Phosphonate complexes

Sm complexes with phosphonate ligands were found to target actively growing bone (i.e., tumors fractures).152 Several 153Sm phosphonate complexes were synthesized and evaluated in... 

Kinetic studies have shown that electrophilicity in the iron triad is strongly metal dependent with Fe Ru, Os, and the nucleophilic reactivity order is PPh3 > P(0-tBu)3. Adducts 237 (PR3 = phosphites) react with water to give the cyclohexadienyl phosphonate complexes 239. Complex 235 is a effective catalyst for the conversion of phosphites to HP(0)(0R)2 (99,146,147) [Eq. (29)]. In a similar fashion, benzene ruthenium dications... 

Figure 6. Chelation sphere about the metal in the yMIPS/NAD+/2-deoxyglucitol-6-(E)-vinyl phosphonate complex. Protein amino acids are shown with dark lines and NAD+ is shown with less dark lines.

The rhodium anionic bis(phosphonate) complex [Rh(C5Me5)(I) PO-(OMe),, ] , can act as a tridentate ligand with the halogen atom as one of the donor centers (132). This behavior can be enhanced by introducing a pz group instead of the halogen atom. Bimetallic derivatives of the formula [Rh(C5Me5) PO(OMe)2 2(/i-pz )M] (M = Na or Tl) were prepared by addition... 

A number of phosphate and phosphonate complexes have been reported. These are important because of the role of [(V0)2P207] in the selective oxidation of n-butane to maleic anhydride.734 Representative complexes include Vra bound to various protonation states ofphosphate/pyro-phosphate,734,735 complexes containing additional cations, 6 and other anions.7, 738 A variety of structural motifs can form, and some of these are structural analogs of V111 DNA interactions.739 These types of complexes and interactions are of interest since it has been shown that various forms of vanadium can cleave DNA.740,741... 

In an attempt to apply this mechanism to a polyester formation and to investigate the single steps involved on a molecular basis one can for instance start with the CALB-phosphonate complex 1LBS [6] as the initial structure, as it is structurally close to the intermediate structure of an acylated Ser10s that certainly has to be passed through during an enzymatic polymerization process. In accordance with the accepted mechanism for serine hydrolases the enzymatic process consists of two mechanistically important steps. These are, in the case of for instance, a potential enzymatic esterification of adipic acid with 1,6-hexanediol ... 

DPD was developed at Hochst, Germany (Schwarz and Kloss 1981 Schwarz et al. 1991), and compared favorably with MDP (Buell et al. 1982 Godart et al. 1986 Hale et al. 1981 Pauwels et al. 1983 Schroth et al. 1984). DPD is another efficient phosphonate complex that has been widely used as Teceos. The merits of available diphosphonate bone scanning agents have been discussed by Fogelman 1982. 

Following intravenous injection, 45-50% of " Tc-diphosphonates (MDP, HDP, DPD) accumulate in the skeleton, while most of the rest is excreted in the urine. Maximum bone accumulation occurs 1 h after injection and remains constant for 72 h. The determining factors for bone uptake of " Tc-phosphonate complexes are an increased blood flow to the skeleton and reactive bone formation, causing avid extraction by the bone mineral matrix (Jones et al. 1976 Sahni et al. 1993). Symmetric areas of increased activity concentration are seen in the metaphyseal zones in the growing skeleton. Ankles, knees, elbows, wrists, shoulder joints, pelvic bones, and vertebrae show increased uptake in the normal anterior bone scintigram (Saha 1987). 

The disappearance of " Tc-phosphonate complexes from blood is affected by skeletal fixation and urinary excretion. Blood clearance proceeds with three half-times of elimination, a rapid phase (Ti/2 = 3.5 min), an intermediate phase (Ti/2 = 27 min), and a slow phase (Ti/2=144 min). Transfer to the bone matrix corresponds to the intermediate phase. The total radioactivity in blood at 5 min, 2, 4, and 24 h after the intravenous injection was measured as 40, 10, 5.8, and 2.3%, respectively (Subramanian et al. 1975 a). 

Polystyrene resins that have aminophosphonate chelating groups are highly selective towards calcium ion. Such a resin, e.g., Duolite ES467 (Rohm and Haas), when added to a strong brine solution (25%) contaminated with 10 mg/liter of calcium ion will selectively remove the calcium ion, forming calcium amino-phosphonate complex (XXVII), until only 0.02 mg/liter remains. This process is particularly useful for purifying the brine used in the chlor-alkaK cell described earlier. 

Kim. H. Lipscomb. W.N. Comparison of the structures of three carboxypeptidase A-phosphonate complexes determined by X-ray crystallography. Biochemistry 1991. 30. 8171-8180. 

Figure 7 Imprinting with amidinium-phosphonate complexes to generate catalytic MIPs for the hydrolysis of carbonates and carbamates.

Strong Lewis acids such as BFj [405] and BCI3 [406] form with dialkyl H-phosphonates complexes of the following type ... 

Phosphonate complexes are liable to undergo Arbusov rearrangement to form phosphinates (9.133) and phosphite complexes may undergo similar rearranganent to phosphonates (9.134). The liability... 

Nanocrystalline Ti02 (or Zr02) films on ITO substrates andTi02 (or Zr02) colloids were prepared by a method described in Refs. 379, 388. The films were heated to 400 °C for 30 min, cooled and immersed in solutions ca. 10 M in phosphonated complexes in ethanol solution for 16 h. After derivatization, the electrodes were rinsed with ethanol and stored in a fresh ethanol until use [377, 388-392]. Surface coverages were determined by spectroscopic measurement of the amount of complex in M ethanol solution... 

Sm phosphonate complexes used as analgesics and as therapeutics for bone cancer ifiT emitter)... 

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