Structural studies of organoboron compounds. XXXVIII. 2,2-Diphenyl-4,4-tetramethylene-1,3,5-trioxa-3a-azonia-2-borata-2,3,4,5-tetrahydro-1H-cyclopenta[a]naphthalene

1990 ◽  
Vol 68 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Good Yield ◽  
Chelate Ring ◽  
Condensation Product ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Weakly Bound ◽  
Full Matrix

Reaction of oxybis(diphenylborane) with the condensation product of salicylohydroxamic acid and cyclopentanone gives the title compound in good yield. Crystals of 2,2-diphenyl-4,4-tetramethylene-1,3,5-trioxa-3a-azonia-2-borata-2,3,4,5-tetrahydro-1H-cyclopenta[a]naphthalene are monoclinic, a = 12.521(1), b = 12.409(1), c = 12.975(1) Å, β = 93.784(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 = 0.043 and Rw = 0.044 for 1502 reflections with I ≥ 2σ(I). The molecule has a typical diphenylboron hydroxamate structure featuring a five-membered COBON chelate ring. The O,O-chelating ligand is weakly bound to the diphenylboron moiety. Bond lengths (corrected for libration) include: (N)O—B = 1.558(4), (C=)O—B = 1.578(4), and C—B = 1.589(5) and 1.603(5) Å. Keywords: crystal structure, boron compound, organoboron compound.

Structural studies of organoboron compounds. XLII. 4,6-Bis(1-cyano-1-methylethyl)-2-mesityl-1,3-dioxa-4,6-diaza-2-boracyclohexane

1991 ◽  
Vol 69 (2) ◽  
pp. 234-238 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Least Squares ◽  
Key Words ◽  
Good Yield ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

The condensation of N,N′-bis(1-cyano-1-methylethyl)-N,N′-dihydroxymethanediamine and mesitylboronic acid gives 4,6-bis(1-cyano-1-methylethyl)-2-mesityl-1,3-dioxa-4,6-diaza-2-boracyclohexane in good yield. Crystals of the latter compound are orthorhombic, a = 15.825(1), b = 17.958(1), c = 14.014(1) Ǻ, Z = 8, space group Pbca. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.037 and Rw = 0.051 for 2844 reflections with 1 ≥ 3σ(I). The molecule has a six-membered cycloboronate structure featuring the first structurally characterized BONCNO ring. The ring was found to have a C-envelope conformation in the solid state. Bond lengths include: O—B(sp2) = 1.356(2) and 1.370(2), and C(aryl)—B = 1.560(2) Ǻ. Key words: organoboron compound, boron compound, crystal structure.

Structural studies of organoboron compounds. XXXV. 4,8-Diethyl-2,2,6,6-tetraphenyl-1,3,5,7-tetraoxa-4,8-diazonia- 2,6-diborata-1,2,3,5,6,7-hexahydronaphthalene

1989 ◽  
Vol 67 (10) ◽  
pp. 1644-1649 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Boron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Binding Strength ◽  
The Mean

The reaction of Ν,Ν′-diethyloxalohydroxamic acid with oxybis(diphenylborane) yields the title compound. Crystals of 4,8-diethyl-2,2,6,6-tetraphenyl-1,3,5,7-tetraoxa-4,8-diazonia-2,6-diborata-1,2,3,5,6,7-hexahydronaphthalene are monoclinic, a = 14.3405(9), b = 14.3053(5), c = 14.9301(8) Å, β = 116.136(4)°, Z = 4, space groupP21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.038 and Rw = 0.038 for 3501 reflections with I ≥ 3σ(I). The molecule has a novel bis-six-membered binuclear chelate structure, the Ph2B moieties each being coordinated by (N)O and (C=)O oxygen atoms from different hydroxamate groups. The mean libration-corrected bond distances (C=)O—B, 1.587 Å, (N)O—B, 1.511 Å, and B—C, 1.602 Å, represent the weakest overall binding strength of an O,O-chelating ligand with respect to the Ph2B moiety yet observed for a six-membered O—B—O chelate. Keywords: crystal structure, boron compound, organoboron compound.

