Structural studies of organoboron compounds. LVII. Synthesis and structure of bicyclic boron-nitrogen betaines. 1-Methyl-5-(3-nitrophenyl)-4,6,9-trioxa-1-azonia-5-boratabicyclo[3.3.1]nonane and 3,3,4-trimethyl-1-(3-nitrophenyl)-2,6,7-trioxa-3-azonia-1-boratabicyclo[2.2.2]octane

1993 ◽  
Vol 71 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Eckart Ahlenstiel ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Boron Atom ◽  
Crystal Packing ◽  
Direct Methods ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Boron Nitrogen ◽  
Tetrahedral Boron

The syntheses and structures of the bicyclic boron-nitrogen betaines 1-methyl-5-(3-nitrophenyl)-4,6,9-trioxa-1-azonia-5-boratabicyclo[3.3.1]nonane, 7a, and 3,3,4-trimethyl-1-(3-nitrophenyl)-2,6,7-trioxa-3-azonia-1-boratabicyclo[2.2.2]-octane, 14a, are reported. Crystals of 7a are orthorhombic, a = 20.256(2), b = 37.652(2), c = 6.642(1) Å, Z = 16, space group Fdd2, and those of 14a are orthorhombic, a = 21.402(2), b = 11.334(3), c = 11.248(2) Å, Z = 8, space group Pbca. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.038 and 0.045 (Rw = 0.036 and 0.053) for 975 and 1646 reflections with I ≥ 3σ(F2), respectively. The X-ray analyses establish the bicyclo[3.3.1]nonane and bicyclo[2.2.2]octane "cage" structures for 7a and 14a, respectively. Bond lengths involving the tetrahedral boron atom are (N)O—B = 1.519(5), (C)O—B = 1.444(6) and 1.443(6), C(aryl)—B = 1.602(5) Å for 7a; and (N)O—B = 1.530(3), (C)O—B = 1.446(3) and 1.455(3), C(aryl)—B = 1.608(3) Å for 14a. Weak [Formula: see text] interactions are the main feature of the crystal packing arrangements of both compounds.

Structural studies of organoboron compounds. LX. Reaction of sterically hindered arylboronic acids with 2-(hydroxyamino)alkanols. Crystal and molecular structure of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane

1994 ◽  
Vol 72 (4) ◽  
pp. 1154-1161 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Arylboronic Acids ◽  
Sterically Hindered

Three 2-(hydroxyamino)alkanols have been reacted with sterically hindered arylboronic acids, ArB(OH)2. When Ar = o-tolyl, 1:2 condensates having bicyclic structures are formed but when Ar = mesityl (2,4,6-(CH3)3C6H2), 1:1 condensates having six-membered cycloboronate structures result. These 1:1 condensates represent the first examples of N-unsubstituted 1,3-dioxa-4-aza-2-boracyclohexane derivatives. An X-ray analysis of one example provides unambiguous proof of the structure. Crystals of 2-mesityl-6,6-pentamethylene-1,3-dioxa-4-aza-2-boracyclohexane, 3c, are monoclinic, a = 11.076(9), b = 23.94(2), c = 13.414(9) Å, β = 109.40(5)°, Z = 8, space group P21/n. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.051 and Rw = 0.058 for 2037 reflections with I ≥ 3σ(F2).

Structural studies of organoboron compounds. XV. Crystal and molecular structures of (3-aminopropanolato)diphenylboron, (2-N,N-dimethylaminoethanolato)diphenylboron, and (2-N,N-dimethylaminoethanolato)diphenylboron – diphenylborinic acid (1:1)

1983 ◽  
Vol 61 (10) ◽  
pp. 2334-2340 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Boron Atom ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures

