Organo-tricyanoborates as tectons: Illustrative coordination polymers based on copper(I) derivatives

Article abstract of DOI:10.1021/ic0506153

The first systematic study on the use of tricyanoborates as ligands is presented. The tricyanoborates [RB(CN)₃]^- (R = oct and Ph) can be prepared by direct cyanation of RBCl₂ precursors as well as by thermolysis of the corresponding isocyanides [RB(NC)₃] ^-. The first organo-cyanogallates [RGa(CN)₃]^- (R = Bu, C₆H₂-2,4,6-Me₃) were prepared from the corresponding dichloride, the structure of Et₄N[mesGa(CN) ₃] being confirmed crystallographically. The reaction of equimolar [RB(CN)₃]^- (R = oct, Ph) and [Cu(MeCN)₄] ⁺ afforded two-dimensional polymers [RB-(CN)₃Cu(NCMe)]. The sheets arise via conjoined hexagonal B₃Cu₃(CN) ₆ rings with chair conformations. The reaction of excess [PhB(CN)₃]^- and [Cu(MeCN)₄]⁺ gives the polymer [K(18-crown-6)]{Cu[PhB(CN)₃]₂}. Treatment of [PhB(CN)₃]^- with [Cu(PCy₃)₂(NCMe) _x]PF₆ gave the one-dimensional polymer [PhB(CN) ₃Cu(PCy₃)₂], wherein two of the three BCN substituents are coordinated.

Full text of DOI:10.1021/ic0506153

Inorg. Chem. 2005, 44, 6256−6264
Organo-Tricyanoborates as Tectons: Illustrative Coordination Polymers
Based on Copper(I) Derivatives
Haijun Yao, Matthew L. Kuhlman, Thomas B. Rauchfuss,* and Scott R. Wilson
Department of Chemistry, UniVersity of Illinois at Urbana-Champaign, Urbana, Illinois 61801
Received April 21, 2005
The first systematic study on the use of tricyanoborates as ligands is presented. The tricyanoborates [RB(CN)3]-
(R oct and Ph) can be prepared by direct cyanation of RBCl2 precursors as well as by thermolysis of the
corresponding isocyanides [RB(NC)3]-. The first organo-cyanogallates [RGa(CN)3]- (R
Bu, C6H2-2,4,6-Me3) were
prepared from the corresponding dichloride, the structure of Et4N[mesGa(CN)3] being confirmed crystallographically.
The reaction of equimolar [RB(CN)3]- (R oct, Ph) and [Cu(MeCN)4]+ afforded two-dimensional polymers [RB-
(CN)3Cu(NCMe)]. The sheets arise via conjoined hexagonal B3Cu3(CN)6 rings with chair conformations. The reaction
)
)
)
of excess [PhB(CN)3]- and [Cu(MeCN)4]+ gives the polymer [K(18-crown-6)]
{Cu[PhB(CN)3]2}. Treatment of
[PhB(CN)3]- with [Cu(PCy3)2(NCMe)x]PF6 gave the one-dimensional polymer [PhB(CN)3Cu(PCy3)2], wherein two of
the three BCN substituents are coordinated.
Introduction
Of perennial interest for the design of molecular cages
are modular precursorsstectons or building blockssthat have
geometrically well-defined linking tendencies.1 Systematic
modification of these subunits promises to enable the
synthesis of molecules with tailored host-guest behavior.
Within the context of host-guest behavior, cyanometalates
have been heavily studied.2,3 For example, the Hoffmann salts
Ni(NH3)2Ni(CN)4, derived from [Ni(CN)4]2-, are amine-
pillared two-dimensional sheets, which selectively bind
aromatic guests (Figure 1A).4 Similarly, various Prussian
Blue analogues, which commonly have defects and vacan-
cies, have been employed for K+/Cs+ and CH4/CO2 separa-
tions.2,5 Less studied but relevant to this work are the layered
cyanocuprates [Cu2(CN)3]-.6 Mixed-ligand cyanometalates
generate interesting coordination polymers, some of which
* Corresponding author. E-mail: rauchfuz@uiuc.edu.
(1) Wang, X.; Simard, M.; Wuest, J. D. J. Am. Chem. Soc. 1994, 116,
12119-20. Su, D.; Wang, X.; Simard, M.; Wuest, J. D. Supramol.
Chem. 1995, 6, 171-78.
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Batten, S. R.; Murray, K. S. Aust. J. Chem. 2001, 54, 605-609.
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1974, 30A, 1989-2004. Uemasu, I.; Iwamoto, T. Chem. Lett. 1982,
973-6. Minceva-Sukarova, B.; Andreeva, L.; Ivanovski, G. J. Mol.
Struct. 1990, 219, 111-16.
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Figure 1. Schematic views of the Hoffmann-benzene clathrate [Ni(NH3)2-
Ni(CN)4] (top) and of PPh4[Cu2(CN)3] (bottom). The vertexes represent
metal atoms (Ni2+, Cu+), and the lines represent µ-CN groups.
6256 Inorganic Chemistry, Vol. 44, No. 18, 2005
10.1021/ic0506153 CCC: $30.25
© 2005 American Chemical Society
Published on Web 08/11/2005

Organo-Tricyanoborates as Tectons
also exhibit host-guest behavior.7 Mixed-ligand cyanometa-
lates also form discrete cages,8,9 which can exhibit highly
selective host-guest behavior reminiscent of the parent solid-
state materials.10,11
Scheme 1
Previous work on molecular tricyanometalates has em-
phasized cuboidal cages.9,10,12 These box-like structures are
a natural consequence of the ∼90° NC-M-CN angles of
the tricyanometalate precursors. In an effort to develop new
structural families of cyanometalate cages, we sought tricy-
ano building blocks with NC-M-CN angles > 90°. Such
building blocks could, for example, stabilize adamantanoid
cages. Our attention was drawn to the recently reported
coordination solid {Ag[FB(CN)3]}, formed from the reaction
of AgNO3, NaF, and K[B(CN)4].13 We decided to examine
the coordination chemistry of a range of [RB(CN)3]-
precursors, which we envisioned could be synthesized with
diverse substituents (H, alkyl, aryl) for use as building blocks.
