Spinal manipulation does not improve short-term pain and function in persons with painful shoulder: a systematic review with meta-analysis.

PURPOSE: To investigate the benefit of spinal high-velocity low-amplitude thrust (HVLAT) in improving pain and disability in persons with painful shoulder as primary outcomes. Function, quality of life, persons (and clinicians) satisfaction, adverse events rate, and time for recovery were secondary outcomes. METHODS: A systematic review with meta-analysis was conducted and MEDLINE, CENTRAL, Embase, and PEDro until 20 September 2023 were investigated. Two thousand eight hundred and ninety-nine records were retrieved and nine studies were included. Risk of bias of included studies was assessed through the Revised Cochrane risk-of-bias tool. The certainty of evidence of the pooled results was graded with GRADE approach. RESULTS: The analysis included nine studies (441 persons). The pooled results showed non-significant differences between HVLAT versus sham in pain at pre-post follow-up (MD -0.13, 95% confidence interval (CI) -0.60; 0.35; p = 0.61, I2 = 0%), and at <4 days follow-up (SMD 0.16, 95%CI -0.16; 0.48; p = 0.34, I2 = 23%); in function at <4 days follow-up (SMD -0.29, 95%CI -0.69; 0.11; p = 0.16, I2 = 50%). The certainty of evidence ranged from low to very low. CONCLUSIONS: HVLAT was not more effective than sham in improving pain and function at pre-post and at <4 days follow-up. When used as an "add-on technique", HVLAT did not improve pain nor disability.

High-velocity low-amplitude thrust (HVLAT) manipulation is no more effective than sham in improving shoulder pain at pre-post follow-up.Clinician should not be recommended to deliver HVLAT manipulation in subjects with painful shoulder with the purpose of reducing pain intensity.However, HVLAT manipulation should be considered within a multimodal approach to address function in painful shoulder subjects.

An Experimental and Theoretical Insight into I2 /Br2 Oxidation of Bis(pyridin-2-yl)Diselane and Ditellane.

The reactivity between bis(pyridin-2-yl)diselane o Py2 Se2 and ditellane o Py2 Te2 (L1 and L2, respectively; o Py=pyridyn-2-yl) and I2 /Br2 is discussed. Single-crystal structure analysis revealed that the reaction of L1 with I2 yielded [(HL1+ )(I- )⋅5/2I2 ]∞ (1) in which monoprotonated cations HL1+ template a self-assembled infinite pseudo-cubic polyiodide 3D-network, while the reaction with Br2 yielded the dibromide Ho PySeII Br2 (2). The oxidation of L2 with I2 and Br2 yielded the compounds Ho PyTeII I2 (3) and Ho PyTeIV Br4 (6), respectively, whose structures were elucidated by X-ray diffraction analysis. FT-Raman spectroscopy measurements are consistent with a 3c-4e description of all the X-Ch-X three-body systems (Ch=Se, Te; X=Br, I) in compounds 2, 3, Ho PyTeII Br2 (5), and 6. The structural and spectroscopic observations are supported by extensive theoretical calculations carried out at the DFT level that were employed to study the electronic structure of the investigated compounds, the thermodynamic aspects of their formation, and the role of noncovalent σ-hole halogen and chalcogen bonds in the X⋅⋅⋅X, X⋅⋅⋅Ch and Ch⋅⋅⋅Ch interactions evidenced structurally.

Can Serendipity Still Hold Any Surprises in the Coordination Chemistry of Mixed-Donor Macrocyclic Ligands? The Case Study of Pyridine-Containing 12-Membered Macrocycles and Platinum Group Metal Ions PdII, PtII, and RhIII.

