Ligand Influences on the Supramolecular Chemistry of Simple Gold(I) Complexes: Mononuclear (Isonitrile)gold(I) Complexes

Article abstract of DOI:10.1515/znb-1996-0606

A series of (isonitrile)gold(I) complexes has been synthesized: (MeNC)AuX (X = Cl 1a, 1 1c), (t-BuNC)AuBr 2b, (PhNC)AuX (X = Cl 3a, Br 3b, 1 3c, SCN 3d), (MesNC)AuCl 4a [mes=mesityl], and (MeOC(O)CH₂NC)AuX (X = Cl 5a, Br 5b, I 5c, SCN 5d). The chlorides were prepared by the reaction of (Me₂S)AuCl with equimolur amounts (or with an excess) of the corresponding isonitrile. The bromides, iodides and thiocyanates were obtained from the reaction of (RNC)AuCl with K⁺K^- (X = Br, I, SCN) in the two-phase system H₂O/CH₂Cl₂. The molecular and crystal structures of 1a, 2b, 3a-c, 4a, and 5a-c have been determined by X-ray diffraction methods. In the solid state the molecules are aggregated through short Au-Au contacts into dimers (4a and 5c), chains (1a, 2b and 3a-c) or sheets (5a and 5b). The influence of the isonitrile and halide ligands on the type and strength of the intermolecular Au-Au contacts is discussed.

Full text of DOI:10.1515/znb-1996-0606

Ligand Influences on the Supramolecular Chemistry of Simple Gold(I)
Complexes: Mononuclear (Isonitrile)gold(I) Complexes
W olfgang Schneider, Klaus Angerm aier, A lexander Sladek, H ubert Schm idbaur*
Anorganisch-chemisches Institut der Technischen Universität München,
Lichtenbergstrasse 4, D-85747 Garching. Germany
Dedicated to Professor Max Herberhold on the occasion o f his 60th birthday
Z. Naturforsch. 51 b, 790-800 (1996); received December 22, 1995
Gold(I) Complexes, Isonitrile Complexes, Auriophilicity, Crystal Structure
A series of (isonitrile)gold(I) complexes has been synthesized: (MeNC)AuX (X = Cl la,
I lc), (f-BuNC)AuBr 2b. (PhNC)AuX (X = Cl 3a. Br 3b. I 3c. SCN 3d), (MesNC)AuCl 4a
[mes=mesityl], and (Me0 C(0 )CH2NC)AuX (X = Cl 5a. Br 5b. I 5c. SCN 5d). The chlorides
were prepared by the reaction of (Me2S)AuCl with equimolar amounts (or with an excess) of
the corresponding isonitrile. The bromides, iodides and thiocyanates were obtained from the
reaction of (RNC)AuCl with K+X- (X = Br, I, SCN) in the two-phase system H2O/CH2CI2.
The molecular and crystal structures of la. 2b. 3a-c, 4a, and 5a-c have been determined by
X-ray diffraction methods. In the solid state the molecules are aggregated through short Au-Au
contacts into dimers (4a and 5c), chains (la, 2b and 3a-c) or sheets (5a and 5b). The influence of
the isonitrile and halide ligands on the type and strength of the intermolecular Au-Au contacts
is discussed.
In tro d u ctio n
only recently that advanced studies including rela-
tivistic and correlation effects w ere able to account
for the “auriophilicity” phenom enon [42 - 47].
In recent years (isonitrile)gold(I) com plexes have
attracted increasing attention because of their use
in new dom ains of applications. (Isonitrile)gold(I)
alkyl com plexes can be used as M O CV D precur-
sors for the deposition of thin gold-film s [1 - 3], and
(isonitrile)gold(I) alkynyls and halides were shown
to form a new type of liquid crystalline phases [4 -
9]. The ability of (isonitrile)gold(I) halides to give
rise to liquid crystalline phases is thought to arise
from the presence of weak gold-gold interactions
in these system s [9], w hich can be com pared in
strength to hydrogen bonds [10 - 12]. Prior to these
new areas of application, (isonitrile)gold(I) com -
plexes were used as im portant starting m aterials for
carbene com plexes [ 13 - 25] and related com pounds
[26 - 34],
G old(I) com plexes of the type L-A u-X (L = neu-
tral donor ligand, X = halide or pseudohalide) can
be aggregated into dim ers, oligom ers or polymers.
The degree of oligom erization is clearly determ ined
by a num ber of factors, am ong w hich the steric ef-
fect o f the ligands is the m ost obvious. In order
to learn m ore about other contributions to aurio-
philicity, a study of the structural chem istry of com -
plexes w ith “slim ” ligands was undertaken, which
was thought to provide a better insight into the role
of the nature of X and L. To date, only few (isoni-
trile)gold(I) com plexes have been structurally char-
acterized [48 - 54]. The sm all methyl group (1),
the bulky r-butyl group (2), the flat phenyl (3) and
m esityl groups (4), were chosen in this work as sub-
stituents for the neutral isonitrile ligands and C l-
(a), B r" (b), I- (c) and SC N - (d) as the anions
X “ . The carboxym ethylester derivatives (5) serve
as m odels for functional isonitriles.
The structural data available for gold(I) com -
plexes show that gold-gold interactions are ubi-
quitous in the solid phases of these com pounds,
and that they may even govern the supram olecular
structure of the m aterials [35 - 41 ]. Classical theory
of chem ical bonding does not offer an explanation
for this type of gold-gold interactions, and it was
R esults
The (isonitrile)gold(I) chlorides la , 3a, 4a and 5a
w ere obtained in high yield (> 75% ) following the
* Reprint requests to Prof. Dr. H. Schmidbaur.
k
0939-5075/96/0600-0790 $ 06.00
©
1996 Verlag der Zeitschrift für Naturforschung. All rights reserved.
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider et al. • Ligand Influences on the Supramolecular Chemistry of Simple Gold(I) Complexes
791
Table I. Crystallographic data for (MeNC)AuCl (la). (r-BuNC)AuBr (2b) and (PhNC)AuCl (3a).
