Nucleophilic substitution reactions at planar four-co-ordinate monoanionic platinum(II) complexes
作者:Bruno Pitteri、Lucio Cattalini、Gavino Chessa、Giampaolo Marangoni、Nicoletta Stevanato、Martin L. Tobe
DOI:10.1039/dt9910003049
日期:——
The kinetics of displacement of chloride from complex anions of the type [Pt(4R-pydca)Cl]–(pydca = pyridine-2,6-dicarboxylate; R = H, Cl or OMe) by a number of anionic and neutral nucleophiles have been studied in aqueous solution, at 25.0 °C, I= 0.50 mol dm–3(LiClO4). Apart from the reactions with OH–, the reactivities of the substrates are not greatly sensitive to the nature of the substituent in
从类型的配阴离子[PT(4R-pydca)CL]氯化物的位移的动力学-(pydca =吡啶-2,6-二羧酸二; R = H,Cl或OME)通过许多阴离子和中性亲核试剂的有在25.0°C的水溶液中研究了I = 0.50 mol dm –3(LiClO 4)。除了与OH反应- ,基片的反应性并不在4位上的取代基的性质极大地敏感。阴离子亲核试剂的反应性可比具有相似n 0 pt值的中性亲核试剂少两个数量级。与OH反应的速率定律–形式为-dln [substrate] / d t= k s + k 3 [OH – ] 2,其中k s是在所有取代反应中观察到的溶剂分解途径的一级速率常数,其中k 3对齿状配体中氮的碱性敏感。
Monomeric and polymeric copper and zinc tripyrrins
作者:Martin Bröring、Serguei Prikhodovski、Carsten D. Brandt、Esther Cónsul Tejero、Silke Köhler
DOI:10.1039/b613800d
日期:——
Neutral transition metal complexes of different α,ω-dimethyltripyrrins TrpyMX with M = CuII and ZnII have been prepared with a variety of anionic halogeno and pseudohalogeno ligands X, and have been studied with respect to coordination modes and structural distortion. Only four- and five-coordinate species have been observed throughout the series. All four-coordinate species display unstrained, but distorted tetrahedral or strained and distorted square-planar coordination environments for zinc(II) and copper(II) species, respectively, thus following the expectations from simple ligand field arguments. Five-coordinate species do not form easily and were observed either in donor solvents or in the solid as 1D coordination polymers with distorted trigonal-bipyramidal coordination and different topologies.
我们用各种阴离子卤代和假卤代配体 X 制备了不同的 α,ω-二甲基三吡喃 TrpyMX 的中性过渡金属配合物,并就配位模式和结构畸变进行了研究。在整个系列中只观察到四配位和五配位物种。对于锌(II)和铜(II)来说,所有四配位物种都分别显示出未受约束但扭曲的四面体配位环境或受约束但扭曲的方平面配位环境,因此符合简单配体场论证的预期。五配位物种不易形成,在供体溶剂中或在固体中观察到的五配位物种都是一维配位聚合物,具有扭曲的三叉双锥配位和不同的拓扑结构。
Novel 2D Interpenetrated Structure and Occurrence of the Spin-crossover Phenomena of Assembled Complexes, Fe(NCX)<sub>2</sub>(bpp)<sub>2</sub>(X = S, Se, BH<sub>3</sub>; bpp = 1,3-Bis(4-pyridyl)propane)
Assembled complexes, Fe(NCX)2(bpp)2 (X = S, Se, BH3; bpp = 1,3-bis(4-pyridyl)propane), have been synthesized. Fe(NCS)2(bpp)2 had a novel 2D interpenetrated structure and showed a temperature-independent HS state, while Fe(NCSe)2(bpp)2 and Fe(NCBH3)2(bpp)2 exhibited a slight decrease in χMT and a complete spin-crossover phenomenon (T1⁄2=123 K), respectively.
Kinetics and equilibria of reversible chelate ring-opening nucleophilic substitution reactions of [(o-dimethylaminophenyl)dimethylarsine]-rhodium(III) complexes
作者:Arnaldo Peloso
DOI:10.1039/dt9810002429
日期:——
strongly influenced by the leaving group involved. A linear free-energy relationship of the type ΔG(m→t)‡=αΔG(m→t)⊖+β with a value of α of 0.75 exists for the activation and standard freeenergies of mer→trans reactions where a dissociative mechanism is considered to be operative. When Xn– is SCN–, N3–, or NO2–, the mer→trans reactions are acid-catalyzed, through protonation of the leaving group.
The thermal spin transitions of iron(II) spin-crossovercompounds [Fe(PM-iPA)2(NCS)2] (1) and [Fe(PM-iPA)2(NCSe)2] (2) (PM-iPA = N-(2′-pyridylmethyl)-isopropylamine) have occurred at T1/2 = 267 K and 376 K without thermalhysteresis. No light-induced excited spin state trapping (LIESST) effect was observed for compounds 1 and 2 even at 5 K. The iron(II) spin-crossovercompounds [Fe(PM-L)2(NCX)2] (PM-A
铁 (II) 自旋交叉化合物 [Fe(PM-iPA)2(NCS)2] (1) 和 [Fe(PM-iPA)2(NCSe)2] (2) (PM-iPA) 的热自旋跃迁= N-(2'-吡啶基甲基)-异丙胺) 在 T1/2 = 267 K 和 376 K 下发生,没有热滞后。即使在 5 K 下,化合物 1 和 2 也没有观察到光诱导的激发自旋态俘获 (LIESST) 效应。 铁 (II) 自旋交叉化合物 [Fe(PM-L)2(NCX)2] (PM-A = N-(2'-吡啶基甲基)-苯胺,PM-BiA = N-(2'-吡啶基甲基)-4-氨基联苯,PM-TeA = N-(2'-吡啶基甲基)-4-氨基三联苯,PM-PEA = N-(2'-吡啶基甲基)-4-(苯基乙炔基)苯胺和PM-AzA = N-(2'-吡啶基甲基)-4-(苯基偶氮)苯胺;X = S和Se)与具有π-系统的配体具有表现出 LIESST 效应,并且已经观察到临界