Gold(i) complexes of cyclodiphosphazanes cis-{RP(μ-NtBu)} 2: Structure of a novel tetranuclear gold(i) macrocycle, [{Au{(o-MeOC6H4O)P(μ-NtBu)} 2}4](ClO4)4

Article abstract of DOI:10.1039/b903075a

Reactions of two equivalents of [AuCl(SMe₂)] with cyclodiphosphazanes cis-{RP(μ-N^tBu)}₂ (1a-1d) produce binuclear gold(i) complexes of the type, [ClAu{RP(μ-N^tBu)} ₂AuCl] (2 R = OC₆H₄

Full text of DOI:10.1039/b903075a

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
Gold(I) complexes of cyclodiphosphazanes cis-{RP(l-NtBu)}2:
structure of a novel tetranuclear gold(I) macrocycle,
[{Au{(o-MeOC6H4O)P(l-NtBu)}2}4](ClO4)4†‡
P. Chandrasekaran,a Joel T. Magueb and Maravanji S. Balakrishna*a
Received 13th February 2009, Accepted 22nd April 2009
First published as an Advance Article on the web 28th May 2009
DOI: 10.1039/b903075a
Reactions of two equivalents of [AuCl(SMe2)] with cyclodiphosphazanes cis-{RP(m-NtBu)}2 (1a–1d)
produce binuclear gold(I) complexes of the type, [ClAu{RP(m-NtBu)}2AuCl] (2 R = OC6H4OMe-o,
3 R = OCH2CH2OMe, 4 R = NEt2, 5 R = NHtBu) in quantitative yield. A similar reaction between
cis-{(o-MeOC6H4O)P(m-NtBu)}2 (1a) and [AuCl(SMe2)] in a 1 : 1 molar ratio afforded the
mono-nuclear complex [ClAu{(o-MeOC6H4O)P(m-NtBu)}2] (6). Addition of two equivalents of CuX
(X = Br, I) to the chloro derivative 2 leads to the formation of bromo, [BrAu{(o-MeOC6H4O)-
P(m-NtBu)}2AuBr] (7), and iodo, [IAu{(o-MeOC6H4O)P(m-NtBu)}2AuI] (8), derivatives through
halogen exchange reactions. A tetranuclear gold(I) macrocycle [Au{(o-MeOC6H4O)P(m-NtBu)}2]4-
(ClO4)4 (9) and a mononuclear gold(I) complex [Au({(o-MeOC6H4O)P(m-NtBu)}2)2]ClO4 (10) were
obtained, respectively, from 1 : 1 and 2 : 1 stoichiometric reactions between 1a and [Au(SMe2)2]ClO4.
Molecular structures of complexes 4, 6, 7, 8 and 9 are confirmed by single-crystal X-ray diffraction
studies. Interestingly, the crystal structure of the tetra-nuclear AuI macrocycle 9 reveals the
-
encapsulation of one ClO4 anion inside the bowl shaped macrocyclic cavity through weak Au ◊ ◊ ◊ O and
C–H ◊ ◊ ◊ O interactions.
for strong anion binding.6 Similarly, metallomacrocycles con-
Introduction
taining a positive charge on the metal centers can also provide
electrostatic interaction to stabilize various anions; however anion
receptors based on a transition metal backbone are limited due
to lack of suitable ligands for generating macrocyclic structures.7
We realized from our recent investigation on the coordination
chemistry of cyclodiphosphazanes that these small P2N2 ligands
are very promising synthons for metallosupramolecular systems.
We showed that the cis-oriented lone pairs on phosphorus in
cyclodiphosphazanes can be utilized as a potential build block
for various metallo-supramolecular structures. Likewise, two cis-
oriented P–Cl bonds in bis(chloro)cyclodiphosphazane could be
used to prepare several macrocycles and polynuclear complexes.8
Notably, metallomacrocycles containing four RhI centers were
isolated from the reaction of cyclodiphosphazane with [Rh(m-
Cl)(CO)2]2.8a,8b Metallopolymers containing CuI (I) and AgI
(II) centers were formed using the cyclodiphosphazane cis-{(o-
MeOC6H4O)P(m-NtBu)}2 with CuX (X = Cl, Br, I) and AgOTf,
respectively (Chart 1).8c,8d In this paper, we describe the synthesis
The rigid nature of the four membered P2N2 ring and the
presence of two reactive cis-oriented P–Cl bonds in the
bis(chloro)cyclodiphosphazanes, cis-[ClP(m-NR)]2, has been ex-
ploited over the last decade for the syntheses of several inor-
ganic macrocycles and cages.1 Macrocycles containing one to
five P2N2 units were produced depending upon the nature of
bifunctional nucleophiles and the reaction conditions.2 These
macrocycles have the potential ability to host ionic or neutral
molecules within their cavities similar to that observed for crown
ethers, calixarenes and azamacrocycles.3 For example, the pen-
tameric macrocycle [HN{P(tBuN)}2]5 acts as a host for spherical
halide anions.4
Synthesis and binding or sensing studies of receptors for anions
has been subject of intense study over past few decades as a
consequence of the significance of anionic species in biochemistry
and the environment.5 Receptors based on an organic backbone
have been much more widely used in host–guest chemistry than
ones having a transition metal backbone. Receptors containing
protonated amine functionalities have been used extensively for
anion encapsulation due to the positive charge on these groups
which facilitates electrostatic and hydrogen bonding interactions
aPhosphorus Laboratory, Department of Chemistry, Indian Institute of
Technology–Bombay, Mumbai, 400076, India. E-mail: krishna@chem.
iitb.ac.in; Fax: +91 22 2572 3480; Tel: +91 22 2576 7181
bDepartment of Chemistry, Tulane University, New Orleans, Louisiana,
LA 70118, USA
† CCDC reference numbers 720414–720418. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b903075a
‡ Dedicated to Prof. C. N. R. Rao on the occasion of his 75th birthday.
Chart 1
5478 | Dalton Trans., 2009, 5478–5486
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
and characterization of gold(I) complexes of cyclodiphosphazane
ligands. The single-crystal X-ray structure of a novel tetra-nuclear
AuI macrocycle with perchlorate encapsulation is also described.
H 4.03, N 3.56. 1H NMR (400 MHz, CDCl3): d 4.28 (m, CH2OP,
4 H), 3.61 (t, OCH2, 4 H, JHH = 1.8 Hz), 3.37 (s, OMe, 6 H), 1.58
1
(s, tBu, 18 H). 31P{ H} NMR (162 MHz, CDCl3): d 102.3 (s).
