Terminal Molybdenum Phosphides with d Electrons: Radical Character Promotes Coupling Chemistry

A terminal Mo phosphide was prepared through the group transfer of both P and Cl atoms from chloro‐substituted dibenzo‐7λ³‐phosphanorbornadiene. This compound represents the first structurally characterized terminal transition‐metal phosphide with valence d electrons. In the tetragonal ligand field, these electrons populate an orbital of d_xy parentage, an electronic configuration that accommodates both metal d electrons and a formal M≡P triple bond. Single‐electron oxidation affords a transient open‐shell terminal phosphide cation with significant spin density on P, as corroborated by continuous wave (CW) and pulse electron paramagnetic resonance (EPR) characterization. Facile P−P bond formation occurs from this species through intermolecular phosphide coupling.     

Phosphorus Oligomerization in Zintl Phases: Synthesis,Crystal Structure,and Bonding Analysis of Mixed Alkali and Alkaline‐Earth Metal Phosphides

Pnictides α‐Ba₅P₄ and KBa₄P₅ were prepared by melting the elements. The α‐Ba₅P₄ compound crystallizes in the orthorhombic system (Sm₅Ge₄‐type), space group Pnma, Z = 4, a = 8.330(3), b = 16.503(3), c = 8.405(2)Å, it contains two anionic species : P₂^4— dumbbells and P^3—. The KBa₄P₅ compound crystallizes in the tetragonal system, space group P4₃2₁2, Z = 4, a = 8.559(1), c = 16.102(2)Å, it contains trimers P₃^5— and dumbbells P₂^4—. The crystal structures were solved from single crystal X‐ray data and refined by full‐matrix least‐squares to agreement factors R1 = 0.047 and 0.038, respectively. Using ionic charges, α‐Ba₅P₄ is formulated as [5Ba²⁺, 2P^3—, P₂^4—] and KBa₄P₅ as [K⁺, 4Ba²⁺, P₂^4—, P₃^5—]. The level of oligomerisation in these structures depends upon the overall valence electron content, bonding within the anionic oligomers has been analyzed on the basis of EHMO calculations and compared to classical or hypervalent bonding in other phosphide compounds.     

Enantiomerically Pure Poly(oxymethylene) Helices: Correlating Helicity with Centrochirality

A first series of enantiomerically pure helical oligo(formaldehyde)s (=oligo(oxymethylen)s) 16 – 20 was synthesized. To induce the chiral uniformity of the helices, we used (1S)‐2,2‐dimethyl‐1‐phenylpropan‐1‐ol ( 14 ) to generate the end groups at the α and ω terminus (Scheme 6). Propanol 14 was accessible from its racemate by acetal formation with lactol 12 and separation of the diastereoisomers (Scheme 5). The helicity of the oligomers was investigated by temperature‐dependent CD, NMR, and optical‐rotation studies. In addition to qualitative considerations concerning the helicity of oligo(formaldehyde)s, we performed calculations of the dimer 17 and the pentamer 20 as well as X‐ray structure analyses of the dimer 17 and the tetramer 19 to establish the handedness of the helices and to correlate their sense with the absolute configuration of the inducing stereogenic center. The results may be of relevance with respect to induction and propagation of chirality in prebiotic chemistry.     

Group II B Metal Complexes with N-Benzoylglycine (Hippuric Acid) and their Amine Adducts

Zn(II), Cd(II) and Hg(II) complexes with N-benzoylglycine (Hippuric acid) (abbreviation HHippu) and their amine adducts are of the type M(Hippu)₂. H₂O, M(Hippu)₂, M(Hippu)₂. B (M = Zn, Cd and Hg, and B = piperazine, 1, 10-phenantroline; M = Zn and B = Pyridine; M = Hg and B = ethylenediamine), M(Hippu)₂? 2B (B = N-methylpiperazine, piperidine, morpholine and pyridine) and M(Hippu)₂?3B (M = Zn, Cd and B = ethylenediamine). The amine and amino-acid coordination are investigated with the infrared spectra. The monohydrate and anhydrous bis(hippurate)metal(II) have identical i.r. spectra, indicating that the water molecule is not coordinated to the metal ions. A monodentate coordination of the amino acid is found in the amine adducts of Zinc(II), while in those of Cadmium(II) and Mercury(II)a symmetrical or asymmetrical bidentate coordination through the (COO^?) group is suggested and a pseudooctahedral configuration proposed. Only in monohydrate, anhydrous and monopyridine bis(hippurate) Zinc(II) (with the lowering of the ν (NH) of the ? NH-group of the N-benzoylglycine) does this group appear to be involved in the metal coordination.     

