Structural studies of organoboron compounds LIX. Reaction of two sterically hindered N,N′-dihydroxyaminals with phenylboronic acid, and the crystal and molecular structures of the resulting 1,3,5-trioxa-6,8-diaza-2,4-diboracyclooctanes and one of the adducts

1993 ◽  
Vol 71 (12) ◽  
pp. 2129-2138 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Bond Order ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Bond Orders ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Transannular Interaction ◽  
Sterically Hindered

The syntheses of the sterically hindered N,N′-dihydroxyaminals; N,N′-bis(1-ethoxycarbonyl-1-methylethyl)-N,N′-dihydroxymethanediamine, 1b, and N,N′-bis(1,1-dimethylethyl)-N,N′-dihydroxymethanediamine, 1c, and their reactions with phenylboronic acid to yield the 1,3,5-trioxa-6,8-diaza-2,4-diboracyclooctanes 3 and 4, respectively, are described. Crystals of 1b are tetragonal, a = 18.413(1), c = 9.867(2) Å, Z = 8, space group I41; those of 3 are monoclinic, a = 20.420(4), b = 8.272(4), c = 17.851(5) Å, β = 117.34(1)°, Z = 4, space group C2/c; and those of 4 are monoclinic, a = 9.493(4), b = 16.202(4), c = 14.783(3) Å, β = 101.90(2)°, Z = 4, space group P21/c. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.034, 0.039, and 0.040 (Rw = 0.035, 0.034, and 0.036) for 1550, 1438, and 2187 reflections with I ≥ 3σ(F2), respectively. In the solid state, both 3 and 4 exhibit transannular [Formula: see text] interactions. In 3 there are two identical (by symmetry) interactions with [Formula: see text] Å that have estimated bond orders of 0.06, while the single transannular interaction in 4 has N—B = 1.953(3) Å and a bond order of about 0.3. The intermediate-strength transannular interaction in 4 is the first to be reported for this type of molecule.

Structural studies of organoboron compounds. XXI. Crystal and molecular structures of 3-(phenylmethylidene)-4-methyl-1-phenyl-2,6,7-trioxa-3-azonia-1-boratabicyclo-[2.2.2]octane and N-(4-nitrophenylmethylidene)-5-methyl-2-phenyl-1,3-dioxa-2-bora-5-cyclohexaneamine N-oxide

1985 ◽  
Vol 63 (2) ◽  
pp. 509-515 ◽  
Author(s):  
W. Kliegel ◽  
L. Preu ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Condensation Products ◽  
Crystal And Molecular Structures ◽  
Bicyclic Structure

Crystals of 3-(phenylmethylidene)-4-methyl-1-phenyl-2,6,7-trioxa-3-azonia-1-boratabicyclo[2.2.2]octane are orthorhombic, a = 8.0732(7), b = 11.8499(10), c = 31.679(2) Å, Z = 8, space group Pbca, and those of N-(4-nitrophenylmethylidene)-5-methyl-2-phenyl-1,3-dioxa-2-bora-5-cyclohexaneamine N-oxide are monoclinic, a = 6.1873(6), b = 23.206(2), c = 11.3081(11) Å, β = 92.326(5)°, Z = 4, space group P21/n. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.041 and 0.036 for 943 and 1679 reflections with I ≥ 3σ(I), respectively. Both compounds are condensation products of bis(hydroxyalkyl)nitrones and phenylboronic acid. 3-(Phenyl-methylidene)-4-methyl-1-phenyl-2,6,7-trioxa-3-azonia-1-boratabicyclo[2.2.2]octane was found to possess a bicyclic structure resulting from intramolecular O → B coordination (O—B = 1.604(7) Å) and is the first such bicyclic boron compound to be structurally characterized. In N-(4-nitrophenylmethylidene)-5-methyl-2-phenyl-1,3-dioxa-2-bora-5-cyclohexaneamine N-oxide, which has weakened nitrone basicity, the O → B interaction does not occur, resulting in a monocyclic system incorporating a trigonal planar boron atom.

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. 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.

