Claudia Graiff

University of Parma | UNIPR · Department of Chemistry, Life Sciences and Environmental Sustainability

Chemical reduction of a dinuclear [(di‐NHC)Au2Cl2(di‐NHC)] complex (NHC=imidazol‐2‐ylidene), using excess NaBH4 as reducing agent in presence of dichloromethane (DCM) as solvent, provides a molecular cluster with formula [Au13(di‐NHC)5(CH3)2]Cl3, exhibiting covalent bonds between gold atoms of the cluster core and methyl groups. The presence of Au‐...

N-methylation of amines is of great interest in the synthesis of pharmaceuticals and valuable compounds, and the possibility to perform this reaction with an inexpensive and non-toxic substrate like CO2...

This work deals with the development of innovative cement-free plastering mortars with enhanced thermal properties. To this end, one-part alkali-activated slag-based materials were manufactured, by adding aluminum powder as expanding agent to reduce the density and expanded glass to improve thermal insulation. Different recipes were developed by va...

Gypsum has been widely used in traditional and monumental architecture in many countries of the Mediterranean area; however, due to its low water resistance and low mechanical strength, it can be subject to physical, chemical and biological degradation. To improve the preservation of gypsum-based plaster artifacts, a new hybrid inorganic-organic hy...

Platinum( ii ) cyclometalated N -alkyloxyimidazol-2-ylidene complexes with β-diketonate auxiliary ligands, [(C NOHC ^C*)Pt(L∩L)], and a gold( i ) N -alkyloxyimidazol-2-ylidene complex [(C NOHC )AuBr] were synthesized and fully characterized.

Self-cleaning and hydrophobic treatments based on TiO2 and SiO2 nanoparticles are widely applied for the preservation of cultural heritage materials, to improve their resilience in polluted environments. Excellent results have been obtained on stone materials, but experiments on painted stone surfaces, such as wall paintings and polychrome plasters...

A series of six Mn(I) complexes with general formula [MnBr(bisNHC)(CO)3], having a bidentate bis(N‐heterocyclic carbene) ligand (bisNHC), has been developed by varying the bridging group between the NHC donors, the nitrogen wingtip substituents and the heterocyclic ring. The synthesis of the complexes has been accomplished by in situ transmetalatio...

Packaging waste originated from the food-drinking sector is obtained through the maceration process, which allows the separation of aluminum foil, paper, and plastic. Due to this process, paper and aluminum foil can be reused, while plastic must be disposed. This paper aims to reuse the disposed plastic coming from this process as additive modifier...

The fight against climate changes has encouraged the development of most research on new binders, with the aim of progressively reducing the use of Ordinary Portland Cement, with its huge carbon footprint. Within this context, geopolymer-like binders can represent an eco-friendly alternative, also for the production of mortars for masonry buildings...

Gold(i) triarylphosphane compounds are a well-known class of coordination compounds displaying from mild to strong emissive properties. Mechanochemical approaches to the preparation, spectroscopic characterization, X-ray diffraction structural determination, and photophysical studies of green emissive neutral linear monophosphane or neutral pseudo-...

Two antimicrobial agents such as silver nanoparticles (AgNPs) and titanium dioxide (TiO2) have been formulated with natural polysaccharides (chitosan or alginate) to develop innovative inks for the rapid, customizable, and extremely accurate manufacturing of 3D-printed scaffolds useful as dressings in the treatment of infected skin wounds. Suitable...

In this work, we present a diagnostic study carried out on 20th century wall paintings in the Chapel of the Fallen of the Great War in the Cathedral of Parma (Italy). The Chapel was painted in the two-year period of 1921–1922 and has been recently restored. The paintings were investigated in order to study the technique used by the painter, Biagio...

Two antimicrobial agents such as silver nanoparticles (AgNPs) and titanium dioxide (TiO2) have been formulated with natural polysaccharides (chitosan or alginate) to develop innovative inks for the rapid, customizable, and extremely accurate manufacturing of 3D printed scaffolds useful as dressings in the treatment of infected skin wounds. Suitable...

Herein, we report a new method to synthesize molecular gold nanoclusters (AuNCs) stabilized by phosphine (PR3) and di-N-heterocyclic carbene (di-NHC) ligands. The interaction of di-NHC gold(I) complexes, with the general formula [(di-NHC)Au2Cl2] with well-known [Au11(PPh3)8Cl2]Cl clusters provides three new classes of AuNCs through a controllable r...

