Linear dicarboxylates

The isoreticular MOFs based on the Zn40(C0i)6 SBU also possesses favorable sorption properties for the storage of molecular hydrogen. At 77 K, microgravimetric sorption measurements gave H2 (mg/g) values of 13.2,15.0, 16.0, and 12.5 for IRMOF-1, IRMOF-8, IRMOF-11, and MOF-177, respectively. At the highest pressures attained in the measurements, the maximum uptake values for these frameworks are 5.0, 6.9, 9.3, and 7.1 molecules of H2 per Zn4OI unit where L stands for a linear dicarboxylate. 

Addition of a dicarboxylate to [Zn(tmtsc)2]2+ leads to a variety of structural types, with the major factor determining the structure adopted being the relative orientation of the carboxylate groups in the anion. Linear dicarboxylates such as fumarate and terephthalate gives hydrogen-bonded tape structures, though the terephthalate compound contains expanded dimeric cations in the observed product [ Zn(tmtsc)(0H2) 2(p-terephthalate)]terephthalate 2H20 30 [163]. 

Fig. 2 MOFs constructed from linear dicarboxylate linkers showing different pore sizes as a result of different lengths of bridging ligands...

Cu(lOO), chiral Fe(TMA)4 clusters are formed. This is associated with the deprotonation of the carboxylic acid groups of TMA upon adsorption on the Cu substrate at temperatures above 250 K. Upon annealing at 400 K, homochiral porous network structures can be built up from these Fe(TMA)4 clusters in a hierarchical manner (Figure 6). The nanocavities of these networks have been used as hosts for the accommodation of Ceo and small biomolecules. The same group also investigated such important key factors for self-assembly as self-recognition, self-selection, self-repair, and dynamic self-organization for a library of linear dicarboxylates and bipyridines codeposited with Fe atoms onto a Cu(lOO) surface. ... 

An array of closed stmctures, either polygons or polyhedra, may be formed with [cw-Mo2(DAniF02(MeCN)4]. The simplest of these polygons, called loops (Fig. 3a), have two Mo2" units joined by two dicarboxylate linkers. Molecular triangles and squares (Fig. 3b and c) are formed by procedures similar to that used to form loops. It should be noted that for loops, triangles, and squares, the ratio of the Mo2" comer pieces to the dicarboxylate is the same, that is, 1 1. The formation of one polygon type versus another is determined principally by the shape of the linker, namely, the disposition of the carboxylate chelates relative to one another. Linear dicarboxylates favor the squares, while bent dicarboxylates tend to produce loops. Finally, closed polyhedra, or cages, may form when [cis-Mo2(DAniF)2(MeCN)4] is used... 

We have discussed the usage of terminal ligands to make photoreactive CPs before (Sections 2.2,4.1, and 5.1). Here the use of 4-spy for linking the 2D layers to form interpenetrated 3D structures by [2-1-2] cycloaddition reaction is illustrated. The paddle-wheel SBU, Zn2(02C-C)4) has been found in two isotypical interdigitated photoreactive CPs, [Zn2(cca)2(4-spy)2] (40) and [Zn2(ndc)2(4-spy)2] (41). The linear dicarboxylate ligands 4-carboxycinnamate (cca) or 2,6-naphthalenedicarboxylate (ndc) are connecting the paddle-wheel nodes to form the 2D layer structure with... 

G-20 Dicarboxylic Acids. These acids have been prepared from cyclohexanone via conversion to cyclohexanone peroxide foUowed by decomposition by ferrous ions in the presence of butadiene (84—87). Okamura Oil Mill (Japan) produces a series of commercial acids based on a modification of this reaction. For example, Okamura s modifications of the reaction results in the foUowing composition of the reaction product C-16 (Linear) 4—9%, C-16 (branched) 2—4%, C-20 (linear) 35—52%, and C-20 (branched) 30—40%. Unsaturated methyl esters are first formed that are hydrogenated and then hydrolyzed to obtain the mixed acids. Relatively pure fractions of C-16 and C-20, both linear and branched, are obtained after... 

