Crystal structures of a series of complexes produced by reaction of copper(I) cyanide with diamines

Article abstract of DOI:10.1021/ic970226b

A new synthetic procedure developed recently in our laboratories has made possible the synthesis of variety of new complexes of CuCN with diamines. Synthesis was effected by adding the ligand to a solution of CuCN in aqueous sodium thiosulfate. This procedure also provides an alternative pathway to a novel diamine complex reported by us previously, (CuCN)₃(HMTA)₂ (1) (where HMTA = hexamethylenetetramine). The other diamine ligands used were l,4-diazabicyclo[2.2.2]octane (dabco), 1,4-dimethylpiperazine (dmpip), piperazine (pip), 1,4-butanediamine (butda), N,N,N',N,-tetramethylethylenediamine (tetmen), and N-phenylpiperazine (phpip). Complex 2, Cu₂(CN)₃(dabco-H), crystallizes in the hexagonal space group P6₃ with unit cell dimensions a = 8.174(3) ?, c = 8.083(4) A ?, and Z = 2. Complex 3, (CuCN)₂(dmpip), crystallizes in the monoclinic space group C2/m with unit cell dimensions a = 8.812(3) ?, b = 9.631(2) ?, c = 7.266(3) ?, β= 113.40(3)°, and Z = 2. Complex 4, (CuCN)₂(pip), crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 9.439(3) ?, b = 10.561(2) ?, c = 8.870(3) ?, β= 98.32(3)°, and Z = 4. Complex 5, Cu₂(CN)₃(pip-H), crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.573(9) ?, b = 8.354(2) ?, c = 15.989(6) ?, β= 133.70(3)°, and Z = 8. Complex 6, (CuCN)₂(butda), crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 10.456(2) ?, b = 5.550(1) A, c = 8.669(3) ?, β= 106.80(2)°, and Z = 2. Complex 7, (CuCN)₂(tetmen), crystallizes in the orthorhombic space group Cmc2₁ with unit cell dimensions a = 11.889(4) ?, b -33.380(8) ?, c = 9.012(3) ?, and Z = 12. Complex 8, (CuCN)(phpip), crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 17.8819(3) ?, b = 6.9190(1) ?, c = 8.6972(1) ?, β= 96.720(1)°, and Z = 4.

Full text of DOI:10.1021/ic970226b

9
84
Inorg. Chem. 1999, 38, 984-991
Crystal Structures of a Series of Complexes Produced by Reaction of Copper(I) Cyanide
with Diamines
†
‡
§
Fred B. Stocker,* Teodora P. Staeva, Chad M. Rienstra, and Doyle Britton
Departments of Chemistry, Macalester College, St. Paul, Minnesota 55105, and University of Minnesota,
Minneapolis, Minnesota 55455
ReceiVed February 26, 1997
A new synthetic procedure developed recently in our laboratories has made possible the synthesis of variety of
new complexes of CuCN with diamines. Synthesis was effected by adding the ligand to a solution of CuCN in
aqueous sodium thiosulfate. This procedure also provides an alternative pathway to a novel diamine complex
reported by us previously, (CuCN)3(HMTA)2 (1) (where HMTA ) hexamethylenetetramine). The other diamine
ligands used were 1,4-diazabicyclo[2.2.2]octane (dabco), 1,4-dimethylpiperazine (dmpip), piperazine (pip), 1,4-
butanediamine (butda), N,N,N′,N′-tetramethylethylenediamine (tetmen), and N-phenylpiperazine (phpip). Complex
2
, Cu2(CN)3(dabco-H), crystallizes in the hexagonal space group P63 with unit cell dimensions a ) 8.174(3) Å,
c ) 8.083(4) Å, and Z ) 2. Complex 3, (CuCN)2(dmpip), crystallizes in the monoclinic space group C2/m with
unit cell dimensions a ) 8.812(3) Å, b ) 9.631(2) Å, c ) 7.266(3) Å, â ) 113.40(3)°, and Z ) 2. Complex 4,
(
1
CuCN)2(pip), crystallizes in the monoclinic space group C2/c with unit cell dimensions a ) 9.439(3) Å, b )
0.561(2) Å, c ) 8.870(3) Å, â ) 98.32(3)°, and Z ) 4. Complex 5, Cu2(CN)3(pip-H), crystallizes in the monoclinic
space group C2/c with unit cell dimensions a ) 20.573(9) Å, b ) 8.354(2) Å, c ) 15.989(6) Å, â ) 133.70(3)°,
and Z ) 8. Complex 6, (CuCN)2(butda), crystallizes in the monoclinic space group P21/c with unit cell dimensions
a ) 10.456(2) Å, b ) 5.550(1) Å, c ) 8.669(3) Å, â ) 106.80(2)°, and Z ) 2. Complex 7, (CuCN)2(tetmen),
crystallizes in the orthorhombic space group Cmc21 with unit cell dimensions a ) 11.889(4) Å, b ) 33.380(8)
Å, c ) 9.012(3) Å, and Z ) 12. Complex 8, (CuCN)(phpip), crystallizes in the monoclinic space group P21/c
with unit cell dimensions a ) 17.8819(3) Å, b ) 6.9190(1) Å, c ) 8.6972(1) Å, â ) 96.720(1)°, and Z ) 4.
Introduction
Scheme 1
In 1991, we reported the synthesis and X-ray crystal structure
of a new complex of copper(I) cyanide and hexamethylene-
1
tetramine (C6H12N4, HMTA). The preparation of this complex,
(
Scheme 2
CuCN)3(HMTA)2 (1), which was discovered by accident, came
about during an attempt to prepare imidazoles by reacting sugars
with Cu(II) salts, ammonia, and formaldehyde (Parrod synthe-
sis). The formation of 1 occurred in the absence of sugars
of CuCN and diamines have been reported. Two such com-
plexes, based on the 1,10-phenanthroline (phen) system, are
CuCN(phen) and CuCN(dmphen) (where dmphen ) 2,9-
(Scheme 1).
It is noteworthy that none of the constituents (the Cu(I), the
2
CN, or the HMTA) of the product was present in the starting
materials. All attempts at synthesis of 1 by direct combinations
of CuCN and HMTA in various solvents failed.
dimethyl-1,10-phenanthroline). Another involving hydrazine
3
(the limiting diamine) is CuCN(N2H4). Ethylenediamine (en)
is present in a mixed Cu(II)/Cu(I) complex with the composition
4
A synthetic method recently developed in our laboratories
provided an alternative pathway to 1. This method, which is
widely applicable, consists of “thiosulfate-assisted” direct
combinations of CuCN and water-soluble organic ligands. The
weak complex of CuCN/S2O32 has a strong tendency to release
CuCN to virtually any water soluble ligand (L), thus producing
a new complex of CuCN/L. Scheme 2 shows how this technique
was used in the new preparation of 1.
