Synthesis and X-ray Crystal Structures of Ga-substituted Distibenes [L(X)GaSb]2

Article abstract of DOI:10.1002/zaac.201800204

The reactions of two equivalents of LGa {L = HC[C(Me)N(2,6-iPr₂C₆H₃)]₂} with SbX₃ (X = Br, I, OEt) proceed with elimination of LGaX₂ and formation of Ga-substituted distibenes [L(X)GaSb]

Full text of DOI:10.1002/zaac.201800204

Journal of Inorganic and General Chemistry
DOI: 10.1002/zaac.201800204
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
Synthesis and X-ray Crystal Structures of Ga-substituted
Distibenes [L(X)GaSb]2
Julia Krüger,[a] Juliane Schoening,[a] Chelladurai Ganesamoorthy,[a] Lukas John,[a] Christoph Wölper,[a] and
Stephan Schulz*[a]
Dedicated to Prof. A. Filippou on the Occasion of his 60th Birthday
Abstract. The reactions of two equivalents of LGa {L
=
[L(X)GaSb]2 [X = Br (1), I (2), OEt (3)]. Compounds 1 to 3 were
HC[C(Me)N(2,6-iPr2C6H3)]2} with SbX3 (X = Br, I, OEt) proceed with characterized by heteronuclear NMR (1H, 13C), IR and UV/Vis spec-
elimination of LGaX2 and formation of Ga-substituted distibenes
troscopy, elemental analysis, and single-crystal X-ray diffraction.
Introduction
The interest in heavier main group element compounds con-
taining an element–element double bond received a tremen-
dous boost in the early 80ies of the last century, when West et
al.[1] and Joshifuji et al.[2] reported on the first compounds
containing Si=Si and P=P double bonds, respectively. Since
then, numerous main group element compounds of group 13
to 16 elements containing homoleptic or heteroleptic double
and triple bonds, which violate the so-called double bond
rule,[3] according to which the formation of π bonds is restric-
ted to elements of the second row of the periodic Table, have
been reported,[4] their bonding situation analyzed by quantum
chemical calculation,[5] and their interesting reactivity in par-
ticular in small molecule activation reactions studied.[6] In case
of group 15 compounds, double-bonded species of the general
type RE=ER have been kinetically stabilized by use of steri-
cally encumbered organic substituents (Scheme 1).[7] However,
the low number of structurally characterized compounds of the
type R2E2 (without transition metal complexes) containing
As=As (11), Sb=Sb (7) and Bi=Bi (12) double bonds[8] com-
pared to diphosphenes containing a P=P double bond
(Ͼ75)[9]] indicate the lower bond strength of the E=E double
bond of heavier group 15 elements, resulting from the
decreasing π-bond energy.[10] In addition, NHC-stabilized
(NHC=N-heterocyclic carbene) diatomic molecules of the type
(NHC)2E2 (E = P, As, Sb), which formally contain the group
15 elements in the oxidation state 0, were prepared,[11] but
these exhibit E–E single bonds.
Scheme 1. Structurally characterized distibenes R2Sb2 containing a
Sb=Sb double bond.
Distibenes have been kinetically-stabilized by use of steri-
cally demanding substituents (Scheme 1).[12] Their electronic
situation was investigated by quantum chemical calculation[13]
and their chemical reactivity was studied in detail,[14] i.e. their
coordination ability toward transition metals[15] and their reac-
tivity in single electron reduction reactions, that yielded the
corresponding radical anion,[16] respectively.
We recently observed that reactions of two equivalents of
monovalent gallanediyl LGa {L
=
HC[C(Me)N(2,6-
iPr2C6H3)]2} with EX3 (E = As, Sb, Bi; X = Cl, NR2) yielded
the corresponding Ga-substituted dipnictenes [L(X)GaE]2 with
a central E=E double bond, under mild reaction conditions.[17]
Upon heating, the distibenes [L(X)GaSb]2, were converted into
Sb analogues of bicyclo[1.1.0]butane [L(X)Ga]2(μ,η1:1-Sb4)
(X = Cl, NMe2, NMeEt).
