Syntheses and solid-state structures of molecular and extended silver(I) complexes, of 4-isocyano-3,5-diisopropylbenzonitrile

Article abstract of DOI:10.1006/jssc.2000.8689

The molecular complexes [Ag(4-CN-3,5-i-Pr₂-C₆H₂CN)₂]X, 1 (a, X= BF₄; b, X= SO₃CF₃), have been prepared by reaction of the respective silver(I) salts with 2 equivalents of the iso

Full text of DOI:10.1006/jssc.2000.8689

KANNAN BALA VVC
DISC USED NO !
JSSC*8689
DATE 4...*....4...*....2..0...0..0.........
Journal of Solid State Chemistry 152, 247}252 (2000)
doi:10.1006/jssc.2000.8689, available online at http://www.idealibrary.com on
Syntheses and Solid-State Structures of Molecular and Extended
Silver(I) Complexes of 4-Isocyano-3,5-diisopropylbenzonitrile
Ming-Xing Li,*ꢂꢀ Kung-Kai Cheung,*ꢂꢁ and Andreas Mayr-ꢂꢁ
*Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People+s Republic of China; and
-Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York, 11794-3400
DEDICATED TO PROF. W. P. FEHLHAMMER ON THE OCCASION OF HIS 60TH BIRTHDAY
and polytopic ligand, it is possible to exert considerable
control over the electronic and steric properties (2). As far as
The molecular complexes [Ag(4-CN-3,5-i-Pr2-C6H2CN)2]X,
1 (a, X ؍ BF4; b, X ؍ SO3CF3), have been prepared by reaction
the dimensionality and the dimensions of the solid-state
of the respective silver(I) salts with 2 equivalents of the isocyan-
structures are concerned, the primary steric information is
ide in benzene solution. Reaction of 1b with an equivalent amount
usually contained in the polytopic organic ligands (3). As an
of AgSO3CF3 in benzene solution gave the extended molecular
alternative approach toward the design of one-, two-, and
solid +[Ag(4-CN-3,5-i-Pr2-C6H2CN)2]SO3CF3,n, 2. The solid-
state structures of 1a and 2 have been determined by single-
crystal X-ray crystallography. Compound 1a crystallizes in the
triclinic space group P1 with a ؍ 10.506(2) A, b ؍ 12.838(2) A,
three-dimensional coordination polymers, we (4) are utiliz-
ing linear functionalized isocyanide ligands (5) and the in-
trinsic coordination geometries of various transition metal
c ؍ 12.974(2) A, a ؍ 100.65(2)3, b ؍ 101.52(2)3, c ؍ 105.37(2)3, isocyanide complexes (6). Because of the propensity of sil-
V ؍ 1600.1(7) A3, and Z ؍ 2 with R ؍ 0.056 and wR ؍ 0.087.
ver(I) to form linear dicoordinate metal complexes and the
Compound 2 crystallizes in the triclinic space group P1 with
a؍9.6868(8) A, b؍10.551(1) A, c؍11.559(1) A, a؍76.350(9)3,
b ؍ 82.037(9)3, c ؍ 71.481(9)3, V ؍ 1086.0(4) A3, and Z ؍ 1 with
R ؍ 0.027 and wR ؍ 0.036. Compound 1a may be described as
a dicoordinate silver(I) complex with a signi5cantly bent linear
coordination geometry (C+Ag+C 156.1(2)3). The bending of the
diisocyanide metal group is caused by the interaction with the
BF4 anion (shortest Ag+F distance 2.534(8) A). The nitrile
groups in 1b are not engaged in any directional intermolecular
interaction. The solid-state structure of 2 consists of linear chains
kinetic lability of many silver(I)}ligand interactions, it ap-
peared promising to attempt the synthesis of crystalline
low-dimensional solids from functionalized isocyanide sil-
ver(I) complexes. Silver(I) salts have previously been demon-
strated to form coordination polymers based on
bis(isocyanide)- (7) as well as bis(nitrile)silver units (8).
Therefore, it appeared to be of interest to explore the coord-
ination chemistry of cyanoisocyanoarenes and silver(I) salts.
