N,N′-Bis(trimethylsilyl)dicyandiamide

N,N-Bis(trimethylsilyl)dicyandiamide was prepared for the first time by the reaction of dicyandiamide with hexamethyldisilazane in boiling tetrahydrofuran. Thermal transformations of this compound were studied by DTA. The novel compound may be used in the synthesis of bis(trimethylsilyl)carbodiimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498–500, March, 1994.     

Kristallstruktur von N,N,N′,N′-Tetraisopropyl-p-phenylen-diammonium-dichlorid und-bis(tetrachloroaluminat)

Summary Protonation of the sterically overcrowded N,N,N,N-tetraisopropyl-p-phenylenediamine leads to a significant shortening of the C-N bond lengths of 7 pm as well as to a widening of the phenyl ipso-angle to 122°. All structural changes can be attributed to the twisted diisopropylammonium substituents and their electron acceptor properties.

     

N,N′-Bis(silylmethyl)azodicarboxamides

Russian Journal of General Chemistry - The first representatives of silicon-containing azocarboxamides, N,N′-bis(silylmethyl) azodicarboxamides, were synthesized by the reaction of...     

Five coordinate complexes of N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamide with copper Crystal and molecular structures of dichloro(N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamido)copper(II) and chloro(perchlorato)(N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamido)copper(II)

The title compound N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamide (DEAP) forms a 1:1 complex with anhydrous CuCl₂, [Cu(DEAP)Cl₂], (1) which was crystallized from EtOH solution in the monoclinic space group P2_{1/ n} with cell constant, a = 10.024(1); b = 13.122(1); c = 14.404(1) Å β = 101.31(1)° V = 1857.8(3) ų and Z = 4. The chloro-perchlorato complex, [Cu(DEAP)Cl(ClO₄)], (2) obtained in near quantitative yield by reacting (1) with an excess of NaClO₄ in EtOH, crystallized in the monoclinic space group P2_{1/ n} with cell constants, a = 7.965(1); b = 25.827(2); c = 10.046(1) Å β = 98.81(1)° V = 2042.2(4) ų and Z = 4. Both (1) and (2) contain 5-coordinated copper linked to DEAP through O～N～O donor set of atoms with covalently bonded chlorine atoms in (1) and chlorine and perchlorate groups in (2). The coordination geometry is intermediate between square pyramidal and trigonal bipyramidal, and is probably best described as a trigonally distorted rectangular pyramid.     

自旋捕捉技术在Ph3M(M=N,P, As,Sb, Bi)光解反应中的应用

本文用自旋捕捉技术、柱色谱与ESR波谱相结合的方法, 研究了Ph_3M(M=N, P, As, Sb, Bi)光解过程的活泼自由基。从自旋捕捉剂亚硝基特丁烷(t-BuNO)、苯亚甲基叔丁基氮氧化合物(PBN)或2,3,4,6-四甲基亚硝基苯(ND)与活泼自由基形成的自旋加合物的ESR波谱的超精细结构, 确证这些化合物光解过程中有Ph·自由基存在。从而可推断它们的光解初级过程包括Ph_3M的均裂, 即Ph_3M→Ph_2M·+Ph·。此外,因Ph—M键能的大小顺序为
Pb—P>Ph—As>Pb—Sb>Ph—Bi
所以Ph_2M·(M=As, Sb, Bi)的分解比Ph_2P·容易, 实验中只检查出Ph_2P·, 则正是所预期的。     

自旋捕捉技术在Ph_3M(M=N,P,As,Sb,Bi)光解反应中的应用

本文用自旋捕捉技术、柱色谱与ESR波谱相结合的方法,研究了Ph_3M(M=N、P,As,Sb,Bi)光解过程的活泼自由基。从自旋捕捉剂亚硝基特丁烷 (t-BuNO)、苯亚甲基叔丁基氮氧化合物(PBN)或2,3,4,6-四甲基亚硝基苯(ND)与活泼自由基形成的自旋加合物的ESR波谱的超精细结构,确证这些化合物光解过程中有Ph·自由基存在。从而可推断它们的光解初级过程包括Ph_3M的均裂,即Ph_3M→Ph_2M·+Ph·。此外,因Ph—M键能的大小顺序为 Pb—P>Ph—As>Pb—Sb>Ph—Bi所以Ph_2M·(M=As,Sb,Bi)的分解比Ph_2P·容易,实验中只检查出Ph_2P·,则正是所预期的。     