To further prove the influence of the X substituent on the
reactivity of the starting antimonides SbX3, we systematically
investigated reaction of two equivalents of LGa with two anti-
* Prof. Dr. S. Schulz
Fax: + 49-201-1834635
E-Mail: stephan.schulz@uni-due.de
Homepage: http://www.uni-due.de/ak_schulz/
[a] Faculty of Chemistry and Center for Nanointegration Duisburg-
Essen (CENIDE)
University of Duisburg-Essen
45117 Essen, Germany
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201800204 or from the au-
thor.
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mony trihalides SbX3 (X = Br, I) and antimony triethoxide and after 5 d at –30 °C (3). 1 and 2 crystallize in the triclinic
¯
Sb(OEt)3, respectively. The resulting Ga-substituted distibenes space group P1 with the molecule placed on center of inver-
[L(X)GaSb]2 [X = Br (1), I (2), OEt (3)] (Scheme 2) were char- sion, whereas 3 crystallizes in the monoclinic space group
acterized by heteronuclear (1H, 13C) NMR spectroscopy and P21/c, respectively (Figure 1, Figure 2, and Figure 3).[19]
single-crystal X-ray diffraction and the structural parameters
within this class of compounds are compared. In addition,
quantum chemical calculations were performed to investigate
the electronic structure of 1–3.
Scheme 2. Synthesis of 1 to 3.
Results and Discussion
Reactions of two equivalents of LGa with SbX3 in toluene
at ambient temperature proceeded with elimination of LGaX2
(X = Br, I, OEt), as was proven by in situ 1H NMR spec-
troscopy, and formation of the Ga-substituted distibenes
[L(X)GaSb]2 [X = Br (1), I (2), OEt (3)], which were isolated
in high yields as green crystalline solids after recrystallization
from solutions in toluene at ambient temperature.
Figure 1. Solid state structure of 1. Non-hydrogen atoms shown as
thermal ellipsoids at 50% probability levels; hydrogen atoms are omit-
ted for clarity. Part depicted in pale colors is generated by symmetry.
1–3 are soluble in benzene and toluene and can be stored in
solution and as isolated crystals in an argon atmosphere at am-
bient temperature. The 1H NMR spectra of 1–3 in [D6]benzene
show two septets and four doublets for the magnetically in-
equivalent iPr groups of the β-diketiminate ligand and single
resonances for the γ-CH and the methyl groups of the C3N2M
ring, whereas the 13C NMR spectra of 1–3 each show 14 sig-
nals of the β-diketiminate groups (Table 1). Comparable find-
ings were reported for dipnictenes of the general type
[L(Cl)GaE]2 (E = As,[17c] Sb[17b]).
The UV/Vis spectra of solutions of 1–3 in toluene (Figure
S12, Supporting Information) each show a maximum absorp-
tion at 354 nm, which agrees very well with the value reported
by Power et al. for LGa (340 nm)[18] and thus can be assigned
to the L(X)Ga substituent, as well as a second absorption maxi-
mum at 437 (1) and 438 nm (2) due to the π–π* transitions.
Comparable values were previously reported for other
distibenes RSb=SbR.[7a] In contrast, no π–π* absorption was
observed for 3.
Figure 2. Solid state structure of 2. Non-hydrogen atoms shown as
thermal ellipsoids at 50% probability levels; hydrogen atoms are omit-
Single crystals of 1–3 were obtained upon storage of solu-
tions in toluene at ambient temperature after 2 h (1), 3 h (2), ted for clarity. Part depicted in pale colors is generated by symmetry.
1
a)
Table 1. H NMR chemical shifts of [L(X)GaSb]2
.
X =
γ-CH
CHMe2
CHMe2
CMe
Cl [17b]
Br (1)
I (2)
OEt (3)
NMe2 [17a]
NMeEt [17b]
4.97
5.00
5.06
4.82
4.75
4.78
3.91, 3.05
3.98, 3.05
4.04, 3.05
4.02, 2.99
3.62, 2.90
3.95, 3.82, 2.90
1.30, 1.20, 1.11, 1.01
1.40, 1.20, 1.12, 0.99
1.42, 1.21, 1.14, 0.97
1.51, 1.39, 1.29, 1.04
1.35, 1.29, 1.02, 1.00
1.32, 1.28, 1.03, 1.01
1.63
1.63
1.62
1.62
1.61
1.61
a) 300 MHz, 25 °C, [D6]benzene.
