Chemical Shifts and Coupling Constants for Boron-11 and Phosphorus-31

369 Pages·1997·8.079 MB·English

by  R. R. Gupta (auth.), R. R. Gupta, M. D. Lechner (eds.)

1 Introduction 1
1 Introduction
The phenomenon of nuclear magnetic resonance (NMR) is based on magnetic properties of nuclei and
therefore they are included here.
1.1 Magnetic properties of nuclei
All nuclei carry a charge and in some nuclei this charge spins on the nuclear axis generating a magnetic
field along the axis. These nuclei behave as tiny bar magnets. The magnetic properties of a nucleus can be
specified in terms of spin number I (I = 0, 1/2, 1, 3/2, 2, 5/2, .....) and the magnetic moment µ of the
nucleus. The magnetic moment of the nucleus is proportional to the spin angular momentum and is
expressed by Eq. (1):
µ (cid:1)[I(I+1)]½ h/(2(cid:3)(cid:4)(cid:5) (1)

µ = (cid:1) [I(I+1)]½ h/(2(cid:3)(cid:4)(cid:5) (2)

where (cid:1) is a proportionality constant known as gyromagnetic or magnetogyric ratio (differing for each
nucleus and essentially measures the strength of nuclear magnets). [I(I+1)]½ h/(2(cid:3)(cid:4) is the spin angular

momentum in terms of the spin number I, h is Planck’s constant (6.626.10(cid:1)34 J/s).
However, the measurable component of the angular momentum is Ih/(2(cid:3)(cid:4) and Eq. (2) can be reduced

to Eq. (2a):
g hI
(cid:2) (cid:6) (cid:7) (cid:8)2a(cid:4)
2p
The magnetic moment µ can be also expressed in terms of the Bohr magneton (or nuclear magneton)
by Eq. (3):
µ = g B [I(I+1)]½ h/(2(cid:3)(cid:4)(cid:5) (3)
n n
where g is known as the nuclear g-factor (which is determined experimentally). B is the nuclear
n n
magneton defined as eh/(4(cid:3)m) (e = electronic charge, m = mass of proton) = 5.05.10(cid:1)24 erg/G.

Each proton and neutron has its own spin and the spin number. I is the resultant of these two spins. If
the sum of protons and neutrons (i.e. mass number) is odd, I is half-integer (I =1/2, 3/2, 5/2, ...), if both
protons and neutrons are even-numbered, I is zero (I = 0 denotes no spin) and if the sum is even, I is
integer (I = 1, 2, 3, 4 ...). The magnetic properties of some NMR nuclei are summarized in Table 1. Nuclei
with I > 0 may be called magnetic as they develop the magnetic fields along the axis of spins and give rise
to the phenomenon of nuclear magnetic resonance. Such nuclei do not simply possess magnetic dipoles,
but rather possess electric quadrupoles (it measures the electric charge distribution within a nucleus when
it possesses non(cid:9)spherical symmetry) and interact with both, magnetic and electric gradients. The relative
importance of the two effects is related to their magnetic moments and electric quadrupole moments.
Landolt(cid:1)Börnstein
New Series III/35A
2 1 Introduction
1.2 Spinning nuclei in magnetic fields
A spinning nucleus generates a magnetic moment and when placed in an uniform magnetic field H it tends
to align itself with the field. Unless the axis of the nuclear magneton is oriented exactly parallel or
antiparallel to the magnetic field, a certain force is exerted by the applied field. Because the nucleus is
spinning, the effect is that its rotational axis draws out a circle perpendicular to the external field (Fig. 1).
This motion is called precession. The precessional angular velocity of a spinning top is known as Larmor
frequency (cid:3) which is proportional to the applied field and can be expressed by Eq. (4) (the gyromagnetic
ratio (cid:1) is equal to the ratio of the angular precessional frequency and the applied field):
(cid:3) = (cid:1) H. (4)
Fig. 1. Spinning nuclei in magnetic fields
Table 1. Magnetic properties of NMR nuclei.