Cu(II)Cu(I)2(CN)4(en)2(H2O). The phen and hydrazine com-
plexes were synthesized by direct combination of CuCN and
the neat ligand, whereas the en complex was prepared by
dissolving CuCN in 50% aqueous ethylenediamine. For pro-
spective diamine ligands that are solids (e.g., HMTA) or that
are liquids that fail to exhibit dissolving power for CuCN, the
thiosulfate-assisted synthesis provides a powerful new synthetic
approach. We, therefore, set out to use this method to prepare
a variety of new diamine complexes of CuCN.
-
This method is appropriate for a variety of amines, but this
paper will focus entirely on diamines. Only a few complexes
This study covered a variety of diamines, including bicyclic,
cyclic, acyclic, primary, secondary, and tertiary types. Also, a
*
To whom correspondence should be addressed.
Present address: Department of Immunology, Cornell University
†
(2) Dyason, J. C.; Healy, P. C.; Engelhardt, L. M.; Pakawatchai, C.;
Patrick, V. A.; White, A. H. J. Chem. Soc., Dalton Trans. 1985, 839.
(3) Cromer, D. T.; Larson, A. C.; Roof, R. B. Acta Crystallogr., Sect. B
1966, 20, 279.
(4) Williams, R. J.; Larson, A. C. Cromer, D. T. Acta Crystallogr., Sect.
B 1972, 28, 858.
Medical School, New York, NY.
‡
Present address: Department of Chemistry, Massachusetts Institute of
Technology, Cambridge, MA 02139.
§
University of Minnesota.
(
1) Stocker, F. B. Inorg. Chem. 1991, 30, 1472.
1
0.1021/ic970226b CCC: $18.00 © 1999 American Chemical Society
Published on Web 02/11/1999

Complexes Produced by Reaction of CuCN with Diamines
Inorganic Chemistry, Vol. 38, No. 5, 1999 985
Scheme 3
and washed with distilled water. All preparations were carried out in
the presence of air, and all of the new compounds reported have proven
to be stable in air for periods in excess of 1 year.
3 2
Preparation of (CuCN) (HMTA) (1). In a variation of the usual
preparation, hexamethylenetetramine (280 mg, 2 mmol) was dissolved
at room temperature in the “standard solution”. Within minutes, a white
precipitate formed that was dissolved by swirling the flask over a steam
bath. The hot, essentially clear solution was filtered, corked, and set
aside on an insulated surface. Within a few hours, glistening micro-
crystals were evident. After 1 day, the bottom of the flask was covered
with colorless crystals, but the product was not isolated until the twelfth
day. By then the solution had taken on a very faint blue tint. The white
crystalline product (124 mg, 22.6%) gave an IR spectrum that was
identical to the IR spectrum of an authentic sample.
2 3
Preparation of Cu (CN) (dabco-H) (2). To the “standard solution”
was added 1,4-diazobicyclo[2.2.2]octane (112 mg, 1 mmol), which
dissolved with mild heating. After the colorless solution was heated to
8
8 °C and filtered, it was transferred to test tubes that were suspended
in a 40 °C water bath that was allowed to cool spontaneously to room
temperature. Crystals began to appear after the first few hours. The
product (pale pink crystals, 108 mg, 33.9%) was collected by filtration
after 2 days: IR 3420 br, w, 3020 s, 2955 w, 2770 w, 2608 w, 2130
w, 2075 s, 1620 br, w, 1465 w, 1450 m, 1392 s, 1372 w, 1312 m,
series of straight-chain diamines of the general structure H2N-
(CH2)nNH2 were explored, where n ) 3-6. In most cases, the
1
4
236 w, 1173 w, 1047 s, 1020 w, 987 w, 830 m, 795 s, 603 m, 595 w,
05 w cm . Anal. Calcd for C H13Cu N : C, 33.96; H, 4.12; Cu, 39.92;
9 2 5
diamines tested did produce insoluble solid complexes that gave
positive chemical tests for Cu and IR spectral evidence for both
CN and ligand. However, not all of these products were
stoichiometric and not all produced crystals suitable for X-ray
structure determinations. Scheme 3 shows the transformations
that led to the complexes whose crystal structures are reported
in this paper.
-1
N, 22.00. Found: C, 33.21, 33.82; H, 4.06, 4.14; Cu, 42.67, 42.43; N,
2
1.30, 21.82.
2
Preparation of (CuCN) (dmpip) (3). To 30 mL of the “standard
solution” was added 1,4-dimethylpiperazine (114 mg, 1 mmol).
Warming caused the ligand to dissolve, and after the temperature
reached about 80 °C, the colorless solution was filtered and then placed
in a 60 °C water bath. The water bath was allowed to cool slowly over
a period of several hours to room temperature. Crystal growth was
evident the next day, but the product was not collected for 5 days. The
colorless prisms amounted to 33 mg (11%): IR 3450 br, m, 2973 m,
The structures of the ligands are as follows:
2
950 w, 2890 w, 2815 m, 2760 w, 2705 w, 2140 s, 1670 br, w, 1630
br, w, 1455 s, 1422 w, 1377 w, 1297 m, 1158 m, 1128 w, 1100 w,
-
1
1
057 w, 1017 s, 917 w, 825 m, 638 w, 433 w cm . Anal. Calcd for
: C, 32.76; H, 4.81; Cu, 43.33; N, 19.10. Found: C, 32.08;
H, 4.88; Cu, 44.36; N, 18.83.
Preparation of (CuCN) (pip) (4). Piperazine hexahydrate (194 mg,
mmol) dissolved readily in the “standard solution” to give a clear
8 2 4
C H14Cu N
2
1
solution. After being heated on a hot plate to 85 °C, the solution took
on a light tan color, and a fine, dusty tan precipitate appeared. Filtration
produced a clear solution that was placed in an 80 °C water bath that
was allowed to cool slowly to room temperature. Crystal growth was
evident within 2 h. The following day, the first crop of product was
collected by filtration (predominantly clear prisms, with a few brown
present, 100 mg, 37.7%). The mother liquor later produced another
batch of crystals, which turned out to be 5 (see next preparation): IR
3
430 br, m, 3265 s, 2938 m, 2870 w, 2835 w, 2195 s, 2045 m, 1625
Experimental Section
br, w, 1455 m, 1443 w, 1323 m, 1282 w, 1108 s, 1093 m, 997 m, 860
s, 627 m cm . Anal. Calcd for C H10Cu N : C, 27.17; H, 3.80; Cu,
6 2 4
47.91; N, 21.12. Found: C, 26.94.; H, 3.88; Cu, 48.09; N, 21.36.