Structural studies of organoboron compounds. XII. Crystal and molecular structures of (acetylacetonato)diphenylboron and (tropolonato)diphenylboron

1982 ◽  
Vol 60 (23) ◽  
pp. 2957-2964 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Chelate Ring ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
The Mean

There are two crystalline modifications of (acetylacetonato)diphenylboron: triclinic, a = 8.3557(8), b = 9.3519(8), c = 9.6103(9) Å, α = 96.094(5), β = 94.904(6), γ = 93.489(6)°, Z = 2, space group [Formula: see text], and monoclinic, a = 11.6329(11), b = 17.1628, c = 7.6542(6) Å, β = 97.669(4)°, Z = 4, space group P21/c. Crystals of (tropolonato)diphenylboron are monoclinic, a = 12.1596(5), b = 10.2614(4), c = 12.4883(6) Å, β = 100.965(2)°, Z = 4, space group P21/c. All three structures were solved by direct methods and were refined by full-matrix least-squares procedures to R values of 0.046, 0.041, and 0.035 for 2465, 2124, and 1722 reflections with I ≥ 3σ(I) respectively. Each structure consists of discrete molecules containing tetrahedrally coordinated boron atoms, both the acetylacetonato and tropolonato moieties being delocalized and symmetric. The chelate rings in both forms of (acetylacetonato)-diphenylboron have distorted B-envelope conformations while the chelate ring in (tropolonato)diphenylboron is essentially planar. The mean B—O and B—C distances (corrected for libration) are: 1.543(4) and 1.605(4) Å in triclinic, 1.533(3) and 1.607(4) Å in monoclinic (acetylacetonato)diphenylboron, and 1.555(11) and 1.605(6) Å in (tropolonato)diphenylboron.

Structural studies of organoboron compounds. XVIII. Crystal and molecular structures of 2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan and 4-cyclohexyl-6-methyl-2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan

1983 ◽  
Vol 61 (11) ◽  
pp. 2493-2499 ◽  
Author(s):  
W. Kliegel ◽  
D. Nanninga ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Direct Methods ◽  
Coordination Complexes ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Anionic Ligand ◽  
Oxide Crystals

The crystal structures of 2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan, 6a, and 4-cyclohexyl-6-methyl-2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan, 6b, reported here represent the first crystallographic examples of coordination complexes of the anionic ligand derived from 2-hydroxypyridine N-oxide. Crystals of 6a are monoclinic, a = 11.5210(13), b = 10.2860(8), c = 12.7354(15) Å, β = 101.878(5)°, Z = 4, space group P21/c; and those of 6b are monoclinic, a = 8.5047(8), b = 15.6603(14), c = 16.0501(18) Å, β = 104.776(5)°, Z = 4, space group P21/n. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.039 and 0.042 for 1440 and 1750 reflections with I ≥ 3σ(I), respectively. Both molecules feature tetrahedrally coordinated boron atoms incorporated into five-membered OBOCN chelate rings which have B-envelope conformations. The observed molecular geometries indicate that the ligand may be classed as a hybrid of the 2-hydroxypyridine N-oxide and 1-hydroxy-2-pyridinone tautomers of the parent alcohol. Important bond lengths (corrected for libration) are: O—B = 1.557(3)−1.580(3), mean C—B = 1.600(4), C—O = 1.316(3), and N—O = 1.389(3) Å.

Structural studies of organoboron compounds XXIII: preparation and crystal and molecular structures of 2,2-diphenyl-1,3-dioxa-4a- azonia-2-borata-1,2,3,4-tetrahydronaphthalene and 4,4-diphenyl-3-oxa-1-aza-4a-azonia-4-borata-1,2,3,4-tetrahydronaphthalene

1986 ◽  
Vol 64 (3) ◽  
pp. 507-513 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
D. Nanninga ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Pyridine Ring ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Analogous Structure ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Ring Nitrogen ◽  
Ring Nitrogen Atom