The promise of this approach is illustrated by our recent
synthesis of the hexagonal prism {[PhB(CN)3]6[RhCp*]6}6+.14
Although salts of [B(CN)4]- have been well-studied,15-18
fewer of the tricyanoborates are known; these include Na-
[HB(CN)3],18 M[BF(CN)3] (M ) Li, K),17 and Me3SiNCBF-
(CN)3.17 Only limited coordination chemistry has been
reported for the tricyanides.
begins with the reaction of HBBr2 and AgCN.18,19 Conversion
of the resulting coordination polymer Ag[HB(NC)3]18 into
the more soluble Na+ salt via reduction with metallic Na
proved difficult to reproduce. We found, however, that
sodium sulfide smoothly and quantitatively converted Ag[H-
B(NC)3] into the desired Na[HB(NC)3]. This sodium salt was
transformed into the air-stable salt PPN[HB(NC)3] (PPN )
[N(PPh3)2]+), which, in refluxing Bu2O, rearranged into PPN-
[HB(CN)3] (Scheme 1).
The previously rare20 organocyanoborates can be prepared
by the AgCN route via the organo-triisocyanoborate, Et4N-
[PhB(NC)3], which was fully characterized. Direct cyanation
with KCN is easier, however. Thus, [K(18-crown-6)][PhB-
(CN)3] was synthesized via the reaction of PhBCl2 and 3
equiv of KCN in the presence of the crown ether in a THF
solution. This air-stable colorless salt was purified chro-
matographically and characterized by electrospray ionization
mass spectrometry (ESI-MS) as well as by 1H and 11B NMR
spectroscopy. The octyl analogue, [K(18-crown-6)][octB-
(CN)3], was prepared and characterized similarly.
Results and Discussion
Synthesis of [RB(CN)3]- and [RB(NC)3]-. The basic
chemistry of [HB(CN)3]- has been developed by Gyo¨ri et
al., who synthesized this anion via a multistep process that
Characterization of Et4N[PhB(CN)3] and Et4N[PhB-
(NC)3]. To further distinguish the isomeric boron tricyanides
and triisocyanides, we examined the Et4N+ salts of the Ph
derivatives of both. Regarding the IR spectra, νCN for Et4N-
[PhB(CN)3] is weak but occurs at a higher frequency than
Et4N[PhB(NC)3] (Figure 2), consistent with the literature,18,19
and as also seen for PPN[HB(CN)3] and PPN[HB(NC)3]. The
13C NMR spectrum of Et4N[PhB(CN)3] showed a 11B-
coupled quartet (J ) 66 Hz) at δ 130 assigned to BCN. For
comparison, J(B,C) coupling in [BFn(CN)4-n]- ranges from
71 to 90 Hz,17 but no such coupling was observed for Et4N-
[PhB(NC)3]. These two compounds are further distinguished
by their 11B NMR spectra, the cyanide and isocyanide
displaying singlets at δ -28.6 and -13.4, respectively.
Synthesis of [RGa(CN)3]- (R ) Bu, C6H2-2,4,6-Me3).
Both Ga(CN)3 and salts of [Ga(CN)4]- are known,21 but
otherwise, no work has been reported on the organic
derivatives. We attempted to prepare [BuGa(CN)3]- using
[K(18-crown-6)]CN and BuGaCl2. ESI-MS analysis showed,
(7) Beauvais, L. G.; Shores, M. P.; Long, J. R. J. Am. Chem. Soc. 2000,
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Int. Ed. 1998, 37, 1694-96. Contakes, S. M.; Rauchfuss, T. B. Angew.
Chem., Int. Ed. 2000, 39, 1984-86. Contakes, S. M.; Klausmeyer, K.
K.; Milberg, R. M.; Wilson, S. R.; Rauchfuss, T. B. Organometallics
1998, 17, 3633-35. Heinrich, J. L.; Berseth, P. A.; Long, J. R. Chem.
Commun. 1998, 1231-32. Sokol, J. J.; Shores, M. P.; Long, J. R.
Inorg. Chem. 2002, 41, 3052-54. Sokol, J. J.; Shores, M. P.; Long,
J. R. Angew. Chem., Int. Ed. 2001, 40, 236-39.
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Rauchfuss, T. B. Proc. Nat. Acad. Sci. U.S.A. 2002, 99, 4889-93.
(10) Kuhlman, M. L.; Rauchfuss, T. B. J. Am. Chem. Soc. 2003, 125,
10084-92.
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Chem., Int. Ed. 2003, 42, 2663-66.
(12) Hsu, J. K.; Bonangelino, C. J.; Kaiwar, S. P.; Boggs, C. M.; Fettinger,
J. C.; Pilato, R. S. Inorg. Chem. 1996, 35, 4743-51.
(19) Gyo¨ri, B.; Berente, Z. Inorg. Chem. 2001, 40, 1770-78. Gyo¨ri, B.;
Berente, Z.; Kiraly, R.; La´za´r, I. J. Chem. Soc., Perkin Trans. 1 2002,
300-01. Gyo¨ri, B.; Berente, Z.; Kova´cs, Z. Inorg. Chem. 1998, 37,
5131-41. Gyo¨ri, B.; Berente, Z.; La´za´r, I. Polyhedron 1998, 17,
3175-80. Emri, J.; Gyo¨ri, B. J. Chem. Soc., Chem. Commun. 1983,
1303-4. Emri, J.; Gyo¨ri, B. Polyhedron 1983, 2, 1273-9. Emri, J.;
Gyo¨ri, B. Polyhedron 1994, 13, 2353-7. Emri, J.; Kova´cs, Z.; Gyo¨ri,
B. Inorg. Chim. Acta 1995, 233, 119-25.
(20) Hunter, R.; Haueisen, R. H.; Irving, A. Angew. Chem., Int. Ed. Engl.
1994, 33, 566-8. Vei, I. C.; Pascu, S. I.; Green, M. L. H.; Green, J.
C.; Schilling, R. E.; Anderson, G. D. W.; Rees, L. H. Dalton Trans.
2003, 2550-57.
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Chem. Soc. 1997, 119, 6292-96.
(13) Hamilton, B. H.; Ziegler, C. J. Chem. Commun. 2002, 842-43.
(14) Kuhlman, M. L.; Yao, H.; Rauchfuss, T. B. Chem. Commun. 2004,
1370-71.
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629, 1229-34. Berkei, M.; Bernhardt, E.; Schu¨rmann, M.; Mehring,
M.; Willner, H. Z. Anorg. Allg. Chem. 2002, 628, 1734-40.
(16) Ku¨ppers, T.; Bernhardt, E.; Willner, H.; Rohm, H. W.; Ko¨ckerling,
M. Inorg. Chem. 2005, 44, 1015-22.
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Chem. 2003, 629, 677-85.
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28.