Here we report the formation of discrete bis(isocyanide)
of [Ag(4-CN-3,5-i-Pr2-C6H2CN)2]SO3CF3 units, whereby each complexes and a one-dimensional coordination polymer
silver ion is coordinated to one isocyano group and one nitrile
group of consecutive cyanoisocyanoarene ligands. These linear
chains are arranged in antiparallel fashion to form in5nite sheets.
Within the sheets, the silver ions of pairs of chains are pulled near
each other by electrostatic interactions with the SO3CF3 anions.
These double chains are held together primarily by p interactions
of the cyanoisocyanoarene groups. ( 2000 Academic Press
from 4-isocyano-3,5-diisopropylbenzonitrile and Ag(I) salts
(see Scheme 1).
EXPERIMENTAL
3,5-Diisopropyl-4-isocyanobenzonitrile was prepared as
described in the literature (9). Benzene, tetrahydrofuran,
ether, and CH Cl were distilled under N from appropriate
Key Words: silver(I); isocyanobenzonitrile; metal complex;
one-dimensional coordination polymer.
ꢁ
ꢁ
ꢁ
drying agents. All other solvents and reagents were used as
received from commercial sources. All synthetic procedures
INTRODUCTION
were performed under an atmosphere of N . The ꢀH NMR
spectra were recorded at 300 MHz.
Coordination polymers (1) are a promising class of solid-
state molecular material. By proper choice of metal center
ꢁ
ꢀPermanent address: Department of Chemistry, Fudan University,
Shanghai, People's Republic of China.
[Ag(4-CN-C6H2-3,5-(i-C3H7)2-CN)2](BF4) ) (C6H6)0.5, 1a
ꢁTo whom correspondence should be addressed. K.-K.C.: E-mail
kkcheung@hkucc.hku.hk. AM.: fax #1-516-632-7960; e-mail amayr@
notes.sc.sunysb.edu.
AgBF (48.7 mg, 0.25 mmol) is dissolved in 20 ml of dich-
ꢃ
loromethane. 4-CN-C H -3,5-(i-C H ) -CN (106.2 mg,
ꢄ ꢁ
ꢅ ꢆ ꢁ
247
0022-4596/00 $35.00
Copyright ( 2000 by Academic Press
All rights of reproduction in any form reserved.

JSSC=8689=TSK=VVC=BG
248
LI, CHEUNG, AND MAYR
monochromatized MoKa radiation (j"0.71073 A) and an
MAR X-ray generator (50 kV and 50 mA) using 33 ꢀ-oscil-
lation and a detector-to-crystal distance of 120 mm and
270 s exposure. Re#ections from 70 images were interpreted
and intensities integrated using the program DENZO (10).
From 16,173 measured re#ections, 5437 unique re#ections
were obtained (R "0.027), and the data were corrected for
*ꢂꢃ
Lorentz and polarization e!ects.
The di!raction data for complex 2 were collected on
a Rigaku AFC7R di!ractometer with MoKa radiation
(j"0.71073 A) and a rotating anode X-ray generator
(50 kV and 160 mA), u}2h scan mode, 4060 re#ections mea-
sured, 3834 unique (R "0.019), data corrected for Lorentz
*ꢂꢃ
and polarization e!ects, and an empirical absorption based
on azimuthal scans of "ve strong re#ections (minimum and
maximum transmission factors 0.973 and 1.000).
The structure determinations and numerical calculations
were done using the MSC crystal structure analysis package
TeXsan (11), using a Silicon Graphics computer, and the
full-matrix least-squares re"nements were on F using re#ec-
tions with I'3p(I).
SCHEME 1
0.5 mmol) is added. The solution is stirred for 12 hr. The
solution is reduced to about 5 ml and 20 ml of diethyl ether
is added to a!ord a white precipitate, which is "ltered o!
and washed with diethylther. Yield: 103 mg, 59%. This
product is dissolved in benzene. Upon slow evaporation,
colorless crystals form. ꢀH NMR (CDCl ): d 7.54 (s, 4 H),
ꢅ
7.37 (s, 3 H, benzene), 3.39 (h, 4 H), 1.34 (d, 24 H). IR (cm\ꢀ):
TABLE 1
CH Cl ; 2233(w), 2192(s); KBr, 3077 (w), 2968 (m), 2932 (w),
ꢁ
ꢁ
Crystal and Data Collection Parameters for Complexes 1a
and 2
2875 (w), 2232 (w), 2192 (m), 2160 (w), 1577 (w), 1465 (m),
1280 (w), 1077 (br, vs), 889 (w), 762 (w), 712 (m), 628 (w).