Found: C, 27.26.; H, 4.63; Cu, 45.51; N, 20.92.
-
1
General Methods. Commercial chemicals were used without further
purification. Infrared spectra were recorded as KBr pellets with a Perkin-
Elmer model 1430. Except where noted, all elemental analyses were
determined by Galbraith Laboratories, Knoxville, TN. The crystal
structures were determined by the X-ray Service Laboratory, Depart-
ment of Chemistry, University of Minnesota, Minneapolis, MN.
General Methods of Preparation. To prepare crystals of sufficient
size for X-ray structure determinations, the following standard procedure
was used. Copper(I) cyanide (270 mg, 3 mmol) was added to a solution
5
2 3
Preparation of Cu (CN) (pip-H) (5). The mother liquor from the
previous experiment produced a second crop of crystals over a 3 day
period at room temperature (thick brown diamond shaped plates, 20
mg, 6.8%). Anal. Calcd for C H11Cu N : C, 28.77; H, 3.79; Cu, 43.48;
7 2 5
N, 23.96. Found: C, 28.64; H, 3.75: Cu, 43.84; N, 23.99. We have
found in other preparations using the same procedure with piperazine
that a delay in collection of the product increases the proportion of 5
produced relative to 4. For example, filtration after 11 days produced
a product mixture consisting of 80 mg of large brown diamond-shaped
crystals (5), easily separated from 40 mg of small white crystals (4):
IR 3250 m, 3165 w, 3110 w, 3040 s, 2810 w, 2625 w, 2440 w, 2110
s, 1670 br, w, 1580 s, 1460 m, 1447 m, 1410 m, 1387 m, 1298 w,
1200 w, 1110 m, 1060 w, 1027 w, 995 m, 973 s, 880 w, 867 m, 815
prepared by dissolving Na
2
S
2
O
3
2
‚5H O (2.482 g, 10 mmol) in 30 mL
of distilled water (this is called the “standard solution”). After the CuCN
dissolved, the ligand was added (1.0 mmol), and the mixture was heated
and stirred until clear. The hot solution was filtered by gravity, and
except where noted, the filtrate was poured into several small test tubes
(
13 mm × 100 mm) that were immersed in a hot water (400 mL) bath.
The bath was either held at elevated temperatures for several hours on
a steam cone or allowed to cool spontaneously on an insulated surface.
After crystal growth appeared to be complete (rate of crystal growth
dependent upon ligand), the crystals were collected by suction filtration
-
1
w, 600 w, 466 m, 425 w cm
.
(5) This analysis was performed by M-H-W Laboratories, Phoenix, AZ.

986 Inorganic Chemistry, Vol. 38, No. 5, 1999
Stocker et al.
Table 1. Crystallographic Dataa
complex no.
formula
fw
space group
a, Å
b, Å
c, Å
2
C
3
C
4
C
5
C
6
C
7
C
8
9
H
13Cu
2
N
5
8
H14Cu
2
N
4
6
H10Cu
2
N
4
7
H11Cu N
2 5
6
H
12Cu
N
2 4
8
H
16Cu
2
N
4
11 3
C H13CuN
250.78
P2 /c (No. 14)
17.8819(3)
6.9190(1)
8.6972(1)
90
96.720(1)
90
1068.67(3)
4
1.559
20.11
25
318.33
P6 (No. 173)
8.714(3)
293.32
265.26
292.29
267.28
P2 /c (No. 14)
10.456(2)
5.550(1)
8.669(3)
90.0
106.80(2)
90.0
481.6(4)
2
1.843
43.84
25
0.028
0.031
295.34
Cmc2
11.889(4)
33.380(8)
9.012(3)
90.0
90.0
90.0
3576(3)
12
1.645
35.50
24
3
C2/m (No 12)
8.812(3)
9.631(2)
7.266(3)
90.0
113.40(3)
90.0
566.0(7)
2
1.721
37.38
24
0.033
0.039
C2/c (No. 15)
9.439(3)
10.561(2)
8.870(3)
90.0
98.32(3)
90.0
874.9(8)
4
2.014
48.26
24
0.029
0.032
C2/c (No. 15)
20.573(9)
8.354(2)
15.989(6)
90.0
133.70(3)
90.0
1987(3)
8
1.954
42.62
24
0.043
0.039
1
1
(No. 36)
1
8.083(4)
90.0
90.0
120.0
531.5(6)
2
1.989
39.91
24
R, deg
â, deg
γ, deg
3
V, Å
Z
F
calcd (g cm-3)
-
1
µ, cm
T, °C
b
R
R
0.030
0.038
0.068
0.057
0.0321
0.0927
c
w
a
Radiation: Mo KR(graphite monochromated, λ ) 0.710 73). b R ) ∑||F
c
2
2)]1/2.
o
o
| - |F
c
||/∑|F
o
|.
R
w
) [(∑w(|F
o
| - |F
c
|) /∑wF
Preparation of (CuCN)
2
(butda) (6). Upon dissolving 1,4-diamino-
1398 w, 1310 w, 1280 w, 1175 m, 1093 w, 1053 w, 1023 m, 953 w,
900 m, 883 w, 665 m, 625 w, 495 w, 360 w. Anal. Calcd for C
Cu : C, 23.71; H, 3.98; Cu, 50.18; N, 22.12. Found: C, 23.14; H,
butane (88 mg, 1 mmol) in 30 mL of the “standard solution”, a blue
color appeared. After the solution was heated to 70 °C, the color faded,
changing from blue to pale green and eventually a faint yellow color.
The hot solution was filtered and placed in a 70 °C water bath that
was allowed to cool to room temperature. The following day, the
crystals (colorless prisms, 133 mg, 50%) were collected by filtration:
IR 3420 br, m, 3115 s, 3275 s, 2915 s, 2855 m, 2080 s, 1598 m, 1463
5 10
H -
2 4
N
3.53; Cu, 50.12; N, 22.05.
X-ray Structure Determinations
The crystals were mounted on glass fibers, and measurements
were made at 24 ( 2 °C. Data for 2-7 were collected on an
Enraf-Nonius CAD-4 diffractometer with graphite-monochro-
mated Mo KR radiation (λ ) 0.710 73 Å). The intensities of
three representative reflections were measured after every 50-
-
1
w, 1370 w, 1250 w, 1095 m, 1053 s, 955 m, 532 w, 455 w cm
Anal. Calcd for C : C, 26.96; H, 4.53; Cu, 47.55; N, 20.96.
