Group 11 complexes with the bidentate di(1H-indazol-1-yl)methane and di(2H-indazol-2-yl)methane) ligands

Article abstract of DOI:10.1039/c3ce40355f

Twenty-four new copper, silver and gold complexes based on a bis(pyrazolyl)methane ligand L (in detail L = L¹, di(1H-indazol-1-yl)methane; L = L², di(2H-indazol-2-yl)methane) are prepared. The [Cu(L)(PR₃)₂]X species have been obtained from the reaction of [CuX(PR₃)₂] with L upon the displacement of X from the copper coordination sphere. 1:1 [CuX₂(L)] complexes were obtained when L¹ reacts with CuX₂ whereas under the same conditions, L² gave the ionic species [CuX(L) ₂]X. When L¹ reacts with CuCl₂, however, the dinuclear [CuCl₂(L¹)]₂ complex is formed which, upon treatment with dimethylformamide (DMF), gave the mononuclear derivative [CuCl₂(L¹)(DMF)]. L¹ and L² often show a different reactivity toward silver salts. For example, in the reaction with AgNO₃, the ionic compound [Ag(L¹)₂]NO ₃ is obtained when L¹ is used as a starting reagent and the neutral 1:2 adduct [AgONO₂(κ-L²) (κ²-L²)] containing a mono and a bidentate ligand is formed when L² is employed as a ligand. L¹ gave 2:1 adducts with AgCX₃SO₃ (X = H or F) and AgClO₄, whereas 1:1 adducts are formed under the same conditions with L². L¹ and L² give analogous dinuclear ([Ag(O ₂CCF₃)(L)]₂) and mononuclear ionic species ([Ag(L)₂]BF₄) when they react with Ag(O ₂CCF₃) and AgBF₄ species. Two analogous gold(iii) complexes [AuCl₂(L)][AuCl₄] have also been obtained in the reaction of L with AuCl₃ when the reaction was carried out in an excess of the ligands. All the air- and thermally stable complexes have been characterized by analytical and spectral (IR, conductivity, ESI-MS, ¹H and ¹³C NMR solution data) methods.

Full text of DOI:10.1039/c3ce40355f

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Group 11 complexes with the bidentate di(1H-indazol-
1-yl)methane and di(2H-indazol-2-yl)methane) ligands3
Cite this: CrystEngComm, 2013, 15,
3892
Claudio Pettinari,*a Fabio Marchetti,b Serena Orbisaglia,b Riccardo Pettinari,a
d
d
d
Jean Ngoune,ac Margarita Gomez, Carina Santos and Eleuterio Alvarez*
´
´
Twenty-four new copper, silver and gold complexes based on a bis(pyrazolyl)methane ligand L (in detail L
= L1, di(1H-indazol-1-yl)methane; L = L2, di(2H-indazol-2-yl)methane) are prepared. The [Cu(L)(PR3)2]X
species have been obtained from the reaction of [CuX(PR3)2] with L upon the displacement of X from the
copper coordination sphere. 1 : 1 [CuX2(L)] complexes were obtained when L1 reacts with CuX2 whereas
under the same conditions, L2 gave the ionic species [CuX(L)2]X. When L1 reacts with CuCl2, however, the
dinuclear [CuCl2(L1)]2 complex is formed which, upon treatment with dimethylformamide (DMF), gave the
mononuclear derivative [CuCl2(L1)(DMF)]. L1 and L2 often show a different reactivity toward silver salts. For
example, in the reaction with AgNO3, the ionic compound [Ag(L1)2]NO3 is obtained when L1 is used as a
starting reagent and the neutral 1 : 2 adduct [AgONO2(k-L2)(k2-L2)] containing a mono and a bidentate
ligand is formed when L2 is employed as a ligand. L1 gave 2 : 1 adducts with AgCX3SO3 (X = H or F) and
AgClO4, whereas 1 : 1 adducts are formed under the same conditions with L2. L1 and L2 give analogous
dinuclear ([Ag(O2CCF3)(L)]2) and mononuclear ionic species ([Ag(L)2]BF4) when they react with Ag(O2CCF3)
and AgBF4 species. Two analogous gold(III) complexes [AuCl2(L)][AuCl4] have also been obtained in the
reaction of L with AuCl3 when the reaction was carried out in an excess of the ligands. All the air- and
thermally stable complexes have been characterized by analytical and spectral (IR, conductivity, ESI-MS, 1H
and 13C NMR solution data) methods.