Inorganic Chemistry, Vol. 44, No. 18, 2005 6257

Yao et al.
Figure 2. IR spectra of [Et4N][PhB(NC)3] (top, red) and [Et4N][PhB-
(CN)3] (bottom, black) (0.1M sample of MeCN solution).
Figure 4. IR spectra of [K(18-crown-6)][PhB(CN)3] (A), [PhB(CN)3Cu-
(PCy3)2] (B), and [PhB(CN)3Cu(NCMe)] (C), all in KBr.
Reaction of [RB(CN)3]- (R ) H, octyl, Ph) and [Cu-
(NCMe)4]+. Reaction of PPN[HB(CN)3] with [Cu(NCMe)4]-
PF6 in MeCN solution gave an insoluble precipitate from
which single crystals could not be obtained. For this reason,
we focused on the organoborate derivatives.23
Figure 3. Molecular structure of the anion in Et4N[mesGa(CN)3]. Thermal
ellipsoids are drawn at the 35% level (N ) blue, C ) gray, and Ga )
green). Selected distances and angles: C4-Ga1-C1, 111.24(8); C4-Ga1-
C2, 118.82(8); C2-Ga1-C1, 101.47(9); C4-Ga1-C3, 116.22(9); C2-
Ga1-C3, 101.30(9); C1-Ga1-C3, 106.03(9); N1-C1-Ga1, 176.0(2);
N2-C2-Ga1, 177.5(2); N3-C3-Ga1, 178.1(2). Ga-C1, 1.997(2); Ga1-
C2, 1.996(2); Ga1-C3, 2.019(2); Ga1-C4, 1.971(2); C1-N1, 1.139(3);
C2-N2, 1.130(3); C3-N3, 1.074(3).
Treatment of a MeCN solution of [Cu(NCMe)4]PF6 with
1 equiv of [K(18-crown-6)][PhB(CN)3] gave a white solid,
which indeed proved slightly soluble in MeCN. The IR
spectrum of this solid features a single νCN band at 2173
cm-1, which is shifted to higher energy by 38 cm-1 versus
[K(18-crown-6)][PhB(CN)3], consistent with the coordination
of cyanide ligands (Figure 4). Note that in such species, the
however, that even after 10 days in a refluxing THF solution,
the mixture consisted mainly of the chlorides [BuGaCl3]-,
[BuGa(CN)Cl2]-, and [BuGa(CN)3Cl]-, together with
[BuGa(CN)3]-. The butyl and mesityl (mes) derivatives could
be more readily prepared using Et4NCN in a THF solution.
The pure cyanogallates are relatively air-stable, although the
purification of these salts required an anaerobic technique.
Solutions of Et4N[BuGa(CN)3] in MeCN are sensitive to
H2O.
The organo-tricyanogallium salts displayed the expected
IR, ESI-MS, and 1H and 13C NMR spectroscopic signatures.
Crystallographic characterization of Et4N[mesGa(CN)3] con-
firmed that the gallium is tetrahedral (Figure 3) with an
average Ga-CN distance of 2.003(2) Å, which is shorter
than that in [Cs(PhMe)2{CN(GaMe3)2}] [2.086(6) Å].22
ν
CN band for MeCN is usually weak and often not observed.
Single crystals, obtained by cooling a hot MeCN extract,
were characterized by X-ray diffraction. The solid has the
formula [PhB(CN)3Cu(NCMe)]‚0.5MeCN and adopts a two-
dimensional sheetlike structure. The sheets are formed by
conjoining B3Cu3(CN)6 hexagons, where the cyanides form
the edges and the copper and boron are alternating vertexes
(Figure 5). The hexagons adopt a shallow chair conformation,
reflecting the tetrahedral nature of the boron and copper sites,
the latter also bearing a MeCN ligand. A comparable chair
conformation is adopted also by the Rh3B3(CN)3 rings in
(23) General comments on metrical data: bond angles and distances are
supplied in the Supporting Information but reveal normal N-Cu
(1.96-2.07 Å), B-C (1.56-1.60 Å), and Cu-P (2.30 Å) distances.
Correspondingly, the N-Cu-N and C-B-C angles reflect the
tetrahedral geometry (99-118°) for the boron and copper(I) centers.
(22) Kopp, M. R.; Neumueller, B. Z. Anorg. Allg. Chem. 1998, 624, 1642-
46. Uhl, W.; Hannemann, F.; Saak, W.; Wartchow, R. Eur. J. Inorg.
Chem. 1999, 771-76.
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Organo-Tricyanoborates as Tectons
Figure 6. Space-filling model for [PhB(CN)3Cu(NCMe)]‚0.5MeCN. The
MeCN solvate molecules are omitted from half of the channels for clarity.
Hydrogen atoms are not shown.
Figure 5. Top: Fragment of the two-dimensional sheet of [PhB(CN)3Cu-
(NCMe)] (MeCN of solvation not shown). Bottom: the extended structure
of [PhB(CN)3Cu(NCMe)]. MeCN molecules of solvation are included in
the top layer but are omitted from the bottom sheet for clarity. N ) blue,
C ) gray, Cu ) light blue, and B ) orange.
the molecular prism {[PhB(CN)3]6[RhCp*]6}6+.14 Examina-
tion of the extended unit cell reveals that the Cu3B3(CN)6
hexagons are eclipsed with respect to the other sheets,
resulting in hexagonal channels. These channels are occupied
with noncoordinated molecules of MeCN (Figure 6). The
structure is polar in the sense that the phenyl groups project
from the same relative side of the sheets along the a axis.
Heating a slurry of [PhB(CN)3Cu(NCMe)] in refluxing PhCN
produced [PhB(CN)3Cu(NCPh)], characterized by the ap-
pearance of a new νCN band at 2234 cm-1. A single νBCN
band at 2173 cm-1 was observed for [PhB(CN)3Cu(NCPh)],
as in [PhB(CN)3Cu(NCMe)].
Figure 7. Extended structure of Cu[PhB(CN)3]2[K(18-crown-6)]‚MeCN
showing the B4Cu4(CN)8 pseudo-octagons. MeCN solvate, 18-crown-6, and
phenyl rings are omitted for clarity; N ) blue, C ) gray, B ) orange, Cu
) light blue, and K ) light blue.
is bound to K+, which is 8-coordinated, which explains the
observation of a single νCN band (2164 cm-1) in the IR
spectrum of [PhB(CN)3Cu(NCMe)]. The remaining B(CN)2
units link tetrahedral Cu centers to give a three-dimensional
network formed by conjoined B4Cu4(CN)8 pseudo-octagons
(Figure 7).
