Chiara Massera | Università degli Studi di Parma (original) (raw)
Papers by Chiara Massera
Supramolecular Chemistry, 2014
ABSTRACT In this paper, we report the first example of a tetramethylene bridged cavitand with two... more ABSTRACT In this paper, we report the first example of a tetramethylene bridged cavitand with two distal methylbenzoate legs at the lower rim, adopting a unique and unprecedented equatorial equatorial (ee) configuration both in solution and in the solid state, as confirmed by NMR and single crystal X-ray diffraction. The presence of functional groups, which are potential metal binding sites in the ee configuration, makes these cavitands suitable candidates to be used as pillars in metal-organic frameworks (MOF) as specific molecular recognition units.
Inorganic Chemistry, 2006
The reaction of Zn(NO 3) 2 ‚6H 2 O or Cu(NO 3) 2 ‚3H 2 O with the star-shaped ligand 2,4,6-tris(d... more The reaction of Zn(NO 3) 2 ‚6H 2 O or Cu(NO 3) 2 ‚3H 2 O with the star-shaped ligand 2,4,6-tris(di-2-picolylamino)[1,3,5]triazine (dipicatriz) in acetonitrile results in the formation of the mono-or trinuclear coordination compounds [Zn-(dipicatriz)(NO 3) 2 ] (1), [Zn 3 (dipicatriz)(NO 3) 6 ](CH 3 CN) 3 (2), and [Cu 3 (dipicatriz)(NO 3) 2 (H 2 O) 6 ](NO 3) 4 (3), depending on the metal-to-ligand ratios used during the crystallization process. Their crystal structures exhibit unique supramolecular interactions. Compounds 1 and 2 show anion−π interactions between coordinated nitrate ions and the s-triazine ring. Compound 3 exhibits remarkable interactions between two noncoordinated nitrate anions and the two faces of the electron-deficient heteroaromatic ring, corroborating earlier theoretical investigations in this area. New theoretical investigations have been carried out on nitrate−π interactions, taking into account the particular position of the anion toward the aromatic ring observed in the crystal structures.
Chemistry-a European Journal, 2008
M olecular recognition is a recurrent theme in chemical sensing because of the importance of sele... more M olecular recognition is a recurrent theme in chemical sensing because of the importance of selectivity for sensor performances. The popularity of molecular recognition in chemical sensing has resulted from the progress made in mastering weak interactions, which has enabled the design of synthetic receptors according to the analyte to be detected.
New Journal of Chemistry, 2006
... Crystallographic evidence of theoretically novel anionπ interactions. Hélène Casellas, Chiar... more ... Crystallographic evidence of theoretically novel anionπ interactions. Hélène Casellas, Chiara Massera, Francesco Buda, Patrick Gamez and Jan Reedijk New J. Chem., 2006, 30, 1561-1566. DOI: 10.1039/B608172J , Paper. ...
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Inorganic Chemistry, 2008
The reactions of the ligand 2-(2-pyridyl)benzthiazole (pbt) with CuBr 2 and ZnCl 2 in acetonitril... more The reactions of the ligand 2-(2-pyridyl)benzthiazole (pbt) with CuBr 2 and ZnCl 2 in acetonitrile produce the complexes [Cu(pbt)Br 2] ( 1) and [Zn(pbt)Cl 2] ( 3), respectively. When complex 1 is dissolved in DMF, complex 2 is obtained as light-green crystals. The reaction of pbt with CuBr 2 in DMF also yields the complex [Cu(pbt)Br 2(dmf)] ( 2) (dmf = dimethylformamide). Complexes 1- 3 were characterized by X-ray crystallography. Complexes 1 and 3 have distorted tetrahedral coordination environments, and complex 2 is constituted of two slightly different copper centers, both exhibiting distorted trigonal bipyramidal geometries. Complexes 1 and 2 cleave phiX174 phage DNA, both in the presence and the absence of reductant. The free ligand pbt does not show any DNA-cleaving abilities. The poor solubility of complex 3 makes it not applicable for biological tests. The occurrence of DNA breaks in the presence of various radical scavengers suggests that no diffusible radicals are involved in the DNA cleavage by complex 1, as none of the scavengers inhibit the cleavage reaction. The DNA-cleavage products are not religated with the enzyme T4 DNA ligase, which is an additional proof that the cleavage is nonhydrolytic. Most probably the cleaving reaction involves reactive oxygen species, which could not be trapped, leading to an oxidative mechanism. An easy oxidation of Cu (II)(pbt)Br 2 to Cu (III) in DMF and the reduction of the same to Cu (I), under similar electrochemical conditions may lead to the in situ activation of molecular oxygen, resulting in the formation of metal solvated nondiffusible radicals able to prompt the oxidative cleavage of DNA. Complex 1 and the pure ligand exhibit remarkable cytotoxic effects against the cancer cell lines L1210 and A2780 and also against the corresponding cisplatin-resistant mutants of these cell lines.
