Alessandro Dolmella | Università degli Studi di Padova (original) (raw)
Papers by Alessandro Dolmella
Acta Crystallographica Section C-crystal Structure Communications, Jun 1, 2000
In the crystal of the title compound, C(10)H(12)O(2), there are two symmetry-independent molecule... more In the crystal of the title compound, C(10)H(12)O(2), there are two symmetry-independent molecules, which are essentially superimposable. Each molecule exhibits an intramolecular O-H.O hydrogen bond, with O.O separations of 2.483 (4) and 2.468 (4) A.
New Journal of Chemistry, 2018
1H-1,2,3-triazol-4-yl)pyridine p. S2 13 PLE spectra of [Ln( 2-NO 3) 3 L 2 ] (solid samples). Ln ... more 1H-1,2,3-triazol-4-yl)pyridine p. S2 13 PLE spectra of [Ln( 2-NO 3) 3 L 2 ] (solid samples). Ln = Eu, red line, emission = 616 nm; Ln = Tb, green line, emission = 545 nm.
Inorganics (Basel), Dec 31, 2019
The knowledge on element 43 (Tc) of the periodic table, built over the years through the contribu... more The knowledge on element 43 (Tc) of the periodic table, built over the years through the contributions given by the close relationship between chemistry and nuclear medicine, allowed the development of new and increasingly effective radiopharmaceuticals useful both as perfusion and target specific imaging agents for SPECT (single photon emission tomography). Among the manifold Tc-compounds, Tc(V) nitrido complexes played a relevant role in the search for new technetium-99m radiopharmaceuticals, providing efficient labeling procedures that can be conveniently exploited for the design and synthesis of agents, also incorporating small organic molecules or peptides having defined structural features. With this work, we present an overview of four decades of research on the chemistry and on the nuclear medicine applications of Tc(V) nitrido complexes.
Advances in drug research, 1994
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Several new amino-substituted aza-acridine derivatives bearing a basic side chain have been desig... more Several new amino-substituted aza-acridine derivatives bearing a basic side chain have been designed and synthesized. The antiproliferative activity of the target compounds has been evaluated against three cancer cell lines-namely HCT-116 (colorectal), the uterine sarcoma MES-SA, and its doxorubicin-resistant variant MES-SA/Dx5. A limited number of the new acridines showed marginal cytotoxicity against the tested cell lines; nevertheless, these analogues possessed a similar substitution pattern. The moderate biological activity of these derivatives was attributed to their instability in aqueous media, which has been studied by mass spectrometry and computational chemistry experiments at the density functional level of theory (DFT).
Inorganica Chimica Acta, Sep 1, 1993
![Research paper thumbnail of Synthesis, characterization and X-ray structure of [Pd(SO4)(dppp)]·H2O, a catalyst for the CO-ethene copolymerization [dppp=1,3-bis(diphenylphosphino)propane]](https://attachments.academia-assets.com/112092545/thumbnails/1.jpg)
](Inorganica Chimica Acta, Dec 1, 2005
The title complex has been synthesized by first reacting dppp with Pd(AcO) 2 in acetone and then ... more The title complex has been synthesized by first reacting dppp with Pd(AcO) 2 in acetone and then with NaHSO 4 in water. It has been characterized by IR, NMR and X-ray diffraction studies. The 31 P NMR spectrum in DMSO shows a singlet at 16.62 ppm indicating that the two P atoms are equivalent and that the sulfate anion is weakly coordinating. The X-ray structure shows that the Pd atom is surrounded in an almost regular square planar environment by the two P atoms and by two O atoms of the sulfate anion and that the neutral complex is accompanied by a water molecule of crystallization. The Pd-P distances (2.217(1) and 2.233(1)) and the P-Pd-P angle (90.78(3)°) are close to those found in other complexes where the chelating diphosphine is the same. Also the Pd-O distances and the O-Pd-O bond angle are comparable to those of other relevant chelating ligands. In MeOH, the title complex, in combination with H 2 SO 4 , catalyses the CO-ethene copolymerization. The productivity reaches a maximum upon increasing the H 2 SO 4 /Pd ratio up to ca. 470 (7650 g of polyketone/g Pd h at 90°C and 45 atm, CO/ethene 1/1). The viscosity of the polyketone passes through a maximum of 0.95 dL/g in m-cresol when the above ratio is ca. 100. It has been proposed that acid promotes the copolymerization process by destabilizing the band c-chelates intermediates involved in chain growing process, thus favoring the insertion of the monomers. At relatively high acid concentration the lowering of productivity and viscosity suggests that the sulfate anion competes with the monomers for the coordination to the metal center. In H 2 O-CH 3 COOH as a solvent the productivity strongly depends on the H 2 O/CH 3 COOH ratio, as it passes through a maximum of 12 000 g polymer/g Pd h in the presence of ca. 60% of H 2 O. The productivity is significantly lower than that found when the acetate and chloride analogues are used (27 000 g polyketone/g Pd AE h). Thus, it is likely that the sulfate anion assists significantly the copolymerization process even though the concentration of CH 3 COOH/CH 3 COO À is much preponderant.