Isotope Natural Spin Magnetogyric Magnetic Electrical
abundance number ratio moment quadrupole
% I (cid:1) µ moment
rad/G Bohr magneton e.10(cid:1)24 cm2
1H 99.9844 1/2 26753 2.79270 (cid:9)
1
2H 0.156 1 4107 0.85738 2.77.10(cid:1)3
1
3H (cid:9) 1/2 (cid:9) 2.9788 (cid:9)
1
10B 18.83 3 (cid:9) 1.8006 0.111
5
11B 81.17 3/2 (cid:9) 2.6880 3.55.10(cid:1)2
5
13C 1.108 1/2 6728 0.70216 (cid:9)
6
14N 99.635 1 (cid:9) 0.40357 2.10(cid:1)2
7
15N 0.365 1/2 (cid:9)2712 (cid:9)0.28304 (cid:9)
7
17O 0.037 5/2 (cid:9)3628 (cid:9)1.8930 (cid:9)4.10(cid:1)3
8
19F 100.00 1/2 25179 2.6273 (cid:9)
9
29Si 4.70 1/2 (cid:9)5319 (cid:9)0.55477 (cid:9)
14
31P 100.00 1/2 10840 1.1305 (cid:9)
15
33S 0.74 3/2 2054 0.64274 (cid:9)5.5.10(cid:1)2
16
35S (cid:9) 3/2 (cid:9) 1.00 4.5.10(cid:1)2
16
35Cl 75.40 3/2 2627 0.82089 (cid:9)7.97.10(cid:1)2
17
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1 Introduction 3
Table 1. (cont.)
Isotope Natural Spin Magnetogyric Magnetic Electrical
abundance number ratio moment quadrupole
% I (cid:1) µ moment
rad/G Bohr magneton e.10(cid:1)24 cm2
37Cl 24.60 3/2 2184 0.68329 (cid:9)6.21.10(cid:1)2
17
79Br 50.54 3/2 0.34 2.0991 (cid:9)
35
81Br 49.46 3/2 0.28 2.2626 (cid:9)
35
127I 100.00 5/2 0.75 2.7937 (cid:9)
53
183W 14.40 1/2 (cid:9) 0.177 (cid:9)
74
The precessional frequency (cid:4) can be expressed by Eq. (5):
(cid:3) (cid:10)(cid:8)2(cid:3)(cid:4) = (cid:4) or (cid:3) = 2(cid:3)(cid:4) = (cid:1) H, (5)
(cid:4) = (cid:1) H/(2(cid:3)(cid:4)(cid:7) (cid:8)(cid:11)(cid:4)
The Larmor frequency is such that a projection of the angular momentum on the direction of H always
assumes whole multiple of h/(2(cid:3)(cid:4) and as such, not all possible precession “cones” occur, only some
selected ones. The number of these possible alignments is 2I+1 for spin I in the direction of magnetic
field. These 2I+1 orientations are quantized in the direction of magnetic field and the absorbable
component m of the spin I can be expressed by Eqs. (7) and (8) for half-integer and integer spins,
respectively:
m = I, I(cid:9)1, I(cid:9)2, ..., 1/2, (cid:9)1/2, ..., (cid:9)(I(cid:9)2), (cid:9)(I(cid:9)1), (cid:9)I, (7)
m = I, I(cid:9)1, I(cid:9)2, ..., 1, 0, (cid:9)1, ..., (cid:9)(I(cid:9)2), (cid:9)(I(cid:9)1), (cid:9)I. (8)
In each case there are 2I+1 values of m. Each orientation is associated with a different energy level E
and can be expressed by Eq. (9):
g h
E = (cid:9) µH or E = (cid:9) H m . (9)
2p
This type of splitting of energy levels in magnetic fields for a nucleus (I > 0) is called nuclear Zeeman
splitting.
