Antipodal and vicinal shift effects in 11B, 13C, and 1H NMR spectra of substituted dicarba-closo-dodecarboranes(12)

Heřmánek, S.; Gregor, V.; Štı́br, Bohumil; Plešek, Jaromı́r; Janoušek, Zbyněk; Antonovich, V. A.

doi:10.1135/cccc19761492

Cited by 41 publications

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“…The isolated derivatives include zwitterionic I-L-I-CBlt Htl (L = H3N and (CH3hS) and 12-L-I-CB tt Htl (L = (CH3)2S and CH 3 SCH 2 SCH 3 ) compounds along with C-substituted derivatives of the general formula [I-X-CBII HI tl-(X = HOOC, HO, CH 3 0, HS and CH 3 S).Direct halogenation of [1-CB II H I2 1-produces [7,8,9,1O,12-CI s -I-CB II H 7 1-, [7,8,9,10,11,12--X6-I-CBIIH61-(X = CI, Br), [12-1-CB II H I tl-and [7,12-I 2 +CB II H I0 1-substituted species. Constitution of all produ(ts was established by t H, liB, IR and mass spectrometry and is supported by some chemical reactions of the compounds.…”

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confidence: 98%

“…Direct halogenation of [1-CB II H I2 1-produces [7,8,9,1O,12-CI s -I-CB II H 7 1-, [7,8,9,10,11,12--X6-I-CBIIH61-(X = CI, Br), [12-1-CB II H I tl-and [7,12-I 2 +CB II H I0 1-substituted species. Constitution of all produ(ts was established by t H, liB, IR and mass spectrometry and is supported by some chemical reactions of the compounds.…”

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confidence: 99%

“…Chlorination of I in acetic acid at ambient temperature with excess chlorine leads to [7,8,9,1O, -(Ii) whereas at 100°C the hexachloro derivative [7,8,9,lO,1l,12-CI 6 -1-CB ll H 6 ]-(Ij) is obtained. With excess bromine in acetic acid at 80°C, only the hexabromo derivative [7,8,9,10,11, …”

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Chemistry of compounds with the 1-carba-closo-dodecaborane(12) framework

Jelı́nek

Plešek

Heřmánek

et al. 1986

Collect. Czech. Chem. Commun.

147

159

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Synthesis of various compounds containing the l-carba-c1oso-dodecaborane cage is reported. The isolated derivatives include zwitterionic I-L-I-CBlt Htl (L = H3N and (CH3hS) and 12-L-I-CB tt Htl (L = (CH3)2S and CH 3 SCH 2 SCH 3 ) compounds along with C-substituted derivatives of the general formula [I-X-CBII HI tl-(X = HOOC, HO, CH 3 0, HS and CH 3 S).Direct halogenation of [1-CB II H I2 1-produces [7,8,9,1O,12-CI s -I-CB II H 7 1-, [7,8,9,10,11,12--X6-I-CBIIH61-(X = CI, Br), [12-1-CB II H I tl-and [7,12-I 2 +CB II H I0 1-substituted species. Constitution of all produ(ts was established by t H, liB, IR and mass spectrometry and is supported by some chemical reactions of the compounds.The [1-CBl.lH12]-anion (I) was first isolated in 1967 by Knoth!, who later 2 improved the synthesis and made initial attempts at substitution, impure samples of B-bromo and 1-(CH 3 hSi-derivatives being the only products. We have recently found a more convenient route 3 .4 to the parent anion I and to some of its uncharged l-L-I-CBllHll (II) (L = CH3NH 2, (CH3)2NH and (CH3hN) congeners. We wish to report in this paper some other possibilities of synthetizing a series of new substituted derivatives in this area of borane chemistry.Several new derivatives of the anion I and its zwitterionic analogues II can be obtained either from the relevant 7-substituted 7-carba-nido-undecaboranes, 7-L-7--CBlOHI2 (III), by inserting the missing boron vertex or by modifying the present exoskeletal functional group in the compounds of the type II.If 7-H3N-7-CBlOHI2 (IlIa) is treated with sodium tetrahydroborate followed by prolonged heating with triethylamine borane at 200°C and the intermediate product is then hydrolyzed with hydrochloric acid, l-amine-l-carba-closo-dodecaborane(ll), I-H3N-I-CBuHu (lIa), can be obtained in good yield as the parent compound of the loN-substituted species. Its N-monomethylderivative lIb is available from the N,N-dimethyl derivative 3 lIe by a curious demethylation with iodine 4 and the N,N,N-trimethyl derivative lId results from successive methylation of any of compounds 11 a-e. Derivatives II a -e behave as weak N-acids with pK" values 6'0, 6'5, and 5'7, respectively (50% ethanol), giving rise to anions [1-H 2N-I-CB IIH II] -(Ia). [1-CH3NH-I-CB1.1HII]-(Ib)4 and [1-(CH3)2N-I-CBtIHu]-(Ie)3.

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confidence: 98%

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Chemistry of compounds with the 1-carba-closo-dodecaborane(12) framework

Jelı́nek

Plešek

Heřmánek

et al. 1986

Collect. Czech. Chem. Commun.