Details of the synthesis, physical properties, and the crystal molecular structures of 2,2-diphenyl-1,3-dioxa-4a-azonia-2-borata-1,2,3,4-tetrahydronaphthalene, 5, and 4,4-diphenyl-3-oxa-1-aza-4a-azonia-4-borata-1,2,3,4-tetrahydronaphthalene, 9, are reported. Crystals of 5 are monoclinic, a = 9.972(1), b = 11.848(1), c = 13.561(2) Å, β = 106.231(5)°, Z = 4, space group P21/c and those of 9 are orthorhombic, a = 20.676(1), b = 15.4199(9), c = 9.7533(4) Å, Z = 8, space group Pbca. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to R values of 0.036 and 0.045 for 1060 and 1700 reflections with I ≥ 3σ(I) respectively. Compound 5 has the expected cyclic B,N-betaine structure, resulting from N-aklylation of 2(1H)-pyridone with formaldehyde followed by reaction with (Ph2B)2O. The aza analog, however, does not have the analogous structure. The alkylation of 2-aminopyridine with formaldehyde in the presence of (Ph2B)2O yields 9, derived from alkylation of the amine rather than the pyridine ring nitrogen atom.

Synthesis of C-aryl-N-(2-hydroxyphenylmethyl)-nitrones and their reaction with diphenylborinic or carboxylic acid derivatives. Crystal and molecular structures of a free nitrone ligand and its diphenyl–boron chelate

1997 ◽  
Vol 75 (12) ◽  
pp. 1830-1843 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Carboxylic Acid ◽  
Electron Distribution ◽  
Direct Methods ◽  
Molecular Structures ◽  
State Structure ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
New Type ◽  
Boron Chelate ◽  
Diphenylboron Chelate

The syntheses of a number of aromatic aldonitrones of N-(2-hydroxyphenylmethyl)hydroxylamine and their subsequent reactions with diphenylborinic or carboxylic acid derivatives are reported. Crystals of 8-(4-dimethylaminophenylmethylene)-6,6-diphenyl-5,7-dioxa-8-azonia-6-borata-5H-6,7,8,9-tetrahydrobenzocycloheptene, 2b, are triclinic, a = 10.6802(8), b = 11.1809(4), c =10.1520(3) Å, α = 105.847(3)°, β = 92.567(4)°, γ = 84.610(5)°, Z = 2, space group PĪ, and those of C-(4-dimethylaminophenyl)-N-(2-hydroxyphenylmethyl)nitrone, 6e, are monoclinic, a = 12.2319(8), b = 7.071(1), c = 17.2005(9) Å, β = 107.520(4)°, Z = 4, space group P21/a. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.035 and 0.032 (Rw = 0.036 and 0.032) for 3379 and 1800 reflections with I ≥ 3σ(I), respectively. Compound 2b is representative of a new type of heterocyclic B,N-betaine. The solid state structure of 6e (the precursor to 2b) shows that only small topological changes, but significant changes in the electron distribution, occur upon the formation of the diphenylboron chelate. Keywords: aromatic aldonitrones, organoboron compounds, crystal structures.

C-(2-Hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones as regioselective bidentate ligands in boron chelate formation. Crystal and molecular structures of a diphenylboron complex and its parent ligand

1998 ◽  
Vol 76 (7) ◽  
pp. 1082-1092 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J Rettig ◽  
James Trotter
Keyword(s):  
Direct Methods ◽  
Acid Anhydride ◽  
Molecular Structures ◽  
Bidentate Ligands ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Chelate Formation ◽  
Boron Chelate ◽  
Parent Ligand

The C-(2-hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones 5 are synthesized by the condensation of variously substituted salicylaldehydes with N-(2-hydroxyphenylmethyl)-hydroxylamine. These nitrones react with diphenylborinic acid anhydride to form seven-membered diphenylboron chelates 6. Crystals of C-(4-diethylamino-2-hydroxyphenyl)-N-(2-hydroxyphenylmethyl)nitrone, 5d, are monoclinic, a = 6.911(2), b = 10.663(2), c = 22.951(1) Å, β = 97.33(1)°, Z = 4, space group P21/n, and those of 4-dimethylamino-8-(2-hydroxyphenylmethyl)-6,6-diphenyl-5,7-dioxa-8-azonia-6-borata-6,7-dihydro-5H-benzocycloheptene-ethanol, 6d·EtOH, are monoclinic, a = 9.069(2), b = 29.881(1), c = 11.1883(6) Å, β = 109.426(9)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.032 and 0.039 (R w = 0.031 and 0.036) for 2510 and 4162 reflections with I > 3σ(I), respectively. Key words : C-(2-hydroxyaryl)-N-(2-hydroxyphenylmethyl)nitrones, organoboron compounds, crystal structures.