Found: C, 26.91; H, 4.65; Cu, 48.83; N, 20.71.
Preparation of (CuCN) (tetmen) (7). A blue color developed when
.
6 2 4
H12Cu N
6
3
N,N,N′,N′-tetramethylethylenediamine (174 mg, 1 mmol) was dissolved
in 30 mL of the “standard solution”. When heated to 95 °C, the solution
became colorless. After the hot solution was filtered, it was placed in
a 95 °C water bath that was allowed to cool to 80 °C over a 90 min
period. At that point (crystal formation was evident), the water bath
was placed on an insulated surface and allowed to cool to room
temperature. The next day the crystals (predominantly colorless, but
with a scattering of pale-blue green present, 99 mg, 33%) were collected
by filtration: IR 3420 br, m, 2975 w, 2950 w, 2865 m, 2830 m, 2790
w, 2107 s, 2060 m, 1628 br, w, 1458 s, 1350 w, 1283 m, 1245 w,
8
0 min of X-ray exposure time; in each of the seven data sets
these intensities remained constant throughout data collection,
indicating crystal and electronic stability (no decay corrections
were applied). Data for 8 were collected on a Siemens SMART
system using the same radiation. Again no decay corrections
were necessary. Crystallographic data for 2-8 are presented in
Table 1. The structures were solved by direct methods using
6
7
the programs MITHRIL and DIRDIF. The neutral atom
scattering factors used include correction for the real and
8
1
7
183 w, 1158 w, 1127 w, 1098 w, 1043 w, 1030 m, 1007 w, 950 m,
imaginary components of the effect of anomalous dispersion.
All calculations were performed using the TEXSAN crystal-
97 m, 768 w, 580 br, w, 480 br, w cm- . Anal. Calcd for C24
12: C, 32.54; H, 5.46; Cu, 43.03; N, 18.97. Found: C, 32.36; H,
.60; Cu, 45.57; N, 18.72.
1
48
H -
9
6
Cu N
lographic software package. The non-hydrogen atoms were
refined anisotropically except for the cyanide atoms in 7, which
is discussed later. There is a tendency for the bridging CN
groups to have end-for-end disorder in these compounds. In 3
and 4, the space group symmetry required this disorder to be
complete. In the remaining compounds, each such group was
refined with the degree of disorder as a variable. The atoms in
all the bridging groups are labeled C1N, etc., as a reminder of
the possible disorder. Except for H11 in 8, which was refined
with isotropic displacement parameters, H atoms were included
in the structure factor calculations in idealized positions and
were assigned isotropic displacement parameters that were 20%
greater than the Beq value of the atom to which they were
bonded.
5
Preparation of (CuCN)(phpip) (8). N-Phenylpiperazine (81 mg,
.5 mmol) was added to 30 mL of the “standard solution”. Stirring
0
with a magnetic mixer produced a very pale yellow solution with a
small amount of a white precipitate. By warming to 85 °C on the steam
bath, nearly all of the precipitate dissolved. After the hot solution was
filtered, the flask was stoppered and placed on an insulated surface.
Within a few hours nearly colorless crystals were visible. The next
day the product (large needles, 176 mg, 65%) was collected by
filtration: IR 3420 br, m, 3205 m, 3045 w, 3025 w, 2965 w, 2940 w,
915 w, 2805 m, 2108 m, 2060 s, 1592 s, 1585 w, 1483 s, 1440 s,
377 m, 1324 doublet m, 1285 w, 1250 m, 1222 s, 1187 m, 1145 m,
105 m, 1075 w, 1030 w, 1018 m, 983 m, 908 s, 885 w, 850 m, 750
2
1
1
s, 690 s, 635 w, 520 m, 415 br, w, 515 br, w. Anal. Calcd for C11
CuN : C, 52.68; H, 5.22; Cu, 25.34; N, 16.75. Found: C, 51.79, 52.48;
H, 5.60, 5.57; Cu, 25.90, 27.12; N, 16.52, 16.56.
Preparation of (CuCN) (propda) (9). The addition of 1,3-pro-
13
H -
3
Cu2(CN)3(dabco-H) (2) occurs in a chiral space group. Both
enantiomers were refined, and the enantiomer with the lower R
value is reported. The opposite enantiomer refined with R )
2
panediamine (74 mg, 1 mmol) to the “standard solution” produced an
immediate purple-blue solution. While the solution was heated on the
steam bath, the color lightened briefly and then became dark blue with
a tinge of purple. After the temperature reached 85 °C, the solution
was filtered to remove a small amount of mauve precipitate. The flask
was placed in a 70 °C water bath that was allowed to cool slowly to
room temperature. The following day the product (red-wine rhomboid
microcrystals, 49 mg, 19%) was collected by filtration: IR 3420 br,
m, 3285 s, 3235 m, 2920 w, 2880 w, 2095 s, 1583 s, 1467 w, 1430 w,
(6) MITHRIL: Gilmore, C. J. J. Appl. Crystallogr. 1984 17, 42.
(7) DIRDIF: Beurskens, P. T. Technical Report 1984/1 Crystallography
Laboratory, Toernooiveld, 6525 Ed Nijmegen, Netherlands.
(
8) (a) Cromer, D. T.; Waber, J. T. International Tables for X-ray
Crystallography; The Kynoch Press: Birmingham, England, 1974;
Vol. IV, Table 2.2A. (b) Cromer, D. T. Ibid. Table 2.3.1.
9) TEXSAN-TEXRAY Structure Analysis Package, Molecular Structure
Corp., 1985.
(

Complexes Produced by Reaction of CuCN with Diamines
.032, Rw ) 0.043. The CN groups, which might have been
Inorganic Chemistry, Vol. 38, No. 5, 1999 987
Table 2. Selected Bond Distances (Å) and Angles (deg)
0
ordered, appear to be completely disordered within experimental
error.
bond distances
bond angles
Cu (CN) (dabco-H) (2)
2 3
(
CuCN)2(dmpip) (3) and (CuCN)2(pip) (4) were straightfor-
ward.
Cu2(CN)3(pip-H) (5) has an arrangement similar to that of
2), and again the CN groups might have been ordered but
appear to be disordered within experimental error.
