Milan Alberti

Laser ablation synthesis of new phosphorus nitride clusters from α‐P3N5 via laser desorption ionization and matrix assisted laser desorption ionization time‐of‐flight mass spectrometry

Phosphorus nitride clusters generated during Laser Desorption Ionization (LDI) and Matrix-Assisted Laser Desorption Ionization (MALDI) of solid P(3) N(5) were analyzed via Time-of-Flight Mass Spectrometry (TOF MS). The LDI TOF mass spectra show the formation of series of clusters: P(m)N(n)(+) {(m=1; n=8-11), (m=4; n=3-4), (m=5; n=1-5), (m=6; n=1-3, 5-8), (m=2-7; n=1), (m=5-10; n=2), (m=4-6; n=3), (m=4,5; n=4), (m=5,6; n=5)}, and P(m)N(n)(-) (m=4,5; n=1). Using 3-hydroxypicolinic acid (HPA) as a matrix the P(m)N(n)(+) species (m=1-4, 6, 8) with a high nitrogen content (n=4, 5, 8, 10-12, 20) were identified. The formation of a N(6)(-) cluster was also detected using a C(60) matrix. Under various conditions singly charged P(m)(+) (m=2-7, 9, 13), P(m)(-) (m=3-11, 13, 15, 17), N(n)(+) (n=5, 9, 10, 12, 13), and N(n)(-) (n=6, 10-15) clusters were identified in the mass spectra. Such high nitrogen content clusters (up to N(15)(-)) generated by laser desorption from a solid material are described for the first time. The stoichiometry of the P(m)N(n) clusters was determined via isotopic envelope analysis and computer modelling. The composition of the clusters with respect to the crystalline structure of α-P(3)N(5) is discussed.

Laser ablation synthesis of phosphorus sulphides, selenides and ternary PpSqSer clusters from various precursors

Laser ablation (LA) synthesis with simultaneous time-of-flight mass spectrometric (TOF MS) analysis was used to examine the formation and composition of ternary Pp Sq Ser clusters. Clusters formed by LA of various precursors are singular, binary and ternary. Formation of negative or positive singly charged Pp, Sq and Ser clusters, where Pp + (p = 1-249), Pp* (p = 1-191), Sq* (q = 1-15), Sq + (q = 1-12), Ser* (r = 1-8) and Ser+ (r = 1-9), was identified. High numbers of binary Pp Sq, Sq Ser (35) or ternary Pp Sq Ser (138) clusters were formed by LA synthesis from the various mixtures. Most of the ternary Pp Sq Ser clusters were formed either from a mixture of P4S3 with selenium (grey) or from a mixture of SeS2 with red phosphorus. In total, 138 new ternary Pp Sq Ser clusters were identified. The conditions for the formation of such possible prospective nano-materials are given.

Novel electrospun gelatin/oxycellulose nanofibers as a suitable platform for lung disease modeling

Novel hydrolytically stable gelatin nanofibers modified with sodium or calcium salt of oxycellulose were prepared by electrospinning method. The unique inhibitory effect of these nanofibers against Escherichia coli bacteria was examined by luminometric method. Biocompatibility of these gelatin/oxycellulose nanofibers with eukaryotic cells was tested using human lung adenocarcinoma cell line NCI-H441. Cells firmly adhered to nanofiber surface, as determined by scanning electron microscopy, and no signs of cell dying were detected by fluorescent live/dead assay. We propose that the newly developed gelatin/oxycellulose nanofibers could be used as promising scaffold for lung disease modeling and anti-cancer drug testing.

