Supramolecular Cobalt(II), Copper(II) and Cadmium(II) Complexes Obtained from a Proton Transfer Compound including Pyridine-2,6-dicarboxylate and Propane-1,3-diaminium Ions; Synthesis,Characterization and Crystal Structure

Abstract The three complexes (pnH₂)[Co(pydc)₂]·4H₂O 1, (pnH₂)[Cu(pydc)₂]·4H₂O 2, and (pnH₂)[Cd(pydc)₂]·3.5H₂O 3 (pn: propane-1,3-diamine, pydc: pyridine-2,6-dicarboxylate) were prepared using a proton transfer compound (pnH₂)(pydc)·(pydcH₂)·2.5H₂O, LH ₂ and corresponding metallic salts. The characterization was carried out using elemental analysis, IR and NMR spectroscopy, and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in space group P , but complex 3 crystallizes in space group P2/c. Cell parameters of the complexes are a = 8.449(1) ?, b = 11.668(1) ?, c = 12.801(1) ?, α = 115.748(2)°, β = 93.038(2)°, γ = 97.867(2)° for 1; a = 7.973(2) ?, b = 16.632(2) ?, c = 25.280(5) ?, α = 94.178(6)°, β = 95.186(6)°, γ = 91.603(5)° for 2 and a = 20.055(1) ?, b = 13.8161(9) ?, c = 8.2418(5) ?, β = 100.086(1)° for 3. The three crystal structures illustrate that the metal ion is six-coordinated by two pydc’s. In structures of 2 and 3, it can be seen that propane-1,3-diaminium fragments have different conformations. The complexes have ion-pairing interactions, O–H···O, N–H···O and C–H···O hydrogen bonds, π–π stacking as well as van der Waals forces as the main factors in formation of their supramolecular structures. Index Abstract Supramolecular Cobalt(II), Copper(II) and Cadmium(II) Complexes Obtained from a Proton Transfer Compound including Pyridine-2,6-dicarboxylate and Propane-1,3-diaminium Ions; Synthesis, Characterization and Crystal Structure Hossein Aghabozorg, Mohammad Ghadermazi,Bahar Nakhjavan, Faranak Manteghi The synthesis, characterization, crystal structure and non-covalent interactions of three supramolecular complexes of Co(II), Cu(II) and Cd(II) obtained by the reaction of a proton transfer compound i.e. (pnH₂)(pydc)·(pydcH₂)·2.5H₂O with the corresponding metallic salts are reported. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Semi‐implicit schemes for transient Navier–Stokes equations and eddy viscosity models

This study presents two computational schemes for the numerical approximation of solutions to eddy viscosity models as well as transient Navier–Stokes equations. The eddy viscosity model is one example of a class of Large Eddy Simulation models, which are used to simulate turbulent flow. The first approximation scheme is a first order single step method that treats the nonlinear term using a semi‐implicit discretization. The second scheme employs a two step approach that applies a Crank–Nicolson method for the nonlinear term while also retaining the semi‐implicit treatment used in the first scheme. A finite element approximation is used in the spatial discretization of the partial differential equations. The convergence analysis for both schemes is discussed in detail, and numerical results are given for two test problems one of which is the two dimensional flow around a cylinder. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009