Molecules, Apr 17, 2020
Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted p... more Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted pro-ligands and their Cu(II) complexes (1,-NH 2 ; 2,-NHMe; 3,-NHEt) have been prepared and characterized. In both the X-ray structures of 1 and 3, two crystallographically independent complex molecules were found that differ either in the nature of weakly metal-binding species (water in 1a and nitrate in 1b) or in the co-ligand (water in 3a and methanol in 3b). Electron Paramagnetic Resonance (EPR) measurements carried out on complexes 1 and 3 confirmed the presence of such different species in the solution. The electrochemical behavior of the pro-ligands and of the complexes was investigated, as well as their biological activity. Complexes 2 and 3 exhibited a high cytotoxicity against human tumor cells and 3D spheroids derived from solid tumors, related to the high cellular uptake. Complexes 2 and 3 also showed a high selectivity towards cancerous cell lines with respect to non-cancerous cell lines and were able to circumvent cisplatin resistance. Via the Transmission Electron Microscopy (TEM) imaging technique, preliminary insights into the biological activity of copper complexes were obtained.
Condensation of aryl hydrazines with ethyl pyruvate gave the respective hydrazones 4-6; Fischer i... more Condensation of aryl hydrazines with ethyl pyruvate gave the respective hydrazones 4-6; Fischer indolization led to substituted-1H-indole-2-carboxylic acid ethyl esters 7-9. The Mannich reaction of these compounds with formaldehyde and morpholine yielded ethyl 3-(morpholinomethyl)-substituted-1H-indole-2-carboxylates 10-12. The 5,7-dichloro-1H-indole-2-carbohydrazide 13 was cyclized with methyl orthoformate in DMF to give 6,8-dichloro[1,2,4]triazino[4,5-a]indol-1(2H)-one 14. Vilsmeier-Haack formylation of 7-9 gave ethyl 3-formyl-substituted-1H-indole-2carboxylates 15-17 whose 2,29-((5-chloro-2-(ethoxycarbonyl)-1H-indol-3-yl)methylene)bis-(sulfanediyl) diacetic acid 18 was prepared. The reaction of 15 and 16 with substituted anilines by conventional and microwave methods gave ethyl 3-(N-aryliminomethyl)-5-halo-1H-indole-2-carboxylates 19-29. In a cyclocondensation reaction of 19-25 with thiolactic acid or thioglycolic acid substituted indolylthiazolidinones 30-33 were prepared. Reaction of hydrazine hydrate with 15-17 did not give the respective hydrazones but directly led to the cyclized products substituted-3H-pyridazino[4,5-b]indol-4(5H)-ones 34-36, while a reaction with 2,4-dichlorophenylhydrazine yielded the uncyclized hydrazones. The chlorination of 35 and 36 with POCl 3 gave pyridazino[4,5-b]indoles 39 and 40, respectively; reaction of the latter compounds with morpholine gave 4-(substituted-5H-pyridazino[4,5-b]indol-4-yl)morpholine 41 and 42. Mannich reaction of 34 with formaldehyde and N-ethylpiperazine gave 8-chloro-3-((4-ethylpiperazin-1-yl)methyl)-3H-pyridazino[4,5-b]indol-4(5H)-one 43. The microwave assistance of selected reactions has a profound effect on the reaction speed. The structures of the new compounds were confirmed by both analytical and spectral data. Some compounds were subjected to investigations concerning their antimicrobial, tranquilizing, and anticonvulsant activities.
Nuclear Medicine and Biology, Jul 1, 2019
Journal of Organometallic Chemistry, Oct 1, 2012
The cationic complexes [Pd(h 3-C 3 H 5)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine)](X) (... more The cationic complexes [Pd(h 3-C 3 H 5)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine)](X) (2: X ¼ BF 4 À , 3: X ¼ ClO 4 À), and [Pd(h 3-2-CH 3-C 3 H 4)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)-pyridine)](BF 4 À) (4) have been synthesized by reacting the appropriate palladium-allyl precursor with 2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine in the presence of AgBF 4 or AgClO 4. The solid-state structure of 2 has been determined by single-crystal X-ray diffraction analysis. According to 1 H NMR spectroscopy the allyl protons undergo synesyn, antieanti exchange. 1 H NMR spectroscopy reveals that in acetone at temperatures lower than 223 K these complexes form aggregates the stability of which is attributed to solvophobic interactions. Complex 2 is an active catalyst for the SeM coupling of aryl bromides with phenylboronic acid; good reaction rates are obtained only with activated substrates, whereas with deactivated substrates catalyst decomposition to palladium black occurs.