Compound
la
2b
3a
Empirical formula
Formula weight
Crystal system
Space group (No.)
a [A]
QHyAuBrN
360.01
orthorhombic
Pnma (No.62)
13.168(1)
9.757(1)
6.620(1)
90
C2H3AuC1N
273.47
monoclinic
P2i (No.4)
4.116(1)
6.198(1)
9.031 (1)
90
C7H^AuC1N
335.54
monoclinic
P2|/c (No. 14)
10.935(2)
6.458(1)
12.253(2)
90
b [A]
c [A]
Q[°]
93.25 (1)
90
230.02 (6)
3.948
2
236
323.6
-56
90
90
850.5(1)
2.85
4
640
219.1
-68
115.40(1)
90
781.6
2.871
4
600
190.8
-68
ß[ °]
7[°J3
v [A3]
/9calc [gem ‘ ]
Z
F(000)[e]
//(M o-K q ) [cm -1 ]
T[°C]
Diffractometer
Scan
Enraf Nonius CAD4
0 - 0
0 < /z < 5, 0 < £ < 8,
Enraf Nonius CAD4
Enraf Nonius CAD4
0 - 0
-13 < h < 13,0 < k < 8
0 -0
hkl Range
0 < h < 16,0 < £ < 12,
-8 < / < 8
1896
0 < / < 15
1920
-11 < / < 11
1136
Measured reflections
Unique reflections
Observed reflections
1108
1038
960
862
1526
1301
0.0134
4cr(F0)
217
- 1 9
empirical
0.4901 / 0.9954
0.0240
0.1042
4cr(F0)
25
- / 3
empirical
0.1062/0.9982
0.0826
0.0207
4<t(F0)
111
5 1 -
no
^int
F0 >
Refined parameters
H-Atoms (found/calcd)
Absorption corr.:
Tmin / Tmax
R *
0.0290
0.0837
0.0235
0 0288
Rw **
Weighting scheme ***
Pfin(max/min) [eA-3]
/= 1.0000 / k = 0.000391
+ 1 8 .5 0 /- 12.42
/= 1.0000 / k = 0.000523
+ 1. 13/ - 1.32
/= 1.0000 /* = 0.000117
+ 1.2 6 /-0 .8 7
*R = E(IIFol-IFcll)/EIFol; *~Rw = [£(vv(IF0I-IFcI)2) /I > ( F ^ ] i/2;
= l/[C72(F0) + k F2].
general synthetic route illustrated in eq. (1).
products were isolated as colourless crystals from
dichloromethane solutions by careful addition of
pentane. The compounds are light- and airstable
and can be stored at room temperature. Only the
iodides and thiocyanates undergo slow decompo-
sition after a period of several months, as indi-
cated by the change in their colour. The solubil-
ity in dichloromethane increases in the sequence
RNCAuCl < RNCAuBr ~ RNCAuSCN < RN-
CAuI, following the increasing covalent character
of the Au-X bond. The compounds were identi-
fied by standard spectroscopic methods and elemen-
tal analysis. In the IR spectra, the CN stretching
frequencies of the isocyanide ligands were moni-
tored as listed together with the NMR data in the
(M e2S)AuCl + RNC -*■ (RNC)AuCl + Me2S (1)
The (isonitrile)gold(I) bromides 2b, 3b and 5b,
iodides lc, 3c and 5c, and thiocyanates 3d and 5d
were prepared in virtually quantitative yield by stir-
ring a solution of (RNC)AuCl in dichloromethane
with a solution of K+X - (X = Br, I, SCN) in water
for several hours at ambient temperature (eq.(2)).
(RNC)AuCl + KX -> (RNC)AuX + KC1
(X = Br, I, SCN)
(2)
This method was first reported by Swan
and coworkers, but had only been applied
to (phosphane)gold(I) complexes [55, 56]. The
Unauthenticated
Download Date | 3/15/17 11:37 PM

792
W. Schneider et cd. • Ligand Influences on the Supramolecular Chemistry o f Simple Gold(I) Com plexes
Fig. la. Molecular structure of (MeNC)AuCl (la), with
atomic numbering. Selected bond lengths (A) and angles
(°): Au-Cl 2.259(7), Au-Cl 1.95(2), Cl-N 1.10(3), N-C2
1.45(4), Cl-Au-Cl 178.8(5), N-Cl-Au 177(6), C2-N-C1
163(5).
Fig. 2a. Molecular structure of (r-butylisonitrile)gold(I)
bromide (2b), with atomic numbering. Selected bond
lengths (A) and angles (°): Au-Br 2.370(1), Au-
C1 1.939(8), Cl-N 1.13(1), N-C2 1.45(1), Cl-Au-Br
177.2(3), N-Cl-Au 177.5(8), C2-N-C1 177.9(8).
Fig. lb. Supramolecular structure of la. Polymeric zig
zag chains with antiparallel arrangement of the molecules
[Au-Au'3.637(1) A],
Fig. 2b. Supramolecular structure of 2b. Polymeric zig
zag chains with antiparallel arrangement of the molecules
[Au-Au'3.689(1)].
Experimental Part. The 'H and l3C NMR spectra
show coupling of their nuclei with 14N in most
cases, a feature characteristic for many isonitriles
and their complexes.
similar to the situation in alkynyl complexes [53,
54, 58, 59], Further details are listed in the caption
of Fig. la and in Table I. An examination of the cell
packing shows zig zag chains of molecules with the
monomeric units arranged in an antiparallel fash-
ion (Fig. lb). The Au-Au contacts are surprisingly
long [3.637(1) A], probably due to the close an-
tiparallel packing in layers, which forces the metal
atoms into alternating position above and below the
plane defining the center of the layer.
(MeNC)AuCl, la, has been characterized previ-
ously, but the molecular and crystal structure had
not been determined. Crystals of la are monoclinic,
space group P2j, with 2 molecules in the unit cell.