1a
2
[Ag(4-CN-C6H2-3,5-(i-C3H7)2-CN)2](SO3CF3), 1b
Formula
Formula weight
Crystal system
Space group
a, A
b, A
c, A
a, deg
b, deg
C
658.32
H
BN F Ag
C
H
N O F Ag
ꢅꢀ ꢅꢇ ꢃ ꢃ
ꢅꢄ ꢅꢈ
ꢃ
ꢄ ꢄ
ꢁ
1016.57
Triclinic
AgSO CF (128.5 mg, 0.5 mmol) is dissolved in 5 ml of
ꢅ
ꢅ
Triclinic
P1 (No. 2)
10.506(2)
12.838(2)
12.974(2)
100.65(2)
101.52(2)
105.37(2)
1600.1(7)
2
benzene. A benzene solution (5 ml) of 212 mg (1.0 mmol) of
P1 (No. 2)
9.6868(8)
10.551(1)
11.559(1)
76.350(9)
82.037(9)
71.481(9)
1086.0(4)
1
CN-C H (C H ) -CN is added with stirring. Within a few
ꢄ ꢁ ꢅ ꢆ ꢁ
minutes, a white precipitate forms. The mixture is stirred for
12 hr. The solid is "ltered o! and washed with diethyl ether.
Yield: 260 mg, 76%. IR (cm\ꢀ): CH Cl , 2237 (w), 2189 (s);
ꢁ
ꢁ
KBr, 3076 (w), 2968 (m), 2929 (w), 2873 (w), 2232 (w), 2200
(s), 2162 (w), 2123 (w), 1578 (w), 1460 (m), 1253 (br, s), 1154
(s), 1029 (s), 763 (w), 636 (s).
c, deg
<, Aꢅ
Z
¹, K
Crystal color
Crystal dimensions,
301
Colorless
301
Colorless
+[Ag(4-CN-C6H2-3,5-(i-C3H7)2-CN)](SO3CF3)],n, 2
[Ag(4-CN-C H -3,5-(i-C H ) -CN) ](SO CF ) (68.2mg, mm;mm;mm
0.25;0.20;0.10
0.25;0.10;0.10
ꢄ ꢁ
ꢅ ꢆ ꢁ
ꢁ
ꢅ
ꢅ
d(calcd), g cm\ꢅ
1.366
1.554
10.66
50
0.1 mmol) is dissolved in 20 ml of dichloromethane. A ben-
zene solution (10 ml) of AgSO CF (51.4 mg, 0.2 mmol) is
k, cm\ꢀ
6.77
ꢅ
ꢅ
2h max, deg
Unique re#ections
Re#ections (I'3p(I))
used in LS re"nement
No. of variables
R
added. The solution is stirred for 12 hr, and then allowed to
stand in an atmosphere of diethyl ether. Colorless crystals
form. The product is "ltered o! and washed with diethyl
ether. Yield: 15 mg, 32%. IR (KBr, cm\ꢀ): 3076 (w), 2968
(m), 2931 (w), 2876 (w), 2262 (w), 2187 (m), 1578 (w), 1468 (m),
1254 (br, s), 1166 (s), 1018 (s), 688 (m), 640 (s), 519 (m).
5437
3834
4412
357
0.056?
0.087@ꢂA
0.05
2551
253
0.027?
0.036@ꢂB
0.03
wR
(*/p)max
Goodness of "t
2.74
1.23
X-Ray Crystallographic Studies
*o, eA\ꢅ
!0.81/1.30
!1.10/1.24
The di!raction data for compound 1a were collected on
an MAR imaging plate detector system with graphite- pꢁ(F ). Apꢁ(F )"pꢁ(I)#(0.042F )ꢁ. B pꢁ(F )"pꢁ(I)#(0.030F )ꢁ.
