Carboxy Function Research Articles

(Invited) Binder Investigation for Silicon Electrode of Lithium-Ion Batteries

Though the binder is not an active material and does not contribute capacity to lithium ion batteries (LIBs), it is an important ingredient for maintaining the integrity of the electrode, which helps to improve electrical contact between the active materials and conductive carbon black, improves the Li+ transport efficiency, reduces the internal resistance of Li-ion batteries and effectively depresses the crack formations and phase separation.Polyvinylidene fluoride (PVDF) is a polymer that is commonly used as a binder for both anode and cathode materials in LIBs. However, it is not suitable for Si electrode due to its poor binding capability and stability. Viewed as a next generation anode material, Si has been extensively studied due to its extremely high theoretical specific capacity of 3578 mAh/g (assuming Li15Si4 as intermediate product). However, silicon undergoes huge volume variations during repeated discharge and charge, which requires a strong binder to maintain the electrode mechanical integrity. Developing a high strength binder for silicon anodes has been considered as an efficient pathway to alleviate various capacity decay pathways.Polyacrylic acid (PAA) and its lithiated version (LiPAA), rich with carboxy function group, can provide stronger binding and are widely used as binder for Si electrode. In this work, we optimized Si electrode formulation by varying the binder composition. The optimized Si electrodes were electrochemically tested in both half cells and full cells. With improvement in electrochemical performance, cracks at the electrode level can still be observed for the cycled electrodes, which suggests that a stronger binder is required to mitigate volume expansion of Si electrodes and hold the particles together.We further studied the polyimide (PI) materials as binders for Si anodes in an attempt to achieve more stable cycling performance. In this work, we explore various PI crosslinking conditions and their effects on electrochemical performance. The optimized silicon electrode exhibits a higher tensile strength than that of conventional PAA binder. The strong adhesion of the PI binder suppresses the structural collapse of the Si negative electrode during lithiation/delithiation, enabling good capacity retention and stable cycle life.

Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging.

The increasing demand for reliable near-infrared (NIR) probes exhibiting enduring fluorescence in living systems and facile compatibility with biomolecules such as peptides, antibodies or proteins is driven by the increasing use of NIR imaging in clinical diagnostics. To address this demand, a series of carboxy-functionalized unsymmetrical squaraine dyes (SQ-27, SQ-212, and SQ-215) along with non-carboxy-functionalized SQ-218 absorbing and emitting in the NIR wavelength range were designed and synthesized followed by photophysical characterization. This study focused on the impact of structural variations in the alkyl chain length, carboxy functionality positioning, and spacer chain length on dye aggregation and interaction with bovine serum albumin (BSA) as a model protein. In phosphate buffer (PB), the absorption intensity of the dyes markedly decreased accompanied by pronounced shoulders indicative of dye aggregation, and complete fluorescence quenching was seen in contrast to organic solvents. However, in the presence of BSA in PB, there was a enhancement in absorption intensity while regaining the fluorescence coupled with a remarkable increase in the intensity with increasing BSA concentrations, signifying the impact of dye-BSA interactions on preventing aggregation. Further analysis of Job's plot unveiled a 2:1 interaction ratio between BSA and all dyes, while the binding studies revealed a robust binding affinity (Ka) in the order of 107/mol. SQ-212 and SQ-215 were further tested for their in vitro and in vivo imaging capabilities. Notably, SQ-212 demonstrated nonpermeability to cells, while SQ-215 exhibited easy penetration and prominent cytoplasmic localization in in vitro studies. Injection of the dyes into laboratory mice showcased their efficacy in visualization, displaying stable and intense fluorescence in tissues without toxicity, organ damage, or behavioral changes. Thus, SQ-212 and SQ-215 are promising candidates for imaging applications, holding potential for noninvasive cellular and diagnostic imaging as well as biomarker detection when coupled with specific vectors in living systems.