1.3 Theory of nuclear resonance
The basis of nuclear magnetic resonance is to induce transitions between the nuclear Zeeman energy
levels. Such transitions are affected by placing an alternating field H perpendicular to the applied field H
a
in such a way that frequency can be altered conveniently. Selection rules permit such transitions between
energy levels 2 and 1 that m (cid:9) m = (cid:12)m = ± 1 i.e. (cid:12)m = +1 when energy is absorbed (transition is from
2 1
lower to higher energy level) and (cid:12)m = (cid:9)1 when energy is emitted (transition from higher to lower energy
level). Such transitions from E to E energy levels can be expressed by Eq. (10):
2 1
g h g h g h
(cid:12)E = E (cid:9) E =- ( Hm- Hm ) = (cid:9) H(m (cid:9) m ). (10)
2 1 2p 2 p2 1 2p 2 1
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New Series III/35A
4 1 Introduction
According to selection rules of quantum mechanics, m (cid:9) m = ± 1 depending on whether energy is
2 1
absorbed or emitted, Eq. (10) is reduced to Eq. (11):
g hH
(cid:12)E = ± . (11)
2p
When the frequency of electromagnetic radiation necessary to induce a transition from one nuclear
spin state to another is exactly equal to the precessional frequency of spinning nucleus, they are in
resonance and the phenomenon of resonance occurs. Thus nuclear resonance (absorption or emission of
energy) occurs when a magnetic nucleus (I > 0) is placed in an uniform magnetic field H and subjected to
electromagnetic radiation of appropriate frequency matching to the precessional frequency of spinning.
Under these conditions the frequency of electromagnetic radiation causing resonance can be expressed by
Eq. (12):
g hH g H
(cid:12)E = h (cid:4) = , or (cid:4) = . (12)
2p 2p
g H
Eq. (12) also exhibits that the precessional frequency (cid:4) is .
2p
Eq. (12) correlating electromagnetic frequency causing nuclear resonance with magnetic field strength
is the basis of NMR spectroscopy and from this equation the electro-radiation frequency causing the
resonance for various field strengths can be calculated. Precessional frequencies for some nuclei at various
field strengths are summarized in Table 2.
Table 2. Precessional frequencies as a function of field strength
(cid:4) [MHz]
Nucleus H [kG] 14 21 23 47 71 94 117
1H 60.0 90.0 100.0 200.0 300.0 400.0 500.0
1
2H 9.2 13.8 15.3 30.7 46.0 61.4 76.8
1
3H 63.6 95.4 104.5 213.5 322.5 426.9 531.4
1
10B 6.4 9.61 10.5 21.5 32.5 43.0 53.6
5
11B 19.2 28.7 32.0 64.2 96.9 128.8 159.8
5
13C 15.1 22.6 25.1 50.3 75.5 100.8 125.7
6
14N 4.3 6.5 7.2 14.5 21.7 29.1 36.1
7
15N 6.1 9.1 10.1 20.3 30.4 40.7 50.7
7
17O 8.1 12.2 13.6 27.1 40.7 54.5 67.8
8
19F 56.5 84.7 94.1 188.2 288.2 377.6 470.5
9
29Si 11.8 17.8 19.5 39.8 60.1 79.5 99.0
14
31P 24.3 36.4 40.5 81.0 121.5 162.8 202.0
15
33S 4.6 6.9 7.5 15.4 23.2 30.7 38.2
16
35S 7.1 10.7 11.7 23.9 36.1 47.8 59.5
16
35Cl 5.8 8.7 9.6 19.6 29.6 39.2 48.8
17
37Cl 6.9 10.3 11.3 23.0 34.7 46.0 57.3
17
79Br 14.9 22.4 24.5 50.1 75.7 100.3 124.8
35
81Br 16.1 24.2 26.5 54.0 81.6 108.1 134.5
35
127I 11.9 17.9 19.6 40.0 60.5 80.1 99.7
53
183W 2.5 3.67 4.0 8.2 12.4 16.5 20.5
74
Landolt(cid:1)Börnstein
New Series III/35A
1 Introduction 5
1.4 Chemical shift
g H
The fundamental NMR Eq. (12), (cid:4) = , exhibits that a single peak should be obtained from the
2p
interaction of radiofrequency energy and the magnetic field on a nucleus as (cid:1) is characteristic for a
nucleus. However, the nucleus is shielded by an electron cloud whose density varies with the environment.