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tibenes [L(X)GaSb]2 [X
=
Cl 2.6461(2) Å, NMeEt
and distibenes
2.6433(6) Å,[17b] NMe2 2.6477(3) Å[17a]
]
RSb=SbR containing sterically demanding organic substitu-
ents, for which values from 2.64 to 2.70 Å were reported.[21]
The Sb=Sb double bonds are shorter than Sb–Sb single bonds
typically observed in distibines R4Sb2.[22] The Sb–Sb bond
length in the parent system, HSb=SbH, was calculated by dif-
ferent groups, yielding values between 2.608 Å and
2.682 Å,[23] respectively. The Ga–Sb bond lengths [1:
2.6129(11) Å, 2: 2.5919(5) Å, 3: 2.6012(5), 2.5987(5) Å] are
slightly shorter than the sum of the calculated single bond
covalent radii for Ga (1.24 Å) and Sb (1.40 Å) atoms,[24] but
comparable to Ga–Sb single bonds observed in other Ga-sub-
stituted distibenes [L(X)GaSb]2 [X = Cl 2.58178(19) Å,
NMeEt 2.6169(5) Å,[17b] NMe2 2.6200(4) Å[17a]], tetrastibines
[(LGaX)2(μ,η1:1-Sb4] [X
=
Cl 2.6008(13) Å,[17b] NMe2
Figure 3. Solid state structure of 3. Non-hydrogen atoms shown as
thermal ellipsoids at 50% probability levels; hydrogen atoms are omit-
ted for clarity.
2.5975(5) Å[17a]] as well as the stibanyl radical [L(Cl)Ga]2Sb·
[2.5899(4), 2.5909(3) Å].[25]
In contrast, Ga–Sb single bonds in [(LGa)2(μ,η2:2-Sb4)]
[2.6637(11) Å],[26] dmap-Ga(Et)2Sb(SiMe3)2 [dmap
=
The centrosymmetric (1, 2) Sb2 units are coordinated by two
LGaX groups [X = Br (1), I (2), OEt (3)] in a trans-bent orien-
tation as is typically observed for distibenes. The Ga atoms are
tetrahedrally coordinated and are slightly off the best plane of
the ligand’s backbone (1: 0.599(4) Å, 2: 0.583(3) Å, 3:
0.593(5) Å and 0.526(5) Å]. The Ga–X bond lengths [X = Cl
2.2319(4) Å,[17b] Br 2.4126(10) Å (1), I 2.6010(5) Å (2)] in-
crease with increasing atomic number of the halogen atom
(Table 2) and the Ga–N bond lengths [1.965(3), 1.959(3) Å (1),
1.940(2), 1.961(2) Å (2), 1.962(3), 1.969(3) Å (3)] are signifi-
cantly shorter than those in gallanediyl LGa [2.0528(14) Å,
2.0560(13) Å][18] as is typically observed upon oxidation of
the Ga atom in LGa.[20]
4-Me2NC5H4N, 4-dimethylaminopyridine; 2.648(1) Å][27] as
well as in four- and six-membered heterocycles [R2GaSbRЈ2]x(x
= 2, 3), which were found to range from 2.666 Å to 2.772 Å,[28]
are slightly elongated. Gallastibenes of the general type
LGaSbGa(X)L, which contain a Ga=Sb double bond, showed
significantly shorter Ga–Sb single bonds [F: 2.5596(3) Å, Cl:
2.5528(2) Å, Br: 2.5662(3) Å, I: 2.5478(6) Å] and Ga–Sb
double bonds [F: 2.4601(3) Å, Cl: 2.4629(2) Å, Br:
2.4502(3) Å, I: 2.4496(8) Å], respectively.[25,29]
The Ga–Sb–Sb bond angles in 1 [90.92(3)°], 2 [89.685(15)°]
and 3 [88.313(14)°, 92.238(15)°] agree almost perfectly with
those in [L(Cl)GaSb]2 [89.476(6)°],[17b] whereas those of the
amido-substituted derivatives [L(X)GaSb]2 [X = NMeEt
95.839(16)°,[17b] NMe2 94.710(8)°[17a]] are slightly enlarged,
most likely resulting from the higher steric demand of the
amido substituents. In addition, the calculated H–Sb–Sb bond
angle of HSb=SbH (93.0°)[23] falls in between these values.
