Methylation of Boron Vertices of the Cobalt Dicarbollide Anion

Mortimer,; Cb, Knobler; Mf, Hawthorne

doi:10.1021/ic960353s

Cited by 44 publications

(27 citation statements)

References 18 publications

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“…Palladium-catalyzed B ± C cross-coupling reactions on Cs[8-I-3,3'-Co(1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] with Grignard reagents: We were interested in checking whether the cross-coupling methodology that can be successfully used at the antipodal, B9, and/or B12 o-carborane positions [15a,b] of 9,12-I 2 -1,2-C 2 B 10 H 10 and 12-I-1,2-C 2 B 10 H 11 , at the B3 vertex of 3-I-1,2-C 2 B 10 H 11 , and at B8, B9, and B12 [27] of the [3,3'-Co(8,9,12-I 3 -…”

Section: Resultsmentioning

confidence: 99%

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Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters

Rojo

Teixidor

Viñas

et al. 2003

Chemistry A European J

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Regioselective monoalkylation and monoarylation in cobaltabisdicarbollide clusters has been achieved starting from Cs[8-I-3,3'-Co(1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))] by cross-coupling reactions between a B-I fragment and an appropriate Grignard reagent in the presence of a Pd catalyst and CuI. A considerable number of monoalkylated and monoarylated derivatives have been synthesized, which allowed study of the influence of boron in metallocene-type ligands and the effect of alkyl and aryl substituents on boron in boron anionic clusters. Experimental data from UV/Vis spectroscopy, E(1/2) measurements, and X-ray diffraction analysis, and supported by EHMO and ab initio analyses, indicate that the participation of metal d orbitals in the HOMO is less than that in typical metallocene complexes. This can be explained in terms of the lower electronegativity of boron compared to carbon. Related to this is the -I character of alkyl groups when bonded to boron in boron anionic clusters, contrary to the common belief that alkyl groups are generally electron-releasing moieties.

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Section: Resultsmentioning

confidence: 99%

“…[27] This opened up the possibility of achieving monosubstitution from [8-I-3,3'-Co(1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] À ( [2] À ). Figure 1 shows the numbering of the vertices for compound [2] À .…”

Section: Introductionmentioning

confidence: 99%

Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters

Rojo

Teixidor

Viñas

et al. 2003

Chemistry A European J

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“…The synthesis of these compounds wasn ow possible owing to the great advances in iodine substitution on the carborane cluster. [4] Earlier we and others had demonstrated that starting from monoiodinated metallacarboranes, [4,16] alkyl derivatives can be produced by am odification of the Kumada reaction. In Scheme 1, the syntheses of [3,3'-Co(9,12-I 2 -1,2-closo-C 2 B 9 H 9 ) 2 ] À (I 4 - [1] À )a nd [3,3'-Co(9,12-(Me) 2 -1,2-closo-C 2 B 9 H 9 ) 2 ] À ((Me) 4 - [1] À ), are shown.…”

Section: Resultsmentioning

confidence: 99%

“…À , [31] [3,3'-Co-(8-Me-1,2-closo-C 2 B 9 H 9 ) 2 ] À , [31] 3,3'-Co(8,9,10-I 3 -1,2-closo-C 2 B 9 H 8 ) 2 ] À , [16] ,3'-Co(8,9,10-Me 3 -1,2-closo-C 2 B 9 H 8 ) 2 ] À , [16] were synthesized as reported in the literature. The synthesis of [3,3'-Co-(8-Me-1,2-closo-C 2 B 9 H 9 ) 2 ] À and [3,3'-Co-(9,12-I 2 -1,2-closo-C 2 B 9 H 9 ) 2 …”

Section: Methodsmentioning

confidence: 99%

Negatively Charged Metallacarborane Redox Couples with Both Members Stable to Air

Lupu

Zaulet

Teixidor

et al. 2015

Chemistry A European J

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The metallacarborane [3,3'-Co(1,2-closo-C2B9H11)2](-) has been synthesized. This species allows the formation of redox couples in which both partners are negatively charged. The E1/2 potential can be tuned by adjusting the nature and number of substituents on B and C. The octaiodinated species [3,3'-Co(1,2-closo-C2B9H7I4)2](-) is the most favorable, as it is isolatable and stable in air. A DFT study on stability and redox potentials of complexes has been performed.

