Borane Carbonyl Research Articles

Analysis of Some Elements and Speciated Compounds in Fish Found in the New Calabar River of the Niger Delta Area, Nigeria

The flesh of guinean and blackchin tilapia, and mullet found in Choba river were collected for elemental studies of mercury, cadmium, lead, arsenic, nickel and speciated forms. Analytical method of X-ray fluorescence (XRF) was used for the elemental studies while Gas chromatographymass spectrometer (GC-MS) was used for the speciated forms. 4.3 mg/kg was the highest concentration of cadmium observed in blackchin tilapia. The three fish species all contained about 0.5 mg/kg of arsenic and 1 mg/kg of mercury. 1.7 mg/kg of lead was detected in mullet while 7.3 mg/kg of nickel was detected in blackchin tilapia. Organometallic compounds found were nickel tetracarbonyl, borane carbonyl in guinean tilapia, nickel tetracarbonyl, borane carbonyl and germanium(iv) pthalocyanine dichloride in blackchin tilapia and [µ-(ƞ6-benzene)] bis (ƞ5-2,4-cyclopentadien-yl) diµ-hydrodi-vanadium. Borane carbonyl was found in mullet.

Elucidation of the CO-Release Kinetics of CORM-A1 by Means of Vibrational Spectroscopy.

CO-releasing molecules (CORMs) are developed for investigations of the interaction between the signaling molecule carbon monoxide (CO) and cells or tissue. Prior to their application these molecules must be fully characterized with respect to their CO-release mechanism. One widely used CORM for biological application is sodium boranocarbonate (CORM-A1), which shows pH-dependent CO liberation. The complete reaction mechanism of CORM-A1 is not fully understood yet. Therefore, in this contribution time-resolved gas-phase IR spectroscopy is used to monitor the headspace above decaying CORM-A1 solutions at four different pH values (5.8 to 7.4). Borane carbonyl is found as an intermediate in the gas phase, which is formed during CORM degradation and further decays to CO. Concentration profiles of a pseudoconsecutive first-order reaction are successfully fitted to specific band areas of the measured gas-phase spectra, and the rate constants are obtained. The production of borane carbonyl is strongly pH dependent (half-lives between 5 and 106 min), whereas the decay of borane carbonyl in the gas phase is nearly constant with a half-life of about 33 min. The ratio of liberated CO molecules per CORM-A1 is determined to be 0.91±0.09, and boric acid is identified as further end product.

ChemInform Abstract: Carbonylation Reactions of Intramolecular Vicinal Frustrated Phosphane/Borane Lewis Pairs.

The intramolecular frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 4 adds cooperatively to carbon monoxide to form the five-membered heterocyclic carbonyl compound 5. The intramolecular FLP 7 contains an exo-3-B(C6F5)2 Lewis acid and an endo-2-PMes2 Lewis base functionality coordinated at the norbornane framework. This noninteracting FLP adds carbon monoxide in solution at -35 °C cooperatively to yield a five-membered heterocyclic FLP-carbonyl compound 8. In contrast, FLP 7 is carbonylated in a CO-doped argon matrix at 25 K to selectively form a borane carbonyl 9 without involvement of the adjacent phosphanyl moiety. The free FLP 7 was generated in the gas phase from its FLPH2 product 10. A DFT study has shown that the phosphonium hydrido borate zwitterion 10 is formed exergonically in solution but tends to lose H2 when brought into the gas phase.

Formylborane Formation with Frustrated Lewis Pair Templates

Boranes R2 BH react with carbon monoxide by forming the respective borane carbonyl compounds R2 BH(CO). The formation of (C6 F5 )2 BH(CO) derived from the Piers borane, HB(C6 F5 )2 , is a typical example. Subsequent CO-hydroboration does not take place, since the formation of the formylborane is usually endothermic. However, an "η(2) -formylborane" was formed by CO-hydroboration with the Piers borane at vicinal phosphane/borane frustrated Lewis pair (FLP) templates. Subsequent treatment with pyridine liberated the intact formylborane from the FLP framework, and (pyridine)(C6 F5 )2 BCHO was then isolated as a stable compound. This product underwent typical reactions of carbonyl compounds, such as Wittig olefination.