This study investigates the coordination chemistry of the tetradentate pyridine-containing 12-membered macrocycles L1-L3 towards Platinum Group metal ions PdII, PtII, and RhIII. The reactions between the chloride salts of these metal ions and the three ligands in MeCN/H2O or MeOH/H2O (1:1 v/v) are shown, and the isolated solid compounds are characterized, where possible, by mass spectroscopy and 1H- and 13C-NMR spectroscopic measurements. Structural characterization of the 1:1 metal-to-ligand complexes [Pd(L1)Cl]2[Pd2Cl6], [Pt(L1)Cl](BF4), [Rh(L1)Cl2](PF6), and [Rh(L3)Cl2](BF4)·MeCN shows the coordinated macrocyclic ligands adopting a folded conformation, and occupying four coordination sites of a distorted square-based pyramidal and octahedral coordination environment for the PdII/PtII, and RhIII complexes, respectively. The remaining coordination site(s) are occupied by chlorido ligands. The reaction of L3 with PtCl2 in MeCN/H2O gave by serendipity the complex [Pt(L3)(m-1,3-MeCONH)PtCl(MeCN)](BF4)2·H2O, in which two metal centers are bridged by an amidate ligand at a Pt1-Pt2 distance of 2.5798(3) Å and feature one square-planar and one octahedral coordination environment. Density Functional Theory (DFT) calculations, which utilize the broken symmetry approach (DFT-BS), indicate a singlet d8-d8 PtII-PtII ground-state nature for this compound, rather than the alleged d9-d7 PtI-PtIII mixed-valence character reported for related dinuclear Pt-complexes.

Morpholine- and Thiomorpholine-Based Amidodithiophosphonato Nickel Complexes: Synthesis, Characterization, P-N Cleavage, Antibacterial Activity and Silica Nano-Dispersion.

The reactivity of thiomorpholinium P-(4-methoxyphenyl)-N-thiomorpholin-amidodithiophosphonate (S-MorH+2)(S-Mor-adtp-) and morpholinium P-(4-methoxyphenyl)-N-morpholin-amidodithiophosphonate (O-MorH+2)(O-Mor-adtp-) towards nickel (II) dichloride hexahydrated is presented and the hydrolysis of the relevant metal complexes investigated. The hydrolytic products (S-MorH+2)2 [Ni(dtp)2]²- and (O-MorH+2)2[Ni(dtp)2]²- were characterized by means of FT-IR, 1H, and 31P NMR and XRD and the experimented P-N cleavage investigated and elucidated by means of DFT calculations. The antimicrobial activity of the neutral nickel complex [Ni(S-Mor-adtp)2] was tested against a set of Gram-positive and Gram-negative bacteria alongside with its nanodispersion in a silica matrix. The complex [Ni(S-Mor-adtp)2] did not show antibacterial activity, whilst the nano-dispersed sample [Ni(S-Mor-adtp)2]_SiO2 demonstrated inhibition to growth of Staphylococcus aureus. The nanocomposites were fully characterized by means of XRPD, TGA, SEM and dinitrogen sorption techniques.

Halogenated isophthalamides and dipicolineamides: the role of the halogen substituents in the anion binding properties.

A novel family of amide-based receptors is herein described. Specifically, the role of the halogen substituents at the aryl moieties in the anion binding properties of a series of halogenated isophthalamides and dipicolineamides (L1-L6) was investigated both in solution and in the solid state in order to evaluate the incidence of all possible different and combined weak host-guest interactions. Only L5 and L6 bearing pentafluorophenyl rings as substituents have some affinities for the set of anions studied. In particular, in the case of L5 an interesting behaviour with the formation of a non-symmetric adduct with benzoate and dihydrogen phosphate was hypothesised by 1H- and 19F-NMR spectroscopy studies in solution and confirmed by theoretical calculation. The study of the crystal structures of the receptors demonstrated that the steric hindrance determined by the halogen substituents in the receptor molecules influences the accessibility of the anions to the isophthalamide or dipicoline amide NH moieties, thus modulating the affinity for the anion guests.

Antibacterial Activity of Amidodithiophosphonato Nickel(II) Complexes: An Experimental and Theoretical Approach.

The reactions of 2,4-bis(4-methoxyphenyl)-1,3-dithio-2,4-diphosphetane-2,4-disulfide (Lawesson's Reagent, LR) with benzylamine (BzNH2) and 4-phenylbutylamine (PhBuNH2) yield benzylammonium P-(4-methoxyphenyl)-N-benzyl-amidodithiophosphonate (BzNH3)(BzNH-adtp) and 4-phenylbutylammonium P-(4-methoxyphenyl)-N-(4-phenylbutyl)-amidodithiophosphonate (PhBuNH3)(PhBuNH-adtp). The relevant nickel complexes [Ni(BzNH-adtp)2] and [Ni(PhBuNH-adtp)2] and the corresponding hydrolysed derivatives (BzNH3)2[Ni(dtp)2] and (PhBuNH3)2[Ni(dtp)2] were prepared and fully characterized. The antimicrobial activity of the aforementioned amidodithiophosphonates against a set of Gram-positive and Gram-negative pathogen bacteria was evaluated, and [Ni(BzNH-adtp)2] and [Ni(PhBuNH-adtp)2] showed antiproliferative activity towards Staphylococcus aureus and Staphylococcus haemolyticus strains. density functional theory (DFT) calculations were performed to shed some light on the activity of reported compounds related to their tendency towards P-N bond cleavage.