This variation gives rise to different absorption positions. Under the influence of the applied magnetic
field electrons circulate and generate their own magnetic field opposing the applied field and cause a
shielding effect. The magnitude of the induced field is proportional to the magnetic field. The effective
magnetic field experienced by the nucleus is changed by this small local field (cid:5)H (due to electronic
circulation), such that H = H (cid:9) (cid:5)H. A nucleus in different environments is shielded by the
effective
circulation of surrounding electrons to different extents. Different values of (cid:5)H, each depending on the
magnitude of the applied field H are obtained for the nucleus. Because the strength of the applied
magnetic field cannot be determined to the required degree of accuracy, the absolute position of
absorptions cannot be obtained directly from the instrument. However, the relative position of absorption
can readily be obtained with an accuracy of ± 1 Hz. The separation of resonance frequencies of a nucleus
in different structural environments from an arbitrarily chosen standard is termed as chemical shift. A plot
of the chemical shifts (frequencies of absorption peaks) versus the intensities of absorption peaks, which
by integration provides the number of nuclei, constitutes a NMR spectrum. The chemical shift is
symbolized by (cid:6) (delta) and is measured in ppm (parts per million) according to Eq. (13):
n -n
(cid:6) (in ppm) = 106 . s r , (13)
n
r
where (cid:4) and (cid:4) are the resonance frequencies in Hz of the sample s and the reference substance r,
s r
respectively, at constant field H = H = H.
r s
Since field and frequency are linearly related, Eq. (13) can be transformed to Eq. (14):
H - H
(cid:6) (in ppm) = 106 . r s , (14)
H
r
where H and H refer to the fields at resonance for the sample s and the reference substance r,
s r
respectively, at constant frequency (cid:4) = (cid:4) = (cid:4).
r s
The chemical shift in Hz is directly proportional to the applied field H and therefore to the applied
frequency. It is dependent on diamagnetic shielding induced by the applied field. It is the ratio of the
necessary change in field to the reference field or the necessary change in frequency to the reference
frequency and hence a dimensionless number. To spread out chemical shifts i.e. to increase separation of
resonance signals, a high magnetic field is applied which constitutes high resolution NMR spectroscopy.
Chemical shifts are also expressed in an alternative scale, (cid:7), which is related to (cid:6) by Eq. (15):
(cid:7) = 10.00 (cid:9) (cid:6) . (15)
High values of chemical shifts ((cid:6) in ppm(cid:4) correspond to high frequency shifts (down field or low field)
due to deshielding; and low values correspond to low frequency shifts (upfield or high field) due to
shielding.
Landolt(cid:1)Börnstein
New Series III/35A
6 1 Introduction
1.5 Coupling constant
The position of the resonance signal of a nucleus A depends on its magnetic environment: part of its
magnetic environment is the nearby nucleus B which itself is magnetic and nucleus B can either have its
nuclear magnet aligned with nucleus A or opposed to nucleus A. In this way nucleus B can either increase
the net magnetic field experienced by nucleus A (B aligned) or decrease it (B opposed); in fact it does
both. The two spin orientations of B create two different magnetic fields around nuclei A. As such nuclei
A comes to resonance twice and gives rise to a doublet in the NMR spectrum. Similarly nucleus A is
magnetic having two spin orientations and creates two magnetic fields around nucleus B. Nucleus B
comes to resonance twice and gives rise to a doublet in the NMR spectrum. The mutual magnetic
influence between nuclei A and B is transmitted via the electrons in the intervening bonds (not through
space). The electron-coupled spin interaction operates strongly through one or two bonds, less strongly
through three bonds and weekly through more bonds. A signal can split into a doublet or multiplet
depending upon the number of interacting neighbour nuclei. Splitting of the spectral lines arises due to
coupling interactions between neighbour nuclei and is related to the number of possible orientations that
neighbour nuclei can adopt. Splitting arises because of spin-spin interactions or coupling and this
phenomenon is known as spin-spin splitting or spin-spin coupling. Spin-spin splitting (separation of a
resonance signal) is expressed in terms of the coupling constant J. It is a measure of the interaction of
nuclei interacting through intervening electrons. It is independent of the applied magnetic field and is
expressed in units of frequency (Hz). Generally, J is expressed as, 1J , 2J ... to indicate that nuclei A
AB AB
and B are interacting through 1, 2, 3.... bonds.