Formylborane Formation with Frustrated Lewis Pair Templates

AbstractBoranes R2BH react with carbon monoxide by forming the respective borane carbonyl compounds R2BH(CO). The formation of (C6F5)2BH(CO) derived from the Piers borane, HB(C6F5)2, is a typical example. Subsequent CO‐hydroboration does not take place, since the formation of the formylborane is usually endothermic. However, an “η2‐formylborane” was formed by CO‐hydroboration with the Piers borane at vicinal phosphane/borane frustrated Lewis pair (FLP) templates. Subsequent treatment with pyridine liberated the intact formylborane from the FLP framework, and (pyridine)(C6F5)2BCHO was then isolated as a stable compound. This product underwent typical reactions of carbonyl compounds, such as Wittig olefination.

Carbonylation Reactions of Intramolecular Vicinal Frustrated Phosphane/Borane Lewis Pairs

The intramolecular frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 4 adds cooperatively to carbon monoxide to form the five-membered heterocyclic carbonyl compound 5. The intramolecular FLP 7 contains an exo-3-B(C6F5)2 Lewis acid and an endo-2-PMes2 Lewis base functionality coordinated at the norbornane framework. This noninteracting FLP adds carbon monoxide in solution at -35 °C cooperatively to yield a five-membered heterocyclic FLP-carbonyl compound 8. In contrast, FLP 7 is carbonylated in a CO-doped argon matrix at 25 K to selectively form a borane carbonyl 9 without involvement of the adjacent phosphanyl moiety. The free FLP 7 was generated in the gas phase from its FLPH2 product 10. A DFT study has shown that the phosphonium hydrido borate zwitterion 10 is formed exergonically in solution but tends to lose H2 when brought into the gas phase.

Syntheses and Characterization of (C2F5)3BCO and (C3F7)3BCO

The new tris(perfluoroalkyl)borane carbonyls, (C(2)F(5))(3)BCO and (C(3)F(7))(3)BCO, were prepared by means of a novel synthetic route using commercially available precursors by reacting K[(C(2)F(5))(3)BCOOH] and K[(C(3)F(7))(3)BCOOH] with concentrated sulfuric acid in the last step. The carboxylic acids, K[(C(2)F(5))(3)BCOOH] and K[(C(3)F(7))(3)BCOOH], were prepared by oxidative cleavage of the C[triple bond]C triple bonds in Cs[(C(2)F(5))(3)BC[triple bond]CPh] and Cs[(C(3)F(7))(3)BC[triple bond]CPh] in a two-step process to yield K[(C(2)F(5))(3)BCO-COPh] and K[(C(3)F(7))(3)BCO-COPh] as isolable intermediates. Crystal structures were obtained of K[(C(2)F(5))(3)BCO-COPh], K[(C(2)F(5))(3)BCOOH].H(2)O, (C(2)F(5))(3)BCO, K[(C(3)F(7))(3)BCOOH].2H(2)O, and (C(3)F(7))(3)BCO. In the crystal structures of (C(2)F(5))(3)BCO and (C(3)F(7))(3)BCO the C[triple bond]O bond lengths are 1.109(2) and 1.103(5) A, respectively, which are among the shortest observed to date. Tris(pentafluoroethyl)borane carbonyl and (C(3)F(7))(3)BCO slowly decompose at room temperature to yield CO, difluoroperfluoroalkylboranes and perfluoroalkenes. The decomposition of (C(2)F(5))(3)BCO was found to follow a first-order rate law with E(a)=107 kJ mol(-1).

