Ti Complexes Research Articles

PCP Pincer Complexes of Titanium in the +3 and +4 Oxidation States.

Ti(IV) and Ti(III) complexes using the tBuPCP ligand have been synthesized (tBuPCP = C6H3-2,6-(CH2PtBu2)2). The [tBuPCP]Li synthon can be reacted with TiCl4(THF)2 to form (tBuPCP)TiCl3 (1) in limited yields due to significant reduction of the titanium synthon. The Ti(III) complex (tBuPCP)TiCl2 (2) has been further characterized. This can have half an equivalent of halide abstracted to form [{(tBuPCP)TiCl}2{μ-Cl}][B(C6F5)4] (3) and can also be methylated, forming (tBuPCP)TiMe2 (4). All the Ti(III) complexes have been characterized using EPR and X-ray crystallography, giving insight into their electronic structures, which are further supported by DFT calculations.

A14 TRANSABDOMINAL BOWEL ULTRASOUND AND CLINICAL OUTCOMES OVER ONE YEAR IN CHILDREN WITH NEWLY DIAGNOSED CROHN’S DISEASE

Abstract Background Transabdominal bowel ultrasound (TABUS) is an emerging non-invasive tool for monitoring inflammatory bowel disease (IBD). Its use is particularly increasing in pediatric IBD, given the need for anesthesia during endoscopy. The assessment of TABUS in pediatric IBD has been limited to small numbers of patients with no long-term follow-up. Purpose To describe TABUS findings and its relationship with clinical, biochemical, and endoscopic assessments in pediatric patients with Crohn’s disease up to one year post-diagnosis. Method Patients (0-18 years) with suspected IBD were prospectively enrolled through the Edmonton Pediatric IBD Clinic. Those with Crohn’s disease were included. Patients underwent repeated TABUS, clinical assessments, blood work, fecal calprotectin (FCP) (baseline, 1-, 3-, 6-, 12-months), and endoscopy (baseline and 6-12 months). The weighted Pediatric Crohn’s Disease Activity Index (wPCDAI), Simple Endoscopic Score for Crohn’s Disease (SES-CD; rectum excluded), and Simple Ultrasound Activity Score for Crohn’s Disease (SUS-CD; rectum excluded) were used. Remission was defined as FCP<250mg/kg, CRP<4mg/L, wPCDAI<12, no upcoming surgery, and SES-CD score ≤2 for any bowel segment. Result(s) Fifty-six patients (68% male), median age 12.5 years (range 6-17), were followed for 6 months. Forty (71%) were followed up to 12 months. Median TABUS bowel wall thickness (BWT) and SUS-CD total scores improved in all bowel segments over time. SUS-CD total scores significantly correlated with SES-CD (baseline, 6-, 12-months), wPCDAI (baseline, 1-, 6-, 12-months), CRP (baseline, 1-, 3-, 6-months), ESR (baseline, 1-, 3-, 6-, 12-months), and FCP (baseline, 1-, 6-, 12-months) (rho ranged 0.302-0.732, p<0.05). Patients in remission had sustained significantly thinner BWT of their most affected bowel segment (Figure 1) starting at 1-month (median 3.1mm (IQR 2.7-3.7) vs. 4.1mm (IQR 2.9-5.6; p<0.05), and sustained significantly lower SUS-CD total scores starting at 6 months (median 0 (IQR 0-1) vs. median 2 (IQR 1-3); p<0.05). Seven patients had surgery (n=7/7 ileocecal, n=2/7 jejunal resection). All 7 patients had complex TI disease (n=6 strictures, n=1 long-segment disease >25cm) and proximal small bowel disease (n=2/2) on TABUS. Those with baseline ultrasound findings of a stricture with upstream bowel dilatation (n=7/56) had increased odds (OR=288, p<0.01) and relative risk (RR=42, p<0.01) of needing surgery (n=6/7 with baseline obstructive findings, n=1/49 without) within the first year. Image Conclusion(s) TABUS had significant correlations with clinical, biochemical, and endoscopic markers of Crohn’s disease activity in pediatric patients over one year. Bowel wall thickness of the most affected bowel segment is a helpful measurement, becoming significantly thinner as soon as 1-month post-diagnosis in those who obtain remission. Baseline findings of bowel narrowing and upstream dilation increase the odds and relative risk of needing surgery in the first year. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

Direct Incorporation of Dinitrogen into an Aliphatic C-H Bond.