The Ga–Sb–Sb bond angles in 1 to 3, which are very close to
90°, indicate a high p orbital character within the bonding elec-
tron pairs and, as a consequence, high s character of the elec-
tron lone pair of the Sb atoms. Distibenes ArSb=SbAr contain-
ing sterically encumbered organic substituents (terphenyl li-
gands) show significantly larger C–Sb–Sb bond angles be-
tween 94.1° and 105.4° (7 hits in the CCDC database),[12] re-
sulting from repulsive interactions between the bulky aryl li-
gands.
Table 2. Selected bond lengths /Å and angles /° of LGaX coordinated
distibenes [L(X)GaSb]2 [X = Br (1), I (2), OEt (3)].
1
2
3
Sb1–Ga1
Sb2–Ga2
Sb1–Sb1a/2
Ga1–X1
Ga2–X2
Ga1–N1
Ga1–N2
N1–C1
N2–C3
2.6129(11)
–
2.6442(11)
2.4126(10)
–
1.965(3)
1.959(3)
1.334(5)
1.335(5)
1.412(6)
1.396(6)
90.92(3)
–
2.5919(5)
–
2.6310(5)
2.6010(5)
–
1.940(2)
1.961(2)
1.335(3)
1.325(3)
1.386(4)
1.402(4)
89.69()
–
2.6012(5)
2.5987(5)
2.6495(4)
1.830(3)
1.824(3)
1.962(3)
1.969(3)
1.334(5)
1.332(5)
1.402(5)
1.397(5)
92.24(2)
88.31(2)
117.87(9)
110.26(10)
110.61(9)
121.30(9)
94.47(13)
122.8(3)
124.7(4)
127.7(4)
C1–C2
C2–C3
Ga1–Sb1–Sb1a
Ga2–Sb2–Sb1
Sb1–Ga1–X1
Sb2–Ga2–X2
N1–Ga1–Sb1
N2–Ga1–Sb1
N1–Ga1–N2
N1–C1–C2
N2–C3–C2
C1–C2–C3
The synthesis of 1–3 demonstrates the high synthetic poten-
tial for bond activation reactions of gallanediyl LGa and for
the stabilization of unusual bonding properties. It is note-
worthy, that reactions of the N-heterocyclic carbene 1,3-
116.79(3)
–
116.21()
–
121.14(8)
111.57(9)
96.55(13)
123.5(4)
122.5(3)
129.7(3)
111.88(7)
121.14(6)
96.64(9)
123.0(2)
124.2(3)
128.9(3)
bis(2,6-diisopropylphenyl)-imidazol-2-ylidene
(IPr)
with
group 15 trihalides EX3 (E = P, Sb, Bi; X = Cl, Br), which were
recently reported by Goichochea et al.,[30,31] did not result in
the formation of the corresponding dipnictenes. Instead, the
reactions of IPr with PX3 yielded [P2(IPr)2Br3]Br, exhibiting a
The central Sb–Sb bond lengths [1: 2.6442(11) Å, 2:
2.6310(5) Å, 3: 2.6495(4) Å] are almost identical and agree P–P single bond bridged by a bromine atom,[30] whereas the
very well with those of previously reported Ga-substituted dis- reactions with EBr3 (E = Sb, Bi) only gave the simple adducts
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IPr–EBr3,[31] whereas Sb–Sb or Bi–Bi bond formation was not
observed.
The charge distribution in the [Ga(X)Sb]2 unit is mainly in-
fluenced by the halide substituent (X). As was expected, the
To investigate the bonding situation of 1 to 3 and the elec- natural charge of the halide atoms increases with their elec-
tronic nature within the Ga–Sb–Sb–Ga unit in more detail, the tronegativity values (F: –0.76 e, Cl: –0.52 e, Br: –0.50 e, I:
structures of (L(X)GaSb]2 [X = Br (1), I (2), OEt (3)] were –0.40 e), resulting in a higher positive charge at the central
investigated by quantum chemical calculations at the gallium atom (F: 1.48 e, Cl: 1.18 e, Br: 1.14 e, I: 1.03 e). As
PBE0/def2-TZVP level of theory. The iPr-groups were substi- a result, the charge at the Sb atom becomes more negative (F:
tuted by sterically less demanding Me groups.
