(-), (1.1 +/- 0.1) x 10(-)(2); N(3)(-), (3.1 +/- 0.2) x 10(-)(4); F(-), (4.8 +/- 0.1) x 10(-)(5). For Tc(V): O(2)(-), (4.8 +/- 0.4) x 10(-)(3); H(2)O, <4 x 10(-)(5); NCS(-), <4 x 10(-)(5). For Re(V): O(2)(-), (3.6 +/- 0.3) x 10(-)(6) and (1.2 +/- 0.1) x 10(-)(4) for CN(-) and HCN, respectively; OH(2), <4 x 10(-)(8). For Os(VI): O(2)(-), <4 x 10(-)(9) and (1.2 +/- 0.1) x 10(-)(4) for CN(-) and HCN, respectively. The cyanide exchange kinetics were correlated with previously determined proton and oxygen exchange, spanning a kinetic domain of more than 12 orders of magnitude for the five metal centers studied.
制备了一系列通式为MO(X)(CN)(4)()(-)的W(IV)、Mo(IV)、Re(V)、Tc(V)和Os(VI)配合物，并利用富含(13)C和(15)N的氰基配合物通过(13)C、(15)N、(17)O和(99)Tc NMR进行了表征。报道了X射线晶体学数据中M - O和M - CN键强度与|(1)J((183)W-(13)C)|耦合之间的相关性。研究了反式-二氧代四氰基金属配合物及其质子化/取代形式(MO(X)(CN)(4)()(-))在水介质中的氰化物(HCN/CN(-))交换动力学。二氧代四氰基配合物呈现出反应活性顺序为M(IV) > M(V) > M(VI)，这与M - L键强度(L = O(2)(-)或CN(-))的增加以及这些配合物中氰化物和氧交换的解离活化相一致。MO(X)(CN)(4)()(-)配合物在298 K时的速率常数(X, k(Xc))以s(-)(1)为单位，对于Mo(IV)如下：O(2)(-)，>0.4；OH(-)，(1.7 ± 0.1)×10(-)(2)；H(2)O，(1.5 ± 0.1)×10(-)(2)；CN(-)，(9.6 ± 0.8)×10(-)(3)。对于W(IV)：O(2)(-)，(4.4 ± 0.4)×10(-)(3)；OH(-)，(9.6 ± 0.9)×10(-)(5)；H(2)O，(1.1 ± 0.1)×10(-)(4)；CN(-)，(1.1 ± 0.1)×10(-)(2)；N(3)(-)，(3.1 ± 0.2)×10(-)(4)；F(-)，(4.8 ± 0.1)×10(-)(5)。对于Tc(V)：O(2)(-)，(4.8 ± 0.4)×10(-)(3)；H(2)O，<4×10(-)(5)；NCS(-)，<4×10(-)(5)。对于Re(V)：O(2)(-)，(3.6 ± 0.3)×10(-)(6)，对于CN(-)和HCN分别为(1.2 ± 0.1)×10(-)(4)；OH(2)，<4×10(-)(8)。对于Os(VI)：O(2)(-)，<4×10(-)(9)，对于CN(-)和HCN分别为(1.2 ± 0.1)×10(-)(4)。氰化物交换动力学与先前测定的质子和氧交换相关，在所研究的五个金属中心中跨越了超过12个数量级的动力学范围。