To investigate the effect of the organic substituents on the
coordination properties of the organo-tricyanoborates, we
examined the interaction of [K(18-crown-6)][octB(CN)3] and
[Cu(NCMe)4]PF6. Predictably, this condensation produced
a poorly soluble solid analyzing as [octB(CN)3Cu(NCMe)]-
The product of the reaction of [Cu(NCMe)4]PF6 and
[K(18-crown-6)][PhB(CN)3] proved sensitive to stoichiom-
etry. When the Cu/B ratio > 1, only the aforementioned
[PhB(CN)3Cu(NCMe)] precipitated from the solution; how-
ever, at Cu/B ) 0.5, we obtained a colorless homogeneous
solution. The 1H NMR spectrum showed the presence of one
crown ether for two Ph groups, consistent with the crystal-
lographically established formula {[K(18-crown-6)][PhB-
(CN)3]2Cu}‚MeCN. One of the three CN units on each boron
Inorganic Chemistry, Vol. 44, No. 18, 2005 6259

Yao et al.
Figure 8. Two views of the structure of [octB(CN)3Cu(NCMe)] highlighting the interdigitation of the octyl substituents. Thermal ellipsoids are drawn at
the 50% level (N ) blue, C ) gray, Cu ) light blue, and B ) orange).
‚MeCN. Single crystals of this solid could be obtained by
slowly cooling hot MeCN extracts. X-ray crystallographic
analysis again revealed a sheetlike hexagonal sheet with a
tiling pattern closely resembling that for [PhB(CN)3Cu-
(NCMe)] (Figure 8). In contrast to the phenyl derivative,
the octyl structure is nonpolar. The octyl substituents from
adjacent sheets interdigitate. The packing of these octyl
chains seals off the channels that are more accessible in the
related [PhB(CN)3]- derivative. On the opposite sides of
these hexagonal sheets, the Cu-NCMe groups similarly
interdigitate, although less deeply, with those on the adjacent
CuB(CN)3 sheet. Noncoordinated molecules of MeCN oc-
cupy sites between the nitrile ligands.
Attempts to prepare Cu+ derivatives of [RGa(CN)3]- were
disappointing. Following the protocols described above,
colorless precipitates were obtained from a MeCN solution,
but the IR spectra of these solids exhibited several bands in
the νCN region, suggesting that the Ga-CN bonds are not
robust.
Interaction of [PhB(CN)3]- and [Cu(PCy3)2(NCMe)x]+.
Treatment of MeCN solutions of [K(18-crown-6)][PhB-
(CN)3] with 1.33 equiv of [Cu(PCy3)2(NCMe)x]PF6 gave a
colorless precipitate. The IR spectrum of this solid revealed
νCN bands at 2173 and 2129 cm-1, the latter of which is
comparable to the νCN for [K(18-crown-6)][PhB(CN)3] (2135
cm-1, see Figure 4), indicative of noncoordination. The IR
spectrum in this region was unchanged for the solid and THF
solution. The 1H NMR spectrum of this THF-soluble species
features one set of phenyl signals and two distinct sets of
cyclohexyl signals. The 31P NMR spectrum also reveals two
signals indicating inequivalent phosphine ligands.
Single-crystal X-ray analysis of [PhB(CN)3Cu(PCy3)2]
revealed a one-dimensional polymer (Figure 9). The proposed
polymer model includes disordered positions for one phenyl
and two cyclohexyl groups. Two cyanide substituents of
[PhB(CN)3]- are coordinated, the third being free, giving a
linear polymer with a syndiotactic configuration. The Cu-N
and B-C distances are typical bond lengths for Cu-N and
6260 Inorganic Chemistry, Vol. 44, No. 18, 2005

Organo-Tricyanoborates as Tectons
Figure 9. One-dimensional chain of [PhB(CN)3Cu(PCy3)2]. Thermal
ellipsoids are drawn at the 50% level. Cyclohexyl substituents are omitted
for clarity; N ) blue, C ) gray, Cu ) light blue, P ) red, and B ) orange.
B-C with distances of 2.05-2.07 and 1.59-1.62 Å,
respectively.24 Darensbourg et al. have described molecular
rings based on cyanide coordination to Cu(I) phosphine
centers.25
Interaction of [RB(NC)3]- (R ) H, Ph) and [Cu-
(NCMe)4]+. Reaction of MeCN solutions of [Cu(NCMe)4]-
PF6 with the isocyanide Et4N[PhB(NC)3] resulted in the
formation of a white solid. The reaction of [Cu(NCMe)4]-
PF6 with PPN[HB(NC)3] gave similar results. The IR
spectrum of this product features a νCN band at 2158 cm-1,
which is shifted higher in energy relative to the anionic
isonitrile (2128 cm-1). Diffraction quality crystals could not
be obtained. Refluxing the solid in Bu2O for 10 h did not
effect conversion of this Cu-triisocyanoborate into [PhB-
(CN)3Cu(NCMe)], as judged by IR spectroscopy. Thus,
coordination inhibits the rearrangement of the BNC unit.
Summary
Organo-tricyanoborates represent a promising family of
ligands for the directed synthesis of coordination cages and
solids. Unlike the tris(pyrazolyl)borates,26 the tricyanoborates
are incapable of chelation but instead promote the formation
of polynuclear derivatives. These molecular tectons are
readily prepared from RBCl2, of which many examples are
known or can be made by hydroboration.27 Isomeric with
the tricyanides are the triisocyanoborates, which have a
fascinating chemistry in their own right,18,19 but thus far, a
limited coordination chemistry.28 The second route to cy-
anoborates entails direct cyanation of RBCl2 precursors. This
methodology can be applied to the preparation of related
gallium species, although in our hands, this species did not
form well-defined complexes.29
Figure 10. Schematic representation of the intersheet interactions in [RB-
(CN)3Cu(NCMe)] for R ) F (A), Ph (B), and oct (C).
