Unusual phosphorus oligocycles from 1lamda3-phosphaalkynes and various halides of group 13 and 15 elements

Die Reaktionen von 1-lamda3-Phosphaalkinen mit den Halogeniden der Hauptgruppenelemente führen sehr häufig zu komplizierten Oligocyclen. Aufgrund vorausgehender, ausführlicher Untersuchungen von Mitgliedern unserer Arbeitsgruppe kann ein allgemeiner Reaktionsmechanismus formuliert werden. Die hier vorliegende Dissertation schließt an frühere Unversuchungen von Dautel, Löw und Ruf aus der Arbeitsgruppe Becker an und beschäftigt sich mit Reaktionen von 1-lamda3-Phosphaalkinen mit Dialkylchloralanen, Halogendiorganylphosphanen, Dichlor(dialkylamino)- sowie dem Dichlor[4-(dimethylamino)phenyl]arsan. Ziel war es, die Einflüsse von Alkyl- und Arylsubstituenten aus heteroleptischhen Organylelementhalogeniden der Gruppen 13 und 15 auf den Reaktionsweg, die spektroskopischen Eigenschaften und die Strukturen der Reaktionsprodukte zu klären. Die Umsetzungen von 1-lamda3-Phosphaalkinen mit Dichlor(diorganylamino)arsanen bei Zimmertemperatur führen zu völlig anderen Reaktionsprodukten. Allerdings sollte man hier zunächst anmerken, dass sich die As–N- und die P–N-Bindungsdissoziationsenergie mit 582(126) und 617(21) kJ•mol-1 unterscheiden. Als Folge kommt es im laufe der sehr unüberichtliden und von den Zwischenstufen her bislang nicht verstandenen Umsetzung zu einer Wanderung der Dialkylamino-Gruppe vom Arsen- zum Phosphoratom. Die aus Ansätzen von 2-tert-Butyl-1-lamda3-phosphaalkin und Dichlor(dialkylamino)arsanen im Molverhältnis 1:3 bei Zimmertemperatur in Cyclopentan isolierten 1-lamda5,3-lamda3,5-lamda3-Triphospha-dewarbenzol-Derivate fallen in hohen Ausbeuten an. Allerdings geht der Arsenanteil vermutlich als unlöslicher, polymerer Niederschlag von Arsen(I)chlorid vollständig verloren. Um den brauchbaren Bereich der Edukte zu erweitern, wurden Reaktionen der 1-lamda3-Phosphaalkine mit Dichlor[4-(dimethylamino)phenyl]arsan in Betrachtung gezogen. Diese Verbindung unterscheidet sich von einem Dichlor(diorganylamino)arsan lediglich durch Einschub einer Phenyl-Einheit in die As–N-Bindung, so dass nach dem sogenannten "Phenylogie-Prinzip" einer vergleichbaren Reaktivität ausgegangen werden kann. Zusammen mit Tris[4-(dimethylamino)phenyl]arsan konnte das Dichlor-Derivat in hoher Ausbeute direkt aus N,N-Dimethylanilin und Arsen(III)-chlorid entsprechend einer abgewandelten Vorschrift von Michaelis und Rabinerson erhalten werden. Quantenchemische Berechnungen wurden an mehreren Strukturen durchgeführt um optimierte Strukturdaten und relative Energien für unterschiedliche Isomere zu ermitteln.The reactions of 1-lamda3-phosphaalkynes with halides of main-group elements very often result in complicated cage compounds. Based on detailed investigations by several co-workers of our group, a general reaction scheme may now be outlined explaining even the formation of rather complicated cage structures. The research of my thesis is based on earlier studies of Dautel, Löw and Ruf of Becker’s group and deals with reactions between 1-lamda3-phospaalkynes and dialkylaluminium chlorides, halodiorganylphosphines or dichloro(dialkylamino)arsines in order to study the influence of alkyl and aryl groups in various mixed organyl halides of group 13 and group 15 elements on reaction routes and molecular structures. The reactions between 1lamda3-phosphaalkynes and dichloro(diorganylamino)arsines in a molar ratio of 3:1, performed in cyclopentane at ambient temperature, take quite a different route. To explain the underlying mechanism, one, however, has to realize first that the As–N and the P–N bonds differ in energy by values of about 582(126) and 617(21) kJ per mole. As a consequence, the insertion of the PC triple bond into one of the two As–Cl bonds is immediately followed by a transfer of the diorganylamino group from arsenic to phosphorus. Subsequently, the arsenic component of the starting material is completely lost, probably as a precipitate of insoluble “arsenic(I) chloride,” and an ylidic 1-lamda5,3-lamda3,5-lamda3-triphospha Dewar benzene is formed by further addition of 1lamda3-phosphaalkyne molecules. In order to widen the scope of different starting materials, reactions of 1-lamada3-phosphaalkynes with dichloro[4-(dimethylamino)phenyl]arsine were also taken into consideration. This compound differs from a dichloro(diorganylamino)arsine just by insertion of a phenyl unit into the As–N bond. In keeping with the so-called “phenylogous principle” it is expected to be of similar reactivity. Along with tris[4-(dimethylamino)phenyl]arsine the dichloro derivative could be obtained in high yield directly from N,N-dimethylaniline and arsenic(III) chloride according to the modified preparation of Michaelis and Rabinerson. Quantum chemical calculations were performed on the different structures in order to ascertain optimized structural data and relative energies for different isomers