The individual molecule is rod-like with no crys-
tallographically imposed symmetry. The Cl-Au-C
angle is close to 180° [178.8(5)°], but the C-N-C-
angle is smaller at 163(5)°. The Au-C bond dis-
tance [1.95(2) A] is relatively short compared to the
values of (phosphine)gold(I) alkyl complexes like
(Ph3P)AuCH3 [Au-C 2.124(3) A] [57], This short-
ening may reflect a backbonding from gold to the
(f-BuNC)AuBr, 2b, is isostructural to the known
chloride analogue (r-BuNC)AuCl [49]. The struc-
ture of the bromide complex (2b) has been de-
termined nevertheless because it allows for the
isonitrile ligand, but is more likely associated with first time the determination of an Au-Br bond dis-
tance in an (isonitrile)gold(I) complex. It was found
the sp-hybridization of the isonitrile carbon atom.
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
Table II. Crystallographic data for (PhNC)AuBr / 1(3b, 3c) and (MesNC)AuCl (4a).
793
Compound
3b
3c
4a
Empirical formula
Formula weight
Crystal system
C7FhAuBrN
380.00
CvFLAuIN
426.99
CioHn AuNCl
377.61
monoclinic
P2,/c (No. 14)
10.047(1)
16.612(2)
6.904(1)
90
110.07(1)
90
1082.3 (2)
2.32
triclinic
Pi (No.2)
9.370(1)
10.222(1)
10.679(1)
103.43 (1)
115.44(1)
96.26(1)
872.7 (1)
3.25
triclinic
Pi (No.2)
9.152(1)
10.059(1)
10.109(1)
102.68 (1)
96.57(1)
114.09(1)
806.8 (2)
3.13
Space group (No.)
a [A]
b [A]
c [A]
a [° ]
ß[ °]
7 [°J
V [A3]
Pcalc [gem ■]
z
4
4
4
F(000) [e]
li(M o-Kc) [cm-1]
T [°C]
Diffractometer
Scan
672
231.0
-62
Enraf Nonius CAD4
u>
744
203.2
-68
Enraf Nonius CAD4
0
696
137.9
-68
Enraf Nonius CAD4
LÜ
hkl Range
0 < h < 11,-12 < k < 12, 0 < / i < + l 1,-13 < £ < + 1 3 ,
-8 < h < 8 ,0 < £ < 21
0 < / < 12
2456
2044
1735
-12 < / < 12
3480
3110
-13 < /< +13
3776
3494
Measured reflections
Unique reflections
Observed reflections
2587
3054
0.1042
4a (F0)
181
0.0327
4<t(F0)
181
- / 5
empirical
0.6006 / 0.9982
0.0272
0.0207
^int
Fo >
4<t(F0)
Refined parameters
H-Atoms (found/calcd)
Absorption corr.:
118
- / 11
empirical
0.3222 / 0.9987
0.0384
- / 5
empirical
0.3319/0.9989
0.0305
Tmin / Tmax
R *
0.0346
/ = 1.0000 Ik = 0.000304
+ 1.46/- 1.35
0.0298
unit weights
+ 0.72 / -0.96
0.0487
/ = 1.0000 Ik = 0.006240
+ 1.24 / -1.91
Rw
Weighting scheme ***
Pfin(max/min) [eA-3]
*R =£(IIFol-IFcll)/£IFol; **RW= [£ (w (IF 0I-IFcI)2)/£ w (F 2)]1/2;
= 1/[o-2(Fo) + k pZ].
[2.370(1) Ä] to be comparable to the data for (phos- are aggregated to form a zig-zaging chain with a se-
phine)gold(I) complexes (average 2.40 A) [60-63]. quence of the monomers in an antiparallel arrange-
The C-Au-Br angle is virtually linear at 177.2(3)°
(Fig. 2a). In the lattice the packing of the molecules
ment. The planes of the phenyl groups are parallel
by symmetry on both sides of the chain. (Fig. 3b).
is similar to that found in la and in the chloride The intra-chain gold-gold contacts [3.463(1) A] are
analogue [49]. The monomeric units form zig-zag shorter by 0.174 A as compared with la, but still
rather long.
chains with a sequence of anti-parallel arrange-
ments. There are only very weak Au-Au interac-
tions as suggested by long [Au-Au = 3.689(1) A]
distances (Fig. 2b).
The bromide 3b crystallizes with two crystallo-
graphically independent molecules in the asymmet-
ric unit. In the lattice there are puckered chains
with an antiparallel arrangement of the neighbour-
The (phenylisonitrile)gold(I) halides 3a-c are not
isomorphous (Table I and II). In the chloride 3a ing molecules (Fig. 4). The intra-chain gold-gold
(Fig. 3a), all molecular units are crystallographi- contacts are not equivalent [Aul-Aul' = 3.610(1)
A, Au2-Au2' = 3.507(1) A, Aul-Au2 = 3.649(1)
A], with an average of 3.589 A. This mean value
cally equivalent, with a C-Au-Cl angle of 178.5(3)°
and a Au-Cl distance of 2.254(2) A. The molecules
Unauthenticated
Download Date | 3/15/17 11:37 PM

794
W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
Fig. 4. Supramolecular structure of (PhNC)AuBr (3b).
Unlike in 3a, the phenyl groups are rotated by 90°. Se-
Fig. 3a. Molecular structure of (PhNC)AuCl (3a), with
atomic numbering. Selected bond lengths (A) and angles
(°): Au-Cl 2.254(2), Au-Cl 1.925(7), Cl-N 1.142(9), N-
C2 1.396(8), Cl-Au-Cl 178.5(3), N-Cl-Au 177.0(9), C2-
N-Cl 177(1).
lected bond lengths (A) and angles (°): Intermolecu-
lar: Aul-Aul' 3.610(1), Aul'-Au2 3.649(1), Au2-Au2'
3.507(1); Intramolecular: Aul-Brl 2.360(1), Aul-Cll
1.94(1), N l-C ll 1.15(1), N1-C12 1.40(1), Au2-Br2
2.355(1), Au2-C21 1.94(1), N2-C21 1.13(1), N2-C22
1.40(1), Cl 1-Aul-Brl 177.5(2), Nl-Cl 1-Aul 178.3(8),
C12-N1-C11 179(1), C21-Au2-Br2 176.0(3), C22-N2-
C21 176.4(8), N2-C21-Au2 176.5(9).
