Cezar Comanescu

• PhD
• PostDoc Position at University of Notre Dame

A methodology for the quantitative estimation of the drug loading of iron oxide-based magnetic nanoparticles by corroborating magnetometry and Mössbauer spectroscopy investigations is reported. The proposed methodology is exemplified in the case of two series of nanoparticles, namely Fe3O4 nanoparticles covered with citric acid molecules and furthe...

Lithium-ion batteries (LIBs) are fundamental to modern technology, powering everything from portable electronics to electric vehicles and large-scale energy storage systems. As their use expands across various industries, ensuring the reliability and safety of these batteries becomes paramount. This review explores the multifaceted aspects of LIB r...

Antidepressant drugs play a crucial role in the treatment of mental health disorders, but their efficacy and safety can be compromised by drug degradation. Recent reports point to several drugs found in concentrations ranging from the limit of detection (LOD) to hundreds of ng/L in wastewater plants around the globe; hence, antidepressants can be c...

In recent years, significant progress has been made in the surface functionalization of magnetic nanoparticles (MNPs), revolutionizing their utility in multimodal imaging, drug delivery, and catalysis. This progression, spanning over the last decade, has unfolded in discernible phases, each marked by distinct advancements and paradigm shifts. In th...

Microemulsions are nanocolloidal systems composed of water, an oil, and a surfactant, sometimes with an additional co-surfactant, which have found a wide range of practical applications, including the extractive removal of contaminants from polluted water. In this study, microemulsion systems, including a nonionic surfactant (Brij 30), water, and e...

Calcium borohydride (Ca(BH4)2) is a complex hydride that has been less investigated compared to its lighter counterpart, magnesium borohydride. While offering slightly lower hydrogen storage capacity (11.5 wt% theoretical maximum, 9.6 wt% under actual dehydrogenation conditions), there are many improvement avenues for maximizing the reversible hydr...

Energy production, distribution, and storage remain paramount to a variety of applications that reflect on our daily lives, from renewable energy systems, to electric vehicles and consumer electronics. Hydrogen is the sole element promising high energy, emission-free, and sustainable energy, and metal hydrides in particular have been investigated a...

In this study, we report on the synthesis of L-Cysteine (L-Cys)-coated magnetic iron oxide nanoparticles (NPs) loaded with doxorubicin (Dox). The Fe3O4-L-Cys-Dox NPs were extensively characterized for their compositional and morpho-structural features using EDS, SAED, XRD, FTIR and TEM. XPS, Mӧssbauer spectroscopy and SQUID measurements were also p...

Featuring a high hydrogen storage content of up to 20 wt%, complex metal borohydrides remain promising solid state hydrogen storage materials, with the real prospect of reversible behavior for a zero–emission economy. However, the thermodynamic barriers and sluggish kinetics are still barriers to overcome. In this context, nanoconfinement has provi...

Hydrides have emerged as strong candidates for energy storage applications and their study has attracted wide interest in both the academic and industry sectors. With clear advantages due to the solid-state storage of hydrogen, hydrides and in particular complex hydrides have the ability to tackle environmental pollution by offering the alternative...

Magnetic nanoparticles (MNPs) have evolved tremendously during recent years, in part due to the rapid expansion of nanotechnology and to their active magnetic core with a high surface-to-volume ratio, while their surface functionalization opened the door to a plethora of drug, gene and bioactive molecule immobilization. Taming the high reactivity o...

Hydrogen is the ultimate vector for a carbon-free, sustainable green-energy. While being the most promising candidate to serve this purpose, hydrogen inherits a series of characteristics making it particularly difficult to handle, store, transport and use in a safe manner. The researchers’ attention has thus shifted to storing hydrogen in its more...

Novel (1-x) SrFe12O19 – x BNT-BT0.08 (x = 0; 0.5; 0.8; 1) nanocomposites were explored in this study. The samples were produced by sol-gel method and compacted by conventional sintering. The composition, morphology, local structure, dielectric and magnetic properties were investigated by X-ray diffraction, Transmission Electron Microscopy, Impedanc...