Study of generalized Lemaître–Tolman–Bondi spacetime in Palatini

The objective of this paper is to investigate the continuation of Lemaître–Tolman–Bondi (LTB) space-time for dissipative dust configuration in the direction of Palatini f(R) theory. In this context, the generalized form of field and dynamical equations will be formulated. We explore the effects of kinematical variables and curvature invariant on our proposed fluid configuration. The significance of Palatini f(R) scalar variables computing through the orthogonal splitting of Riemann-tensor for dissipative dust spheres will be reported. Furthermore, two subcases of LTB space-time have been carried out to note down its symmetric aspects. It is revealed that extended LTB space-time has characteristics comparable to that of LTB and computed scalar variables in both situations have identical dependance on source profile even under the effects of Palatini technique

Synthesis and crystal structures of dialkyl[1,1-bis(alkylchloroalanyl)organylmethyl]phosphine_•dialkylchloroalane(1/1) complexes

<p>Dialkyl[1,1-bis(alkylchloroalanyl)organylmethyl]phosphine•dialkylchloroalane(1/1) complexes (<b>1a</b>–<b>1d</b>) were synthesized and fully characterized. In <b>1a</b>–<b>1d</b>, dative bonding between phosphorus or chlorine as a donor atom and aluminum as an acceptor atom results in a bicyclic system. The ³¹P{¹H} NMR spectra of all compounds dissolved in d₆-benzene indicate the presence of several isomers in solution. The ²⁷Al{¹H} NMR spectra of <b>1a</b>–<b>1d</b> dissolved in d₆-benzene as well show very broad singlets between 177 and 140 ppm. For all compounds, crystal structures consist of two fused four- and five-membered rings. The 1λ³-phosphaalkyne reacts at the Al–C bond of the starting material, whereas the Al–Cl moiety remains intact. The heterocycle isolated is a molecular complex of the underlying insertion compound and a third equivalent of dialkylaluminum chloride. The four- and five-membered rings both contain two chlorine-bridged aluminum atoms, Al3 and Al1, slightly more symmetrical than that between Al1 and Al6. In the four-membered ring the two aluminum atoms Al1 and Al6 approach each other at an average distance of 289.1 pm which tallies with the element–element distance (286.3 pm) in aluminum metal.</p

Synthesis and Assessment of Two Malonyl Dihydrazide Derivatives as Corrosion Inhibitors for Carbon Steel in Acidic Media: Experimental and Theoretical Studies