边臂修饰的水杨醛亚胺第四族金属配合物的合成、结构及其乙烯聚合行为研究

通过给电子基团取代的(E)-2,4-二-叔丁基-6-(苯基亚胺基甲基)苯酚与等当量的M(CH₂Ph)₄ 反应制备了一系列第四族金属的双苄基配合物. 反应经历了甲苯消除及分子内苄基从金属至亚胺碳的迁移反应, 中间体的分离和结构鉴定证实了该反应历程. 通过核磁、元素分析和X-ray 单晶衍射表征了配合物的结构. 在甲基铝氧烷(MMAO)的活化下, 钛配合物可以高活性地催化乙烯的均聚合和乙烯/1-己烯的共聚合, 而相应的锆、铪的配合物在同样的条件下则几乎没有活性.     

Influence of the Structure of the Aminoalkyl Group in Polysiloxane on the Selectivity of Its Interaction with Metal Ions

Russian Journal of Applied Chemistry - Polysiloxanes containing nonchelating 3-aminopropyl and chelating N-(2-aminoethyl)-3-aminopropyl groups with the degree of functionalization of 28 and 24%,...     

Alkali Metal Bis(o-anisyl)phosphides: Characterization of MP(C(6)H(4)OMe-o)(2) (M = Li, Na) and Crystal Structure of a Sodium Secondary Organophosphide

Lithium bis(o-anisyl)phosphide (1)may be prepared by reaction of n-BuLi with bis(o-anisyl)phosphine in THF or toluene; sodium bis(o-anisyl)phosphide (2) is prepared by reaction of sodium with tris(o-anisyl)phosphine in liquid ammonia/THF; both compounds are isolated as unsolvated solids. 1 decomposes quantitatively in THF to give tetrakis(o-anisyl)diphosphine (4); 2 decomposes in THF to give a mixture containing 4 and bis(o-anisyl)phosphine. Addition of diglyme to 2 gives [Na{&mgr;-P(C(6)H(4)OMe-o)(2)}(MeO(CH(2)CH(2)O)(2)Me)](2) (2a), which has been characterized by single-crystal X-ray diffraction. Each Na atom in 2a is 6-coordinate, being bonded to two P atoms, three diglyme O atoms, and one O atom from an o-anisyl group. Crystal data: monoclinic, P2(1)/n, a = 14.549(4) ?, b = 18.555(6) ?, c = 15.846(4) ?, beta = 91.07(2) degrees, Z = 4, final R = 0.041, R(w) = 0.053.     

NaCu5(C2)3: The First Alkali Metal Transition Metal Acetylide with a Three‐dimensional Framework Structure

By heating the red residue of the reaction of NaC₂H and CuI in liquid ammonia at 463 K for 30 min in a dynamic vacuum orange polycrystalline NaCu₅(C₂)₃ is obtained. The crystal structure was solved and refined from X‐ray powder diffraction data (orthorhombic, Pnma, a = 732.80(2) pm, b = 1099.63(4) pm, c = 726.15(2) pm, Z = 4, R_B = 0.030). It consists of a three‐dimensional framework of Cu^I and C₂^2— ions with small channels running parallel to [100] and [001]. The sodium ions reside at the intersections of these channels. The vibrational spectra of NaCu₅(C₂)₃ show some similarities with the spectra of phenylethynylcopper(I), but they are different to those of Cu₂C₂. Therefore NaCu₅(C₂)₃ does probably not represent a crystalline model compound for the unknown structure of amorphous Cu₂C₂.     