Synthesis of [ClAu{(Et2N)P(l-NtBu)}2AuCl] (4). As for 2,
using cis-{(Et2N)P(m-NtBu)}2 (1c) (58.7 mg, 0.168 mmol) and
[AuCl(SMe2)] (99.2 mg, 0.336 mmol). Yield: 78% (106 mg,
0.130 mmol). Mp: 204–206 ◦C (dec.). Anal. calcd for
C16H38N4P2Au2Cl2: C 23.62, H 4.70, N 6.88. Found: C 23.87, H
Experimental
Air- and moisture-sensitive compounds were manipulated us-
ing Schlenk techniques under an atmosphere of dry argon.
All glassware used was oven-dried prior to use. Solvents were
purified by conventional procedures and freshly distilled and
degassed prior to use.9 The compounds cis-{(o-MeOC6H4O)P(m-
NtBu)}2 (1a),8a cis-{(MeOCH2CH2O)P(m-NtBu)}2 (1b),8b cis-
{(Et2N)P(m-NtBu)}2 (1c),10 cis-{(tBuNH)P(m-NtBu)}2 (1d)11 and
[AuCl(SMe2)]12 were prepared according to the published pro-
cedures. Starting materials AgClO4, SMe2, CuBr and CuI were
purchased from commercial sources and used as received. The
1
4.85, N 7.95. H NMR (300 MHz, CDCl3): d 3.67 (br s, CH2, 4
H), 3.26 (br s, CH2, 4 H), 1.57 (s, tBu, 18 H), 1.22 (t, CH3, 12 H,
1
JHH = 6.9 Hz). 31P{ H} NMR (121 MHz, CDCl3): d 73.7 (s). MS
(EI, m/z): 837.23 (M + Na).
Synthesis of [ClAu{(tBuHN)P(l-NtBu)}2AuCl]2 (5). As for
2, using cis-{(tBuHN)P(m-NtBu)}2 (1d) (18.0 mg, 0.052 mmol)
and [AuCl(SMe2)] (30.0 mg, 0.102 mmol). Yield: 83% (34.6 mg,
0.043 mmol). Mp: 192–194 ◦C. Anal. calcd for C16H38N4P2Au2Cl2:
C 23.62, H 4.70, N 6.88. Found: C 23.79, H 4.41, N 7.03. 1H NMR
(400 MHz, CDCl3): d 2.58 (s, NH, 2 H), 1.60 (s, NHtBu, 18 H),
1
1H and 31P{ H} NMR (d in ppm) spectra were recorded using
Varian Mercury Plus spectrometer operating at the appropriate
frequencies using TMS and 85% H3PO4 as internal and external
references, respectively. Microanalyses were performed on a Carlo
Erba Model 1112 elemental analyzer. Mass spectrometry experi-
ments were carried out using Waters Q-Tof micro-YA-105. Melting
points were recorded in capillary tubes and are uncorrected.
1
1.54 (s, NtBu, 18 H). 31P{ H} NMR (162 MHz, CDCl3): d 69.4 (s).
Synthesis of [AuCl{(o-MeOC6H4O)P(l-NtBu)}2] (6). As for 2,
using cis-{(o-MeOC6H4O)P(m-NtBu)}2 (1a) (34.3 mg, 0.076 mmol)
and [AuCl(SMe2)] (22.4 mg, 0.076 mmol). Yield: 87%
(45.3 mg, 0.066 mmol). Mp: 140–142 ◦C. Anal. calcd for
C22H32P2N2O4AuCl: C 38.69, H 4.72, N 4.10. Found: C 38.83,
Syntheses
1
H 4.60, N 4.09. H NMR (400 MHz, CDCl3): d 7.37–6.90 (m,
Synthesis of [Au(SMe2)2]ClO4 (1e). A mixture of [AuCl(SMe2)]
(94.2 mg, 0.319 mmol) and SMe2 (1 mL) in 10 mL dichloromethane
was added dropwise to a dichloromethane (5 mL) suspension of
AgClO4 (72.1 mg, 0.319 mmol) with stirring at room temperature.
The reaction mixture was stirred with minimum light exposure
for 2 h. The precipitated AgCl was removed by filtration through
Celite and the filtrate concentrated to 5 mL and diluted with 5 mL
of Et2O. On standing at -30 ◦C the product formed as a white
crystalline solid. Yield: 90% (120 mg, 0.285 mmol). Mp: 114–
1
Ph, 8 H), 3.86 (s, OMe, 6 H), 1.54 (s, tBu, 18 H). 31P{ H} NMR
(162 MHz, CDCl3): d 129.6 (s), 105.7 (s).
Synthesis of [BrAu{(o-MeOC6H4O)P(l-NtBu)}2AuBr] (7). An
acetonitrile (5 mL) solution of CuBr (28.3 mg, 0.197 mmol)
was added to well-stirred dichloromethane solution (10 mL)
of [ClAu{(o-MeOC6H4O)P(m-NtBu)}2AuCl] (2) (90.3 mg,
0.098 mmol) at room temperature. The colourless reaction mixture
was stirred further for 4 h, concentrated to 7 mL under reduced
pressure and kept at -30 ◦C for two days to afford colourless
crystals of product. Yield: 90% (89.5 mg, 0.089 mmol). Mp: 216–
218 ◦C (dec.). Anal. calcd for C23H33.5Au2Br2N2.5O4P2: C 26.95, H
3.29, N 3.41. Found: C 26.26, H 3.32, N 3.27. 1H NMR (CDCl3,
400 MHz): d 7.26–6.92 (m, Ph, 8 H), 3.90 (s, OMe, 6 H), 1.71 (s,
◦
116 C (dec.). Anal. calcd for C4H12O4S2ClAu: C 11.42, H 2.87,
1
S 15.24. Found: C 11.70, H 2.85, N 15.69. H NMR (400 MHz,
CDCl3): d 2.83 (s, SMe2, 12 H). MS (EI, m/z): 320.84 (M - ClO4).
Synthesis of [ClAu{(o-MeOC6H4O)P(l-NtBu)}2AuCl] (2).
A
dichloromethane (10 mL) solution of [AuCl(SMe2)]
1
tBu, 18 H). 31P{ H} NMR (CDCl3, 162 MHz): d 112.6 (s).
