Band 44, Heft 1

Zinc borate having the formula of 4ZnO·B 2 O 3 ·H 2 O has been used as a fire retardant for polymers requiring high processing temperatures since it has a high dehydration temperature (around 415°C). The effects of reaction time, reaction temperature were investigated on the heterogeneous reaction between solid zinc oxide and boric acid solution. A stoichiometric amount of zinc oxide and 5.0% excess boric acid were used in experiments and the other parameters, mixing speed (1700 rpm), the solid-liquid ratio of 20%, and the amount of seed crystal (3.9% wt) were kept constant for all experiments. A 91.1% conversion was obtained at 120°C for 5 h of reaction time. Precipitated product was filtered and washed by hot water to remove the excess boric acid. Finally it was dried until reaching to a constant mass in an air circulating oven at 105°C. Powder products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectrum and XRD pattern of powders are consistent with data of the zinc borate given in the literature. According to SEM analysis, whiskers are less than 1 μm in diameter and their lengths are in the range of 1–10 μm.

Dithiocarbamate complexes [Cd(S 2 CNCy 2 ) 2 (py)] (1) , [In(S 2 CNCy 2 ) 3 ]·2py (2) and [Zn(S2CNCy 2 ) 2 (py)] (3) were synthesized and toluene solution of (1) and (2) was used as dual source precursor for the synthesis of CdIn 2 S 4 (CIS), while that of (1) and (3) was applied for the deposition of Cd 7.23 Zn 2.77 S 10 –ZnS composite (CZS-ZS) thin film photoan-odes by employing single step aerosol assisted chemical vapor deposition (AACVD) technique. Deposition experiments were performed at 500°C under an inert ambient of argon gas. The structural properties of deposited films were evaluated by using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The field emission scanning electron microscopy (FESEM) exposed surface morphologies while UV-Visible spectrophotometry revealed that CIS is low band gap photoanode in comparison to CZS-ZS. The comparison of photoelectrochemical (PEC) responses measured in identical conditions in terms of linear sweep voltammetry (LSV) depicts photocurrent density of 4.4 mA /cm 2 and 2.9 mA/cm 2 at applied potential of 0.7 V under solar light intensity of 100 mW/cm 2 for CIS and CZS-ZS respectively. Further, electrochemical impedance spectroscopy (EIS) confirms that PEC properties of CIS are superior to CZS-ZS photoanode as the former offer less charge transfer resistance (R ct ) 0.03 MΩ in comparison to CZS-ZS having R ct value of 0.06 MΩ.

New cyclic and spirocyclic aminosilanes were synthesised using ethylenediamine, 2-aminobenzylamine, 1,8-diaminonaphthalene, o-phenylenediamine, and trans -cyclohexane-1,2-diamine as starting material. These diamines were converted into aminosilanes using silicon tetrachloride and dimethyldichlorosilane directly and via the N,N’ -bis(trimethylsilylated) amino derivatives. 15 new compounds of the type (diamino)(SiMe 3 ) 2 , (diamino) 2 Si, (diamino)SiMe 2 , and (diamino)SiCl 2 have been prepared. The formation of two cyclotrisilazane derivatives was observed starting from ( N,N’ -2-aminobenzylamino)dichlorosilane by trimerisation. All synthesised compounds have been characterised with NMR-, Raman-, or IR-spectroscopy, mass-spectrometry, and boiling or melting point. Single-crystal X-ray structure analyses of several derivatives have been performed. The degree of substitution with trimethylsilyl groups in the final compounds depends on the ring size of the spirocycles. It was shown with quantum chemical calculations on the M062X/6-31G(d) level that trimethylsilyl groups have a stabilising effect on 5-membered ring systems and a destabilising effect on 6-membered rings in these compounds.

In this study, essential (Ca, Cr, Cu, Fe, K, Mg, Na, P, Zn), and non-essential (Al, Ni, Pb) element contents of the drinking and baby water samples which are sold in the local market and tap water samples in Istanbul were examined. It was determined that elements of Cr, Cu, Fe, P, Zn, Al, and Ni were below detection limits in all water samples. Among the non-essential elements analyzed in water samples, Pb was the only detected element. At the same time, the percentages that meet the daily element requirements of infants were also calculated. As a result of the evaluations made, there is no significant difference in infant nutrition between baby waters and other drinking waters in terms of the element content.