Fig. 3b. Supramolecular structure of 3a. Polymeric /ig
zag chains with antiparallel arrangement of the molecules
[Au-Au 3.463(1) A].
is thus larger than in the chloride homologue 3a
(above). However, unlike in 3a, every second phenyl
group on each side of the chain in 3b is rotated by
about 90°, bringing neighbouring phenyl groups in
an approximately perpendicular arrangement. The
two Au-Br distances have an average of 2.357 A,
very similar to the value found for 2b.
Fig. 5. Molecular structure of (PhNC)AuI (3c), with
atomic numbering (only one of the two crystallograph-
ically independent molecules is shown). Selected bond
lengths (A) and angles (°): Aul-Aul' 3.875(1), Au2-
Au2' 3.640( 1), Au 1-Au2 3.802( 1), Au 1-112.524( 1), Au 1-
C ll 1.93(1), N l-C ll 1.19(2), N1-C12 1.38(1), Au2-I2
2.523(1), Au2-C21 1.92(1), N2-C21 1.17(1), N2-C22
1.38(1), Cl 1-Aul-Brl 177.1(3), C12-N1-C11 177(1).
N1-C11-Au 1 176.0(8), C21-Au2-Br2 175.3(4), C22-N2-
C21 177.8(9), N2-C21-Au2 176.(1).
The (phenylisonitrile)gold(I) iodide 3c (Fig. 5)
is isostructural to the bromide complex, 3b. with
the same sequential pattern in the chain struc-
ture. Interestingly, the intra-chain Au-Au contacts
[3.640(1), 3.802(1) and 3.875(1) A, average 3.772
A] are longer than those in 3a and 3b. indicating
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider ei al. • Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
795
be noted that 4a shows a relatively long Au-C bond
[1.98(1) A] as compared to other (isonitrile)gold(I)
halides, probably also owing to steric effects.
The isonitrile derived from glycine methylester,
Me0C(0)CH2NC, was chosen as a ligand with a
polar side group of limited steric influence. The
usual synthetic pathways were followed to prepare
the gold(I) complexes 5a-d of this ligand.
Fig. 6. Dimer of (MesNC)AuCl (4a), with an intermolec-
ular Au-Au’distance of 3.336( 1) A. Selected bond lengths
(A) and angles (°) in the monomer: Au-Cl 2.262(3),
Au-CI 1.98(1), Cl-N 1.10(1), N-C2 1.35(1), Cl-Au-Cl
175.0(4), N-Cl-Au 176.0(8), C2-N-C1 174(1).
The three halide complexes 5a-c show two new
structural motifs. The first one is represented by
the chloride and bromide 5a, b which form a novel
isomorphous sheet structure, while the iodide 5c
appears in dimeric aggregates with a crossed orien-
tation of the monomers. The individual molecules
of 5a-c are very similar in their configuration, char-
acterized by a quasi-linear five atom sequence X-
Au-C-N-CFb, as well as in the conformation of the
ester group, i. e. the syn orientation of the carbonyl
oxygen atom and the nitrogen atom, and the syn ori-
entation of the carbonyl oxygen atom and the ester
methyl group (Fig. 7a, 9 and 10).
In the crystal of the chloride and bromide com-
plexes, the monomers are surrounded by three other
monomers and become members of corrugated
sheets (Fig. 7b). These sheets contain a puckered
layer of gold atoms in which each of the crystal-
lographically equivalent metal atoms has contacts
a weakening of the auriophilic bonding. The Au-I
bond distances in 3c, the first Au-I bond lengths
determined for an (isonitrile)gold(I) complex, are
2.524( 1) and 2.523( 1) A, which is somewhat shorter
than found in monomeric Ph3PAuI [2.556( 1) A] [61,
64] or polymeric Me3PAuI [2.583(1) A] [64],
The mesitylisonitrile ligand in the chloride com-
plex 4a is much larger than the phenylisonitrile lig-
and in 3a-c and was expected to exert steric ef-
fects. And indeed a new structure type is realized
which comprises only dimers as shown in Fig. 6.
The Au-Au distance [3.336( 1) A] within the dimers
is shorter than that observed in the chains of any
of the homologues (above). This phenomenon can
also be observed in (phosphine)gold(I) complexes,
where the Au-Au distances in dimers are generally
shorter than in more extended oligomers. It should
Fig. 7b. Supramolecular structure of
(Me0 C(0 )CH2NC)AuCl (5a). The monomers form
chains (perpendicular to the plane of the paper with neigh-
Fig. 7a. Molecular structure ofo(MeOC(0 )CH2NC)AuCl bouring individuals “crossed”), which are associated into
(5a). Selected bond lengths (A) and angles (°): Au-Cl sheets with approaching monomers antiparallel head-to-
2.255(3), Au-Cl 1.96(1), N-Cl 1.11(2), N-C2 1.42(2), tail. Intermolecular contacts Au-Au’ 3.430(1), Au-Au"
3.553(1) A.
Cl-Au-Cl 176.5(4), N-Cl-Au 178(1), C2-N-C1 177(1).
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
796
Au' &
Au
&---- Ö Au"
Au' $
Fig. 8. Projection of the corrugated sheets of gold atoms in
the isomorphous structures of (Me0 C(0 )CH2NC)AuCl / (Me0 C(0 )CH2NC)AuBr (5b), with atomic numbering.
Fig. 9. The monomer in the sheet structure of
Br (5a, 5b). Each gold atom represents a monomer. The
gold atoms form planar zig-zag chains (primary chain,
running vertically), and meandering chains, running hor-
izontally).
Selected bond lengths (A) and angles (°): Au-Br 2.364( 1),
Au-Cl 1.93(1), Cl-N 1.16(2), C2-N 1.38(1), Cl-Au-Br
177.8(4), N-C1-Au 178( 1), C2-N-C1 177(1). The aggre-
gation leads to intermolecular contacts Au-Au' = 3.441 (1)
(primary chain) and 3.622(2) (between primary chains,
see text).
to three other metal atoms (Fig. 8). This connectiv-
ity leads to a quasi-hexagonal array of gold atoms,
with each six-membered ring in a flat, distorted chair
conformation. This structural motiv is reminiscent
of the structure of black phosphorus. In another de-
scription each monomer is part of a zig-zag chain
of molecules with their main axes “crossed like
swords” in heraldic emblems. These chains, running
vertical in Fig. 8 and perpendicular to the paper in
Fig. 7b, are associated into sheets through a parallel
head-to-tail approach of molecules of neighbouring
chains. With the new contacts the gold atoms be-
come part of new meandering chains running per-
pendicular to the primary chain as indicated in Fig.
