Platinum Atoms Research Articles

Synthesis, X-ray Structure, and Catalytic Activity in the Hydrosilylation Process of Platinum Complexes Bearing Buchwald Ligands

The controlled reaction between [Pt2(DVTMS)3], where DVTMS represents 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and dialkylbiaryl phosphines (Buchwald ligands) 2-(di-tert-butylphosphino)biphenyl (JohnPhos, 1), 2-(dicyclohexylphosphino)biphenyl (CyJohnPhos, 2), 2-di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl (tBuXPhos, 3), 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (XPhos, 4), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (SPhos, 5), 2-dicyclohexylphosphino-2′-(N,N-dimethylamino)biphenyl (DavePhos, 6), and 2-dicyclohexylphosphino-2′,4′,6′-trimethoxybiphenyl (MeOSPhos, 7) generates an efficient platinum catalyst of type [Pt(DVTMS)(L)] (1a–7a), where L represents the Buchwald ligand, applied for hydrosilylation of phenylacetylene by diphenylsilane. The X-ray crystal structure analysis of the obtained Pt catalysts showed the presence of specific Pt-aryl interactions with the phenyl group of the dialkylbiarylphosphine ligand in complex 1a, while the same effect was not observed for the related 2′,4′,6′-triisopropyl substituted aromatic ring in 3a. The evaluation of the steric parameters from X-ray diffraction analysis (XRD) showed the increase of the steric hindrances around the platinum atom improves the selectivity and the yield of the β(E)-product.

Cisplatin reacts with the RING finger domain of RNF11 and interferes with the protein functions.

Protein reactions play important roles in the mechanism of action of cisplatin. In this work, we found that cisplatin is highly reactive to the RING finger domain of RNF11, a key protein involved in tumorigenesis and metastasis. The results show that cisplatin binds to RNF11 at the zinc coordination site and leads to zinc-ejection from the protein. The formation of S-Pt(II) coordination and Zn(II) ions release have been confirmed by UV-vis spectrometry using zinc dye and thiol agent, showing reducing the contents of thiol groups while forming S-Pt bonds and releasing zinc ions. ESI-MS measurement indicates that each RNF11 can bind up to three platinum atoms. Kinetical analysis shows a reasonable platination rate of RNF11 with t1/2 ∼ 3 h. CD, NMR and gel electrophoresis measurements indicate that the cisplatin reaction causes protein unfolding and oligomerization of RNF11. Pull-down assays confirms that the platination of RNF11 interferes with the protein interaction of RNF11 with UBE2N, a key step of the functionalization of RNF11. Furthermore, Cu(I) was found to promote the platination of RNF11, which could lead to increased protein reactivity to cisplatin in tumor cells with high copper level. These results indicate that the platination-induced zinc-release of RNF11 disrupts the protein structure and interferes with its functions.

First principles calculations of electronic and optical properties of InSe nanosheets doped with noble metal atoms

Monolayer Indium Selenide (ML-InSe) is studied for 4x4 supercell structure through ab initio calculations. The electronic and optical properties of ML-InSe for both pristine and substitutional doped ML-InSe with Palladium (Pd), Platinum (Pt), Silver (Ag), and Gold (Au) atoms have been calculated. With substitutional doping, ML-InSe has been observed to have a spin-dependent electronic structure. The flat energy bands near the Fermi level are observed in ML-InSe with doping elements placed in In site. The flat bands of d orbitals of some noble metal atoms are formed by the projected density of states (PDOS). The PDOS calculations show that the s-orbital of In and p-orbital of Se form the conduction band edge. The energetically favorable position of doping atoms is found to be the PtIn substitution atom according to formation energy calculations. For each studied structure, the bond length of the first neighbor of doping atoms in doped ML-InSe, static dielectric constant (ε0), refractive index, and energy band gap have been calculated. In the structure ML-InSe with AuSe, ε0 reaches ∼ 8.15. Another important result is that substitutional doping induces some peaks in the lower energy region of the imaginary part of the dielectric function. These peaks mainly refer to the absorption in related regions and may be important for the optoelectronic properties of ML-InSe.

