Francesco Capitelli

A new dinuclear platinum complex with a nitrogen-containing geminal bisphosphonate as potential anticancer compound specifically targeted to bone tissues

The paper describes the synthesis and characterization of a new platinum dinuclear complex (2) bearing a nitrogen-containing geminal bisphosphonate (NBP, 1), structurally related to the commercial drug risedronate. NBPs themselves have shown in quite a few cases to be endowed with anticancer activity, therefore the new platinum complex has two potential antitumor moieties (the NBP ligand and the platinum residue) and could have high affinity for bone tumors or metastases (due to the presence of NBP). The free bisphosphonate (1) has been crystallized by a sol-gel method and characterized by X-ray diffraction analysis. The platinum complex (2) has been found to have a dinuclear structure with the bisphosphonate bridging two platinum moieties in a W conformation.

Two new ammonium diphosphates: crystal structure of Mn0.5NH4H2P2O7·H2O and MnNaNH4P2O7·3H2O

Abstract Two new ammonium diphosphates, Mn0.5NH4H2P2O7·H2O (1) and MnNaNH4P2O7·3H2O (2), have been synthesized and investigated by single crystal X-ray diffraction. Compound (1) crystallizes in the triclinic space group P1̅, and the unit cell dimensions are a = 7.0029(2) Å, b = 7.4401(2) Å, c = 7.8771(2) Å, α = 80.444(1)°, β = 71.359(1)°, γ = 87.408(1)°, V = 383.48(2) Å3, Z = 2; compound (2) crystallizes in the monoclinic space group Cc, with the following unit cell dimensions: a = 10.1124(4) Å, b = 16.4448(7) Å, c = 5.6000(3) Å, β = 104.304(2)°, V = 902.39(7) Å3, Z = 4. Final residuals are: R = 0.0281 and wR = 0.0769, by using 2356 reflections with I > 2σ(I), for (1); R = 0.0301 and wR = 0.0682, by using 2322 reflections with I > 2σ(I), for (2). The crystal packing of Mn0.5NH4H2P2O7·H2O consists of layers parallel to ac plane formed by MnO6 regular octahedra, H2P2O7 double tetrahedra and ammonium cations. Strong hydrogen bonds embed the dihydrogendiphosphate groups in the framework. The crystal packing of MnNaNH4P2O7·3H2O is made up of layers of P2O7 double tetrahedra, NaO7 monocapped octahedra and MnO6 regular octahedra down c. Water and ammonium cations molecules fill up the cavities between the above mentioned polyhedra. Strong hydrogen bonds complete the network.

Multi-methodological investigation of kunzite, hiddenite, alexandrite, elbaite and topaz, based on laser-induced breakdown spectroscopy and conventional analytical techniques for supporting mineralogical characterization

Gem-quality alexandrite, hiddenite and kunzite, elbaite and topaz minerals were characterized through a multi-methodological investigation based on EMPA-WDS, LA-ICP-MS, and laser-induced breakdown spectroscopy (LIBS). With respect to the others, the latter technique enables a simultaneous multi-elemental composition without any sample preparation and the detection of light elements, such as Li, Be and B. The criteria for the choice of minerals were: (a) the presence of chromophore elements in minor contents and/or as traces; (b) the presence of light lithophile elements (Li, Be and B); (c) different crystal chemistry complexity. The results show that LIBS can be employed in mineralogical studies for the identification and characterization of minerals, and as a fast screening method to determine the chemical composition, including the chromophore and light lithophile elements.

Crystal structure of new hexahydrate dicobalt pyrophosphate Co2P2O7·6H2O: comparison with Co2P2O72H2O, α-, β- and γ-Co2P2O7

Abstract A new dicobalt pyrophosphate, Co2P2O7·6H2O, has been synthesized and characterized by single crystal X-ray diffraction. The compound belongs to the mono clinic space group P21/n, and its unit cell dimensions are: a = 7.2077(2), b = 18.3373(5), c = 7.6762(2) Å, β = 92.4356(15)°, V = 1013.64(5) Å3, Z = 4. The structural parameters were refined to an R index of 0.0570 for 1937 reflections with I>2σ(Io). The framework of this pyro phosphate is made by the packing of layers of discrete CoO6 octahedra connected by double tetrahedra P2O7 groups. The (P2O7)4– anion group shows bent eclipsed conformation. A comparative study among anhydrous (α-, β- and γ-Co2P2O7) and hydrated forms (Co2P2O7·2H2O) of dicobalt pyrophosphates known in literature is presented.