Received 26th February 2013,
Accepted 6th March 2013
DOI: 10.1039/c3ce40355f
www.rsc.org/crystengcomm
The bis(pyrazol-1-yl)alkanes, (R2C)n(pzx)2, in particular dis-
play a coordinating behavior which is often very different from
Introduction
Poly(pyrazol-1-yl)alkanes are a family of multidentate ligands
that have recently received increasing attention due to their
high flexibility and chemical stability.1 These molecules are
able to afford several types of stable metal derivatives,
providing fine control of the spectroscopic and electronic
properties of the discrete and polynuclear metal complexes.2
They have, however, been less investigated than the corre-
sponding poly(pyrazol-1-yl)borates.3 Furthermore, recently the
possibility to functionalize them by introducing donating
groups on the bridging carbon4 has widely expanded their use
in coordination chemistry.5
that shown by other chelating N2-donor ligands. The main
difference from bipy (2,29-bipyridyl) or phen (1,10-phenanthro-
line) metal adducts, that generally contain an approximately
planar five membered –M–N–C–C–N moiety,6 stems from the
boat conformation of the six-membered cycle formed by
bis(azolyl)alkanes upon coordination. Moreover, bis(pyrazoly-
l)alkanes offer the possibility of modulating the steric and
electronic properties by introducing substituents not only in
the pyrazole rings but also at the central carbon atom. For
example, Reger et al.7 have expanded this field by using
bis(pyrazol-1-yl) fragments in conjunction with several brid-
ging spacers to generate ‘‘third-generation’’ flexible di- and
polytopic ligands able to afford complexes of several d-block
metal acceptors with different nuclearity and unusual mag-
netic properties.
Another leading motif in the last few years has been the
substitution of the pyrazole ring with other azoles, such as
triazoles8 and imidazoles.9 In this respect, we have reported
the synthesis and the coordination properties of the bis(1,2,4-
triazol-1-yl)alkane ligand which is capable of coordinating
silver, cobalt, nickel, copper and cadmium salts through the
exodentate nitrogen atoms at the 4-positions of the triazole
rings, yielding bi- and three-dimensional polymers.8
aSchool of Pharmacy, University of Camerino, Via S. Agostino 1, 62032 Camerino
MC, Italy. E-mail: claudio.pettinari@unicam.it; Fax: +39 0737 637345;
Tel: +39 0737 402848
bSchool of Science and Technology, University of Camerino, Via S. Agostino 1, 62032
Camerino MC, Italy. E-mail: fabio.marchetti@unicam.it; Fax: +39 0737 637345;
Tel: +39 0737 402217
cDepartment of Chemistry, University of Dschang, PO Box 67, Dschang, Cameroon
d
´
Instituto de Investigaciones Quımicas (IIQ), Consejo Superior de Investigaciones
´
´
Cientıficas (CSIC), Universidad de Sevilla (US), Avda. Americo Vespucio 49, Isla de La
Cartuja, 41092 Sevilla, Spain. E-mail: ealvarez@iiq.csic.es; Fax: +34 954 460 565;
Tel: +34 954 489 560
CCDC 917666–917680. For crystallographic data in CIF or other electronic
3
format see DOI: 10.1039/c3ce40355f
3892 | CrystEngComm, 2013, 15, 3892–3907
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at room temperature (400 MHz for 1H and 100 MHz for 13C) or
1
on a Bruker DRX-500 spectrometer (500 MHz for H and 125
MHz for 13C, IIQ). H and C chemical shifts (d) are reported in
parts per million (ppm) from SiMe4 (1H and 13C calibration by
an internal deuterium solvent lock). Peak multiplicities are
abbreviated: singlet, s; doublet, d; triplet, t; quartet, q; and
multiplet, m. Electrospray mass spectra (ESIMS) were obtained
using a Series 1100 MSI detector HP spectrometer or a Bruker
Esquire6000 instrument (IIQ). Melting points are uncorrected
and were taken on an SMP3 Stuart scientific instrument and
on a capillary apparatus. The electrical conductivity measure-
ments (LM, reported as S cm2 mol21) of acetonitrile and water
solutions of the complexes were taken with a Crison CDTM
522 conductimeter at room temperature.