ꢁ
ꢁ
?R"+#F "!"F #/+"F ". @R "[+w("F "!"F ")ꢁ/+wF ]ꢀꢉꢁ, w"4F /
ꢀ
#
ꢀ
ꢁ
ꢀ
#
ꢀ
ꢀ
ꢁ
ꢁ
ꢁ
ꢁ
ꢁ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ

JSSC=8689=TSK=VVC=BG
MOLECULAR COMPLEXES OF Ag(I) SALTS AND ISOCYANIDE
249
Hydrogen atoms at calculated positions with thermal and 1b. The appearance of two isocyanide stretching fre-
parameters equal to 1.3 times that of the attached C atoms quencies for 1a in the solid phase can be explained by the
were included in the calculations, but not re"ned. Crystal bending of the NC}Ag}CN group in the crystal structure
and data collection parameters for complexes 1a and 2 are (see below). The extended solid 2 was obtained by addition
summarized in Table 1.
of a benzene solution of AgSO CF to a methylene chloride
ꢅ
ꢅ
solution of 1b, and slow further addition of diethyl ether.
The expected outcome of this reaction was a one-dimen-
sional solid in which intact molecular units 1b are connected
by silver(I) ions via the nitrile groups. Coordination of the
RESULTS AND DISCUSSION
Synthesis and Characterization
The silver(I) bis-isocyanide complexes 1a and 1b have nitrile groups to Ag(I) in 2 is indicated by an increase of the
been prepared by adding 2 equivalents of 4-isocyano-3,5- nitrile N,C stretching frequency by 30 cm\ꢀ (KBr), and the
diisopropylbenzonitrile to AgBF and AgSO CF , respec- observed product is indeed a one-dimensional solid. How-
ꢃ
ꢅ
ꢅ
tively, in benzene solution. The isocyanide group is a signi"- ever, all isocyanobenzonitrile ligands within the individual
cantly stronger coordinating group than the nitrile group. extended chains are oriented in the same direction (see
As expected, only the formation of isocyanide metal com- below). Thus the identity of the molecular building blocks
plexes, not nitrile complexes, was observed. The coordina- 1b is lost in solid 2. The formation of 2 implies that the Ag}C
tion of the isocyanide group to the silver(I) center causes bonds in 1b are kinetically labile. In contrast to this situ-
a characteristic shift (about 75 cm\ꢀ) of the isocyanide ation, transition metal}isocyanide bonds are normally kin-
C,N IR stretching frequency of the free ligand (2115 cm\ꢀ etically stable, a fact which we have utilized toward the
in CH Cl ) to higher wavenumbers, while the stretching formation of geometrically well-de"ned building blocks for
ꢁ
ꢁ
frequency of the nitrile group (2233 cm\ꢀ) remains essen- coordination polymers (4, 9) and discrete open molecular
tially unchanged. In the solid phase (KBr), at least two IR structures (12). The kinetic lability of silver}isocyanide
absorptions are observed for the isocyanide groups of 1a bonds is also apparent from the formation of crystalline
FIG. 1. ORTEP drawing of the cation of compound 1a. The thermal ellipsoids are shown at the 40% probability level.

JSSC=8689=TSK=VVC=BG
250
LI, CHEUNG, AND MAYR
TABLE 2
coordination polymers from silver(I) salts and diisocyano-
menthane (7).
Selected Bond Lengths (A) and Bond Angles (3) for
(a) Complex 1a and (b) Complex 2
(a) Complex 1a
Structures
Ag1(1)}C(1)
N(1)}C(1)
N(1)}C(2)
N(2)}C(8)
2.098(5)
1.125(6)
1.421(5)
1.140(6)
Ag(1)}C(15)
N(3)}C(15)
N(3)}C(16)
N(4)}C(22)
2.092(5)
1.128(6)
1.419(6)
1.129(8)
The crystal structures of 1a and 2 were determined by
single-crystal X-ray crystallography. Drawings of the metal
complex units of 1a and 2 with the atomic numbering
schemes are shown in Figs. 1 and 2. Selected bond lengths
and bond angles are listed in Table 2.
C(1)}Ag(1)}C(15)
Ag(1)}C(15)}N(3)
C(15)}N(3)}C(16)
156.1(2)
174.0(4)
177.3(5)
Ag(1)}C(1)}N(1)
C(1)}N(1)}C(2)
176.6(5)
176.2(5)
Complex 1a may be described as a two-coordinate sil-
ver(I) complex with a strongly distorted linear coordination
geometry. The isocyanide ligands are coordinated to the
silver center with an average Ag}C bond distance of 2.09 A.