Laser ablation synthesis of new gold arsenides using nano-gold and arsenic as precursors. Laser desorption ionisation time-of-flight mass spectrometry and spectrophotometry

RATIONALE Currently, a limited number of gold arsenides have been described, some of which have important industrial applications, Laser ablation synthesis (LAS) has been employed in an attempt to generate some novel gold arsenide compounds. METHODS LAS of gold arsenides was performed using nano-gold (NG) and arsenic as precursors. The clusters formed during laser desorption ionisation (LDI) were analysed by mass spectrometry using a quadrupole ion trap and reflectron time-of-flight analyser to determine the stoichiometry. UV/VIS spectrophotometry was used to follow possible hydrothermal synthesis of gold arsenides. RESULTS LAS of NG yielded singly charged gold clusters Aum (+(-)) (m = 1-35). LAS of bulk arsenic and nano-arsenic produced Asn (+(-)) clusters with n = 2-10 and n = 2-20, respectively. Laser ablation of Au-As nano-composites or NG-As mixtures generated Aum (+(-)) (m = 1-12), Asn (+(-)) (n = 3-4), and several series of Aum Asn (+(-)) (m = 1-60, n = 1-18) clusters. Over 450 species of gold arsenide clusters and 212 mixed chlorinated Aum Asn Clx clusters were detected and their stoichiometry determined. CONCLUSIONS Many new gold arsenides were synthesised via LAS for the first time with Au-As composites and NG-As mixtures of different Au:As ratios using mass spectrometry to determine cluster stoichiometry. The resolved stoichiometry of Aum Asn clusters determined in this study could accelerate the development of advanced Au-As nano-materials.

Generation of new Agm Ten clusters via laser ablation synthesis using Ag-Te nano-composite as precursor. Quadrupole ion trap time-of-flight mass spectrometry.

RATIONALE Metal tellurides have applications in various fields of science and technology but only a few gold-silver tellurides have been reported. The laser ablation synthesis (LAS) method allows the preparation of nano-materials from solid substrates. Therefore, this method was selected to synthesise some gold-silver tellurides. METHODS Laser desorption ionisation quadrupole ion trap time-of-flight mass spectrometry (LDI QIT TOF MS) was used for the generation of new Au(p)Ag(q)Te(r) clusters. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to characterise the materials. The stoichiometry of the clusters generated was determined via collision-induced dissociation (CID) and modeling of isotopic patterns. RESULTS Chemisorption of gold and silver nano-particles on tellurium powder led to the formation of a new kind of Au-Ag-Te nano-composite. The LDI of this nano-composite yielded nine unary (Ag(q), Te(r)), 40 binary (Au(p)Te(r) and Ag(p)Te(r)) and 78 ternary clusters. The stoichiometry of these novel Au(p)Ag(q)Te(r) clusters is reported here for the first time. CONCLUSIONS The new Au-Ag-Te nano-composite was found to be a more suitable precursor for the generation of clusters than the mixtures of the elements. TOF MS was shown to be a useful technique for following the generation of gold-silver tellurides. Knowledge of the cluster stoichiometry could accelerate the further development of novel high-tech materials such as chalcogenide glasses.

Plasma-chemical modifications of cellulose for biomedical applications

Abstract A 6-carboxycellulose (in medicine known as “oxidized cellulose” or “oxycellulose”) is one of the cellulose derivatives popular in the field of surgery. Health products based on oxidized cellulose are great local hemostatics with unique bactericidal and fully bioabsorbable effects. Traditional process of native cellulose oxidation is described as a complex radical reaction in strong acidic liquid medium doped by toxic nitrous radicals (NO*). Our plasma-chemical reaction demonstrates a new synthesis method of oxidized cellulose with unique bactericidal effect. This plasma-chemical treatment is based on atmospheric plasma discharge in liquid medium leading to the oxidation of polysaccharide molecules resulting in oxycellulose. Final oxycellulose properties were evaluated by infrared spectroscopy and carboxyl content determination. The biological impact showed a strong germicidal effect. Graphical Abstract

Laser Desorption Ionization of As2Ch3 (Ch = S, Se, and Te) Chalcogenides Using Quadrupole Ion Trap Time-of-Flight Mass Spectrometry: A Comparative Study