8. There are two independent Au-Au distances of
3.430(1) and 3.553(1) A in the primary and sec-
ondary chains of the chloro complex 5a, respec-
tively. The data for the bromide (5b) are similar:
3.441(1) and 3.622(1) A.
Fig. 10. The dimers of compound (Me0 C(0 )CH2NC)AuI
(5c). Selected bond lengths (A) and angles (°): Au-Au'
3.191(1), Au-I 2.538(1), Au-Cl 1.94(1), N-Cl 1.17(2).
N-C2 1.41(1), Cl-Au-I 176.2(3), N-Cl-Au 178(1), C2-
N-Cl 178(1).
Discussion
None of the (RNC)AuX complexes reported in
this work is monomeric in the solid state. This
behaviour is reminiscent of the molecularity of
(phosphine)gold halide complexes with small phos-
phines. As also observed for these analogues, only
two of the three possible types of aggregation A-C
(Fig. 11) are realized. The parallel head-to-tail (A )
and the crossed fashion (B) are the recurrent struc-
tural motifs, either seperately [A: la, 2b, 3a-c and
4a; B 5c], or in a combination of both [5a and 5b].
The dimers present in the lattice of
[MeOQOjCFLNClAuI, 5c, have the shortest inter-
molecular Au-Au distance [3.191(1) A] observed in
(isonitrile)gold(I) complexes. The Au-I bond dis-
tance of 2.538(1) A is comparable to that found
in 3c. The monomers are in the “crossed” type of
aggregation with the dihedral angle I-Au-Au-I ap-
proaching 90° (Fig. 10).
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider et al. • Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
Table III. Crystallographic data for (Me0C(0)CH:NC)AuCl / Br / 1(5a-c).
797
Compound
5a
5b
5c
Empirical formula
Formula weight
Crystal system
Space group (No.)
a [A]
HA ]
c [A]
a [°]
C4ILAuC1NO.
331.51
monoclinic
P2,/c (No. 14)
13.291 (2)
8.259 (1)
6.705 (1)
90
C4H,AuBrNO.
375.97
monoclinic
P2i/c (No. 14)
13.427(1)
8.307 (1)
6.758 (1)
90
C4hhAuINO.
422.98
monoclinic
C2/c (No. 15)
25.559 (4)
4.655 (1)
13.866 (2)
90
100.44(1)
90
1621.9 (5)
102.74(1)
90
717.9(1)
101.91 (1)
90
737.6 (1)
ß[°]
7
[°J
V [A3]
Pcalc [gem-3]
Z
3.09
4
3.38
4
3.47
8
F(000) [e]
n(Mo-Ka ) [cm-1]
T [°C]
Diffractometer
Scan
664
252.9
-62
592
209.3
22
1472
218.8
-62
Enraf Nonius CAD4
< 9 -2 0
0 < h < 16, 0 < k < 10,
-8 < / < 8
Enraf Nonius CAD4
Enraf Nonius CAD4
LÜ
-32 < h < 32, -5 < k < 0
-17 < / < 17
0 - 0
hkl Range
-17 < h < 0,-10 < k < 0,
-8 < / < 8
Measured reflections
Unique reflections
Observed reflections
1736
1452
1298
0.0425
1696
1529
1406
0.2711
2360
1681
1546
0.0323
^int
4cr(F0)
4o-(F0)
4<j (F0)
Fo>
Refined parameters
H-Atoms (found/calc.)
Absorption corr.:
82
82
82
- / 5
empirical
- 1 5
empirical
- / 5
empirical
0.2298 / 0.9987
0.0636
0.0878
0.1324/0.9994
0.0567
0.0598
0.1953/0.9996
0.0371
0.0463
Tmin / Tmax
R *
Rw
Weighting scheme ***
Pfin(max/min) [eA-3]
/ = 1.0000 / k = 0.034700
2.08/-2.87
/= 1.00001k = 0.014337
4.47/-3.98
/= 1.0000 /* = 0.008901
2.49/ - l . 96
'R = £(IIFol-IFcll)/£IFol; **r w = [£(w(IF0l-IFcl)2)/£w (F2)]I/2; ***w = l/[cr2(F„) + k F2].
In the series of coordination polymers, the
crossed contacts are also shorter than the parallel
contacts, and it thus appears that this may be taken
as a general feature. It is obvious from the mod-
els (A-C) that steric effects are a minimum for B,
suggesting that the ligand repulsion is the decisive
factor determining the association of the complexes.
X
. x
RNC-----Au------
RNC-----Au-----
X
RNC-----Au-----
X
RNC—
X-----Au------CNR
X
The influence of the nature of the anion X is
found to be smaller, and the variations for the same
structure type are such that the larger halide leads to
nearly equal (e.g. 2a —>2b and 3b —►3c) or to larger
Au-Au contacts (5a —» 5b). This result is not in
agreement with the predictions for isolated dimers
from recent theoretical studies [65]. It is conceiv-
able, however, that the consequences of electronic
effects are overruled by steric effects arising from
Fig. 11. The three principal modes of aggregation of com-
plexes L-Au-X.
(MeNC)AuCN is the only example where, in a com-
bination with mode A, mode C is also realized [48].
If the molecules are aggregated only into dimers (4a
and 5c), the Au-Au distances are the shortest, and
the B-type iodide complex is associated most tightly
as compared to the A-type chloride complex.
Unauthenticated
Download Date | 3/15/17 11:37 PM

798
W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
the incorporation of the dimers into polymers, and
by packing forces.
removed in a vacuum. The residue is crystallized from
dichloromethane by layering the solution with pentane.
Iodide complex lc
Experimental Part
From la (89 mg. 0.33 mmol) and KI (81 mg. 0.49
mmol); yield 102 mg (85%); decomposition temperature
186°C;'H NMR (CDCI3): b = 3.5 ppm. br.. Me; 13C{'H}
NMR (CDCI3): b = 29.7 ppm, s, Me; 144.2, t, './(CN) =
25.7 Hz, NCAu. IR (CH2C12): i/(CN) = 2264 cm-1.
Analysis for C2H3AuIN (M = 364.92)
Calcd C 6.58 H 0.83 N 3.84%,
Found C 6.90 H 0.85 N 3.90%.