1.6 Organization of Data
This volume contains chemical shifts (cid:6) (in ppm) and coupling constants J (in Hz) for boron-11 and
phosphorus-31 nuclei. For each nuclei the arrangement of compounds is based on their gross formulae
arranged according to Hill's system i.e. in alphabetical order of elements except for compounds containing
carbon. Compounds which contain carbon have been arranged considering carbon and hydrogen on
priority in ascending order followed by the alphabetical arrangement for the other atoms present in the
molecule. Chapters 2 and 3 deal with NMR data for 11B and 31P, respectively. Sections 2.1, 2.2, and 2.3
(chapter 2) and sections 3.1, 3.2, and 3.3 (chapter 3) dealing with chemical shifts are printed in this
subvolume. Sections 2.4 and 2.5 (chapter 2) and sections 3.4 and 3.5 (chapter 3) dealing with coupling
constants are only provided on the CD-ROM included in this book. Additionally all data printed in this
subvolume are also provided on the CD-ROM.
Landolt(cid:1)Börnstein
New Series III/35A
2.1 Introduction for 2 7
2.1 Introduction for 2
Boron- 11 NMR has been studied extensively since the discovery of NMR in 1946. Over the last
four decades several thousand boron compounds with a wide variety of basic boron skeletons have been
prepared and in this immense field of boron chemistry, 11B NMR spectroscopy has emerged as the fastest
and the most reliable physical method for structural determination [87Her2, 84Wra1, 78Nöt, 69Eat]. Boron
has two naturally occurring isotopes 10B and 11B. Of these 11B is most commonly studied due to its higher
natural abundance (80.4%), strong signal (better sensitivity ), fairly large spectrum range d of about
220 ppm [83Kid], optimum coupling (magnetogyric ratio, g = 8.582·107 exactly three times higher than the
10B isotope), smaller electric quadrupole moment (0.0355·10- 28 m2), reasonable line width at half height
h (30- 60Hz) [73Clo] and short relaxation times (10- 50 ms) [78Wei, 78Wri, 76Odo, 69All]. The 10B nucleus
1/2
in contrast is present in lower natural abundance (19.58%), has a three times higher quadrupole moment
which broadens its NMR signal and is observed at lower resonance frequency.
Boron forms both three- coordinated and four- coordinated compounds [89Gre, 75Ona]. As
for other nuclei [78Har], the 11B chemical shift depends on the antipodal effect [91Büh, 91Sch, 76Her], the
coordination number [70Wil], the electron density [64Pop, 50Ram], the hybridisation and ring current as
well as on the geometry of the boron atoms [90Kut, 76Kro]. Compounds with a boron atom in
coordination number three (sp2 hybridisation, trigonal planar envionment) are usually boranes BX and
3
are frequently found to be strongly deshielded appearing in the chemical shift range of d = 90 to
- 10 ppm. Compounds containing a boron atom with coordination number four (sp3 hybridisation,
-
tetrahedral or distorted tetrahedral environment) are borates BX or borane adducts (BX·L) and are
4 3
usually shielded in comparison to boranes due to the reduction of paramagnetic contributions and give
shifts in the range of d = 10 to - 130 ppm [83Kid]. The magnitude of substituent effects on 11B chemical
shifts depends on the local symmetry and on the coordination number of the boron atoms.
The unique bonding properties of boron are evidenced by the vast variety of polyboranes,
carboranes, metallaboranes, etc. There is much chemical shift data for these compounds [92Her, 88Sie,
87Ken, 69Eat] but the assignments are quite complicated partly due to the changeable character of the
metal fragment in the metallaboranes [86Tei, 70Wil]. Application of 2D NMR techniques has proven
particularly successful in these cases [94Hol, 93Ree, 91Fon, 84Bur, 84Gri].
The relatively efficient relaxation pathway available to 10B and 11B isotopes by virtue of their
small quadrupole moments prevents extraction of useful structural information that can commonly be
obtained from well resolved coupling constants with spin ½ nuclei. Nevertheless many coupling constant

data have been reported for directly bonded nuclei [85Cor, 76Kro]. Hydrogen can form bridging and
terminal bonds with boron and these can be easily distinguished by observing coupling constants [76Ona];
couplings to terminal hydrogens occur in the range of 120- 190 Hz whereas coupling to bridge hydrogens
occur in the region of 30- 60 Hz. Coupling constants to other nuclei with spin ½ (J11BX) increase with
the increasing size of the coupled atom [92Bar, 90Oua, 77Fus]. The number of J coupling constants
B-B
reported are relatively few probably because the boron- boron couplings are never fully resolved due to
the presence of quadrupolar relaxed nuclei at both ends of the coupled spectrum [84And, 79Bac, 71Odo].