–0.15 e, Cl: –0.13 e, Br: –0.10 e, I: –0.10 e). This is also
The resulting structural parameters of the Ga–Sb–Sb–Ga reflected in the polarization of the Sb–Ga bond. The polariza-
unit coincide well with the experimentally values (Table 3). tion of the bond towards the central Sb atom increases in the
Sb–Sb bond lengths lay within 0.012 Å, Sb–Ga within order 59, 60, 62, and 63% from I to F, in conjunction with the
0.022 Å, Ga–X within 0.025 Å and Ga–N within 0.032 Å devi- increasing electronegativity of the halide. On the other hand,
ation from the experimental values of 1 to 3. The average devi- the electronic character of the Sb–Sb and Sb–Ga bonding or-
ation of the bond angles is greater for Sb–Ga–X (1: 3.69°, 2: bitals is not largely influenced by the halide substituent X. The
4.52°, 3: 3.39°) than for Ga–Sb–Sb (1: 1.72°, 2: 0.08°, 3: Sb σ bonds have almost 90% and the π bond 99% p character
1.68°), most likely resulting from the replacement of the iPr in all cases. The Sb lone-pairs also have a constant 76–78% s
groups by sterically less demanding Me groups.
character.
The bond polarization of the Sb–O bond and the orbital
Table 3. Selected experimental and calculated bond lengths /Å and
angles /° of [L(X)GaSb]2 [X = Br (1), I (2), OEt (3)].
characters in 3 fall between the values of the F and Cl substi-
tuted molecules, as was expected from the electronegativity
and steric demand of the OEt substituent. Only the charge of
the central oxygen atom is more negative (–0.96 e) than the
corresponding F (–0.76 e), since it can withdraw electron den-
sity not only from the Ga but also from the adjacent C atom.
1
2
3
Sb–Gaexp.
Sb–Gacalcd.
2.6129(11)
2.621
2.5919(5)
2.613
2.6012(5), 2.5987(5)
2.653
2.619
2.614
2.627
Sb–Sbexp.
Sb–Sbcalcd.
Ga–Xexp.
2.6442(11)
2.632
2.4126(10)
2.381
2.6310(5)
2.636
2.6010(5)
2.601
2.6495(4)
2.627
1.830(3), 1.824(3)
1.838
Ga–Xcalcd.
Conclusions
2.394
2.601
1.833
Ga–Sb–Sbexp.
Ga–Sb–Sbcalcd. 87.0
91.4
Sb–Ga–Xexp.
Sb–Ga–Xcalcd.
90.92(3)
89.69()
89.7
89.8
116.21()
111.7
111.7
92.24(2), 88.31(2)
89.3
94.6
117.87(9), 110.26(10)
118.0
116.9
Distibenes containing a Sb=Sb double bond can generally
be synthesized by reaction of two equivalents of LGa with
antimony trihalides SbX3 (X = Br, I) and triethoxide
Sb(OEt)3. The reactions proceed with insertion of two gallan-
diyls into two Sb–X bonds, followed by elimination of LGaX2
and LGa(OEt)2, respectively, and formation of [L(X)GaSb]2
[X = Br (1), I (2), OEt (3)]. Comparable reactions were pre-
viously observed between LM (M = Al, Ga) and EX3 and
E(NR2)3 (E = As, Sb, Bi; X = halide), hence this reaction path-
way offers a general route to metal-substituted dipnictogenes
of the general type [L(X)ME]2.[17] Quantum chemical calcula-
tions with these complexes are currently performed to prove if
the L(X)Ga substituents only serve as kinetically stabilizing
(sterically demanding) ligand or if dispersion interactions be-
tween the ligands, as was recently reported for main group
element compounds,[32] also lead to a stabilization of such
molecules.
116.79(3)
110.1
116.1
The HOMO in the halide-substituted distibenes, which is
located on the Ga–Sb–Sb–Ga motif, is dominated by contri-
butions from the Sb=Sb double bond (px and py orbitals of the
central Sb atoms). In addition, it shows a small contribution
from the Ga–X σ orbitals, as derived from Löwdin orbital pop-
ulations. The LUMO is centered on both Sb atoms in all cases
and is an almost exclusive representation of the Sb=Sb π* or-
bitals (Figure 4). The calculated HOMO-LUMO gap energies
of 1 (274 kJ·mol–1), 2 (281 kJ·mol–1) and 3 (279 kJ·mol–1)
correspond to light absorption of 425–437 nm, which explains
the observed yellow to green color of the compounds and
which agree to the π–π* absorption bands observed for 1 and
2.