Photoconducting Devices with Response in the Visible-Near-Infrared Region Based on Neutral Ni Complexes of Aryl-1,2-dithiolene Ligands.

Metal bis(1,2-dithiolene) complexes belonging to the class [Ni(Ar-edt)2]x- [Ar-edt2- = arylethylene-1,2-dithiolate; Ar = phenyl, (1x-), 2-naphthyl (2x-); x = 0 and 1] were fully characterized by NMR, UV-visible-near-infrared (UV-vis-NIR), diffuse reflectance, and FT-IR spectroscopy, as well as cyclic voltammetry and single-crystal X-ray diffraction analysis. These complexes have emerged as new photoconducting materials that allowed for the development of a prototype of photodetectors with response in the vis-NIR region. The photodetecting devices showed in some cases quantum efficiencies orders of magnitude higher than those of previously reported 1,2-dithiolene systems.

The first copper(ii) complex with 1,10-phenanthroline and salubrinal with interesting biochemical properties.

The novel copper complex [Cu(phen)2(salubrinal)](ClO4)2 (C0SAL) has been synthesised and characterised. Copper(ii) is coordinated by salubrinal through the thionic group, as shown by the UV-Vis, IR, ESI-MS and tandem mass results, together with the theoretical calculations. The formed complex showed a DPPH radical scavenging ability higher than that of salubrinal alone. Studies on lipid oxidation inhibition showed that the C0SAL concentration, required to inhibit the enzyme, was lower than that of salubrinal. The inhibition of the enzyme could take place via allosteric modulation, as suggested by docking calculations. C0SAL showed a good cytotoxic activity on A2780 cells, 82 fold higher than that of the precursor salubrinal and 1.4 fold higher than that of [Cu(phen)2(H2O)](ClO4)2. Treatment with C0SAL in SKOV3 ovarian cancer cells induced expression of GRP-78 and DDIT3 regulators of ER-stress response. The cytotoxic effect of C0SAL was reverted in the presence of TUDCA, suggesting that C0SAL induces cell death through ER-stress. In A2780 cells treated with C0SAL γ-H2AX was accumulated, suggesting that DNA damage was also involved.

[9]aneN3-based fluorescent receptors for metal ion sensing, featuring urea and amide functional groups.

We describe here the synthesis and coordination properties of three new derivatives of [9]aneN3 containing phenyl/quinoline pendant arm derivatives (L1, L2 and L3, respectively) also featuring urea (L1-L2) or amide (L3) functions as "non-innocent" spacers. At first, L1, L2 and L3 were studied considering the interaction with a series of anions (AcO-, BzO-, H2PO4-, F-, and Cl-) by means of 1H NMR measurements. Subsequently, the optical responses of L2 and L3 in the presence of several metal ions Cd2+, Co2+, Cu2+, Fe3+, Hg2+, K+, Mg2+, Mn2+, Ni2+, Zn2+ and Pb2 were analysed in MeCN/H2O (4 : 1 v/v). As observed by spectrophotometric and spectrofluorimetric titrations, there were significant changes in the absorbance and fluorescent emission of L2 upon addition of increasing amounts of Cd2+, Zn2+, Pb2+ and Cu2+ in MeCN/H2O (4 : 1 v/v). In particular, titrations of L2 with Cd2+, Zn2+ or Pb2+ showed an almost comparable CHEF effect up to an M2+/L2 molar ratio of 1. Overall, no significant optical selectivity was observed in the case of L2. Conversely, L3 revealed an OFF-ON selective response only in the presence of the Zn2+ ion in MeCN/H2O (4 : 1 v/v), which can be attributed to the formation of both 1 : 1 and 1 : 2 metal-to-ligand complexes, as also confirmed by potentiometric measurements. Finally, crystals of [ZnL1(Ac)](Ac) (1), [CuL1(Cl)](Cl)·H2O (2) and [CuL3](NO3) (3) were grown and analysed by X-ray diffraction. 1 and 3 feature the metal center in a pseudo-octahedral coordination geometry coordinated also by the carbonyl group from one pendant arm, while in the case of 2, one of the six coordination sites in the final distorted octahedral geometry is occupied by the nitrogen donor from the urea group of one pendant arm.