(192 mg, 0.650 mmol) was added dropwise to a well-stirred
dichloromethane solution (15 mL) of cis-{(o-MeOC6H4O)P(m-
NtBu)}2 (1a) (146 mg, 0.325 mmol) at room temperature. The
colourless reaction mixture was stirred further for 4 h with
minimum light exposure. The solvent volume was reduced to
approximately 10 mL under reduced pressure, the solution was
layered with 5 mL of Et2O and on storage at -30 ◦C for a day
an analytically pure crystalline product of 2 formed. Yield: 92%
(274 mg, 0.299 mmol). Mp: 224–226 ◦C (dec.). Anal. calcd for
C22H32N2O4P2Au2Cl2: C 28.86, H 3.52, N 3.06. Found: C 29.04,
Synthesis of [IAu{(o-MeOC6H4O)P(l-NtBu)}2AuI] (8). As
for 7, using CuI (27.8 mg, 0.146 mmol) and [ClAu{(o-
MeOC6H4O)P(m-NtBu)}2AuCl] (2) (66.8 mg, 0.073 mmol). Yield:
88% (70.6 mg, 0.064 mmol). Mp: 212–214 ◦C (dec.). Anal. calcd
for C22H32N2O4P2Au2I2: C 24.06, H 2.93, N 2.55. Found: C 24.12,
1
H 3.05, N 2.47. H NMR (CDCl3, 400 MHz): d 7.31–6.93 (m,
1
Ph, 8 H), 3.91 (s, OMe, 6 H), 1.71 (s, tBu, 18 H). 31P{ H} NMR
(CDCl3, 162 MHz): d 122.6 (s).
Synthesis of [{Au{(o-MeOC6H4O)P(l-NtBu)}2}4](ClO4)4 (9).
1
H 3.38, N 3.36. H NMR (300 MHz, CDCl3): d 7.27–6.92 (m,
A
dichloromethane solution (10 mL) of [Au(SMe2)2]ClO4
Ph, 8 H), 3.89 (s, OMe, 6 H), 1.71 (s, tBu, 18 H). 31P{ H} NMR
1
(71.4 mg, 0.170 mmol) was added dropwise to a well-stirred
dichloromethane solution (10 mL) of cis-{(o-MeOC6H4O)P(m-
NtBu)}2 (1a) (76.5 mg, 0.170 mmol) at room temperature. The
reaction mixture was stirred for 4 h with minimum light exposure,
concentrated to 10 mL under reduced pressure; the solution was
layered with 5 mL of Et2O and stored at -30 ◦C for a day to give the
product as colourless crystals. Yield: 89% (113 mg, 0.037 mmol).
(121 MHz, CDCl3): d 108.1 (s). MS (EI, m/z): 937.21 (M + Na).
Synthesis of [ClAu{(MeOCH2CH2O)P(l-NtBu)}2AuCl] (3).
As for 2, using cis-{(MeOCH2CH2O)P(m-NtBu)}2 (1b) (20.9 mg,
0.059 mmol) and [AuCl(SMe2)] (34.6 mg, 0.118 mmol). Yield:
86% (41.7 mg, 0.051 mmol). Mp: 178–180 ◦C (dec.). Anal. calcd
for C14H32N2O4P2Au2Cl2: C 20.52, H 3.93, N 3.41. Found: C 20.76,
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 5478–5486 | 5479
©

View Article Online
Mp: 188–190 ◦C (dec.). Anal. calcd for C88H128N8O32P8Cl4Au4: C
35.37, H 4.31, N 3.75. Found: C 35.77, H 4.25, N 4.21. 1H NMR
(400 MHz, CDCl3): d 7.26–6.65 (m, Ph, 32 H), 3.70 (s, OMe,
correction as well as a correction for any crystal deterioration
during the data collection (SADABS15). The structures of 4, 6
and 7 were solved by Patterson methods, while 8 and 9 were
solved by direct methods and all were refined by full-matrix
least-squares procedures using the SHELXTL program package.16
Hydrogen atoms were placed in calculated positions (C–H =
t
1
24 H), 1.42 (s, Bu, 72 H). 31P{ H} NMR (162 MHz, CDCl3):
d 127.8 (s).
Synthesis of [Au({(o-MeOC6H4O)P(l-NtBu)}2)2]ClO4 (10).
˚
˚
0.95 A (aromatic rings) or 0.98 A (methyl groups)) and included
as riding contributions with isotropic displacement parameters 1.2
(aromatic rings) or 1.5 (methyl groups) times those of the attached
non-hydrogen atoms.
A
dichloromethane solution (10 mL) of [Au(SMe2)2]ClO4
(29.4 mg, 0.070 mmol) was added dropwise to a well-stirred
dichloromethane solution (10 mL) of cis-{(o-MeOC6H4O)P(m-
NtBu)}2 (1a) (63.2 mg, 0.140 mmol) at room temperature. The
reaction mixture was stirred for 4 h, concentrated to 10 mL under
reduced pressure; the solution was layered with 5 mL of Et2O
and placed at -30 ◦C for a day to afford the product as colourless
crystals. Yield: 82% (68.7 mg, 0.058 mmol). Mp: 148–150 ◦C (dec.).
Anal. calcd for C44H64N4O12P4ClAu: C 44.13, H 5.38, N 4.67.
Found: C 44.28, H 5.61, N 4.39. 1H NMR (400 MHz, CDCl3): d
7.35–6.92 (m, Ph, 16 H), 3.87 (s, OMe, 12 H), 1.46 (s, tBu, 36 H).
For compound 9, one lattice water at full occupancy and two at
half occupancy were located. Also, final difference maps showed
the presence of additional diffuse electron density, likely due to
highly disordered lattice water molecules, which it did not prove
feasible to model so it was removed with the SQUEEZE option of
PLATON.17
1
31P{ H} NMR (162 MHz, CDCl3): d 131.6 (s), 126.6 (s). MS (EI,
Results and discussion
m/z): 1097.40 (M - ClO4).
Synthesis of mono and dinuclear gold complexes
X-Ray crystallography
Addition of two equivalents of [AuCl(SMe2)] to a dichloromethane
solution of the cyclodiphosphazanes cis-{RP(m-NtBu)}2 (1a R =
OC6H4OMe-o, 1b OCH2CH2OMe, 1c NEt2, 1d NHtBu) at room
temperature leads to the formation of dinuclear gold complexes
of the type [AuCl{RP(m-NtBu)}2AuCl] (2–5), respectively. The
mononuclear complex [AuCl{(o-MeOC6H4O)P(m-NtBu)}2] (6)
was isolated from a similar 1 : 1 reaction between 1a and
[AuCl(SMe2)] as shown in Scheme 1. Complexes 2–6 are stable
white solids but are found to be light-sensitive as they turned
from white to a pink color after a week when exposed to
light. The 31P NMR spectra of the dinuclear AuI complexes 2–5
exhibit single resonances at 108.1, 102.3, 73.7 and 69.4 ppm,
respectively, which are considerably shielded compared to those
of the free ligands (1a–1d). Surprisingly, the 31P NMR spectrum
of the complex 6 consists of two single resonances at 129.6 and
Crystals of 4, 6, 7, 8 and 9 were mounted in a CryoLoop with a
drop of Paratone oil and placed in the cold nitrogen stream of the
Kryoflex attachment of the Bruker APEX CCD diffractometer.
