Rhenium(III) and technetium(III) complexes with 2-mercapto-1,3-azole ligands and X-ray crystal structures

Reactions of labile [MCl3(PPh3)2(NCMe)] (M = Tc, Re) precursors with 1H-benzoimidazole-2-thiol (H2L1), 5-methyl-1H-benzoimidazole-2-thiol (H2L2) and 1H-imidazole-2-thiol (H2L3), in the presence of PPh3 and [AsPh4]Cl gave a new series of trigonal bipyramidal M(III) complexes [AsPh4]{[M(PPh3)Cl(H2L1–3)3]Cl3} (M = Re, 1–3;M = Tc, 4–6). The molecular structures of 1 and 3 were determined by X-ray diffraction. When the reactions were carried out with benzothiazole-2-thiol (HL4) and benzoxazole-2-thiol (HL5), neutral paramagnetic monosubstituted M(III) complexes [M(PPh3)2Cl2(L4,5)] (M = Re, 8, 9; M = Tc, 10, 11) were obtained. In these compounds, the central metal ions adopt an octahedral coordination geometry as authenticated by single crystal X-ray diffraction analysis of 8 and 11. Rhenium and technetium complexes 1, 4 and rhenium chelate compounds 8, 9 have been also synthesized by reduction of [MO4] with PPh3 and HCl in the presence of the appropriate ligand. All the complexes were characterized by elemental analyses, FTIR and NMR spectroscopy

Unprecedent solar photoextrusion of molecular hydrogen fron octahedral ruthenium (II) dihydrides: un easy acces to ortho-metalated species.

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Reactivity of [M=O] (3+) (M = Tc, Re) core towards 2-mercapto-1,3-azole ligands. Formation of a new organometallic complex of Re(IV) and X-ray crystal structures

Imidazole-2-thiol derivatives H2L1–3 (H2L1 = 1H-benzoimidazole-2-thiol, H2L2 = 5-methyl-1H-benzoimidazole-2-thiol, and H2L3 = 1H-imidazole-2-thiol) act as neutral monodentate ligands in a number of technetium and rhenium complexes. Disubstituted M(V) (M = Tc, Re) complexes of the type [AsPh4]{[MOCl2(H2Ln)2(H2O)]Cl2} are formed when [MOCl4] react with H2L1–3 in 1:2 stoichiometric ratio. Single crystal X-ray structure determinations were carried out on [AsPh4]{[TcOCl2(H2L1)2(H2O)]Cl2}. The coordination sphere is pseudo-octahedral in which the sulfur atoms of two ligands sit in the equatorial plane and a water molecule is in trans to the TcO multiple bond. All the complexes react with an excess of the corresponding ligand to form tetrasubstituted cationic species {[MO(H2Ln)4]Cl3}. These complexes can be also isolated by reaction of [MOCl4] with an excess of ligand. No complex is obtained with benzothiazole-2-thiol (HL4) and benzoxazole-2-thiol (HL5). Ligand exchange reactions of [ReOCl3(PPh3)2] with HL4,5 have also been investigated. Treating the oxo-precursor with HL4 no product is isolated, while with HL5 the chelate oxo-compound [ReOCl2(L5)(PPh3)] is formed as two isomers. An interesting organometallic complex of Re(IV) [ReCl3(L5*)(PPh3)2] is obtained when a slight excess of HL5 reacts with [ReOCl3(PPh3)2] in refluxing benzene solution and in air. Geometry about the Re atom is approximately octahedral in which the equatorial plane contains three Cl atoms and the carbon atom of the benzoxazole ligand anion, the apical positions are occupied by two PPh3. The reaction with O-ethyl S-hydrogen p-tolyl carbonothioimidate HL6 which contains the same heteroatoms of HL5 does not form an organometallic species, but forms the chelate oxo-Re(V) complex [ReOCl2(L6)(PPh3)]. The solid-state structure has been authenticated by X-ray crystallography

EVALUATION OF A NEW NANO-COATING ON IMPLANT OSSEOINTEGRATION: A HISTOLOGICAL STUDY IN MAN

Titanium is the gold standard among materials used for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, titanium becomes an oxide that is biocompatible and able to induce osseointegration. There are three allotropic forms of titanium dioxide: brookite, rutile and anatase. Anatase can be prepared as a colloidal suspension and then used to coat surfaces. Anatase coating (AC) can potentially have specific biologic effects. Here we test the effect of AC on bone throughout an in vivo study by using spiral dental implants covered with AC and then inserted in humans. The histologic analysis has demonstrated that (1) bone growth at least equal around AC and standard coating fixtures but (2) AC fixtures have an antibacterical propriety that protect implants from subsequent peri-implantitis. This study demonstrated that AC implant guarantee a good osseointegration of normal titanium implants giving in addition antibacterical propriet

EVALUATION OF A NEW NANO-COATING ON IMPLANT OSSEOINTEGRATION: A STUDY ON SPIRAL FIXTURES INSERTED IN NEW ZEALAND WHITE RABBITS