![Research paper thumbnail of Biomimetic macrocyclic receptors for carboxylate anion recognition based on C-linked peptidocalix[4]arenes](https://attachments.academia-assets.com/44805181/thumbnails/1.jpg)
](Proceedings of the National Academy of Sciences, 2002
Four ionic fullerene derivatives, which are relatively soluble in polar solvents, are shown to or... more Four ionic fullerene derivatives, which are relatively soluble in polar solvents, are shown to organize into morphologically different nanoscale structures. Spheres, nanorods, and nanotubules form in water depending on the side chain appendage of the fullerene spheroid. Images at different nanoscale structures were obtained via transmission electron microscopy. Also, computer simulations were used for investigating the relative spatial arrangements. The efficient method to fabricate almost perfect and uniformly shaped nanotubular crystals, which order spontaneously by self-assembly, opens the way to the possibility of exploiting the fullerene properties at the nanometer scale.
Acta Crystallographica Section A Foundations of Crystallography, 2010
Tetrahedron Letters, 2014
ABSTRACT The novel method allows the carbonylative cyclization of allylamines in the absence of a... more ABSTRACT The novel method allows the carbonylative cyclization of allylamines in the absence of any metal or base catalyst.
Molecules, 2015
The present work reports the synthesis and complexation properties of five mixed bridge P=O/P=S c... more The present work reports the synthesis and complexation properties of five mixed bridge P=O/P=S cavitands toward N,N-methyl butyl ammonium chloride (1) as prototype guest. The influence of number and position of P=O and P=S groups on the affinity of phosphonate cavitands toward 1 is assessed via ITC titrations in DCE as solvent. Comparison of the resulting Kass values, the enthalpic and entropic contributions to the overall binding with those of the parent tetraphosphonate Tiiii and tetrathiophosphonate TSiiii cavitands allows one to single out the simultaneous dual H-bond between the cavitand and the salt as the major player in complexation.
![Research paper thumbnail of A novel self-assembled supramolecular architecture involving cation, anion and a calix[4]arene heteroditopic receptor](https://attachments.academia-assets.com/39187281/thumbnails/1.jpg)
](Tetrahedron Letters, 2002
In the presence of potassium acetate the heteroditopic calix[4]arene receptor 1, in the 1,3-alter... more In the presence of potassium acetate the heteroditopic calix[4]arene receptor 1, in the 1,3-alternate structure and bearing two pentafluorophenyl amide groups as anion binders and a crown-5 polyether for cation complexation, self-assembles in an unexpected 2:2:2 (calixarene:cation:anion) supramolecular structure, as shown by X-ray crystal structure.
