Abstract Silacyclopentadienes (siloles) are currently of great interest because of their intriguing aggregation-induced emission (AIE) characteristics. In this work, abnormally AIE phenomena were observed from silyl- and hydrogen-substituted siloles respectively. We propose silyl-substituent and hydrogen atom effects to explain this via both experiments and theoretical calculations. It was discovered that trimethylsilyl substituents destroyed the p-interactions with the silole core and resulted in the non-fluorescence. Additionally, 1-chloro-1-H-2,3,4,5-tetraphenylsilole featuring strong fluorescences in both solid and solution states with high fluorescence quantum yields represents a new potential photoelectric material. This work not only reports the silole with strong fluorescences in both solid and solution states for the first time but also contributs to enrich the AIE research of siloles. Graphical Abstract

Abstract The quantitative structures activity relationships (QSAR) and quantitative structures property relationships (QSPR) between the chemical compounds are studied with the help of topological indices (TI’s) which are the fixed real numbers directly linked with the molecular graphs. Gutman and Trinajstic (1972) defined the first degree based TI to measure the total π-electrone energy of a molecular graph. Recently, Ali and Trinajstic (2018) restudied the connection based TI’s such as first Zagreb connection index, second Zagreb connection index and modified first Zagreb connection index to find entropy and accentric factor of the octane isomers. In this paper, we study the modified second Zagreb connection index and modified third Zagreb connection index on the T-sum (molecular) graphs obtained by the operations of subdivision and product on two graphs. At the end, as the applications of the obtained results for the modified Zagreb connection indices of the T-sum graphs of the particular classes of alkanes are also included. Mainly, a comparision among the Zagreb indices, Zagreb connection indices and modified Zagreb connection indices of the T-sum graphs of the particular classes of alkanes is performed with the help of numerical tables, 3D plots and line graphs using the statistical tools.

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.

Abstract Structural data of cis-Pt(η2-P2L)(XL)2 (X = Ge or Te), cis-Pt(η2-P2L)(η2-X2L) (X = As, Ge or Te) and trans-Pt(η2-P,TeL)2 were classified and analyzed. The chelating ligands create varieties of metallocyclic rings, which open in the sequence: 83.1° (GeGeGe) < 83.8° (AsC2As) < 86.2° (PC2P) < 88.5° (PC2Te) < 89.7° (PC3P) ~ 89.7° (GeGe2Ge). The structural data are compared and discussed with the complexes of an inner coordination spheres Pt(η2-P2L)(XL)2 (X = O, N, CN, B, Cl, S, Se, Si, Br or I), Pt(η2-P2L)(η2- X2L) (X = O, N, S, Se or Si), and Pt(η2-P,SiL)2.

The syntheses of three different amidinosilanes of the type Me2Si[N=C(Ph)R]2 with R = pyrrolidino, morpholino, and diethylamino and one derivative with the composition R2Si[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 29Si NMR signals.

Abstract A palladium complex of a dendrimer type ligand of aminoethylacrylamide immobilized onto the mesoporous channels of MCM-41 with magnetic core was prepared and characterized using various techniques such as XRD, TEM, BET, FT-IR, TGA, and VSM. The prepared nanostructured material was found as a magnetically recoverable catalyst for Heck reaction of aryl halides and vinylic C–H. The catalyst is easily recoverable with an external magnet and is reusable with different leaching amounts depending to loading of Pd. A hot filtration test was also performed and gave evidence that Palladium in heterogeneous samples can dissolve and then redeposit on the surface of the support material. Graphical Abstract

Abstract In this review are analyzed and classified crystallographic and structural parameters of P(0)P3, Pt(0) P4 and Pt(II)P4 derivatives – distortion isomers. Some of the isomers are differing not only by degree of distortion but also by crystal class. There are three types of organo-phosphines which build up the respective geometry about the platinum atoms. In Pt(0)P3 a distorted trigonal planar geometry is build up by three monodentate PPh3 ligands. In Pt(0)P4 a tetrahedral geometry with various degree of distortion is build up by a pair of homo-bidentate ligands. In Pt(II)P4 isomers a square-planar geometries with various degree of distortion are build up by bidentate-P,P’donor ligands, (except one example of isomers, where a tetradentate is involved). The bidentate-P,P’-donor ligands form: four-(PNP,PCP), five-(PC2P) and six-(PC3P) metallocyclic rings. The tetradentate forms five-(PC2P). There are some cooperative effects between Pt–P bond distances and the metallocyclic rings, and at the same time a distortion of the respective geometry increases.