A multi-analytical approach is proposed for the detection and quantitative characterization of waxes in wall paintings from the Vesuvian area, in particular in the House of the Skeleton, the House of the Deer and the House of the two Atriums in Herculaneum (Italy). Different types of waxes, of animal, vegetable, mineral and artificial origin, were...

A series of protic N‐heterocyclic carbene ligand precursors based on theophylline or adenine has been prepared, and the reactivity and coordination chemistry of these proligands towards iridium(III) centers has been investigated. Complex formation appears to be highly dependent on the proligand structure. In one case, a particularly stable complex...

The present study introduced a novel ion-pair complex of [Co(5,5´-dmbpy)3][Ce(NO3)6] (a1) fabricated by the reaction of Co(NO3)2·6H2O, Ce(NO3)3·6H2O, NaNO3 and 5,5´-dimethyl-2,2´-bipyridine ligand. A sonochemical method was used to synthesize the nano-scale [Co(5,5´-dmbpy)3][Ce(NO3)6] (a2). The sulfite was then detected and quantified on a carbon p...

Due to the release of active pharmaceutical compounds in wastewater and their persistence in the environment, dangerous consequences can develop in the aquatic and terrestrial organisms. Chitosan/Ag/TiO2 3D printed scaffolds, at different Ag nanoparticle concentrations (10, 100, 1000 ppm) are investigated here as promising materials for photocataly...

The increase of agri-food wastes by agriculture and industries is one of the main causes of environmental pollution. Here we propose the recycling of Cynara scolymus L. wastes to obtain polymorph II cellulose nanocrystals (CNC). Two different extraction procedures are compared: (i) Soxhlet extraction in an ethanol/toluene mixture, and (ii) water bo...

The A2A adenosine receptor (A2AAR) is one of the four subtypes activated by nucleoside adenosine, and the molecules able to selectively counteract its action are attractive tools for neurodegenerative disorders. In order to find novel A2AAR ligands, two series of compounds based on purine and triazolotriazine scaffolds were synthesized and tested a...

We report on the synthesis of a novel class of functionalized thia[6]helicenes and a thia[5]helicene, containing a benzothiophene unit and a second heteroatom embedded in the helix (i.e., nitrogen and oxygen) or a pyrene or a spirobifluorene moiety. These systems are obtained through straightforward and general procedures that involve: (i) palladiu...

Coinage metal cyclic trinuclear compounds (CTCs) are an emerging class of metal coordination compounds that are valuable for many fine optoelectronic applications, even though the reactivity dependence by the different bridging ligands remains somewhat unclear. In this work, to furnish some hints to unravel the effect of substituents on the chemist...

This work focuses on the development and on the mechanical characterization of geopolymer composites to be used as sustainable plasters or mortars. The starting point of the work is the synthesis of a geopolymer binder, which is subsequently used for the production of two different mortars: the first one is obtained by simply adding fine aggregates...

A series of gold(I) and gold(III) complexes with N‐heterocyclic carbene ligands functionalized with a pendant thioether group (NHC‐SR) was synthesized with straightforward procedures and characterized in solution with NMR spectroscopy and ESI‐MS spectrometry, as well as in the solid state by means of single crystal X‐ray diffraction analysis. Selec...

A small library of dinuclear gold(I) complexes with the title ligands has been prepared, encompassing neutral, mono- and dicationic complexes. The luminescence properties of the complexes in the solid state have been evaluated, and it turns out that neutral and monocationic complexes not presenting a rigid metallamacrocyclic structure can exhibit r...

The new Co(II) compound [Co(5,5′-dmbpy)2(NCS)2] (a1) was prepared by reacting Co(NO3)2·6H2O, 5,5′-dimethyl-2,2′-bipyridine ligand, and Na(SCN). The nano-scale size of [Co(5,5′-dmbpy)2(NCS)2] (a1) was synthesized using sonochemical process. The size of the nanoparticles (a2) was ∼13 ± 2 nm. We have also provided a new platform of electrochemical sen...

Two new gold(I) complexes with a di(N-heterocyclic carbene) ligand (diNHC) derived from caffeine have been synthesised by a base-assisted metalation of the appropriate di(azolium) salt in the presence of the gold precursor AuCl(SMe2). Under kinetically controlled conditions, the reaction affords a mononuclear cationic complex with the diNHC ligand...

The Front Cover Feature shows the spectacular curved staircase of the Vatican Museums designed by Giuseppe Momo and opened in 1932, as background of our synthetic methodologies aimed to convert atropoisomer species based on benzodithiophenes into chiral helical‐shaped tetrathiahelicenes. The helix staircase recalls the peculiar topology of tetrathi...