General: Conventional glass equipment was used
throughout. Solvents (p.a. grade) were used as received
and all experiments were carried out in air. f-BuNC
was purchased. MeNC [66], PhNC [67]. MesNC [68],
Me0C(0)CH2NC [69], (Me2S)AuCl [70], (MeNC)AuCl
la [71, 72], (f-BuNC)AuCl 2a [49]and (PhNC)AuCl 3a
[73, 74] were prepared according to literature methods.
Preparation of the (isonitrile)gold(I) chloride complexes
Bromide complex 2b
To a solution of (Me2S)AuCl in dichloromethane an
equimolar amount (or an excess) of the corresponding
isonitrile ligand is added. After 1h the solvent is removed
in a vacuum and the colourless residue is crystallized from
a dichloromethane/pentane mixture.
From 2a (150 mg, 0.48 mmol) and KBr (57 mg.
0.48 mmol); yield 154 mg (89%); m.p. 161°C; 'H NMR
(CDCI3): 6 = 1.6 ppm, s, Me; 13C{'H} NMR (CDC13):
b = 29.6 ppm, s, Me; 59.0, t, ]J(CN) = 3.7 Hz, Me3C:
135.9, t, 'y(CN) = 23.0 Hz, NCAu. IR (CH2C12): u(CN)
= 2235.8 cm-1.
Analysis for CsHyAuBrN (M = 360.01)
Calcd C 16.68 H 2.50 N 3.89%,
Found C 16.80 H 2.55 N 3.93%.
Chloride complex 4a
From (Me2S)AuCl (211 mg, 0.72 mmol) and 2,4,6-
(Me)3C6H2NC (104 mg, 0.72 mmol) in CH2C12 (20 mL);
yield 284 mg (75%); m.p. 188°C; 'H NMR (CDC13): b =
2.4 ppm, s, ortho-CHi (6H); 2.3, s, para-CH? (3H); 7.0,
s, meta-H (2H); 13C{'H} NMR (CDCI3): b = 18.5 ppm,
s,orf/w-CH3;21.4,s,para-CHy, 121.6, m,//?so-C; 129.2,
s,ortho-C: 135.9, s,meta-C; 141.8,s,/?ara-C;NCAuwas
not observed. IR (CH2C12): u(CN) = 2214 cm-1.
Bromide complex 3b
From 3a (104 mg, 0.31 mmol) and KBr (37 mg, 0.31
mmol); yield 105 mg (89%); m.p. 177°C; 'H NMR
(CDCI3): b = 1.5-1.6 ppm, m, Ph-H; ,3C{'H} NMR
(CDCI3): b = 124.4 ppm, m, ipso-C; 126.9, s, ortho-
C; 130.0, s, meta-C; 131.6, s, para-C; NCAu was not
observed. IR (CH2C12): u{CN) = 2222 cm“ 1.
Analysis for CyH^AuBrN (M = 379.99)
Calcd C 22.13 H 1.33 N 3.69%,
Found C 22.62 H 1.44 N 3.80%.
Analysis for C,0H,, AuCIN (M = 377.61)
Calcd C 31.78 H2.91 N3.71%,
Found C 31.69 H 2.93 N 3.66%.
Chloride complex 5a
From (Me2S)AuCl (638 mg, 2.17 mmol) and
Me0C(0)CH2NC (215 mg, 2.17 mmol) in CH2C12 (60
mL); yield 582 mg (81%); decomposition temperature
198°C; 'H NMR (CDC13): b = 5.0 ppm, br. s, 2H; 3.8,
s, 3H; 13C{1H} NMR was not recorded because of the
low solubility of 5a. IR (crystal): u{CN) = 2273.1 cm-1;
i^(C02) = 1769.0 cm-1.
Iodide complex 3c
From 3a (177 mg, 0.53 mmol) and KI (88 mg, 0.53
mmol); yield 182 mg (80%); m.p. 126°C; 'H NMR
(CDC13): b = 7.5-7.6 ppm, m, Ph-H; ,3C{'H} NMR
(CDCI3): b = 124.25 ppm, t, './(CN) = 4.5 Hz, ipso-C;
126.8, s, ortho-C; 130.0, s, meta-C; 131.7, s, para-C:
151.0, t, './(CN) = 23.2 Hz, NCAu. IR (CH2C12): u(CN)
= 2216 cm“ 1.
Analysis for C7H,AuIN (M = 426.99)
Calcd C 19.69 H 1.18 N 3.28%,
Found C 19.62 H 1.16 N 3.35%.
Analysis for C4H^AuC1N02 (M = 331.51)
Calcd C 14.48 H 1.51 N 4.22%,
Found C 14.45 H 1.51 N 4.20%.
Preparation of (isonitrile)gold(I) bromide, iodide and
thiocyanate complexes
Thiocyanate complex 3d
A solution of the corresponding (isonitrile)gold(I)
chloride in dichloromethane ( 5 - 10 mL) is stirred with
a solution of equimolar amounts of K+X- (X = Br, I,
SCN) in water ( 5 - 1 0 mL) for 4 h. After separation of
the water phase, the dichloromethane solution is washed
twice with small portions of water and the solvent is
From 3a (120 mg, 0.36 mmol) and KSCN (35 mg.
0.36 mmol); yield 129 mg (100%); m.p. 135°C; 'H NMR
(CDCI3): b = 7.5-7.6 ppm. m. Ph-H; 1'C{1H} NMR
(CDCI3): b = 123.95 ppm. m. ipso-C; 127.0. s, ortho-
C; 130.2. s, meta-C; 132.15, s, para-C; NCAu and SCN
Unauthenticated
Download Date | 3/15/17 11:37 PM

W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry o f Sim ple G old(I) Com plexes
799
were not observed. IR (CH2CI2): i'(CN) = 2228 cm
//(SCN) = 2133 cm“ 1.