Abstract The crystal structures of the salts [Li(1,2-F2C6H4)] [B(C6F5)4] (1) and Cs[B(C6F5)4] (2) comprise six Li···F contacts (1.965(3) − 2.312(3) Å) and twelve Cs···F contacts (3.0312(1) − 3.7397(2) Å), respectively, which are significantly shorter than the sum of van der Waals radii (3.29 and 4.90 Å).

Abstract In current study, the effect of various organic substances as bulking agents (BAs) including wheat straw, pistachio hull wastes, and tree leaves at different levels (10, 25, 45% v/v) were investigated on total concentration and chemical forms of Cu, Pb, Cr, and As in sewage sludge (SS) compost prepared by windrow method. According to the results, the composting process (with/without BAs), due to losses of SS mass and volume, increased the total concentration of heavy metals (HMs) compared to the un-composted SS sample (RSS). Evaluation of HMs chemical forms in prepared compost sample without BAs application (CSS) showed that the composting process reduced the mobility factor of As (from 28% to 20%), Pb (from 11.6% to 9.3%), and Cr (from 14.5% to 9.2%) compared to the RSS. Application of three BAs considerably decreased the mobility factor of As (17.5-18.8%), Pb (4.8-7.9%), and Cr (1.4-6.8%) compared to CSS and RSS. Changes of Cu mobility in prepared compost samples showed an unclear trend, however in some treatments, due to transferred organic fraction into exchangeable and carbonate fractions, increasing of this factor was obvious. Generally, the composting appeared to reduce As, Pb, and Cr availability by stabilizing the three metals and making them more stable and less mobile. In addition, the BAs application effect on HMs behavior of SS compost samples were so different and no specific kind of BAs can be recommended as a superior BAs in SS composting process.

Abstract Three types of ladder-like organostannoxanes, [C5H4N(p-CO2)]2[Bu2Sn]4(μ 3-O)2(μ 2-OH)2 (1), [Ph2CHCO2]4[Bu2Sn]4(μ 3-O)2 (2), and [(p-NH2)-C6H4-CO2]2[Bu2Sn]4(μ 3 -O)2(μ 2 -OH)2 (3), have been synthesized and characterized using elemental analyses, Fourier-transform infrared spectroscopy, nuclear magnetic resonance (1H, 13C) experiments, and, for 1 and 2, single-crystal X-ray diffraction analysis. X-Ray diffraction discloses that complexes adopt tetranuclear tin(iv) ladder-like structures containing two (1) or four (2) deprotonated ligands. The essential difference between their molecular structures is that in 2 there are four carboxylate ligands, while in 1 and 3 there are two. The crystal structure of 1 reveals them to be a tetranuclear structure containing a three-rung-staircase Sn4O4 core. The Sn4O4 cluster consists of a ladder of four Sn2O2 units. For 2, the structure is a tetranuclear centrosymmetric dimer of an oxoditin unit having a central four-member ring. In this complex, the central Sn2O2 core is fused with two four-member and two six-member rings. In the structures, there are two types of tin ions arranged in distorted trigonal bipyramid geometry or octahedron geometry. A series of O–H⋯N, C–H⋯O, and C–H⋯π intermolecular hydrogen bonds in these complexes play an important function in the supramolecular, or two-dimensional network structures are formed by these interactions.

Two [2-((L)-menthoxycarbonyl)ethyl]diphenyltin halides, (L)-MenOCOCH2CH2SnXPh2 (X=Cl, 1; I, 2), have been synthesized and characterized by means of elemental analysis, FT-IR, NMR (1H, 13C, and 119Sn) spectroscopy, and X-ray single crystal diffraction. The tin atoms in 1 and 2 are both five-coordinated and possess the [C3SnOX] (X=Cl and I) trigonal bipyramidal environment with the trigonal plane defined by the three carbon atoms and the axial positions occupied by the halogen atom and internal carbonyl oxygen. There is a five-membered chelate ring in 1 and 2 with the Sn-O distance being 2.4781(16) and 2.512(2) Å, respectively.