Crystals of (3-aminopropanolato)diphenylboron are monoclinic, a = 9.6717(13). b = 9.8867(6), c = 14.452(2) Å, β = 99.500(7)°, Z = 4, space group P21/n: those of (2-N,N-dimethylaminoethanolato)diphenylboron are monoclinic, a = 7.0721(4), b = 16.8829(4), c = 12.0975(8) Å, β = 97.875(3)°, Z = 4, space group Cc; and those of (2-N,N-dimethylaminoethanolato)diphenylboron – diphenylborinic acid (1:1) are monoclinic. a = 11.3231(10). b = 19.3190(12). c = 12.2451(11) Å, β = 109.321(4)°, Z = 4, space group P21/n. All three structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.038. 0.031, and 0.040 for 1522, 1649, and 2420 reflections with I ≥ 3σ(I) respectively. Each structure contains a tetrahedrally coordinated boron atom. The libration-corrected B—O, B—N, and mean B—C distances are: 1.481(2), 1.643(3), and 1.623(3) Å for (3-aminopropanolato)diphenylboron; 1.476(2), 1.691 (2), and 1.625(7) Å for (2-N,N-dimethylaminoethanolato)diphenylboron. The Ph2BOH molecule contains a trigonal-planar boron atom with B—O = 1.354(3) Å and mean B—C = 1.572(3) Å.

Structural studies of organoboron compounds L. 4-(2-Hydroxy-2,2-diphenylacetyl)- 6,6-pentamethylene-2-phenyl-1,3-dioxa-4-aza-2-boracyclohexane and 4-[2,2-difluoro-5,5-bis(4-methoxyphenyl)-1,3-dioxa-2-borata-4-cyclopentylidene]- 6,6-pentamethylene-2-phenyl-1,3-dioxa-4-azonia-2-boracyclohexane

1992 ◽  
Vol 70 (4) ◽  
pp. 1176-1187 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Lutz Preu ◽  
Ute Schumacher ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Hydrogen Atom ◽  
Least Squares ◽  
Boron Atom ◽  
Chelate Ring ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Bond Lengths ◽  
Tetrahedral Boron

The preparation of the organoboron compounds 4-(2-hydroxy-2,2-diphenylacetyl)-6,6-pentamethylene-2-phenyl-1,3-dioxa-4-aza-2-boracyclohexane, 6, 4-(2,2-difluoro-5,5-diphenyl-1,3-dioxa-2-borata-4-cyclopentylidene)-6,6-pentamethylene-2-phenyl-1,3-dioxa-4-azonia-2-boracyclohexane, 14a, and 4-[2,2-difluoro-5,5-bis(4-methoxyphenyl)-1,3-dioxa-2-borata-4-cyclopentylidene]-6,6-pentamethylene-2-phenyl-1,3-dioxa-4-azonia-2-boracyclohexane, 14b, are reported. Crystals of 6 are triclinic, [Formula: see text], a = 8.7348(5), b = 11.0529(6), c = 14.104(1) Å, α = 65.781(5)°, β = 72.147(6)°, γ = 79.928(6)°, Z = 2, ρc = 1.130 g cm−3, and crystals of 14b•1/2 CH2Cl2 are also triclinic, [Formula: see text], a = 11.799(1), b = 13.464(2), c = 10.047(2) Å, α = 103.28(2)°, β = 92.60(2)°, γ = 79.752(8)°, Z = 2, ρc = 1.285 g cm−3. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.040 and 0.060 for 3881 and 3221 reflections with I ≥ 3σ(I), respectively. Compound 6 has a six-membered cycloboronate structure, bond distances involving the trigonal planar boron atom being (N)O—B = 1.390(2), (C)O—B = 1.345(2), and B—C(phenyl) = 1.557(2) Å. Compound 14b represents a derivative of 6 in which an intramolecularly hydrogen-bonded hydrogen atom has been replaced by a difluoroboron moiety and represents the first structurally characterized compound containing both a phenylboronate and a difluoroboron chelate ring within the same molecule. Bond lengths in 14b involving the trigonal planar boron atom are (N)O—B = 1.403(5), (C)O—B = 1.326(5), and B—C(phenyl) = 1.550(5) Å and those involving the tetrahedral boron atom are O—B = 1.427(5) and 1.547(5), F—B = 1.353(5) and 1.382(5) Å.

Structural studies of organoboron compounds LVIII. 4-(1′-azoniabicyclo[2.2.2]-octanyl)-2,2-diphenyl-2-borata-1,3-dioxa-1,2,3,4-tetrahydronaphthalene

1993 ◽  
Vol 71 (6) ◽  
pp. 919-923 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Klaus Drückler ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Carbonyl Compound ◽  
Boron Atom ◽  
Lewis Acid ◽  
Direct Methods ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystalline Adduct ◽  
Synthetic Routes