For each, a full sphere of data was collected using 606 scans in w
(0.3◦ per scan) at j = 0, 120 and 240◦ (4 and 6) or 3 sets of 400
frames, each of width 0.5◦ in w collected at j = 0.00, 90.00 and
180.00◦ and 2 sets of 800 frames, each of width 0.45◦ in j, collected
at w = -30.00 and 210.00◦. using the SMART software package (8
and 9).13a For 7, the latter protocol was followed under the control
of the APEX2 program package.13b The raw data were reduced to
F2 values using the SAINT+ software14 and a global refinements
of unit cell parameters employing 8337–9918 reflections chosen
from the full data sets were performed. Multiple measurements of
equivalent reflections provided the basis for empirical absorption
Scheme 1
5480 | Dalton Trans., 2009, 5478–5486
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
105.7 ppm, respectively, which are assigned to the uncoordinated
2
and coordinated P-centers of the cyclodiphosphazane; no JPP
coupling was observed. Formation of tri-coordinated T-shaped
AuI complexes of the type [AuX(PR3)2] are well documented.18
Attempts to prepare similar complexes have been unsuccessful and
led to the isolation of only the mononuclear complex 6. However,
cyclodiphosphazanes readily form tri-coordinated CuI complexes
of the type [XCu({(o-MeOC6H4O)P(m-NtBu)}2)2].8c Recently we
observed CuBr and CuI to function as excellent halogen exchange
reagents for the preparation of bromo- and iodo-derivatives
of RhI complexes from the chloro analogs of RhI complexes
containing cyclodiphosphazane.8e Similar reactions between 2 and
CuX (X = Br, I) in 1 : 2 molar ratios afforded the bromo-
and iodo-derivatives [BrAu{(o-MeOC6H4O)P(m-NtBu)}2AuBr]
(7) and [AuI{(o-MeOC6H4O)P(m-NtBu)}2AuI] (8), respectively,
in quantitative yield. The 31P NMR spectra of 7 and 8 consist
of single resonances at 112.6 and 122.6 ppm, respectively. The
31P NMR resonances for [AuX{(o-MeOC6H4O)P(m-NtBu)}2AuX]
show high frequency shift on going from X = Cl to I and the trend
is comparable with those for dppm complexes [CH2{Ph2PAuX}2]
(X = Cl, dP: 24.25; X = Br, dP: 26.8; X = I, dP: 28.0).12,19
Fig. 2 Molecular structure of 6. All hydrogen atoms have been omitted
for clarity.
1
The proposed structures for 2–8 were confirmed by H NMR,
analytical data, mass spectrometry and by single-crystal X-ray
diffraction studies in case of complexes 4, 6, 7 and 8.
Molecular structures of 4, 6, 7 and 8
The molecular structures of 4, 6, 7 and 8 are shown in Fig. 1 to 4,
respectively. Crystallographic information and details of structure
determinations are presented in Table 1.
Fig. 3 (a) Molecular structure of 7. All hydrogen atoms and lattice
solvent have been omitted for clarity. (b) Weak Au ◊ ◊ ◊ Br interaction in
7. Substituents on phosphorus and nitrogen been omitted for clarity.
Fig. 1 Molecular structure of 4. All hydrogen atoms have been omitted
for clarity.
complexes the cyclodiphosphazane ring is slightly puckered as
seen from the dihedral angles between the two PNN planes which
are 13.9(1)◦ (4) and 9.40(9)◦ (6). The intramolecular non-bonding
Lists of important bond distances and bond angles for 4
and 6 are presented in Table 2, while for complexes 7 and 8,
they are presented in Table 3. Crystals of 4 and 6 were grown
from CH2Cl2–Et2O (1 : 1) solution at -30 ◦C. In complex 4
the P1–Au1–Cl1 and P2–Au2–Cl2 bond angles are 174.72(3)◦
and 177.76(3)◦ respectively, whereas in complex 6 the P1–Au–
Cl angle is 176.83(2)◦. These P–Au–Cl bond angles a◦re less linear
compared with that present in (PPh3)AuCl (179.63 ).20 In both
˚
gold–gold distance (Au(1) ◊ ◊ ◊ Au(2)) in complex 4 is 4.830 A, which
indicates the absence of aurophilic interactions.21 In mononuclear
˚
complex 6, the Au–P bond distance (2.210(1) A) is slightly shorter
compared to the same in 4. Perhaps, this change arises due
to the presence of different substituents on phosphorus. In the
molecular structure of 6, the two phenyl groups are arranged in an
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 5478–5486 | 5481
©

View Article Online
Table 1 Crystal data and structural refinement for 4, 6, 7, 8 and 9
4
6
7
8
9
Formula
FW
Crystal system
C16H38Au2Cl2N4P2
C22H32AuClN2O4P2
682.86
Monoclinic
C23H33.5Au2Br2N2.5O4P2
1024.72
Triclinic
¯
P1
C22H32Au2I2N2O4P2
1098.17
Triclinic
¯
P1
C88H128Au4Cl4N8O34.5P8
813.28
Orthorhombic
Pbca
16.954(1)
16.680(1)
17.748(1)
90
90
90
5019.0(6)
8
2.153
12.028
3072
100
2.1–28.3
42 732
6150 [Rint = 0.030]
3027.41
Monoclinic
P21/c
15.963(2)
23.774(2)
33.140(3)
90
107.852(1)
90
11971(2)
4
1.680
5.2
5728
100
2.58–23.29
144 759
17 250 [Rint = 0.031]
Space group
P21/c
˚
a/A
8.713(1)
13.441(7)
22.399(2)
90
90.376(1)
90
2622.7(3)
4
1.729
5.862
1344
100
1.8–28.3
23 002
11.6834(6)
12.5944(6)
21.734(1)
102.171(1)
94.040(1)
105.252(1)
2989.0(3)
4
2.277
12.617
1916
100
9.083(3)
11.593(4)
15.340(1)
84.578(1)
85.850(1)
67.053(1)
1479.4(2)
2
2.465
12.130
1008
100
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
V/A
Z
D
calcd/g cm-3
m(MoKa)/mm-1
F(000)
T/K
2q range/◦
2.1–28.1
52 303
14 439 [Rint = 0.038]
2.3–28.3
26 138
7279 [Rint = 0.031]
Total no. reflections
No. of independent
reflections
6313 [Rint = 0.025]
a
R1
0.0187
0.0427
1.06
0.0193
0.0457
1.04
0.0260
0.0601
1.03
0.0273
0.0672
1.10
0.0366
0.0927
1.04
b
wR2
GOF (F2)
ꢀ
ꢀ
ꢀ
ꢀ
a R = ꢀFo| - |Fcꢀ/ |Fo|. b Rw = {[ w(Fo - Fc2)/ w(Fo2)2]}1/2, w = 1/[s (Fo2)+(xP)2] where P = (Fo + 2Fc2)/3.