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 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.

Abstract Dissolution of [(μ-Me2CO)3(NaTp*)2] (1) (Tp* = hydrido-tris(3,5-dimethyl-1-pyrazolyl)borate) in DMSO at room temperature leads to the growth of colourless crystals characterized as the new salt [Na2Tp*(μ-Me2SO)3(Me2SO)3] [NaTp*2] (2). 2 crystallized in the trigonal space group R3 with Z = 3, a = 14.1227(2) Å, b = 14.1227(10) Å, c = 33.9685(2) Å, and V = 5867.35(17) Å3. Interestingly, anion and cation of 2 both contain the Tp* ligand. Moreover, the cationic moiety highlights an unusual sodium atom hexacoordinated by six DMSO molecules acting as O-bonded ligands. Three of which exhibit a bridging coordination mode and three are in terminal position. To the best of our knowledge, the framework of [Na2Tp*(μ-Me2SO)3(Me2SO)3] is unprecedented.

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 ).

Abstract A new 2D dibutyltin coordination polymer with 3,5-dinitrosalicylate and 4,4’-bipyridine ligands, [{Bu2Sn(3,5–(NO2)2–2–OC6H2COO)}2(4,4’-bpy)]n (1), has been synthesized and characterized both spectroscopically (IR, 1H, 13C, and 119Sn NMR) and a single-crystal X-ray diffraction analysis. The coordination geometry of tin atom in 1 is a distorted octahedron. 3,5-Dinitrosalicylate as doubly charged anion ligand adopts chelating-bridging mode to coordinate to tin atoms, and 4,4’-bipyridine further bridges the tin atoms to form a 2D herringbone-like network structure containing the 34-membered hexa-nuclear macrocycles.

Abstract tHPA-ZSM-5 nanocomposites as a superior catalyst have been applied for the synthesis of indenopyrazolones through a three-component reaction of phenylhydrazine, benzaldehydes, and indan-1,2,3-trione at room temperature in acetonitrile. The zeolite catalyst has been characterized by X-ray diffraction, field emission scanning electronic microscopes, Fourier transform infrared, energy-dispersive spectroscopy, thermogravimetric analysis, and N2-adsorption analysis. The various aromatic aldehydes can be utilized in this method. These results showed that aromatic aldehydes with electron-withdrawing groups reacted faster than aldehydes with electron-releasing groups. Experimental simplicity, excellent yields in short reaction times, reusability of the catalyst, and low catalyst loading are some of the substantial features of this method.

In this study, three types of ferrites nanoparticles including CoFe 2 O 4 , NiFe 2 O 4 , and ZnFe 2 O 4 were synthesized by microwave-assisted hydrothermal method. The X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were employed to analyze synthesized nanoparticles and fabricated membranes. The morphology of membrane surface was investigated by surface images. The ability of ferrite nanoparticles was evaluated to the separation of sodium salt and heavy metals such as Cr 2+ , Pb 2+ , and Cu 2+ from aqueous solutions. The modified membrane showed the enhancement of membrane surface hydrophilicity, porosity, and mean pore size. The results revealed a significant increase in pure water flux: 152.27, 178, and 172.68 L·m −2 ·h −1 for PES/0.001 wt% of CoFe 2 O 4 , PES/0.001 wt% NiFe 2 O 4 , and PES/0.001 wt% ZnFe 2 O 4 NPs, respectively. Moreover, Na 2 SO 4 rejection was reached 78% at 0.1 wt% of CoFe 2 O 4 NPs. The highest Cr (II) rejection obtained 72% for PES/0.001 wt% of NiFe 2 O 4 NPs while it was 46% for the neat PES membrane. The Pb(II) rejection reached above 75% at 0.1 wt% of CoFe 2 O 4 NPs. The Cu(II) rejection was obtained 75% at 0.1 wt% of CoFe 2 O 4 NPs. The ferrite NPs revealed the high potential of heavy metal removal in the filtration membranes.

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.

Abstract This study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.