Fully Wood-Based Transparent Plates with High Strength, Flame Self-Extinction, and Anisotropic Thermal Conduction

Glasses and transparent plastics are used as daylighting face materials in buildings and vehicles. However, these transparent materials are mechanically inferior to other structural members such as metals, concretes, and fiber-reinforced plastics and have no contribution to the load-bearing capacities of whole structures incorporating them. Herein, we report clearly transparent and mechanically strong plate materials (haze 8%, strength 256 MPa) comprising solely wood-derived cellulose nanofibers (CNFs) with carboxy functionality. These plates have a millimeter thick laminated structure and are united by self-adhesive forces of the CNFs. Their strength is comparable to those of light-weight structural materials, such as aluminum alloys and glass fiber-reinforced plastics, while the CNF plates are even lighter. The plates feature excellent flame self-extinguishing properties due to the carboxylate structure of CNFs and further show anisotropic thermal conduction between the in-plane and out-of-plane directions. A strategy for overcoming the high water absorption, a major issue of CNF materials, through the counterion design of carboxy groups is also demonstrated.

Synthesis and oxidative transformations of 2-functionalized 2-trifluoromethyltetrahydrothiophenes

2-Acetoxymethyl- and 2-hydroxymethyl-2-(trifluoromethyl)tetrahydrothiophenes have been prepared from readily obtainable 3-hydroxy-3-(trifluoromethyl)tetrahydropyran by its reactions of sulfur-assisted ring contraction. With the aim to explore the synthetic utility of new fluorinated tetrahydrothiophenes and to estimate the influence of trifluoromethyl group on their reactivity, various types of the oxidative transformations, involving oxidation and oxoimination of sulfur atom, oxidation of hydroxymethyl group and chlorination of free α-position to sulfur atom, were studied. Large sterical demand of CF3 group has been revealed from the stereochemical outcome of the oxidation and oxoimination of the sulfur atom. Electron withdrawing properties of CF3 group are evident from low susceptibility of 2-hydroxymethyl-(trifluoromethyl)tetrahydrothiophene to the oxidation of hydroxymethyl group and from low activity of 2-acetoxymethyl-5-chloro-2-(trifluoromethyl)tetrahydrothiophene in nucleophilic substitution and dehydrochlorination reactions. Convenient protocols for the preparation of trifluoromethylated tetrahydrothiophenes with sulfoxide, sulfone, sulfoximino, aldehyde and carboxy functionalities, acetoxy group in the position 5 of the heterocycle, and 2-(acetoxymethyl)-2-(trifluoromethyl)-2,3-dihydrothiophene have been developed. The results of these studies demonstrate that 2-acetoxymethyl- and 2-hydroxymethyl-2-(trifluoromethyl)tetrahydrothiophenes are useful precursors to a variety of new small fluorinated molecules.

Discrete Stacked Dimers of Aromatic Oligoamide Helices.

Tight binding was observed between the C‐terminal cross section of aromatic oligoamide helices in aqueous solution, leading to the formation of discrete head‐to‐head dimers in slow exchange on the NMR timescale with the corresponding monomers. The nature and structure of the dimers was evidenced by 2D NOESY and DOSY spectroscopy, mass spectrometry and X‐ray crystallography. The binding interface involves a large hydrophobic aromatic surface and hydrogen bonding. Dimerization requires that helices have the same handedness and the presence of a C‐terminal carboxy function. The protonation state of the carboxy group plays a crucial role, resulting in pH dependence of the association. Dimerization is also influenced by neighboring side chains and can be programmed to selectively produce heteromeric aggregates.

Diskrete gestapelte Dimere von aromatischen Oligoamid‐Helices

AbstractEine starke Bindung wurde zwischen den C‐terminalen Querschnitten von aromatischen Oligoamid‐Helices in wässriger Lösung beobachtet. Diese führt zur Bildung von diskreten Kopf‐an‐Kopf‐Dimeren, die im langsamen Austausch mit den entsprechenden Monomeren auf der NMR‐Zeitskala stehen. Die Art und Struktur der Dimere wurde durch 2D‐NOESY‐ und DOSY‐Spektroskopie, Massenspektrometrie und Röntgenkristallographie nachgewiesen. An der Bindungsschnittstelle beteiligt sind eine große hydrophobe aromatische Oberfläche und Wasserstoffbrückenbindungen. Die Dimerisierung setzt voraus, dass die Helices die gleiche Händigkeit aufweisen und eine C‐terminale Carboxyfunktion vorhanden ist. Der Protonierungszustand der Carboxygruppe spielt eine entscheidende Rolle und führt zu einer pH‐Abhängigkeit der Assoziation. Die Dimerisierung wird auch durch benachbarte Seitenketten beeinflusst und kann programmiert werden, um selektiv heteromere Aggregate zu bilden.