The small but significant solubility of these coordination
polymers is attributed to the ability of MeCN to compete
with the Cu‚‚‚NCBR3 interactions. Three related but differing
structural motifs are exhibited for the Cu+ derivatives of
[RB(CN)3]-, for R ) F, Ph, and octyl. In all three cases,
sheetlike structures arise through edge-sharing of hexagonal
B3Cu3(CN)6 rings. Hexameric cyanometalates are prece-
dented in [Cu(CN)(PPh3)2]6.6 In the [PhB(CN)3]- and
[octB(CN)3]- derivatives, these hexagonal rings adopt chair
conformations and, further, are eclipsed relative to the
adjacent sheets. The previously reported [FB(CN)3Cu-
(NCMe)]13 is also best described as being two-dimensional
(Figure 10). In contrast to the organoborates, the B3Cu3(CN)6
rings in the fluoroborate adopt the boat conformation, and
The present work illustrates the use of the organoboron
tricyanides as precursors to coordination polymers. The new
polymers are two-dimensional, in contrast to CuB(CN)4.16
(24) Segal, B. G.; Lippard, S. J. Inorg. Chem. 1974, 13, 822-8. Melmed,
K. M.; Li, T.-I.; Mayerle, J. J.; Lippard, S. J. J. Am. Chem. Soc. 1974,
96, 69-75.
(25) Darensbourg, D. J.; Adams, M. J.; Yarbrough, J. C.; Phelps, A. L.
Eur. J. Inorg. Chem. 2003, 3639-48. Darensbourg, D. J.; Lee, W.-
Z.; Adams, M. J.; Yarbrough, J. C. Eur. J. Inorg. Chem. 2001, 2811-
22.
(26) For leading references, see Trofimenko, S. Polyhedron 2004, 23, 197-
203.
(27) Brown, H. C.; Ravindran, N.; Kulkarni, S. U. J. Org. Chem. 1980,
45, 384-9.
(28) Lancaster, S. J.; Walker, D. A.; Thorton-Pett, M.; Bochmann, M. Chem.
Commun. 1999, 1533-4.
(29) Williams, D.; Kouvetakis, J.; O’Keefe, M. Inorg. Chem. 1998, 37,
4617-20.
Inorganic Chemistry, Vol. 44, No. 18, 2005 6261

Yao et al.
[K(18-crown-6)][PhB(CN)3]. A finely ground sample of 5.21
g (80 mmol) of KCN in a 1-L flask was dried at 100 °C under
dynamic vacuum for 20 h. The cooled sample was treated with a
solution of 6.1 g (23.1 mmol) of 18-crown-6 in 350 mL of THF.
This mixture was refluxed for 20 h, cooled to 0 °C, and then treated
with a solution of 2.66 mL (20 mmol) of PhBCl2 in 80 mL of cold
(0 °C) THF. The reaction mixture was heated at reflux for 72 h
and then allowed to cool. The resulting reaction mixture was filtered
through Celite in air. The filtrate was evaporated to dryness, and
the resulting crude solid was washed with Et2O. Approximately 7
g of crude material was extracted into 10 mL of CH2Cl2, and this
solution was passed through a 15 × 2.5 cm column of acidic
alumina (activity 90, 70-230 mesh) followed by a washing with a
further 200 mL of CH2Cl2. The filtrate was evaporated to dryness,
and the residue was recrystallized by extraction into 10 mL of
MeCN followed by the addition of 80 mL of Et2O. Yield: 5.95 g
rings on one sheet are staggered with respect to the next,
allowing the Cu-NCMe groups to penetrate the hexagonal
rings.
Materials and Methods
General. Standard Schlenk techniques were employed in all
syntheses. PhBCl2, octBCl2, BuGaCl2,30 MesGaCl2,31 Me2S‚BHBr2,
and AgCN were prepared according to literature methods or
purchased from Aldrich. The purity of the 18-crown-6 is important
in reactions involving borane precursors. PPN[HB(CN)3] was
prepared by a modification of the published procedure. Other
synthetic protocols have been previously described.32 Elemental
analyses were conducted by the School of Chemical Sciences
1
Microanalytical Laboratory. 11B, 13C, and H NMR spectra were
acquired on Varian Unity 300, 400, and 500 NMR spectrometers.
Infrared spectra were acquired on a Mattson Infinity Gold FTIR
spectrometer using CaF2 solution cells or with KBr pellets.
Electrospray ionization mass spectrometry (ESI-MS) and MS-MS
measurements were acquired using a Micromass Quattro QHQ
quadrupole-hexapole-quadrupole instrument.
Ag[HB(NC)3]. In an adaptation of the procedure from Gyo¨ri et
al.,18 a solution of 5.880 g (25.17 mmol) of Me2S‚BHBr2 in 15 mL
of Me2S was added dropwise to an ice-cooled solution of 10.107
g (75.51 mmol) of AgCN in 40 mL of Me2S. The slurry was stirred
overnight, and the resulting gray solid was collected on a medium-
porosity frit. The orange filtrate was diluted with 100 mL of Et2O
to precipitate a white powder, which was collected on the same
frit. The combined gray solid was suspended in 300 mL of H2O. A
solution of 3.272 g (50.34 mmol) of KCN in 150 mL of H2O was
added over the course of 30 min. The resulting slurry was sonicated,
and the fine white powder of the desired product was then collected
on a medium-porosity frit. Yield: 4.89 g (98%). IR (KBr, cm-1):
νCN ) 2185, νBH ) 2482. Anal. Calcd for C3H1N3AgB (found):
C, 18.22 (23.99); H, 0.51 (1.89); N, 21.25 (18.35). This impure
material was used in the next step.
1
(63%). H NMR (CD3CN): δ 7.49 (m, 2H, C6H5), 7.29 (m, 2H,
C6H5), 7.22 (m, 1H, C6H5), 3.55 (s, 24H, OCH2CH2O). 13C NMR
(CD3CN): δ 133 (C6H5), 129 (C6H5), 128 (C6H5), 129-131 (q,
JB-C ) 65 Hz, CN), 70.7 (OCH2CH2O). 11B NMR (CDCl3): δ
-28.5 (s). ESI-MS: m/z 166.1. IR (CH3CN, cm-1): νCN ) 2135.
Anal. Calcd for C21H29N3BKO6 (found): C, 53.74 (53.35); H, 6.23
(6.22); N, 8.95 (8.82).
Et4N[PhB(CN)3]. A suspension of 1.69 g (10.8 mmol) of
Et4NCN in 60 mL of THF was treated with a solution of 0.48 mL
(3.6 mmol) of PhBCl2 in 30 mL of cold (0 °C) THF. The reaction
mixture was heated at reflux for 70 h and then allowed to cool.
The resulting reaction mixture was filtered through Celite in air.
The filtrate was evaporated to dryness, and the resulting crude solid
was washed with Et2O and then extracted with 10 mL of acetone.
The acetone extract was concentrated to ∼5 mL and then diluted
with 20 mL of H2O to precipitate a yellow solid. The crude product
was dried under a vacuum and crystallized from MeCN-Et2O.