Analysis for C«H5AuNiS (M = 358.17)
Calcd C 26.83 H 1.41 N 7.82%,
Found C 26.79 H 1.40 N 7.76%.
Thiocyanate complex 5d
From 5a (100 mg, 0.30 mmol) and KSCN (29 mg,
0.30 mmol); yield 105 mg (89 %); m.p. 117°C; 'H NMR
(CDCI3): b = 3.9 ppm. s, Me; 4.6, br. s, CH2; 13C{'H}
NMR (CDCI3): b = 45.6 ppm, br. s, CH2; 54.2, s, Me;
161.7, s, CO2; NCAu and SCN were not observed. IR
(crystal): u(CN) = 2279.7 cm“ 1; //(SCN) = 2129.7 cm“ 1;
Bromide complex 5b
From 5a (100 mg, 0.30 mmol) and KBr (36 mg, 0.30
mmol); yield 108 mg (95%); m.p. 194°C; *H NMR (de-
acetone): b = 3.85 ppm, s, Me; 5.0, br. s, CH2; 13C{1H}
NMR was not recorded because of the low solubility of
5b. IR (crystal): //(CN) = 2280 cm“ 1; u(C 02) = 1765.5
cm“ 1.
//(C02) = 1759.7 cm“ 1.
Analysis for CsHsAuN,OS (M = 354.13)
Calcd C 16.95 H 1.42 N7.91%,
Found C 16.78 H 1.31 N 7.85%.
Crystal structure determination
Analysis for C4H5AuBrNO (M = 375.97)
Calcd C 12.77 H 1.34 N 3.72%,
Found C 12.98 H 1.31 N 3.58%.
Details of the X-ray structure determination of
the compounds are summarized in the Tables. Fur-
ther information on the structure determinations may
be obtained from Fachinformationszentrum Karlsruhe,
Gesellschaft für wissenschaftlich-technische Information
mbH, D-76344 Eggenstein-Leopoldshafen, Germany, on
quoting the CSD number 59240.
Iodide complex 5c
From 5a (100 mg, 0.30 mmol) and KI (50 mg, 0.30
mmol); yield 110 mg (87%); m.p. 146°C; 'H NMR (dö-
acetone): b = 3.85 ppm, s, Me; 5.0, br. s, CH2; 13C{1H}
NMR (d6-acetone): 6 = 46.35 ppm, t, ‘./(CN) = 9.19 Hz,
CH2; 53.8, s, Me; 163.8, s, C 02; NCAu was not observed.
IR (crystal): //(CN) = 2263.4 cm "1; u(C0 2) = 1749.5
cm-1.
Acknowledgment
This work was supported by Deutsche Forschungsge-
meinschaft and by Fonds der Chemischen Industrie. The
authors are grateful to Mr. J. Riede for establishing the
X-ray data sets.
Analysis for C4Hf;AuIN0 2 (M = 422.98)
Calcd C 11.35 H 1.19 N 3.31%,
Found C 11.18 H 1.13 N 3.06%.
[10] H. Schmidbaur, W. Graf, G. Müller, Angew. Chem.
Int. Ed. Engl. 24,417 (1988).
[1] R. J. Puddephatt, I. Treurnicht, J. Organomet. Chem.
319,129(1987).
[11] H. Schmidbaur, K. Dziwok, A. Grohmann, G.
Müller, Chem. Ber. 122, 893 (1989).
[2] N. H. Dryden, J. G. Shapter, L. L. Coatsworth, P.
R. Norton, R. J. Puddephatt, Chem. Mater. 4, 979
(1992).
[3] P. R. Norton, P. A. Young, Q. Cheng, N. Dryden, R.
J. Puddephatt, Surf. Sei. 307- 309, 172 (1994).
[4] P. Alejos, S. Coco, P. Espinet, New J. Chem. 19, 799
(1995).
[5] M. Benouazzane, S. Coco, P. Espinet, J. M. Martin-
Alvarez, J. Mater. Chem. 5, 441 (1995).
[6] S. Coco, P. Espinet, S. Falagän, J. M. Martin-Alvarez,
NewJ. Chem. 19, 959(1995).
[12] K. Dziwok, J. Lachmann, D. L. Wilkinson, G.
Müller, H. Schmidbaur, Chem. Ber. 122,893 (1990).
[13] H. Schmidbaur, Gmelins Handbuch der Anorgan-
ischen Chemie, Organogold Compounds (Ed. A.
Slawisch) 8th ed., Springer Verlag, Berlin (1980).
[14] W. P. Fehlhammer, W. Fink, J. Organomet. Chem.
414,261(1991).
[15] W. Weigand, U. Nagel, W. Beck, Z. Naturforsch.
43b, 328(1988).
[7] R. Ishii, T. Kaharu, N. Pirio, S.-W. Zhang, S. Taka- [16] G. Banditelli, F. Bonati, S. Calogero, G. Valle, F.
E. Wagner, R. Wordel, Organometallics 5, 1346
(1986).
[17] R. Usön, A. Laguna, J. Vicente, J. Garcia, B.
Bergareche, J. Organomet. Chem. 173, 349 (1979).
hashi, J. Chem. Soc., Chem. Commun. 1995, 1215.
[8] T. Kaharu, R. Ishii, T. Adachi, T. Yoshida, S. Taka-
hashi, J. Mater. Chem. 5, 687 (1995).
[9] T. Kaharu, R. Ishii, S. Takahashi, J. Chem. Soc.,
Chem. Commun. 1994, 1349.
Unauthenticated
Download Date | 3/15/17 11:37 PM

800
W. Schneider et al. ■Ligand Influences on the Supramolecular Chemistry of Simple Gold(I) Com plexes
[18] R. Usön, A. Laguna, J. Vicente, J. Garcia, B.
Bergareche, Inorg. Chim. Acta 28, 237 (1978).
[19] G. Banditelli, F. Bonati, G. Minghetti, Gazz. Chim.
Ital. 107.267 (1977).
[48] S. Esperas, Acta Chem. Scand. A 30, 527 (1976).
[49] D. S. Eggleston, D. F. Chodosh. R. L.. Webb. L. L.
Davis, Acta Crystallogr. C42, 36 (1986).