Experimental Section
General Procedures: All manipulations were performed using
Schlenk-line and glove-box techniques in a purified argon atmosphere.
Toluene and hexane were obtained after passing these solvents through
activated alumina columns with an MBraun Solvent Purification Sys-
tem. Deuterated NMR solvents were dried with potassium, purified by
distillation, stored over activated molecular sieves (4 Å) and degassed
prior to use. Karl Fischer titration of the dry solvents show values
less than 3 ppm. LGa[18] was prepared according to literature methods,
whereas SbBr3 and SbI3 were obtained from commercial sources.
Sb(OEt)3 was prepared by literature method.[33] Table S1 (Supporting
Figure 4. Exemplary HOMO (left) and LUMO (right) of 1.
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Information) summarizes the 1H NMR values of the side-products
yielded pale yellow crystals, which were isolated by filtration. Twofold
LGaX2 (X = Cl, Br, I) in C6D6.
recrystallization from solutions in n-hexane (0.5 mL) at room tempera-
ture finally yielded pure 3. M. p. 216–217 °C. Yield 42 mg
(0.032 mmol, 54%). C62H92N4O2Ga2Sb2: calcd. C 56.92; H 7.09; N
4.28%; found: C 56.97; H 7.03; N 4.31%. 1H NMR (C6D6, 300 MHz,
25 °C): δ = 7.14–6.92 (m, 12 H, C6H3-2,6-iPr2), 4.83 (s, 2 H, γ-CH),
Instrumentation: 1H (300 and 500 MHz) and 13C{1H} (75.5 MHz)
NMR spectra (δ in ppm) were recorded with a Bruker Avance DPX-
300 spectrometer and the spectra were referenced to internal C6D5H
(1H: δ = 7.154; 13C: δ = 128.39 ppm) and C6D5CHD2 (1H: δ = 2.09;
13C: δ = 20.40 ppm). Microanalyses were performed at the Elemental
Analysis Laboratory of the University of Duisburg-Essen. IR spectra
were measured with an ALPHA-T FT-IR spectrometer equipped with
a single reflection ATR sampling module. UV/Vis spectra were re-
corded with a Varia Carry 300. The melting points were measured with
a Thermo Scientific 9300 apparatus.
3
3
4.03 [sept, JH,H = 6.9 Hz, 4 H, CH(CH3)2], 3.90 [quartet, JH,H
=
3
6.9 Hz, 4 H, OCH2CH3], 3.01 [sept, JH,H = 6.6 Hz, 4 H, CH(CH3)2],
3
1.63 (s, 12 H, ArNCCH3), 1.40 [d, 12 H, JH,H = 6.6 Hz, CH(CH3)2],
3
3
1.38 (triplet, JH,H = 6.6 Hz, 6 H, OCH2CH3), 1.30 [d, 12 H, JH,H
=
6.9 Hz, CH(CH3)2], 1.05 [d, 24 H, JH,H = 6.6 Hz, CH(CH3)2]. 13C
NMR (C6D6, 75 MHz, 25 °C): δ = 168.71 (ArNCCH3), 145.61,
142.88, 142.49, 127.10, 124.98, 124.23 (C6H3), 97.68 (γ-CH),
63.15 (OCH2CH3), 29.10 [CH(CH3)2], 27.76 [CH(CH3)2], 26.03
[CH(CH3)2], 25.20 [CH(CH3)2], 25.01 [CH(CH3)2], 24.70[CH(CH3)2],
24.30 (ArNCCH3), 21.30 (OCH2CH3). IR (neat): ν˜ = 2954, 2925,
2861, 2837, 1558, 1528, 1464, 1441, 1394, 1318, 1260, 1172, 1108,
1061, 1020, 938, 904, 857, 792, 757, 606, 530, 436 cm–1. UV/Vis
(toluene): λ (ε) = 354 nm (16760 m–1·cm–1).