Structural studies of organoboron compounds. XLIV. 2,3-Dihydro-3-hydroxy-2,2-tetramethylene-4H-benzoxazin-4-one and its difluoroboron chelate, 2,2-difluoro-4,4-tetramethylene-1,3,5-trioxa-3a-azonia-2-borata-2,3,4,5-tetrahydro- 1H-cyclopenta[a]naphthalene

1991 ◽  
Vol 69 (4) ◽  
pp. 673-680 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Boron Trifluoride ◽  
Chelate Ring ◽  
Direct Methods ◽  
Organoboron Compound ◽  
High Yield ◽  
Structural Studies ◽  
Crystal Forms ◽  
Full Matrix ◽  
Weak Binding

The reaction of 2,3-dihydro-3-hydroxy-2,2-tetramethylene-4H-benzoxazin-4-one, 2, and diethyl ether–boron trifluoride yields the difluoroboron chelate 2,2-difluoro-4,4-tetramethylene-1,3,5-trioxa-3a-azonia-2-borata-2,3,4,5-tetrahydro- 1H-cyclo-penta[a]naphthalene, 6, in high yield. There are two crystal forms of 2: 2a, triclinic, [Formula: see text] a = 8.551(1), b = 9.331(3), c = 7.236(1) Å, α = 103.38(2), β = 104.68(1), γ = 80.37(2)°, Z = 2, ρc = 1.35 g cm−3, and 2b, monoclinic, C2/c, a = 17.41(2), b = 10.665(6), c = 12.427(8) Å, β = 115.74(5)°, Z = 8, ρc = 1.40 g cm−3. Crystals of 6 are monoclinic, P21/c, a = 5.354(1), b = 17.654(2), c = 12.844(1) Å, β = 100.11(2)°, Z = 4, ρc = 1.48 g cm−3. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.046, 0.046, and 0.041 for 1712, 1505, and 1675 reflections with I ≥ 3σ(I), respectively. In both forms of 2, the structures consist of centrosymmetric [Formula: see text] hydrogen-bonded dimers [Formula: see text] for 2a and 2.682(3) Å for 2b). The difluoroboron chelate 6 features a five-membered chelate ring planar within 0.068(2) Å, and bond lengths O—B = 1.504(3) and 1.516(3), F—B = 1.358(3) and 1.359(3) Å indicate weak binding of the ligand to the F2B moiety. Key words: organoboron compound, crystal structure, boron compound

Structural studies of organoboron compounds. XXXVI. 2,2-Dimethyl-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclohexane

1989 ◽  
Vol 67 (12) ◽  
pp. 2218-2221 ◽  
Author(s):  
Klaus Drückler ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Boron Compound ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group

The synthesis of O-(2-hydroxyethyl)-N,N-dimethylhydroxylamine and its reaction with oxybis(diphenylborane) to yield the title compound are reported. Crystals of 2,2-dimethyl-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclohexane are orthorhombic, a = 7.0332(6), b = 9.2269(6), c = 22.967(2) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.051 and Rw = 0.047 for 1247 reflections with 1 ≥ 2σ(I). The molecule exhibits the longest N—B and the shortest O—B distances (1.723(6) and 1.468(5) Å, respectively, corrected for libration) yet reported for a six-membered N,O-chelate of diphenylboron. Keywords: crystal structure, boron compound, organoboron compound.

Structural studies of organoboron compounds. XXXIX.1 1,4-Bis(2,2-diethoxyethyl)-6,8-diphenyl-5,7,9-trioxa-4-aza-1-azonia-8- bora-6-boratabicyclo[4.3.0]nonane

1990 ◽  
Vol 68 (10) ◽  
pp. 1791-1796 ◽  
Author(s):  
Henning Amt ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Title Compound ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Reaction of N,N′-1,2-ethanediylidenebis(2,2-diethoxyethanamine)- N,N′-dioxide and phenylboronic acid yields the title compound. Crystals of 1,4-bis(2,2-diethoxyethyl)-6,8-diphenyl-5,7,9-trioxa-4-aza-1-azonia-8-bora-6-boratabicyclo[4.3.0]-nonane are triclinic, a = 12.625(2), b = 13.962(2), c = 9.273(1) Å, α = 104.81(1), β = 98.61(1), γ = 106.52(1)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.058 and Rw = 0.081 for 3677 reflections with I ≥ 3σ(I). The molecule has a bicyclo[4.3.0]nonane structure containing one transannular N—B bond. Important bond lengths are sp3-bomn, N—B = 1.759(3), O—B = 1.435(3) and 1.454(3), C—B = 1.579(4); sp2-boron, O—B = 1.335(3) and 1.404(3), C—B = 1.557(4) Å. The (sp3)B—C(phenyl) bond is the shortest yet reported for this type of compound.Keywords: crystal structure, boron compound, organoboron compound.