Similarly only few long range couplings nJ(11BX) (n > 1) have been reported for compounds in which
boron has a highly symmetric electronic environment [92Atc, 91Man2, 85Bec].
The major objective of this chapter has been to collate the enormous amount of information
on boron- 11 NMR parameters of a very large number of a variety of boron skeletons and present it in
Landolt-Börnstein
New Series III/35A
8 2.1 Introduction for 2
a form that can readily be retrieved and used. This article is somewhat different from those reported so
far [93Ree, 92Her, 88Sie, 88Wra, 87Ken, 83Kid, 82Sie, 79Tod, 79Wra, 78Nöt, 69Eat] in which although the
11B NMR data of organic and organometallic compounds of boron as well as those of polyboranes,
carboranes, and metallaboranes have each been reviewed separately several times, this appears to be the
first attempt to bring together the 11B NMR data of all these structurally different compounds. Presentation
of all such data exceeds the space available for this chapter and therefore while efforts have been made
to include the 11B NMR data of all different types of boron skeletons known, extensive repetition has been
avoided. Solid- state NMR work has also not been included, in spite of the fact that there are a number
of promising applications in borate glasses [94Duc, 94Sil], zeolites [92Sil], carbides [86Con], etc.
The gross formulae have been arranged according to the Hill system i.e. in case of compounds
not containing carbon, alphabetical order; otherwise the priority of elements is C, H, and then other
elements in alphabetical order. Salts ( M----- X+ or M+++++X----- ) have been represented as their prominent anions
(M ----- ) or cations (M+++++ ))))). In many cases, the spectrum in only the most readily available solvent is listed
due to space considerations. Temperature or pH dependence, if reported, is also indicated in this column.
A hyphen means solvent has not been quoted. All the chemical shifts are in d ppm relative to diethyl
ether/boron trifluoride ( Et O·BF ) with a positive sign indicating a shift to lower field (higher frequency).
2 3
The following constants for transformation of data reported with respect to other compounds have been
used. These are based on the values quoted by Nöth and Kid [78Nöt, 83Kid]:
Compound Shift from BF·EtO(ppm) Compound Shift from BF·EtO(ppm)
3 2 3 2
BF·MeO +0.7 B(OH) +18.8
3 2 3
BF +11.5 BCl +47.0
3 3
B(OMe) +18.1 B(CH) +86.2
3 33
Assignment of boron atoms has been referred to as B1 or 1B; B1 means boron atom No. 1 whereas
1B corresponds to integration equivalent to one boron atom. Wherever it is reported the half- width
h in Hz is cited in parentheses. As far as possible reference is made to the original literature. An attempt
1/2
has been made to reduce as much structural information as possible to a line form specially in cases
of polyboranes, carboranes and metallaboranes. More complex structures are shown in diagrams and the
following convention has been adopted :
B or BH H (terminal hydrogen)
t
C or CH or CMe H (bridging hydrogen)
b
Other elements
Landolt-Börnstein
New Series III/35A
2.1 Introduction for 2 9
ABBREVIATIONS
9-BBN - 9-Borabicyclo[3,3,1]nonyl, B
O
BCat - B-
O
Bipy - 2,2'-Bipyridine
Bn - Benzyl
BTMA - Benzyltrimethylammonium
Chx - Cyclohexyl
COD - 1,5-Cyclooctadiene
DACH - 1,2-Diaminocyclohexane
DBN - 1,5-Diazabicyclo[4,3,0]non-5-ene
Dib - Diisobutylene-2 (2,4,4-Trimethyl-2-pentene)
DMBA - N,N-Dimethylbenzylamine
DMLA - N,N-Dimethyllaurylamine
DMOA - N,N-Dimethyloctylamine
Dmpe - 1,2-Bis(dimethylphosphino)ethane
Dppe - 1,2-Bis(diphenylphosphino)ethane
HMTA - Hexamethyltetramine
Ipc - Isopinocamphyl
MeChx - Methylcyclohexane
Mes - Mesityl (2,4,6-Trimethylphenyl)
NBD - Norbornadiene
Phen - Phenanthroline
PPN - Bis(triphenylphosphine)nitrogen(1+) cation
Py - Pyridine
Pz - Pyrazolyl
QND - Quinuclidine,
N
TBA - Tetrabutylammonium
TED - Triethylenediamine
Thx - Thexyl (1,1,2-Trimethylpropyl)
TMED - N,N,N',N'-Tetramethylethylenediamine
TMP - 3,4,7,8-Tetramethyl-1,10-Phenanthroline
Landolt-Börnstein
New Series III/35A
10 2 Boron- 11 NMR
2.2 Table for 11B chemical shift d , downfield from BF .Et O. All measurements refer to room
3 2
temNpeor.atuGrer oisfs fnoortm sutlaated otheSrwolivseen.t ddddd [ppm] Ref.