Approximately 450 mg of crude material was extracted into 2 mL
of CH2Cl2, and this solution was passed through a 15 × 2.5 cm
column of acidic alumina (activity 90, 70-230 mesh) followed by
a washing with a further 60 mL of CH2Cl2. The filtrate was
evaporated to dryness, and the residue was recrystallized by
extraction into 4 mL of MeCN by the addition of 30 mL of Et2O.
PPN[HB(NC)3]. A solution of 2.979 g (12.42 mmol) of Na2S‚
9H2O in 100 mL of H2O was added dropwise to a solution of 4.891
g (24.81 mmol) of crude Ag[HB(NC)3] in 100 mL of H2O. The
resulting gray-black slurry was stirred for 4 h before filtering off
the black Ag2S. The filtrate was concentrated to 30 mL and treated
with a solution of 14.221 g (24.81 mmol) of PPNCl in 3 L of H2O.
The resulting white precipitate was collected by filtration and air-
1
Yield: 0.23 g (22%). H NMR (CD3CN): δ 7.48 (m, 2H, C6H5),
7.29 (t, 2H, C6H5), 7.22 (t, 1H, C6H5), 3.13 (q, 8H, CH2), 1.18 (m,
12H, CH3). 13C NMR (CD3CN): δ 133.4 (C6H5), 139.5-141.2 (q,
C6H5, JBC ) 56 Hz), 129.0-131.0 (q, CN, JBC ) 66 Hz), 129.0
(C6H5), 127.8 (C6H5), 52.9 (CH2), 7.6 (CH3). 11B NMR (CDCl3):
δ -28.6 (s). ESI-MS: m/z 166.1 (M-), 130.5 (M+). IR (KBr, cm-1):
νCN ) 2203, 2212. Anal. Calcd for C17H25N4B (found): C, 68.93
(68.83); H, 8.51 (8.63); N, 18.91 (18.47).
1
dried. Yield: 9.451 g (61%). H NMR (THF): δ 2.56 (q, 1H),
7.64 (m, 30H). 11B NMR (CD3CN): δ -20.1. ESI-MS: m/z 90.4.
IR (KBr, cm-1): νCN ) 2128, νBH ) 2446. Anal. Calcd for
C39H31N4BP2 (found): C, 74.54 (73.24); H, 4.97 (4.87); N, 8.92
(8.24).
[K(18-crown-6)][octB(CN)3]. A 500 mL flask was charged with
3.65 g (56 mmol) of finely powdered KCN and heated at 100 °C
under a vacuum for 18 h. After cooling to ambient temperature,
the flask was charged further with 4.1 g (15.5 mmol) of 18-crown-6
and 250 mL of THF. The mixture was stirred at reflux for 10 h
and then cooled to 0 °C. A solution of 2.8 g (14.4 mmol) of octBCl2
in 70 mL of THF (0 °C) was added, and the reaction mixture was
brought to reflux. After 72 h, the cooled reaction mixture was
filtered through Celite in air. Evaporation of the filtrate gave an
oily residue, which was extracted with 100 mL of Et2O, the
evaporation of which gave a light yellow oil, which was washed
with hexane several times. A solution of the crude oil in 5 mL of
CH2Cl2 was passed through a 15 cm column of alumina, eluting
with 1:6 hexane-CH2Cl2. Evaporation of the eluate gave a white
solid, which was recrystallized from Et2O-hexane. Yield: 3.3 g
(44%). 1H NMR (500 MHz, CD3CN): δ 3.56 (s, 24H, OCH2CH2O),
PPN[HB(CN)3]. A suspension of 5.230 g (1.211 mmol) of the
aforementioned, slightly impure PPN[HB(NC)3] in 100 mL of Bu2O
was heated to 120 °C, while open to air to allow the evaporation
of H2O. The flask was then fitted with a water-cooled condenser,
and the solution was heated at reflux for 24 h. The cooled slurry
1
was filtered on a medium porosity frit. Yield: 5.121 g (98%). H
NMR (THF): δ 1.76 (q, 1H), 7.63 (m, 30H). 11B NMR (CD3CN):
δ -40.16. ESI-MS: m/z 90.4. IR (KBr, cm-1): νCN ) 2209, νBH
) 2393. Anal. Calcd for C39H31N4BP2 (found): C, 74.54 (74.28);
H, 4.97 (4.91); N, 8.92 (8.85).
(30) Kovar, R. A.; Loaris, G.; Derr, H.; Callaway, J. O. Inorg. Chem. 1974,
13, 1476-9.
(31) Beachley, O. T., Jr.; Churchill, M. R.; Pazik, J. C.; Ziller, J. W.
Organometallics 1987, 6, 2088-93.
(32) Kuhlman, M. L.; Rauchfuss, T. B. Inorg. Chem. 2004, 43, 430-35.