Trifluoromethylboranes and ‐Borates: New Synthetic Strategies and Applications

The synthesis of salts with the [B(CF(3))(4)](-) anion has been the starting point for new developments in the field of trifluoromethylboron chemistry. In contrast to the previous syntheses of (CF(3))(n)B derivatives (n=1-3), achieved exclusively by CF(3) transfer, the synthesis of the [B(CF(3))(4)](-) anion was accomplished by fluorination of the [B(CN)(4)](-) anion with ClF or ClF(3) in anhydrous HF. Owing to its thermal and chemical stability, [B(CF(3))(4)](-) is an attractive weakly coordinating anion. However, in concentrated sulfuric acid one of the four CF(3) groups is solvolyzed to a CO ligand to yield the neutral borane carbonyl (CF(3))(3)BC[triple bond]O. It has been shown that the borane carbonyl compound is a versatile synthetic building block, and numerous reactions have been investigated. The addition of nucleophiles to the C atom of the CO ligand is favored, and examples for new derivatives are the anions [(CF(3))(3)BC[triple bond]Pnic](-) (Pnic=N, P, As). Under certain conditions, ligand-exchange reactions are also observed, for example, the formation of (CF(3))(3)BN[triple bond]CH. Finally, the borane carbonyl compound is a component of the conjugated Brønsted-Lewis superacid HF/(CF(3))(3)BCO.

Cyano- and Isocyanotris(trifluoromethyl)borates: Syntheses, Spectroscopic Properties, and Solid State Structures of K[(CF3)3BCN] and K[(CF3)3BNC

A two step synthesis to the isocyanotris(trifluoromethyl)borate anion, [(CF3)3BNC]-, and its isomerization to the cyanotris(trifluoromethyl)borate anion, [(CF3)3BCN]-, at temperatures above 150 degrees C are presented. In the first step (CF3)3BNCH was obtained by reacting (CF3)3BCO with hydrogen cyanide followed by deprotonation of the HCN adduct with Li[N(SiMe3)2] in toluene. The thermal behavior of K[(CF3)3BNC] and K[(CF3)3BCN] were investigated by differential scanning calorimetry (DSC), and K[BF4] was identified as a major solid decomposition product. The enthalpy of the isocyanide-cyanide rearrangement, deltaH(iso) = -35 +/- 4 kJ mol(-1), was obtained from DSC measurements, and the activation energy, E(a) = 180 +/- 20 kJ mol(-1), from kinetic measurements. The isomerization was modeled as an intramolecular reaction employing DFT calculations at the B3LYP/6-311+G(d) level of theory yielding a reaction enthalpy of deltaH(iso) = -36.1 kJ mol(-1) and an activation energy of E(a) = 155.7 kJ mol(-1). The solid-state structures of K[(CF3)3BNC] and K[(CF3)3BCN] were determined by single-crystal X-ray diffraction. Both salts are isostructural and crystallize in the orthorhombic space group Pnma (no. 62). In the crystals the borate anions possess C(s) symmetry, while for the energetic minimum C3 symmetry is predicted by DFT calculations. The borate anions have been characterized by IR and Raman spectroscopy as well as by NMR spectroscopy. The assignment of the IR and Raman bands is supported by their calculated wavenumbers and intensities. The spectroscopic and structural properties of both borate anions are compared to the properties of the isoelectronic borane carbonyl (CF3)3BCO and the [B(CF3)4]- anion as well as to those of other related species.

Gas-Phase Reactions between Diborane and Carbon Monoxide: A Theoretical Study

Experimentally, gas-phase reactions between diborane (B2H6) and carbon monoxide (CO) produce borane carbonyl (BH3CO) and a less volatile material. To elucidate the unknown part of the products, we ...

Tris(trifluoromethyl)borane carbonyl, (CF3)3BCO-synthesis, physical, chemical and spectroscopic properties, gas phase, and solid state structure.