Cu1-C1N
Cu2-N2C
Cu2-N11
1.957(4)
1.984(4)
2.238(6)
N2C-Cu2-N11
N2C-Cu2-N2C′
C1N-Cu1-C1N′
102.1(2)
115.7(1)
119.9(2)
(
(
CuCN)
2
(dmpip) (3)
Cu1-N1C
Cu1-N11
1.878(3)
2.244(3)
N1C-Cu1-N1C′
N1C-Cu1-N11
156.7(2)
101.4(1)
(CuCN)2(butda) (6) was straightforward.
(CuCN)2(tetmen) (7) occurred as colorless and pale blue green
2
(CuCN) (pip) (4),
crystals. Both kinds of crystals had identical unit cell dimensions
and were presumed to be the same. The crystals are acentric,
which leads to a lower value for the ratio of the number of
observations to the number of parameters. There are 1567
observed reflections plus another 1416 Friedel opposites, which
cannot be regarded as independent with respect to refining
positional and displacement parameters. These were not enough
data to allow all the atoms to be refined as anisotropic. It was
decided to refine the CN atoms isotropically, despite their
possible disorder, as soon as it became apparent that the tetmen
atoms were even more disordered. Five-membered metal-
ethylenediamine rings are usually slightly puckered. In this
structure, where the rings lie across a mirror plane, this
puckering leads to disorder, which shows up as very anisotropic
displacement ellipsoids. The presence of the disorder leads to
a lowering of the diffraction intensities and contributes to the
shortage of data. The CN atoms were treated as possibly
disordered, but the uncertainties in the occupancies are large,
and nothing certain can be said about the degree of order or
disorder. Since this structure is in a polar space group,
refinement was carried out in both polarities. The two refine-
ments converged to identical R and Rw values, and the one
reported was chosen arbitrarily. It is possible that the crystal
was actually a racemic twin.
Cu1-Cu1′
Cu1-N1C
Cu1-N1C′
Cu1-N2C
Cu1-N11
2.581(1)
2.011(3)
2.221(3)
1.933(3)
2.107(2)
N1C-Cu1-N1C′
N1C-Cu1-N2C
N1C-Cu1-N11
N1C′-Cu1-N2C
N1C′-Cu1-N11
N2C-Cu1-N11
105.0(1)
116.8(1)
112.9(1)
114.7(1)
92.4(1)
112.3(1)
Cu
2
(CN)
3
(pip-H) (5)
Cu1-C1N
Cu1-C3N′
Cu1-N5C′
Cu2-N2C
Cu2-N4C
Cu2-C6N
Cu2-N11
1.941(5)
1.909(5)
1.918(5)
1.956(5)
2.012(4)
1.952(5)
2.153(3)
C3N′-Cu1-N5C′
C1N-Cu1-N5C
C1N-Cu1-C3N′
N4C-Cu2-C6N
N2C-Cu2-C6N
N2C-Cu2-N4C
N2C-Cu2-N11
N4C-Cu2-N11
C6N-Cu2-N11
125.5(2)
115.7(2)
117.4(2)
110.9(2)
122.2(2)
109.5(2)
106.2(2)
101.7(1)
104.0(1)
(CuCN)
2.672(1)
1.969(2)
1.890(3)
2.060(2)
2
(butda) (6)
Cu1-Cu1′
Cu1-N1C
Cu1-C2N′
Cu1-N11
N1C-Cu1-C2N′
N1C-Cu1-N11
C2N-Cu1-N11
123.3(1)
105.5(1)
124.1(1)
(CuCN)
2
(tetmen) (7)
Cu1-C1N′
Cu1-N2C
Cu1-N4C
Cu2-Cu3
Cu2-C3N
Cu2-C5N
Cu2-N21
Cu3-C3N
Cu3-C5N
Cu3-N31
1.90(2)
1.98(2)
1.95(1)
2.307(2)
2.15(2)
1.97(2)
2.08(1)
2.02(2)
2.16(2)
2.09(1)
N2C-Cu1-N4C
C1N′-Cu1-N4C
C1N′-Cu1-N2C
N21-Cu2-N21′
C5N-Cu2-N21
C3N-Cu2-N21
C3N-Cu2-C5N
C5N-Cu3-N31
C3N-Cu3-N31
C3N-Cu3-C5N
N31-Cu3-N31′
C8N-Cu4-N10C
N6C-Cu4-N10C
N6C-Cu4-C8N
C9N′-Cu5-N11C
N7C-Cu5-N11C
N7C-Cu5-C9N′
N61-Cu6-N61′
C12N-Cu6-N61
103.8(6)
127.4(6)
128.8(6)
88.5(5)
115.9(4)
110.0(4)
113.8(7)
111.4(4)
117.1(4)
111.3(7)
86.5(5)
126.3(5)
106.2(6)
127.5(6)
115.5(7)
114.5(7)
130.0(5)
86.6(5)
In (CuCN)(phpip) (8) the CN group might be expected to be
completely disordered, but it appears to be partially ordered with
occupancy 0.81(2) for the major component.
Selected bond angles and bond distances for 2-8 are provided
in Table 2. The bond distances are in the normal range. The
bond angles around the Cu show large distortions from 120°
for the three-coordinate Cu and from 109.5° for the four-
coordinate Cu, but the distortions are no larger than those found
in other Cu(I) structures. The most interesting localized structural
features are the Cu2(CN)2 fragments found in several of the
structures. These are discussed at the end of the Solid State
Structures section of the Discussion. The anisotropic displace-
ment ellipsoids for the seven structures are available in the
Supporting Information. The packing is shown in Figures 1-8.
Cu4-N6C
Cu4-C8N
Cu4-N10C
Cu5-N7C
Cu5-C9N′
Cu5-N11C
Cu6-C12N
Cu6-N61
1.99(1)
1.84(2)
1.97(1)
1.93(2)
1.85(2)
1.93(1)
1.84(1)
2.06(1)
136.7(3)
(CuCN)(phpip) (8)
2.534(1)
1.946(2)
2.013(3)
2.148(2)
0.84(2)
Cu1-Cu1′
Cu1-N1C
Cu1-C2N′
Cu1-N11
N11-H11
H11‚‚‚N14′
N11‚‚‚N14′
C2N′-Cu1-N11
N1C-Cu1-N11
N1C-Cu1-C2N′
N11-H11‚‚‚N14′
104.6(1)
116.1(1)
121.8(1)
166.2(7)
Discussion
2.55(3)
3.271(3)
Solid-State Structures. There is more variety than similarity
in the seven structures reported here. The CN groups are
involved in bridging in every case, but even here the usual Cu-
CN-Cu bridge is replaced by a Cu2-CN-Cu2 arrangement
for one of the CN groups in 4 and by Cu2-CN-Cu bridges in
In Cu2(CN)3(dabco-H) (2) (see Figure 1), there are hexagonal
sheets, [Cu2(CN)3]n, similar to those found in KCu2(CN)3‚H2O.