Structural studies of organoboron compounds. XLIII. 4-[(1-Hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene

1991 ◽  
Vol 69 (3) ◽  
pp. 545-549 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ute Schumacher ◽  
Mahmood Tajerbashi ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Hydroxamic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths ◽  
Acid Chelate

The reaction of N′-hydroxy-N-[(1-hydroxycyclohexyl)methyl]benzamide and diphenylborinic anhydride gives 4-[(1-hydroxycyclohexyl)methyl]-2,2,5-triphenyl-1,3-dioxa-4-azonia-2-borata-4-cyclopentene in nearly quantitative yield. Crystals of the product are monoclinic, a = 9.9117(6), b = 13.308(1), c = 17.339(2) Ǻ, β = 99.420(7)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.047 for 2423 reflections with I > 3σ(I). The molecule has a normal five-membered hydroxamic acid chelate structure, the BONCO ring having a B-envelope conformation. Bond lengths (corrected for libration) (N)O—B = 1.535(3), (C)O—B = 1.569(3), C—B = 1.603(3) and 1.601(3) Ǻ are normal for this type of complex. Key words: organoboron compound, boron compound, crystal structure.

Structural studies of organoboron compounds. LIII. N,N-Diethylhydroxylamine-(O-B)1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5- boratabicyclo[3.3.0]octane

1992 ◽  
Vol 70 (7) ◽  
pp. 2022-2026 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Hydrogen Bond ◽  
Least Squares ◽  
Title Compound ◽  
Condensation Product ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
High Yield ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

Reaction of the condensation product of N,N′-dimethyl-N,N′-dihydroxymethanediamine and phenylboronic acid with N,N-diethylhydroxylamine gives N,N-diethylhydroxylamine(O-B)1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane [3-(2-ethyl-1-oxa-2-azoniabutyl)-1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3,5-diboratabicyclo[3.3.0]octane, 3] in high yield. Crystals of 3 are orthorhombic, a = 11.8132(11), b = 15.4768(11), c = 11.7325(16) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039 and Rw = 0.044 for 1729 reflections with I ≥ 2σ(I). The title compound is the second example of this recently characterized class of O-B coordinated hydroxylamine complexes, stabilized by an intramolecular [Formula: see text] hydrogen bond [Formula: see text]. Bond lengths about boron are: B—O(N) = 1.482(4)–1.526(4), B—O(B) = 1.412(4) and 1.420(4), B—N = 1.712(4), B—C = 1.591(5) and 1.602(5) Å.

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 XLVIII. 1,4-Diphenyl-3,3:6,6-bis(tetramethylene)-2,5,7-trioxa-3,6-diazonia-1,4-diboratabicyclo[2.2.1]heptane

1991 ◽  
Vol 69 (8) ◽  
pp. 1222-1226 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ulf Riebe ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Ring System ◽  
Structural Studies ◽  
Full Matrix ◽  
Moderate Yield ◽  
Atom Bond ◽  
Axis Passing

The reaction of N-hydroxypyrrolidine with either oxybis(diphenylborane) or phenylboronic acid gives 1,4-diphenyl-3,3:6,6-bis(tetramethylene)-2,5,7-trioxa-3,6-diazonia-1,4-diboratabicyclo[2.2.1]heptane in moderate yield. Crystals of the product are orthorhombic, a = 10.984(2), b = 14.619(2), c = 12.311(2) Å, Z = 4, space group Pccn. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039 and Rw = 0.043 for 908 reflections with I ≥ 3σ(I). This is the first heterocyclic [2.2.1]heptane system containing a six-membered BONBON ring and a B—O—B bridge to be structurally characterized. The molecule has exact C2 symmetry with the twofold axis passing through the bridging oxygen atom. Bond lengths involving the tetrahedrally coordinated boron atom are B—O(B) = 1.423(3), B—O(N) = 1.497(3), B—N = 1.703(3), and B—C(phenyl) = 1.577(4) Å. Key words: 2,5,7-trioxa-3,6-diazonia-1,4-diboratabicyclo[2.2.1]heptane ring system, crystal structure, organoboron compound.

Structural studies of organoboron compounds XL. 4,7-Dicyclohexyl-2,2,5,6-tetraphenyl- 1,3-dioxa-4-aza-7-azonia-2-boratacycloheptane

1990 ◽  
Vol 68 (10) ◽  
pp. 1797-1802 ◽  
Author(s):  
Henning Amt ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Least Squares ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Chair Conformation ◽  
Membered Ring ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths

The synthesis of 4,7-dicyclohexyl-2,2,5,6-tetraphenyl-1,3-dioxa-4-aza-7-azonia-2-boratacycloheptane is reported. Crystals of the compound are orthorhombic, a = 10.893(1), b = 28.072(1), c = 10.596(1) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.036 and Rw = 0.043 for 2480 reflections with I ≥ 3σ(I). The molecule has a seven-membered chelate structure. The seven-membered ring, which has a twisted chair conformation, is stabilized by an intramolecular [Formula: see text] hydrogen bond. Bond lengths O—B = 1.468(4) and 1.554(4), C—B = 1.621(5) and 1.626(4) Å are consistent with moderately strong binding of the diphenylboron moiety by the O,O-chelating ligand. Keywords: crystal structure, organoboron compound, boron compound.

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