Titanium is the gold standard among materials used for prosthetic devices because of its good mechanical and chemical properties. When exposed to oxygen, titanium becomes an oxide that is biocompatible and able to induce osseointegration. There are three allotropic forms of titanium dioxide: brookite, rutile and anatase. Anatase can be prepared as a colloidal suspension and then used to coat surfaces. Anatase coating (AC) can potentially have specific biologic effects. Here we test the effect of AC on bone throughout an in vivo study by using spiral dental implants covered with AC and then inserted in rabbit tibia. The histologic analysis has demonstrated that (1) bone growth is equal around AC and standard fixtures but (2) AC fixtures have an antibacterical propriety that protect implants from subsequent peri-implantitis. This study demonstrated that AC implant inserted in rabbit tibia guarantee a good osseointegration of normal titanium implants giving in addition antibacterical propriet

Biphosphonates-related osteonecrosis of the jaw: multicenter study

Biphosphonates-related osteonecrosis of the jaw is defined as an exposure of necrotic bone in maxillofacial region,which persists more than 8 weeks in patients treated or,in course of treatment whit biphosphonate, not been subjected to radiation therapy of the jaw . Biphosphonate compounds used to treat osteoporosis and malignant bone metastasis.despite yhe benefits related to the use of these medications ,osteonecrosis of the jaw is a significant complication in a subset of patients receiving these drugs. This complication occurs either spontaneously or after a simple dento-alveolar surgery. This study was conducted to evaluate the correlation between the onset of onj and biphosphonate treatment,through descriptive and statistical data analysis, extracted from our study population,and correlation with data offered by literature

Synthesis, characterization, and electrochemical behavior of mono- and bimetallic ruthenium and rhenium allenylidenes bearing multiconjugated organic spacers

Novel monoallenylidenes of Ru and Re, homobimetallic Ru/Ru and heterobimetallic Ru/Re complexes bridged by multiconjugated aromatic organic spacers such as bianthracenylidene and biphenylene were obtained and characterized by conventional spectroscopic techniques and elemental analysis. Electrochemical measurements coupled to spectroelectrochemistry and EPR spectroscopy proved that in the bis(allenylidene) complexes an electronic communication is present between either the two allenylidene bridges or the two metal centres, enticing extended intramolecular electronic mobility

Synthesis, characterisation and molecular structure of Re(III) 2-oxacyclocarbenes stabilised by a benzoyldiazenido ligand

A family of new Fischer-type rhenium() benzoyldiazenido-2-oxacyclocarbenes of formula [(ReCl2{η1-N2C(O)- Ph}{ C(CH2)nCH(R)O}(PPh3)2] [n = 2, R = H (2), R = Me (3); n = 3, R = H (4), R = Me (5)] have been prepared by reaction of [ReCl2{η2-N2C(Ph)O}(PPh3)2] (1) with ω-alkynols, such as 3-butyn-1-ol, 4-pentyn-1-ol, 4-pentyn-2-ol, 5-hexyn-2-ol in refluxing THF. The correct formulation of the carbene derivatives 2-5 has been unambiguously determined in solution by NMR analysis and confirmed for compounds 2–4 by X-ray diffraction methods in the solid state. All complexes are octahedral with the benzoyldiazenido ligand, Re{N2C(O)Ph}, adopting a “single bent” conformation. The coordination basal plane is completed by an oxacyclocarbene ligand and two chlorine atoms. Two triphenylphosphines in trans positions with respect to each other complete the octahedral geometry around rhenium. The reactivity of 1 towards different alkynes and alkenes including propargyl- and allylamine has been also studied. With propargyl amine, monosubstituted or bisubstituted complexes, [(ReCl2{η1-N2C(O)Ph}{η1-NH2- CH2C CH}n(PPh3)3 n] [n = 1 (6); n = 2 (7)], have been isolated depending on the reaction conditions. In contrast, the reaction with allylamine gave only the disubstituted complex [(ReCl2{η1-N2C(O)Ph}{η1-NH2CH2CH CH2}2(PPh3)] (8). The molecular structure of the monosubstituted adduct 6 has been confirmed by X-ray analysis in the solid state

BISPHOSPHONATES-RELATED OSTEONECROSIS OF THE JAW: MULTICENTRE STUDY

Bisphosphonate-related osteonecrosis of the jaw is defined as an 'exposure of necrotic bone in maxillofacial region, which persists more than 8 weeks in patients treated or, in course of treatment with bisphosphonates, not been subjected to radiation therapy of the jaw. Bisphosphonates are compounds used to treat osteoporosis and malignant bone metastasis. Despite the benefits related to the use of these medications, osteonecrosis of the jaws is a significant complication in a subset of patients receiving these drugs. This complication occurs either spontaneously or after a simple dento-alveolar surgery. This study was conducted to evaluate the correlation between the onset of ONJ and bisphosphonate treatment, through descriptive and statistical data analysis, extracted from our study population, and correlation with data offered by literature