The activation of dinitrogen (N2) and direct incorporation of its N atom into C-H bonds to create aliphatic C-N compounds remains unresolved. Incompatible conditions between dinitrogen reduction and C-H functionalization make this process extremely challenging. Herein, we report the first example of dinitrogen insertion into an aliphatic Csp3-H bond on the ligand scaffold of a 1,3-propane-bridged [N2N]2--type dititanium complex. Mechanistic investigations on the behaviors of dinuclear and mononuclear Ti complexes indicated the intramolecular synergistic effect of two Ti centers at a C-N bond-forming step. Computational studies revealed the critical isomerization between the inactive side-on N2 complex and the active nitridyl complex, which is responsible for the Csp3-H amination. This strategy maps an efficient route toward the future synthesis of aliphatic amines directly from N2.

Ti-decorated nitrogen-rich BeN4 monolayer for reversible hydrogen storage: DFT investigations

The metal-decorated two-dimensional materials have the potential to be considered as onboard hydrogen storage materials, as they have a high surface area and fast kinetics. Here, the application of titanium atom (Ti) decoration on the nitrogen-rich BeN4 monolayer for hydrogen storage is studied by means of Density Functional Theory (DFT). BeN4 is made up of five and six-membered rings and has been synthesized using high-pressure nanofabrication in the recent past. The binding energy of the Ti-decorated BeN4 monolayer comes out to be −2.04 eV indicating that an energetically stable complex is formed after metal decoration. The spin-polarized partial density of states (PDOS) implies that semimetal BeN4 becomes magnetic after Ti decoration. The charge transfer analysis validates transfer of charge from the Ti metal atom toward the BeN4 monolayer. The Ti-decorated BeN4 (BeN4 + Ti) can bind seven hydrogen molecules via Kubas interactions with average adsorption energy and desorption temperature of −0.36 eV/H2 and 512 K, correspondingly satisfying DOE’s criteria. The ab initio molecular dynamics (AIMD) simulations ensure the structural integrity of the BeN4 + Ti complex at 300 K. The high diffusion energy barrier reduces the probability of metal–metal clustering formation. The storage capacity of the BeN4 + Ti complex comes out to be 14.21 gravimetric wt% of hydrogen. The present electronic and molecular level study signifies that the Ti-decorated nitrogen-rich BeN4 monolayer has the potential to fulfill the requirements to be considered as an energy storage material.

Synthesis of Ti Complexes Supported by an ortho-terphenoxide Ligand and their Applications in Alkyne Hydroamination Catalysis.

The synthesis of a series of Ti complexes of an aryl-linked bis-phenoxide ligand, 3,3''-di-tert-butyl-5,5''-dimethyl-[1,1':2',1''-terphenyl]-2,2''-bis(olate), (TPO)H2, is reported. This ortho-linked terphenyl ligand builds on previously reported meta- and para- linked terphenyl based ligands, completing the isomeric series of terphenoxide ligands. The 4-coordinate (TPO)Ti(NMe2)2 is an active catalyst for alkyne hydroamination with a variety of arylamines, revealing good regioselectivity in reactions with unsymmetric alkynes. Terminal alkynes such as phenylacetylene undergo additional insertion reactions with the key azatitanacyclobutene intermediates, providing further evidence that Ti aryloxide complexes are susceptible to this further reactivity.