Cisplatin, glutathione and the third wheel: a copper-(1,10-phenanthroline) complex modulates cisplatin-GSH interactions from antagonism to synergism in cancer cells resistant to cisplatin.

The antagonistic effect of glutathione (GSH) against the cytotoxicity of cisplatin was observed in both wild type and cisplatin-resistant human leukaemia and ovarian carcinoma cell lines. The simultaneous presence of the cytotoxic copper complex [Cu(phen)2(OH2)](ClO4)2 (C0) restored the sensitivity of the cells to cisplatin, and, at selected concentrations, led to strong synergistic effects. The C0-cisplatin-glutathione system showed a synergistic toxic effect even in the presence of 1000 µM GSH. The three-drug cocktail exerted a higher potency against leukemic cells than against freshly isolated lymphocytes from healthy donors. Compared to actively proliferating normal lymphocytes, leukaemia cells were much more susceptible to the cytocide effect of the three-drug combination and underwent the dying process(es) much faster. When the ovarian carcinoma cells were treated with cisplatin, alone or in combination with C0, late apoptotic effects were mainly observed, suggesting that DNA interactions with the C0-cisplatin complex trigger a process of programmed cell death. In contrast, the ternary combination induced apoptotic effects similar to that shown by C0 in single treatment, that is, early apoptosis. One possible explanation is that C0 and cisplatin compete for GSH-binding in the culture medium. GSH in combination with C0 and cisplatin caused a significant induction of the apoptotic process(es), through a pathway which does not compromise the integrity of the plasma membrane of cells.

Mass spectrometric discrimination of phospholipid patterns in cisplatin-resistant and -sensitive cancer cells.

RATIONALE: Development of therapy-resistant cancer is a major problem in clinical oncology, and there is an urgent need for novel markers identifying development of the resistant phenotype. Lipidomics represents a promising approach to discriminate lipid profiles of malignant phenotype cells. Alterations in phospholipid distribution or chemical composition have been reported in various pathologies including cancer. Here we were curious whether quantitative differences in phospholipid composition between cisplatin-resistant and -sensitive model cancer cell lines could be revealed by mass spectrometric means. METHODS: The phospholipid contents of cell membranes of the cancer cell lines CCRF-CEM and A2780, both responsive and resistant to cisplatin, were analyzed by solid-phase extraction (SPE) and electrospray ionization mass spectrometry (ESI-MS and tandem mass spectrometry (MS/MS)). Extracts were obtained by disruption of cells with a dounce tissue grinder set followed by centrifugation. To minimize the enzymatic activity, phospholipids were extracted from cell extracts by SPE immediately after the cell lysis and analyzed by MS. Both supernatant and pellet fractions of cell extracts were analyzed. RESULTS: A phospholipid profile specific for cell lines and their phenotypes was revealed. We have documented by quantitative analysis that phosphocholines PC P-34:0, PC 34:1, PC 20:2_16:0, LPC 18:1 and LPC 16:0 PLs were present in the 200-400 µM concentration range in CCRF-CEM cisplatin-responsive cells, but absent in their cisplatin-resistant cells. Similarly, PC 34:1, LPC 18:1 and LPC 16:0 were increased in cisplatin-responsive A2780 cells, and PC 20:2_16:0 was downregulated in cisplatin-resistant A2780 cells. CONCLUSIONS: In this work we showed that the ESI-MS analysis of the lipid content of the therapy-resistant and -sensitive cells can clearly distinguish the phenotypic pattern and determine the potential tumor response to cytotoxic therapy. Lipid entities revealed by mass spectrometry and associated with development of therapy resistance can thus support molecular diagnosis and provide a potential complementary cancer biomarker.

Selenoureas for anion binding as molecular logic gates.

The first example of a molecular logic gate based on selenourea/anion host-guest interaction that performs a ternary logic operation using an 1H-NMR easy to read response output is described here. Selenoureas are very versatile receptors for anion binding, capable of forming both mono- and bi-coordinated adducts at room temperature in solution.

Novel coumarins and related copper complexes with biological activity: DNA binding, molecular docking and in vitro antiproliferative activity.

