Blaues Tetrakis(diisopropylamino)-cyclo-tetraboran und gelbes Tetrakis(tetramethylpiperidino)tetrabora-tetrahedran

Maier, Claus-Jürgen; Pritzkow, Hans; Siebert, Walter

doi:10.1002/(sici)1521-3757(19990601)111:11<1772::aid-ange1772>3.0.co;2-x

Cited by 27 publications

(5 citation statements)

References 16 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For comparison, in [BCl(NMe 3 )] 2 B−Cl bond distances of 186 and 189 pm have been measured. These values are much larger than those adopted in three-coordinated diborane species (e.g., 181.9(4) pm in [BCl(NH i Pr 2 )] 2 and 177.0(5)/177.4(4) pm in [BCl(Mes)] 2 (Mes = mesityl)) . The B←NHMe 2 donor bond is again more than 5 pm larger than the B−N bonds to the hpp − ligands.…”

Section: Resultsmentioning

confidence: 78%

See 1 more Smart Citation

First Dinuclear B(II) Monocations with Bridging Guanidinate Ligands: Synthesis and Properties

et al. 2008

View full text Add to dashboard Cite

Reaction between the diborane (4) B2Cl2(NMe2)2 and Li(hpp) (hpp-=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate) leads to [(Me2N)B(mu-hpp)] 2. This species can be protonated by HCl.OEt2 to give [(Me2HN)B(mu-hpp)]2Cl2 featuring two B(II) cations with direct B-B bonding. The unsymmetrical monocation [(Me2N)B2(mu-hpp)2(NHMe2)]+ is also obtained. [(Me2HN)B(mu-hpp)]2Cl2 eliminates NHMe2 in a slow reaction leading to [ClB2(mu-hpp)2(NHMe2)]Cl and ultimately, presumably, to [ClB(mu-hpp)]2. We report the crystal structures of the two monocations [ClB2(mu-hpp)2(NHMe2)]Cl and [(Me2N)B2(mu-hpp)2(NHMe2)]Cl. The experimental results are accompanied by some quantum chemical density-functional theory calculations.

show abstract

Section: Resultsmentioning

confidence: 78%

“… a Please note that the atom numbering for 2b differs from that in ref to make it similar to that of the other compounds. …”

Section: Introductionmentioning

confidence: 99%

First Dinuclear B(II) Monocations with Bridging Guanidinate Ligands: Synthesis and Properties

et al. 2008

View full text Add to dashboard Cite

show abstract

“…For 222b , a torsion angle of 160° between the keto and thioketone groups was calculated, while the ester carbonyl and the thioketone group have a torsion angle of 55.3° . Further congeners of the cyclic vic -polyketones are the aminoboranes ( 223 , 224 ) for which alkyl derivatives of the tetramer and hexamer have been reported …”

Section: Related Systems (Chart )mentioning

confidence: 99%

The Chemistry of Vicinal Polycarbonyl Compounds

2000

View full text Add to dashboard Cite

“…Molecular orbital (MO) studies [2] have indicated that planar B 4 rings are unstable. By reacting the more sterically hindered diisopropylamino derivative of 14 with Na/K alloy, we were surprised by isolating blue crystals of 2a (18 %, λ max = 620 nm, ε = 40, δ 11 B = 65) and the colorless tetraborane(6) (iPr 2 N) 4 B 4 H 2 (2 %), both confirmed by X-ray diffraction studies [9]. In addition, some colorless diborene (iPr 2 N) 2 B 2 was detected as a part of a mixture that included other unidentified products.…”

Section: Cyclo-boranes and Polyhedral-boranesmentioning

confidence: 99%

Small boranes, carboranes, and heterocarboranes

Siebert

Maier

et al. 2003

Pure and Applied Chemistry

View full text Add to dashboard Cite

Dehalogenation of 1,2-dichloro-diborane(4) derivatives with Na/K alloy does not lead to planar cyclo-tetraboranes but to the blue puckered diisopropylamino compound and to the yellow 2,2,6,6-tetramethylpiperidino-tetraboratetrahedrane derivative, respectively. With smaller dialkylamino substituents, the formation of orange-red cyclo-hexaborane (BNMe 2 ) 6 and the green closo-hexaborane (BNEt 2 ) 6 is observed. When a 1:1 mixture of Me 2 NBCl 2 and [Me 2 N(Cl)B] 2 is dehalogenated, a small amount of colorless crystals of the planar diamond-shaped tetrabora-bicyclo-butane [(Me 2 N) 2 BB−BNMe 2 ] 2 is obtained. Its MO analysis reveals that eight framework electrons are used to form two 3c,2e σ bonds, one 4c,2e π bond, and one 4c,2e σ bond along the edges.A new approach to reactive closo-dicarbapentaboranes involves the hydroboration of dichloroboryl-tbutylacetylene with HBCl 2 leading to Me 3 CCH 2 C(BCl 2 ) 3 . On heating, it is transformed into the closo-dicarbapentaborane (Me 3 CCH 2 C) 2 (BCl) 3 , in which the chlorine atoms may be substituted to give new derivatives.By reacting B 2 Cl 4 with C 5 Me 5 -SiMe 3 the nido-1-borane-2,3,4,5,6-pentacarbahexaborane(6) is stabilized by the Lewis acid BCl 3 to give (MeC) 5 B−BCl 3 .Hydroboration of 3,4-bis(isopropylidene)-1,3-diborolanes leads to the formation of nido-2,3,5-tricarbahexaboranes(7), which may be deprotonated to give the corresponding anions isolobal with C 5 H 5 − . Heterotricarbahexaboranes are obtained when a 3,4-bis(dichloroboryl)-2,5-hexadiene derivative is reacted with heptamethyldisilazane and hexamethyl-disilthiane to give the corresponding 1,2,5-azadiborolane and thiadiborolane. Their hydroboration leads to the aza-and thia-nido-dicarbahexaboranes, respectively.

show abstract

Blaues Tetrakis(diisopropylamino)-cyclo-tetraboran und gelbes Tetrakis(tetramethylpiperidino)tetrabora-tetrahedran

Cited by 27 publications

References 16 publications

First Dinuclear B(II) Monocations with Bridging Guanidinate Ligands: Synthesis and Properties

First Dinuclear B(II) Monocations with Bridging Guanidinate Ligands: Synthesis and Properties

The Chemistry of Vicinal Polycarbonyl Compounds

Small boranes, carboranes, and heterocarboranes

Contact Info

Product

Resources

About