U(IV)/Ln(III) unexpected mixed site in polymetallic oxalato complexes. Part I. Substitution of Ln(III) for U(IV) from the new oxalate (NH4)2U2(C2O4)5·0.7H2O
hexagonal tunnels running down the [001] direction. Starting from the uranium (IV) compound A2U2(C2O4)5·0.7H2O with A=NH4+ (1), the mixed U(IV)/Ln(III) oxalates are obtained by partial substitution of U(IV) by Ln(III) in a ten-coordinated site, the charge deficit being compensated by intercalation of supplementary monovalent ions within the tunnels. The distortion of the arrangement in the [001] direction
一种新的草酸铀(IV)铵(NH 4)2 U 2(C 2 O 4)5 ·0.7H 2 O(1)和三种混合铀(IV)-镧系元素(III)草酸酯,(N 2 H 5)2.6 U 1.4 M 0.6(C 2 O 4)5 · x H 2 O(M = Nd(2)和M = Sm(3)),Na 2.56 U 1.44 Nd 0.56(C制备了2 O 4)5 ·7.6H 2 O(4)和Na 3 UCe(C 2 O 4)5 ·10.4H 2 O(5)。化合物的晶体结构1,4和5已经通过单晶X射线衍射来确定。通过直接方法和傅立叶差分技术来解析晶体结构,并针对所有唯一反射,在F 2的基础上通过最小二乘法对晶体结构进行细化。化合物2和3与1同型。晶体学数据:1,六角形,空间群P 6 3 / mmc的,一个= 19.177(3),C ^ = 12.728(4),Ž = 6,- [R 1 = 0.0575 52个参数与1360个反射与我⩾2
Phosphite complexes of tin(II)
作者:C. G. Davies、J. D. Donaldson、W. B. Simpson
DOI:10.1039/j19690000417
日期:——
the presence of the species, SnHPO3, Sn(HPO3)22–, and Sn(HPO3)34– in solutions of tin(II) phosphite in the pH range 4·5–8. The solid complexes M4Sn(HPO3)3(M = NH4, Na, K, Rb, or Cs) have been prepared. The Mössbauer and i.r. spectra of the complexes are consistent with the presence of a pyramidal triphosphitostannate(II) ion in these materials. The thermal decomposition of the complexes is discussed
Gas-phase chemistry of transition metal-imido and -nitrene ion complexes. Oxidative addition of nitrogen-hydrogen bonds in ammonia and transfer of NH from a metal center to an alkene
作者:Steven W. Buckner、James R. Gord、Ben S. Freiser
DOI:10.1021/ja00228a002
日期:1988.9
CrNH/sub 3//sup +/, as do all group 6-11 atomic metal ions investigated. However, excited-state Cr/sup +/ reacts with NH/sub 3/ via bond-insertion reactions to form CrNH/sub2//sup +/ and CrNH/sup +/. An unidentified metastable electronic state of Cr/sup +/, produced by direct laser desorption of chromium foil, reacts with much higher efficiency than does kinetically excited Cr/sup +/. FeO/sup +/ reacts
Mechanistic Information from Pressure Acceleration of Hydride Formation via Proton Binding to a Cobalt(I) Macrocycle
作者:Etsuko Fujita、James F. Wishart、Rudi van Eldik
DOI:10.1021/ic011109q
日期:2002.3.1
occurring via proton transfer. Whereas the corresponding volumes of activation (DeltaV) are rather small and negative for all acids (protondonors) with pK(a) values below 8.5, significantly larger negative activation volumes are found for weaker acids (pK(a) > 9.5) containing OH groups as protondonors. In the latter case, the observed DeltaV for these protonationreactions show a correlation with the reaction
Gas phase basicities and relative proton affinities of compounds between water and ammonia from pulsed ion cyclotron resonance thermal equilibriums measurements
作者:J. F. Wolf、R. H. Staley、I. Koppel、M. Taagepera、R. T. McIver、J. L. Beauchamp、R. W. Taft
DOI:10.1021/ja00458a032
日期:1977.8
indicate that protonation is thermodynamically favored in the gas phase at the carbonyl oxygen of the latter. Large effects of polar electronegative substituents have been observed for various oxygen and nitrogen bases. An evaluation of entropy effects in gas phase protontransferequilibria shows such effects to bemore » generally small for simple bases and approximately equal to entropy effects expected
用于精确测定质子转移平衡常数的脉冲离子回旋共振方法已应用于 46 种碳、氮、氧、磷、硫、砷和硒碱,重复重叠序列,获得水和氨的相对质子亲和力. 在可能进行比较的情况下,结果通常与高压质谱法获得的结果一致。结果为分子结构对基础强度的内在影响提供了重要的新见解。说明了这些结果在导出其他气态离子热化学数据中的应用。特别是,甲基取代基对质子亲和力的影响已被广泛评估,并解释了与 n 碱共轭酸的均裂键解离能的相应影响和取代甲基阳离子的氢化物亲和力的比较。正烷基取代基对水和醇与羧酸及其酯的质子亲和力影响的比较表明,质子化在气相中在后者的羰基氧处是热力学有利的。对于各种氧和氮碱,已经观察到极性电负性取代基的巨大影响。对气相质子转移平衡中的熵效应的评估表明,这种效应对于简单的碱基通常较小,大约等于分子旋转对称数变化时预期的熵效应。最后,目前的结果为评估绝对质子亲和力和相对离子溶剂化能提供了基础。« 更少