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PubMed2003

Replacing the pyrophosphate group of HMB-PP by a diphosphonate function abrogates Its potential to activate human gammadelta T cells but does not lead to competitive antagonism.

The immunological characterization of (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), and its methylenediphosphonate analogue, HMB-PCP, is described. With an EC(50) of 0.1-0.2 nM, HMB-PP is significantly more potent in stimulating human Vgamma9/Vdelta2 T cells than any other compound described so far. However, replacing the pyrophosphate by a P-CH(2)-P function abrogates the bioactivity drastically, with HMB-PCP having a EC(50) of only 5.3 microM.

Binding, Competitive↗
PubMed1988

Radiopharmacological profiles of tracers under pathophysiological conditions. 99mTc-methylene diphosphonate uptake by bone in altered thyroid status.

The uptake of 99mTc-MDP, a skeletal radiotracer, was studied at early and late (3 h) time intervals in rats induced with altered thyroid status. Thyroid dysfunction resulted in disturbances in bone mineral metabolism. Rats rendered hypothyroid showed an overall retardation in growth and also considerably reduced skeletal uptake, especially at early time periods. On the other hand, rats rendered hyperthyroid did not show any significant alteration of the skeletal uptake as compared with controls despite enhanced bone turnover normally observed in hyperthyroidism.

Animals↗
PubMed2003

Novel layered ruthenium diphosphonate containing a mixed valent diruthenium paddlewheel core.

This paper reports the synthesis and crystal structure of a novel mixed valence ruthenium(II,III) compound, (NH(4))(3)Ru(2)(hedp)(2).2H(2)O (1), where hedp represents 1-hydroxyethylidenediphosphonate. It has a two-dimensional structure in which the paddlewheel diruthenium(II,III) units of Ru(2)(hedp)(2) are cross-linked through the phosphonate groups. The layers are stacked along the [100] direction with strong intra- and interlayer hydrogen bonds. Primary magnetic results are presented.

Journal Article↗
PubMed2004

Solid-state coordination chemistry of the oxomolybdate-organodiphosphonate/nickel-organoimine system: structural influences of the secondary metal coordination cation and diphosphonate tether lengths.

The hydrothermal reactions of a molybdate source, a nickel(II) salt, tetra-2-pyridylpyrazine (tpyprz), and organodiphosphonic acids H(2)O(3)P(CH(2))(n)()PO(3)H(2) (n = 1-5) of varying tether lengths yielded a series of organic-inorganic hybrid materials of the nickel-molybdophosphonate family. A persistent characteristic of the structural chemistry is the presence of the [Mo(5)O(15)(O(3)PR)(2)](4)(-) cluster as a molecular building block, as noted for the one-dimensional materials [[Ni(2)(tpyprz)(2)]Mo(5)O(15)[O(3)P(CH(2))(4)PO(3)]]x6.65H(2)O (6x6.65H(2)O) and [[Ni(2)(tpyprz)(2)]Mo(5)O(15)[O(3)P(CH(2))(5)PO(3)]]x3.75H(2)O (8x3.75H(2)O), the two-dimensional phases [[Ni(4)(tpyprz)(3)][Mo(5)O(15)(O(3)PCH(2)CH(2)PO(3))](2)]x23H(2)O (3x23H(2)O) and [[Ni(3)(tpyprz)(2)(H(2)O)(2)](Mo(5)O(15))(Mo(2)O(4)F(2))[O(3)P(CH(2))(3)PO(3)](2)]x8H(2)O (5x8H(2)O), and the three-dimensional structures [[Ni(2)(tpyprz)(H(2)O)(3)]Mo(5)O(15)[O(3)P(CH(2))(3)PO(3))]]xH(2)O (4xH(2)O) and [[Ni(2)(tpyprz)(H(2)O)(2)]Mo(5)O(15) [O(3)P(CH(2))(4)PO(3)]]x2.25H(2)O (7x2.25H(2)O). In the case of methylenediphosphonic acid, the inability of this ligand to tether adjacent pentanuclear clusters precludes the formation of the common molybdophosphonate building block, manifesting in contrast a second structural motif, the trinuclear [(Mo(3)O(8))(x)(O(3)PCH(2)PO(3))(y)] subunit of [[Ni(tpyprz)(H(2)O)(2)](Mo(3)O(8))(2) (O(3)PCH(2)PO(3))(2)] (1) which had been previously observed in the corresponding methylenediphosphonate phases of the copper-molybdophosphonate family. Methylenediphosphonic acid also provides a second phase, [Ni(2)(tpyprz)(2)][Mo(7)O(21)(O(3)PCH(2)PO(3))]x3.5H(2)O (9x5H(2)O), which contains a new heptamolybdate cluster [Mo(7)O(21)(O(3)PCH(2)PO(3))](4)(-) and a cationic linear chain [Ni(tpyprz)](n)(4n+) substructure. The structural chemistry of the nickel-molybdophosphonate series contrasts with that of the corresponding copper-molybdophosphonate materials, reflecting in general the different coordination preferences of Ni(II) and Cu(II). Consequently, while the Cu(II)-organic complex building block of the copper family is invariably the binuclear [Cu(2)(tpyprz)](4+) subunit, the Ni(II) chemistry with tpyprz exhibits a distinct tendency toward catenation to provide [Ni(3)(tpyprz)(2)](6+), [Ni(4)(tpyprz)(3)](8+), and [Ni(tpyprz)](n)(4n+) building blocks as well as the common [Ni(2)(tpyprz)](4+) moiety. This results in a distinct structural chemistry for the nickel(II)-molybdophosphonate series with the exception of the methylenediphosphonate derivative 1 which is isostructural with the corresponding copper compound [[Cu(2)(tpyprz)(H(2)O)(2)](Mo(3)O(8))(2)(O(3)PCH(2)PO(3))] (2). The structural chemistry of the nickel(II) series also reflects variability in the number of attachment sites at the molybdophosphonate clusters, in the extent of aqua ligation to the Ni(II) tpyprz subunit, and in the participation of phosphate oxygen atoms as well as molybdate oxo groups in linking to the nickel sites.

Journal Article↗
PubMed2005

Mixed-valent diruthenium diphosphonate with kagomé structure.

This paper reports the first example of diruthenium phosphonate with kagomé structure, namely, [NH3(CH2)4NH3][Ru2(hedpH(0.5))2].2H2O (hedp = 1-hydroxyethylidenediphosphonate). The compound contains kagomé layers that are linked by very strong hydrogen bonds into a nanoscale kagomé structure. Ferromagnetic interactions are mediated between the paramagnetic diruthenium units.

Journal Article↗
PubMed2003

A two-step field-induced magnetic transition in a novel layered cobalt diphosphonate.

Compound Na6Co7(hedp)2(hedpH)4(H2O)4 x 8H2O (hedp = 1-hydroxyethylidenediphosphonate) with a novel layer structure is reported in this paper. The layer maybe viewed as made up from two types of chains each of composition Co3(hedp)2 and Co2(hedpH)2. Magnetic measurements at 1.8 K reveal a metamagnetic transition at ca. 6.5 kOe, followed by a second transition to a ferromagnetic state at ca. 30 kOe.

Journal Article↗