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. 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. XLIX. 4,6-Bis(1-phenyl-2-nitroethyl)-2-(4-methoxyphenyl)-1,3-dioxa-4,6-diaza-2-boracyclohexane

1991 ◽  
Vol 69 (8) ◽  
pp. 1227-1232 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Boron Atom ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Structural Studies ◽  
Subsequent Reaction ◽  
Full Matrix ◽  
Bond Lengths

The preparation of N,N′-bis(1-phenyl-2-nitroethyl)-N,N′-dihydroxymethanediamine and its subsequent reaction with 4-methoxyphenylboronicacid to yield 4,6-bis(1-phenyl-2-nitroethyl)-2-(4-methoxyphenyl)-1,3-dioxa-4,6-diaza-2-boracyclohexane are described. Crystals of the latter compound are monoclinic, a = 8.4790(8), b = 16.2100(9), c = 9.4367(6) Å, β = 109.342(5)°, Z = 2, space groupP21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.032 and Rw = 0.039 for 1749 reflections with I ≥ 3σ(I). The molecule has a six-membered BONCNO cycloboronate structure. Bond lengths involving the trigonal planar boron atom are (N)O—B = 1.362(4) and 1.364(5), (aryl)C—B = 1.548(4) Å. Key words: organoboron compound, crystal structure, cycloboronate, methanediamine.

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.

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. XLV. 5,5-Difluoro-2,2-pentamethylene-7,7-diphenyl-1,4,6-trioxa-3a-azonia-5-borata-2,3,4,5,6,7-hexahydroindene

1991 ◽  
Vol 69 (4) ◽  
pp. 681-686 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ute Schumacher ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Key Words ◽  
Boron Trifluoride ◽  
Direct Methods ◽  
Organoboron Compound ◽  
Hydroxamic Acids ◽  
Structural Studies ◽  
Full Matrix ◽  
Regioselective Alkylation

The reaction of N,-dihydroxy-N-(1-hydroxycyclohexyl)methyl-2,2-diphenylacetamide with dimethyl ether-boron trifluoride gives 5,5-difluoro-2,2-pentamethylene-7,7-diphenyl-1,4,6-trioxa-3a-azonia-5-borata-2,3,4,5,6,7-hexahydroindene in nearly quantitative yield. Crystals of the product are triclinic, a = 9.4555(5), b = 9.9813(6), c = 10.5139(9) Å, α = 72.654(7), β = 77.140(5), γ = 88.542(6)°, 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 = 0.044 and Rw = 0.060 for 2971 reflections with I ≥ 3σ(I). The molecule has a six-membered difluoroboron chelate structure, confirming that the regioselective alkylation of N-substituted hydroxamic acids under non-basic conditions leads to imidate N-oxides in cases where intramolecular alkylation occurs. Bond lengths (corrected for libration): (N)O—B = 1.530(3), (C)O—B = 1.451(2), F—B = 1.389(3) and 1.379(3) Å indicate relatively strong binding of the BF2+moiety by the O,O-chelating ligand. Key words: organoboron compound, crystal structure, boron compound.

Structural studies of organoboron compounds. XLI. (3-Hydroxy-2-methyl-1-(p-tolyl)-4-pyridinonato)diphenylboron

1990 ◽  
Vol 68 (10) ◽  
pp. 1803-1807 ◽  
Author(s):  
Chris Orvig ◽  
Steven J. Rettig ◽  
James Trotter ◽  
Zaihui Zhang
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Direct Methods ◽  
Organoboron Compound ◽  
High Yield ◽  
Structural Studies ◽  
Full Matrix ◽  
Bond Lengths ◽  
The Mean ◽  
Independent Molecules

(3-Hydroxy-2-methyl-1-(p-tolyl)-4-pyridinonato)diphenylboron has been prepared in high yield by the reaction of 3-hydroxy-2-methyl-1-(p-tolyl)-4-pyridinone with diphenylborinic acid. Crystals of the hemi-acetone solvate are triclinic, a = 15.119(2), b = 16.528(1), c = 9.5802(9) Å, α = 98.721(6), β = 93.344(8), γ = 102.443(6)°, 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 = 0.050 and Rw = 0.065 for 4330 reflections with I ≥ 3σ(I). The five-membered chelate rings in both of the two crystallographically independent molecules have flattened B-envelope conformations (maximum deviations from the mean planes = 0.114(4) and 0.065(5) Å). Mean bond lengths O—B = 1.553 and C—B = 1.599 Å are consistent with intermediate strength binding of the diphenylboron moiety by the O,O-chelating ligand. Keywords: crystal structure, organoboron compound.

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.

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. 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. 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.

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