Despite the extensive use of carbon steel in all industrial sectors, particularly in the petroleum industry, its low corrosion resistance is an ongoing problem for these industries. In the current work, two malonyl dihydrazide derivatives, namely 2,2’-malonylbis (N-phenylhydrazine-1-carbothiamide (MBC) and N’1, N’3-bis(-2-hydroxybenzylidene) malonohydrazide (HBM), were examined as inhibitors for the carbon steel corrosion in 1.0 M HCl. Both MBC and HBM were characterised using thin-layer chromatography, elemental analysis, infrared spectroscopy, and nuclear magnetic resonance techniques. The corrosion tests were performed using mass loss measurements, polarisation curves, and electrochemical impedance spectroscopy. It is obtained from the mass loss studies that the optimal concentration for both inhibitors is 2.0 × 10−5 mol/L, and the inhibition efficiencies reached up to 90.7% and 84.5% for MBC and HBM, respectively. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP) indicate an increased impedance in the presence of both MBC and HBM and mixed-type inhibitors, respectively. Both inhibitors can mitigate corrosion in the range of 298–328 K. Values of free energy changes obtained from the Langmuir model suggest that the inhibitors suppress the corrosion process principally by chemisorption. The computational investigations were conducted to identify the factors connected with the anti-corrosive properties of the examined inhibitors

Thermal analysis of radiated (aluminum oxide)/water through a magnet based geometry subject to Cattaneo-Christov and Corcione’s Models

The study of heat transfer problems is of paramount significance due to their wider spectrum of applications specifically in heat engines, insulation, chemical and thermal engineering etc. The formulation of new model completed via enhanced nanofluid properties and under physical parameters and then in-depth mathematical investigation done via numerical approach and scrutinized the results for preeminent physical parameters. Thermal conductivity estimation under Corcione’s model increased by taking the particles concentration up to φ=0.6% and electrical conductivity diminishes from 0.999001 to 0.994036. Further, the eye bird analysis of the results revealed that the stretching number S1 from 0.1 to 1.3 and α2=0.1,0.2,0.3,0.4 resists the fluid flow over the surface and the nanofluid movement is slow compared to conventional liquid due to high viscous forces. Keeping the concentration φ% and Ha=0.1,0.2,0.3,0.4 the velocity G'(η) drops and it rises for increasing S1. Furthermore, the addition of radiative thermal flux (Rd) and internal heating effects (Hg) in the model increase its applicability for high thermal transport applications and is observed maximum for nanofluid. The local thermal rate at the surface could be enhanced by keeping Rd and Hg from 0.0 to 0.8 and minimal rate of heat transport is observed for simple fluid while it is dominant for nanofluid

Investigation of blood flow characteristics saturated by graphene/CuO hybrid nanoparticles under quadratic radiation using VIM: study for expanding/contracting channel

Abstract The importance of heat transfer in nanoliquids cannot avoided because it playing crucial role in the applied research fields. The potential area of applications included but restricted to applied thermal, biomedical, mechanical and chemical engineering. Therefore, it is the need of time to introduce new efficient way to enhance the heat transport rate in common fluids. The major aim of this research is to develop a new heat transport BHNF (Biohybrid Nanofluid Model) model in a channel having expanding/contracting walls up to Newtonian regimes of blood. The two sort of nanomaterials (Graphene + CuO) along with blood as base solvent are taken for the formation of working fluid. After that, the model analyzed via VIM (Variational Iteration Method) to examine the influence of involved physical parameters on the behavior of bionanofluids. The model results revealed that the bionanofluids velocity rises towards the lower and upper channel end when the expanding/contracting of the walls in the range of 0.1–1.6 (expanding case) and $$- \, 0.1$$ - 0.1 to $$1.6$$ 1.6 (contraction case). The working fluid attained high velocity in the neighboring of center portion of the channel. By increasing the walls permeability ( $${A}_{1}=\text{0.1,0.2,0.3,0.4}$$ A 1 = 0.1,0.2,0.3,0.4 ), the fluid movement can be reduced and optimum decrement observed about $$\eta =0.0$$ η = 0.0 . Further, inclusion of thermal radiation (Rd) and temperature coefficient ( $${\theta }_{r}$$ θ r ) observed good to enhance thermal mechanism in both hybrid and simple bionanofluids. The present ranges of Rd and $${\theta }_{r}$$ θ r considered from $$0.1$$ 0.1 to $$0.9$$ 0.9 and $$0.1$$ 0.1 to $$1.4$$ 1.4 , respectively. Thermal boundary layer reduced in the case of simple bionanoliquid keeping $${P}_{r}=21.0$$ P r = 21.0

