The coordination chemistry of perfluorovinyl substituted phosphine ligands, a crystallographic and spectroscopic study. Co-crystallisation of both cis- and trans-isomers of [PtCl2{P(i)pr2(CF=CF2)}2] within the same unit cell

The coordination chemistry of the perfluorovinyl phosphines PEt2(CF=CF2), P(i)Pr2(CF=CF2), PCy,(CF=CF2) and PPh(CF=CF2)2 to rhodium(I), palladium(II), and platinum(II) centres has been investigated. The electronic properties of the ligands are estimated based on v(CO) and 1J(Rh-P) values. X-Ray diffraction data for the square-planar Pd(II) and Pt(II) perfluorovinyl-phosphine containing complexes allow estimates of the steric demand for the series of ligands PPh2(CF=CF2), PEt2(CF=CF2), P(i)Pr2(CF=CF2), PCy2(CF=CF2) and PPh(CF=CF2)2 to be determined. The (CF=CF2) fragment is found to be more electron withdrawing than (C6F5) yet sterically less demanding. These ligands therefore provide a range of electron-neutral to phosphite-like electronic properties combined with a range of steric demands. This study also reveals that short intramolecular interactions from the metal centre to the beta-fluorine atom cis to phosphorus of the CF=CF2 groups are observed in all-trans square planar complexes of the ligands. Unusually, the complex [PtCl2{P(i)Pr2(CF=CF2)}2] crystallises with both cis- and trans-isomers present in the unit cell. It appears that co-crystallisation of both isomers occurs in order to maximise fluorous regions in the crystal packing, and the extended structure displays short fluorine-fluorine contacts. The generation of mixed geometries seems to be a phenomenon of crystallisation, as solution phase NMR studies reveal the presence of only the trans-isomer.     

FT-Raman, FT-IR and NMR spectra, vibrational assignments and density functional studies of 1,3-bis(benzimidazol-2-yl)-2-thiapropane ligand and its Zn(II) halide complexes

1,3-bis(benzimidazol-2-yl)-2-thiapropane (L) ligand and its zinc halide ZnX₂ (X = Cl, Br, I) complexes have been synthesized. The compounds were characterized using the elemental analysis, molar conductivity, FT-Raman, FT-IR (mid i.r., far i.r.), ¹H and ¹³C NMR spectra, and quantum chemical calculations performed with Gaussian 03 package program set. The optimized geometries and vibrational frequencies of the ligand and [Zn(L)Cl₂] complex were calculated using the DFT/B3LYP method with a 6–31g(d) basis set. The geometry optimization of [Zn(L)Cl₂] yields a slightly distorted tetrahedral environment around Zn ion, while the molecule clearly reveals the Cs symmetry. The molar conductivity data reveals that the complexes are neutral. The ligand is bidentate, via two of the imine nitrogen atoms in the bis-imidazole ring units, and together with the monodentate coordination of the two halides to the metal centre.     

Operational Methods and Truncated Exponential-Based Mittag-Leffler Polynomials

This article deals with the introduction of truncated exponential-based Mittag-Leffler polynomials and derivation of their properties. The operational correspondence between these polynomials and Mittag-Leffler polynomials is established. An integral representation for these polynomials is also derived.     

Generalized and mixed type Gegenbauer polynomials

In this paper, a new generalized form of the Gegenbauer polynomials is introduced by using the integral representation method. Further, the Hermite–Gegenbauer and the Laguerre–Gegenbauer polynomials are introduced by using the operational identities associated with the generalized Hermite and Laguerre polynomials of two variables.     

On flow of a fourth‐grade fluid with heat transfer

The influence of heat transfer on the steady flow of a fourth‐grade fluid between two stationary parallel porous plates is studied. The flow is engendered under the application of a constant pressure gradient. The concept of homotopy analysis method is utilized for the series solution of the governing problem. Numerical solution has been also carried out. In addition, both analytic and numerical solutions are compared. The variations of embedded parameters into the solution are predicted through the graphical representations. Copyright © 2010 John Wiley & Sons, Ltd.     

Generalized Bessel Functions and Lie Algebra Representation

The generalized Bessel functions (GBF) are framed within the context of the representation Q(ω,m ₀) of the three-dimensional Lie algebra . The analysis has been carried out by generalizing the formalism relevant to Bessel functions. New generating relations and identities involving various forms of GBF are obtained. Certain known results are also mentioned as special cases.Mathematics Subject Classifications (2000) 33C10, 33C80, 33E20.     

Marine Algae-PLA composites as de novo alternative to porcine derived collagen membranes

Resorbable and volume-stable collagen matrices have been preferred as grafting materials for diverse clinical applications in recent years. On the other hand, there is always an existing risk of transmission of infection with the cells or the tissues of the graft in using such collagen matrices. Moreover, considering the economic aspects, there is also a need for cost-efficient alternative materials. In this sense, marine algae can be considered as alternatives since they represent vast and cheap source of potential biopolymers. This work covers a comprehensive cytocompatibility study of composite biopolymers derived from different types of marine algae.     

Double-stratified Marangoni boundary layer flow of Casson nanoliquid: probable error application

Journal of Thermal Analysis and Calorimetry - The present research is manifested to observe the impact of double stratification in the Marangoni convective flow of the Casson nanoliquid model...