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“…The cobalt bis (dicarbollide) anion [3-Co-(1,2-C 2 B 9 H 11 ) 2 ] − ( Fig. 1) besides being the most investigated metallaheteroborane sandwich compound, it presents potential application in NLO [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of nonlinear optical properties of cobalt bis (dicarbollide) derivatives: the effect of substituents

Junqueira

Sato

2015

Theor Chem Acc

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interesting feature of the boron-based cages, due to high electronic and thermal stability, delocalized structures and easy functionalization, is the potential application in nonlinear optics (NLO) [3,5,21]. Generally, molecules with NLO applications are systems with acceptor and donor electron groups in its extremities (push-pull type), high values of first-order hyperpolarizability (β) and permanent dipole moment (d). The second-order responses can be enhanced by increasing the electronic asymmetry or the conjugation length between the extremity groups [22,23]. Besides, the structure must be non-centrosymmetric, and the molecules must present absorption at wavelength greater than 400 nm for second harmonic generation (SHG), to avoid re-absorption of the converted light [24]. The energy (E) of a molecular system under an external electric field F can be written as Eq. (1), where E(0) is the energy of the system in the absence of an external field, and F i are the components of the applied field [25]:The dipole moment (d), the linear polarizability (α), and the first-and second-order hyperpolarizabilities (β and γ) play a significant role mainly in the study of NLO properties [24,26,27].The NLO behavior of icosahedral carboranes has been investigated for more than 20 years [14]. Studies in this area involving carboranes include synthesis of novel compounds [14,18] and NLO properties' calculations [5,8,[15][16][17]21,28]. For example, a new class of dodecarboranes ([B 12 H 11 -C 2 B 10 H 11 ] 2− ) with potential application as NLO materials was proposed through ab initio calculations (1)In the present work, molecular first-order hyperpolarizability (β tot ) and dipole moment (d) are obtained at B3LYP/6-31G(d,p) level of theory by coupled perturbed Hartree-Fock method within the static approach. The investigated molecules are a series of substituted cobalt bis (dicarbollide) derivatives: Hydrogens bonded to the two carbon atoms are replaced by acceptor and donor electron substituents. Correlations between the Hammett electronic parameters of the substituents and the molecular properties are tested. Among them, the named push-pull compounds produced the largest calculated values of β tot and d. The UV-Vis spectra are reported for all studied compounds.

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Methylation of Boron Vertices of the Cobalt Dicarbollide Anion

Cited by 44 publications

References 18 publications

Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters

Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters

Negatively Charged Metallacarborane Redox Couples with Both Members Stable to Air

Theoretical study of nonlinear optical properties of cobalt bis (dicarbollide) derivatives: the effect of substituents

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Methylation of Boron Vertices of the Cobalt Dicarbollide Anion

Cited by 44 publications

References 18 publications

Relevance of the Electronegativity of Boron in η5‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C2B9H11)2]− Clusters

Relevance of the Electronegativity of Boron in η5‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C2B9H11)2]− Clusters

Negatively Charged Metallacarborane Redox Couples with Both Members Stable to Air

Theoretical study of nonlinear optical properties of cobalt bis (dicarbollide) derivatives: the effect of substituents

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Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters

Relevance of the Electronegativity of Boron in η⁵‐Coordinating Ligands: Regioselective Monoalkylation and Monoarylation in Cobaltabisdicarbollide [3,3′‐Co(1,2‐C₂B₉H₁₁)₂]⁻ Clusters