Investigation of improved heat transport featuring in dissipative ternary nanofluid over a stretched wavy cylinder under thermal slip

Purpose: and Methodology: The heat transport investigation in non-Newtonian fluids suspended by distinct sort of nanoparticles is a rich motive in the present time. Therefore, inspired by the physical characteristics of base fluid and ternary nanoparticles (Al2O3-CuO-Cu), a comprehensive analysis conducted over a cylinder with wavy radius with special emphasis in Saddle and Nodal points. The key effects of dissipation, the first order thermal slip, surface convection and stretching/shrinking added in the model. The acquired model is then examined via RK-scheme and portrayed the results against the physical ranges of the parameters. Key findings: A comprehensive discussion of the results provided that the nanofluid velocity increased for higher Casson number (α=0.5,1.0,1.5,2.0) and is examined optimum for stretched cylinder surface. The higher viscous dissipation which results the effects of Eckert number (Ec=0.01,0.02,0.03,0.04), surface convection due to Biot number (B1=0.1,0.2,0.3,0.4) and the first order thermal slip (α1=0.1,0.3,0.5,0.7) are the key physical factors to acquire the favorable heat transfer amount for the practical interest. Further, the particles concentration in the range of 1%–6% is observed good to increase the heat transmission in ternary nanoliquid and the values of effective characteristics (dynamics viscosity and thermal conductivity) upsurges against the concentration factor up to 6%

Gum Arabic-Magnetite Nanocomposite as an Eco-Friendly Adsorbent for Removal of Lead(II) Ions from Aqueous Solutions: Equilibrium, Kinetic and Thermodynamic Studies

In this study, a gum Arabic-magnetite nanocomposite (GA/MNPs) was synthesized using the solution method. The prepared nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). The prepared composite was evaluated for the adsorption of lead(II) ions from aqueous solutions. The controlling factors such as pH, contact time, adsorbent dose, initial ion concentration, and temperature were investigated. The optimum adsorption conditions were found to be 0.3 g/50 mL, pH = 6.00, and contact time of 30 min. The experimental data well fitted the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity was determined as 50.5 mg/g. Thermodynamic parameters were calculated postulating an endothermic and spontaneous process and a physio-sorption pathway

Green synthesis of Ag/Fe3O4 nanoparticles using Mentha longifolia flower extract: evaluation of its antioxidant and anti-lung cancer effects

Herein, a bio-inspired synthetic method for Ag NP adorned biofunctionalized magnetic nanocomposite has been demonstrated. In the procedure, Mentha longifolia flower extract was employed as a template for the green reduction of immobilized Ag ions to corresponding NPs and subsequent stabilization. The phytochemical modification also facilitated the Fe3O4 NPs to protect from self-aggregation. The as-synthesized Ag/Fe3O4 nanocomposite material was characterized by SEM, TEM, EDX, elemental mapping, VSM, XRD and ICP-OES methods. Towards the biological application, the material was first explored in the anti-oxidant study following DPPH assay and it exhibited a significant radical scavenging capacity. The application of Ag/Fe3O4 nanocomposite was further progressed in the anticancer study against standard human lung cancer cell lines (A549 and H358). Cytotoxicity of the material against the cell lines were determined in terms of % cell viability following MTT method and was found to decrease with increase in the material load