2
2
2
◦
˚
Table 2 Selected bond distances (A) and bond angles ( ) for 4 and 6
Bond angles/◦
˚
Bond distances/A
Complex 4
Au1–P1
Au2–P2
Au1–Cl1
Au2–Cl2
P1–N3
P2–N4
P1–N1
P1–N2
P2–N1
P2–N2
2.220(1)
2.222(1)
2.283(1)
2.282(1)
1.634(2)
1.635(2)
1.689(2)
1.710(2)
1.701(2)
1.693(2)
P1–Au1–Cl1
P2–Au2–Cl2
Au1–P1–N3
Au2–P2–N4
Au1–P1–N2
Au2–P2–N2
P1–N1–P2
P1–N2–P2
N1–P1–N2
N1–P2–N2
174.72(3)
177.76(3)
113.48(9)
110.60(9)
117.72(8)
119.07(8)
96.49(11)
95.98(11)
82.73(11)
82.90(10)
Fig. 4 Molecular structure of 8. All hydrogen atoms have been omitted
for clarity.
Complex 6
exo–exo manner with P1–O1–C9 and P2–O2–C16 bond angles
of 122.22(14)◦ and 122.59(15)◦, respectively. In mononuclear
copper complexes [CuX({(o-MeOC6H4O)P(m-NtBu)}2)2] (X = Cl,
Br) the phenyl groups are arranged in an exo–endo fashion
as they do in structurally characterized square planar RhI and
PdII complexes.8a,8b Perhaps the tilting of phenyl groups at the
coordinated phosphorus centers reduces the steric crowding that
arises in trigonal and square planar geometries. In the case of
the gold complexes, the linear geometry does not create such
steric congestion and favours the exo–exo form. The molecules
4 and 6 show weak CH ◊ ◊ ◊ Cl interactions. In molecule 4 a weak
Au–P1
Au–Cl
P1–N1
P1–N2
P2–N1
P2–N2
P1–O1
P2–O2
2.210(1)
2.282(1)
1.665(2)
1.661(2)
1.722(2)
1.719(2)
1.613(2)
1.651(2)
P1–Au–Cl
Au–P1–O1
P1–N1–P2
P1–N2–P2
N1–P1–N2
N1–P2–N2
P1–O1–C9
P2–O2–C16
176.83(2)
112.52(6)
96.82(10)
97.09(9)
84.31(9)
80.90(9)
122.22(14)
122.59(14)
significantly in bond parameters and geometries with the major
difference being the geometry of the exocyclic phenyl substituent
on the phosphorus centers. In the P1P2 ring they are arranged in an
endo–exo fashion whereas in the P3P4 ring the phenyl substituents
are arranged in an exo–exo manner. The dihedral angle between
the P1–N1–N2 and P2–N1–N2 planes is 7.4(2)◦ while that between
the P3–N3–N4 and P4–N3–N4 planes is 6.6(2)◦. In 8, however,
the cyclodiphosphazane ring is planar within experimental error.
All four P–Au–P moieties have distorted linear geometry and
the angles vary from 174.18(3)◦ (P3–Au3–Br3) to 178.34(3)◦
˚
interaction between Cl2 ◊ ◊ ◊ H16_a (2.84 A) exists, whereas the Cl1
centre is free from such non-bonding interactions. Three different
weak CH ◊ ◊ ◊ Cl interactions are found in the mononuclear gold
˚
˚
complex 6, viz. Cl ◊ ◊ ◊ H20_d: 2.73 A, Cl ◊ ◊ ◊ H15C_c: 2.87 A and
Cl ◊ ◊ ◊ H17_b: 2.91 A.
˚
Single crystals of 7 and 8 suitable for diffraction studies were
obtained from a mixture of CH2Cl2–CH3CN at -30 ◦C. There
are two molecules in the asymmetric unit of 7, which differ
5482 | Dalton Trans., 2009, 5478–5486
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
◦
˚
the asymmetric unit and a C41–H41 ◊ ◊ ◊ Br1 (at 2x, 1 - y, 2 - z)
interaction (2.95 A; 147 ).
Table 3 Selected bond distances (A) and bond angles ( ) for 7 and 8
◦
˚
˚
Bond distances/A
Bond angles/◦
Synthesis of cationic AuI complexes
Complex 7
Au1–P1
Au2–P2
Au1–Br1
Au2–Br2
P1–N1
P1–N2
P2–N1
2.210(2)
2.210(2)
2.388(1)
2.387(2)
1.683(4)
1.680(4)
1.686(4)
1.682(4)
2.214(2)
2.219(2)
2.395(1)
2.408(2)
1.699(4)
1.684(4)
1.687(4)
1.670(4)
Br1–Au1–P1
Br2–Au2–P2
Au1–P1–O1
Au2–P2–O3
P1–N1–P2
P1–N2–P2
N1–P1–N2
N1–P2–N2
Br3–Au3–P3
Br4–Au4–P4
Au3–P3–O5
Au4–P4–O7
P3–N3–P4
P3–N4–P4
N3–P3–N4
N3–P4–N4
174.27(3)
178.34(3)
105.56(14)
113.35(13)
95.88(19)
96.15(19)
83.80(18)
83.64(18)
174.18(3)
175.57(3)
113.65(14)
112.84(14)
95.00(19)
96.21(19)
83.78(18)
84.60(18)
The metal precursor [Au(SMe2)2]ClO4 (1e) was prepared from
the equimolar reaction between [AuCl(SMe2)] and AgClO4 in
dichloromethane in the presence of excess SMe2. Compound
1e is a white stable solid and soluble in dichloromethane,
THF and acetone. It undergoes a color change on exposure
to light at room temperature. [Au(SMe2)2]ClO4 can be utilized
to synthesize cationic AuI complexes and has the advantage of
controlling the exact stoichiometry over the in situ generated
cationic gold derivative using silver salts. The 1 : 1 reaction between
cis-{(o-MeOH4C6O)P(m-NtBu)}2 (1a) and [Au(SMe2)2]ClO4 (1e)
affords the tetranuclear AuI macrocycle [Au{(o-MeOC6H4O)P(m-
NtBu)}2](ClO4)4 (9) in good yield (Scheme 2). The 31P NMR
spectrum of 9 shows slightly broad single resonance at 127.8 ppm,
which did not resolve even at low temperature (-30 ◦C).
