Protonation of the acyclic tetraaza metallocomplex of gold(III) [Au(C9H19N4)]2+ in aqueous solution. Synthesis and crystal and molecular structure of [Au(C9H20N4)](H5O2)(ClO4)4

Protonation equilibrium has been studied for the acyclic gold(III) tetraaza metallocomplex [AuB]²⁺ [B = N, N′-bis(2-aminoethyl)-2,4-pentanediiminato(1−)] in aqueous solution. The synthetic procedure is described. The crystal and molecular structure of the protonated form of the [AuHB](H₅O₂)(ClO₄)₄ complex has been determined. Monoclinic crystals with unit cell dimensions a = 11.964(2) Å, b = 13.789(3) Å, c = 15.496(3) Å, β = 109.00(3)°, V = 2417.1(8) ų, Z = 4, ρcalc = 2.243 g/cm³, space group P2₁/n. The structure is built of nearly planar [Au(C₉H₂₀N₄)]³⁺ complex cations, (H₅O₂)⁺ cations, and [ClO₄]⁻ anions. The gold atom coordinates four nitrogen atoms of the ligand, forming a square plane. The six-membered chelate ring of the ligand is protonated at the central β-carbon atom and contains imine C=N bonds. The oxygen atoms of the perchlorate ions are hydrogen bonded to the (H₅O₂)⁺ dihydroxonium ion and to the nitrogen atoms of the NH₂ groups of the [AuHB]³⁺ cation. Original Russian Text Copyright ? 2005 by V. A. Afanasieva, L. A. Glinskaya, R. F. Klevtsova, and I. V. Mironov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 5, pp. 909–915, September–October, 2005.     

甲醇/水混合团簇的多光子电离质谱研究

利用多光子电离技术结合飞行时间质谱仪对甲醇/水混合团簇进行了研究.在脉冲激光波长为355 nm条件下观测到团簇离子.主要的电离产物为质子化的(CH3OH)n(H2O)H+(n=l-13)混合团簇离子与(CH3OH)nH+团簇离子,经分析(CH3OH)1o(H2O) H+和(CH3OH)3H+为幻数结构.甲醇水混合团簇电离后团簇离子发生内部质子化转移反应是形成质子化团簇离子的主要原因.不同尺寸团簇离子信号强度随电离激光光强变化的光强指数曲线显示,团簇均发生四光子电离过程.     

Synthesis and Crystal Structure of a Two-dimensional Sil-ver(I)-Iron(III) Heteronuclear Coordination Polymer:{[Ag_4Fe_2(SCN)_(12)(H_2O)_2][(inaH)_2(H_2O)_2]}_n

Introduction Molecules containing different kinds of metal ions play an important role in molecular magnetism.1-3 So considerable attention has been paid to synthesizing heteronuclear complexes.1-4 As a potential bridging ligand, thiocyanate can coordinate to a harder metal center and softer ones with N and S atoms respectively. The complexes of thiocyanate and representative hard acidFe(III) ions usually have a six-coordinate octahe-dral structure such as [Fe(SCN)n]3-n and (Bu4N)4[Ag2-F…     

四吡啶基卟啉质子化结构变化的理论研究

为考察m-吡啶基对质子化卟啉结构的影响,用半经验的AM1MO方法,并进行合理的对称性限制,计算了一类重要的卟啉衍生物---四吡啶基卟啉(TPyPH~2)及其质子化二酸(TP~yPH~4^2^+)的构型。通过结构分析,电荷布居分析和前沿轨道分析,讨论了质子化过程中的构型变化以及这种变化对分子堆积可能带来的影响。     

氨与甲醇混合团簇的多光子电离质谱及从头算研究

用多光子电离技术结合飞行时间质谱仪对氨与甲醇混合团簇进行了研究.在脉冲激光波长分别为266nm,355nm和532nm条件下,仅在355nm作用下观测到团簇离子.主要的电离产物为质子化的(CH3OH)n(NH3)mH (n=0~6,m=0~4)混合团簇离子,且各个序列的离子强度随m的增大而减小.经分析,氨与甲醇混合团簇电离后团簇离子发生内部质子化转移反应是形成质子化团簇离子的主要原因.不同尺寸团簇离子信号强度随电离激光光强变化的光强指数曲线显示,团簇均发生四光子电离过程.应用量化计算,构造了质量数较小的几个团簇离子的可能的空间几何构型,发现二元团簇离子(CH3OH)n(NH3)mH 是以NH4 作为内核离子,再通过氢键与其它分子组合而构成团簇离子.     

Theoretical study of isomerism in protonated forms of N2O,NPO, and P2O

The geometric parameters of the isomers HN₂O⁺, HPNO⁺, and HP₂O⁺ were calculated by the nonempirical SCF/3-21G* method and their relative energies were determined with consideration of the electronic correlation in the MP3/DEHD + PS approximation. According to the calculations, protonation of N₂O, PNO, and P₂O molecules should preferably take place at the oxygen atom. Isomers with a quasilinear NNO and PNO backbone are most advantageous in HN₂O⁺ and HPNO⁺, and cyclic isomers are 60 and 30 kcal/mole less stable, respectively. On the contrary, the cyclic form is more stable for HPO ₂ ⁺ (by 10 kcal/mole). The bond at the attacked atom usually weakens (breaks) and the neighboring (opposite) bonds are strengthened in protonation. Protonation of P₂O stabilizes the cyclic isomer by 15 kcal/mole more strongly than the "open" isomer, resulting in inversion of their position on the energy scale. In the case of N₂O and PNO, the relative position of the cyclic and basic isomers virtually does not change, but the linear NPO isomer is destabliized. The stability of the cyclic isomers in comparison to the "open" isomers increases on substitution of N atoms by P atoms in both molecules of N₂O, PNO, and P₂O and in their ions HN₂O⁺, HPNO⁺, and HP₂O⁺. This tendency probably holds in subsequent transition to As and Sb atoms.Institute of New Chemical Problems, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 126–134, January, 1992.