Enhanced piezo-photocatalytic properties of new salophen based Ti (IV) complexes

Enhanced piezo-photocatalytic properties of new salophen based Ti (IV) complexes

Carboxy‐thioether‐thiolato titanium–graphene oxide nanocomposite as drug delivery system for targeted cancer therapy: Design, characterization, bovine serum albumin binding study, and biological evaluation

Carboxy‐thioether‐thiolato Ti (IV) complex (TiCTT) and its graphene oxide nanocomposite (GO–TiCTT) were prepared and characterized for the development of novel compounds with enhanced antibacterial and anticancer capabilities, and the loading ratio of TiCTT was found to be approximately 33.3%. Thermal studies and zeta potential revealed that GO–TiCTT is more stable than GO, whereas SEM and TEM revealed efficient TiCTT adsorption on the surface of GO. Various biophysical procedures were used to investigate the interactions of CTT, TiCTT, GO, and GO–TiCTT nanocomposite with bovine serum albumin (BSA). The results revealed that the intrinsic fluorescence quenching of BSA resulting from low concentrations was caused by the formation of stable BSA adducts via the binding interaction with BSA. The stable adduct had a stoichiometry of 1:1 and binding constants (Kb) in the order of 105 M1 at 310 K for CTT, TiCTT, and GO–TiCTT, indicating a very strong binding interaction with BSA. Based on the sign and magnitude of the free energy change (G#), it can be concluded that the binding process with BSA was spontaneous, with van der Waals force and hydrogen bonding interaction as the main interaction forces. A combined quenching process was observed at higher concentrations of these compounds. Using the stopped‐flow technique, the TiCTT release behavior from the nanocomposite was investigated, and the GO–TiCTT system demonstrated pH‐responsive and sustained drug release. Furthermore, when compared to GO, CTT, TiCTT, and GO–TiCTT nanocomposite demonstrated good antibacterial activity against both Gram‐positive and Gram‐negative bacteria. They also have higher cytotoxicity against HepG2 human liver cancer cells than CTT. The calculated BSA‐binding constants matched the antimicrobial and cytotoxic results well. As a result, this research could lead to the development of a drug delivery system.

Titanium(IV) Surface Complexes Bearing Chelating Catecholato Ligands for Enhanced Band-Gap Reduction

Protonolysis reactions between dimethylamido titanium(IV) catecholate [Ti(CAT)(NMe2)2]2 and neopentanol or tris(tert-butoxy)silanol gave catecholato-bridged dimers [(Ti(CAT)(OCH2tBu)2)(HNMe2)]2 and [Ti(CAT){OSi(OtBu)3}2(HNMe2)2]2, respectively. Analogous reactions using the dimeric dimethylamido titanium(IV) (3,6-di-tert-butyl)catecholate [Ti(CATtBu2-3,6)(NMe2)2]2 yielded the monomeric Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 and Ti(CATtBu2-3,6)[OSi(OtBu)3]2(HNMe2)2. The neopentoxide complex Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 engaged in further protonolysis reactions with Si-OH groups and was consequentially used for grafting onto mesoporous silica KIT-6. Upon immobilization, the surface complex [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[KIT-6] retained the bidentate chelating geometry of the catecholato ligand. This convergent grafting strategy was compared with a sequential and an aqueous approach, which gave either a mixture of bidentate chelating species with a bipodally anchored Ti(IV) center along with other physisorbed surface species or not clearly identifiable surface species. Extension of the convergent and aqueous approaches to anatase mesoporous titania (m-TiO2) enabled optical and electronic investigations of the corresponding surface species, revealing that the band-gap reduction is more pronounced for the bidentate chelating species (convergent approach) than for that obtained via the aqueous approach. The applied methods include X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and solid-state UV/vis spectroscopy. The energy-level alignment for the surface species from the aqueous approach, calculated from experimental data, accounts for the well-known type II excitation mechanism, whereas the findings indicate a distinct excitation mechanism for the bidentate chelating surface species of the material [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[m-TiO2].

Titanium complexes affect Bacillus subtilis biofilm formation.