Chart 1
Additionally, we have also described
a bis(imidazol-1-
yl)methane ligand able to afford novel polynuclear species
based on Sn, Zn, Cd and Hg.9 Very recently, we have replaced
the pyrazolyl with indazolyl rings and explored the coordina-
tion chemistry of the regioisomeric bis(indazol-1-yl)alkane
ligands (Chart 1) toward zinc, cadmium and mercury.10 We
have recently been interested in the silver, gold and copper
coordination chemistry of pyrazole-type ligands as it has been
recently reported that selected coinage metal complexes
containing chelating N2-donor ligands show relevant biologi-
cal properties and are currently applied as antibacterial agents
in therapeutic protocols.11 In spite of their potent antimicro-
bial properties and low human toxicity, for example, silver
complexes have been used in a variety of applications, like
water purification, wound management, eye-drops, anti-
infective coatings in medical devices and in burn treatments.12
Here, we extend our investigation into the synthesis and full
characterization of silver, copper and gold derivatives contain-
ing the two regioisomers depicted in Chart 1, chosen because
they provide a different steric hindrance and basicity with
respect to previously investigated bis(pyrazolyl)methanes and
could significantly modify both the structural and spectro-
scopic properties of the formed complexes.
Synthesis of [Cu(L1)(Cy3P)2]ClO4 (1)
Di(1H-indazol-1-yl)methane (L1) (0.0248 g, 0.1 mmol) was
progressively added to a solution of [CuClO4(Cy3P)2] (0.0724 g,
0.1 mmol) in CH3CN (20 mL) . The colorless solution was
stirred at room temperature overnight. By slow evaporation of
the solvent, a colorless powder was afforded in a 67% yield,
which was identified as derivative 1. It is soluble in alcohols,
acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C51H78ClCuN4O4P2: C, 63.01; H, 8.09; N, 5.76. Found: C,
62.65; H, 8.08; N, 6.06. Mp. 138–140 uC. IR (cm21): 3118w n(C–
Haromatic), 2922w, 2848m n(C–Haliphatic), 1618w, 1499m n(CLN +
CLC), 1463w, 1445m, 1417m, 1297w, 1280m, 1197m, 1176m,
1095vs br n(ClO4), 1026m, 1005m, 934w, 909m, 888m, 850m,
1
828w, 758w, 745m, 736m. H NMR (CD3CN): d 1.35 (m), 1.85
(m) (33H, Cy3P), 6.95 (s, 2H, CH2), 7.19 (t, 2H, H6), 7.46 (t, 2H,
H7), 7.74 (d, 2H, H5), 7.87 (d, 2H, H8), 8.02 (s, 2H, H3).
2
13C{1H}NMR (CD3CN): d 28.15 (d, C2, Cy, J(13C–31P): 10 Hz),
31.15 (C4, Cy), 32.88 (d, C3, Cy, 3J(13C–31P): 16 Hz), 34.89 (d, C1,
Cy, 1J(13C–31P): 59 Hz), 61.14 (C1), 110.94 (C8), 122.23 (C5),
122.68 (C6), 125.32 (C4), 128.37 (C7), 135.98 (C3), 140.44 (C9).
31P NMR (CD3CN, 20 uC): 15.80br, 57.65br. 31P NMR (CD3CN,
240 uC): 10.83s, 15.58br, 58.20br. ESI MS (+, CH3CN): 623 [100]
Experimental
[Cu(Cy3P)2]+. LM (CH3CN, 1 6 1023 M) = 144 S cm2 mol21
.