Synthesis,spectroscopic characterization and electrochemical behaviour of nickel(II) complexes with C-meso-5,5,7,12,12,14-hexamethylcyclotetradecane (Me6[14]aneN4). Crystal structure of {Ni(Me6[14]aneN4)|I2

Summary A series of complexes of formula {Ni(Me₆[14]aneN₄)X₂| (Me₆[14]aneN₄) = C-meso-5,5,7,12,12,14-hexamethyl-1,4,-8,11-tetraazacyclotetradecane and X = N₃ (1), NCO (2), NCS (3), AcO (4) or I (5) has been synthesized. The crystal structure of (5) has been determined by X-ray diffraction methods. The nickel atom is surrounded by a square-planar array of nitrogen atoms, giving a low-spin complex. The macrocyclic ligand shows the most stable conformation, the six-membered rings exhibiting the chair form while the gauche conformation is adopted by the five-membered rings. Spectroscopic and magnetic data for (1)–(4) are consistent with octahedral coordination around the nickel atom, which is achieved by four N atoms of the macrocyclic ligand in a single plane and by two azido-N (1), cyanato-N (2), thiocyanato-N (3) and carboxylato-O (4) groups occupying the axial positions. An electrochemical study of the oxidation of (1)–(5) has been carried out in nonaqueous solvents and the prospects of synthesis of the corresponding nickel(III) species are discussed in the light of the electrochemical data.     

Metal Complexes with Alizarin Complexone AC: Electronic Absorption Spectra and Ligand Structure

The character of the electronic absorption spectra of metal complexes with alizarin complexone AC is determined by the ionization degree of the ligand and the ratio between its excited states with different contributions of tautomeric 9,10-, 1,10-, 2,9-, and 1,2-anthraquinoid resonance structures. It was found by the spectrophotometric, quantum-chemical, and correlation methods that the ligand in metal complexes can exist in three forms, namely, neutral and two ionized forms (containing one or two deprotonated hydroxy groups). For each of the latter two forms, four excited states with the dominating contribution of the 9,10-, 1,10-, 2,9-, or 1,2-anthraquinoid resonance structures are possible. The formation of red monometallic complexes involves the peri- or ortho-hydroxycarbonyl group in anthraquinoid tautomers (mostly, 1,2- and 2,9-structures). The color of bimetallic complexes is determined by four anthraquinoid structures of the ligand (from red 9,10- to blue 1,10-anthraquinones). Fluorine-containing complexes exist only as 1,2- and 1,10-anthraquinoid structures, which are responsible for their blue color. The known metal complexes with Alizarin Complexone AS were classified by their structures.     

Electrochromatography of Metal Ions on Zirconium(IV) Phosphoantimonate Papers: Quantitative Separation of Platinum(IV) from Platinum Group and Other Metal Ions

Abstract

Zirconium (IV) phosphoantimonate impregnated papers have been used to study the electrochromatographic behaviour of 29 metal ions in buffers of weak organic acids with their corresponding ammonium salts as background electrolytes at fixed voltage and time intervals. As a result of these investigations, the variation in the average mobility of metal ions with the ionisation constants of the organic acids used in buffers and other parameters such as atomic numbers and charge on the metal ions has been studied. On the basis of the differential mobilites of the metal ions, which depends on the ion exchange properties of Zr(IV) phosphoantimonate and the nature of the complexes formed with the electrolytes, some binary, ternary and quarternary separation have been achieved. Besides microgram separations (25 μg-100 μg) of Pt(TV) from Pt group and other metal ions have also been achieved.     

Salicylaldiminato Pyrrolylaldiminato Group 4 Metal Alkene Polymerization Catalysts: Combining High Activity with High Comonomer Incorporation

Summary: Treatment of Zr{3‐Bu^t‐2‐(O)C₆H₃CHN(C₆F₅)}Cl₃(THF) with K[2‐(C₆H₅NCH)C₄H₃N] yields Zr{3‐Bu^t‐2‐(O)C₆H₃CHN(C₆F₅)}{2‐(C₆H₅NCH)C₄H₃N}Cl₂, the first example of a (salicylaldiminato)(pyrrolylaldiminato)zirconium complex. The catalytic behavior of both the new zirconium pre‐catalyst and its titanium analogue have been determined. The titanium system is the more effective catalyst for both ethene homopolymerization and copolymerizations with hex‐1‐ene, norbornene, and cyclopentene. The titanium catalyst combines the high productivities of the bis(salicylaldiminato) parent complex with the more favorable comonomer incorporation of the bis(pyrrolylaldiminato) series.

Copolymerizations with pre‐catalysts 1 and 2 .     

一类含多氟烷基侧链的螺环化合物的合成及结构表征

A series of spiro compounds have been synthesized via several steps.The structure of these compounds wereconfirmed by ~1H NMR,~(13)C NMR,IR,MS spectra and X-ray diffraction analysis.The possible mechanism to formthese products was also proposed.