The angle between the two isocyanide ligands, C(1)}Ag(1)}
C(15), deviates by almost 243 from linearity. This distortion
from linearity is caused by the interaction of the cationic
silver center with the tetra#uoroborate anion. The shortest
Ag}F distance, Ag(1)}F(1*) at 1!x,!y,!z, is 2.534(8) A,
(b) Complex 2
2.076(3)
Ag1(1)}C(1)
Ag(1)}O(1)
N(1)}C(3)
C(2)}C(6*)?
S(1)}O(2)
Ag(1)}N(2)
N(1)}C(1)
N(2)}C(2)
S(1)}O(1)
S(1)}O(3)
2.194(3)
2.478(3)
1.413(4)
1.446(5)
1.419(3)
1.137(4)
1.132(4)
1.443(3)
1.430(3)
N(2)}Ag(1)}C(1)
Ag(1)}N(2)}C(2)
N(2)}C(2)}C(6)
147.4(1)
159.7(3)
175.6(5)
Ag(1)}C(1)}N(1)
C(1)}N(1)}C(3)
Ag(1)}O(1)}S(1)
172.5(3)
176.6(4)
117.3(2)
slightly longer than the Ag}F distances in AgF and Ag F
(2.46 and 2.45 A) (13). It may be concluded that the interac-
tion between the cation and the anion is primarily electros-
ꢁ
?C(6*) at 1#x,!1#y, z.
tatic in nature. The crystal structure of 1a consists of
interdigitated stacks of bis(arylisocyanide)silver complexes,
whereby the BF anions are located alternatingly on oppo-
ꢃ
site sides of the stacks (Fig. 3). Because of the overlap of the
aromatic n systems of adjacent rows of metal complexes, the
repeat distance between the silver atoms is 6.6401(8) A,
which is about twice the typical n stacking distance of
aromatic compounds. The space between the interdigitating
phenyl rings and the bis(isocyanide)silver groups is "lled by
a benzene molecule of crystallization. The distances between
the silver atom Ag(1) and the three nearest benzene carbon
atoms, C(29*), C(30*), and C(31*) at !x,!y,!z, are
3.22(1), 2.955(8), and 3.33(1) A, respectively. These distances
are signi"cantly longer than the shortest Ag}C contacts in
AgClO ) C H (2.50 and 2.63 A) (14).
ꢃ
ꢄ ꢄ
Compound 2 is a one-dimensional solid. The crystal
structure is made up of linear chains of [Ag(4-CN}
C H }3,5-(i-C H ) }CN) ](SO CF ) units. Each silver
ꢄ ꢁ
ꢅ ꢆ ꢁ
ꢁ
ꢅ
ꢅ
atom is connected to one isocyanide group and one nitrile
FIG. 3. Segment of the crystal structure of 1a showing the interdigita-
FIG. 2. ORTEP drawing of two molecular units of compound 2. The tion of the phenyl rings and the sandwiching of the enclosed benzene
thermal ellipsoids are shown at the 30% probability level. molecule between two silver atoms.

JSSC=8689=TSK=VVC=BG
MOLECULAR COMPLEXES OF Ag(I) SALTS AND ISOCYANIDE
251
FIG. 4. Views of segments of the crystal structure of 2. (a) Segment of three layers viewed along the a axis. (b) Segment of a single layer viewed
approximately along the c axis. (c) View of the segment shown in (b) viewed approximately along the a}b vector. (d) Portion of a double chain highlighting
the interactions between the silver and tri#ate ions.