Coumarins show biological activity and are widely exploited for their therapeutic effects. Although a great number of coumarins substituted by heterocyclic moieties have been prepared, few studies have been carried out on coumarins containing pyridine heterocycle, which is known to modulate their physiological activities. We prepared and characterized three novel 3-(pyridin-2-yl)coumarins and their corresponding copper(II) complexes. We extended our investigations also to three known similar coumarins, since no data about their biochemical activity was previously been reported. The antiproliferative activity of the studied compounds was tested against human derived tumor cell lines and one human normal cell line. The DNA binding constants were determined and docking studies with DNA carried out. Selected Quantitative Structure-Activity Relationship (QSAR) descriptors were calculated in order to relate a set of structural and topological descriptors of the studied compounds to their DNA interaction and cytotoxic activity.

Competitive reactions among glutathione, cisplatin and copper-phenanthroline complexes.

A large number of cancers are treated with cisplatin (CDDP). However, its use is limited by drug resistance, which is often related to intracellular levels of thiol-containing molecules such as glutathione (GSH). The role of GSH in cisplatin-resistant cancer cells is still unclear. GSH may form adducts with CDDP which results in the deactivation of the drug, and, actually, a high intracellular level of GSH was observed in some cisplatin-resistant cancers. To overcome drug resistance, CDDP is often administered in combination with one or more drugs to exploit a possible synergistic effect. In previous studies, we observed that the sensitivity to CDDP of leukemic and ovarian cisplatin-resistant cancer cells was restored in the presence of [Cu(phen)2(H2O)](ClO4)2 (C0) (phen is 1,10-phenathroline). In order to clarify the possible interactions between GSH and CDDP, the reactivity and competitive reactions among CDDP, C0 and GSH in binary and ternary mixtures were studied. The investigation was extended also to [Cu(phen)(H2O)2(ClO4)2] (C10) and GSSG, the oxidized form of GSH. It was observed that CDDP was able to react with the studied copper complexes and with GSH or GSSG. However, in mixtures containing CDDP, GSH or GSSG and C0 or C10, only copper-glutathione complexes were detected, while no platinum-glutathione adducts were found.

[Au(pyb-H)(mnt)]: A novel gold(III) 1,2-dithiolene cyclometalated complex with antimicrobial activity (pyb-H=C-deprotonated 2-benzylpyridine; mnt=1,2-dicyanoethene-1,2-dithiolate).

The novel heteroleptic cyclometalated complex [AuIII(pyb-H)(mnt)] (1; pyb-H=C-deprotonated 2-benzylpyridine; mnt =1,2-dicyanoethene-1,2-dithiolate) was tested against a panel of ten Gram positive (belonging to the Staphylococcus, Streptococcus spp. and Bacillus clausii), Gram negative (E. coli, K. pneumoniae, P. aeruginosa) bacteria and three yeasts belonging to the Candida spp. Complex 1 showed a remarkable bacteriostatic antimicrobial activity against staphylococci, with Minimum Inhibitory Concentration (MIC) values of 1.56 and 3.13µg/mL for S. haemoliticus and S. aureus, respectively. Spectroscopic and electrochemical measurements, supported by Density Functional Theory (DFT) calculations, were exploited to fully investigate the electronic structure of complex 1 and its relationship with the antimicrobial activity.

A new class of silica-supported chromo-fluorogenic chemosensors for anion recognition based on a selenourea scaffold.

The first example of a chemosensor (L) containing a selenourea moiety is described here. L is able to colorimetrically sense the presence of CN- and S2- in H2O : MeCN (75 : 25, v/v). Moreover, when L is loaded into functionalised mesoporous silica nanoparticles an increase in the selectivity towards S2- occurs via a selective fluorescence response.

Fluorescent asymmetric bis-ureas for pyrophosphate recognition in pure water.

Three fluorescent asymmetric bis-urea receptors (L1-L3) have been synthesised. The binding properties of L1-L3 towards different anions (fluoride, acetate, hydrogencarbonate, dihydrogen phosphate, and hydrogen pyrophosphate HPpi(3-)) have been studied by means of (1)H-NMR, UV-Vis and fluorescence spectroscopy, single crystal X-ray diffraction, and theoretical calculations. In particular, a remarkable affinity for HPpi(3-) has been observed in the case L1 (DMSO-d6/0.5% H2O) which also acts as a fluorimetric chemosensor for this anion. Interestingly, when L1 is included in cetyltrimethylammonium (CTAB) micelles, hydrogen pyrophosphate recognition can also be achieved in pure water.

Zinc(II)-methimazole complexes: synthesis and reactivity.