Efficient and versatile synthetic routes to functionalized tetrathia[7]helicenes (7‐THs) are described. The key intermediates of these methodologies are 2‐bromo‐3,3′‐bibenzo[1,2‐b:4,3‐b′]dithiophenes (1), synthesized through a palladium‐catalyzed homocoupling reaction between two benzo[1,2‐b:4,3‐b′]dithiophene units followed by a regioselective α‐b...

Color is one of the most fascinating aspects of Nature; it is part of the beauty of the environment that surrounds us, playing a key role in the acceptability of most products used in our society [...]

Polyamidoamines are low cost and easily synthesized materials that may find applications in cations sequestration and water treatment. In this paper a new amido-aminoacid ligand containing methionine has been designed as a monomeric model of the corresponding polyamidoamine. The amido-aminoacid ligand has been synthesized in high yield, by reacting...

We report that dihalogeno‐substituted benzodithiophenes (BDTs) undergo a smooth ligand‐free Suzuki–Miyaura cross‐coupling reaction, under air and moderate heating (60 °C), with aryl‐, alkenyl‐ and alkynyltrifluoroborate salts in a biodegradable choline chloride‐based eutectic mixture, thereby granting access to valuable π‐conjugated BDT compounds (...

Crystal structure prediction is the holy grail of crystal engineering and is key to its ambition of driving the formation of solids based on the selection of their molecular constituents. However, this noble quest is hampered by the limited predictability of the incorporation of solvent molecules, first and foremost the ubiquitous water. In this co...

Here, a formulation of silver nanoparticles (AgNPs) and two natural polymers such as alginate (ALG) and nanocrystalline cellulose (CNC) was developed for the 3D printing of scaffolds with large surface area, improved mechanical resistance and sustained capabilities to promote antimicrobial and cytotoxic effects. Mechanical resistance, water content...

The synthesis of novel iridium (III) complexes of general formula [IrClCp*(diNHC)](PF6), with chelating di (N-heterocyclic carbene) ligands (diNHC) is reported. The obtained complexes differ for the wingtip substituents at the nitrogen atom of the heterocycles (Me, t-Bu, Cy, n-oct), the linker between the carbene donors (-CH2-, –CH2CH2-, –CH2CH2CH2...

Three novel gold(III) complexes with bidentate di(N-heterocyclic carbene) (diNHC) ligands of general formula [AuL2](PF6)3 (L = diNHC) were isolated by transmetallation of the carbene ligand from the corresponding silver(I) complexes [Ag2L2](PF6)2 to KAuBr4 in the presence of AgPF6. In this regard, the scope of ligand stereo-electronic properties ha...

Iridium complexes [IrClCp*diNHC]PF6, with N-heterocyclic dicarbene (diNHC) and pentamethylcyclopentadienyl (Cp*) ligands, have been investigated in light driven water oxidation catalysis within the Ru(bpy)32+/S2O82- cycle (bpy = 2,2’-bipyridine). In particular, the effect of different diNHC ligands was evaluated by employing the complex 1a (diNHC =...

A series of six dinuclear gold(I) complexes with bridging bidentate N-heterocycic carbene ligands (NHCs) of general formula Au2Br2LX (L = diNHC, X = 1–6) have been studied as catalysts in the intermolecular hydroalkoxylation of terminal and internal alkynes. The best catalytic results have been obtained by using Au2Br2L4, characterized by 2,6-diiso...

Waste paper is an environmentally friendly source of cellulosic material. Here we propose a new treatment based on nanocrystalline cellulose (CNC) for paper preservation and consolidation. Suspensions of CNC were prepared by sulfuric acid hydrolysis using waste paper as cellulose source (CNCWP) and compared with CNC from cotton linter (CNCCL). Both...

Polysubstituted phthalimide derivatives have been isolated in excellent yield from the addition reaction between acetoacetanilide and dialkyl acetylenedicarboxylates by using DABCO as an efficient basic catalyst in EtOH at room temperature. This procedure led to the formation of new phthalimide derivative in the presence of di-tert-butylacetylendic...

N-phosphine oxide-substituted imidazolylidenes (POxIms) have been employed as heteroditopic ligands towards gold centres. Both bis-carbene and mono-carbene gold(I) complexes have been obtained, depending on the steric bulk of the employed POxIm ligand. Oxidation of the gold(I) complexes with halogens or halogen synthons allows access to both bis-ca...