The syntheses of three different amidinosilanes of the type Me 2 Si[N=C(Ph)R] 2 with R = pyrrolidino, morpholino, and diethylamino and one derivative with the composition R 2 Si[N=C(Ph)R] 2 with R = morpholino are reported. These compounds were prepared in one-pot syntheses including three consecutive steps. All products are analysed by single crystal X-ray diffraction, NMR, and Raman spectroscopy. The Si–N=C–N units of these compounds show characteristic structural features and cause a significant high field shift of the 29 Si NMR signals.

We present the synthesis and characterization of halide-terminated colloidal Ge nanoparticles of 2–10 nm with a narrow size distribution, synthesized via a novel reaction route. The nanoparticles are prepared by the disproportionation reaction of metastable Ge(I)X solutions and are obtained in a maximum yield of 79%. Control of the nanoparticle size is achieved by varying the aging time and/or temperature. The halide termination of the nanoparticles is a perfect prerequisite for further surface functionalization but also leads to a high sensitivity of the germanium nanoparticles to water and air.

This paper presents antimalarial activity of several triphenyltin(IV) aminobenzoate compounds synthesized from the reaction of triphenyltin(IV) hydroxide with 2-, 3-, and 4-aminobenzoic acid. The activity of the compounds as anti-malaria agents was evaluated using Plasmodium falciparum , and demonstrated that the compounds have about the same IC 50 with that of chloroquine (2×10 −3 μg/mL) applied as the positive control. The result also showed that the Plasmodium is non-resistent to the compounds synthesized, which is the opposite to chloroquine.

The reaction between CdCl 2 and PPh 2 {C 6 H 4 [CH 2 N(CH 2 CH 2 ) 2 O]-2} ( 1 ) in a 1:1 molar ratio resulted in the cadmium(II) complex CdCl 2 [PPh 2 {C 6 H 4 [CH 2 N(CH 2 CH 2 ) 2 O]-2}] ( 2 ). The complex 2 was characterized in solution by NMR spectroscopy ( 1 H, 13 C, and 31 P). Single-crystal X-ray diffraction studies revealed no intramolecular N→P interaction in 1 . The phosphane ligand behaves as a P,N chelating moiety in the cadmium complex 2 , thus resulting in a species containing distorted tetrahedral environments around cadmium and phosphorus. Short intermolecular interactions CH‧‧‧π aryl and CH‧‧‧O in 1 and CH‧‧‧π aryl and CH‧‧‧Cl in 2 resulted in supramolecular networks.

The condensation of 4,4’-dimethyldiphenylether with tellurium tetrachloride yielded 2,8-dimethyl-10,10-dichlorophenoxatellurine ( 3 ), which was characterized by X-ray diffraction. Unlike the parent phenoxatellurine ( 1 ) and the 10,10,-dichlorophenoxatellurine ( 2 ) showing butterfly conformations, 3 reveals a planar ring structure.

The complex [Pb(phen)(4-NB)(CH 3 COO)] of lead(II) was prepared and characterized by means of elemental analysis, FT-IR, and single crystal X-ray analysis, where phen = 1,10-phenanthroline, 4-NB = 4-nitrobenzoate. The single crystal X-ray analysis indicates that the complex is a monomeric species, including two carboxylate ligands, and adopts a hemidirected structure. It is further extended by intermolecular C−H⋯O hydrogen bonds, π–π interactions and secondary Pb⋯O interactions to form two-dimensional supramolecular architecture.

Crystallization of [(Ph 3 Sn) 2 SeO 4 ] ⋅ 1.5H 2 O in methanol leads to the formation of [{(Ph 3 Sn) 2 SeO 4 } ⋅ CH 3 OH] n ( 1 ) which constitutes a new specimen of organotin(IV) selenate derivatives. In the solid state, complex 1 is arranged in polymeric zig-zag chains, composed of alternating Ph 3 Sn and SeO 4 groups. In addition, pendant Ph 3 Sn ⋅ CH 3 OH moieties are branched along chains according to a syndiotactic organization and via Sn-O-Se connections. From a supramolecular point of view, intermolecular hydrogen bonds established between the selenate groups (uncoordinated oxygen) and the hydroxyl functions (CH 3 OH) of the pendant groups link the chains together.

A new metal-organic coordination polymer, [Pb(L)(adip) 0.5 ] ( 1 ) was synthesized under hydrothermal conditions by using 1-(1 H -imidazo[4,5-f][1,10]phenanthrolin-2-yl)naphthalen-2-ol (HL) and adipic acid (H 2 adip). The complex 1 was characterized by diffraction and elemental analyses. In complex 1 , the binuclear [Pb 2 L 2 ] units were formed by the OH-deprotonation bridging neighboring Pb(II) atoms, and the adipate linked the binuclear [Pb 2 L 2 ] units to form a symmetric one-dimensional chain. The 1D chain was further extended to the 2D supramolecular layer structure through π-π interactions between the L ligands.

