Abstract:peri‐Überbrückung bei Naphthalin durch ein Boratom bewirkt in dem Naphtho[l,8‐bc]boret 1 eine starke Abweichung der sp2‐Bindungswinkel an C1 und C8 vom Idealwert. Die daraus resultierende Ringspannung prägt die Chemie von 1: Bei der Umsetzung mit elektronenarmen Borverbindungen EX3 wird eine unerwartete Ringexpansion zu 2 (X = CI, Br, OEt) beobachtet.
“…The bis(amino)naphthalenediyl group is bonded in an N,NЈ-chelating fashion to the boron atom which has a trigonal-planar geometrical environment. The B-N bond lengths [1.424(4) Å and 1.419(4) Å] are in the usual range for B-N compounds, [25] comparable to the B-N bonds found in 1,3,2-diazabora . [26] Compound 5 exists in the solid state as a stable monomer due to the sterically demanding N(SiiPr 3 ) 2 groups and also due to the interaction of the vacant p-orbital at the tin atom with the unshared electron pairs of the trigonal-planar nitrogen atoms.…”
Section: Molecular Structures Of Compounds 2 4 Andmentioning
The reaction of the diaminonaphthalene dilithium salt (THF) 2 Li 2 [(NSiMe 3 ) 2 C 10 H 6 ] with BX 3 (X = Cl, Br) in hexane provides the monomeric compounds BX[(NSiMe 3 ) 2 C 10 H 6 ] [3 (X = Cl), 4 (X = Br)] with a tricoordinate boron atom. Attempts to reduce 3 and 4 with lithium, sodium, potassium or sodium/ potassium alloy with the intention to isolate a boranide resembling a carbene were unsuccessful. However, the diaminonaphthalene dilithium salt (THF) 2 Li 2 [(NSi-iPr 3 ) 2 C 10 H 6 ] (2) reacts with SnCl 2 in THF to provide the carbene analog 5. Compounds 2, 3 and 5 were characterized by single-crystal
“…The bis(amino)naphthalenediyl group is bonded in an N,NЈ-chelating fashion to the boron atom which has a trigonal-planar geometrical environment. The B-N bond lengths [1.424(4) Å and 1.419(4) Å] are in the usual range for B-N compounds, [25] comparable to the B-N bonds found in 1,3,2-diazabora . [26] Compound 5 exists in the solid state as a stable monomer due to the sterically demanding N(SiiPr 3 ) 2 groups and also due to the interaction of the vacant p-orbital at the tin atom with the unshared electron pairs of the trigonal-planar nitrogen atoms.…”
Section: Molecular Structures Of Compounds 2 4 Andmentioning
The reaction of the diaminonaphthalene dilithium salt (THF) 2 Li 2 [(NSiMe 3 ) 2 C 10 H 6 ] with BX 3 (X = Cl, Br) in hexane provides the monomeric compounds BX[(NSiMe 3 ) 2 C 10 H 6 ] [3 (X = Cl), 4 (X = Br)] with a tricoordinate boron atom. Attempts to reduce 3 and 4 with lithium, sodium, potassium or sodium/ potassium alloy with the intention to isolate a boranide resembling a carbene were unsuccessful. However, the diaminonaphthalene dilithium salt (THF) 2 Li 2 [(NSi-iPr 3 ) 2 C 10 H 6 ] (2) reacts with SnCl 2 in THF to provide the carbene analog 5. Compounds 2, 3 and 5 were characterized by single-crystal
“…In the naphthalene derivatives 4 and 5 the Ti-C9 distance in 4 [2.442(7) Å)] 15 and the B-C9 distance in 5 [2.045(5) Å)] 16 are shorter than the sum of the van-der-Waals radii, and it may seem that a ptC is present (especially in the case of 4). However, on the basis of orbital symmetry there is no bonding interaction between Ti or B and the bridging carbon atom C9.…”
Section: Planar-tetracoordinated Carbon Incorporated In a P System Co...mentioning
Over the past years the number of examples of compounds containing a planar-tetracoordinate carbon atom has increased. However, the presence of a carbon atom with a 360°s um of angles does not imply that the species is a derivative of planar methane; there must be an appropriate electronic stabilization. In the case of complexes 21a and 21b the central carbon atom is indeed stabilized by s-donors and pacceptors, as required for planar methane.
“…It should be noted that 1,4-additions of boron species to naphthalene , by one or two boron atoms are well documented. Likewise, naphthalene species that are diborylated in the 1,8-positions are obtained from the 1,8-dilithiated − or the 1,8-dimercurated , precursors. …”
Bis(diorganylamino)dihalo-1,3-diboroxanes 1
result from the controlled hydrolysis of
(diorganylamino)dihaloboranes substituted with bulky dialkyl- or
alkylarylamino groups.
Dehalogenation with sodium/potassium alloy gives
1,4-dioxa-2,3,5,6-tetraborinanes 3 and,
in the case of the di(s-butyl)amino groups, the
corresponding oxadiborirane 4. If the
dehalogenation is carried out in the presence of bi- or tricyclic
aromatic compounds, addition
of a B(NR2)OB(NR2) moiety is
observed, and the corresponding
1,3-(1,2-dihydronaphthaline-1,2-diyl)diboroxane (5),
1,3-(9,10-dihydroanthracene-9,10-diyl)diboroxane
(6), and 1,3-(9,10-dihydrophenanthrene-9,10-diyl)diboroxane (7)
species are obtained. The compounds were
characterized by NMR spectroscopy (1H, 11B,
13C), MS (EI and FI), and elemental analyses.
X-ray crystal structure determinations are presented for
1a, 3a, 5a, and 6b.
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