The difference is that in KCu2(CN)3‚H2O the large hexagonal
holes were filled by potassium ions and water molecules that
were not covalently bonded to the sheets, whereas in our
10
6
-8. In the complexes with dabco-H (2) and pip-H (5), one of
the amine nitrogens is protonated. In the complex with phpip
8) the nitrogen bearing the phenyl group is active as a H-bond
(
+
compound there is a dabco-H group bonded to alternate Cu
acceptor to the hydrogen atom on the other nitrogen in an
adjacent piperazine. In every other case the amine nitrogens
are bonded to copper. In the complexes with dmpip (3), pip
atoms making the entire two-dimensional sheet neutral. These
dabco-H groups all point in the same direction, both in a single
sheet and in adjacent sheets, the groups from one sheet filling
the holes in the next sheet. The H atom on N14 points directly
+
(4), and butda (6) the diamine forms an ambidentate bridge; in
the complex with tetmen (7) the diamine chelates with the
copper.
(10) Cromer, D. T.; Larson, A. C. Acta Crystallogr. 1962, 15, 397.

988 Inorganic Chemistry, Vol. 38, No. 5, 1999
Stocker et al.
Figure 3. View perpendicular to the (001) plane of a two-dimensional
sheet out of the extended structure of (CuCN)
three-dimensional structure is completed with Cu
2
(pip) (4). The overall
-CN-Cu -CN
2
2
chains parallel to the c axis. CN-Cu -CN fragments from these chains
2
are shown. The next layer above or below is related to the one shown
by a c glide. H atoms are omitted for clarity.
2 3
Figure 1. Extended structure of Cu (CN) (dabco-H) (2). The view is
along the c axis. In this and the following figures showing extended
structures the Cu atoms have been shown larger than the rest. H atoms
have been omitted for clarity.
2 3
Figure 4. Extended structure of Cu (CN) (pip-H) (5). View normal
to the (10 1h ) plane. H atoms are omitted for clarity.
2
Figure 2. Extended structure of (CuCN) (dmpip) (3). The view is
normal to the (20 1h ) plane. H atoms have been omitted for clarity. The
bonds from the piperazine ring to the Cu atoms are in axial positions,
leading to a highly puckered two-dimensional sheet.
of group will be discussed at greater length after the discussion
of 8. This structure can be thought of as Cu-Cu-CN-Cu-
Cu chains held together by bridging pip molecules in a fashion
similar to that in 3 to form two-dimensional sheets. These sheets
are then held together by Cu2-CN-Cu2 bridges to the layer
above. The Cu-Cu-CN-Cu-Cu chains in alternate layers are
more or less orthogonal to each other.
at the Cu2 atom two layers away (that is, N-H‚‚‚Cu) with a
surprisingly short N‚‚‚Cu distance of 3.296(4) Å.
In (CuCN)2(dmpip) (3) (see Figure 2), there are two-
dimensional sheets. Cu-CN-Cu-CN chains are held together
by bridging dmpip molecules. Somewhat similar arrangements
occur in (CuCN)2‚etu (etu ) 2-imidazolidinethione or N,N′-
Cu2(CN)3(pip-H) (5) (see Figure 4) has an arrangement that
is similar to that in Cu2(CN)3(dabco-H) (2). Hexagonal sheets,
1
1
ethylenethiourea) and (CuCN)2‚detu‚H2O (detu ) 1,3-di-
-
+
methyl-2-thiourea),12 although in both cases the arrangement
Cu2(CN)3 , are neutralized by pip-H ions bonded to alternate
Cu atoms. In this structure, however, alternate layers point in
of the bridging groups between chains is different from that in
+
opposite directions, and the pip-H from one layer fill the
(
CuCN)2(dmpip).
CuCN)2(pip) (4) (see Figure 3) has a three-dimensional
network. This structure contains Cu2(CN)2 fragments. This type
hexagonal holes in the adjacent layer; this leads to a centric
structure in this case. As was the case in 2 the H atom on N14
points directly at the Cu2 atom in an adjacent layer with another
short N‚‚‚Cu distance, 3.304(4) Å; in this case the arrangement
is not required to be linear but the N-H‚‚‚Cu angle is found to
be 176°.
(
(
11) Stocker, F. B.; Troester, M. A.; Britton, D. Inorg. Chem. 1996, 35, 5,
145.
12) See ref 11.
3
(

Complexes Produced by Reaction of CuCN with Diamines
Inorganic Chemistry, Vol. 38, No. 5, 1999 989
Figure 5. Extended structure of one two-dimensional sheet of (CuCN)
butda) (6). View normal to the (100) plane. These sheets are highly
puckered (see Figure 6). H atoms are omitted for clarity.
2
-
2
Figure 7. Extended structure of (CuCN) (tetmen) (7). View along the
(
a axis. This is a two-dimensional ribbon, with a width roughly equal
to b, repeating along c. Except for the tetmen ligands, the ribbon is
planar, lying in a mirror plane, and again only half of each tetmen
molecule can be seen.
atoms are the basis of the central chain while Cu4 and Cu5 are
the basis of the outer chains. The central and outer chains are
connected by Cu2(CN)2 groups similar to those found in 4 and
6. The Cu in these bridges, Cu2 and Cu3, have their coordination
completed by being part of a chelate ring with the tetmen. The
last Cu, Cu6, is also part of such a chelate ring, and is attached,
through a cyanide bridge to the outer chain. One can imagine
two simpler arrangements. The first is a one-dimensional Cu-
CN-Cu-CN chain similar to the outer chain with groups
similar to the CN-Cu-tetmen groups attached at every Cu in
the chain; there would be only two kinds of Cu in the
arrangement. The second is a two-dimensional sheet where the
motif between the two outer chains is continued indefinitely in
both directions; there would only be two kinds of Cu atom in
this arrangement. Presumably the observed form has a lower
free energy than either of the two simpler, hypothetical phases.
It is not obvious why this should be so.
2
Figure 6. Stereoview of (CuCN) (butda) (6) from the same direction
as Figure 5, showing the interweaving of three of the two-dimensional
sheets.