Acta Crystallographica Section C-crystal Structure Communications, Jun 1, 2000
In the crystal of the title compound, C(10)H(12)O(2), there are two symmetry-independent molecule... more In the crystal of the title compound, C(10)H(12)O(2), there are two symmetry-independent molecules, which are essentially superimposable. Each molecule exhibits an intramolecular O-H.O hydrogen bond, with O.O separations of 2.483 (4) and 2.468 (4) A.
New Journal of Chemistry, 2018
1H-1,2,3-triazol-4-yl)pyridine p. S2 13 PLE spectra of [Ln( 2-NO 3) 3 L 2 ] (solid samples). Ln ... more 1H-1,2,3-triazol-4-yl)pyridine p. S2 13 PLE spectra of [Ln( 2-NO 3) 3 L 2 ] (solid samples). Ln = Eu, red line, emission = 616 nm; Ln = Tb, green line, emission = 545 nm.
Inorganics (Basel), Dec 31, 2019
The knowledge on element 43 (Tc) of the periodic table, built over the years through the contribu... more The knowledge on element 43 (Tc) of the periodic table, built over the years through the contributions given by the close relationship between chemistry and nuclear medicine, allowed the development of new and increasingly effective radiopharmaceuticals useful both as perfusion and target specific imaging agents for SPECT (single photon emission tomography). Among the manifold Tc-compounds, Tc(V) nitrido complexes played a relevant role in the search for new technetium-99m radiopharmaceuticals, providing efficient labeling procedures that can be conveniently exploited for the design and synthesis of agents, also incorporating small organic molecules or peptides having defined structural features. With this work, we present an overview of four decades of research on the chemistry and on the nuclear medicine applications of Tc(V) nitrido complexes.
Advances in drug research, 1994
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Several new amino-substituted aza-acridine derivatives bearing a basic side chain have been desig... more Several new amino-substituted aza-acridine derivatives bearing a basic side chain have been designed and synthesized. The antiproliferative activity of the target compounds has been evaluated against three cancer cell lines-namely HCT-116 (colorectal), the uterine sarcoma MES-SA, and its doxorubicin-resistant variant MES-SA/Dx5. A limited number of the new acridines showed marginal cytotoxicity against the tested cell lines; nevertheless, these analogues possessed a similar substitution pattern. The moderate biological activity of these derivatives was attributed to their instability in aqueous media, which has been studied by mass spectrometry and computational chemistry experiments at the density functional level of theory (DFT).
Inorganica Chimica Acta, Sep 1, 1993
Inorganica Chimica Acta, Dec 1, 2005
The title complex has been synthesized by first reacting dppp with Pd(AcO) 2 in acetone and then ... more The title complex has been synthesized by first reacting dppp with Pd(AcO) 2 in acetone and then with NaHSO 4 in water. It has been characterized by IR, NMR and X-ray diffraction studies. The 31 P NMR spectrum in DMSO shows a singlet at 16.62 ppm indicating that the two P atoms are equivalent and that the sulfate anion is weakly coordinating. The X-ray structure shows that the Pd atom is surrounded in an almost regular square planar environment by the two P atoms and by two O atoms of the sulfate anion and that the neutral complex is accompanied by a water molecule of crystallization. The Pd-P distances (2.217(1) and 2.233(1)) and the P-Pd-P angle (90.78(3)°) are close to those found in other complexes where the chelating diphosphine is the same. Also the Pd-O distances and the O-Pd-O bond angle are comparable to those of other relevant chelating ligands. In MeOH, the title complex, in combination with H 2 SO 4 , catalyses the CO-ethene copolymerization. The productivity reaches a maximum upon increasing the H 2 SO 4 /Pd ratio up to ca. 470 (7650 g of polyketone/g Pd h at 90°C and 45 atm, CO/ethene 1/1). The viscosity of the polyketone passes through a maximum of 0.95 dL/g in m-cresol when the above ratio is ca. 100. It has been proposed that acid promotes the copolymerization process by destabilizing the band c-chelates intermediates involved in chain growing process, thus favoring the insertion of the monomers. At relatively high acid concentration the lowering of productivity and viscosity suggests that the sulfate anion competes with the monomers for the coordination to the metal center. In H 2 O-CH 3 COOH as a solvent the productivity strongly depends on the H 2 O/CH 3 COOH ratio, as it passes through a maximum of 12 000 g polymer/g Pd h in the presence of ca. 60% of H 2 O. The productivity is significantly lower than that found when the acetate and chloride analogues are used (27 000 g polyketone/g Pd AE h). Thus, it is likely that the sulfate anion assists significantly the copolymerization process even though the concentration of CH 3 COOH/CH 3 COO À is much preponderant.
