A Stable Calcium Alumanyl Schwamm, Ryan J.; Coles, Martyn P.; Hill, Michael S. ...
Angewandte Chemie International Edition,
March 2, 2020, Letnik:
59, Številka:
10
Journal Article
Recenzirano
Odprti dostop
A seven‐membered N,N′‐heterocyclic potassium alumanyl nucleophile is introduced and utilised in the metathetical synthesis of Mg−Al and Ca−Al bonded derivatives. Both species have been characterised ...by experimental and theoretical means, allowing a rationalisation of the greater reactivity of the heavier group 2 species implied by an initial assay of their reactivity.
AlCan Wrap: The Reaction of a seven‐membered cyclic alumanyl anion with a β‐diketiminato calcium tetraphenylborate provides facile access to a stable, but highly reactive, calcium alumanyl.
A stable capillary liquid jet formed by an electric field is an important physical phenomenon for formation of controllable small droplets, power generation and chemical reactions, printing and ...patterning, and chemical-biological investigations. In electrohydrodynamics, the well-known Taylor cone-jet has a stability margin within a certain range of the liquid flow rate (Q) and the applied voltage (V). Here, we introduce a simple mechanism to greatly extend the Taylor cone-jet stability margin and produce a very high throughput. For an ethanol cone-jet emitting from a simple nozzle, the stability margin is obtained within 1 kV for low flow rates, decaying with flow rate up to 2 ml/h. By installing a hemispherical cap above the nozzle, we demonstrate that the stability margin could increase to 5 kV for low flow rates, decaying to zero for a maximum flow rate of 65 ml/h. The governing borders of stability margins are discussed and obtained for three other liquids: methanol, 1-propanol and 1-butanol. For a gravity-directed nozzle, the produced cone-jet is more stable against perturbations and the axis of the spray remains in the same direction through the whole stability margin, unlike the cone-jet of conventional simple nozzles.
K{Al(NONDipp)}2 (NONDipp=O(SiMe2NDipp)22−, Dipp=2,6‐iPr2C6H3) reacts with CS2 to afford the trithiocarbonate species K(OEt2)Al(NONDipp)(CS3) 1 or the ethenetetrathiolate complex, K{Al(NONDipp)(S2C)}2 ...32. The dimeric alumoxane K{Al(NONDipp)(O)}2 reacts with carbon monoxide to afford the oxygen analogue of 3, K{Al(NONDipp)(O2C)}2 42 containing the hitherto unknown ethenetetraolate ligand, C2O44−.
KAl(NONDipp) has been used to construct new C=C double bonds. The reaction with CS2 generates the ethenetetrathiolate C2S44− containing product through a reductive coupling strategy. To obtain similar carbon–oxygen products, the alumoxane K{Al(NONDipp)(O)}2 was reacted with CO, affording a hitherto unknown ethenetetraolate C2O44− ligand. DFT analysis indicates retention of a bimetallic species throughout the reaction with CO.
Ambiphilic Al−Cu Bonding Liu, Han‐Ying; Schwamm, Ryan J.; Hill, Michael S. ...
Angewandte Chemie (International ed.),
June 21, 2021, Letnik:
60, Številka:
26
Journal Article
Recenzirano
Odprti dostop
Copper‐alumanyl complexes, LCu‐Al(SiNDipp), where L=carbene=NHCiPr (N,N′‐diisopropyl‐4,5‐dimethyl‐2‐ylidene) and Me2CAAC (1‐(2,6‐diisopropylphenyl)‐3,3,5,5‐tetramethyl‐pyrrolidin‐2‐ylidene) and ...featuring unsupported Al−Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides and CO2 implies an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co‐ligand.
Cu(ts) both ways: Carbene‐supported copper‐alumanyl complexes, LCu‐Al(SiNDipp), display divergent reactivity with carbodiimides and CO2, implying an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co‐ligand.