Proceedings of the National Academy of Sciences, 2002
Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the follow... more Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the following features: (i) new motifs for alkali metal ion complexation (i.e., cationic receptors for cations), (ii) a new family of triaza-metalloligands, and (iii) a double box-like cage. The cages are synthesized by the condensation of [CpCo(CN) 3] ؊ and [Cp*Ru(NCMe)3] ؉ (cyclopentadienyl, Cp; pentamethylcyclopentadienyl, Cp*) the presence of Cs ؉ . The species {Csʲ{[CpCo(CN) 3]4[Cp*Ru]4} ؉ and {Csʲ{[CpCo(CN)3] 4[Cp*Ru]3[Cp*Rh]} 2؉ illustrate the box-completion reaction Cs ʲ Co 4Ru3 ؉ M (M ؍ Cp*Rh 2؉ , Cp*Ru ؉ ). With the naked ion precursors [Na(NCMe) 6] ؉ and [Fe(NCMe)6
Polyhedron, 2005
2 AE 5H 2 O. The complex contains tetranuclear building blocks, and very interestingly, three of ... more 2 AE 5H 2 O. The complex contains tetranuclear building blocks, and very interestingly, three of the four imidazole rings coordinated to Cu1 and Cu2 are dehydronated. Nevertheless, all the imidazolate rings are coordinated to Cu in a monodentate mode, although each dehydronated N is strongly hydrogen bonded to a lattice water molecule. The Cu-Cu distances between the copper(II) atoms in the tetranuclear units vary from 5.843 to 6.013 Å . The polynuclear complex, based on chloro-bridged Cu(II) pairs, is further stabilized by stacking interaction between imidazolate moieties and by a network of intermolecular hydrogen bonds. The differences between the ligand-field spectrum and the UV-Vis spectrum of the complex in MeOH indicate that the complex may partially dissociate in MeOH, as also evidenced by ESI-MS. The X-band EPR spectrum of the polycrystalline powder of the complex shows fairly broad isotropic signal centered at a g = 2.11, and EPR study in the MeOH solution at 77 K shows two group of signals due to [Cu(MeOH) 6 ] 2+ cation and the mononuclear species from the dissociated polynuclear compound. A weak antiferromagnetic interaction in dichloro-bridged Cu(II) pair dominates the magnetic behaviour of the compound.
The Journal of Organic Chemistry, 2004
Ring closure reactions O 0130 Synthesis of 4H-3,1-Benzoxazines, Quinazolin-2-ones, and Quinoline-... more Ring closure reactions O 0130 Synthesis of 4H-3,1-Benzoxazines, Quinazolin-2-ones, and Quinoline-4-ones by Palladium-Catalyzed Oxidative Carbonylation of 2-Ethynylaniline Derivatives. -(COSTA*, M.; DELLA CA, N.; GABRIELE, B.; MASSERA, C.; SALERNO, G.; SOLIANI, M.; J.
The Journal of Organic Chemistry, 2006
The self-assembly between bidentate cavitand ligands and mono/dinuclear metal precursors to give ... more The self-assembly between bidentate cavitand ligands and mono/dinuclear metal precursors to give cavitand frameworks has been explored. For this purpose, two new cavitands bearing AB and AC phenylpyridyl moieties at the upper rim have been synthesized. A series of self-assembled molecular dimers featuring fac-Re(CO)(3)Br as metal corners have been prepared and characterized. Two possible dimeric structures (C-shaped and S-shaped) are possible when AB cavitand 2 is used in the self-assembly reaction; only one is obtained in the case of AC cavitand 3. In addition, the self-assembly of AB-dibridged cavitand 2 with dinuclear Pd/Pt metal precursors 5a and 5b has been studied. At this level of complexity, the self-assembly can lead to more than one structure. Several different final structures have been envisioned and their formation analyzed in silico and in solution. Out of the three possible cyclic structures (dimer, trimer, and tetramer), only the entropically favored dimer 6a (6b) is formed, as predicted from molecular modeling and demonstrated by PGSE NMR experiments.
![Research paper thumbnail of [Cu(phdpa)Cl]+ (phdpa=bis(2-pyridylmethyl)aniline): a moiety of unusual stability in some 1:1 Cu(II) complexes of phdpa. Synthesis and X-ray crystal structures of [Cu(phdpa)Cl2] and [Cu2(phdpa)2Cl3]PF6·0.5MeOH](https://attachments.academia-assets.com/39187280/thumbnails/1.jpg)
](Inorganica Chimica Acta, 2002
1:1 copper(II) complexes of bis(dipyridylmethyl)aniline (phdpa) of various kinds, with chloride a... more 1:1 copper(II) complexes of bis(dipyridylmethyl)aniline (phdpa) of various kinds, with chloride and PF 6 ( as anions, were synthesized and characterized by elemental analysis, IR spectroscopy and X-ray structure crystallography. The crystal structures of [Cu(phdpa)Cl 2 ] (I) and [Cu 2 (phdpa) 2 Cl 3 ]PF 6 ×/0.5MeOH (II) showed that the metal atoms are five-coordinated and that the structures are also stabilized by a triple intramolecular hydrogen-bond system. The resulting unusual stability of the [Cu(phdpa)Cl] ' moiety influences the exchange properties with PF 6 ( of compound I, which gave complexes where the cationic group is maintained also under drastic reaction conditions. #
Inorganica Chimica Acta, 2001
Some ternary Cu(dipyam)(OOCR)(OR) complexes (dipyam = 2,2%-dipyridylamine; RCOO − = acetate, benz... more Some ternary Cu(dipyam)(OOCR)(OR) complexes (dipyam = 2,2%-dipyridylamine; RCOO − = acetate, benzoate, cmb (2-chloro-5-methylthio-benzoate), mta (methylthioacetate), mtn (2-methylthio-nicotinate); OR − = pnp (p-nitrophenolate), dcp (2,6dichlorophenolate), tcp (2,4,6-trichlorophenolate)) have been synthesized. Their IR spectra are included and the X-ray diffraction structure is given for the crystals of
European Journal of Organic Chemistry, 2001
Four new cavitand ligands, modified at the lower rim with cyano and pyridyl functional groups, ha... more Four new cavitand ligands, modified at the lower rim with cyano and pyridyl functional groups, have been synthesized and their coordinative behaviour toward transition metal ions has been explored. The outcome of the self-assembly of these compounds in the ...