Poly(carboxyethyl acrylate‐co‐ethylene glycol dimethacrylate) precursor monolith with bonded octadecyl ligands for use in reversed‐phase capillary electrochromatography

A carboxy precursor monolithic column, namely poly(carboxy ethyl acrylate-co-ethylene glycol dimethacrylate) was first produced in a 100μm i.d. fused-silica capillary and subsequently surface bonded with n-octadecyl (C18 ) ligands by a post-polymerization functionalization process with octadecylamine in the presence of N,N´-dicyclohexylcarbodiimide. The bonding of octadecyl ligands was achieved via an amide linkage between the carboxy functions of the precursor monolith and the amino group of the octadecylamine compound. The resulting C18 monolith exhibited a very low electroosmotic flow (EOF), a fact that required the incorporation of small amounts of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) in the polymerization solution to produce a precursor monolith with fixed negative charges of sulfonate groups. This may indicate that the conjugation of the carboxy functions with octadecylamine occurred to a large extent so that the amount of residual carboxy functions was sparsely dispersed and not enough to produce a desirable EOF. The EOF velocity of the C18 column having fixed negative charges provided by the incorporated AMPS increased with increasing ACN content of the mobile phase signaling an increased binding of mobile phase ions to the polar amide linkages near the monolithic surface, and a decreased viscosity of the mobile phase, both of which would result in increased EOF velocity. The C18 monolithic column constituted a novel nonpolar sorbent for reversed-phase capillary electrochromatography for nonpolar solutes, e.g., alkylbenzenes, alkylphenyl ketones, and polyaromatic hydrocarbons, and slightly polar compounds including phenol and chlorophenols. The C18 monolithic column exhibited relatively high selectivity toward chlorophenols differing by one chloro substituent.

Synthesis of 13 C-labelled ω-hydroxy carboxylic acids of the general formula HO213 C-(CH2 )n -CH2 OH or HO2 C-(CH2 )n -13 CH2 OH (n = 12, 16, 20, 28).

13 C-labelled ω-hydroxy-carboxylic acids HO213 C-(CH2 )n -CH2 OH or HO2 C-(CH2 )n -13 CH2 OH (n = 12, 16, 20, 28) with 13 C labels selectively introduced either at the carboxy group or at the primary alcohol function at the end of the hydrocarbon chain have been synthesized. Different synthetic strategies had to be applied depending on the position of the label, the chain length of the respective synthetic target and due to economic considerations. 13 C labels in general were introduced by nucleophilic substitution of a suitable leaving group with labelled potassium cyanide and subsequent hydrolysis of the nitriles to produce the corresponding labelled carboxy functions, which may also be reduced to give the labelled primary alcohol group. All new compounds are characterized by GC/MS, IR and NMR methods as well as by elemental analysis.

Core‐Shell Functionalized Zirconium‐Pemetrexed Coordination Nanoparticles as Carriers with a High Drug Content

AbstractSelected drug molecules with Lewis base functions can be assembled into coordinative nanoparticles (NPs) by linking them with suitable metal ions. Such nanomaterials exhibit a high material economy due to high drug contents and minor amounts of inactive additives. The antifolate pemetrexed (PMX) which is used for the treatment of lung cancers contains two carboxy functions that are able to undergo coordinative binding of metal ions. This study presents the development of a multilayer PMX NP system where each layer serves a distinct purpose. The metal‐drug NP core is assembled in a bottom‐up approach by coordinative interactions between zirconium (IV) ions and PMX molecules. Since the NP core is generated from drug molecules as essential units, it features a very high drug content of almost 80%. The NP core is stabilized against serum with a shell of a polymerized oligoamine‐modified trimethoxysilane derivative (TMSP). As external layer, a polyglutamate‐block‐polysarcosine‐N3 (pGlu‐b‐pSar) coating mediates efficient colloidal stabilization and enables introduction of targeting functionalities by click chemistry. Attaching folate or transferrin ligands to the polymer layer enhances NP uptake into target receptor positive KB and L1210 cells. This study illustrates the development and characterization of metal‐drug coordination NPs with high drug content and variable external functionalizations.