Biofilms are surface or interface-associated communities of bacterial cells, embedded in a self-secreted extracellular matrix (ECM). Cells in biofilms are 100-1000 times more resistant to antibiotic treatment relative to planktonic cells due to various reasons, including the ECM acting as a diffusion barrier to antibiotic molecules, the presence of persister cells that divide slowly and are less susceptible to cell-wall targeting drugs, and the activation of efflux pumps in response to antibiotic stress. In this study we tested the effect of two titanium(iv) complexes that have been previously reported as potent and non-toxic anticancer chemotherapeutic agents on Bacillus subtilis cells in culture and in biofilm forming conditions. The Ti(iv) complexes tested, a hexacoordinate diaminobis(phenolato)-bis(alkoxo) complex (phenolaTi) and a bis(isopropoxo) complex of a diaminobis(phenolato) "salan"-type ligand (salanTi), did not affect the growth rate of cells in shaken cultures, however they did affect biofilm formation. Surprisingly, while phenolaTi inhibited biofilm formation, the presence of salanTi induced the formation of more mechanically robust biofilms. Optical microscopy images of biofilm samples in the absence and presence of Ti(iv) complexes suggest that Ti(iv) complexes affect cell-cell and/or cell-matrix adhesion, and that these are interfered with phenolaTi and enhanced by salanTi. Our results highlight the possible effect of Ti(iv) complexes on bacterial biofilms, which is gaining interest in light of the emerging relations between bacteria and cancerous tumors.

Технология изготовления и свойства высокотемпературных пьезокерамических материалов на основе фаз системы (1 – у)(Bi0,8Ba0,2)Fe0,8Ti0,2O3 – у(Ba0,85Ca0,15)Ti0,90Zr0,10O3

In technology, using as precursors Fe(III) and Bi(III) nitrates, peroxo-nitrate complexes Ti(IV) and Zr(IV), as well as barium and calcium hydroxides, ultrafine powders of the (1 – у)Bi0.8Ba0.2Fe0.8Ti0.2O3 – уBa0.85Ca0.15Ti0.9Zr0.1O3 (у = 0,05 – 0,30). To reduce the electrical conductivity of ceramic samples made from these powders, the basic phases were alloyed with manganese compounds. To increase the d33 values of the piezoelectric elements, as well as to increase their operating temperature, a special sintering regime involving air hardening of the ceramic samples was used. The best samples of piezoceramics produced by the proposed technology have a Curie temperature above 550 °C and longitudinal piezoelectric modulus (standard conditions) values d33 ≥ 125 pC/N and their operating temperature reaches 340 – 350 °C.

The use of titania polymorphs as indicators of mesodiagenesis during hydrocarbon charge

Authigenic titania (TiO2) minerals are observed in the Upper Jurassic-Lower Cretaceous pro-deltaic reservoir sandstones of the Scotian Basin. Although diagenetic rutile is rare, relatively large amounts of diagenetic anatase and brookite are present. Anatase is mostly early diagenetic whereas brookite is usually late diagenetic and is abundant in reservoir sandstones above the free-water level. The availability and mobility of Ti during late diagenesis is attributed to the dissolution of Ti-bearing minerals enhanced by Ti complexes formed from hydrocarbon-rich and highly saline fluids. This study suggests that the precipitation of late diagenetic brookite, rather than anatase or rutile, may be due to the incorporation of Fe and V during hydrocarbon charge and the presence of Cl− in circulating fluids. In addition, the chemical composition, timing and distribution of the diagenetic titania polymorphs relative to other diagenetic minerals further constrains the overall paragenetic evolution of the basin, and thus illustrates the relationship between titania minerals, hydrocarbon charge and fluid conditions in the basin.