6262 Inorganic Chemistry, Vol. 44, No. 18, 2005

Organo-Tricyanoborates as Tectons
Table 1. Crystallographic Data for Et4N[MesGa(CN)3], 2[PhB(CN)3]2Cu(NCMe)]‚MeCN, Cu[PhB(CN)3]2[K(C12H24O6)](CH3CN),
[octB(CN)3Cu(NCMe)]‚MeCN, and [PhB(CN)3Cu(PCy3)2
parameter
Et4N[mesGa(CN)3]
C20H31GaN4
2[PhB(CN)3]2Cu(NCMe)]‚MeCN
Cu[PhB(CN)3]2[K(C12H24O6)]‚MeCN
chemical formula
T (K)
C24H19B2Cu2N9
193(2)
C37H19B2CuKN7O6
193(2)
193(2)
cryst. size (mm3)
space group
a (Å)
0.48 × 0.46 × 0.01
0.27 × 0.18 × 0.10
0.08 × 0.10 × 0.60
Pbca
Pm
pbca
10.442(2)
15.998(4)
25.863(6)
90
90
90
4320.5(16)
8
1.221
1.283
45 788/3967
8.464(5)
7.613(5)
13.176(8)
90
90.482(9)
90
849(9)
1
1.139
1.277
13.387(2)
15.805(3)
35.961(6)
90
90
90
7609(2)
8
1.292
0.732
60 872/6975
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
D
calcd (mg m-3
)
µ (Mo KR, mm-1
reflns measured/
independent
)
8816/3328
data/restraints/params
GOF
3967/0/234
1.021
3328/57/111
0.919
6975/0/443
1.021
Rint
0.0511
0.1809
0.0783
R1 [I > 2σ] (all data)a
wR2 [I > 2σ] (all data)b
max. peak/hole (e-/Å3)
descriptor
0.0285 (0.0488)
0.0779 (0.0850)
0.381/-0.225
[octB(CN)3Cu(NCMe)]‚MeCN
0.0948 (0.2367)
0.2165 (0.2699)
1.437/-0.529
[PhB(CN)3Cu(PCy3)2]
0.0398 (0.0734)
0.0837 (0.0934)
0.378/-0.207
parameter
Et4N[mesGa(CN)3]
2[PhB(CN)3]2Cu(NCMe)]‚MeCN
chemical formula
T (K)
C15H23BCuN5
193(2)
C45H71BCuN3P2
293(2)
cryst. size (mm3)
space group
a (Å)
0.48 × 0.46 × 0.01
0.60 × 0.10 × 0.03
C2/m
P2(1)/n
12.874(4)
7.821(3)
21.225(7)
90
106.493(5)
90
2049.3(12)
4
1.127
14.591(9)
14.190(8)
21.788(12)
90
98.372(11)
90
4463(4)
4
1.176
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
D
calcd (mg m-3
)
µ (Mo KR, mm-1
reflns measured/
independent
)
1.068
8122/2020
0.594
35 624/8201
data/restraints/params
GOF
2020/178/215
0.969
8201/398/637
0.954
Rint
0.0939
0.1149
R1 [I > 2σ] (all data)a
wR2 [I > 2σ] (all data)b
max peak/hole (e-/Å3)
0.0492 (0.0860)
0.0996 (0.1095)
0.525/-0.258
0.0529 (0.1217)
0.0988 (0.1186)
0.366/-0.336
a R1 ) ∑||Fo|-|Fc||/∑|Fo|. b wR2 ) {∑[w(Fo -Fc )2]/∑[w(Fo )2]}1/2
.
2
2
2
1.28 (m, 12H, Me(CH2)7B), 0.87 (t, 3H, CH3(CH2)7B), 0.42 (t, 2H,
Me(CH2)7B). 13C NMR (CD3CN): δ 130.1-131.5 (q, BCN), 70.9
(OCH2CH2O), 33.5, 32.6, 30.3, 30.1, 28.5, 27.2, 23.3, 14.4 (octyl).
11B NMR (96.3 MHz, CDCl3): δ -30.2 (s). ESI-MS: m/z 202.2
(M-), 303.4 (M+). IR (CH3CN, cm-1): νCN ) 2132. Anal. Calcd
for C23H41N3BKO6 (found): C, 54.65 (54.55); H, 8.18 (8.26); N,
8.31 (8.11).
Et4N[PhB(NC)3]. To a solution of 9.1 g (67.8 mmol) of AgCN
in 35 mL of Me2S was slowly added a solution of 3.58 g (22.6
mmol) of PhBCl2 in 10 mL of Me2S at 0 °C. After stirring the
mixture at room-temperature overnight, the solids were filtered off.
The yellow filtrate was added dropwise to 25 mL of diglyme at 80
°C over the course of 2 h and using a fast N2 stream to remove the
Me2S. The pale powder was collected by filtration and washed with
Et2O. A suspension of the solid in 10 mL of H2O was added to a
solution of 3.52 g of KCN (54 mmol) in 5 mL of H2O. After 15
min, the product was collected by filtration, washed with 5 mL of
H2O, and dried under a vacuum at 100 °C to give 5.85 g of colorless
AgPhB(NC)3. To a suspension of the entire portion of AgPhB-
(NC)3 in 20 mL of H2O was added 2.57 g (21.4 mmol) of Na2S‚
9H2O in 20 mL of H2O. After stirring overnight, the suspension
was filtered to remove black Ag2S. To this filtrate was added a
solution of 3.6 g (17.12 mmol) of Et4NBr in 10 mL of H2O. The
resulting white solid was collected by filtration, washed with H2O,
and crystallized with acetone/H2O to give colorless crystals.
Yield: 2.2 g (33%). 1H NMR (500 MHz, CDCl3): δ 7.64 (d, 2H,
C6H5), 7.30 (t, 2H, C6H5), 7.26 (t, 1H, C6H5), 3.07 (q, 8H,
MeCH2N), 1.23 (m, 12H, CH3CH2N). 13C NMR (125.7 MHz,
CDCl3): δ 165.6 (CN), 142.0 (broad, BC6H5), 130.4 (C6H5), 127.2
(C6H5), 51.8 (CH2), 6.8 (CH3). 11B NMR (96.3 MHz, CDCl3): δ
-13.4 (s). ESI-MS: m/z 166.5 (M-), 130.5 (M+). IR (KBr, cm-1):
νCN ) 2145, 2126. Anal. Calcd for C17H25N4B (found): C, 68.93
(68.53); H, 8.51 (8.55); N, 18.91 (18.44).
[PhB(CN)3Cu(PCy3)2]. A solution of 218 mg (0.833 mmol) of
PCy3 in 10 mL of MeCN was added dropwise to a solution of 155
mg (0.417 mmol) of [Cu(NCMe)4]PF6 in 5 mL of MeCN. After 1
h, this solution was treated with a solution of 196 mg (0.417 mmol)
of [K(18-crown-6)][PhB(CN)3] in 10 mL of MeCN, resulting in
Inorganic Chemistry, Vol. 44, No. 18, 2005 6263

Yao et al.
the immediate formation of a white precipitate. The solid was
collected by filtration and washed with 20 mL of MeCN. Yield:
256 mg (82%). 1H NMR (500 MHz, THF): δ 1.34 (m, 31H), 1.83
(m, 31H), 7.16 (m, 1H), 7.22 (m, 2H), 7.53 (m, 2H). 31P NMR
(125.7 MHz, THF): δ 16.2, 14.7. IR (KBr, cm-1): νCN ) 2173,
2129. Anal. Calcd for C45H71N3BCuP2 (found): C, 68.38 (67.56);
H, 9.05 (9.14); N, 5.32 (5.49). Crystals were obtained by layering
a solution of 30 mg of [PhB(CN)3Cu(PCy3)2] in 3 mL of THF with
8 mL of hexanes.