[50] Ch.-M. Che, W.-T. Wong, T.-F. Lai, H.-L. Kwong.
J. Chem. Soc., Chem. Commun. 1989. 243.
[51] Ch.-M. Che, H.-K. Yip. W.-T. Wong. T.-F. Lai, In-
org. Chim. Acta 197, 177 (1992).
[52] D. Perreault, M. Drouin. A. Michel. P. D. Harvey,
Inorg. Chem. 30, 2 (1991).
[53] G. Jia, R. J. Puddephatt, J. J. Vittal, N. C. Payne.
Organometallics 12, 263 (1993).
[54] G. Jia, N. C. Payne, J. J. Vittal. R. J. Puddephatt.
Organometallics 12, 4771 (1993).
[55] G. E. Coates, C. Kowala, J. M. Swan, Aust. J. Chem.
19, 539 (1966).
[56] C. Kowala, J. M. Swan, Aust. J. Chem. 19, 547
(1966).
[57] P. D. Gavens, J. J. Guy, M. J. Mays, G. M. Sheldrick.
Acta Crystallogr. B 33, 137 (1977).
[20] G. Minghetti, L. Baratto, J. Organomet. Chem. 102.
397 (1975).
[21] G. Minghetti, F. Bonati, J. Organomet. Chem. 54.
C62 (1973).
[22] F. Bonati. G. Minghetti. Synth. React. Inorg. Metal-
Org. Chem. 1, 299(1971).
[23] G. Minghetti. F. Bonati, G. Banditelli, Inorg. Chem.
15,1718 (1976).
[24] G. Banditelli, F. Bonati, S. Calogero, G. Valle, J.
Organomet. Chem. 275, 153 (1984).
[25] F. Bonati, G. Minghetti, Gazz. Chim. Ital. 103,373
(1973).
[26] G. Minghetti, F. Bonati, Angew. Chem. Int. Ed.
Engl. 11,429 (1972).
[27] F. Bonati, G. Minghetti, Inorg. Chim. Acta 9,95
(1974).
[58] D. M. P. Mingos, J. Yau, S. Menzer, D. J. Williams,
Angew. Chem., Int. Ed. Engl. 34, 1894 (1995).
[59] G. Jia, R. J. Puddephatt, J. D. Scott, J. J. Vittal,
Organometallics 12, 3565 (1993).
[60] M. A. Bennett, S. K. Bhargava, K. D. Griffiths, G.
B. Robertson, Angew. Chem., Int. Ed. Engl. 26, 260
(1987).
[28] G. Minghetti, F. Bonati, Gazz. Chim. Ital. 102,205
(1972).
[29] J. Meyer, J. Willnecker, U. Schubert, Chem. Ber.
122,215 (1989).
[30] G. Minghetti, F. Bonati, M. Massobrio, Inorg.
Chem. 14,1974(1975).
[61] P. F. Barron, L. M. Engelhardt, P. C. Healy, J. Oddy.
[31] G. Minghetti, F. Bonati, Inorg. Chem. 13, 1600
(1974).
A. H. White, Aust. J. Chem.40, 1545 (1987).
[32] F. Bonati, G. Minghetti, J. Organomet. Chem. 59. [62] L. G. Kuz'mina, N. V. Dvortsova, Zh. Neorg. Khim.
403 (1973).
36,2021 (1991).
[33] W. Beck, K. Burger, W. R Fehlhammer, Chem. Ber.
104,1816(1971).
[63] H. Schmidbaur, G. Weidenhiller, O. Steigeimann.
G. Müller, Z. Naturforsch.45b, 747 (1990).
[64] S. Ahrland, K. Dreisch, B. Noren, A. Oskarsson.
Acta Chem. Scand. A 41, 173 (1987).
[65] P. Pyykkö, J. Li, N. Runeberg, J. Chem. Soc., Chem.
Commun. 218, 133 (1993).
[66] J. Casanova, R. E. Schuster, N. D. Werner, J. Chem.
Soc. 1963, 4280.
[67] C. Grundmann, Chem. Ber. 91, 1380 (1958).
[68] G. Domschke, R. Beckert, R. Mayer, Synthesis
1977,275.
[34] L. Vaughan, W. A. Sheppard, J. Am. Chem. Soc. 91,
6151 (1969).
[35] R G. Jones, Gold Bull. 14,102 (1981).
[36] R G. Jones, Gold Bull. 19,46 (1986).
[37] H. Schmidbaur, Gold Bull. 23, 11 (1990).
[38] H. Schmidbaur, Interdiscip. Sei. Rev. 17, 213
(1992).
[39] H. Schmidbaur. Pure Appl. Chem. 65,691 (1993).
[40] P.G. Jones, Gold Bull. 16,114 (1993).
[41] K. Angermaier, H. Schmidbaur, Chem. Ber. 127,
2387 0994).
[69] R. Damico, J. M. Nicholson, J. Org. Chem. 38. 3057
(1973).
[70] K. C. Dash. H. Schmidbaur, Chem. Ber. 106, 1221
(1973).
[71] J. Browning, P. L. Goggin, R. J. Goodfellow, J.
Chem. Research (S) 1978. 329.
[72] J. Browning, P. L. Goggin, R. J. Goodfellow, J.
Chem. Research (M) 1978, 4201.
[42] P. Pyykkö, Chem. Rev. 88, 563 (1988).
[43] K. S. Pitzer, Acc. Chem. Res. 12,271 (1979).
[44] O. D. Häberlein, H. Schmidbaur, N. Rösch, J. Am.
Chem. Soc. 116,8241 (1994).
[45] J. K. Burdett, O. Eisenstein, W. B. Schweizer, Inorg.
Chem. 33, 3261 (1994);
[73] A. Sacco, M. Freni, Gazz. Chim. Ital. 86,195(1956).
[74] J. A. McCleverty, M. M. da Mota, J. Chem. Soc..
Dalton Trans. 1973, 2571.
[46] N. Rösch, A. Görling, D. E. Ellis, H. Schmidbaur,
Inorg. Chem. 30. 3986(1991).
[47] J. Li, P. Pyykkö, Inorg. Chem. 32, 2630 (1993).
Unauthenticated
Download Date | 3/15/17 11:37 PM