European Journal of Inorganic Chemistry, 2004
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![Research paper thumbnail of Coordination Dependence of Magnetic Properties within a Family of Related [FeII2] Complexes of a Triazine-Based Ligand](https://attachments.academia-assets.com/39187275/thumbnails/1.jpg)
](European Journal of Inorganic Chemistry, 2006
The coordination chemistry of the polydentate ligand 2,4,6tris(dipyridin-2-ylamino)-1,3,5-triazin... more The coordination chemistry of the polydentate ligand 2,4,6tris(dipyridin-2-ylamino)-1,3,5-triazine (dpyatriz) with Fe II has been explored, leading through variation of the counterion and the solvent system to the preparation of three different dinuclear complexes: [Fe 2 (dpyatriz) 2 (H 2 O) 2 (CH 3 CN) 2 ]-(ClO 4 ) 4 (1), [Fe 2 (dpyatriz) 2 (H 2 O) 2 (CH 3 OH) 2 ](BF 4 ) 4 (2) and [Fe 2 (dpyatriz) 2 Cl 2 ](CF 3 SO 3 ) 2 (3). The X-ray structure of these compounds has revealed that besides the difference in the noncoordinated anion, complex 1 differs from complex 2 only in the nature of the terminal ligands. Bulk magnetisation studies and Mössbauer spectroscopy have shown that such a subtle difference produces a change to the crystal field on the metal atoms, originating an important disparity of the magnetic behaviour. Thus, complex 1 experiences a partial spin crossover centred at approximately 265 K, whereas com-
European Journal of Inorganic Chemistry, 2004
Supramolecular Chemistry, 2014
ABSTRACT In this paper, we report the first example of a tetramethylene bridged cavitand with two... more ABSTRACT In this paper, we report the first example of a tetramethylene bridged cavitand with two distal methylbenzoate legs at the lower rim, adopting a unique and unprecedented equatorial equatorial (ee) configuration both in solution and in the solid state, as confirmed by NMR and single crystal X-ray diffraction. The presence of functional groups, which are potential metal binding sites in the ee configuration, makes these cavitands suitable candidates to be used as pillars in metal-organic frameworks (MOF) as specific molecular recognition units.
Inorganic Chemistry, 2006
The reaction of Zn(NO 3) 2 ‚6H 2 O or Cu(NO 3) 2 ‚3H 2 O with the star-shaped ligand 2,4,6-tris(d... more The reaction of Zn(NO 3) 2 ‚6H 2 O or Cu(NO 3) 2 ‚3H 2 O with the star-shaped ligand 2,4,6-tris(di-2-picolylamino)[1,3,5]triazine (dipicatriz) in acetonitrile results in the formation of the mono-or trinuclear coordination compounds [Zn-(dipicatriz)(NO 3) 2 ] (1), [Zn 3 (dipicatriz)(NO 3) 6 ](CH 3 CN) 3 (2), and [Cu 3 (dipicatriz)(NO 3) 2 (H 2 O) 6 ](NO 3) 4 (3), depending on the metal-to-ligand ratios used during the crystallization process. Their crystal structures exhibit unique supramolecular interactions. Compounds 1 and 2 show anion−π interactions between coordinated nitrate ions and the s-triazine ring. Compound 3 exhibits remarkable interactions between two noncoordinated nitrate anions and the two faces of the electron-deficient heteroaromatic ring, corroborating earlier theoretical investigations in this area. New theoretical investigations have been carried out on nitrate−π interactions, taking into account the particular position of the anion toward the aromatic ring observed in the crystal structures.