Despite being the lightest element in the periodic table, hydrogen poses many risks regarding its production, storage, and transport, but it is also the one element promising pollution-free energy for the planet, energy reliability, and sustainability. Development of such novel materials conveying a hydrogen source face stringent scrutiny from both...

Exchange coupling in a SrFe12O19 - Fe3O4 nanocomposite magnet was explored in this study. The composition, microstructure, local structure and magnetic properties were investigated by XRD, SEM, Mossbauer spectroscopy, and SQUID magnetometry. The magnetoplumbite SrFe12O19 and spinel Fe3O4 structures were verified by X-ray diffraction. The morphology...

The dielectric and electric properties of a core-shell SrFe12O19 – BNT-BT nanocomposite were explored in this study. The desired composition and the existence of the magnetoplumbite SrFe12O19 and perovskite BNT-BT structures were verified by X-ray diffraction. The dielectric constant values approached the case of BNT-BT due to the small amount of h...

Fe oxide magnetic nanoparticles (MNPs) in general and cobalt ferrite nanoparticles in particular have immense potential for applications in catalysis, medicine, information and energy storage, etc. MNPs feature interesting physical and chemical properties, different to those of corresponding bulk materials. The magnetic anisotropy constant of almos...

Issues related to the optimization of heat transfer mechanisms dominated by superparamagnetic relaxation are considered in the case of AC (alternating current) magnetic field hyperthermia procedures. The key role in the conversion of electromagnetic energy to the thermal one via the superparamagnetic relaxation mechanism is played by the magnetic a...

A facile and cheap surfactant-assisted hydrothermal method was used to prepare mesoporous cobalt ferrite nanosystems with BET surface area up to 151 m2/g. These mesostructures with high BET surface areas and pore sizes are made from assemblies of nanoparticles (NPs) with average sizes between 7.8 and 9.6 nm depending on the initial pH conditions. T...

o‐Alkenyl N‐triflylanilides underwent rhodium(III)‐catalyzed oxidative annulations with alkynes to produce different types of naphthylamides in a process which involves the cleavage of two C−H bonds. Remarkably, besides formal dehydrogenative (4C+2C) cycloadducts, the reaction also produces variable amounts of isomeric naphthylamides, whose formati...

o‐Alkenyl‐N‐triflylanilides undergo Rh(III)‐catalyzed oxidative annulations with alkynes to produce different types of naphthylamides, in a process which involves the cleavage of two C‐H bonds. Remarkably, in addition to formal dehydrogenative (4C+2C) cycloadducts, the reaction also produces variable amounts of isomeric naphthylamides whose formati...

The reactivity of a nucleophilic palladium carbene, [{PC(sp²)P}HPd(PMe3)] (1, [PC(sp²)P] = bis[2-(di-iso-propylphosphino)phenyl]methylene), towards 2,6-dimesitylphenyldiazomethane ((dmp)CHN2) and 2,6-dimesitylphenylazide ((dmp)N3) was explored. When treated with (dmp)CHN2, the carbene complex was fully consumed to generate a 3-coordinate Pd(0) comp...

A series of palladium pincer complexes supported by (iPr2P-C6H4)2CH2 (PC(sp3)H2P = bis(2- (diisopropylphosphanyl)phenyl)methane) was isolated and characterized. Different modes of C−H activation were observed for [{PC(sp3)H2P}PdX2] (X = Cl, OTf, Me, OAc). The thermal treatment of [{PC(sp3)H2P}PdX2] (X = Cl, OTf) induced a backbone C−H bond activati...

EH bond cleavage by [(PC(sp²)P)Pd(PMe3)] (1, PC(sp²)P = ⁱ Pr2PC6H4 CC6H4 P ⁱ Pr2) of alcohols led to a series of new square-planar tridentate palladium alkoxides, [(PC(sp³)HP)Pd(O ⁱ Pr)] (3), [(PC(sp³)HP)Pd(O t Bu)] (4), and [(PC(sp³)HP)Pd(OPh)] (5, PC(sp³)HP = bis[2-(di-iso-propylphosphino)phenyl]methyl). The analogous reaction with amines led to...