SELECTION OF PROTECTIVE GROUPS UPON OPTIMIZING THE SYNTHESIS OF γ-PNA BASED ON L-GLU

This work is devoted to optimization of the synthesis of γ-S-carboxyethyl monomers of PNA based on L-Glu. PNA are promising compounds that hybridize with DNA or RNA, and due to their properties they are used in molecular biology, personalized medicine, and can also be used to create nanomaterials. To increase the yield of the desired monomers, it has been proposed to replace the benzyl protecting group with the carboxy function of the side radical by cyclohexyl one. Two synthetic schemes were proposed. In the first of them, γ-benzyl-N-Boc-glutamic acid, which was reduced to β-amino alcohol, was the starting compound. The hydroxyl group was protected by a dimethyl-tert-butylsilyl group. The benzyl ester in the side radical was cleaved by reduction on a palladium catalyst using ammonium formate. However, the subsequent acylation of cyclohexyl alcohol failed. In the second of the proposed schemes, a known sequence of reactions was used, which led to the formation of a cyclic derivative of Cbz-protected glutamic acid. Then, the resulting compound was acylated with cyclohexyl alcohol to give the desired ester. The subsequent transformation of the protective groups of the ester resulted in the diprotected L-glutamic acid in three stages. Subsequent reduction gave the desired protected β-amino alcohol containing a cyclohexyl protecting group in the side radical. This compound was further used in the Mitsunobu reaction to obtain a completely protected core of the PNA monomer. Subsequent thiolysis reaction resulted in the formation of the target secondary amine, the stability of which substantially exceeded the stability of its analog with benzyl protection, obtained and investigated before. The structure of the new compounds obtained is confirmed by 1H-NMR spectroscopy.

Synthesis of functionalized pyrazole derivatives by regioselective [3+2] cycloadditions ofN-Boc-α-amino acid-derived ynones

Abstract[3+2] cycloadditions of ynones derived from glycine and (S)-alanine and some other dipolarophiles with azomethine imines, nitrile oxides, diazoacetate, and azidoacetate were studied. The dipolarophiles were obtained fromα-amino acids, either by the reduction of the carboxy function with ethynylmagnesium bromide or by propiolation of the amino function. Cu-catalyzed cycloadditions of ynones to azomethine imines were regioselective and gave the expected cycloadducts as inseparable mixtures of diastereomers. In some instances, further oxidative hydrolytic ring-opening took place to afford 3,3-dimethyl-3-(1H-pyrazol-1-yl)propanoic acids. Acid-catalyzed cycloadditions of 3-butenone were also regioselective and provided mixtures of diastereomeric cycloadducts, which were separated by chromatography. In the reactions of title ynones with alkyl diazoacetates,in situ-formed benzonitrile oxides, andtert-butyl azidoacetate, all cycloadducts were obtained as single regioisomers. The structures of all novel compounds were established by nuclear magnetic resonance and X-ray diffraction.

Allene Oxide Synthase Pathway in Cereal Roots: Detection of Novel Oxylipin Graminoxins.

Young roots of wheat, barley, and sorghum, as well as methyl jasmonate pretreated rice seedlings, undergo an unprecedented allene oxide synthase pathway targeted to previously unknown oxylipins 1–3. These Favorskii‐type products, (4Z)‐2‐pentyl‐4‐tridecene‐1,13‐dioic acid (1), (2′Z)‐2‐(2′‐octenyl)‐decane‐1,10‐dioic acid (2), and (2′Z,5′Z)‐2‐(2′,5′‐octadienyl)‐decane‐1,10‐dioic acid (3), have a carboxy function at the side chain, as revealed by their MS and NMR spectral data. Compounds 1–3 were the major oxylipins detected, along with the related α‐ketols. Products 1–3 were biosynthesized from (9Z,11E,13S)‐13‐hydroperoxy‐9,11‐octadecadienoic acid, (9S,10E,12Z)‐9‐hydroperoxy‐10,12‐octadecadienoic acid (9‐HPOD), and (9S,10E,12Z,15Z)‐9‐hydroperoxy‐10,12,15‐octadecatrienoic acid, respectively, via the corresponding allene oxides and cyclopropanones. The data indicate that conversion of the allene oxide into the cyclopropanone is controlled by soluble cyclase. The short‐lived cyclopropanones are hydrolyzed to products 1–3. The collective name “graminoxins” has been ascribed to oxylipins 1–3.