All chemicals were purchased from Aldrich (Milwaukee, WI)
and used as received. Ligands L1 and L2 were prepared by
following the procedure described by ref. 10. All the reactions
and manipulations were performed under a dry nitrogen
atmosphere and solvents were degassed prior to use. However,
the reactions can also be performed in air but the products will
invariably contain one or two water molecules, likely dispersed
in the solid lattice, as observed in the crystallographic studies
(see below) carried out on single crystals of one derivative,
obtained from the slow evaporation of chloroform solutions
performed in air. Solvent evaporations were always carried out
under vacuum using a rotary evaporator. The samples for
microanalysis were dried in vacuo to constant weight (20 uC, ca.
0.1 Torr). Elemental analyses (C, H, N, S) were performed in-
house with a Fison Instrument 1108 CHNS-O Elemental
analyzer or with a LECO-TruSpec CHN/CHNS apparatus (IIQ).
IR spectra were recorded from 4000 to 200 cm21 with a Perkin-
Elmer System 2000 FT-IR instrument or with a Bruker Vector
22 spectrometer (IIQ). 1H and 13C{1H}NMR spectra were
recorded on a 400 Mercury Plus Varian instrument operating
Synthesis of [Cu(L2)(Cy3P)2]ClO4 (2)
Derivative 2 was prepared by following a similar procedure to
that reported for 1 using [CuClO4(Cy3P)2] (0.0724 g, 0.1 mmol)
and di(2H-indazol-2-yl)methane (L2) (0.0248 g, 0.1 mmol) in
CH3CN (20 mL). Yield 69%. It is soluble in alcohols,
acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C51H78ClCuN4O4P2: C, 63.01; H, 8.09; N, 5.76. Found: C,
62.67; H, 8.05; N, 5.97. Mp. 160–162 uC. IR (cm21): 3130w n(C–
Haromatic), 2918w, 2848m n(C–Haliphatic), 1631w, 1517m n(CLN +
CLC), 1468w, 1446m, 1414w, 1373w, 1329w, 1288w, 1264w,
1174m, 1080vs br n(ClO4), 1004m, 890w, 846w, 814w, 757m,
744m, 703w. 1H NMR (CD3CN): d 1.35 (m), 1.85 (m) (33H,
Cy3P), 6.90 (s, 2H, CH2), 7.12 (t, 2H, H6), 7.33 (t, 2H, H5), 7.65
(d, 2H, H7), 7.75 (d, 2H, H4), 8.49 (s, 2H, H9). 13C{1H}NMR
(CD3CN): d 28.14 (br, C2, Cy), 31.16 (br, C4, Cy), 32.21 (br, C3,
Cy), 35.73 (d, C1, Cy, 1J(13C–31P): 61 Hz), 67.80 (C1), 118.37 (C4),
122.22 (C7), 122.65 (C6), 123.51 (C9), 126.45 (C8), 128.58 (C5),
149.77 (C3). 31P NMR (CD3CN, 20 uC): 13.76br, 52.31br. 31P
NMR (CD3CN, 240 uC): 10.46s, 14.40s, 52.91s. ESI MS (+,
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CH3CN): 623 [100] [Cu(Cy3P)2]+. LM (CH3CN, 1 6 1023 M) =
for C15H12CuN6O6: C, 41.34; H, 2.78; N, 19.28%. Found: C,
41.97; H, 2.93; N, 18.83%. Mp. 165 uC. IR (cm21): 3119w,
3067w, 3015w n(C–Haromatic), 2968w, 2924w n(C–Haliphatic),
1746w n(NO3), 1716w n(NO3), 1622m n(CLN + CLC), 1465s br
n(NO3), 1400m, 1382m, 1367w, 1285s br n(NO3), 1263s br
n(NO3), 1225m, 1195m, 1181m, 1159m, 1129w, 1091w, 1005m,
983m, 952w, 911m, 873w, 843w, 824w, 806w, 782m, 743s br
n(NO3). ESI MS (+, CH3CN): 559 [100] [Cu(L1)2]+, 373 [20]
[Cu(NO3)L1]+, 352 [70] [Cu(CH3CN)(L1)]+. LM (CH3CN, 1 6
167 S cm2 mol21
.