A series of chalcogen analogues encompassing a ketone and chalcogenoketones [{PC(=E)P}Pd(PMe3)] (E = O, S, Se, Te, [PC(sp3)HP] = bis[2-(di-iso-propylphosphino)-phenyl]methyl, iPr2P-C6H4-CH-C6H4-PiPr2) was generated from a nucleophilic palladium carbene compound, [{PC(sp2)P}Pd(PMe3)]. The thioketone, selenoketone, and telluroketone were all synthesi...

2-Alkenyltriflylanilides react with allenes upon treatment with catalytic amounts of Pd(OAc)2 and Cu(II) to give highly valuable 2,3-dihydro-1H-benzo[b]azepines, in good yields, and with very high regio- and diastereoselectivities. Density functional theory (DFT) calculations suggest that the C–H activation of the alkenylanilide involves a classica...

Amorphous hematite synthesized by a simple and fast microwave route was used to obtain Fe16N2 fine particles by reducing in 5% H2/Ar gas flow, followed by long time nitridation in ammonia gas flow at temperatures below 200⁰C. Depending on nitridation temperature, various amount of metallic iron was present along with α’’-Fe16N2 main phase. A small...

The reactivity of two nucleophilic palladium carbenes, [PC(sp2)P]Pd(PMe3) and [PC(sp2)P]Pd(PPh3), [PC(sp2)P] = bis[2-(di-iso-propylphosphino)phenyl]methylene, toward the E-H bond activation of Ph4-nEHn (E = Si, Ge; n = 1-3) and pinacolborane (HBpin) is discussed. Unlike previous reports, both types of isomers, the hydride [PC(EHn-1Ph4-n)P]PdH or [P...

Fe16N2 fine particles were prepared by reduction in 5% H2/Ar gas mixture flow, starting from goethite or hematite precursors, followed by nitridation in ammonia gas flow. Small amounts of metallic iron and iron oxide are present besides the main phase which is an ordered iron nitride having martensite structure (α’’-Fe16N2) as revealed by Mössbauer...

The reactivity of a nucleophilic palladium carbene, [PC(sp2)P]Pd(PMe3) (1; [PC(sp2)P] = bis[2-(diisopropylphosphino)phenyl]methylene), toward the C–H bonds of CH3COCH3, CH3CN, Ph–CCH, fluorene, and 9,10-dihydroanthracene was investigated. All surveyed substrates reacted with 1. However, there was no detectable reaction of 1 with Ph2CH2. It is propo...

A series of palladium(ii) radical carbene complexes, [PC˙(sp2)P]PdI, [PC˙(sp2)P]PdBr, and [PC˙(sp2)P]PdCl (PC(sp3)H2P = bis[2-(di-iso-propylphosphino)-phenyl]methane), is described. Compound [PC˙(sp2)P]PdI dimerizes to {[PC(sp2)P]PdI}2 in the solid state, akin to the formation of Gomberg's dimer. While the bromo and the iodo derivatives could be ob...

The reactions of two nucleophilic palladium carbene complexes with the strong Lewis acid B(C6F5)3 afforded two zwitterionic products. One of them features a remote nucleophilic attack at the para-carbon of the supporting ligand, while the other indicates C-F activation of B(C6F5)3. Both behaviours are reminiscent of the reactivity of frustrated Lew...

Two formal palladium carbene complexes, [PC(sp2)P]Pd(PR3) ([PC(sp3)HP] = bis[2-(di-isopropylphosphino)-phenyl]methyl, iPr2P-C6H4-CHC6H4-PiPr2, 3: R = Me; 4: R = Ph), were isolated and characterized. Structural studies and DFT calculations indicate that the interaction between palladium and carbon is best described as a single bond, associated with...