Selectivity in domino reaction of ortho-carbonyl azides with malononitrile dimer leading to [1,2,3]triazolo[1,5-a]pyrimidines

The selectivity of the domino reaction of the (het)aryl azides, containing the carbonyl center in the ortho position to the azido group, with malonodinitrile dimer was studied. It has been shown that in the case of aromatic azides bearing a carboxy or nitrile function in the ortho position, the reaction occurred with the formation of exclusively [1,2,3]triazolo[1,5-a]pyrimidine instead of [1,2,3]triazolo[4,5-b]pyridine system. Thus, new [1,2,3]triazolo[1,5-a]quinazolines, thieno[2,3-e][1,2,3]triazolo[1,5-a]pyrimidine, and thieno[3,2-e][1,2,3]triazolo[1,5-a]-pyrimidines, having polyfunctional 1-amino-2,2-dicyanovinyl fragment, were prepared in short time in high yields.

Unexpected reactivity of the 2′-carboxyl functionality in rhodamine dyes

Contrary to previous literature reports, the reactivity of the 2′ carboxylic acid in rhodamine dyes was found to be much more reactive than anticipated. Typically, the 4′- or 5′-carboxy functionality in dicaboxyrhodamines is targeted for bioconjugation use due to the supposed unreactivity of the 2′ carboxylic acid. Reactive esters of 2′-carboxyrhodamine dyes lacking the 4′(5′)-carboxy substitutions permit a simplified synthesis of single isomer dyes but possess similar reactivities useful for labeling studies.

ChemInform Abstract: Regioselective Decarboxylative Cross‐Coupling of Carboxy Isoquinoline N‐Oxides.

ChemInformVolume 46, Issue 43 Heterocyclic Compounds ChemInform Abstract: Regioselective Decarboxylative Cross-Coupling of Carboxy Isoquinoline N-Oxides. Jean-Baptiste E. Y. Rouchet, Jean-Baptiste E. Y. Rouchet INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorCedric Schneider, Cedric Schneider INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorCorinne Fruit, Corinne Fruit INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorChristophe Hoarau, Christophe Hoarau INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this author Jean-Baptiste E. Y. Rouchet, Jean-Baptiste E. Y. Rouchet INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorCedric Schneider, Cedric Schneider INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorCorinne Fruit, Corinne Fruit INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this authorChristophe Hoarau, Christophe Hoarau INSA Rouen, CNRS, Univ. Normandie, F-76821 Mont-Saint-Aignan, Fr.Search for more papers by this author First published: 08 October 2015 https://doi.org/10.1002/chin.201543163Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume46, Issue43October, 2015 RelatedInformation

Regioselective decarboxylative cross-coupling of carboxy isoquinoline N-oxides.

A straightforward method for direct decarboxylative arylation of 1- and 3-carboxy isoquinaldic acid N-oxides with aryl iodides is reported. The reaction proceeded selectively at the carboxy function site to exclusively give the corresponding C-1 or C-3 arylated product. This methodology tolerates various aryl iodides substituted by electronically different groups. Combined with subsequent Reissert-Henze chlorination and SNAr amination, the decarboxylative arylation provides an efficient access to 1,3-functionalized isoquinoline-based antitumor agent.

Electrochemical characterization of a responsive macromolecular interface on gold

This study reports on the investigation of a thermo­responsive polymer as a thin film on electrodes and the influence of coupling a peptide and an antibody to the film. The utilized polymer from the class of poly(oligoethylene glycol)‐methacrylate polymers (poly(OEGMA)) with carboxy functions containing side chains was synthesized and properly characterized in aqueous solutions. The dependence of the cloud point on the pH of the surrounding media is discussed. The responsive polymer was immobilized on gold electrodes as shown by electrochemical, quartz crystal microbalance (QCM), and atomic force microscopy (AFM) techniques. The temperature dependent behavior of the polymer covalently grafted to gold substrates is investigated using cyclic voltammetry (CV) in ferro‐/ferricyanide solution. Significant changes in the slope of the temperature‐de­pendence of the voltammetric peak current and the peak separation values clearly indicate the thermally induced conformational change on the surface. Finally, a bio­recognition reaction between a short FLAG peptide (N‐Asp‐Tyr‐Lys‐Asp‐Asp‐Asp‐Asp‐Lys‐C) covalently im­mobilized on the polymer interface and the corresponding IgG antibody was performed. The study shows that the responsiveness of the electrode is retained after peptide coupling and antibody binding, although the response is diminished.