Crystal-chemical investigation of Fe3(PO4)2· 8 H2O vivianite minerals

Abstract Crystal-chemistry of Fe3(PO4)2 · 8 H2O vivianite minerals was investigated by means of a multi-methodological approach based on electron microprobe analysis in wavelenght dispersive mode, single-crystal X-ray diffraction and infrared spectroscopy. To this aim, three specimens coming from Commentry (France) (1), Settefrati (Frosinone, Italy) (2) and Ibex Mine (Colorado, USA) (3), have been subject to EMPA analysis, indicating chemical composition (Fe2.94Mg0.06Mn0.01)Σ3.02(P1.99O8) · 8 H2O (1), (Fe2.96Mg0.01Mn0.04)Σ3.01((P1.96Si0.03Al0.02)Σ2.01O8) · 8 H2O (2) and (Fe2.65Zn0.27Mn0.06Na0.03Mg0.02)Σ3.03(P1.99O8) · 8 H2O (3); successively they have been subject to structural refinement by means of single-crystal X-ray diffraction within monoclinic space group C2/m, with the following unit cell constants: a = 10.100(3), b = 13.494(3), c = 4.709(3) Å; β = 104.24(4)° and V = 622.1(7) Å3 (1); a = 10.116(3); b = 13.473(3), c = 4.7064(7) Å; β = 104.33(4)° and V = 621.5(2) Å3 (2); a = 10.083(2), b = 13.468(2), c = 4.718(1) Å, β = 104.47(2)° and V = 620.3(2) Å3 (3). Iron cations occupy two special positions, making up single and dimerical octahedral groups, joined by (PO4) tetrahedra groups, in order to form infinite layers down b, making up, via consistent O—H … O hydrogen bonds, the three-dimensional framework. The present vivianite samples were subject to geochemical and crystal chemical comparisons, the latter also by means of bond valence analysis with literature available phases. Last, IR spectra were performed for the three phases, in order to provide information on bending and stretching modes of the minerals, as well as to investigate H bonds by means of Libowitzki formula application.

Self-assemblies of chiral p-haloaryl sulfoxides through C–H⋯O short contacts and halogen involving interactions

Single crystal X-ray structure determination of four crystals of alkyl or aryl p-haloaryl sulfoxides is reported. Intramolecular short contacts between the ortho-hydrogen of the aryl ring and the oxygen of the sulfinyl group were found to determine the conformations of the sulfoxides. On the other hand, in the absence of classical hydrogen bond donors, crystal packing arrangements are the results of intermolecular aryl hydrogen–oxygen short contacts and of interactions involving halogen atoms. From a comparison of the structures of the investigated sulfoxides with other literature data, the crystal packings of these types of compound appear to derive from a complex balance among different interactions.

Investigation on the weak interactions assembling the crystal structures of Betti bases

The crystal structures of (S, S)-aminobenzylnaphthols, easily produced by a chromatography-free highly stereoselective Betti reaction, were investigated by means of single crystal X-ray diffraction analysis, and the main intra- and intermolecular interactions were described. The presence of a strong intramolecular hydrogen bond was confirmed, whereas the whole crystal building was found to be due mainly to other bondings, such as CH⋯O and CH⋯π interactions. As far as the last interactions were concerned, we observed many short distances from one hydrogen atom to an aryl plane, together with the appropriate geometric requirements for the assemblies. The observations suggest that these interactions can play a relevant role in the crystal building. The absence of similar short distance CH⋯π interactions in the crystal of a diastereomeric (R, S)-aminobenzylnaphthol could be a suggestion of the preferential crystallisation of the (S, S)-stereoisomer and, consequently, its prevalence as a product of the Betti reaction.