The mononuclear gold(I) derivative [Au({(o-MeOC6H4O)P(m-
NtBu)}2)2]ClO4 (10) containing monodentate cyclodiphosphazane
was synthesized by reacting two equiv. of 1a with [Au(SMe2)2]ClO4
in dichloromethane. The 31P NMR spectrum of 10 exhibits two
singlet resonances at 131.6 ppm and 126.6 ppm, respectively, for
the uncoordinated and coordinated phosphorus centers. The EI
mass spectrum of 10 shows the base peak at m/z 1097.40, which
corresponds to the [M - ClO4] fragment.
P2–N2
Au3–P3
Au4–P4
Au3–Br3
Au4–Br4
P3–N3
P3–N4
P4–N3
P4–N4
Complex 8
Au1–P1
Au2–P2
Au1–I1
Au2–I2
P1–N1
P1–N2
P2–N1
P2–N2
2.229(2)
2.224(2)
2.562(2)
2.542(1)
1.682(5)
1.675(4)
1.680(4)
1.679(5)
P1–Au1–I1
P2–Au2–I2
Au1–P1–O1
Au2–P2–O3
P2–N1–P1
P1–N2–P2
N2–P1–N1
N2–P2–N1
175.52(3)
174.12(4)
113.95(13)
111.94(15)
96.02(23)
96.31(23)
83.85(22)
83.81(22)
Molecular structure of gold macrocycle
(P2–Au2–Br2). The non-bonded Au ◊ ◊ ◊ Au distances in 7 are
5.414 A and 5.368 A, whereas in the di-iodo derivative 8, the non-
˚
˚
X-Ray quality colourless single crystals of 9 were obtained from
CH2Cl2–Et2O solution at -30 ◦C. The molecular structure of 9
with the atom numbering scheme is shown in Fig. 5 while selected
bond distances and bond angles are listed in Table 4. The core
structure of 9 consists of four cyclodiphosphazanes connected
via four di-coordinated gold centers to form a tetranuclear gold
macrocycle with a cavity space of 7.932 A (Au1 ◊ ◊ ◊ Au3) ¥ 7.311 A
(Au2 ◊ ◊ ◊ Au4). In molecule 9, the gold centers are in distorted linear
geometry with P–Au–P bonds angles varying from 175.69(7)◦
(P4–Au3–P5) to 177.33(7)◦ (P1–Au1–P8). The average Au–P bond
˚
˚
bonded Au1 ◊ ◊ ◊ Au2 separation is 5.660 A, which is 0.830 A longer
than that in the di-chloro derivative 4. In the crystal structure of 7,
two weak Au ◊ ◊ ◊ Br interactions22 exist between two independent
˚
˚
molecules (Au4 ◊ ◊ ◊ Br2 = 3.443 A and Au1 ◊ ◊ ◊ Br4 = 3.435 A),
which leads to the formation of an eight membered ring containing
three AuI centers as depicted in Fig. 3b. In addition, there
˚
˚
˚
is weak C–H ◊ ◊ ◊ O hydrogen bond (C46a–H46a ◊ ◊ ◊ O2: 2.60 A;
161◦) and a C–H ◊ ◊ ◊ p interaction (◦C39–H39 ◊ ◊ ◊ centroid of the
˚
C9–C14 aromatic ring: 2.80 A; 157 ) between the molecules in
Scheme 2
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 5478–5486 | 5483
©

View Article Online
Fig. 5 (a) Molecular structure of 9. For clarity, hydrogen atoms, substituents on phosphorus and nitrogen, three perchlorate anions and solvent molecules
have been omitted. (b) Space filling model showing the macrocycle and encapsulated perchlorate anion. (c) Bowl shaped macrocycle 9.
˚
˚
distance in 9 is 2.291(2) A, which is longer than the Au–P bond
Similarly, the N3 ◊ ◊ ◊ N7 and N4 ◊ ◊ ◊ N8 distances are 9.905 A and
˚
present in the gold halo derivatives of the same ligand (6–8) and
which may be due to the trans influence of mutually trans-oriented
phosphorus atoms. These Au–P bond distances are in good
agreement with those in the similar dinuclear complex [Au2{m-
PhN(P(OC6H4OMe-o)2)2}](OTf)2.23 Wright and co-workers have
reported tetra- and pentameric cyclodiphosphazane macrocycles
of the type [{P(m-NtBu)}2NH]n (n = 4, 5), in which all the
four cyclodiphosphazanes and NH are arranged almost in the
same plane.1h,4 In contrast, in macrocycle 9, two P2N2 rings are
present above the 12 atom {Au-(P ◊ ◊ ◊ P)}4 mean plane while other
alternate pair of P2N2 units lie below the mean plane. This unusual
geometrical arrangement of cyclodiphosphazane units in 9 confers
a ‘bowl’ or ‘boat’ shape to the macrocycle as shown in Fig. 5b. In
macrocycle 9, the distances between two opposite nitrogen centers
7.590 A, respectively. These uneven N ◊ ◊ ◊ N separations indicate
that the P2N2 rings are not arranged parallel whereas in [{P(m-
NtBu)}2NH]4 the distances between opposite pairs of nitrogen
centers are almost equal. Interestingly, one of the perchlorate
anions is present inside the macrocyclic cavity while the other
three perchlorate anions are on the periphery of the macrocycle.
The perchlorate ion present inside the cavity is one of the rare
examples of host–guest systems with gold macrocycles and is
held through a combination of weak O ◊ ◊ ◊ Au (Table 4) and
C–H ◊ ◊ ◊ Au interactions.22 The latter range from 2.32 to 2.58 A
˚
and involve one hydrogen on each of two methyl groups from the
t-butyl groups bound to N2, N3, N5 and N7. The encapsulated
perchlorate ion is displaced away from the center of the cavity as
indicated by the Au1 ◊ ◊ ◊ O17 and Au1 ◊ ◊ ◊ O18 distances (3.417(3)
˚
˚
˚
in the same plane are 9.230 A (N1 ◊ ◊ ◊ N6) and 6.902 A (N2 ◊ ◊ ◊ N5).
and 3.263(3) A), which are significantly longer than those in
5484 | Dalton Trans., 2009, 5478–5486
This journal is
The Royal Society of Chemistry 2009
©

View Article Online
◦
˚
host–guest properties with other anions and also to synthesize
the macrocycles of varied size is in progress.