Chemistry-a European Journal, 2008
M olecular recognition is a recurrent theme in chemical sensing because of the importance of sele... more M olecular recognition is a recurrent theme in chemical sensing because of the importance of selectivity for sensor performances. The popularity of molecular recognition in chemical sensing has resulted from the progress made in mastering weak interactions, which has enabled the design of synthetic receptors according to the analyte to be detected.
New Journal of Chemistry, 2006
... Crystallographic evidence of theoretically novel anionπ interactions. Hélène Casellas, Chiar... more ... Crystallographic evidence of theoretically novel anionπ interactions. Hélène Casellas, Chiara Massera, Francesco Buda, Patrick Gamez and Jan Reedijk New J. Chem., 2006, 30, 1561-1566. DOI: 10.1039/B608172J , Paper. ...
[
Inorganic Chemistry, 2008
The reactions of the ligand 2-(2-pyridyl)benzthiazole (pbt) with CuBr 2 and ZnCl 2 in acetonitril... more The reactions of the ligand 2-(2-pyridyl)benzthiazole (pbt) with CuBr 2 and ZnCl 2 in acetonitrile produce the complexes [Cu(pbt)Br 2] ( 1) and [Zn(pbt)Cl 2] ( 3), respectively. When complex 1 is dissolved in DMF, complex 2 is obtained as light-green crystals. The reaction of pbt with CuBr 2 in DMF also yields the complex [Cu(pbt)Br 2(dmf)] ( 2) (dmf = dimethylformamide). Complexes 1- 3 were characterized by X-ray crystallography. Complexes 1 and 3 have distorted tetrahedral coordination environments, and complex 2 is constituted of two slightly different copper centers, both exhibiting distorted trigonal bipyramidal geometries. Complexes 1 and 2 cleave phiX174 phage DNA, both in the presence and the absence of reductant. The free ligand pbt does not show any DNA-cleaving abilities. The poor solubility of complex 3 makes it not applicable for biological tests. The occurrence of DNA breaks in the presence of various radical scavengers suggests that no diffusible radicals are involved in the DNA cleavage by complex 1, as none of the scavengers inhibit the cleavage reaction. The DNA-cleavage products are not religated with the enzyme T4 DNA ligase, which is an additional proof that the cleavage is nonhydrolytic. Most probably the cleaving reaction involves reactive oxygen species, which could not be trapped, leading to an oxidative mechanism. An easy oxidation of Cu (II)(pbt)Br 2 to Cu (III) in DMF and the reduction of the same to Cu (I), under similar electrochemical conditions may lead to the in situ activation of molecular oxygen, resulting in the formation of metal solvated nondiffusible radicals able to prompt the oxidative cleavage of DNA. Complex 1 and the pure ligand exhibit remarkable cytotoxic effects against the cancer cell lines L1210 and A2780 and also against the corresponding cisplatin-resistant mutants of these cell lines.
Proceedings of the National Academy of Sciences, 2002
Four ionic fullerene derivatives, which are relatively soluble in polar solvents, are shown to or... more Four ionic fullerene derivatives, which are relatively soluble in polar solvents, are shown to organize into morphologically different nanoscale structures. Spheres, nanorods, and nanotubules form in water depending on the side chain appendage of the fullerene spheroid. Images at different nanoscale structures were obtained via transmission electron microscopy. Also, computer simulations were used for investigating the relative spatial arrangements. The efficient method to fabricate almost perfect and uniformly shaped nanotubular crystals, which order spontaneously by self-assembly, opens the way to the possibility of exploiting the fullerene properties at the nanometer scale.
Acta Crystallographica Section A Foundations of Crystallography, 2010
Tetrahedron Letters, 2014
ABSTRACT The novel method allows the carbonylative cyclization of allylamines in the absence of a... more ABSTRACT The novel method allows the carbonylative cyclization of allylamines in the absence of any metal or base catalyst.