Synthesis of [Cu(L1)(Ph3P)2]NO3 (3)
Derivative 3 was prepared by following a similar procedure to
that reported for 1 using a CH3CN solution (10 mL) of
[Cu(NO3)(PPh3)2] (0.0687 g, 0.1 mmol) and an EtOH solution
(10 mL) of di(1H-indazol-1-yl)methane (L1) (0.0248 g, 0.1
mmol). Yield 85%. It is soluble in alcohols, chlorinated
solvents, acetonitrile, acetone, DMSO and DMF. Anal. calc.
for C51H42CuN5O3P2: C, 68.18; H, 4.71; N, 7.80. Found: C,
67.97; H, 4.64; N, 7.44. Mp. 101–102 uC. IR (cm21): 3060w n(C–
Haromatic), 2973w, 2945w n(C–Haliphatic), 1620m, 1507m n(CLN +
CLC), 1479m, 1465m, 1435s, 1336m, 1318m, 1284m, 1266m,
1220w, 1172m, 1128w, 1118w, 1093m, 1049w, 1036w, 1027w,
999w, 951w, 910w, 880w, 835w, 769w, 745s, 694s. 1H NMR
(CD3CN): d 6.94 (s, 2H, CH2), 7.19 (t, 2H, H6), 7.25–7.44 (m,
30H, Ph), 7.47 (t, 2H, H7), 7.72 (d, 2H, H5), 7.89 (d, 2H, H8),
8.01 (s, 2H, H3). 13C{1H}NMR (CD3CN): d 61.56 (C1), 111.04
(C8), 122.09 (C5), 122.49 (C6), 125.47 (C4), 128.04 (C7), 129.93
1023 M) = 56 S cm2 mol21
.
Synthesis of [CuNO3(L2)2]NO3?H2O (6)
Derivative 6 was prepared by following a similar procedure to
that reported for 1 using an EtOH solution (10 mL) of
Cu(NO3)2?3H2O (0.0242 g, 0.1 mmol) and di(2H-indazol-2-
yl)methane (L2) (0.0248 g, 0.1 mmol). Yield 88%. It is soluble
in alcohols, acetone, DMSO and DMF. Anal. calc. for
C30H26CuN10O7: C, 51.32; H, 3.73; N, 19.95. Found: C, 50.94;
H, 3.59; N, 19.51. Mp. 220 uC. IR (cm21): 3400br n(H2O), 3122w,
3013w n(C–Haromatic), 2967w n(C–Haliphatic), 1634m, 1522m
n(CLN + CLC), 1478s, 1355vs n(NO3), 1309m, 1285vs n(NO3),
1244w, 1202w, 1163m, 1140m, 1124m, 1042w, 1020w, 1008m,
989w, 916w, 848m, 824w, 808w, 759m, 745vs n(NO3), 696w,
610m. ESI MS (+, CH3CN): 559 [100] [Cu(L2)2]+, 373 [100]
[Cu(NO3)L2]+, 621 [60] [Cu(NO3)(L2)2]+. LM (CH3CN, 1 6 1023
2
(d, C2, Ph, J(13C–31P): 9.1 Hz), 131.32 (C4, Ph), 133.44 (d, C1,
Ph, 1J(13C–31P): 29.5 Hz), 134.42 (d, C3, Ph, 3J(13C–31P): 14.4
Hz), 135.67 (C3), 140.46 (C9). 31P NMR (CD3CN, 20 uC): 0.04br.
31P NMR (CD3CN, 240 uC): 0.44br. ESI MS (+, CH3CN): 587
[100] [Cu(PPh3)2]+, 573 [40] [Cu(PPh3)L1]+, 366 [10]
[Cu(PPh3)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 115 S cm2
M) = 130 S cm2 mol21
.
mol21
.
Synthesis of [Cu(O2CCF3)2(L1)] (7)
Synthesis of [Cu(L2)(Ph3P)2]NO3 (4)
Derivative 7 was prepared by following a similar procedure to
that reported for 1 using an EtOH solution (10 mL) of
Cu(O2CCF3)2 (0.0290 g, 0.1 mmol) and di(1H-indazol-1-
yl)methane (L1) (0.0248 g, 0.1 mmol). Yield 88%. It is soluble
in alcohols, acetonitrile, acetone, DMSO and DMF. Anal. calc.
