Complex Phosphate Salts

The synthesis and crystal structure analyses of complex salts with mixed cations and mixed anions (which include (HP04) (H2P04) , oxalate and other species) are being reported in ever-increasing numbers [77-83]. Examples are 

Some structures of this type have important properties arising from the cavities they contain and are included under Section 5.7. Complex phosphate salts are involved in soil chemistry (Chapter 12.2). Mixed-ion acid salts and their H-bonded structures, which have electronic applications, are dealt with in Chapter 13.1. 

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Calcinm is an essential element in living matter. It is the major component of bones and teeth the calcinm ion is present in a complex phosphate salt, hydroxyapatite, Ca5(P04)30H. A characteristic fnnction of Ca ions in living systems is the activation of a variety of metabolic processes. Calcium plays a vital role in heart action, blood clotting, mnscle contraction, and nerve impulse transmission. 

Organic cations such as protonated hexamethylene diamine and 1,4 diazabicyclo-(2,2,2)-octane (DABCO) are capable of forming complex phosphate salts with channel or cavity strnctnres formed from negatively charged frameworks [105], Neutral organic molecules may also act as templates and in many cases can afterwards be removed without resulting in collapse of the cavity strnctnre. 

Iron pentacarbonyl and l-methoxy-l,4-cyclohexadiene react as shown by Birch and oo-workera, but in dibutyl ether this solvent has been found superior. The tricarbonyl(methoxy-l,3-cyclohexadiene)iron isomers undergo hydride abstraction with triphenylmethyl tetrafluoro-borate to form the dienyl salt mixture of which the 1-methoxy isomer is hydrolyzed by water to the cyclohexadienone complex. The 2-methoxy isomer can be recovered by precipitation as the hexafluoro-phosphate salt. By this method the 3-methyl-substituted dienone complex has also been prepared from l-methoxy-3-methylbenzene. The use of the conjugated 1-methoxy-1,3-cyclohexadiene in Part B led to no increase in yield or rate and resulted chiefly in another product of higher molecular weight. An alternative procedure for the dienone is to react tricarbonyl(l,4-dimethoxycyclohexadiene)iron with sulfuric acid. ... 

Write the formula for the phosphate salt (if the complex ion is a cation) or the aluminum salt (if the complex ion is an anion) for the ions in Question 5. 

Adsorption inhibitors act by forming a film on the metal surface. The action of traditional oil-based red lead paint formulations presumably involves the formation of soaps and the precipitation of complex ferric salts that reinforce the oxide film. There has been substantial interest in recent years in development of replacements for lead-based and chromate-based inhibitor systems. Adsorption inhibitors based on pol3rmers have been of particular interest. In this volume, Johnson et al. and Eng and Ishida discuss inhibitors for copper 2-undecylimidazole is shown to be effective in acid media, where it suppresses the oxygen reduction reaction almost completely. Polyvlnyllmidazoles are shown to be effective oxidation inhibitors for copper at elevated temperatures. Also in this volume, Chen discusses the use of N-(hydroxyalkyl)acrylamide copolymers in conjunction with phosphate-orthophosphate inhibitor systems for cooling systems. 

An extension of this methodology, by hexafunctionalization of the arene group in 13 using ferrocenylbutyl iodide 14 under basic conditions, gave the hexafluoro-phosphate salt of the heptanuclear Fe(Il) complex cation 15 in 65% yield. Photolysis of 15, under similar conditions which converted 8 into 9, led to isolation of the neutral ferrocenyl complex 16 by selective decomplexation of the central... 

BF3 reacts smoothly, in inert solvents, with alkali metal sulfates and phosphates to give stable 2 1 and 3 1 complexes (Table 9), whereas the intermediate complexes that form with NOT, SO and COl- decompose to [BF4] and B203.55 Brownstein et al. have established114 that BF3 reacts easily with alkylammonium salts in CH2C12 or liquid S02. [BF3A]- complex anions are formed with the salts of strong acids (equation 17) whereas complexes with salts of weak acids easily undergo disproportionation (equation 18) and/or conversion into a 2 1... 

Most FR formulations are not resistant to leaching by water. Therefore, there have been increased efforts to develop leach-resistant chemicals that can be impregnated into wood products for use in exterior or high-humidity applications. Some of the proposed leach-resistant systems include chemical combinations that form insoluble complexes, amino-resin systems, and monomers that polymerize in the wood. A common amino-resin system for exterior use is dicyandiamide phosphoric acid formaldehyde. Guanylurea phosphate-boric acid also is a commonly used organic phosphate salt for modern commercial FR wood. 

Interestingly, while no rearranged / -allylplatinum complex could be detected in solution for either the borate or phosphate salts, the crystals of the tetraphenylborate salt have the -allyI structure whereas the crystals of the hexafluorophosphate salt have the rf-allyl structure . This reflects differences in stabilization of the complex structure due to crystal packing, and thus strongly suggests that the rearrangement is a low energy... 

Attentiou will be focused ou phosphates of metallic elements and other small cations (H+, NH4+), although it should be uoted that a variety of phosphate salts of large orgauic or iuorgauic coordiuatiou complex catious are also knowu. Backgrouud informatiou of the chemistry of phosphates aud related phosphorus species can be found in the texts by Corbridge and Kanazawa see also Phosphorus Inorganic Chemistry). 

Similarly, supersaturation of saliva with respect to calcium phosphate salts is the driving force of calculus (i.e., mineralized dental plaque) and sialolith (i.e., salivary duct stones ) formation. In these cases, negatively charged phospholipids play a crucial role Ca + ions bind to the negative charges of such lipids, and inorganic phosphate associates with the bound calcium that forms a Ca-phosphate-phospholipid complex, which is an excellent nucleus of calcium-phosphate deposition. Salivary proteins may also play a role in this process because such complex formation occurs predominantly on lipids that are protein associated. The increase of pH facilitates these processes (13). 

Complex phosphates of uranium and the alkali or alkaline earth metals have been prepared by fusing an intimate mixture of the alkali phosphate with an excess of uranous oxide in a jdatinum Rose crucible through which carbon dioxide was passing. The fusion may be facilitated by the addition of a little alkali chloride. On slowly cooling the crucible, well-defined crystals of the double phosphate are formed. If the alkali metaphosphate is used, salts of the type RgU(P04)2 where R=K, Na R2=Ca, Sr, Ba, are obtained. 

Phosphate is better used when supplied by food than when supplied by phosphate salts, such as potassium phosphate. The food phosphate occurs largely as phosphate esters and, with gradual hydrolysis, enters the body relatively slowly and is used efficiently in the metabolic processes. Phosphate supplied as inorganic phosphate is rapidly absorbed, with a tendency to be excreted in the urine rather than to be used by tissues (Schuette and Linkswilcr, 1962). The phosphate in bran occurs largely in the form of phytic acid (inositol hexaphosphate). The phosphate groups of fhis compound may be only partially hydrolyzed in the gut- Phytic acid tends to be excreted via the fecal route as a complex with iron or calcium. 

However, the use of buffers in parenterals is not always benign, and numerous instances have been summarized where buffers or other excipients have caused stability problems.For instance, the com-plexation of Ca(II) and Al(III) with phosphate buffer solutions has been studied at great length, as well as the kinetic characteristics of the subsequent precipitation of calcium and aluminum phosphate salts. The use of metal complexing excipients, such as citric... 

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