Synthesis, characterization, lipoxygenase, and tyrosinase inhibitory activities of non- cytotoxic titanium(III) and (IV) hydrazide complexes

ABSTRACT. Ti(III) and (IV) hydrazide complexes were synthesized, characterized, and screened for their tyrosinase and lipoxygenase inhibitory and cytotoxic activities. The geometry of Ti(III) hydrazide complexes is tentatively assigned as octahedral. Magnetic moments were found around 1.7 B.M. and electronic spectral transition in the range of 495-518 nm. Evaluation of Ti(IV) and Ti(III) hydrazide complexes for tyrosinase and lipoxygenase inhibitory activities revealed varying inhibition potential. Hydrazide ligands were inactive against tyrosinase, while significant activity was observed against lipoxygenase (LOX). Good to moderate inhibition activity was observed by Ti(IV) and Ti(III) hydrazide complexes against both enzymes. At the same time, promising results were obtained for Ti(IV) hydrazide complexes against tyrosinase enzymes suggesting their broad application as tyrosinase inhibitors. Complex 4d possess negative inhibition, thus behaving as a tyrosinase activator. The docking results showed a good correlation between complex experimental activities and binding energies. Cytotoxic investigation revealed the non-toxicity of complexes against normal cells.
 
 KEY WORDS: Titanium(III) and titanium(IV) hydrazide complex, Tyrosinase, Lipoxygenase, Inhibition, Molecular docking, Cytotoxicity
 
 Bull. Chem. Soc. Ethiop. 2023, 37(2), 315-333. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i2.6

Targeted construction of a three-dimensional metal covalent organic framework with spn topology for photocatalytic hydrogen peroxide production

A 3D metal covalent organic framework (TiCOF-spn) with unreported spn topology was synthesized for photocatalytic H 2 O 2 production. This work expands the topology of the 3D COFs family and pioneers the application of metal-containing COFs in solar energy conversion. • Metal-containing units overcome the obstacle of limited polyhedral organic molecular for 3D COFs. • A 3D metal covalent organic framework (TiCOF-spn) possesses unreported spn topology. • TiCOF-spn pioneers the application of solar energy conversion with H 2 O 2 photocatalysis. To enrich the topology of three-dimensional covalent organic frameworks (3D COFs) is an appealing challenge. Till now, only 20 types of topologies have been achieved in 3D COFs because of the limited polyhedral building blocks. Herein, we report the first 3D titanium-based COF with spn topology (TiCOF-spn) through [6 + 3] imine condensation of a Ti(IV) complex with six aldehyde groups positioned in a trigonal antiprismatic arrangement and a planar triazine-based amine connector. Interestingly, TiCOF-spn contains two kinds of pores, that is, the linking of the tetrahedral cages by sharing vertices forms the truncated tetrahedral cages. By integrating the crystalline porous framework, photoactive titanium center and triazine component, TiCOF-spn shows strong visible light absorption and efficient photocatalytic activity for producing H 2 O 2 (489.94 μmol g −1 h −1 ). This work expands the topology of the 3D COFs family and pioneers the application of metal-containing COFs in solar energy conversion.

Effect of static annealing on superplastic behavior of a friction stir welded Ti-6Al-4V alloy joint and microstructural evolution during deformation

• A new combination process of FSW + static annealing + superplastic deformation was proposed for eliminate strain localization and the welded structure • Similar superplastic abilities were obtained by the BM and NZ with totally different structures • An optimized view on the classical Langdon theory was put forward in the field of superplasticity • The mechanisms of the spheroidization in the NZ and the equiaxed structure fragmentation in the BM were discussed • This study provides a new way to fabricate large-scale complex Ti alloy components Structural integration is one of the most critical developing directions in the modern aerospace field, in which large-scale complex components of Ti alloys are proposed to be fabricated via the method of welding + superplastic forming. However, the undesired strain localization appeared during superplastic deformation of the entire joint has largely hindered the development of this method. In our study, a combination process of friction stir welding (FSW) + static annealing + superplastic deformation was first time proposed to eliminate severe local deformation. To achieve this result, a fully fine lamellar structure was obtained in the nugget zone (NZ) via FSW, which was totally different from the mill-annealed structure in the base material (BM). After annealing at 900 °C for 180 min, the BM and NZ then exhibited the similar elongation of >500% and similar flow stress at 900 °C, 3 × 10 −3 s −1 , which was the precondition for achieving uniform superplastic deformation in the entire joint. Moreover, the different microstructures in the BM and NZ tended to become the similar equiaxed structure after deformation, which was the result of different microstructural evolution mechanisms in the NZ and BM. For the NZ, there was a static and dynamic spheroidization of the fully lamellar structure during the process, which could largely reduce the flow softening of the fully lamellar structure. For the BM, a new view of “Langdon-CRSS theory” (CRSS, critical resolved shear stress) was proposed to describe the fragmentation of the coarse equiaxed structure, which established the relationship between grain boundary sliding and intragranular deformation during deformation.