Table 4 Selected bond distances (A) and bond angles ( ) for 9
˚
Bond distances/A
Bond angles/◦
Acknowledgements
Au1–P1
Au1–P8
Au2–P2
Au2–P3
Au3–P4
Au3–P5
Au4–P6
Au4–P7
P1–N1
P1–N2
P2–N1
P2–N2
P3–N3
P3–N4
P4–N3
P4–N4
P5–N5
P5–N6
P6–N5
P6–N6
P7–N7
2.297(2)
2.293(2)
2.288(2)
2.273(2)
2.295(2)
2.305(2)
2.294(2)
2.280(2)
1.682(7)
1.680(6)
1.673(6)
1.680(7)
1.678(6)
1.682(6)
1.675(6)
1.686(5)
1.658(6)
1.679(6)
1.677(5)
1.675(6)
1.681(7)
1.682(5)
1.668(5)
1.690(7)
1.443(7)
1.429(6)
1.436(5)
1.437(5)
3.073(3)
3.006(3)
3.034(3)
3.100(3)
3.176(3)
P1–Au1–P8
P2–Au2–P3
P4–Au3–P5
P6–Au4–P7
N1–P1–N2
N1–P2–N2
P1–N1–P2
P1–N2–P2
N3–P3–N4
N3–P4–N4
P3–N3–P4
P3–N4–P4
N5–P5–N6
N5–P6–N6
P5–N5–P6
P5–N6–P6
N7–P7–N8
N7–P8–N8
P7–N7–P8
177.33(7)
175.99(7)
175.69(7)
175.75(7)
84.06(29)
84.33(29)
95.84(28)
95.67(28)
84.49(28)
84.48(28)
95.53(28)
94.99(27)
84.27(27)
83.80(27)
96.28(27)
95.57(28)
84.07(28)
84.22(28)
95.92(28)
95.08(27)
109.63
We are grateful to the Department of Science and Technology
(DST), New Delhi for funding through grant SR/S1/IC-02/007.
PC thanks CSIR for Research Fellowship. JTM thanks the
Louisiana Board of Regents and the Chemistry Department of
Tulane University for support of the X-ray laboratory.
References
1 (a) M. S. Balakrishna, D. J. Eisler and T. Chivers, Chem. Soc. Rev.,
2007, 36, 650–664; (b) P. Kommana and K. C. Kumara Swamy, Inorg.
Chem., 2000, 39, 4384–4385; (c) F. Garcia, J. M. Goodman, R. A.
Kowenicki, M. McPartlin, L. Riera, M. A. Silva, A. Wising and D. S.
Wright, Dalton Trans., 2005, 1764–1773; (d) A. Bashall, E. L. Doyle, C.
Tubb, S. J. Kidd, M. McPartlin, A. D. Woods and D. S. Wright, Chem.
Commun., 2001, 2542–2543; (e) P. Chandrasekaran, J. T. Mague and
M. S. Balakrishna, Inorg. Chem., 2009, 48, 1398–1406.
2 (a) M. Chakravarty, P. Kommana and K. C. Kumara Swamy, Chem.
Commun., 2005, 5396–5398; (b) J. K. Brask, T. Chivers, M. L. Krahn
and M. Parvez, Inorg. Chem., 1999, 38, 290–295; (c) D. Dou, E. N.
Duesler and R. T. Paine, Inorg. Chem., 1999, 38, 788–793; (d) F.
Garc´ıa, R. A. Kowenicki, I. Kuzu, L. Riera, M. McPartlin and
D. S. Wright, Dalton Trans., 2004, 2904–2909; (e) F. Dodds, F.
Garcia, R. A. Kowenicki, M. McPartlin, A. Steiner and D. S. Wright,
Chem. Commun., 2005, 3733–3735; (f) F. Dodds, F. Garcia, R. A.
Kowenicki, M. McPartlin, L. Riera, A. Steiner and D. S. Wright, Chem.
Commun., 2005, 5041–5043; (g) M. S. Balakrishna and J. T. Mague,
Organometallics, 2007, 26, 4677–4679.
P7–N8–P8
O17–Cl1–O18
O18–Cl1–O19
O19–Cl1–O20
O17–Cl1–O20
Au1–P1–O1
Au2–P2–O3
Au3–P4–O7
Au4–P7–O13
Au2 ◊ ◊ ◊ O18–Cl1
Au2 ◊ ◊ ◊ O19–Cl1
Au4 ◊ ◊ ◊ O17–Cl1
Au4 ◊ ◊ ◊ O20–Cl1
Au3 ◊ ◊ ◊ O20–Cl1
P7–N8
P8–N7
P8–N8
108.73
108.60
108.90
Cl1–O17
Cl1–O18
Cl1–O19
Cl1–O20
Au2 ◊ ◊ ◊ O18
Au2 ◊ ◊ ◊ O19
Au4 ◊ ◊ ◊ O17
Au4 ◊ ◊ ◊ O20
Au3 ◊ ◊ ◊ O20
114.55(20)
110.77(19)
118.19(23)
107.4(2)
101.47(9)
104.39(9)
104.47(9)
101.72(9)
113.39(9)
3 (a) E. L. Doyle, L. Riera and D. S. Wright, Eur. J. Inorg. Chem., 2003,
3279–3289; (b) Ke Zhang, J. Prabhavathy, John H. K. Yip, Lip Lin Koh,
Geok Kheng Tan and Jagadese J. Vittal, J. Am. Chem. Soc., 2003, 125,
8452–8453; (c) J. H. K. Yip and J. Prabhavathy, Angew. Chem., Int. Ed.,
2001, 40, 2159–2162.
Table 4. Another example of perchlorate ion encapsulation occurs
in the tri-gold macrocyclic complex [Au3(PanP)3](ClO4)3 (PanP =
9,10-bis(diphenylphosphino)anthracene)3b but here three of the
oxygen atoms of the encapsulated ion are directed towards the
centers of the anthracene moieties and the ion resides in the center
of the cavity. All four P2N2 rings are slightly puckered as seen
from the dihedral angles between the two PNN planes in each unit
(for P1P2 ring, 3.4(3)◦; P3P4 ring, 7.3(3)◦; P5P6 ring, 2.8(3)◦; P7P8
ring, 8.6(3)◦). The exocyclic phenyl substituents on phosphorus are
oriented in an exo–exo manner in the P1P2 and P5P6 positions,
whereas in the P3P4 and P7P8 positions they are arranged in an
exo–endo orientation.
`
4 (a) A. Bashall, A. D. Bond, E. L. Doyle, F. GarcIa, S. Kidd, G. T.
Lawson, M. C. Parry, M. McPartlin, A. D. Woods and D. S. Wright,
Chem.–Eur. J., 2002, 8, 3377–3385; (b) F. Garcia, J. M. Goodman, R. A.
Kowenicki, I. Kuzu, M. McPartlin, M. A. Silva, L. Riera, A. D. Woods
and D. S. Wright, Chem.–Eur. J., 2004, 10, 6066–6072.