Molecules, 2015
The present work reports the synthesis and complexation properties of five mixed bridge P=O/P=S c... more The present work reports the synthesis and complexation properties of five mixed bridge P=O/P=S cavitands toward N,N-methyl butyl ammonium chloride (1) as prototype guest. The influence of number and position of P=O and P=S groups on the affinity of phosphonate cavitands toward 1 is assessed via ITC titrations in DCE as solvent. Comparison of the resulting Kass values, the enthalpic and entropic contributions to the overall binding with those of the parent tetraphosphonate Tiiii and tetrathiophosphonate TSiiii cavitands allows one to single out the simultaneous dual H-bond between the cavitand and the salt as the major player in complexation.
Tetrahedron Letters, 2002
In the presence of potassium acetate the heteroditopic calix[4]arene receptor 1, in the 1,3-alter... more In the presence of potassium acetate the heteroditopic calix[4]arene receptor 1, in the 1,3-alternate structure and bearing two pentafluorophenyl amide groups as anion binders and a crown-5 polyether for cation complexation, self-assembles in an unexpected 2:2:2 (calixarene:cation:anion) supramolecular structure, as shown by X-ray crystal structure.
Proceedings of the National Academy of Sciences, 2002
Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the follow... more Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the following features: (i) new motifs for alkali metal ion complexation (i.e., cationic receptors for cations), (ii) a new family of triaza-metalloligands, and (iii) a double box-like cage. The cages are synthesized by the condensation of [CpCo(CN) 3] ؊ and [Cp*Ru(NCMe)3] ؉ (cyclopentadienyl, Cp; pentamethylcyclopentadienyl, Cp*) the presence of Cs ؉ . The species {Csʲ{[CpCo(CN) 3]4[Cp*Ru]4} ؉ and {Csʲ{[CpCo(CN)3] 4[Cp*Ru]3[Cp*Rh]} 2؉ illustrate the box-completion reaction Cs ʲ Co 4Ru3 ؉ M (M ؍ Cp*Rh 2؉ , Cp*Ru ؉ ). With the naked ion precursors [Na(NCMe) 6] ؉ and [Fe(NCMe)6
Polyhedron, 2005
2 AE 5H 2 O. The complex contains tetranuclear building blocks, and very interestingly, three of ... more 2 AE 5H 2 O. The complex contains tetranuclear building blocks, and very interestingly, three of the four imidazole rings coordinated to Cu1 and Cu2 are dehydronated. Nevertheless, all the imidazolate rings are coordinated to Cu in a monodentate mode, although each dehydronated N is strongly hydrogen bonded to a lattice water molecule. The Cu-Cu distances between the copper(II) atoms in the tetranuclear units vary from 5.843 to 6.013 Å . The polynuclear complex, based on chloro-bridged Cu(II) pairs, is further stabilized by stacking interaction between imidazolate moieties and by a network of intermolecular hydrogen bonds. The differences between the ligand-field spectrum and the UV-Vis spectrum of the complex in MeOH indicate that the complex may partially dissociate in MeOH, as also evidenced by ESI-MS. The X-band EPR spectrum of the polycrystalline powder of the complex shows fairly broad isotropic signal centered at a g = 2.11, and EPR study in the MeOH solution at 77 K shows two group of signals due to [Cu(MeOH) 6 ] 2+ cation and the mononuclear species from the dissociated polynuclear compound. A weak antiferromagnetic interaction in dichloro-bridged Cu(II) pair dominates the magnetic behaviour of the compound.
The Journal of Organic Chemistry, 2004
Ring closure reactions O 0130 Synthesis of 4H-3,1-Benzoxazines, Quinazolin-2-ones, and Quinoline-... more Ring closure reactions O 0130 Synthesis of 4H-3,1-Benzoxazines, Quinazolin-2-ones, and Quinoline-4-ones by Palladium-Catalyzed Oxidative Carbonylation of 2-Ethynylaniline Derivatives. -(COSTA*, M.; DELLA CA, N.; GABRIELE, B.; MASSERA, C.; SALERNO, G.; SOLIANI, M.; J.