The structure of catena-poly[[potassium-tri-μ-di­methyl­acetamide-κ⁶O:O] iodide], {[K(C4H9NO)3]I}n, at 120 K has trigonal (P-3) symmetry. The structure adopts a linear chain motif parallel to the crystallographic c axis. Two crystallographically independent K⁺ cations are present in the asymmetric unit located on threefold rotoinversion axes at [0,...

The structure of catena-poly[[potassium-tri-µ-dimethylacetamide-k6O:O]iodide], {[K(C4H9NO)3]I}n, at 120 K has trigonal (P3) symmetry. The structure adopts a linear chain motif parallel to the crystallographic c axis. Two crystallographically independent K+ cations are present in the asymmetric unit located on threefold rotoinversion axes at [0, 0,...

A series of diphosphine ligands iPr2P-C6H4-X-C6H4-PiPr2(L1: X = CH2, L2: X = CH2CH2) was investigated to determine the preference for cis/trans coordination to palladium(0), palladium(II), and rhodium(I). Increasing the length of the bridging alkyl backbone from one to two carbons changes the geometry of the resulting palladium(II) complexes, with...

Novel metal nanoporous transition metal oxides Mx Oy (Co3O4, CuO) have been synthesized by thermal decomposition of inorganic salts precursors (acetates, nitrates) impregnated into hexagonal mesoporous silica (OMS, ordered mesoporous silica) of SBA-15 type (prepared in-house) at different precursor loadings, the mesocomposites thus obtained being m...

In this paper, we present inorganic–organic hybrid coatings with polymer matrix (water soluble) that contain silver nanoparticles (AgNPs). The structure and morphology of coating materials were determined by infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Therefore, the antimicrobial activities and mechanisms of coatings for s...

The hydrogen storage material lithium borohydride was infiltrated from solvent solution into the pores of the carbon replica of MSU-H mesoporous silica by the incipient wetness method. Different amounts of lithium borohydride up to 40 % from the weight of the high surface area carbonic material were used. By this method was achieved a good dispersi...

Mesoporous carbon frameworks were synthesized using the soft-template method. Ca(BH(4))(2) was incorporated into activated mesoporous carbon by the incipient wetness method. The activation of mesoporous carbon was necessary to optimize the surface area and pore size. Thermal programmed absorption measurements showed that the confinement of this bor...

In this work zinc oxide, ZnO, nanopowders were synthesized by co-precipitation method from a zinc acetate, Zn(CH3COO)(2), solution. The obtained nanoparticles were morphologically and structurally characterized by XRD diffraction, SEM, IR and UV-Vis spectroscopy. The new obtained material was investigated as an additive in coatings for improving we...

In this paper 2 new nanosized organic-inorganic hybrid silica based materials have been synthesised by the sol gel process in the presence of different surfactant mixture systems (non-ionic and cationic). The hybrid silica materials have been tested as supports for lipase immobilisation by using a cross-linking method with the glutaraldehyde as a c...

The present paper presents the synthesis and characterization of some new functionalized SBA-15 silica, by an improved synthesis route leading to well-organized mesoporous materials belonging to p6mm symmetry group. In a one-pot co-condensation synthesis we obtained and characterized SBA-APTMS and SBA-APTES samples. Variation of the initial APTMS/T...

The purpose of this study is the preparation and characterization of organic-inorganic hybrid materials used for enzyme immobilization on silica-based support by cross-linking method. The cross-linking agent used was glutaraldehyde and the enzyme used for immobilization was lipase. Organic-inorganic hybrid materials were obtained by the sol-gel pro...

In this paper we present our results obtained on tuning the synthesis parameters for obtaining pure mesoporous silica of SBA-15 type. We have investigated the influence of NaCl added in the reaction mixture (in different quantities) and the role of the synthesis temperature and hydrothermal treatment on the properties of the final siloxanic materia...

Lithium borohydride (LiBH4) is a promising material for hydrogen storage, featuring a high gravimetric storage density (above 13 wt. % in the first decomposition step). However, studies of re-hydrogenation of the decomposition products have proven less successful, leading us to the requirement of modified-LiBH4 materials with better absorption-deso...