Isolated Pt Species Anchored by Hierarchical-like Heteroatomic Fe-Silicalite-1 Catalyze Propane Dehydrogenation near the Thermodynamic Limit

The atomic dispersion of precious metals accompanied by maximum atom utilization can provide specific chemical properties compared to nanoparticles and clusters that have attracted widespread interest. The selection of a suitable carrier to stabilize platinum atoms while maintaining high stability and propylene selectivity is of great challenge for propane dehydrogenation reactions operating at extremely high temperatures. Here, we report a conceptually designed catalyst comprising isolated Pt atoms stably bonded through skeleton O in a hierarchical-like heteroatomic ferrosilicate zeolite (H-Fe-S-1–3; denoted as “Fe-3”), capable of achieving high propane conversions at different temperatures and atmospheres close to the thermodynamic limit. No significant deactivation was observed for 3 days in a pure propane atmosphere at 580 °C, outperforming most of the cutting-edge Pt-based catalysts. The moderate acidity of Fe-3 and anchoring of hydroxyl species other than silanol nests were responsible for maintaining a suitable C–H break rather than an excessive C–C cleavage capacity and a high degree of Pt dispersion, respectively. X-ray absorption spectra and atomically resolved high-angle annular dark-field electron microscopy demonstrated major atomic dispersion of Pt species, along with complementary density functional theory calculations to determine the structure of ≡Si–O–Pt–O–Fe≡ corresponding to the T4 location as the key active site. Pt anchoring by sites other than the T4 site with analogous energies, such as T6, could be accountable for the observation that “cluster-like Pt species” are essentially composed of isolated Pt atoms not interacting with each other.

Preferential deposition of gold and platinum atom on palladium nanocube as catalysts for oxidizing glucose in the phosphate-buffered solution

Preferential deposition of gold and platinum atom on palladium nanocube as catalysts for oxidizing glucose in the phosphate-buffered solution

Synergistic Interactions of Neighboring Platinum and Iron Atoms Enhance Reverse Water-Gas Shift Reaction Performance.

The limitations of conventional strategies in finely controlling the composition and structure demand new promotional effects for upgrading the reverse water-gas shift (RWGS) catalysts for enhanced fuel production. We report the design and synthesis of a hetero-dual-site catalyst for boosting RWGS performance by controllably loading Fe atoms at the neighboring Pt atom on the surface of commercial CeO2. The Fe-Pt/CeO2 exhibits a remarkably high catalytic performance (TOFPt: 43,519 h-1) for CO2 to CO conversion with ∼100% CO selectivity at a relatively low temperature of 350 °C. Furthermore, the catalyst retains over 80% activity after 200 h of continuous operation. The experimental and computational investigations reveal a "two-way synergistic effect", where Fe atoms can not only serve as promotors to alter the charge density of Pt atoms but also be activated by the excess active hydrogen species generated by Pt atoms, enhancing catalytic activity and stability.

Will the Interactions of Some Platinum (II)-Based Drugs with B-Vitamins Reduce Their Therapeutic Effect in Cancer Patients? Comparison of Chemotherapeutic Agents such as Cisplatin, Carboplatin and Oxaliplatin-A Review.

Pt (II) derivatives show anti-cancer activity by interacting with nucleobases of DNA, thus causing some spontaneous and non-spontaneous reactions. As a result, mono- and diaqua products are formed which further undergo complexation with guanine or adenine. Consequently, many processes are triggered, which lead to the death of the cancer cell. The theoretical and experimental studies confirm that such types of interactions can also occur with other chemical compounds. The vitamins from B group have a similar structure to the nucleobases of DNA and have aromatic rings with single-pair orbitals. Theoretical and experimental studies were performed to describe the interactions of B vitamins with Pt (II) derivatives such as cisplatin, oxaliplatin and carboplatin. The obtained results were compared with the values for guanine. Two levels of simulations were implemented at the theoretical level, namely, B3LYP/6-31G(d,p) with LANL2DZ bases set for platinum atoms and MN15/def2-TZVP. The polarizable continuum model (IEF-PCM preparation) and water as a solvent were used. UV-Vis spectroscopy was used to describe the drug-nucleobase and drug-B vitamin interactions. Values of the free energy (ΔGr) show spontaneous reactions with mono- and diaqua derivatives of cisplatin and oxaliplatin; however, interactions with diaqua derivatives are more preferable. The strength of these interactions was also compared. Carboplatin products have the weakest interaction with the studied structures. The presence of non-covalent interactions was demonstrated in the tested complexes. A good agreement between theory and experiment was also demonstrated.