Molecules, Apr 17, 2020
Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted p... more Three new 6-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde-thiosemicarbazones-N-4-substituted pro-ligands and their Cu(II) complexes (1,-NH 2 ; 2,-NHMe; 3,-NHEt) have been prepared and characterized. In both the X-ray structures of 1 and 3, two crystallographically independent complex molecules were found that differ either in the nature of weakly metal-binding species (water in 1a and nitrate in 1b) or in the co-ligand (water in 3a and methanol in 3b). Electron Paramagnetic Resonance (EPR) measurements carried out on complexes 1 and 3 confirmed the presence of such different species in the solution. The electrochemical behavior of the pro-ligands and of the complexes was investigated, as well as their biological activity. Complexes 2 and 3 exhibited a high cytotoxicity against human tumor cells and 3D spheroids derived from solid tumors, related to the high cellular uptake. Complexes 2 and 3 also showed a high selectivity towards cancerous cell lines with respect to non-cancerous cell lines and were able to circumvent cisplatin resistance. Via the Transmission Electron Microscopy (TEM) imaging technique, preliminary insights into the biological activity of copper complexes were obtained.
Condensation of aryl hydrazines with ethyl pyruvate gave the respective hydrazones 4-6; Fischer i... more Condensation of aryl hydrazines with ethyl pyruvate gave the respective hydrazones 4-6; Fischer indolization led to substituted-1H-indole-2-carboxylic acid ethyl esters 7-9. The Mannich reaction of these compounds with formaldehyde and morpholine yielded ethyl 3-(morpholinomethyl)-substituted-1H-indole-2-carboxylates 10-12. The 5,7-dichloro-1H-indole-2-carbohydrazide 13 was cyclized with methyl orthoformate in DMF to give 6,8-dichloro[1,2,4]triazino[4,5-a]indol-1(2H)-one 14. Vilsmeier-Haack formylation of 7-9 gave ethyl 3-formyl-substituted-1H-indole-2carboxylates 15-17 whose 2,29-((5-chloro-2-(ethoxycarbonyl)-1H-indol-3-yl)methylene)bis-(sulfanediyl) diacetic acid 18 was prepared. The reaction of 15 and 16 with substituted anilines by conventional and microwave methods gave ethyl 3-(N-aryliminomethyl)-5-halo-1H-indole-2-carboxylates 19-29. In a cyclocondensation reaction of 19-25 with thiolactic acid or thioglycolic acid substituted indolylthiazolidinones 30-33 were prepared. Reaction of hydrazine hydrate with 15-17 did not give the respective hydrazones but directly led to the cyclized products substituted-3H-pyridazino[4,5-b]indol-4(5H)-ones 34-36, while a reaction with 2,4-dichlorophenylhydrazine yielded the uncyclized hydrazones. The chlorination of 35 and 36 with POCl 3 gave pyridazino[4,5-b]indoles 39 and 40, respectively; reaction of the latter compounds with morpholine gave 4-(substituted-5H-pyridazino[4,5-b]indol-4-yl)morpholine 41 and 42. Mannich reaction of 34 with formaldehyde and N-ethylpiperazine gave 8-chloro-3-((4-ethylpiperazin-1-yl)methyl)-3H-pyridazino[4,5-b]indol-4(5H)-one 43. The microwave assistance of selected reactions has a profound effect on the reaction speed. The structures of the new compounds were confirmed by both analytical and spectral data. Some compounds were subjected to investigations concerning their antimicrobial, tranquilizing, and anticonvulsant activities.
Nuclear Medicine and Biology, Jul 1, 2019
Journal of Organometallic Chemistry, Oct 1, 2012
The cationic complexes [Pd(h 3-C 3 H 5)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine)](X) (... more The cationic complexes [Pd(h 3-C 3 H 5)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine)](X) (2: X ¼ BF 4 À , 3: X ¼ ClO 4 À), and [Pd(h 3-2-CH 3-C 3 H 4)(2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)-pyridine)](BF 4 À) (4) have been synthesized by reacting the appropriate palladium-allyl precursor with 2-((4-propyl-1H-1,2,3-triazol-1-yl)methyl)pyridine in the presence of AgBF 4 or AgClO 4. The solid-state structure of 2 has been determined by single-crystal X-ray diffraction analysis. According to 1 H NMR spectroscopy the allyl protons undergo synesyn, antieanti exchange. 1 H NMR spectroscopy reveals that in acetone at temperatures lower than 223 K these complexes form aggregates the stability of which is attributed to solvophobic interactions. Complex 2 is an active catalyst for the SeM coupling of aryl bromides with phenylboronic acid; good reaction rates are obtained only with activated substrates, whereas with deactivated substrates catalyst decomposition to palladium black occurs.