TiO2-supported chitosan scaffolds (TiO2/CS) are here proposed as promising material for wastewater treatment, in particular for the removal of pharmaceutical compounds. TiO2/CS are tested for the amoxicillin photodegradation under UV/Vis irradiation. Amoxicillin (AMX) is an antibiotic of the beta-lactam family. Due to the release of antibiotics in...

A new complex with the formula [La(5,5′-dmbpy)2(NO3)3] (a) [where (5,5′-dmbpy = 5,5′-dimethyl-2,2′-bipyridine)] has been synthesized. The compound was characterized by cyclic voltammetry, elemental analysis and spectroscopic methods (IR, UV–Vis, ¹H-NMR). Single crystals adapted for X-ray diffraction analysis were recorded by slow crystallization fr...

Linear poly(amidoamine)s (PAAs), functionalized in the main chain with hydroxyl and/or siloxane groups, were obtained by single step addition of primary amines (ethanolamine, 3-aminopropyltriethoxysilane) to N,N’-methylenebisacrylamide, in water or low molecular weight alcohols, without catalysts. The polymers were characterized by FTIR, Raman, ¹H...

Novel silver(I), gold(I), and palladium(II) complexes were synthesized with bidentate heteroditopic carbene ligands that combine an imidazol-2-ylidene (nNHC) with a 1,2,3-triazol-5-ylidene (tzNHC) connected by a propylene bridge. The silver(I) and gold(I) complexes were dinuclear species, [M 2 (nNHC-tzNHC) 2 ](PF 6 ) 2 (M = Ag or Au), with the two...

We report on a single-step procedure for the synthesis of dinuclear gold(I) complexes with bridging di(N-heterocyclic carbene) (diNHC) ligands of general formula Au2Br2L¹⁻⁹ (L = diNHC). The obtained complexes differ in the bridging group between the carbene donors and in the terminal wingtip substituents at the imidazol-2-ylidene rings. The complex...

Novel bio-inspired materials derived from crystalline nanocellulose (CNC) have been tested as wood consolidants. A suspension of CNC, produced by acid hydrolysis of cellulose and used as such or mixed with lignin and/or siloxane derivatives (PDMS), was applied on rotted wood samples of Norway spruce. X-Ray diffraction analysis on CNC powder showed...

Single crystals of Na[VO(SeO3)(HSeO3)]·1,5H2O have been prepared by solvent slow evaporation from an equimolar aqueous mixture of sodium selenite and vanadyl sulfate. The overall arrangement consists of VO6 octahedra, [SeO3]2− and [HSeO3]− anions forming a strong backbone with channel-like voids, while sodium cations participate in the framework, e...

Two unprecedented solid phases involving the 3,7-bis­(di­methyl­amino)­pheno­thia­zin-5-ium cation, i.e. methyl­ene blue (MB⁺), have been obtained and structurally characterized. In the crystals of 3,7-bis­(di­methyl­amino)­pheno­thia­zin-5-ium chloride dihydrate, C16H18N3S⁺·Cl⁻·2H2O (I) and 3,7-bis­(di­methyl­amino)­pheno­thia­zinium bis­ulfite, C...

Selenate(IV) and hydrogen selenate(IV) salts of bulky cations are very interesting compounds for synthetic and kinetic studies. In this work, bis(triphenylphosphine)iminium ([PNP]+) chloride has been used, which aims to synthesize the corresponding selenate(IV) salt by an exchange reaction in the aqueous solution and subsequent crystallization by s...

The reaction between the gold(I) dicarbene complexes [Au2(μ²-MeIm(CH2)nImMe)2](PF6)2 (Im = imidazol-2-ylidene, n = 1, 2, 3) and N-bromosuccinimide affords the gold(III) complexes [{AuBr(N-suc)}2(μ²-MeIm(CH2)nImMe)2](PF6)2, in which both gold centres have a bromide and a N-succinimidate anion in the coordination sphere. In the case of the CH2CH2 bri...

Cu(II) cations in the presence of diamine ligands such as tetramethylethylendiamine (TMEDA) react with Na2SeO3 to produce the heteroleptic selenite copper compound of formula [Cu3(TMEDA)3(SeO3)2(H2O)4](NO3)2. In the cationic moiety two copper atoms are linked by two selenite anions through the O–Se–O bridge. One of the two bridging selenite anion c...