3
General Procedure for the Synthesis of 1 and 2: LGa (100 mg,
0.205 mmol) and SbX3 (X = Br, 23.4 mg, 0.103 mmol; I 23.4 mg,
0.103 mmol) were dissolved in 2 mL of toluene in a Schlenk tube and
stirred at room temperature for 2 d. The solution was concentrated in
vacuo and 2 mL of hexane were added. Yellowish-green crystals of 1
and 2, which were formed upon storage at ambient temperature, were
isolated by filtration and recrystallized from toluene solution to afford
pure form of 1 and 2.
Single Crystal X-ray Diffraction: Crystallographic data of 1 to 3,
which were collected with a Bruker AXS D8 Kappa diffractometer
with APEX2 detector (Mo-Kα radiation, λ = 0.71073 Å) at 296(2) K
(1) and 100(2) K (2, 3), are summarized in Table S1 (Supporting Infor-
mation). The solid-state structures of 1 to 3 are shown in Figure 1,
Figure 2, and Figure 3, bond lengths and angles of 1 to 3 are summa-
rized in Table 2. The structures were solved by Direct Methods
(SHELXS-97) and refined anisotropically by full-matrix least-squares
on F2 (SHELXL-2016).[34,35] Absorption corrections were performed
semi-empirically from equivalent reflections on basis of multi-scans
(Bruker AXS APEX2). Hydrogen atoms were refined using a riding
model or rigid methyl groups. The crystals of 1 cracked and lost crys-
tallinity upon cooling. Consequently, the measurement was done at
room temperature. Unfortunately, the grease used to mount the crystal
was not viscous enough and the crystal slipped during the measure-
ment. As a result, only part of the obtained frames could be success-
fully integrated, and the completeness of the data set is low.
[L(Br)GaSb]2 (1): Yield: 44 mg (65%). Mp.: 239 °C (dec.).
C58H82N4Br2Ga2Sb2 (M = 1378.15 g·mol–1): calcd. C 50.55 H 6.00 N
4.07%; found: C 49.95 H 6.07 N 4.24%; found: C 49.5 H 6.22 N
1
3.16%. H NMR (C6D6, 300 MHz, 25 °C): δ = 7.12–6.92 (m, 12 H,
3
C6H3–2,6-iPr2), 5.00 (s, 2 H, γ-CH), 3.98 [sept, JH,H = 6.7 Hz, 4 H,
3
CH(CH3)2], 3.05 [sept, JH,H = 6.8 Hz, 4 H, CH(CH3)2], 1.63 (s, 12
3
H, ArNCCH3), 1.40 [d, 12 H, JH,H = 6.7 Hz, CH(CH3)2], 1.20 [d, 12
3
3
H, JH,H = 6.7 Hz, CH(CH3)2], 1.12 [d, 12 H, JH,H = 6.7 Hz,
3
CH(CH3)2], 0.99 [d, 12 H, JH,H = 6.7 Hz, CH(CH3)2]. 13C NMR
(C6D6, 75 MHz, 25 °C): δ = 169.3 (ArNCCH3), 146.3 (C6H3), 142.7
(C6H3), 141.2 (C6H3), 125.6 (C6H3), 124.2 (C6H3), 98.4 (γ-CH), 29.74
[CH(CH3)2], 28.2 [CH(CH3)2], 28.2 [CH(CH3)2], 25.9 [CH(CH3)2],
24.9 [CH(CH3)2], 24.5 [CH(CH3)2], 24.1 (ArNCCH3). IR: ν˜ = 3060,
3018, 2962, 2923, 2864, 1150, 1518, 1460, 1437, 1385, 1360, 1316,
1289, 1258, 1173, 1100, 1018, 935, 862, 794, 771, 756, 712, 635, 523,
441 cm–1. UV/Vis (toluene):
(5377 m–1·cm–1).
λ (ε) = 355 (41280), 437 nm
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK.
Copies of the data can be obtained free of charge on quoting
the depository numbers CCDC-1827131 (1), CCDC-1827132 (2),
and CCDC-1837837 (3) (Fax: +44-1223-336-033; E-Mail:
deposit@ccdc.cam.ac.uk, http://www.ccdc.cam.ac.uk).
[L(I)GaSb]2 (2): Yield: 49 mg (67%). Mp.: 173 °C (dec.).