Crystal structure and vibrational spectroscopy of the new acidic diphosphate (NH4)2Zn(H2P2O7)2 · 2 H2O

Abstract The hydrated ammonium hemizinc dihydrogen diphosphate (NH4)2Zn(H2P2O7)2 · 2 H2O was synthesized. It crystallizes in the triclinic system, space group P-1, Z = 1, with the following unit-cell-parameters: a = 7.0026(2) Å, b = 7.3297(2) Å, c = 7.7885(3) Å, α = 81.229(1)°, β = 71.064(1)°, γ = 88.172(1)°, V = 373.64(2) Å3. The structure was obtained by single-crystal X-ray diffractometry, and a full-matrix least-squares refinement based on F2 gave a final R1 index of = 0.0447 (wR2 = 0.1336), utilizing 2055 observed reflections with I > 2σ(I). The crystal packing consists in a three-dimensional network made by layers parallel to ab plane of ZnO6 octahedra sharing four vertices with H2P2O7 double tetrahedra: (NH4)+ cations fill up the cavities between tetrahedra and octahedra; strong hydrogen bonds stabilize the framework. The dihydrogendiphosphate anion (H2P2O7)2- shows bent eclipsed conformation and the Zn2+ ion lies on inversion centre. Raman and infrared spectra of (NH4)2Zn(H2P2O7)2 · 2 H2O have been collected and interpreted using factor group analysis. No coincidences observed between most of Raman and IR spectral bands confirmed the centrosymmetric structure of the title compound; the vibrational spectra point to a bent POP bridge angle.

Crystal-chemical and structural characterization of fluorapatites in ejecta from Somma-Vesuvius volcanic complex

Abstract The mineralogy and crystal chemistry of apatites occurring in 14 ejecta of historical eruptions (1631 and 1872 A.D.) of the Somma-Vesuvius volcanic complex were investigated by a multi-methodological approach including polarized optical microscopy, scanning electron microscope, electron microprobe analysis in wavelength-dispersive mode, laser ablation inductively coupled plasma mass spectroscopy, and single-crystal X‑ray diffraction. Five different groups of apatite, with different mineralogical and crystal-chemical features, were identified. Apatite crystals occur with well-developed hexagonal prismatic habit and, more rarely, with skeletal acicular forms. The crystals are yellow (type 1), transparent and colorless (type 2 and type 3), green (type 4) and aquamarine colored (type 5), with different paragenesis: macro-crystalline aggregates of clinopyroxenes, phlogopite, and apatite (type 1; type 4); clusters of apatite with micro-crystalline clinopyroxene, minerals of the cancrinite group, feldspars, and opaque minerals (type 2); aggregates of apatite, sellaite, wagnerite, gypsum, and phlogopite (type 3); aggregates of davyne, nepheline, mica group minerals, and apatite (type 5). Chemical analyses of apatites show variable amounts of Na, REE, Mg, Sr, and Fe replacing Ca, not negligible amounts of Si and S substituting P, and a significant substitution of Cl and OH instead of F. Five crystals representative of each apatite-type were studied by single-crystal X‑ray diffraction. Their crystal structure was refined in the hexagonal P63/m space group. A significant variation of the unit-cell parameters with the composition was observed. A comparative crystal-chemical analysis between apatites from Somma-Vesuvius and those from other localities is carried out.

New hybrid diphosphates Ln2(NH2(CH2)2NH2)(HP2O7)2 · 4 H2O(Ln = Eu, Tb, Er): synthesis, single crystal and powder X-ray crystal structure

Crystals of lanthanide ethylenediamine diphos phates Ln2(NH2(CH2)2NH2)(HP2O7)2 · 4 H2O (Ln = Eu (1), Tb (2), Er (2)) have been synthesized and investigated by single crystal X-ray diffractometry (Eu and Tb phases) and by powder X-ray diffractometry (Er phase). The three structures resulted to be isostructural within triclinic space group P-1, with unit cell parameters of a = 6.5050(6) Å; b = 6.9990(2) Å; c = 9.8450(9) Å; α = 81.548(5)°; β = 80.631(19)°; γ = 88.369(9)°; V = 437.44(6) Å3(1), a = 6.4360(7) Å; b = 6.9480(12) Å; c = 9.816(4) Å; α = 81.987(19)°; β = 80.595(16)°; γ = 88.591(13)°; V = 428.82(19) Å3(2), a = 6.39658(2) Å; b = 6.86682(2) Å; c = 9.78849(3) Å; α = 81.6811(4)°; β = 80.2304(3)°; γ = 88.3812(3)°; V = 419.255(3) Å3(3).The three-dimensional network is built up by the repetition of ab-parallel layers of LnO8 polyhedra corner-sharing with (HP2O7) groups; ethylenediamine molecules lie between such layers, acting both as receptors and donors in strong hydrogen bonds which assure the stabilizing of the entire framework.