Single Platinum Atom Catalysts with HighDensity.

As a new frontier, the rapid development of single-atom catalysts (SACs) in heterogeneous catalysis has attracted extensive attention. However, a fundamental understanding of the dynamic formation process of active metal atom sites is lacking. The rational design of high-performance SACs now becomes possible byexplicitly addressing the conundrum of constructing high-density SACs and elucidating the evolution of SACs during the synthesis.

Single Platinum Atom Catalysts with High Density

AbstractAs a new frontier, the rapid development of single‐atom catalysts (SACs) in heterogeneous catalysis has attracted extensive attention. However, a fundamental understanding of the dynamic formation process of active metal atom sites is lacking. The rational design of high‐performance SACs now becomes possible by explicitly addressing the conundrum of constructing high‐density SACs and elucidating the evolution of SACs during the synthesis.

Formation of pyramidal structures through mixing gold and platinum atoms: the AuxPty2+ clusters with x + y = 10.

The geometric and electronic structures of a small series of mixed gold and platinum AuxPty2+ clusters, with x + y = 10, were investigated using quantum chemical methods. A consistent tetrahedral pyramid structure emerges, displaying two patterns of structural growth by a notable critical point at y = 5. This affects the clusters' electron population, chemical bonding, and stability. For the Pt-doped Au clusters with y values from 2 to 5, the bonds enable Pt atoms to assemble into symmetric line, triangle, quadrangle, and tetragonal pyramidal Pty blocks, respectively. For the Au-doped Pt clusters, with larger values of y > 5, the structures are more relaxed and the d electrons of Pt atoms become delocalized over more centers, leading to lower symmetry structures. A certain aromaticity arising from delocalization of d electrons over the multi-center framework in the doped Pt clusters contributes to their stability, with Pt102+ at y = 10 exhibiting the highest stability. While the ground electronic state of the neutral platinum atom [Xe]. 4f145d96s1 leads to a triplet state (3D3), the total magnetic moments of AuxPty2+ are large increasing steadily from 0 to 10 μB and primarily located on Pt atoms, corresponding to the increase of the number of Pt atoms from 0 to 10 and significantly enhancing the magnetic moments. An admixture of both Au and Pt atoms thus emerges as an elegant way of keeping a small pyramidal structure but bringing in a high and controllable magnetic moment.

Highly dispersed Pt with CoFeP hollow nanocages for efficient oxygen evolution reaction

The strong binding energy of Pt with oxygen intermediates results in its low OER efficiency at the anode. Herein, Pt-doped CoFeP (Pt-CoFeP) material has been synthesized using CoFe-PBA as precursor through facile etching and phosphating processes. Interestingly, Pt-CoFeP with hollow cage framework exhibits large surface area after etching, which plays a domain-limiting role for the high dispersion of platinum atoms and facilitates the oxygen evolution reaction (OER). The target sample Pt-CoFeP only needs low overpotentials of 311.7 and 343.1 mV to deliver the current density of 10 and 50 mA cm-2, which is superior to commercial RuO2. The excellent activity can be attributed to large specific surface area in hollow framework and highly dispersed platinum atoms. And its great durability is evaluated through chronoamperometry measurement for 12 hours. This work provides a potential method to design electrocatalysts with complex structure loaded with highly dispersed Pt particles derived from Prussian blue analogues (PBAs) for water splitting.

SYNTHESIS AND STRUCTURE OF PLATINUM (II) COMPLEXES WITH DECOMPOSITION PRODUCT OF DITHIODIETHYLAMINE βMERCAPTOETHYLAMINE

The interaction of dithiodiethylamine (cystamine) (L1 ) with Pt(II) in aqueous medium was studied and it showed that in aqueous solutions in an acidic medium, the disulfide bond L1 was cleaved, followed by coordination of platinum to form β-mercaptoethylamine (mercamine, LH). Depending upon the reaction conditions, binuclear complexes of composition µ(S)[Рt2(LН)2С14](I), µ(Cl)[Рt2(LН)2С14](II) with bridging chlorine or sulfur atoms were formed. At 70°С, a compound with a bridged position of sulfur atoms (complex I), and at lower temperatures (30-500 ) with a bridged position of chlorine atoms (complex II) were formed. X-ray structural analysis of the complex [Рt2(LН)2С14] (I) was carried out. Crystals I are rhombic, with 20°Са = 17.282(1), b = 9.986(1), с = 8.0188(9) Å;R = 0.029. Molecule I is a binuclear complex in which platinum atoms are linked by a pair of bridging thiolate ligands (-SСН2-СН2-МН3 + ). The Pt2S2 metallocycleis are bent along the sulfur-sulfur line, so that the dihedral angle between the coordination planes of platinum atoms is equal to 138°. The S–S distance, equal to 2.909(1) Å, is noticeably shorter than the doubled van der Waals radius of the sulfur atom (3.60 Å). The structure of the complexes was also confirmed by IR spectroscopy data.