No. Gross formula Solvent ddddd [ppm] Ref.
1 AlB H - - 32.8to- 37.1 84Man,78Nöt
3 12
2 AsB BiH CH COCH +15.2(B12),+13.5(B9) 90Lit
10 10 3 3
+6.6(B3,6),+5.6(B7,11),
- 1.7(B8,10),- 3.7(B4,5)
3 AsB H Sb DMF +14.2(B12),+12.3(B9) 92Her,79Lit
10 10
+3.0(B8,10),- 0.1(B4,5),
- 2.0(B7,11),- 3.5(B3,6)
-
4 AsB H CD COCD +7.3(B5),- 7.5(B2,3) 91Fon
10 12 3 3
(2D NMR) - 9.1(B8,11),- 15.1(B9,10),
- 22.1(B1),- 24.2(B4,6)
-
5 AsB H THF +7.9(B12),- 7.8(B7-11), 91Oua,87Han
11 11
- 8.9(B2-6)
CH Cl +6.3(1B),-8.6(10B) 91Oua,74Lit
2 2
-
6 As B H CD COCD +0.8(B9,11),- 1.1(B5,6), 91Fon
2 9 10 3 3
(2D NMR) - 7.7(B3),- 10.5(B2,4),
- 16.8(B10),- 27.0(B1)
7 As B H CD Cl +17.6(B9,12),+2.3(B3,6), 91Fon,86Tei,
2 10 10 2 2
(2D NMR) +0.5(B4,5,7,11),- 0.2(B8,10) 74Lit
8 BBrClF MeChx +31.9 71Lap
9 BBrH S CS +60.6to+56.2 88Azi,73Bou
2 2 2
10 BBrH P MeI - 26.0 73Rap
5
11 BBrI - +15.5 76Daz
2
MeChx +11.0 71Lap
12 BBr HS CS +61.5 88Azi
2 2
CS +49.8 73Bou
2
13 BBr H P MeI - 19.0 73Rap
2 4
14 BBr MeChx +38.7 71Lap
3
15 BBr H P MeI - 22.7 74Dra2
3 3
16 BBr - - - 23.0to- 26.0 92Atc,88Wra,78Nöt
4
17 BClF MeChx +19.8 71Lap
2
18 BClH P MeI - 19.0 73Rap
5
19 BCl HS MeI +55.0 73Bou
2
20 BCl H N Et O - 1.3 79Hu
2 4 2
21 BCl H P MeI - 6.0 73Rap
2 4
22 BCl MeChx +46.5 83Kid,71Lap
3
23 BCl F OP - - 3.0 69Ele
3 3
24 BCl H P MeI +1.7 74Dra2
3 3
25 BCl - - +4.5to+8.0 92Atc,88Wra,78Nöt
4
26 BCl N Si CCl +36.3 68Wan
13 2 4 4
27 BF H - +22.0 78Nöt
2
28 BF H N - - 3.6 73Tuc
2 4
29 BF MeChx +10.0 71Lap
3
30 BF H N CH CN - 0.9 65Hei
3 3 3
Landolt-Börnstein
New Series III/35A