Two synthetic routes leading to 4-(1′-azoniabicyclo[2.2.2]octanyl)-2,2-diphenyl-2-borata-1,3-dioxa-1,2,3,4-tetrahydronaphthalene, 5, are described. Crystals of the product are orthorhombic, a = 18.099(2), b = 9.729(2), c = 12.113(2) Å, Z = 4, space group Pca21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.034 and Rw = 0.037 for 1421 reflections with I > 3σ(F2). Compound 5 represents the first structurally characterized crystalline adduct of a trialkylamine to a carbonyl compound in which the newly formed C—N bond is acyclic. The adduct is stabilized by the neighboring Lewis acid diphenylboryloxyaryl moiety. Bond distances involving the boron atom ((aryl)O—B = 1.515(4), (alkyl)O—B = 1.508(4), and C(phenyl)—B = 1.613(5) and 1.623(5) Å) represent relatively strong overall binding of the O,O-chelating ligand to the diphenylboron moiety.

Structural studies of organoboron compounds. XIV. Preparation and crystal and molecular structure of 4-isopropylidene-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane

1983 ◽  
Vol 61 (10) ◽  
pp. 2329-2333 ◽  
Author(s):  
W. Kliegel ◽  
D. Nanninga ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Physical Properties ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Tetrahedral Boron

Details of the synthesis, physical properties, and molecular structure of 4-isopropylidene-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane are reported. Crystals of this compound are monoclinic, a = 14.126(3), b = 16.008(1), c = 8.642(2) Å, β = 99.052(8)°, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.032 and Rw = 0.033 for 1117 reflections with I ≥ 3σ(I). The molecule contains a nearly planar five-membered B—O—B—O—N ring which incorporates both trigonal planar boron (B—O = 1.333(4) and 418(4), B—C = 1.548(5) Å) and tetrahedral boron atoms (B—O = 1.495(4), B—N = 1.676(4), B—C = 2 at 1.603(5) Å). Other important libration-corrected bond distances include: C=N = 1.284(3) and N—O = 1.418(3) Å.

Structural studies of organoboron compounds. XX.(Salicylaldoximato-O,N)diphenylboron

1984 ◽  
Vol 62 (7) ◽  
pp. 1363-1368 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Hydrogen Bonds ◽  
Least Squares ◽  
Chelate Ring ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Phenolic Oxygen

Crystals of (salicylaldoximato-O,N)diphenylboron are triclinic, a = 10.125(2), b = 10.797(1), c = 14.760(2) Å, α = 89.05(1), β = 86.98(1), γ = 83.18(1)°, Z = 4, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.048 for4145 reflections with I ≥ 3σ(I). The structure consists of two crystallographically independent, but essentially identical, molecules linked by strong [Formula: see text] hydrogen bonds to form continuous spirals along the a axis. The Ph2B moiety is chelated by the phenolic oxygen and oxime nitrogen atoms of the ligand resulting in the formation of a non-planar six-membered chelate ring. Important libration-corrected mean bond lengths are O—B = 1.516(1), N—B = 1.609(2), and C—B = 1.613(2) Å.

Structural studies of organoboron compounds. XXXII. 5,5-Difluoro-2,2-pentamethylene-1,4,6-trioxa-3a-azonia-5-borata-1,2,3,4,5,6-hexahydrobenzo[h]azulene and 2,2-pentamethylene-5,5-diphenyl-1,4,6-trioxa-3a-azonia-5-borata-1,2,3,4,5,6-hexahydrobenzo[h]azulene

1988 ◽  
Vol 66 (10) ◽  
pp. 2621-2630 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Solid State ◽  
Physical Properties ◽  
Least Squares ◽  
Crystal Structures ◽  
Direct Methods ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Conformational Isomers

Details of the syntheses, physical properties, and crystal structures of the title compounds are reported. Crystals of 5,5-difluoro-2,2-pentamethylene-1,4,6-trioxa-3a-azonia-5-borata-1,2,3,4,5,6-hexahydrobenzo[h]azulene are triclinic, a = 6.1576(3), b = 11.2651(3), c = 10.8118(3) Å, α = 109.747(3), β = 105.807(4), γ = 92.976(4)°, Z = 2, space group [Formula: see text], and those of 2,2-pentamethylene-5,5-diphenyl-1,4,6-trioxa-3a-azonia-5-borata-1,2,3,4,5,6-hexahydrobenzo[h]azulene are monoclinic, a = 9.8549(6), b = 10.9242(6), c = 41.263(2) Å, β = 92.717(6)°, Z = 8, space group P21/n. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.045 and 0.042 for 2344 and 4248 reflections with I ≥ 3σ(I), respectively. The molecules were both found to possess a seven-membered chelate structure, the O,O-chelatїng ligand being strongly bound to the X2B moiety. Two conformational isomers of the X = Ph compound were found in the solid state. The 2-oxazoline N-oxide moieties present in both compounds are the first to be structurally characterized. Important mean libration-corrected bond lengths are: O—B = 1.491 and F—B = 1.387 Å for X = F; O—B = 1.511 and C—B = 1.620 Å for X = Ph.