The previously reported Mn 0 –Mg II bonded heterobimetallic compound [L † Mn–Mg( Mes Nacnac)] (L † = −N(Ar † )(SiPr i 3 ), Ar † = C 6 H 2 {C(H)Ph 2 } 2 Pr i -2,6,4; Mes Nacnac = [(MesNCMe) 2 CH] − ; Mes = mesityl) forms an adduct complex, [L † Mn–Mg(THF)( Mes Nacnac)], when dissolved in THF. Adventitious water is shown to be reduced by [L † Mn–Mg( Mes Nacnac)] to give the hydroxide bridged heterobimetallic, [L † Mn( μ -OH) 2 Mg( Mes Nacnac)]. The Mn 0 –Mg II bonded heterobimtallic reductively disproportionates CO 2 , affording the carbonate bridged species, [{L † Mn( μ -CO 3 )Mg(THF) ( Mes Nacnac)} 2 ], in the presence of THF. The three new compounds have been crystallographically characterized.

This review covers over fifty Pt (II) complexes of the compositions PtP 3 X (X = H, OL, NL, BL, Cl, SL, Br, or I). These complexes crystallized in three crystal classes: monoclinic (23 examples) triclinic (17 examples) and orthorhombic (11 examples). The PtP 3 Cl is most common with 23 examples. There are variable combinations of organophosphines monodentate – P; bidentate- P,P; P,N; P,B; and tridentate – P,P,P; P,O,P; P,N,P; and P,S,P. The structural parameters (Pt–L, L–Pt–L) are analyzed and discussed with an attention to the distortion of a square-planar geometry about the Pt (II) atoms as well as of trans-influence. The sums of Pt–L (x4) bond distances growing with covalent radius of the X-atoms.

We report herein structural characterization of monomeric platinum complexes of the composition: Pt(η 4 –P 4 L), Pt(η 4 –P 3 SiL), Pt(η 4 –P 2 N 2 L), Pt(η 4 –P 2 S 2 L), Pt(η 4 –P 2 C 2 L), Pt(η 4 –PN 3 L), and Pt(η 4 –PN 2 OL). The tetradentate ligands with 10-, 11-, 12-, 14-, and 16-membered macrocycles create a variety of chelate bond angles. A distorted square-planar geometry about Pt(II) atoms with cis–configuration by far prevail. There is an example Pt(η 4 –P 3 SiL) in which the respective donor atoms build up a trigonal-pyramidal geometry about Pt(II) atom.

The topic of computing the topological indices (TIs) being a graph-theoretic modeling of the networks or discrete structures has become an important area of research nowadays because of its immense applications in various branches of the applied sciences. TIs have played a vital role in mathematical chemistry since the pioneering work of famous chemist Harry Wiener in 1947. However, in recent years, their capability and popularity has increased significantly because of the findings of the different physical and chemical investigations in the various chemical networks and the structures arising from the drug designs. In additions, TIs are also frequently used to study the quantitative structure property relationships (QSPRs) and quantitative structure activity relationships (QSARs) models which correlate the chemical structures with their physio-chemical properties and biological activities in a dataset of chemicals. These models are very important and useful for the research community working in the wider area of cheminformatics which is an interdisciplinary field combining mathematics, chemistry, and information science. The aim of this editorial is to arrange new methods, techniques, models, and algorithms to study the various theoretical and computational aspects of the different types of these topological indices for the various molecular structures.

In recent past, porphyrin-based dendrimers have gained great attraction due to their usefulness in nano devices and photo-dynamic therapy. New technologies based upon nano-materials or dendrimers have potential to overcome the problems due to conventional drug delivery, like toxicity, poor solubility and poor release pattern of drugs. The chemical and physical properties of these highly branched nanometer sized dendrimers depend on their structure. In chemical network theory, various topological indices are used to predict chemical properties of molecules(dendrimers). Among many useful topological descriptors forgotten coindex is relatively less explored but is found very useful in material engineering, pharmaceutical and chemical industries. In this article, we consider some special dendrimers, like poly(propyl) ether imine, porphyrin, and zinc-porphyrin, and nanostars like D 1 [ k ] and D 2 [ k ] and compute forgotten coindex for these important structures.