(
CuCN)(phpip) (8) (see Figure 8) forms chains Cu-CN-
(
CuCN)2(butda) (6) (see Figures 5 and 6) contains two-
Cu-CN with phpip groups attached to each Cu atom. This is
an arrangement that is well-known, occurring in the Cu(CN)2
dimensional networks similar to those in 3 as can be seen in
Figure 5. These networks have an hexagonal connectivity with
large empty spaces in the centers of the hexagons. To fill space
efficiently, three of these hexagonal networks interweave with
successive networks related by translation along the b direction.
A similar sort of interweaving occurs in the structure of AgC-
-
1
4
15
polymer in KCu(CN)2 and NaCu(CN)2‚H2O, as well as in
16
17
CuCN‚DMSO, CuCN‚Et2NH and CuCN‚Et3N, CuCN‚ta (ta
18
)
)
thioacetamide), and in both polymorphs of CuCN‚tmtu (tmtu
1
9
tetramethylthiourea). The unique feature of this compound
CN)3,13 except that the interweaving only involves two layers
is that the H11 atom on N11 forms a hydrogen bond to an N14
atom from an adjacent chain (N11‚‚‚N14, 3.371(5) Å; N11-
H11‚‚‚N14, 166(1)°; arrangement at N14, close to tetrahedral).
These hydrogen bonds bind the chains into two-dimensional
sheets. The N11‚‚‚N14 distance is at the high end of the range
for N-H‚‚‚N hydrogen bonds, but each piperazine is involved
in two such bonds, once as a donor and once as an acceptor
and the H-bond lengths are not independent of the repeat
(
rather than three. These triply interwoven networks form thick
layers in which the faces of the layers are the Cu-CN-Cu-
CN chains. Short Cu-Cu distances are found between layers
as part of Cu2(CN)2 fragments similar to those found in 4. These
are discussed after the discussion of structure 8.
(
CuCN)2(tetmen) (7) (see Figure 7) forms a ribbon that
translates in the c direction. As one traverses the ribbon from
side to side, in as direct a manner a possible, 12 Cu atoms are
passed in the traverse. The two halves of the ribbon are related
by a c glide relation so that six Cu atoms occur in the
asymmetric unit. The ribbon can be thought of as three Cu-
CN-Cu-CN chains parallel to the ribbon direction. The Cu1
(
(
14) Cromer, J. D. J. Phys. Chem. 1957, 61, 1388.
15) Kappenstein, C.; Hugel, R. P. Inorg. Chem. 1977, 16, 250.
(16) Emokpae, T. A.; Ukwueze, A. C.; Walton, D. R.; Hitchcock, P. B.
Synth. React. Inorg. Met.-Org. Chem. 1986, 16, 387.
(
17) Dyason, J. C.; Healy, P. C.; Engelhardt, L. M.; Pakawatchai, C.;
Patrick, V. A.; White, A. H. J. Chem. Soc., Dalton Trans. 1985, 839.
18) Stocker, F. B.; Troester, M. A. Inorg. Chem. 1996, 35, 3154.
(
(13) Konnert, J.; Britton, D. Inorg. Chem. 1966, 5, 1193.
(19) See ref 11.

990 Inorganic Chemistry, Vol. 38, No. 5, 1999
Stocker et al.
distance. It can be seen the changes described above occur, but
not with complete regularity. The limit of a symmetric arrange-
ment with both Cu-C distances the same is most nearly reached
in CuCN‚NH3. In the limit of the symmetric arrangement, we
would regard the bonding as two three-center Cu-C-Cu bonds,
reminiscent of the bonding in diborane.
The infrared stretch frequencies for the cyanide groups in
-
1
2
-8 appeared in the normal range, from 2040 to 2195 cm .
-n+1
In simple aqueous complexes of Cu(CN)n
(where n ) 2-4)
the stretch frequency of the cyanide group decreases with
2
2
increasing coordination of the copper atom. Three-coordinate
copper sites predominate in the new complexes, appearing as
Cu(CN)3, Cu(CN)2L, or Cu(CN)(>L). Complexes 2 and 5 show
four-coordinate copper sites as Cu(CN)3L. No relationship
between coordination number and frequency was evident in
these compounds.
Synthesis. Piperazine, N-phenylpiperazine, and 1,4-dimeth-
ylpiperazine were not the only members of the piperazine family
to form complexes with CuCN. Both 2-methyl- and N-
methylpiperazine gave amorphous solids that were shown by
their IR spectra to contain cyanide and ligand. The presence of
copper was established by means of a simple test tube
experiment. After a number of synthesis efforts failed to produce
these solids in crystalline form, they were not examined further.
Our investigation of the complexing ability of aromatic
diamines with CuCN was limited to reaction attempts with o-,
m-, and p-phenylenediamine. In each of these cases, a decom-
position outcome was indicated by the formation of black
amorphous residues.
Figure 8. Extended structure of (CuCN)(phpip) (8). View normal to
the (100) plane. The N atoms are shown slightly larger than the C
atoms. H atoms have been omitted for clarity, except for H11. One-
dimensional chains occur parallel to the c axis. Adjacent chains are
held together by hydrogen bonds. The H11 atom from one chain can
be seen pointing toward an N14 atom from an adjacent chain.
2 2
Table 3. Cu (CN) Group Geometry
Variable results were obtained in the study of the reactivity
of CuCN toward the straight-chain diamines, H2N(CH2)nNH2,
2
3
where n ) 2-6. In 1966, Cooper and Plane treated CuCN
with aqueous ethylenediamine (en), producing a mixed valence
purple copper complex, Cu(II)Cu(I)2(CN)4(en)2(H2O). Our
synthetic method, although differing substantially from theirs,
produced the same complex. This was established by comparing
the IR spectrum of our product with the published spectrum of
Cooper and Plane’s product. Cromer and co-workers24 deter-
mined its crystal structure in 1972. We did produce the novel
complex 7 from CuCN and the en derivative, N,N,N′,N′-
tetramethylethylenediamine. The reaction of 1,3-propanediamine
with CuCN produced (CuCN)2(propda) 9, a red-violet micro-
crystalline complex. Although a number of synthesis variations
of 9 were attempted, we were unable to produce crystals large
enough for X-ray determination. Complexation of 1,4-butane-
diamine with CuCN proceeded smoothly, giving an excellent
yield of the crystalline complex 6. Reaction attempts with 1,5-
pentanediamine and 1,6-hexanediamine with CuCN/S2O32
produced only traces of amorphous precipitates. These materials
were not considered pure enough to warrant further examination.
General Methods. The original intent behind this work was
to show that the synthetic method was more generally usefuls
that the thioureas previously used as ligands or bridges could
be replaced by amines. To this end, the amines were chosen to
represent a variety of types. The results were generally satisfac-
tory in regard to the syntheses, although it should be noted that
there are still synthetic questions. In particular, the compositions
of the various products do not follow, in any easily understood
way, from the compositions of the original reaction mixtures.