group of two consecutive bridging ligands (Ag(1)}C(1) electrostatic in#uence of the tri#ate ions (Ag(1)}Ag(1*) at
2.076(3) A and Ag(1)}N(2) 2.194(3) A). Thus within a single !x,!y, 1!z, 4.050(1) A). When the same segment is
chain, the cyanoisocyanoarenes all point in the same direc- viewed along the direction of the chains (Fig. 4c), one can
tion (Fig. 2). The chains are organized into layers (Fig. 4a), clearly discern that the aromatic rings within each chain are
whereby adjacent chains are running in opposite directions. all nearly perfectly coplanar while the silver atoms are
Within the layers, pairs of chains are held together by protruding toward the center of the double chains. Figure
electrostatic interactions between the silver ions and the 4d shows a side view of a double chain highlighting the
tri#ate ions. The #anking sides of these double chains are electrostatic Ag}O}Ag}O &&quadrangle''. One oxygen atom
engaged in n stacking interactions. The segment of a single of each tri#ate ion, O(1), has a short contact to a silver atom,
layer shown in Fig. 4b includes three double chains with two Ag(1), within its associated chain (2.468(3) A) and a just
n stacking interfaces. The most conspicuous local structural slightly longer contact to a silver atom Ag(1*) in the neigh-
feature within the double chains is the presence of pairs of boring chain (2.627(3) A). Similar Ag}oxyanion dimers have
silver atoms which are pulled toward each other by the been observed previously in cyclic dicyanodiphenylacetylene

JSSC=8689=TSK=VVC=BG
252
LI, CHEUNG, AND MAYR
complexes of Ag(I) (15). A double-chain structure featuring
alternating n stacking and ionic interactions is also present
in the one-dimensional solid [AgX(3,6-di(4-pyridyl)-1,2,4,5-
tetrazine)(MeCN)] (X"BF , PF ) (16). The possibility that
2. (a) J. S. Miller and A. J. Epstein, Prog. Inorg. Chem. 20, 1 (1976); (b) R.
Robson, B. F. Abrahams, S. R. Batten, R. W. Gable, B. F. Hoskins, and
J. Liu, in &&Supramolecular Architecture'' (T. Bein, Ed.), ACS Sympo-
sium Series 499, Am. Chem. Soc., Washington, DC, 1992; (c) O. M.
Yaghi, H. L. Li, Davis, D. Richardson, and T. L. Groy, Acc. Chem. Res.
31, 474 (1998); (d) P. J. Hagrman, D. Hagrman, and J. Zubieta, Angew.
Chem., Int. Ed. 38, 2638 (1999).
3. (a) F. A. Cotton and Y. Kim, J. Am. Chem. Soc. 115, 8511 (1993); (b) R.
E. Melendez, C. V. K. Sharma, M. J. Zaworotko, C. Bauer, and R. D.
Rogers, Angew. Chem., Int. Ed. Engl. 35, 2213 (1996); (c) B. F. Abraham,
S. R. Batten, H. Hamit, B. F. Hoskins, and R. Robson, Angew. Chem.,
Int. Ed. Engl. 34, 820 (1996); (d) G. L. Ning, M. Munakata, L. P. Wu,
M. Maekawa, T. Kuroda-Sowa, Y. Suenaga, and K. Sugimoto, Inorg.
Chem. 38, 1376 (1999).
4. (a) L.-F. Mao and A. Mayr, Inorg. Chem. 35, 3183 (1996); (b) J. Guo
and A. Mayr, Inorg. Chim. Acta 261, 141 (1997); (c) A. Mayr and L.-F.
Mao, Inorg. Chem. 37, 5776 (1998); (d) A. Mayr and J. Guo, Inorg.
Chem. 38, 921 (1999); (e) K. Y. Lau, A. Mayr, and K.-K. Cheung, Inorg.
Chim. Acta 285, 223 (1999).
5. W. P. Fehlhammer and M. Fritz, Chem. Rev. 93, 1243 (1993).
6. (a) L. Malatesta and F. Bonati, &&Isocyanide Complexes of Transition
Metals.'' Wiley, New York, 1969; (b) E. Singleton and H. E. Oos-
thuizen, Adv. Organomet. Chem. 22, 209 (1983).
ꢃ
ꢄ
the silver atoms in 2 are pushed toward the center of the
double chains by steric repulsions from the phenyl rings of
the adjacent double chains can be dismissed on the basis of
the relatively long Ag}C(arene) distances, ranging from
3.83}4.08 A. The local distortions of the linear CN}Ag}CN
chains also reveal a marked di!erence in the structural
robustness of the isocyanide}silver and nitrile}silver link-
ages. As the Ag atom is &&pulled out'' from the ideally linear
N}C}Ag}N}C grouping, the isocyanide carbon atom &&fol-
lows'' more than the nitrile nitrogen atom, causing the
metal}isocyanide group Ag(1)}C(1)}N(1) to bend by only 83
while the metal}nitrile group Ag(1)}N(2)}C(2) bends by 203.