Chemical graph theory has become a prime gadget for mathematical chemistry due to its wide range of graph theoretical applications for solving molecular problems. A numerical quantity is named as topological index which explains the topological characteristics of a chemical graph. Recently face centered cubic lattice FCC ( n ) attracted large attention due to its prominent and distinguished properties. Mujahed and Nagy (2016, 2018) calculated the precise expression for Wiener index and hyper-Wiener index on rows of unit cells of FCC ( n ). In this paper, we present the ECI (eccentric-connectivity index), TCI (total-eccentricity index), CEI (connective eccentric index), and first eccentric Zagreb index of face centered cubic lattice.

It is interesting to study the molecular topology that provides a base for relationship of physicochemical property of a definite molecule. The topology of a molecule and the irregularity of the structure plays a vital character in shaping properties of the structure like enthalpy and entropy. In this article, we are interested to calculate some irregular topological indices of two classes of metal organic frameworks (MOFs) namely BHT (Butylated hydroxytoluene) based metal (M = Co, Fe, Mn, Cr) organic frameworks (MBHT) and M1TPyP-M2 (TPyP = 5, 10, 15, 20-tetrakis (4-pyridyl) porphyrin and M1, M2, = Fe and Co) MOFs. Also we compare our results graphically.

Topological descriptors are the graph invariants that are used to explore the molecular topology of the molecular/chemical graphs. In QSAR/QSPR research, physico-chemical characteristics and topological invariants including Randić, atom-bond connectivity, and geometric arithmetic invariants are utilized to corelate and estimate the structure relationship and bioactivity of certain chemical compounds. Graph theory and discrete mathematics have discovered an impressive utilization in the area of research. In this article, we investigate the valency-depended invariants for certain chemical networks like generalized Aztec diamonds and tetrahedral diamond lattice. Moreover, the exact values of invariants for these categories of chemical networks are derived.

In this article, we compute the vertex Padmakar-Ivan ( PI v ) index, vertex Szeged ( Sz v ) index, edge Padmakar-Ivan ( PI e ) index, edge Szeged ( Sz e ) index, weighted vertex Padmakar-Ivan ( wPI v ) index, and weighted vertex Szeged ( wSz v ) index of a graph product called subdivision vertex-edge join of graphs.

Metal-organic frameworks (MOF(n)) are organic-inorganic hybrid crystalline porous materials that consist of a regular array of positively charged metal ions surrounded by organic ‘linker’ molecules. The metal ions form nodes that bind the arms of the linkers together to form a repeating, cage-like structure. Moreover, in a chemical structure or molecular graph, edges and vertices are known as bonds and atoms, respectively. Metric dimension being a subsets of atoms with minimum cardinality is used in the substrcturing of the chemical compounds in the molecular structures. Fractional metric dimension is weighted version of metric dimension that associate a numeric value to the identified subset of atoms. In this paper, we have computed the fractional metric dimension of metal organic framework (MOF(n)) for n ≡ 0( mod )2.

A topological descriptor is a mathematical illustration of a molecular construction that relates particular physicochemical properties of primary molecular structure as well its mathematical depiction. Topological co-indices are usually applied for quantitative structure actions relationships (QSAR) and quantitative structures property relationships (QSPR). Topological co-indices are topological descriptors which are considered the noncontiguous vertex set. We study the accompanying some renowned topological co-indices: first and second Zagreb co-indices, first and second multiplicative Zagreb co-indices and the F-coindex, and some other degree-based indices of the co-indices of ceria oxide.

Porous materials, for example, metalnatural structures (MOFs) and their discrete partners metalnatural polyhedra (MOPs), that are built from coordinatively unsaturated inorganic hubs show incredible potential for application in gas adsorption/partition cycles, catalysis, and arising openings in hardware, optics, detecting, and biotechnology. A well-known hetero-bimetallic metalorganic polyhedra of this discrete partners metalnatural polyhedra (MOPs) class is cuboctahedral bi-metallic stricture. In this paper, we discuss the stricture of Hetero-bimetallic metalorganic polyhedra (cuboctahedral bi-metallic). Also, we computed the topological indices based on the degree of atoms in this cuboctahedral bi-metallic structure.