The tetrahedral S-coordinated complex [Zn(MeImHS)4](ClO4)2, synthesised from the reaction of [Zn(ClO4)2] with methimazole (1-methyl-3H-imidazole-2-thione, MeImHS), reacts with triethylamine to yield the homoleptic complex [Zn(MeImS)2] (MeImS = anion methimazole). ESI-MS and MAS (13)C-NMR experiments supported MeImS acting as a (N,S)-chelating ligand. The DFT-optimised structure of [Zn(MeImS)2] is also reported and the main bond lengths compared to those of related Zn-methimazole complexes. The complex [Zn(MeImS)2] reacts under mild conditions with methyl iodide and separates the novel complex [Zn(MeImSMe)2I2] (MeImSMe = S-methylmethimazole). X-ray diffraction analysis of the complex shows a ZnI2N2 core, with the methyl thioethers uncoordinated to zinc. Conversely, the reaction of [Zn(MeImS)2] with hydroiodic acid led to the formation of the complex [Zn(MeImHS)2I2] having a ZnI2S2 core with the neutral methimazole units S-coordinating the metal centre. The Zn-coordinated methimazole can markedly modify the coordination environment when changing from its thione to thionate form and vice versa. The study of the interaction of the drug methimazole with the complex [Zn(MeIm)4](2+) (MeIm = 1-methylimidazole) - as a model for Zn-enzymes containing a N4 donor set from histidine residues - shows that methimazole displaces only one of the coordinated MeIm molecules; the formation constant of the mixed complex [Zn(MeIm)3(MeImHS)](2+) was determined.

Mixed copper-platinum complex formation could explain synergistic antiproliferative effect exhibited by binary mixtures of cisplatin and copper-1,10-phenanthroline compounds: An ESI-MS study.

Cisplatin, cis-diammineplatinum(II) dichloride, is a metal complex used in clinical practice for the treatment of cancer. Despite its great efficacy, it causes adverse reactions and most patients develop a resistance to cisplatin. To overcome these issues, a multi-drug therapy was introduced as a modern approach to exploit the drug synergy. A synergistic effect had been previously found when testing binary combinations of cisplatin and three copper complexes in vitro, namely, Cu(phen)(OH2)2(OClO3)2, [Cu(phen)2(OH2)](ClO4)2 and [Cu(phen)2(H2dit)](ClO4)2,(phen=1,10-phenanthroline, H2dit=imidazolidine-2-thione), against the human acute T-lymphoblastic leukaemia cell line (CCRF-CEM). In this work [Cu(phen)2(OH2)](ClO4)2 was also tested in combination with cisplatin against cisplatin-resistant sublines of CCRF-CEM (CCRF-CEM-res) and ovarian (A2780-res) cancer cell lines. The tested combinations show a synergistic effect against both the types of resistant cells. The possibility that this effect was caused by the formation of new adducts was considered and mass spectra of solutions containing cisplatin and one of the three copper complexes at a time were measured using electrospray ionisation at atmospheric-pressure mass spectrometry (ESI-MS). A mixed complex was detected and its stoichiometry was assessed on the basis of the isotopic pattern and the results of tandem mass spectrometry experiments. The formed complex was found to be [Cu(phen)(OH)µ-(Cl)2Pt(NH3)(H2O)](+).

Synthesis, characterization and DFT-modeling of novel agents for the protection and restoration of historical calcareous stone substrates.

The ammonium salts of oxamate (AmOxam) and monomethyloxalate (AmMeox), structurally related to ammonium oxalate (AmOx), were synthesized and characterized as protecting agents/filler for calcareous stone substrates. Both compounds featured an improved solubility in water and alcoholic-water mixtures with respect to AmOx. While AmOxam is stable in aqueous solution and reacts with calcite to afford the corresponding insoluble calcium oxamate (CaOxam), AmMeox spontaneously undergoes hydrolysis to give ammonium monohydrogen oxalate hemihydrate (AmBiox) and calcium oxalate (CaOx). Both compounds have been tested for the restoration of naturally weathered marble and biomicritic limestone. The formation of a superficial layer of CaOxam and CaOx was observed on stone samples treated with AmOxam and AmMeox, respectively, depending on the solvent mixture. A quantum-mechanical study was carried out at DFT level in order to investigate the nature of the interactions occurring between the lithic substrate (calcite) and the passivating agents, showing how the structural modifications on oxalic acid derivatives can be exploited to fine-tune their interaction with the calcite surface.