for C19H12CuF6N4O4: C, 42.43; H, 2.25; N, 10.42. Found: C,
42.78; H, 2.27; N, 10.41. Mp. 225 uC. IR (cm21): 3116w, 3063w,
3016w n(C–Haromatic), 2928w, 2853w n(C–Haliphatic), 1680s br
n(CF3CO2), 1623m n(CF3CO2), 1513m n(CLN + CLC), 1467m,
1442m n(CF3CO2), 1425m, 1382w, 1363w, 1326w, 1288m,
1263m, 1185vs, 1138vs n(CF3CO2), 1057m, 1006m, 980w,
911m, 873w, 843m, 793m, 781m, 744s, 722s. ESI MS (+,
Derivative 4 was prepared by following a similar procedure to
that reported for 1 using a CH3CN solution (10 mL) of
Cu(NO3)(PPh3)2 (0.0687 g, 0.1 mmol) and an EtOH solution of
di(2H-indazol-2-yl)methane (L2) (0.0248 g, 0.1 mmol). Yield
90%. It is soluble in alcohols, chlorinated solvents, acetoni-
trile, acetone, DMSO and DMF. Anal. calc. for
C51H42CuN5O3P2: C, 68.18; H, 4.71; N, 7.80. Found: C, 67.88;
H, 4.80; N, 7.61. Mp. 173 uC. IR (cm21): 3025w n(C–Haromatic),
2978w, 2920w n(C–Haliphatic), 1631w, 1585w, 1571w, 1519w
n(CLN + CLC), 1479m, 1463m, 1433s, 1329m, 1309m, 1273m,
1183w, 1159w, 1138w, 1095s, 1070m, 1022s, 999m, 970w,
942w, 918w, 849w, 828w, 809w, 750m, 740s, 705m, 692s. 1H
NMR (CD3CN): d 6.89 (s, 2H, CH2), 7.10 (t, 2H, H6), 7.25–7.44
(m, 30H, Ph), 7.22 (t, 2H, H5), 7.62 (d, 2H, H7), 7.75 (d, 2H, H4),
8.58 (s, 2H, H9). 13C{1H}NMR (CD3CN): d 67.71 (C1), 117.81
(C4), 122.19 (C7), 122.67 (C6), 123.41 (C9), 126.72 (C8), 128.44
(C5), 129.91 (d, C2, Ph, 2J(13C–31P): 9.1 Hz), 131.25 (C4, Ph),
133.75 (d, C1, Ph, 1J(13C–31P): 27.3 Hz), 134.44 (d, C3, Ph,
3J(13C–31P): 14.4 Hz), 150.11 (C3). 31P NMR (CD3CN, 20 uC):
20.17br. 31P NMR (CD3CN, 240 uC): 20.39br. ESI MS (+,
CH3CN): 587 [100] [Cu(PPh3)2]+, 573 [60] [Cu(PPh3)L2]+, 366
[10] [Cu(PPh3)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 105 S
CH3CN):
961
[100]
559
[Cu(L1)2(CF3COO)]+,
[70]
[Cu(L1)2]+,
672
424
[90]
[20]
[Cu(O2CCF3)(L1)2]+,
[Cu(O2CCF3)(L1)]+, 352 [20] [Cu(L1)(CH3CN)]+. LM (CH3CN, 1
6 1023 M) = 26 S cm2 mol21
.
Synthesis of [Cu(O2CCF3)(L2)2](O2CCF3) (8)
Derivative 8 was prepared by following a similar procedure to
that reported for 1 using an EtOH solution (10 mL) of
Cu(O2CCF3)2 (0.0290 g, 0.1 mmol) and di(2H-indazol-2-
yl)methane (L2) (0.0248 g, 0.1 mmol). Yield 95%. It is soluble
in alcohols, acetonitrile, acetone, DMSO and DMF. Anal. calc.
for C34H24CuF6N8O4: C, 51.95.43; H, 3.08; N, 14.25. Found: C,
51.64; H, 2.65; N, 14.05. Mp. 130–131 uC. IR (cm21): 3125w,
3079w, 3028w n(C–Haromatic), 2963w, 2925w, 2849w n(C–
Haliphatic), 1667vs br n(CF3CO2), 1633s n(CF3CO2), 1522m
n(CLN + CLC), 1480m, 1425m n(CF3CO2), 1376w, 1361w,
1331w, 1308m, 1245w, 1187vs, 1163m, 1128vs n(CF3CO2),
1038m, 1007m, 990m, 961w, 916m, 844s, 795s, 758m, 742s,
725s. ESI MS (+, CH3CN): 559 [100] [Cu(L2)2]+, 672 [80]
cm2 mol21
.