C58H82N4I2Ga2Sb2 (M = 1472.12 g·mol–1): calcd. C 47.13 H 6.00 N
3.79%; found: C 47.02 H 5.87 N 3.59%; found: C 48.0 H 5.92 N
1
3.59%. H NMR (C6D6, 300 MHz, 25 °C): δ = 7.12–6.99 (m, 12 H,
3
C6H3–2,6-iPr2), 5.06 (s, 2 H, γ-CH), 4.04 [sept, JH,H = 6.7 Hz, 4 H,
3
CH(CH3)2], 3.05 [sept, JH,H = 6.7 Hz, 4 H, CH(CH3)2], 1.62 (s, 12
Supporting Information (see footnote on the first page of this article):
A CIF file giving X-ray crystallographic data of 1 and 2, 1H NMR
spectra of LGaX2 (X = Cl, Br, I) as well as spectroscopic details (1H,
13C NMR. IR, UV/Vis) and crystallographic details of 1–3.
3
H, ArNCCH3), 1.42 [d, 12 H, JH,H = 6.7 Hz, CH(CH3)2], 1.21 [d, 12
3
3
H, JH,H = 6.7 Hz, CH(CH3)2], 1.14 [d, 12 H, JH,H = 6.7 Hz,
3
CH(CH3)2], 0.97 [d, 12 H, JH,H = 6.7 Hz, CH(CH3)2]. 13C NMR
(C6D6, 75 MHz, 25 °C): δ = 169.4 (ArNCCH3), 146.4 (C6H3), 142.9
(C6H3), 141.2(C6H3), 125.8 (C6H3), 124.3 (C6H3), 98.8 (γ-CH), 29.7
[CH(CH3)2], 29.6 [CH(CH3)2], 28.4 [CH(CH3)2], 25.0 [CH(CH3)2],
24.6 [CH(CH3)2], 24.6 [CH(CH3)2], 24.2 (ArNCCH3). IR: ν˜ = 3060,
3018, 2962, 2922, 2864, 1551, 1519, 1460, 1437, 1385, 1360, 1312,
1286, 1234, 1174, 1098, 1057, 1018, 981, 936, 862, 794, 770, 756,
710, 635, 524, 500, 438 cm–1. UV/Vis (toluene): λ (ε) = 354 (31949),
436 nm (2656 m–1·cm–1).
Acknowledgements
Stephan Schulz gratefully acknowledges financial support by the Ger-
man Research Foundation DFG (project SCHU1069/22–1) and the
University of Duisburg-Essen. Financial support by the International
Max Planck Research School IMPRS RECHARGE (L.J.) is gratefully
acknowledged.
[L(EtO)GaSb]2 (3): RGa (0.116 g, 0.239 mmol) and Sb(OEt)3
(0.031 g, 20 μL, 0.119 mmol) were dissolved in 0.5 mL of n-hexane
and stirred at ambient temperature for 2 h to yield a yellow-brown
solution, which was heated at 70 °C for 1 h to ensure the reaction
completion. Cooling to ambient temperature and storage for 2 h
Keywords: Gallium; Antimony; Multiple bonds; X-ray dif-
fraction
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5
© 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Journal of Inorganic and General Chemistry
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
15782 reflections (θmax = 30.561°), 8306 unique (Rint = 0.0521);
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synthesis 1.064 e·Å–3/ –1.117 e·Å–3; max./min. transmission 0.75/
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data for 2: [C58H82Ga2I2N4Sb2], M = 1472.01, yellowish-green
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[19] Crystal data for 1: [C58H82Br2Ga2N4Sb2], M = 1378.03, yellow-
ish-green crystal, (0.183ϫ0.171ϫ0.149 mm); triclinic, space
¯
group P1; a = 10.487(4) Å, b = 12.427(4) Å, c = 13.362(5) Å; α
= 94.057(18)°, β = 106.627(18)°, γ = 107.006(17)°, V = Received: May 15, 2018
1572.9(10) Å3; Z = 1; μ = 3.003 mm–1; ρcalc = 1.455 g·cm–3;
Published online: ᭿
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Journal of Inorganic and General Chemistry
ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
J. Krüger, J. Schoening, C. Ganesamoorthy, L. John,
C. Wölper, S. Schulz* ........................................................ 1–8
Synthesis and X-ray Crystal Structures of Ga-substituted Dis-
tibenes [L(X)GaSb]2
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