Cu-Cu
Å)
Cu-C
Cu‚‚‚C
Cu-C-N
(
(Å)
(Å)
(deg)
compound
ref
2.307
2.307
2.417
2.534
2.581
2.636
2.672
1.967
2.016
2.090
2.013
2.011
1.931
1.890
2.151
2.164
2.129
2.347
2.221
2.418
2.571
155.8
155.8
146.7
160.7
151.2
158.9
174.5
7
7
this
this
20
this
this
21
CuCN‚NH
3
8
4
3 2
[CuCN] ‚H O
6
this
distance along the chain, which is largely fixed by the Cu-CN
bonding. The Cu and CN groups from adjacent chains lie in
planes, as can be seen in Figure 8. The packing is such that
pairs of these planes are parallel to each other and near to each
other so that there are short Cu-Cu distances as part of Cu2-
CN)2 groups, as was the case also in 4, 6, and 7.
In 4 and 6-8 above, Cu2(CN)2 groups were found as part of
the structures. These groups can be thought of as forming by
the sideways approach of two antiparallel CuCN groups
involving three-valent Cu in the original group. (See the drawing
in Table 3.) At the start, before the groups approach each other,
each group contains a trigonal Cu atom, approximately coplanar
with its three ligands, and a CN group with a linear Cu-CN
geometry. As the groups approach, the CN bends away from
the incoming Cu, and the original Cu-C bond lengthens as a
new, additional Cu‚‚‚C bond is forming. In Table 3, data are
tabulated for the four such groups found in this study, along
(
-
20
with those from similar groups in CuCN‚NH3 and [CuCN]3‚
H2O.21 Table 3 is ordered from shortest to longest Cu-Cu
(
22) Nakamoto, K. Infrared and Raman Spectra of Inorganic and Coor-
dination Compounds, 4th ed.; John Wiley & Sons: New York, 1986;
pp 273-276
(
20) Cromer. D. T.; Larson. A. C.; Roof, R. B., Jr. Acta Crystallogr. 1965,
9, 192.
21) Kildea, J. D.; Skelton. B. W.; White, A. H. Aust. J. Chem. 1985, 38,
329.
1
(23) Cooper, D.; Plane, R. A. Inorg. Chem. 1966, 5, 1677.
(24) Williams, R. J.; Larson, A. C.; Cromer, D. T. Acta Crystallogr. 1972,
C46, 858.
(
1

Complexes Produced by Reaction of CuCN with Diamines
Inorganic Chemistry, Vol. 38, No. 5, 1999 991
The structural results, although they were not the primary
goal, are of interest in their own right. The cyanide or nitrile
group is a popular one for the construction of solid-state
structures as the following recent examples show. Iwamoto and
co-workers have used Ni(CN)4 as a bridging group to form
a large series of clathrate complexes [Cd(diamine)2Ni(CN)4]‚
chains with the ligands involved in various ways. Sometimes,
one-dimensional chains form with the ligands attached as side
groups or two or three of the one-dimensional chains are cross-
linked to form ribbons that are still one-dimensional polymers.
Other times, the ligands, or additional cyanides, cross-connect
the CuCN chains completely to form two-dimensional polymers.
Finally, the CuCN chains can be cross-linked in two directions
to give a three-dimensional polymer. The wide range of
structural types means that copper cyanide/ligand complexes
have possibilities for the design of solid-state materials with
particular types of structures. Again, it should be noted that the
particular structure formed is not readily predictable from the
ligand used. A number of these complexes have been prepared
since the original work of Cromer and co-workers31 but there
has been, as yet, no systematic exploration of the structural
possibilities.
2
5
2-
2
6
3-
xguest. Fischer and co-workers have shown that Co(CN)6
and Fe(CN)63 anions bridge Sn(CH3)3 and Pb(CH3)3 cations
-
+
+
-
27
in much the same fashion that CN anions do, except that the
greater complexity of the M(CN)63 ions leads to three-
dimensional polymers. Robson and co-workers28 have developed
variations on the Zn and Cd cyanide structures that lead to three-
dimensional structures with variable properties, including one
structure where C(C6H4CN)4 (plus appropriate ions to correct
-
2-
the charges) has replaced Zn(CN)4 as a four-coordinate
29
ambidentate group. They have also shown that replacement
-
-
of CN in Zn(CN)2 by C(CN)3 to form Zn[C(CN)3]2 replaces
the three-dimensional polymer of the cyanide (with four-
coordinate Zn) with a three-dimensional polymer with six-
coordinate Zn. Mao and Mayr30 have used p-cyanoisocyanoben-
zene as a bridging group between metal ions to form one-, two-,
and three-dimensional solid-state polymers.
Acknowledgment. We are indebted to Professor Wayne C.
Wolsey of Macalester College for encouragement and helpful
discussions and to Victor G. Young, Jr., of the X-ray Crystal-
lographic Laboratory of the University of Minnesota for
determining the structure of 8. Financial support from the
Howard Hughes Medical Institute is gratefully acknowledged.
The structures reported here and previously show that copper
cyanide/ligand complexes usually form polymeric (CuCN)n
Supporting Information Available: Figures showing the aniso-
tropic displacement ellipsoids of 2-8 and X-ray crystallographic files
for the structures of 2-8. This material is available free of charge via
the Internet at http://pubs.acs.org.
(25) Yuge, H.; Noda, Y.; Iwamoto, T. Inorg. Chem. 1996, 35, 1842 and
references therein.
(
26) Behrins, U.; Brimah, A. K.; Solman, T. M.; Fischer, R. D.; Apperly,
D. C.; Davies, N. A.; Harris, R. K. Organometallics 1992, 11, 1718.
27) Schlemper, E. O.; Britton, D. Inorg. Chem. 1966, 5, 507.
28) Hoskins, B. F.; Robson, R. J. J. Am. Chem. Soc. 1990, 112, 1546.
29) Batten, S. R.; Hoskins, B. F.; Robson, R. J. J. Chem. Soc., Chem.
Commun. 1991, 445.
IC970226B
(
(
(
(31) The first structure reported: Cromer, D. T. J. Phys. Chem. 1957, 61,
1388. For later work, see: Cromer, D. T.; Larson, A. C. Acta
Crystallogr. 1972, B28, 1052 and references therein.
(30) Mao, L.-F.; Mayr, A. Inorg. Chem. 1996, 35, 3183.