A new approach to the synthesis of new heterocyclic compounds with benzoylisothiocyanate, amines, and 2-bromoacetophenone (phenacyl bromide) fragments in one molecule has been developed. The synthesis method comprises condensation reaction for the preparation of novel (4-phenylthiazol-2(3H)-ylidene) benzamide derivatives. These new compounds were s...

Treatment of the tricationic gold(III) [Au(MeImCH2ImMe)2](PF6)3 complex 1-3PF6 (Im = imidazol-2-ylidene) with excess halides affords complexes 1-3X (X = Cl, Br, I), resulting from counter anion PF6-/X- exchange. The 1H chemical shift of the CH3 groups and particularly of the CH2 linker in DMSO-d6 are different in the three complexes, thus suggestin...

Complexes [VO(dipic) (H2O)2]·2H2O (1), [H2Met][V2O4(dipic)2] (2) and [HGly][VO2(dipic)] (3), where H2dipic = 2,6-pyridinedicarboxylic acid, Met = Metformin (N,N-dimethylbiguanide) and Gly = glycine, were synthesized. The three complexes were characterized by elemental analysis, FTIR, ¹H and ¹³C NMR, and UV–Vis spectroscopy. Solid-state structures o...

Questo articolo si propone come un account, un resoconto dell'attività svolta nell'ultimo quinquennio dal gruppo di ricerca del prof. Predieri nel Dipartimento SCVSA UniPR (Dipartimento di Chi-mica, fino al 2016) e tesa a sviluppare materiali so-stenibili per la conservazione (restauro sostenibile [1]) di manufatti ligno-cel-lulosici. I risultati o...

The nucleophilic addition of aminophosphanes to alkyl- and aryl- isothiocyanate leads to the formation of zwitterionic thioamidyl-phosphonium (P+C(S)N−R) functional group. Within this family of compounds, EtNHC(S)Ph2P NPPh2C(S)NEt (HEtSNS) can be prepared by reacting Ph2PNHPPh2 (dppa) in EtNCS as the reaction medium [1]. HEtSNS is a versatile and c...

The ordered porosity of Metal Organic Frameworks is commonly acknowledged as the most important feature when their use in the field of host guest materials chemistry is concerned. This is indeed one of their main application, and the possibilities offered by their crystalline nature for structural studies concerning the trapped species make these m...

A convenient, one-pot, multicomponent synthesis of new (4-oxothiazolidine-2-ylidene)benzamide derivatives by unsymmetrical thioureas, various amines and methyl bromoacetate has been developed. These new compounds were characterized by IR, 1HNMR, 13CNMR, mass spectrometry, CHNS elemental analysis, and single-crystal X-ray analysis.

Two unprecedented, homoleptic Pt-1,8-naphthyridine complexes have been prepared and characterized. Reaction between 1,8-naphthyridine (napy) and a platinum(II) precursor leads to a mononuclear homoleptic platinum(II) complex with stoichiometry [Pt(napy)4](OTf)2. On the contrary, reaction between napy and a dinuclear platinum(III) precursor produces...

Metal Organic Frameworks are one of the most popular examples of crystalline functional materials. Their applications, which often rely on their tuneable porosity, catch the interest of different branches of science, e. g. pharmaceutical, environmental and energetic chemistry. On the other hand, a post synthetic modification of the as-synthesized s...

The mononuclear tricationic bis(di-N-heterocyclic carbene) gold(III) complex 1³⁺ of formula [Au(MeImCH2ImMe)2]³⁺ (Im = imidazol-2-ylidene) was successfully synthesized by transmetalation of the di(N-heterocyclic carbene) ligand from the corresponding silver(I) complex to KAuBr4. The counteranion of the gold(III) cationic complex depends on the synt...

New copper(I) and copper(II) pyrazolate compounds have been prepared by similar synthesis procedures. For the 3,5-NO2-pyrazole ligands, the dinuclear cyclic Cu(I) compound [Cu2(µ-N,N-3,5-(NO2)2pz)2(PPh3)2], 1, was the only compound isolated in high yield, while in the case of the 3,5-bis(trifluoromethyl)-pyrazole ligand a spontaneous rearrangement...

The aromatic methylene blue cation (MB(+)) shows unprecedented ligand behavior in the X-ray structures of the trigonal-planar (TP) complexes MBMCl2 (M = Cu(I), Ag(I)). The two isostructural compounds were exclusively synthesized by grinding together methylene blue chloride and MCl solids. Only in the case of AuCl did the technique lead to a differe...