One of the major challenges in targeted drug delivery to cancer cells is the practical use of high-precision drug carriers. Extensive theoretical research has been done in this field. Among these ...studies, the use of harmless nanoclusters has attracted the attention of many researchers. Among them, boron phosphide nanoclusters have also received more attention. In this regard, in this research, the adsorption, thermodynamic, and quantum chemical study of all the designed complexes of 5-Fluorouracil (5-FU) anticancer drug with the pristine and Sc- and Ti-doped boron phosphide nanocage (B
12
P
12
) in the presence of static electric field (SEF
z
+0.01,
SEF
z
+0.02
. SEF
z
+0.03
, SEF
z
+0.04
a.u.) have been carried out with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the ωB97XD/Lanl2DZ level of theory at 303.15 K. The adsorption energy (
E
ads
) and
∆H
values of all studied configurations are exothermic and with increasing the strength of the static electric field (SEF) from 0.01 to 0.04 a.u, decrease significantly from the original state. The ScB
11
P
12
is a good adsorbent of the 5-FU drug in the gas phase and is suitable for drug delivery in a water solvent. The molecular electrostatic potential (MEP) and
Q
NBO
results indicate that the surface of the 5-FU drug in the 5-FU&nanocage complex is suitable for attacking the nucleophilic compounds and it will mostly attack the sites of the cell that has a negative charge and is nucleophilic. Further, analysis of frontier molecular orbital, reduced density gradient, TD-DFT, electron localized function (ELF), and atom in the molecule (AIM) suggested that the Sc- and Ti-doped B
12
P
12
and the presence of static electric field are efficient candidates for 5-FU drug delivery and sensitive sensor.
The problem of analytical solutions of the 3-dimensional Dirac equation is usually studied via techniques such as The Nikiforov–Uvarov (NU) method. Here, we see that one of the most attractive ...potentials can be brought into a well-known form of Schrödinger-like problem possessing known solutions via the methodology of supersymmetry (SUSY). Next, using the idea of shape invariance, we calculate exact solutions of Dirac equation for quadratic scalar and vector potentials in the presence of a tensor potential that depends on the radial component either linearly or inversely. The tensor potential itself, besides its applications, removes degeneracy, too.
In this paper, the techniques for the synthesis of CaFe2O4 nanoparticles using the auto-combustion and co-precipitation methods are discussed. The effects of both methods on the microstructure and ...magnetic properties of the CaFe2O4 nanoparticles were compared. The CaFe2O4 powder was obtained after drying the synthesized sample via co-precipitation overnight in an oven at 80°C. For auto-combustion method, the sol that was initially formed was gradually converted into a gel, which was then combusted at 250°C. Finally, the CaFe2O4 nanoparticles were calcined at 550°C. The different synthesis methods produced nanoparticles with different physical and magnetic properties in order to find an optimum size to be utilized for drug delivery applications. The results of the X-ray diffraction showed that both processes produced nanocrystals with an orthorhombic crystalline structure. It was noted from the measurements made with a transmission electron microscope (TEM) that the synthesis using the co-precipitation method produced nanoparticles with a size of about 10–20nm, which was comparable with the size that was obtained when the auto-combustion method was used. The magnetic properties were investigated using a vibrating sample magnetometer (VSM), where the magnetic saturation (Ms) of CaFe2O4 for the sample synthesized using the co-precipitation method was 47.279emu/g, which was higher than the magnetic saturation (Ms) of 31.10emu/g obtained when the auto-combustion method was used. The hysteresis loops (Hc) for the samples were 17.380G and 6.1672G, respectively. Additionally, the elaborate properties mentioned above, such as the size and superparamagnetic properties of the synthesized CaFe2O4 nanoparticle size, were the characteristics required for drug delivery because the targeted therapy required nanoparticles with good magnetic properties, a suitable size, and which were non-toxic in order to have a potential application in targeted drug delivery systems.
Reaction of Ru(PPh3)3HCl with LiCH2TMS, MgMe2, and ZnMe2 proceeds with chloride abstraction and alkane elimination to form the bis-cyclometalated derivatives Ru(PPh3)(C6H4PPh2)2HM′ where M′ = ...Li(THF)2+ (1), MgMe(THF)2+ (3), and ZnMe+ (4), respectively. In the presence of 12-crown-4, the reaction with LiCH2TMS yields Ru(PPh3)(C6H4PPh2)2HLi(12-crown-4)2 (2). These four complexes demonstrate increasing interaction between M′ and the hydride ligand in the Ru(PPh3)(C6H4PPh2)2H− anion following the trend 2 (no interaction) < 1 < 3 < 4 both in the solid-state and solution. Zn species 4 is present as three isomers in solution including square-pyramidal Ru(PPh3)2(C6H4PPh2)(ZnMe) (5), that is formed via C–H reductive elimination and features unsaturated Ru and Zn centers and an axial Z-type ZnMe+ ligand. A ZnMe+ adduct of 5, Ru(PPh3)2(C6H4PPh2)(ZnMe)2BArF 4 (6) can be trapped and structurally characterized. 4 reacts with H2 at −40 °C to form Ru(PPh3)3(H)3(ZnMe), 8-Zn, and contrasts the analogous reactions of 1, 2, and 3 that all require heating to 60 °C. This marked difference in reactivity reflects the ability of Zn to promote a rate-limiting C–H reductive elimination step, and calculations attribute this to a significant stabilization of 5 via Ru → Zn donation. 4 therefore acts as a latent source of 5 and this operational “dual unsaturation” highlights the ability of Zn to promote reductive elimination in these heterobimetallic systems. Calculations also highlight the ability of the heterobimetallic systems to stabilize developing protic character of the transferring hydrogen in the rate-limiting C–H reductive elimination transition states.