Synthesis and Characterization of Binuclear (μ-Oxalato) Copper(II) Complexes with N,N′-Diethylethylenediamine or N,N,N′-Trimethylethylenediamine

Three new binuclear w -oxalato copper(II) complexes of composition [(Cu(N,N' -dieten) H₂O)₂ox](ClO₄)₂ ·H₂O (1) (N,N'-dieten = N,N'-diethylethylenediamine, H₂ox = oxalic acid), [(Cu(trimeen)H₂O)₂ox](ClO₄)₂·2H₂O (2) (trimeen = N,N,N'-trimethylethylenediamine) and [(Cu(trimeen)H₂O)₂ox](NO₃)₂ ·2H₂O (3) have been isolated from the reactions of Cu(ClO₄)₂ ·6H₂O (or Cu(NO₃)₂ ·3H₂O), the appropriate amine and Na₂ox in water and have been characterized by IR and electronic spectroscopy and magnetic measurements. The crystal structure of [(Cu(N,N' -dieten)H₂O)₂ ox](ClO₄)₂.H₂O (1) has been determined by single-crystal X-ray analysis. The structure of ( 1 ) consists of binuclear cations [(N,N'-dieten)H₂O)Cu(ox)Cu(N,N'-dieten)H₂O)]²⁺, perchlorate anions and water molecules of crystallization. The copper atom is coordinated by two oxygen atoms of the oxalato ligand, two nitrogen atoms belonging to N,N'-dieten and one oxygen atom of water in a distorted square-pyramidal arrangement. The temperature dependence of magnetic susceptibilities (78-293 K) was measured for 1-3 . Magnetochemical measurements show that copper(II) ions in these compounds are antiferromagnetically coupled with J = -172 cm^-1, -172 cm^-1 and -168 cm^-1 (H = -2JS ₁ S ₂, S ₁= S ₂ = 1/2) for 1, 2 and 3, respectively.     

Spectroscopic investigation and thermal behavior of new carbonyl complexes [M(CO)4(N—N)(CuX)], (M = W,Mo; N—N = 2,2′-bipyridine, 1,10-phenanthroline; X = Cl,SCN)

[M(CO)₄(N—N)] reacts with CuCl to give new heterobimetallic metal carbonyls of the type [M(CO)₄(N—N)(CuCl)], M = W, Mo; N—N = 2,2-bipyridine (bipy), 1,10-phenanthroline (phen). Reactions of [M(CO)₄(N—N)(CuCl)] with NaSCN produced the series of complexes of general formula [M(CO)₄(N—N)(CuSCN)]. The i.r. spectral of all the bimetallic carbonyls exhibited the general four (CO) band patterns of the precursors. The u.v.–vis. spectral data for precursors and products showed bands associated with * (nitrogen ligands), dd (intrametal), as well as MLCT d* (nitrogen ligands) and MLCT d *(CO) transitions. The [M(CO)₄(N—N)(CuX)] (X = Cl, SCN) emission spectra showed only one band associated with the MLCT transition. The t.g. curves revealed a stepwise loss of CO groups. The initial decomposition temperatures of the [M(CO)₄(N—N)(CuX)] series suggest that the bimetallic compounds are indeed thermally less stable than their precursors, and the X-ray data showed the formation of MO₃, CuMO₄, Cu₂O and CuO as final decomposition products, M = W, Mo. The spectroscopic data suggests that the heterobimetallic compounds are polymeric.     

Ion-Exchange Processes M(II) → Fe(III) and Fe(III) → M(II) in Metal Hexacyanoferrate(II) Gelatin-Immobilized Matrices (M = Mn,Co, Ni,Cu, Zn,Cd)

Ion-exchange reactions M²⁺ Fe³⁺ and Fe³⁺ M²⁺ (M = Mn, Co, Ni, Cu, Zn, Cd) were studied in metal(II) hexacyanoferrate(II) gelatin-immobilized matrices M₂[Fe(CN)₆] in contact with aqueous FeCl₃ solutions and Fe₄[Fe(CN)₆]₃ in contact with aqueous MCl₂ solutions. It was shown that in both cases, M²⁺ was replaced by Fe³⁺ and Fe³⁺ was replaced by M²⁺ to some extent, but no complete replacement was observed in the M₂[Fe(CN)₆]–FeCl₃ or Fe₄[Fe(CN)₆]₃–MCl₂ systems under study. No electrophilic substitution Fe³⁺ Mn²⁺ was found to occur in any noticeable degree during the contact of Fe₄[Fe(CN)₆]₃ with aqueous MnCl₂ solutions even when this contact occurred for 1 h and longer.     