Effect of Permanent Magnet Stirring on Solidification of High‐Sulfur Micro‐Alloyed Steel under Different Magnetic Flux Densities

The effects of permanent magnet stirring (PMS) with different center magnetic flux densities (0, 850, 1450, and 1800 Gs) on the solidification process of high‐sulfur micro‐alloyed 49MnVS3 steel are investigated by analyzing the MnS precipitation, microstructure, and tensile properties. The results indicate that with an increase in the magnetic flux density, an enhanced turbulent flow is introduced to the melt, and the MnS precipitates are not limited by grain boundary and distributed randomly and uniformly in the steel. When the magnetic flux density of PMS increases from 0 to 1800 Gs, the mean length of MnS decreases from 6.8 to 2.9 μm, and the number density of MnS increases from 1562 to 2293 n mm−2. Meanwhile, the content of the intragranular ferrite (IGF) increases from 0.4% to 3.1%, and the ratio of IGF in the total ferrite increases significantly from 4.2% to 30.1%, due to the growing precipitation of finer MnS‐ (Nb, V, Ti) (C, N) complex inclusions after PMS that induces the formation of IGF. In addition, both the tensile strength and toughness of the steel are improved under PMS with enhanced magnetic flux densities, which is attributed to the increased small‐sized MnS precipitates and promotes the formation of IGF.

Isomerism in Hexacoordinate Ti(IV) and Zr(IV) Complexes with a Tetradentate ONNO‐Schiff Base Ligand

AbstractThe reactions of [(thf)2TiCl4] with sodiated 2,2’‐bis[2‐hydroxy‐3,5‐di(tert‐butyl)benzylideneamino]‐1,1’‐biphenyl (1 a) and 2,2’‐bis[2‐hydroxy‐3,5‐di(tert‐butyl)benzylideneamino]‐4,4’‐dimethyl‐1,1’‐biphenyl (1 b) yield the corresponding Ti complexes 2 a and 2 b. Similarly, 1 a reacts with [(thf)2ZrCl4] to the corresponding Zr derivative 3. For 2 a, a mixture of cis‐β and trans isomers were observed in solution whereas the Zr congener exclusively forms the cis‐α form. Quantum chemical calculations verify that these isomers are the preferred molecular structures. The crystal structures of cis‐β isomeric 2 a and cis‐α isomeric 3 have been determined. Metalation of 1 a with Ti(NMe2)4 yields 2,2’‐bis[(2‐oxido‐3,5‐di(tert‐butyl)phenyl)‐dimethylaminomethylamino]‐1,1’‐biphenyl titanium(IV) (4) with a hexadentate ligand.

Effect of Activator and Outgoing Ligand Nature on the Catalytic Behavior of Bis(phenoxy-imine) Ti(IV) Complexes in the Polymerization of Ethylene and Its Copolymerization with Higher Olefins.

A series of bis(phenoxy-imine) (FI) titanium(IV) and zirconium(IV) complexes have been synthesized. The effect of the nature of the activator (MAO, combinations EtnAlCl3-n + Bu2Mg and iBu3Al + [Ph3C]+[B(C6F5)4]−) on the catalytic activity and properties of the resulting polymers was studied. It was found that Ti-Fi complexes, despite the nature of the outgoing ligands (Cl or iPrO) in the presence of Al/Mg activators, effectively catalyze the polymerization of ethylene (with the formation of UHMWPE); copolymerization of ethylene with 1-octene (with the formation of ultra-high molecular weight copolymers); and the ternary copolymerization of ethylene, propylene and 5-vinyl-2-norbornene (with the formation of polyolefin elastomers). It has been shown that Zr-FI complexes are not activated by these Al/Mg compositions. The resulting UHMWPE can be processed by a solventless method into high-strength and high-modulus oriented films; however, their mechanical characteristics do not exceed those obtained using MAO.