•Although, binders are responsible for increasing of toughness in the cermets, fracture toughness can decrease due to stress concentration in the metal phase.•The excellent wear resistance can be ...derived from hardness of ceramic particles and binder toughness.•Mo can improve wettability between the binder and the ceramic phase.•Dissolution of Ti(CN) particles terminated due to (Ti,Mo)(CN) grey rim formation on cores.
In the recent years, cermets have acquired considerable development, and attention is now being given at the production of TiC-based cermets because of their unique properties. Despite all of the superior specifications, however, TiC cermets showed insufficient toughness. Thus, the current study aims to review the effective factors that can decrease the brittleness in the aforementioned cermets through various binders. Successful findings have been achieved in this respect by using Ni, Mo and Ni-Mo as binder in the TiC-based cermets. These cermets exhibit promising features which, hopefully, can be a sufficient replacement for common cermets (WC-Co). Current critical issues are also discussed in this study, such as the effects of grain size and chemical composition of binders including toughness, hardness, and wear resistance. This study also highlights the major drawbacks in producing TiC-based cermets, and tries to introduce possible suggestions for overcoming the problems considered in this area.
Seven‐Membered Cyclic Potassium Diamidoalumanyls Schwamm, Ryan J.; Hill, Michael S.; Liu, Han‐Ying ...
Chemistry : a European journal,
October 25, 2021, Letnik:
27, Številka:
60
Journal Article
Recenzirano
Odprti dostop
The seven‐membered cyclic potassium alumanyl species, {SiNMes}AlK2 {SiNMes}={CH2SiMe2N(Mes)}2; Mes=2,4,6‐Me3C6H2, which adopts a dimeric structure supported by flanking K‐aryl interactions, has been ...isolated either by direct reduction of the iodide precursor, {SiNMes}AlI, or in a stepwise manner via the intermediate dialumane, {SiNMes}Al2. Although the intermediate dialumane has not been observed by reduction of a Dipp‐substituted analogue (Dipp=2,6‐i‐Pr2C6H3), partial oxidation of the potassium alumanyl species, {SiNDipp}AlK2, where {SiNDipp}={CH2SiMe2N(Dipp)}2, provided the extremely encumbered dialumane {SiNDipp}Al2. {SiNDipp}AlK2 reacts with toluene by reductive activation of a methyl C(sp3)‐H bond to provide the benzyl hydridoaluminate, {SiNDipp}AlH(CH2Ph)K, and as a nucleophile with BPh3 and RN=C=NR (R=i‐Pr, Cy) to yield the respective Al‐B‐ and Al‐C‐bonded potassium aluminaborate and alumina‐amidinate products. The dimeric structure of {SiNDipp}AlK2 can be disrupted by partial or complete sequestration of potassium. Equimolar reactions with 18‐crown‐6 result in the corresponding monomeric potassium alumanyl, {SiNDipp}Al−K(18‐cr‐6), which provides a rare example of a direct Al−K contact. In contrast, complete encapsulation of the potassium cation of {SiNDipp}AlK2, either by an excess of 18‐cr‐6 or 2,2,2‐cryptand, allows the respective isolation of bright orange charge‐separated species comprising the ‘free’ {SiNDipp}Al− alumanyl anion. Density functional theory (DFT) calculations performed on this moiety indicate HOMO‐LUMO energy gaps in the of order 200–250 kJ mol−1.
Seven‐membered cyclic potassium diamidoalumanyls react with toluene by reductive activation of a methyl C(sp3)−H bond and as a nucleophile with BPh3 and RN=C=NR (R=i‐Pr, Cy) to yield the respective Al‐B‐ and Al‐C‐bonded potassium aluminaborate and alumina‐amidinate products. The dimeric structure of {SiNDipp}AlK2 can be disrupted by partial or complete sequestration of potassium with 18‐cr‐6 or 2,2,2‐cryptand to provide either Al−K bonded or charge‐separated species comprising the ‘free’ alumanyl anion.
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