Ring contraction of 4-substituted 2,6-dichlorophenols. The crystal structure of 2,2,4α,5α-Tetrachloro-1α,3α-dihydroxycyclopentane-1,4-carbolactone

1977 ◽  
Vol 30 (10) ◽  
pp. 2195 ◽  
Author(s):  
RM Christie ◽  
RW Rickards ◽  
KJ Schmalzl ◽  
D Taylor
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Major Product ◽  
X Ray Diffraction ◽  
Ring Contraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Counter Data

Alkaline chlorination of the 4-alkyl-2,6-dichlorophenols (2b) and (2c) proceeds through ring contraction and halolactonization to form the 4α- alkyl-2,2,5α-trichloro-1α,3α-dihydroxycyclopentane-1,4-carbolactones (4b) and (4c). Under similar conditions, 2,4,6-trichlorophenol affords the analogous 2,2,4α,5α-tetrachloro-1α,3α-dihydroxycyclopentane-1,4- carbolactone (4a) in low yield, in addition to the Hantzsch acid (3a) as the major product. The acid (3a) upon further treatment undergoes chloro-lactonization to give the lactone (4a). The structures of the lactones (4b) and (4c) follow from spectroscopic comparison with (4a), the structure of which has been established by X-ray diffraction (C6H4Cl4O4 orthorhombic a 13.485(1), b 12.348(1), c 11.371(1) Ǻ, space group Pccn, Z 8, solved by direct methods and refined by block-diagonal and full-matrix least squares to R 0.031, Rw 0.043 for 1313 unique counter data with I/σ(I) ≥ 3.0).

Structural studies of organoboron compounds. XXIX. 6,6-Diethyl-2,2-diphenyl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate

1988 ◽  
Vol 66 (5) ◽  
pp. 1091-1096 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Title Compound ◽  
Chelate Ring ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Conformation Intermediate

Details of the preparation and structure of the title compound are given. Crystals of 6,6-diethyl-2,2-diphenvl-1,3-dioxa-6-azonia-2-boratacyclooctane monohydrate are orthorhombic, a = 7.0322(2), b = 16.3505(7), c = 16.8164(4) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.045 and Rw = 0.050 for 2013 reflections with I ≥ 3σ(I). The monocyclic eight-membered B, N-betaine is the first to be structurally characterized. The eight-membered chelate ring has a conformation intermediate between the S4 and boat-boat forms which is probably stabilized by transannular [Formula: see text] interactions. The average libration-corrected O—B and B—C bond lengths of 1.500 and 1.639 Å are, respectively, the shortest and longest yet observed for an O,O-chelate of diphenylboron.

Structural studies of organoboron compounds. XVI. Preparation and crystal and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane

1984 ◽  
Vol 62 (5) ◽  
pp. 838-844 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Physical Properties ◽  
Least Squares ◽  
Steric Hindrance ◽  
Direct Methods ◽  
Structural Features ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures

Details of the synthesis, physical properties, and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane, 4, and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 5, are reported. Crystals of 4 are triclinic, a = 9.841(2), b = 14.722(3), c = 6.6701(12) Å, α = 86.79(1), β = 102.95(1), γ = 93.89(1)°, Z = 2, space group [Formula: see text]; and those of 5 are monoclinic, a = 14.9164(12), b = 6.4732(3), c = 18.2248(15) Å, β = 117.263(3)°, Z = 4, space group Cc. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.032 and 0.035 for 1456 and 1649 observed reflections, respectively. Molecules of 4 contain non-planar BOBON rings with an unusually long N(sp3)—B(sp3) distance of 1.728(3) Å and in 5 there is a long N(sp3)—C(sp3) bond of 1.591(3) Å. These structural features are ascribed to steric hindrance.

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