Bis-(bis-(1,3-diaminopropane)-copper(II) Tetracyanonickellate(II)) Tetrahydrate: Preparation, Characterization, and Crystal Structure of a Novel Molecular Tetracyanonickellate

Summary.  [Cu(tn)₂Ni(CN)₄]₂ċ4H₂O and Cu(tn)₂Ni(CN)₄ (tn = 1,3-diaminopropane) were prepared and characterized. The hydrate is unstable on air and readily dehydrates to Cu(tn)₂Ni(CN)₄. Crystal structure analysis of the hydrate at 150 K revealed a novel tetranuclear molecular structure of the tetracyanonickellate. The building elements are two [Cu(tn)₂]²⁺ cations (coordination numbers of Cu: 5 and 6, respectively), two [Ni(CN)₄)²⁻ anions, and crystal water. The two cations are linked by one tetracyanonickellate anion via bridging cyano groups placed in cis positions. The second anion is bound weakly (Cu-N = 2.82 ?) via one μ₂-bridging cyano ligand. The tetranuclear molecules and pairs of solvate water molecules are linked by strong hydrogen bonds, thus forming infinite planes which are linked in the third dimension by considerably weaker hydrogen bonds. Received May 9, 2000. Accepted (revised) August 21, 2000     

Synthesis and Determination of Alkali Metal Binding Selectivities of Chiral Macrocyclic Bisamides Derived from D-Mannitol and L-Threitol

Eight new chiral macrocyclic diamides derived from D-mannitol and L-threitol, possessing C₂ symmetry, are prepared. Their application for alkali metal binding processes is studied using the ESI-MS technique.     

Organoboron water,part I: Synthesis and multinuclear magnetic resonance studies on the structure of tetramethyldialuminoxane

The structure of tetramethyldialuminoxane was studied. The low‐temperature ¹H and ¹³C NMR spectra suggest that the methyl groups bridge the aluminum atoms in the dialuminoxane trimer. A new method of synthesis of methylaluminoxanes and tetramethyldialuminoxanes in the reaction of tetraethyldiboroxane (organoboron water) with trimethylaluminum (1:1 and 1:2 respectively) was applied to synthesize the investigated system. Copyright © 2004 John Wiley & Sons, Ltd.     

Local order and shape of a polymer chain in an external electric field

A solution of polymer chains in the presence of an external electric field is considered. Dipole-like interactions between polymer chain segment-vectors and the electric field are assumed to be proportional to the cosine of the angle between the segment-vector and the direction of the electric field. Parameters characterizing the shape of the chain (i.e., the chain end-to-end distance and cross-section per chain), and parameters describing the local order at the segmental and chain level (i.e., moments of the first and second Legendre polynomials 〈P₁〉 and 〈P₂〉 are calculated. The optical anisotropy and the molecular shape change induced by the external electric field are discussed.     

Method of characteristic for functional equations in polynomial form

Properties of continuous solutions of a second order polynomial-like iterated functional equation are given by considering its characteristic. A useful method to discuss the general case is described indeed in this procedure. Supported by NSF of China, Sichuan Provincial Youth Sci-Tech Foundation and Math. Grant of CAS     

Starlikeness of Hadamard product of certain analytic functions

An interesting criterion was given by Lashin (A.Y. Lashin, Some convolution properties of analytic functions, Appl. Math. Lett. 18 (2005) 135–138) to be starlike for convolution of analytic functions f, g such that Re[f^′(z)],Re[g^′(z)]β,,β<1 in the unit disc U. In this paper we shall improve this criterion.     

Mapping properties of weakly arcwise open dendroids

A dendroid X is said to be weakly arcwise open if for each point p of X each arc component of X?{p} either is open or has empty interior. We study various mapping properties of these dendroids. The leading problem is what classes of mappings between dendroids preserve the property of being weakly arcwise open.     

Non-alkaline bleaching of wood pulp using pulsed RF dielectric heating: comparison with pulsed microwave enhanced bleaching

Non-alkaline bleaching of thermo-mechanical pulps using 40 MHz RF dielectric capacitor heating is described. Experimental data obtained under RF irradiation are compared with non-alkaline bleaching under pulsed microwave at 2.45 GHz. Optimal processing time is determined. Effectiveness of non-alkaline bleaching of TMP in RF is shown to be close to that in microwave. Neither microwave nor RF irradiation, under non-alkaline bleaching conditions, is shown to result in detriment to the physical properties of the pulp.