Tris(trifluoromethyl)borane carbonyl, (CF(3))(3)BCO, is obtained in high yield by the solvolysis of K[B(CF(3))(4)] in concentrated sulfuric acid. The in situ hydrolysis of a single bonded CF(3) group is found to be a simple, unprecedented route to a new borane carbonyl. The related, thermally unstable borane carbonyl, (C(6)F(5))(3)BCO, is synthesized for comparison purposes by the isolation of (C(6)F(5))(3)B in a matrix of solid CO at 16 K and subsequent evaporation of excess CO at 40 K. The colorless liquid and vapor of (CF(3))(3)BCO decomposes slowly at room temperature. In the gas phase t(1/2) is found to be 45 min. In the presence of a large excess of (13)CO, the carbonyl substituent at boron undergoes exchange, which follows a first-order rate law. Its temperature dependence yields an activation energy (E(A)) of 112 kJ mol(-)(1). Low-pressure flash thermolysis of (CF(3))(3)BCO with subsequent isolation of the products in low-temperature matrixes, indicates a lower thermal stability of the (CF(3))(3)B fragment, than is found for (CF(3))(3)BCO. Toward nucleophiles (CF(3))(3)BCO reacts in two different ways: Depending on the nucleophilicity of the reagent and the stability of the adducts formed, nucleophilic substitution of CO or nucleophilic addition to the C atom of the carbonyl group are observed. A number of examples for both reaction types are presented in an overview. The molecular structure of (CF(3))(3)BCO in the gas phase is obtained by a combined microwave-electron diffraction analysis and in the solid state by single-crystal X-ray diffraction. The molecule possesses C(3) symmetry, since the three CF(3) groups are rotated off the two possible positions required for C(3)(v)() symmetry. All bond parameters, determined in the gas phase or in the solid state, are within their standard deviations in fair agreement, except for internuclear distances most noticeably the B-CO bond lengths, which is 1.69(2) A in the solid state and 1.617(12) A in the gas phase. A corresponding shift of nu(CO) from 2267 cm(-)(1) in the solid state to 2251 cm(-)(1) in the gas phase is noted in the vibrational spectra. The structural and vibrational study is supported by DFT calculations, which provide, in addition to the equilibrium structure, confirmation of experimental vibrational wavenumbers, IR-band intensities, atomic charge distribution, the dipole moment, the B-CO bond energy, and energies for the elimination of CF(2) from (CF(3))(x)()BF(3)(-)(x)(), x = 1-3. In the vibrational analysis 21 of the expected 26 fundamentals are observed experimentally. The (11)B-, (13)C-, and (19)F-NMR data, as well as the structural parameters of (CF(3))(3)BCO, are compared with those of related compounds.

The structures of borane carbonyl compounds B4X6CO (X = F, Cl, Br and I) by gas-phase electron diffraction and ab initio calculationsElectronic supplementary information (ESI) available: least-squares correlation matrix for electron diffraction structure refinement for B(BF2)3CO; tables of geometric parameters for B4X6CO and B2X4 (X = F, Cl, Br and I). See http://www.rsc.org/suppdata/dt/b2/b207192d/

Gas-phase electron diffraction is a powerful technique for structural analysis of molecules in the gas phase, where they are free from packing forces that can occur in crystals. The compound B(BF2)3CO has been studied by gas-phase electron diffraction to compare its structure to that seen in the solid phase by low-temperature X-ray crystallography. Results show the gas-phase structure to be similar to that seen in the crystal. A model with C3 symmetry refined to give a C–O bond length of 115.8 pm and a C–B bond distance of 150.2 pm, which compare to values of 111.7 and 152.2 pm for the solid phase. The family of borane carbonyl compounds B(BX2)3CO (X = F, Cl, Br or I) have all been studied by ab initio calculations to show the effects of halogen substitution and to gauge the effects of electron correlation and basis set on each structure. Compounds X = F, Cl and Br give calculated structures with C3 symmetry in which the boron–halogen bonds lie coplanar with the C–O bond. In the case of X = I, the BI2 groups are twisted by approximately 35° from coplanar at the DFT level as a result of the large steric interactions between iodine atoms.

Synthesis and structures of carbonyl adducts of the boranes B(BX2)3 (X = F, Cl)

The borane carbonyl adduct (Cl2B)3BCO has been prepared and characterised by spectroscopic methods and X-ray crystallography and is compared with the fluorine analogue (F2B)3BCO which has also been structurally characterised by X-ray crystallography.

B3LYP Calculation of Deuterium Quadrupole Coupling Constants in Molecules

The B3LYP/6-31G(df,3p) model for the calculation of deuterium nuclear quadrupole coupling constants (nqcc's) is shown to yield results as accurate as calculations previously performed at the MP4 level of theory. For 25 molecules, ranging from HD and DF to pyridine and fluorobenzene, the rms difference between the B3LYP nqcc's and the experimental nqcc's is 3.2 kHz (2.7%). For benzene, our calculations suggest that the experimental χbband χccof S. Jans-Bürli, M. Oldani, and A. Bauder, 1989.Mol. Phys.,68, 1111–1123) have been incorrectly assigned with respect to inertia axes and should be reversed. For borane carbonyl and nitric acid, it is shown that nqcc calculations using hydrogen bond lengths given by MP2/6-311 + G(d,p) optimizations in combination with the heavy atom experimental structures significantly improve agreement with the experimental nqcc's.