This result provides another indication that metal}nitrile
bonds are probably not reliable linkages in situations where
structural robustness is desired. We have previously ob-
served the &&collapse'' of a normally linear Cu}N}C cop-
per}nitrile angle to only 1083 under the in#uence of crystal
packing forces (4a, 4c).
From a general perspective, cyanoisocyanoarenes may be
viewed as expanded neutral analogues of cyanide. In anal-
ogy to the coordination chemistry of cyanide (17), they can
be expected to give rise to a potentially rich variety of
coordination polymers. In this sense, the linear coordina-
tion polymer 2 is an expanded analogue of silver(I) cyanide,
whose solid-state structure consists of linear}Ag}C}N}Ag}
chains (18). In the context of this analogy, the structure of
7. D. Fortin, M. Drouin, M. Turcotte, and P. D. Harvey, J. Am. Chem.
Soc. 119, 531 (1997).
8. (a) D. Venkataraman, G. B. Gardner, S. Lee, and J. S. Moore, J. Am.
Chem. Soc. 117, 11600 (1995); (b) G. B. Gardner, Y.-H. Kiang, S. Lee, A.
Asgaonkar, and D. Venkataraman, J. Am. Chem. Soc. 118, 6946 (1996);
(c) W. Choe, Y.-H. Kiang, Z. Xu, and S. Lee, Chem. Mater. 11, 1776
(1999).
9. Z.-L. Lu, A. Mayr, and K.-K. Cheung, Inorg. Chim. Acta 284 (1999)
205.
10. DENZO, in &&The HKL Manual*A description of programs DENZO,
XDISPLAYF, and SCALEPACK,'' written by D. Gewirth, with the
cooperation of the program authors Z. Otwinowski and W. Minor,
1995.
2 may also be compared with the structure of AgCN ) 11. TeXsan: Crystal Structure Analysis Package, Molecular Structure
Corp., 1985 & 1992.
2AgNO (19). The structure of this mixed salt features
ꢅ
12. (a) M. E. Squires and A. Mayr, Inorg. Chim. Acta 264, 161 (1997); (b) S.
linear}Ag}C}N}Ag}chains separated by interspersed
Wang, A. Mayr, and K.-K. Cheung, J. Mater. Chem. 8, 1561 (1998);
AgNO units, whereby the oxygen atoms of the nitrate ions
(c) L. Yang, K.-K. Cheung, and A. Mayr. J. Organomet. Chem. 585, 26
(1999).
ꢅ
form relatively short contacts (3.0}3.2 A) with the silver
atoms in the neutral AgCN chains.
13. &&Gmelins Handbuch der Anorganischen Chemie,'' Silber, Teil B1,
p. 291. Verlag Chemie, Weinheim, 1971.
14. H. G. Smith and R. E. Rundle, J. Am. Chem. Soc. 80, 507 (1958).
15. K. A. Hirsch, S. R. Wilson, and J. S. Moore, J. Am. Chem. Soc. 119,
10401 (1997).
16. M. A. Withersby, A. J. Blake, N. R. Champness, P. Hubberstey, W.-S.
Li, and M. Schroder, Angew. Chem., Int. Ed. 36, 2327 (1997).
17. K. R. Dunbar and R. A. Heintz, Prog. Inorg. Chem. 45, 283
(1997).
18. (a) C. D. West, Z. Kristallogr. 90, 555 (1935); (b) &&Gmelins Handbuch
der Anorganischen Chemie,'' Silber, Teil B3, p. 299. Verlag Chemie,
Weinheim, 1973.
ACKNOWLEDGMENTS
Support for this work by the Committee on Conference and Research
Grants of The University of Hong Kong and by the Hong Kong Research
Grants Council is gratefully acknowledged.
REFERENCES
1. J. C. Bailar, in &&Prep. Inorg. Reactions'' (W. L. Jolly, Ed.), Vol. 1,
pp. 1}25. Interscience, New York, 1964.
19. D. Britton and J. D. Dunitz, Acta Crystallogr. 19, 815 (1965).