Single platinum atoms anchored on N-doped carbon materials composed of bipyridine as efficient hydrogen evolution electrocatalysts

Potassium tetrachloroplatinate among three platinum salts shows the most favorable binding energy to a N-doped carbon material composed of bipyridine, and enables the anchoring of Pt single atoms as efficient hydrogen evolution electrocatalysts.

A DFT studies on absorbing and sensing possibilities of glucose on graphene surface doped with Ag, Au, Cu, Ni & Pt atoms

The adsorption of glucose is theoretically examined using the Density Functional Theory method (DFT) over pure graphene and graphene surface doped with transition metal atoms (silver, gold, copper, nickel, and platinum). The graphene sheets are altered by substitutional doping of silver, gold, copper, nickel, and platinum atoms remarks in altering the electronic properties and actively reassuring glucose absorption. The outcomes revealed that metal atoms doped with graphene sheets improve the reactivity. Our study found that the interaction of glucose with pure graphene is weak when compared to metal-doped graphene flakes. Our studies concluded that due to strong adsorption energies, high bandgap variation, and excellent work function values of metal-doped graphene sheets make them beneficial for glucose sensing devices. The sensitivity and conductivity variations are high for the metal doped graphene sheets except nickel, however the recovery time value is high, suggesting that these sheets can be used as a disposable sensor.

Effects of Single Platinum Atom Doping on Stability and Nonlinear Optical Properties of Ag29 Nanoclusters

The properties of atomically precise noble metal nanoclusters can be modified by the addition of other metals, which may offer augmented characteristics, making them more suitable for real-life applications. In this work, we report the effects of single platinum atom doping of a class of atomically precise silver nanoclusters protected by dithiolated ligands on their optical properties both in linear and nonlinear optical (NLO) regimes and on their stability over time. Pt doping of Ag29 preserves their NLO properties (in particular two-photon excited photoluminescence).

Localizing electrons on atomic platinum by metal phosphides for accelerating electrocatalytic hydrogen evolution

The development of the electrical metal-support interaction for boosting alkaline hydrogen evolution reaction (HER) is essential for the high catalytic performance of Pt-based single atom catalysts (SACs). Herein, we design the Pt single atoms immobilized Ni2P nanosheet arrays on the nickel foam (PtSA-Ni2P@NF) to construct a 3D hierarchical nanostructure as an alkaline HER catalyst. It is found that the 3D continuous NF and the conductive Ni2P array support provide an efficient electron transport path for Pt single atoms, which can significantly reduce the charge transfer impedance and increase the electrochemical active sites to accelerate HER process in the alkaline electrolyte. Density functional theory calculations and structural analytical data confirm that PtSA-Ni2P@NF displays the suitable interaction between Pt single atoms and Ni2P support with the formation of Pt-P bonds at the interface, contributing to the high electric field intensity to provide more localized free electrons for accelerating H2O dissociation process to enhance the favorable H* adsorption and H2 release. The energy required to remove adsorbed H from the reaction site for our PtSA-Ni2P@NF is found to be the lowest for PtSA-Ni2P@NF (ΔE = −0.05 eV). Electrocatalytic experiments exhibit that PtSA-Ni2P@NF displays the outstanding HER activity with a low overpotential of 26 mV at a current density of 10 mA cm−2. The mass activity (19.2 mgPt−1) of PtSA-Ni2P@NF is 43.6 times higher than that of the commercial benchmark catalyst (0.4 A mgPt−1, 20 % Pt/C).