AbstractLaser desorption ionization using time-of-flight mass spectrometer afforded with quadrupole ion trap was used to study As2Ch3 (Ch = S, Se, and Te) bulk chalcogenide materials. The main goal of the study is the identification of species present in the plasma originating from the interaction of laser pulses with solid state material. The generated clusters in both positive and negative ion mode are identified as 10 unary (Sp+/– and Asm+/–) and 34 binary (AsmSp+/–) species for As2S3 glass, 2 unary (Seq+/–) and 26 binary (AsmSeq+/–) species for As2Se3 glass, 7 unary (Ter+/–) and 23 binary (AsmTer+/–) species for As2Te3 material. The fragmentation of chalcogenide materials was diminished using some polymers and in this way 45 new, higher mass clusters have been detected. This novel approach opens a new possibility for laser desorption ionization mass spectrometry analysis of chalcogenides as well as other materials. Graphical abstractᅟ

Laser Ablation Synthesis of Gold Selenides by using a Mass Spectrometer as a Synthesizer: Laser Desorption Ionization Time-of-Flight Mass Spectrometry.

Methods for the rapid construction of new chemical motifs have the potential to accelerate the development of nanoscience. The synthesis of new chemical entities by laser ablation has been systematically demonstrated by using mixtures of gold and selenium. The compounds generated are detected by time-of-flight mass spectrometry and, for selected compounds, the structure is investigated by using density functional theory optimization. In total, 67 new gold selenide clusters have been synthesized, demonstrating an unsuspected richness in gold chemistry. Chemical species generated in the gas phase might inspire new routes for the synthesis of novel compounds in the solid state.

Laser ablation generation of clusters from As-Te mixtures,As-Te glass nano-layers and from Au-As-Te nano-composites.Quadrupole ion trap time-of- flight mass spectrometry

RATIONALE Arsenic tellurides have found important applications in various fields of science, but only a few gold-arsenic tellurides have been reported. Laser ablation synthesis (LAS), a suitable method for the generation of new compounds, has been used to generate clusters from As-Te mixtures, an As-Te glass and Au-As-Te nano-composites. METHODS Chalcogenide glass nano-layers prepared via Physical Vapour Deposition - thermal evaporation were characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). LAS with laser desorption ionisation quadrupole ion trap time-of-flight mass spectrometry (LDI QIT TOFMS) was used for the generation and analysis of new AuxAsmTen clusters. The stoichiometry of the clusters was determined via isotopic envelope modelling. RESULTS A simple procedure for the preparation of the Au-As-Te nano-composite was developed. From As-Te mixtures only five binary AsmTen clusters were generated, while from a glass layer 10 binary AsmTen clusters were identified, because during the deposition of the glass the elements reacted with each other to form a complex three-dimensional (3D) structure. Using LAS on the Au-As-Te nano-composite leads to the formation of six unary Ten (n = 1-6), 16 binary (AsmTen and AuxTen), and 31 ternary AuxAsmTen clusters. CONCLUSIONS LAS was demonstrated to be a useful technique for the generation of AuxAsmTen clusters in the gas phase. More AsmTen clusters were generated from the deposited glass layers than from As-Te mixtures. Most of the ternary AuxAsmTen clusters generated from the nano-composite are reported here for the first time.

The reaction of P3N3Cl5NH2 with SOCl2: the crystal structures of P3N3Cl5NSO and Cl5N3P3OP3N3Cl5

Abstract Depending on reaction conditions, the reaction of P3N3Cl5NH2 with SOCl2 gives four compounds: P3N3Cl5NSO, P3N3Cl5NSNP3N3Cl5, P3N3Cl5NSCl2 and P3N3Cl5OP3N3Cl5. The reaction course and the composition of the reaction mixture can be easily monitored by 31P NMR spectroscopy. P3N3Cl5NSO and P3N3Cl5OP3N3Cl5 were isolated in the form of single crystals and their structures have been determined by X-ray structure analysis. The vibrational spectra of P3N3Cl5NSO, P3N3Cl5NSNP3N3Cl5 and P3N3Cl5NSCl2 are also briefly discussed.