5 (a) J. L. Sessler, P. A. Gale, W.-S. Cho, Anion Receptor Chemistry,
Royal Society of Chemistry, Cambridge 2006; (b) F. P. Schmidtchen
and M. Berger, Chem. Rev., 1997, 97, 1609–1646; (c) P. D. Beer and
P. A. Gale, Angew. Chem., Int. Ed., 2001, 40, 486–516; (d) C. Suksai
and T. Tuntulani, Chem. Soc. Rev., 2003, 32, 192–202; (e) H. Maeda, Y.
Haketa and T. Nakanishi, J. Am. Chem. Soc., 2007, 129, 13661–13674.
6 (a) V. Amendola, M. Bonizzoni, D. Esteban-Gomez, L. Fabbrizzi,
M. Licchelli, F. Sancenon and A. Taglietti, Coord. Chem. Rev., 2006,
250, 1451–1470; (b) P. A. Gale, S. E. Garcia-Garrido and J. Garric,
Chem. Soc. Rev., 2008, 37, 151–190; (c) C. R. Bondy and S. J. Loeb,
Coord. Chem. Rev., 2003, 240, 77–99; (d) J. M. Llinares, D. Powell and
K. Bowman-James, Coord. Chem. Rev., 2003, 240, 57–75; (e) T. W.
Hudnall, Y.-M. Kim, M. Bebbington, D. Bourissou and F. P. Gabba¨ı,
J. Am. Chem. Soc., 2008, 130, 10890–10891; (f) T. J. Wedge and M. F.
Hawthorne, Coord. Chem. Rev., 2003, 240, 111–128.
7 (a) C. R. Rice, Coord. Chem. Rev., 2006, 250, 3190–3199; (b) P. D. Beer
and E. J. Hayes, Coord. Chem. Rev., 2003, 240, 167–189; (c) C. R. Bondy,
P. A. Gale and S. J. Loeb, J. Am. Chem. Soc., 2004, 126, 5030–5031.
8 (a) P. Chandrasekaran, J. T. Mague and M. S. Balakrishna,
Organometallics, 2005, 24, 3780–3783; (b) P. Chandrasekaran, J. T.
Mague and M. S. Balakrishna, Inorg. Chem., 2005, 44, 7925–7932; (c) P.
Chandrasekaran, J. T. Mague and M. S. Balakrishna, Inorg. Chem.,
2006, 45, 6678–6683; (d) P. Chandrasekaran, J. T. Mague and M. S.
Balakrishna, Dalton Trans., 2007, 2957–2962; (e) P. Chandrasekaran,
J. T. Mague, R. Venkateswaran and M. S. Balakrishna, Eur. J. Inorg.
Chem., 2007, 4988–4997; (f) P. Chandrasekaran, J. T. Mague and
M. S. Balakrishna, Polyhedron, 2008, 27, 80–86; (g) D. Suresh, M. S.
Balakrishna and J. T. Mague, Dalton Trans., 2008, 3272–3274; (h) D.
Suresh, M. S. Balakrishna and J. T. Mague, Dalton Trans., 2008, 2812–
2814; (i) M. S. Balakrishna, R. Venkateswaran and J. T. Mague, Inorg.
Conclusions
Mono and dinuclear gold(I) complexes of cyclodiphosphazanes
were selectively prepared by controlling the reaction stoichiometry.
CuBr and CuI act as efficient halogen exchange reagents for the
conversion of chloro derivatives of the dinuclear gold complex into
the corresponding bromo and iodo derivatives. The rigid planar
nature of the cyclodiphosphazane and linear di-coordination of
gold(I) center favours the formation of a tetranuclear metalla-
macrocycle, whereas tri- and/or tetracoordination of copper(I)
and silver(I) centers leads to the formation of one dimensional
metallopolymers. The tetranuclear gold macrocycle acts as a
host for the perchlorate anion with stabilization via Au ◊ ◊ ◊ O
interactions. This is a rare example of gold metalla-macrocycles
showing anion encapsulation. Further work to explore its
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 5478–5486 | 5485
©

View Article Online
Chem., 2009, 47, 1398–1406; (j) D. Suresh, M. S. Balakrishna and J. T.
Mague, Tetrahedron Lett., 2007, 48, 2283–2285; (k) P. Chandrasekaran,
M. S. Balakrishna and J. T. Mague, Tetrahedron Lett., 2007, 48, 2733–
2734.
16 (a) SHELXTL, Version 6.10Bruker-AXS, Madison, WI, 2000; (b) G. M.
Sheldrick, SHELXS-97 and SHELXL-97University of Gottingen,
Gottingen, Germany, 1997.
17 A. L. Spek, PLATON, A Multipurpose Crystallographic Tool, Utrecht
9 W. L. F. Armarego and D. D. Perrin, Purification of Laboratory
Chemicals, 4th edn, Butterworth-Heinemann, Oxford, UK, 2000.
10 R. Keat, D. S. Rycroft and D. G. Thompson, J. Chem. Soc., Dalton
Trans., 1980, 321–326.
University, Utrecht, The Netherlands, 2007.
18 P. Sinha, A. K. Wilson and M. A. Omary, J. Am. Chem. Soc., 2005,
127, 12488–12489.
19 (a) D. Schneider, A. Schier and H. Schmidbaur, Dalton Trans., 2004,
1995–2005; (b) M. Bardaj´ı, P. G. Jones, A. Laguna, M. D. Villacampa
and N. Villaverde, Dalton Trans., 2003, 4529–4536.
20 N. C. Baenziger, W. E. Bennett and D. M. Soboroff, Acta Crys-
tallogr., Sect. B: Struct. Crystallogr. Cryst. Chem., 1976, 32, 962–
963.
21 P. Pyykko, Chem. Rev., 1997, 97, 597–636.
22 A. Bondi, J. Phys. Chem., 1964, 68, 441–451.
23 C. Ganesamoorthy, M. S. Balakrishna, J. T. Mague and H. M.
Tuononen, Inorg. Chem., 2008, 47, 2764–2776.
11 I. Schranz, L. Stahl and R. J. Staples, Inorg. Chem., 1998, 37, 1493–
1498.
12 M.-C. Brandys, M. C. Jennings and R. J. Puddephatt, J. Chem. Soc.,
Dalton Trans., 2000, 4601–4606.
13 (a) SMART, Version 5.625,Bruker-AXS, Madison, WI, 2000;
(b) APEX2, Version 2.1-0, Bruker-AXS, Madison, WI, 2006.
14 SAINT+, Version 6.35A, Bruker-AXS, Madison, WI, 2002.
15 G. M. Sheldrick, SADABS, Version 2.05, University of Go¨ttingen,
Go¨ttingen, Germany, 2002.
5486 | Dalton Trans., 2009, 5478–5486
This journal is
The Royal Society of Chemistry 2009
©