Theoretical interpretations of photoelectron spectra of platinum atom, its cation and anion

Results of theoretical research on the ground and excited states of the platinum atom, its Pt− anion, and Pt+ cation are presented. Calculations were carried out using the four-component multi-configuration Dirac-Hartree-Fock method with the spin-free relativistic eight-order Douglas-Kroll-Hess method, and the infinite order two-component method at high correlated level. The spin-orbit (SO) coupling is introduced via the restricted active space state interaction method with the use of the atomic mean field SO integrals. The results are interpreted in comparison with the experimental data. The theoretical analysis suggests different assignments and interpretations of some atomic and ionic states, and existence of three anionic bound states. The obtained electron affinity to Pt−5d96s22D5/2 ground state is 2.104 eV (experimental value is 2.125 eV) which can be considered as very accurate result. The photodetachment Pt−1 to Pt0 spectra is provided. A comparative analysis of the accuracy of two-component methods is also presented.

Bimetallic NiPt nanoparticles-enhanced catalyst supported on alginate-based biohydrogels for sustainable hydrogen production

Alginate hydrogel beads were loaded with bimetallic NiPt nanoparticles by in situ reduction of the respective polymer matrix containing precursor metallic ions using a NaBH4 aqueous solution. The alginate hydrogel beads loaded with NiPt nanoparticles were characterized by TEM, AAS, FT-IR, TGA, XPS, and oscillatory rheometry. The prepared hybrid hydrogels were proven to be effective as catalytic materials for the hydrolysis of ammonia borane (AB) for quantitative hydrogen generation using catalytic loadings of 0.1 mol%. In addition, the reaction mechanism of the hydrolytic reaction using NiPt loaded alginate hydrogel beads was determined by Langmuir-Hinshelwood model. The experimental results showed that the reaction mechanism consisted of an initial fast adsorption of reactants at the surface of the nanoparticles, followed by a rate-limiting surface reaction. The NiPt nanoalloys exhibited an enhanced behavior for hydrogen generation with a maximum TOF of 84.1 min−1, almost 71 % higher compared to monometallic platinum atoms, and likely related to a synergistic interaction between both metals. Finally, the hydrogel matrix enabled the material to be easily recovered from the reaction medium and reused in further catalytic cycles without desorption of active nanoparticles from the material.

Porphyrin Hetero-Trimer Involving a Hydrophilic and a Hydrophobic Structure with Application in the Fluorescent Detection of Toluidine Blue

The combination of a metallated porphyrin, Pt(II)-5,10,15,20-tetrakis-(4-allyloxyphenyl)-porphyrin (Pt-allyloxyPP), and a water-soluble porphyrin, 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TSPP), leads to the formation of a porphyrin hetero-trimer. The hetero-trimer, consisting of two TSPP molecules linked via oxygen atoms axially to the platinum atom in the Pt-allyloxyPP molecule, was characterized by UV–Vis, FT-IR, fluorescence, and 1H-NMR spectroscopy, and the proposed structure was confirmed. The new porphyrin hetero-trimer offers both the advantage of enhanced fluorescence and the presence of multiple sites for the detection of toluidine blue, due to its high affinity for acidic binding sites. This work brings attention to the purposely designed fluorescent sensor for toluidine blue, in the biologically relevant concentration domain of 1.9 × 10−6–6.39 × 10−5 M, with a very good accuracy.

Pinpointing the axial ligand effect on platinum single-atom-catalyst towards efficient alkaline hydrogen evolution reaction

Developing active single-atom-catalyst (SAC) for alkaline hydrogen evolution reaction (HER) is a promising solution to lower the green hydrogen cost. However, the correlations are not clear between the chemical environments around the active-sites and their desired catalytic activity. Here we study a group of SACs prepared by anchoring platinum atoms on NiFe-layered-double-hydroxide. While maintaining the homogeneity of the Pt-SACs, various axial ligands (−F, −Cl, −Br, −I, −OH) are employed via a facile irradiation-impregnation procedure, enabling us to discover definite chemical-environments/performance correlations. Owing to its high first-electron-affinity, chloride chelated Pt-SAC exhibits optimized bindings with hydrogen and hydroxide, which favor the sluggish water dissociation and further promote the alkaline HER. Specifically, it shows high mass-activity of 30.6 A mgPt−1 and turnover frequency of 30.3 H2 s−1 at 100 mV overpotential, which are significantly higher than those of the state-of-the-art Pt-SACs and commercial Pt/C catalyst. Moreover, high energy efficiency of 80% is obtained for the alkaline water electrolyser assembled using the above catalyst under practical-relevant conditions.