Mixed-valent manganese phosphonate clusters [Mn(II)(8)Mn(III)(2)O(2)(O(3)PC(10)H(7))(4)(C(6)H(5)CO(2))(10)(py)(4)(H(2)O)(2)] (1) and [Mn(II)(4)Mn(III)(9)O(4)(OH)(2)(O(3)PC(10)H(7))(10)(C(6)H(5)CO(2))(5)(py)(8)(H(2)O)(6)] (2) are reported. Compound 1 is the first example of manganese phosphonate clusters prepared through a microwave-assisted technique. While compound 2 is obtained under ambient ...

The C-P lyase complex in bacteria catalyzes the transformation of phosphonates to orthophosphate under conditions of phosphate starvation. The first committed step in the C-P lyase-catalyzed reaction is the displacement of adenine from MgATP by phosphonate substrates, yielding ribose-1-phosphonate-5-triphosphate. In the C-P lyase complex, this reaction is catalyzed by the nucleosidase PhnI and ...

Starting from enantiomeric pure 1-[(3S,5R)- and 1-[(3R,5S)-3-(hydroxymethyl)-2-methylisoxazolidin-5-yl]-5-methylpyrimidine-2,4(1H,3H)-diones (-)7a and (+)7b, obtained by lipase-catalyzed resolution, pure diethyl{[(3S,5R)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)isoxazolidin-3-yl]methyl}phosphonate (-)12a and diethyl{[(3R,5S)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidi...

A sensitive and reproducible method for the direct spectrophotometric determination of zirconium is reported. The method is based on zirconium forms a stable bluish violet colour complex with Chrome Azurol S (CAS) which has maximum absorption at 598 nm at pH 4.2. The complex obeys Beer’s law in the concentration range of 1-7 μg/mL. Detection limit, molar absorptivity and Sandell’s sensitivity w...

Aluminium based nanostructured materials with additions of 0.5, 1 and 1.5 weight% of zirconium have been produced and sintered using the spark plasma sintering technique in order to promote the nucleation of ZrAl3 platelets. The mechanical behaviour of all these nanocomposites was determined by means of the Small Punch Test. Zirconium additions significantly decrease the mechanical properties o...

It is well known that the structure of ZrO2 powder synthesized by low temperature calcination of hydrous zirconia is strongly affected by the nature and properties of precursors. In the present paper, we combined a precipitation/restructuring approach (bottom-up/top-down methodology) to produce zirconium hydroxide nanoparticles that transform into stable nanophasic tetragonal zirconia by low te...

The favourable mechanical properties and high biocompatibility of the newly developed mixed ceramics composed of zirconium oxide and aluminium oxide have continuously extended the scope of their application. Rotating instruments on a zirconium oxide basis are regarded as superior to metal burs in dentoalveolar surgery in terms of favourable temperature effects on the surrounding bone tissue and...

Sialic acid (Neu5Ac, 1), a constituent of sialoglycoproteins1 and gangliosides,2 mediates a number of intercellular and cell-virion recognition events.3 Analogs of sialic acid are interesting as potential inhibitors for medicinally important target proteins, such as neuraminidase of the influenza virus.4 The syntheses of sialic acid and its analogs have been the subject of extensive research.5 ...

The search of reprolysin inhibitors offers the possibility of intervention against both matrixins and ADAMs. Here we report the crystal structure of the complex between adamalysin II, a member of the reprolysin family, and a phosphonate inhibitor modeled on an endogenous venom tripeptide. The inhibitor occupies the primed region of the cleavage site adopting a retro-binding mode. The phosphonat...