Going Up the Ladder: Stacking Four 4,4'-Bipyridine Moieties within a Ti(IV)-Based Tetranuclear Architecture.

Biphenol-based ligands have proven their ability to bind titanium(IV) centers and generate sophisticated self-assembled structures in which auxiliary nitrogen ligands often complete the coordination sphere of the metal and improve stability. Here, a central 4,4'-bipyridine, which acts as both a spacer and a source of monodentate nitrogen to complete the coordination sphere of the Ti(IV) complex, was incorporated within two bis-2,2'-biphenol strands, 3H4 and 4H4. Both proligands possess structural features that are well adapted to form self-assembled structures built from titanium-oxygen-nitrogen units; however, their different degrees of torsional freedom strongly influenced the nuclearity of the complexes formed. The presence of a phenyl spacer between the bipyridine and the biphenol moieties of 3H4 provided enough flexibility for the ligand to wrap around one titanium(IV) center to form a mononuclear complex Ti(3)(DMF)2 in the presence of dimethylformamide (DMF). Assembly of the more rigid ligand 4H4 with Ti(OiPr)4 afforded a tetranuclear complex Ti4(4)2(4H)2(OEt)2 containing four stacked 4,4'-bipyridine units as shown by the X-ray structure of the complex. Density functional theory studies suggested that the assembly of this tetrametallic complex involves a dimetallic intermediate with TiO6 nodes that is converted to the thermodynamically stable tetranuclear complex with two TiO6 nodes and two TiO5N units with enhanced covalent character.

Modification of Nonmetallic Inclusions by Ti and La Complex Treatment in High‐Al Transformation‐Induced Plasticity Steel

The effect of Ti and La complex treatment on the formation and evolution of inclusions in high‐Al transformation‐induced plasticity steel is investigated by laboratory experiments and thermodynamic calculations, with consideration given to the amount of La added and the sequence of the addition of Ti. The main inclusions are Al2O3 and AlN inclusions before the Ti and La additions. The AlN inclusions are transformed into TiN inclusions with the addition of 0.1 wt% Ti. After the subsequent addition of 0.007 wt% La, the main inclusions are LaAlO3, La2O2S, and TiN. With the addition of 0.06 wt% La to molten steel, the main inclusions are La2O2S, La2S3, and TiN. La may prevent the precipitation of TiN inclusions. Different addition sequences of Ti and La result in the same types of inclusions, with higher La addition. In the case of La addition before Ti, Ti can restrain the formation of La‐containing inclusions, and the number density of inclusions increases.

Density Functional Study of the adsorption behavior of 6-mercaptopurine on Primary, Si, Al and Ti doped C60 fullerenes

C60 fullerenes are often used as drug carriers because of their unique geometric structure and electronic properties.To investigate whether C60 fullerenes can be used as a drug delivery system for 6-mercaptopurine (6MP), we calculated the binding energy and the solvation energy of C60-6MP complexe using density functional theory (DFT).In order to explore whether doping atoms with different properties can change the adsorption performance of 6MP on C60, we replaced one carbon atom of C60 with three different atoms of Si, Al and Ti.The results showed that the binding energy of C59-X-6MP(X = Si, Al, Ti) complexes are higher than C60-6MP complexe, and the solvation energy are lower, which indicating that doping can improve the drug delivery characteristics of C60 to make it easier to release the drug. In addition, in different atom doped fullerenes, the doped transition metal Ti fullerene is more suitable as 6MP carrier. This study provides a theoretical basis for the design of 6MP anticancer drugs in the future.