Structural studies of organoboron compounds. XXXIII. 4,4-Dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclohexaneand 3,3-dimethyl-2-phenoxy-2-phenyl-1-oxa-3-azonia-2-boratacyclopentane

1989 ◽  
Vol 67 (5) ◽  
pp. 933-940 ◽  
Author(s):  
Eckardt Ebeling ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Physical Properties ◽  
Crystal Structures ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Boron Compounds ◽  
Organoboron Compounds ◽  
Thermally Induced ◽  
Full Matrix ◽  
Space Group

Details of the syntheses, physical properties, and crystal structures of the title compounds are reported. Crystals of 4,4-dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclohexane, 3, are monoclinic, a = 6.512(1), b = 15.765(2), c = 14.342(4) Å, β = 93.170(7)°, Z = 4, space group Pn, and those of 3,3-dimethyl-2-phenoxy-2-phenyl-1-oxa-3-azonia-2-boratacyclopentane, 4, are orthorhombic, a = 13.5829(8), b = 16.940(1), c = 6.3181(4) Å, Z = 4, space group P21212. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.034 and 0.034 for 1974 and 1478 reflections with I ≥ 3σ(I), respectively. The molecular structures are discussed in terms of the thermally-induced 1,2-migration of B-substituents by which 3 is converted to 4. Keywords: crystal structures, boron compounds, organoboron compounds.

Aromatic aldonitrones of 2-(hydroxyamino)benzyl alcohol and their cyclic isomers. Crystal and molecular structures of a 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine, a boron chelate, and its parent nitrone ligand

1998 ◽  
Vol 76 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Benzyl Alcohol ◽  
Crystal Structures ◽  
Direct Methods ◽  
Molecular Structures ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Independent Molecules ◽  
Boron Chelate

The synthesis of a series of C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 5 (that can also exist under certain conditions as isomeric 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, 8), via 2-(hydroxyamino)benzyl alcohol, 4, and their subsequent reactions with oxybis(diphenylborane), (Ph2B)2O, leading to the 5-(arylmethylene)-7,7-diphenyl-6,8-dioxa- 5-azonia-7-borata-5H-6,7,8,9-tetrahydrobenzocyclo- heptenes 6 are described. Crystals of 1-hydroxy-2- (4-methoxyphenyl)- 1,2-dihydro-4H-3,1-benzoxazine, 8b, are monoclinic, a = 9.379(2), b = 10.699(2), c = 12.9392(7) Å, β = 99.916(2)°, Z = 4 (two independent molecules), space group Pa; those of C-[4-(dimethylamino)phenyl]-N-[(2-hydroxymethyl)phenyl]nitrone, 5c, are monoclinic, a = 7.687(1), b = 7.891(1), c = 11.5053(9) Å, β = 92.781(9)°, Z = 2, space group P21; and those of 5-[4-(dimethylamino)phenylmethylene]-7,7-diphenyl-6,8-dioxa-5-azonia-7-borata-5H-6,7,8,9- tetrahydro-benzocycloheptene, 6a, are monoclinic, a = 10.771(1), b = 13.1057(9), c = 16.8724(7) Å, β = 90.005(5)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R(F2) = 0.120 (Rw(F2) = 0.135) for all 3149 reflections (R(F) = 0.071, Rw(F) = 0.063 for 1500 reflections with I >3 σ (I)) for 8b and R(F) = 0.035 and 0.036 (Rw(F) = 0.031 and 0.038) for 1071 and 3594 reflections with I >3 σ (I), respectively, for 5c and 6a. Compound 8b is the first structurally characterized 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine derivative and 6a features a relatively rare seven-membered boron-containing heterocycle.Key words: C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, organoboron compounds, crystal structures

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