The Journal of Organic Chemistry, 2006
The self-assembly between bidentate cavitand ligands and mono/dinuclear metal precursors to give ... more The self-assembly between bidentate cavitand ligands and mono/dinuclear metal precursors to give cavitand frameworks has been explored. For this purpose, two new cavitands bearing AB and AC phenylpyridyl moieties at the upper rim have been synthesized. A series of self-assembled molecular dimers featuring fac-Re(CO)(3)Br as metal corners have been prepared and characterized. Two possible dimeric structures (C-shaped and S-shaped) are possible when AB cavitand 2 is used in the self-assembly reaction; only one is obtained in the case of AC cavitand 3. In addition, the self-assembly of AB-dibridged cavitand 2 with dinuclear Pd/Pt metal precursors 5a and 5b has been studied. At this level of complexity, the self-assembly can lead to more than one structure. Several different final structures have been envisioned and their formation analyzed in silico and in solution. Out of the three possible cyclic structures (dimer, trimer, and tetramer), only the entropically favored dimer 6a (6b) is formed, as predicted from molecular modeling and demonstrated by PGSE NMR experiments.
Inorganica Chimica Acta, 2002
1:1 copper(II) complexes of bis(dipyridylmethyl)aniline (phdpa) of various kinds, with chloride a... more 1:1 copper(II) complexes of bis(dipyridylmethyl)aniline (phdpa) of various kinds, with chloride and PF 6 ( as anions, were synthesized and characterized by elemental analysis, IR spectroscopy and X-ray structure crystallography. The crystal structures of [Cu(phdpa)Cl 2 ] (I) and [Cu 2 (phdpa) 2 Cl 3 ]PF 6 ×/0.5MeOH (II) showed that the metal atoms are five-coordinated and that the structures are also stabilized by a triple intramolecular hydrogen-bond system. The resulting unusual stability of the [Cu(phdpa)Cl] ' moiety influences the exchange properties with PF 6 ( of compound I, which gave complexes where the cationic group is maintained also under drastic reaction conditions. #
Inorganica Chimica Acta, 2001
Some ternary Cu(dipyam)(OOCR)(OR) complexes (dipyam = 2,2%-dipyridylamine; RCOO − = acetate, benz... more Some ternary Cu(dipyam)(OOCR)(OR) complexes (dipyam = 2,2%-dipyridylamine; RCOO − = acetate, benzoate, cmb (2-chloro-5-methylthio-benzoate), mta (methylthioacetate), mtn (2-methylthio-nicotinate); OR − = pnp (p-nitrophenolate), dcp (2,6dichlorophenolate), tcp (2,4,6-trichlorophenolate)) have been synthesized. Their IR spectra are included and the X-ray diffraction structure is given for the crystals of
European Journal of Organic Chemistry, 2001
Four new cavitand ligands, modified at the lower rim with cyano and pyridyl functional groups, ha... more Four new cavitand ligands, modified at the lower rim with cyano and pyridyl functional groups, have been synthesized and their coordinative behaviour toward transition metal ions has been explored. The outcome of the self-assembly of these compounds in the ...
European Journal of Inorganic Chemistry, 2004
Skip to Main Content. ...
European Journal of Inorganic Chemistry, 2006
The coordination chemistry of the polydentate ligand 2,4,6tris(dipyridin-2-ylamino)-1,3,5-triazin... more The coordination chemistry of the polydentate ligand 2,4,6tris(dipyridin-2-ylamino)-1,3,5-triazine (dpyatriz) with Fe II has been explored, leading through variation of the counterion and the solvent system to the preparation of three different dinuclear complexes: [Fe 2 (dpyatriz) 2 (H 2 O) 2 (CH 3 CN) 2 ]-(ClO 4 ) 4 (1), [Fe 2 (dpyatriz) 2 (H 2 O) 2 (CH 3 OH) 2 ](BF 4 ) 4 (2) and [Fe 2 (dpyatriz) 2 Cl 2 ](CF 3 SO 3 ) 2 (3). The X-ray structure of these compounds has revealed that besides the difference in the noncoordinated anion, complex 1 differs from complex 2 only in the nature of the terminal ligands. Bulk magnetisation studies and Mössbauer spectroscopy have shown that such a subtle difference produces a change to the crystal field on the metal atoms, originating an important disparity of the magnetic behaviour. Thus, complex 1 experiences a partial spin crossover centred at approximately 265 K, whereas com-
European Journal of Inorganic Chemistry, 2004