New metalloporphyrins bearing one or two aryl-aza-crown ether moieties at meso-positions have been synthesized using a palladium catalyzed amination reaction and fully characterized by spectral techniques. X-Ray structural data have been presented for the zinc and copper complexes of mono-substituted aza-crown ether appended metalloporphyrins. UV-Vis and (1)H NMR spectroscopic studies showed th...

Wedding cake growth is a layer-by-layer growth model commonly observed in epitaxial growth of metal films, featured by repeated nucleation of new atomic layers on the topmost surface owing to the confinement of the Ehrlich-Schwoebel (ES) barrier. Herein, we report an inverted wedding cake growth phenomenon observed in two-dimensional nanostructure evolution. Through a dynamically controlled vap...

Crown ethers have the remarkable property of recognizing and binding specific metal cations in complex mixtures. We propose to combine molecular recognition with molecular electric conductance. The question we address is: can the event of binding a cation be sensed by a change in conductance? Specifically, we study a short molecular wire (MW) containing a crown-6 molecule connected via sulfur a...

The processes involved in transport of K and Na by the carrier ionophores valinomycin and 18-crown-6 ether across cell membranes have been elucidated using quantum mechanical modelling: 1. Formation of the {ionophore-M} complex: desolvation (ΔGdesolv) of the central cavity of the ionophore, change in configurational energy TΔS, desolvation of the M(H2O)6-7 + 2. Desolvation of the {ionophore-M} ...

The method, known as the Hall Technique (HT) involves sealing early caries in primary molars with no tooth cutting, no removal of caries, and no local anaesthesia. That is “no needle "and "no drill”. A preformed metal crown (PMC), also referred to as a stainless steel crown, is cemented directly over caries that does not extend radiographically beyond the middle third of dentine. The sealing of...

Reconstruction of hard dental tissue after endodontic treatment is a difficult and important duty of the dentist. According to the general opinion, endodontically treated teeth are inferior in quality, more brittle, predisposed to fractures and cracking. Logically, such teeth require reconstruction to prevent fractures, cracks, and bacterial microleakage leading to reinfection. The procedure of...

The reactions of two diazabutadiene ligands, Ar-DAB [(ArN CH)2, Ar = 2,6-Pr2C6H3] and Bu-DAB [(BuN CH)2] with either GaI or an AlI3/Al mixture have afforded the paramagnetic compounds, [{IGa (Bu-DAB)}2], [I2Ga (Bu-DAB)] and [I2Al (Ar-DAB)] which have been characterised by X-ray crystallography and EPR spectroscopy. In addition, the diamagnetic, ionic complex, [I2Al (Ar-DAB)]I, has been prepared...

PURPOSE The aim of this investigation was to measure the temperature increase due to heat transferred to the implant-bone interface when the abutment screw channel is accessed or a metal-ceramic crown is sectioned buccally with diamond or tungsten carbide bur using an air rotor, with or without irrigation. MATERIALS AND METHODS Cobalt-chromium copings were cemented onto straight titanium abut...

The Sn, Cl and water O atoms of the title compound, [Sn(2)(CH(3))(4)Cl(4)(H(2)O)(2)]·C(10)H(20)O(5), lie on a special position of 2 site symmetry. The Sn(IV) atom shows cis-C(2)SnCl(2)O trigonal-bipyramidal coordination [C-Sn-C = 157.0 (1)°]; however, two [Me(2)SnCl(2)(H(2)O)] units are linked by a tin-chlorine bridge [Sn←Cl = 3.247 (1) Å] across a center of inversion, generating a dinuclear sp...

In the title compound, [Co(C25H30N4O4)2](ClO4)3·CH3OH·H2O, the metal atom is coordinated by two tridentate crown ether terpyridine ligands, forming a distorted CoN6 octa-hedron. The three pyridine rings in each crown-terpyridine ligand are approximately coplanar [maximum deviations = 0.088 (12) and 0.102 (15) Å] and the mean planes through the three pyridine rings are perpendicular to each othe...