Topological index (TI) is a numerical invariant that helps to understand the natural relationship of the physicochemical properties of a compound in its primary structure. George Polya introduced the idea of counting polynomials in chemical graph theory and Winer made the use of TI in chemical compounds working on the paraffin's boiling point. The literature of the topological indices and counting polynomials of different graphs has grown extremely since that time. Metal-organic network (MON) is a group of different chemical compounds that consist of metal ions and organic ligands to represent unique morphology, excellent chemical stability, large pore volume, and very high surface area. Working on structures, characteristics, and synthesis of various MONs show the importance of these networks with useful applications, such as sensing of different gases, assessment of chemicals, environmental hazard, heterogeneous catalysis, gas and energy storage devices of excellent material, conducting solids, super-capacitors and catalysis for the purification, and separation of different gases. The above-mentioned properties and physical stability of these MONs become a most discussed topic nowadays. In this paper, we calculate the M-polynomials and various TIs based on these polynomials for two different MONs. A comparison among the aforesaid topological indices is also included to represent the better one.

Random structure plays an important role in the composition of compounds, and topological index is an important index to measure indirectly the properties of compounds. The Zagreb indices and its revised versions (or redefined versions) are frequently used chemical topological indices, which provide the theoretical basis for the determination of various physical-chemical properties of compounds. This article uses the tricks of probability theory to determine the reduced second Zagreb index and hyper-Zagreb index of two kinds of vital random graphs: G ( n , p ) and G ( n , m ).

In the modern era of the chemical science, the chemical graph theory has contributed significantly to exploring the properties of the chemical compounds. Currently, the computation of the topological indices is one of the most active directions of the research in the area of the chemical graph theory. The main feature of the study of the topological indices is its its ability of predicting the various physio-chemical properties. In this article, we compute several degree-based topological indices for the caboxy-terminated dendritic macromolecule. We compute Harmonic index, atom-bond connectivity index, geometric arithmetic index, sum connectivity index, inverse sum index, symmetric division degree, and Zagreb indices for caboxy-terminated dendritic macromolecule. The obtained results have potential to predict biochemical properties such as viscosity, entropy, and boiling point.

A vast amount of information about distance based graph invariants is contained in the Hosoya polynomial. Such an information is helpful to determine well-known distance based molecular descriptors. The Hosoya index or Z -index of a graph G is the total number of its matching. The Hosoya index is a prominent example of topological indices, which are of great interest in combinatorial chemistry, and later on it applies to address several chemical properties in molecular structures. In this article, we investigate Hosoya properties (Hosoya polynomial, reciprocal Hosoya polynomial and Hosoya index) of the commuting graph associated with an algebraic structure developed by the symmetries of regular molecular gones (constructed by atoms with regular atomic-bonding).

Grid implementation is a principal unit in electrical and electronic engineering but it depends on the domain of these projects. For example, depending on the grid and the signal processing in that fields of electronic and electrical engineering, such as more abstract mathematics in signal conversion and e-transmission theory griding, etc. Provides transmission through grid nodes. Graph theory is very useful in research fields. As topological indices, there are more actual numbers associated with chemical composition complaints connected to the chemical grid with physical and chemical properties and reactions. In this paper, we expand the work to interconnected grid and examine the first Zagreb, the second Zagreb, Randic, sum-connectivity, harmonic, geometric, and atom bond connectivity exponents of hierarchical hypercube network based on vertex-edge and edge-vertex degree.

The Wiener index, due to its many applications is considered to be one of very important distance-based index. But the Padmaker-Ivan (PI) index is kind of the only distance related index linked to parallelism of edges. The PI index like other distance related indices has great disseminating power. The index was firstly investigated by Khadikar et al. (2001), they have probed the chemical applications of the PI index. They proved that the proposed PI index correlates highly with the physicochemical properties and biological activities of a large number of diverse and complex chemical compounds and the Wiener and Szeged indices. Recently, the vertex Padmarkar-Ivan (PI v ) index of a chemical graph G was introduced as the sum over all edges uv of a molecular graph G of the vertices of the graph that are not equidistant to the vertices u and v . In this paper, the vertex PI v index of certain triangular tessellation are computed by using graph-theoretic analysis, combinatorial computing, and edge-dividing technology.

Sierpiński graphs are family of fractal nature graphs having applications in mathematics of Tower of Hanoi, topology, computer science, and many more diverse areas of science and technology. This family of graphs can be generated by taking certain number of copies of the same basic graph. A topological index is the number which shows some basic properties of the chemical structures. This article deals with degree based topological indices of uniform subdivision of the generalized Sierpiński graphs S ( n , G ) and Sierpiński gasket S n . The closed formulae for the computation of different kinds of Zagreb indices, multiple Zagreb indices, reduced Zagreb indices, augmented Zagreb indices, Narumi-Katayama index, forgotten index, and Zagreb polynomials have been presented for the family of graphs.