Predictive schemes for the reactivity of borane carbonyl and the stability of carbonyltrihydroborate anions, BH3C(O)X−

The reactivity of borane carbonyl (BH3CO) and its isoelectronic counterpart the acetylium cation (CH3CO+) are compared resulting in the formulation of (carbonyl)trihydroborate anions, BH3C(O)X−, which are isoelectronic and isostructural with organic carbonyls. By analogy with the ease of reduction of organic carbonyl compounds by hydroborate, the relative stability towards self-reduction-oxidation (hydride transfer from boron to carbonyl carbon) in BH3C(O)X− is proposed. The postulated order, with increasing stability is BH3C(O)Cl− < BH3C(O)H− < BH3C(O)R− < BH3C(O)OR− < BH3C(O)NR−2 < BH3C(O)O2−. Experimental results of this study together with known chemistry are shown to be consistent with the proposed order. Further, it is suggested that a similar predictive scheme may be applicable to the chemistry of the amine-carboxyboranes (boron analogues of α-amino acids) and their derivatives.

Accurate binding energies of diborane, borane carbonyl, and borazane determined by many-body perturbation theory

Binding energies including valence-shell electron correlation are obtained from many-body perturbation theory (MBPT) for diborane, borane carbonyl, and borazane. Results are given for basis sets of double zeta quality and for basis sets with polarization functions added on all atoms. The binding energies (-..delta..E) are found to be (respectively) 35, 21, and 30 kcal/mol. Correlation effects account for 48, 62, and 32% of the binding. The size-consistent nature of the MBPT method enables the computation of enthalpies of reaction for four different reactions involving monoborane, diborane, carbon monoxide, and borane carbonyl. When the theoretical values are corrected for vibrational zero-point energies and the experimental data are adjusted for temperature effects, the results agree (within 5%) and thus confirm the set of experimental enthalpies corresponding to ..delta..H (300/sup 0/C) = -34 kcal/mol for the association reaction yielding diborane. The result for the binding energy of borazane constitutes a prediction in the absence of an experimental value.

Potential constants of borane carbonyl

The vibrational spectra of several isotopic species of BH3CO in neon matrices at 10 °K have been observed. A number of combination bands have also been observed, leading to an assignment of most of the fundamental harmonic frequencies of these isotopic species. A least squares normal coordinate treatment, without constraints, has estimated a set of potential constants. We can conclude that the CO bond in BH3CO is slightly stronger than that of free CO. The interaction coordinates suggest that unimolecular dissociation of the B–C bond proceeds initially toward BH−3+CO+ but reverts to BH3+CO before dissociation.

Mass spectrometric and spectroscopic study of the reaction of borane carbonyl and diborane with oxygen and nitrogen atoms

Mass spectrometric and spectroscopic study of the reaction of borane carbonyl and diborane with oxygen and nitrogen atoms

Borine carbonyl. Bonding and properties in the single-determinant approximation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBorine carbonyl. Bonding and properties in the single-determinant approximationW. C. Ermler, F. D. Glasser, and C. W. KernCite this: J. Am. Chem. Soc. 1976, 98, 13, 3799–3807Publication Date (Print):June 1, 1976Publication History Published online1 May 2002Published inissue 1 June 1976https://doi.org/10.1021/ja00429a011RIGHTS & PERMISSIONSArticle Views206Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (942 KB) Get e-Alerts Get e-Alerts

High-resolution infrared spectrum of borine carbonyl: The ν7 perpendicular band of 10BH 3CO at 12 μm

The ν 7 perpendicular band of 10BH 3CO has been recorded with high resolution. A total of 678 transitions have been assigned in a spectral region of about 90 cm −1. Spectroscopic constants for the band have been derived.