Tunability of the M(II)M(III)/M(II)(2) and M(III)(2)/M(II)M(III) (M=Mn, Co) couples in bis-μ-O,O'-carboxylato-μ-OR bridged complexes

A comparison of the electrochemical properties of a series of dinuclear complexes [M(2)(L)(RCO(2))(2)](+) with M = Mn or Co, L = 2,6-bis(N,N-bis-(2-pyridylmethyl)-sulfonamido)-4-methylphenolato (bpsmp(-)) or 2,6-bis(N,N-bis(2-pyridylmethyl)aminomethyl)-4-tert-butylphenolato (bpbp(-)) and R = H, CH(3), CF(3) or 3,4-dimethoxybenzoate demonstrates: (i) The electron-withdrawing sulfonyl groups in the backbone of bpsmp(-) stabilize the [M(2)(bpsmp)(RCO(2))(2)](+) complexes in their M(II)(2) oxidation state compared to their [M(2)(bpbp)(RCO(2))(2)](+) analogues. Manganese complexes are stabilised by approximately 550 mV and cobalt complexes by 650 mV. (ii) The auxiliary bridging carboxylato ligands further attenuate the metal-based redox chemistry. Substitution of two acetato for two trifluoroacetato ligands shifts redox couples by 300-400 mV. Within the working potential window, reversible or quasi-reversible M(II)M(III)? M(II)(2) processes range from 0.31 to 1.41 V for the [Co(2)(L)(RCO(2))(2)](+/2+) complexes and from 0.54 to 1.41 V for the [Mn(2)(L)(RCO(2))(2)](+/2+) complexes versus Ag/AgCl for E(M(II)M(III)/M(II)(2)). The extreme limits are defined by the complexes [M(2)(bpbp)(CH(3)CO(2))(2)](+) and [M(2)(bpsmp)(CF(3)CO(2))(2)](+) for both metal ions. Thus, tuning the ligand field in these dinuclear complexes makes possible a range of around 0.9 V and 1.49 V for the one-electron E(M(II)M(III)/M(II)(2)) couple of the Mn and Co complexes, respectively. The second one-electron process, M(II)M(III)? M(III)(2) was also observed in some cases. The lowest potential recorded for the E°(M(III)(2)/M(II)M(III)) couple was 0.63 V for [Co(2)(bpbp)(CH(3)CO(2))(2)](2+) and the highest measurable potential was 2.23 V versus Ag/AgCl for [Co(2)(bpsmp)(CF(3)CO(2))(2)](2+).     

Ring Closure of N,N′:N,N′-bis(decamethylene)-1, 4-diamino-2,5-bis(10-cyanodecyloxy)benzene (IV)

Recently, β-chloro-α,β-unsaturated carbonyl compounds have become increasingly useful as intermediates in organic synthesis. For example, reactions involving a number of different cyclic β-chloro-α,β-unsaturated ketones with a variety of reagents (a malonate anion², the anion of the dithiolane derivative of ethyl glyoxalate³, zinc-silver couple in methanol⁴, dimethylsulfoxonium methylide^5,6) have produced a series of structurally diverse and potentially fruitful synthetic intermediates. The second-mentioned reagent has also been successfully reacted with a β-chloro-α,β-unsaturated ester³.     

PVT properties of N,N,N′,N′-Tetraoctyl-3-oxapentanediamide (TODGA)

N,N,N??,N??-Tetraoctyl-3-oxapentanediamide (TODGA) is a versatile extractant for partitioning of fission products from highly active raffinate wastes. Its PVT properties are not available in literature. In this work, PVT properties of TODGA, estimated using group contribution method, are reported. A corresponding-states based equation as well as Wagner constants were also reported in the range of 273.15?K to critical temperature.     