C6D6): δ 2.40 (q, J ) 7 Hz, 8H, MeCH2N), 1.74 [m, 2H, Me-
(CH2)3Ga], 1.47 [m, 2H, J ) 7.5 Hz, CH3(CH2)3Ga], 0.92 [t, 3H,
J ) 7.5 Hz, CH3(CH2)3Ga], 0.73 [t, 2H, J ) 8 Hz, CH3(CH2)3Ga],
0.68 (m, 12H, CH3CH2N). 13C NMR (125.6 MHz, d8-THF): δ
131.8 (CN), 53.01 (Et4N), 29.4, 27.7, 14.2 (Bu), 9.7 [Me(CH2)2CH2-
Ga], 7.7 (Et4N). ESI-MS: m/z 204.2 (M-). IR (THF, cm-1): νCN
) 2169. Anal. Calcd for C15H29N4Ga (found): C, 53.76 (53.14);
H, 8.72 (8.67); N, 16.72 (16.59).
Et4N[mesGa(CN)3]. A 500 mL flask was charged with 4.69 g
(30 mmol) of Et4NCN in 250 mL of THF followed by a solution
of 2.60 g (10 mmol) of mesityl GaCl2 in 50 mL of THF. The
reaction mixture was heated to reflux. After 9 days, the reaction
mixture was allowed to cool to room temperature and was then
filtered under nitrogen. The filtrate was concentrated to ∼80 mL
under a vacuum, and the resulting solid was filtered off. The volume
of filtrate was further concentrated to 20 mL before being diluted
with 100 mL of Et2O, which precipitated a colorless solid, which
[PhB(CN)3Cu(NCMe)]. A solution of 80 mg (0.214 mmol) of
[Cu(NCMe)4]PF6 in 10 mL of MeCN was added dropwise to a
solution of 100 mg (0.214 mmol) of [K(18-crown-6)][PhB(CN)3]
in 10 mL of MeCN. The resulting colorless precipitate was collected
by filtration and washed with MeCN. Yield: 49 mg (85%). IR (KBr,
cm-1): νCN ) 2173. Anal. Calcd for C11H8N4BCu (found): C, 48.83
(47.69); H, 2.98 (2.50); N, 20.70 (18.34). Crystals were obtained
by refluxing 30 mg of [PhB(CN)3Cu(NCMe)] in 10 mL of MeCN
followed by slowly cooling this solution to room temperature.
[K(18-crown-6)]Cu[PhB(CN)3]2. A solution of 141 mg (0.3
mmol) of [K(18-crown-6)][PhB(CN)3] in 10 mL of MeCN was
added dropwise to a solution of 56 mg (0.15 mmol) of [Cu(NCMe)4]-
PF6 in 10 mL of MeCN. After stirring for 4 h, the reaction solution
was concentrated to ∼5 mL, and this solution was layered with 10
mL of Et2O. Colorless needlelike crystals formed over the course
1
was collected by filtration. Yield: 3.05 g (77%). H NMR (500
MHz, d8-THF): δ 6.72 (s, 2H, C6H2), 3.29 (q, J ) 7 Hz, 8H,
MeCH2N), 2.47 (s, 6H, ArCH3), 2.19 (s, 3H, ArCH3), 1.28 (m,
12H, CH3CH2N). 13C NMR (125.6 MHz, d8-THF): δ 145.8, 138.2,
135.5 (CN), 133.0, 128.2, 53.01 (Et4N), 21.2 (CH3 of ArCH3), 7.6
(Et4N). ESI-MS: m/z 266.4 (M-). IR (THF, cm-1): νCN ) 2170.
Anal. Calcd for C20H31N4Ga (found): C, 60.48 (59.46); H, 7.87
(7.82); N, 14.11 (13.31).
1
of 72 h. Yield: 86 mg (82%). H NMR (500 MHz, CD3CN): δ
3.56 (s, 24H), 7.23 (m, 2H), 7.30 (m, 4H), 7.47 (m, 4H). IR (KBr,
cm-1): νCN ) 2164. Anal. Calcd for C30H34N6B2CuKO6 (found):
C, 51.56 (51.68); H, 4.90 (4.90); N, 12.02 (12.95). Single crystals
were obtained upon addition of Et2O to the MeCN solution.
[octB(CN)3Cu(NCMe)]. A solution of 192 mg (0.515 mmol)
of [Cu(NCMe)4]PF6 in 15 mL of MeCN was added dropwise to a
solution of 260 mg (0.515 mmol) of [K(18-crown-6)][octB(CN)3]
in 15 mL of MeCN, resulting in the immediate precipitation of a
white solid, which was filtered and washed with MeCN. Yield:
121 mg (77%). IR (KBr, cm-1): νCN ) 2167. Anal. Calcd for
C13H20N4BCu (found): C, 50.91 (50.15); H, 6.57 (6.46); N, 18.26
(17.42). Crystals were obtained by extracting 30 mg of [octB-
(CN)3Cu(NCMe)] with 10 mL of MeCN followed by slowly cooling
the extract to room temperature.
Crystallography. Crystals were mounted on thin glass fibers
using Paratone-N oil (Exxon) before being transferred to a Siemens
Platform/CCD automated diffractometer for data collection. Data
processing was performed with SAINT PLUS, version 6.22.
Structures were solved using direct methods and refined using full-
matrix least squares on F2 using the Bruker program SHELXTL,
version 6.10. Hydrogen atoms were fixed in idealized positions with
thermal parameters 1.5× those of the attached carbon atoms. The
data were corrected for absorption on the basis of Ψ scans. Details
for each crystal are given in Table 1.
Acknowledgment. This research was supported by the
Department of Energy.
Et4N[BuGa(CN)3]. A 500 mL flask was charged with a solution
of 6.41 g of Et4NCN (41 mmol) in 200 mL of THF followed by a
solution of 2.685 g (13.6 mmol) of BuGaCl2 in 30 mL of THF.
The reaction mixture was heated to reflux. After 4.5 days, the
reaction mixture was allowed to cool to room temperature and was
filtered under nitrogen. The filtrate was evaporated under a vacuum,
and the oily residue was washed with two 30 mL portions of Et2O
and dried under a vacuum. Yield: 4 g (88%). 1H NMR (500 MHz,
Supporting Information Available: Crystallographic files
(CIF) for Et4N[mesGa(CN)3], [PhB(CN)3Cu(NCMe)], [octB(CN)3Cu-
(NCMe)], [PhB(CN)3Cu(PCy3)2], and [K(18-crown-6)]{Cu-
[PhB(CN)3]2} (see also CCDC 253992-253995 and 264411). This
material is available free of charge via the Internet at
http://pubs.acs.org.
IC0506153
6264 Inorganic Chemistry, Vol. 44, No. 18, 2005