Regioselective synthesis of 1- and 4-substituted 7-oxopyrazolo[1,5-a]pyrimidine-3-carboxamides

The synthesis of 7-substituted pyrazolo[1,5-a]pyrimidine-3-carboxamides was studied. First, methyl 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (5) was prepared in three steps from methyl 5-amino-1H-pyrazole-4-carboxylate (3). Treatment of 5 with POCl3 gave the highly reactive 7-chloro derivative 10, which was reacted with amines, benzyl alcohol, and phenylboronic acid in the presence of Pd-catalyst to give the corresponding 7-substituted derivatives 11. Hydrolysis of the esters 5 and 11 followed by amidation gave the corresponding carboxamides 16a–h and 15. Regioselectivity of N-alkylation of 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid derivatives 5 and 16 was tunable by the carboxy function. Alkylation of the secondary amides 16a–f furnished the 1-alkyl derivatives 17a–f, whereas the ester 5 and the tertiary amides 16g,h gave the 4-alkyl derivatives 14a–d and 16m,n, selectively.

Carboxy-Telechelic Polyolefins in Cross-Linked Elastomers

We demonstrate that ring-opening metathesis copolymerization of 3-hexyl-cis-cyclooctene and cis-cyclooctene in the presence of maleic acid as a chain transfer agent leads to precise control over the molar mass, branching and crystallinity of the resulting carboxy-telechelic polyalkenamers. Subsequent hydrogenation using a silica-supported platinum catalyst had a negligible effect on the carboxy functionality and led to telechelic polyolefins with high thermal resistance, low glass transition temperatures (<−57 °C), little to no crystallinity, and viscosities similar to those of liquid silicon rubber prior to cross-linking. These properties are ideal for easily processable reactive polyolefin prepolymers that can be readily cured to form elastomers. We demonstrate that a fast and controlled curing process can be achieved in the presence of polyfunctional aziridines. The properties of the thermoset elastomer products were evaluated by tensile, differential scanning calorimetry, and dynamic mechanical analyses.

Synthesis, characterisation and some chemistry of C- and B-substituted carboxylic acids of cobalt bis(dicarbollide)

Low temperature reactions of lithiated cobalt bis(1,2-dicarbollide)(1-) (1⁻) in DME with carbon dioxide leads to the substitution of 1⁻ at the C-atoms by carboxy function(s). This results in a good yield formation of monosubstituted and disubstituted products of formulations [(1-HOOC-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co)](-) (2⁻) and [(HOOC)2-(1,2-C2B9H10)2-3,3'-Co](-) (3a,b⁻), respectively. Indeed, the latter compound is in fact a mixture of two diastereoisomers, denoted here as 1,1'-anti (3a⁻) and 1,2'-syn-isomer (3b⁻), from which only the former major species (3a⁻) could be isolated in pure form. Considerations about stereochemistry of these species are supported by geometry optimizations and calculations of (11)B NMR shifts at the GIAO-DFT level. In addition, three monocarboxylic acids with three different linear spacers between the carboxy groups and the cage are reported. The first one of the formula [(1-HOOC-CH2-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co](-) (5⁻) results in a lithiation followed by reaction with BrCH2COOEt and hydrolysis of the respective ethyl ester (4⁻). Another one with ethylene chain [(1-HOOC-(CH2)2-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co](-) (6⁻) was prepared by the oxidation of a hydroxypropyl derivative of the ion 1⁻. The sole representative of B-substituted species of the formulation [8-(HOOC-CH2-O-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co](-) (7⁻) is prepared by alkylation of the known 8-hydroxy derivatives of the ion 1⁻ by BrCH2COOEt and alkaline hydrolysis. A synthetic route to active nitrofenyl esters (8⁻, 9⁻ and 10⁻) is described here based on the respective acids 5⁻ to 7⁻. As verified, the nitrophenyl esters provide easy access to the formation of amidic bonds between the boron cage and organic primary amino functions. Examples of compounds containing butylamide or benzylamide [(1-RNHOC-(CH2)n-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co](-) (n = 1,2; R = Bu 11a,b⁻, R = Bn: 12a,b⁻) end group are described. Also the possibility of inter-connecting two clusters of the anion 1⁻ via the amidic bond is shown in derivative (13⁻). These methods are applicable in the synthesis of a variety of functional molecules, particularly those applicable in drug design, surface modifications, and material science.