Intermediates-induced CO2 Reduction Reaction Activity at Single-Atom M−N2 (M=Fe,Co, Ni) Sites

Single-atom M−N₂ (M=Fe, Co, Ni) catalysts exhibit high activity for CO₂ reduction reaction (CO₂RR). However, the CO₂RR mechanism and the origin of activity at the single-atom sites remain unclear, which hinders the development of single-atom M−N₂ catalysts. Here, using density functional theory calculations, we reveal intermediates-induced CO₂RR activity at the single-atom M−N₂ sites. At the M−N₂ sites, the asymmetric *O*CO configuration tends to split into *CO and *OH intermediates. Intermediates become part of the active moiety to form M−(CO)N₂ or M-(OH)N₂ sites, which optimizes the adsorption of intermediates on the M sites. The maximum free energy differences along the optimal CO₂RR pathway are 0.30, 0.54, and 0.28 eV for Fe−(OH)N₂, Co−(CO)N₂, and Ni−(OH)N₂ sites respectively, which is lower than those of Fe−N₂ (1.03 eV), Co−N₂ (1.24 eV) and Ni−N₂ (0.73 eV) sites. The intermediate modification can shift the d-band center of the spin-up (minority) state downward by regulating the charge distribution at the M sites, leading to less charge being accepted by the intermediates from the M sites. This work provides new insights into the understanding of the activity of single-atom M−N₂ sites.     

Manganese(II), nickel(II) and copper(II) complexes of (1,3-bis-aminomethyl) cyclohexane-N,N,N′,N′-tetrakisbenzimidazole

Summary Mn^II, Ni^II and Cu^II complexes of (1,3-bis-aminomethyl)-cyclohexane-N,N,N,N-tetrakisbenzimidazole (CDTB) have been prepared and characterized by spectral techniques. The complexes are monomeric and pseudo-octa-hedral, as evidenced by their e.p.r. spectra and analytical data. Parameters ², ², ² and for Cu^II complexes, and the crystal field splitting parameter (10 Dq) together with the Nephelauxetic ratio (), for Ni^II complexes, are reported.     

金属富氮化合物N3MN3(M=Be, Mg, Ca)的量子化学研究

使用密度泛函理论，在B3LYP／6—311＋G^＊水平上，对金属富氮化合物N3MN3（M=Be，Mg，Ca）的两种几何结构进行了理论计算，并对得到的几何结构做了振动频率分析．结果表明，所有几何结构的振动频率都是正的，没有虚频存在，说明这类金属富氮化合物是热力学稳定的，当嵌入金属离子后，M—N之间开始表现出显著的离子性特征，由线形N3某团组成的N3MN3比由三角形N3某团组成的N3MN3更稳定．     

Extraction of U(VI) and Th(IV) from nitric acid solutions with N,N,N′,N′-tetrahexylsuccinylamide

The results of monitoring of⁸⁵Kr volume activity in ground-level air of Prague over the period 1989–1995 are summariyed. Seasonal dependence with a maximum in late spring and summer months and a gradual increase of⁸⁵Kr concentration in the atmosphere were observed. Linear approximation of long-term trend in the period 1983–1995 gives the growth rate of 35 mBq·m^–3 per year. Exponential approximation provides an inter-year growth by 3.7% The measured values were compared to the prognosis of⁸⁵Kr contamination development of the atmosphere from the early 1980s. They were found to be near to the low estimate of the assumed development.     

Synthesis,characterization and nucleolytic property of bis(N,N′-dimethylglycinato)copper(II)

Aquabis(N,N-dimethylglycinato)copper(II) dihydrate, [Cu(dmg)₂(H₂O)]·2H₂O, has been synthesized and characterized by elemental analysis, FT-IR, magnetic data, thermal analysis, solution UV-visible spectroscopy, X-ray crystal structure analysis and electrospray ionization mass spectroscopy. The square pyramidal copper(II) complex crystallizes in the orthorhombic space group P2₁2₁2₁. The complex cleaves circular plasmid DNA (pBR322) in the presence of H₂O₂. The extent of cleavage varies with the concentration range of the complex, the type of buffer used, pH of buffer and the concentration of H₂O₂. Hydroxyl radical scavenger can inhibit the nucleolytic ability of this complex.     

N,N''''-bis(3-Chlorophenyl)urea

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ChemInform Abstract: Are Cyclogallenes (M2(GaH)3) (M: Li,Na, K) Aromatic?

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