Plasticizers can be classified according to their chemical nature. The most important classes of plasticizers used in rubber adhesives are phthalates, polymeric plasticizers, and esters. The group phthalate plasticizers constitutes the biggest and most widely used plasticizers. The linear alkyl phthalates impart improved low-temperature performance and have reduced volatility. Most of the polymeric plasticizers are saturated polyesters obtained by reaction of a diol with a dicarboxylic acid. The most common diols are propanediol, 1,3- and 1,4-butanediol, and 1,6-hexanediol. Adipic, phthalic and sebacic acids are common carboxylic acids used in the manufacture of polymeric plasticizers. Some poly-hydroxybutyrates are used in rubber adhesive formulations. Both the molecular weight and the chemical nature determine the performance of the polymeric plasticizers. Increasing the molecular weight reduces the volatility of the plasticizer but reduces the plasticizing efficiency and low-temperature properties. Typical esters used as plasticizers are n-butyl acetate and cellulose acetobutyrate. 

Reactions of alkanedicarboxylic acids with sulfur tetrafluoride afford, in general, mixtures of bis(trifluorQmethyI)allcanes, cyclic 0(,a,a, a -tetrafluoro ethers, linear bis(pentafluoroalkyl) ethers, and polyfluoroethers The cyclic ethers constitute the major products of the reactions with alkane-1,2 dicarboxyhc acids, they are also formed in the reactions with alkane-1,3-dicarboxylic acids but not with 1,1- nor 1,4-dicarboxylic acids [211] (equation 105)... 

Linear step-growth polymerizations require exceptionally pure monomers in order to ensure 1 1 stoichiometry for mutually reactive functional groups. For example, the synthesis of high-molecular-weight polyamides requires a 1 1 molar ratio of a dicarboxylic acid and a diamine. In many commercial processes, the polymerization process is designed to ensure perfect functional group stoichiometry. For example, commercial polyesterification processes often utilize dimethyl terephthalate (DMT) in the presence of excess ethylene glycol (EG) to form the stoichiometric precursor bis(hydroxyethyl)terephthalate (BHET) in situ. 

Condensation polymerization involves the loss of a small molecule, often water or HC1, when monomers are combined. Dacron is more linear than the polymer obtained from benzene-1,2-dicarboxylic acid and ethylene glycol, so Dacron can be more readily spun into yarn. 

Hydroxycarbonylation and alkoxycarbonylation of alkenes catalyzed by metal catalyst have been studied for the synthesis of acids, esters, and related derivatives. Palladium systems in particular have been popular and their use in hydroxycarbonylation and alkoxycarbonylation reactions has been reviewed.625,626 The catalysts were mainly designed for the carbonylation of alkenes in the presence of alcohols in order to prepare carboxylic esters, but they also work well for synthesizing carboxylic acids or anhydrides.137 627 They have also been used as catalysts in many other carbonyl-based processes that are of interest to industry. The hydroxycarbonylation of butadiene, the dicarboxylation of alkenes, the carbonylation of alkenes, the carbonylation of benzyl- and aryl-halide compounds, and oxidative carbonylations have been reviewed.6 8 The Pd-catalyzed hydroxycarbonylation of alkenes has attracted considerable interest in recent years as a way of obtaining carboxylic acids. In general, in acidic media, palladium salts in the presence of mono- or bidentate phosphines afford a mixture of linear and branched acids (see Scheme 9). 

GC/MS has also been used to investigate acidic and neutral fractions (after alkaline hydrolysis, separation and trimethylsilylation) of a resinous sample collected from a flint flake dated back to the lower Palaeolithic (roughly 200 000 BC) and recovered near Arezzo in Italy [11]. The results show that the organic material recovered on the flint flake was a pitch obtained from birch bark by a pyrolysis type process. In fact, the main components of the acidic fraction are a series of linear a,oo-dicarboxylic acids ranging from 16 to 22 carbon atoms and a series of oo-hydroxycarboxylic acids ranging from 16 to 22 carbon... 

Without added acid or nucleophile the lability of the starting compound is very low (<1 x 10"8 s"1) most probably because of the efficient ring-closing process [18]. The second step depends linearly on the pH with a rate constant of 1.61 x 10"4 M 1 s 1. In the presence of added Cl-, the final product of the hydrolysis is m-DDP although the relevance of similar process in vivo was questioned [18]. It has been reported that carboplatin bound to DNA retains the dicarboxylate group, probably as a monodentate ligand [19]. 

Subsequent ring closure of the 2,5-diarylamino-1,4-benzoquinone-3,6-dicarboxylic acid (61) is performed in concentrated sulfuric acid (or with thionyl chloride/ni-trobenzene) to afford the linear trans-quinacridone quinone 62. 

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