147

159

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“…The para position permits additional examination of Heřmánek's 16 antipodal effect [17][18][19][20] [closo-1-CB 9 H 10 ] -Anion and New C-Substituted Derivatives Fig. 1 summarize the shift increments (∆δ) in 11 B NMR and 13 C NMR of the halogenated and methylated derivatives 3a-3e and compares them with the C-halogenated [closo-1-CB 11 H 12 ] -anions.…”

Section: Nmr Spectramentioning

confidence: 99%

Improved synthesis of [closo-1-CB9H10]– anion and new C-substituted derivatives

Ringstrand

Bateman

Shoemaker

et al. 2009

Collect. Czech. Chem. Commun.

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Dedicated to Professor Jaromír Plešek on the occasion of his 80th birthday in recognition of his major contributions to cluster borane chemistry.The Brellochs method was utilized to gain access to the [closo-1-CB 9 H 10 ] -anion (1). Previous work describing the details of the synthesis of 1 via the [closo-2-CB 9 H 10 ] -anion (2) was brief and insufficient. Therefore, we report an optimized procedure for the synthesis of 1, the preparation of the unknown C-halogenated series using N-halosuccinimides and bis(benzenesulfonyl)fluoroamine, and the unknown C-methylated product using CH 3 I. NMR properties and regularities within the series were also investigated.Monocarbaborane anion [CB 9 H 10 ] -(1) 1 belongs to the group of anions of general formula [CB n H n+1 ] -, where the anionic charge is highly delocalized. These anions possess chemical, electrochemical and thermal stability; thus, they are useful in weakly coordinating and low-nucleophilic anion chemistry as were described by Reed and Strauss 2 . Out of this group, the [closo-1-CB 11 H 12 ] -anion is the most studied 3 because of its easy accessibility. However, new synthetic breakthroughs produced monocarbaboranes via Brellochs reactions 4-6 of aldehydes with nido-B 10 H 14 , starting an accelerated expansion in sub-icosahedral monocarbaborane chemistry and revealing compounds with highly desirable characteristics.

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“…As expected, the presence of the positively charged SMe 2 group bonded to the B8 atom leads to a shift in all resonances, except that at d = À5.4 ppm, of approximately 3 ppm to lower field with respect to the corresponding ones in commo-[3,3'-Co(1,2-C 2 B 9 H 11 ) 2 ]. [23] The UV-visible spectral data for 2-Cl in acetonitrile are displayed in Table 1, and consist of four absorptions at 215, 250, 300 and 464 nm. To our knowledge, the only cationic cobaltacarborane sandwich reported in the literature is the highly sensitive complex commo-[3,3'-Co{4-(4''-(C 5 H 4 N)CO 2 CH 3 )-1,2-C 2 B 9 H 10 } 2 ]…”

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Highly Stable Neutral and Positively Charged Dicarbollide Sandwich Complexes

Núñez

Tutusaus

Teixidor

et al. 2005

Chemistry A European J

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Novel sandwich metallacarboranes commo-[3,3'-Ni(8-SMe2-1,2-C2B9H10)2] (1), commo-[3,3'-Co(8-SMe2-1,2-C2B9H10)2]+ (2+), commo-[3,3'-Ru(8-SMe2-1,2-C2B9H10)2] (4) and commo-[3,3'-Fe(8-SMe2-1,2-C2B9H10)2] (5) have been prepared by reaction of [10-SMe2-7,8-nido-C2B9H10]- with NiCl2 x 6 H2O, CoCl2, [RuCl2(dmso)4] and [FeCl2(dppe)], respectively. Reduction of 2+ with metallic Zn leads to the neutral and isolable complex commo-[3,3'-Co(8-SMe2-1,2-C2B9H10)2] (3). Theoretical calculations using the ZINDO/1 semiempirical method show three energy minima for complexes 1-3 and 5 that agree with the presence of three different rotamers in solution at low temperature, while four relative energy minima have been found for 4. The calculated rotational energy barriers for complexes 1-5 have been found in the range 5.2+/-0.2 and 11.5+/-0.2 kcal mol(-1). These values are in agreement with the experimental data calculated for complexes 2+ and 5. Only one rotamer is found in the X-ray crystal structure of complexes 1-3, while two are observed for 4. Neutral complexes 1, 3 and 4 exhibit a gauche conformation, whereas a cisoid conformation is found for the 2+ ion. Rotamers evident from X-ray diffraction studies are in agreement with the global energy minimum calculated by the ZINDO/1 method. The electrochemical studies conducted on 1, 3, 4 and 5 support the proposal that the charge-compensated ligand [10-SMe2-7,8-nido-C2B9H10]- stabilises lower oxidation states in metals than the dianionic [7,8-nido-C2B9H11]2- and even the [C5H5]- ligands.

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Antipodal and vicinal shift effects in 11B, 13C, and 1H NMR spectra of substituted dicarba-closo-dodecarboranes(12)

Cited by 41 publications

References 0 publications

Chemistry of compounds with the 1-carba-closo-dodecaborane(12) framework

Chemistry of compounds with the 1-carba-closo-dodecaborane(12) framework

Improved synthesis of [closo-1-CB9H10]– anion and new C-substituted derivatives

Highly Stable Neutral and Positively Charged Dicarbollide Sandwich Complexes

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