Synthesis of [Cu(NO3)2(L1)] (5)
Derivative 5 was prepared by following a similar procedure to
that reported for 1 using an EtOH solution (10 mL) of
Cu(NO3)2?3H2O (0.0242 g, 0.1 mmol) and di(1H-indazol-1-
yl)methane (L1) (0.0248 g, 0.1 mmol). Yield 87%. It is soluble
in alcohols, acetonitrile, acetone, DMSO and DMF. Anal. calc.
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[Cu(O2CCF3)(L2)2]+, 425 [20] [Cu(O2CCF3)(L2)]+, 352 [20]
acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C30H24AgN9O3: C, 54.07; H, 3.63; N, 18.92. Found: C, 54.01;
[Cu(L1)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 61 S cm2 mol21
.
H, 3.77; N, 18.87. Mp. 256 uC. IR (cm21): 3110w, 3062w, 3030w
n(C–Haromatic), 2967w n(C–Haliphatic), 1771w, 1750w n(NO3),
1631m, 1517m n(CLN + CLC), 1471m, 1442w, 1431w, 1389m,
1360m, 1312s, 1298s, 1247w, 1237m, 1161s, 1145s, 1128m,
1044w, 1018w, 994w, 977m, 937w, 912m, 840m, 821m, 812m,
753m, 735vs. 1H NMR (CD3CN): d 7.02 (s, 2H, CH2), 7.12 (t, 2H,
H6), 7.29 (t, 2H, H5), 7.52 (d, 2H, H7), 7.76 (d, 2H, H4), 8.58 (s,
2H, H9). 13C{1H}NMR (CD3CN): d 68.28 (C1), 117.93 (C4), 122.14
(C7), 122.80 (C6), 123.57 (C9), 126.63 (C8), 128.66 (C5), 150.40
(C3). ESI MS (+, CH3CN): 605 [100] [Ag (L2)2]+, 398 [30]
[Ag(L2)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 116 S cm2
Synthesis of [CuCl2(L1)]2 (9)
Derivative 9 was prepared by following a similar procedure to
that reported for 1 using a MeOH solution of CuCl2 (0.0134 g,
0.1 mmol) and di(1H-indazol-1-yl)methane (L1) (0.0248 g, 0.1
mmol). Yield 85%. It is soluble in alcohols, acetonitrile,
acetone, DMSO and DMF. Anal. calc. for C30H24Cl4Cu2N8: C,
47.07; H, 3.16; N, 14.64. Found: C, 46.96; H, 3.05; N, 14.57. Mp.
148–152 uC. IR (cm21): 3105w n(C–Haromatic), 2966w n(C–
Haliphatic), 1612m, 1522w n(CLN + CLC), 1468m, 1452w,
1435m, 1352w, 1288m, 1193s, 1121w, 1004m, 938w, 905w,
837w. ESI MS (+, MeCN): 594 [100] [CuCl(L1)2]+. ESI MS (+,
CH3CN): 559 [100] [Cu(L1)2]+, 594 [80] [CuCl(L1)2]+, 352 [70]
[Cu(L1)(CH3CN)]+, 728 [40] [{CuCl(L1)}2Cl]+. LM (CH3CN, 1 6
mol21
.
Synthesis of [AgO2CCF3(L1)]2 (13)
1023 M) = 42 S cm2 mol21
.
Derivative 13 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
AgO2CCF3 (0.0221 g, 0.1 mmol) and di(1H-indazol-1-
yl)methane (L1) (0.0248 g, 0.1 mmol). Yield 71%. It is soluble
in alcohols, chlorinated solvents, acetonitrile, acetone, DMSO
and DMF. Anal. calc. for C34H24Ag2F6N8O4: C, 43.52; H, 2.58;
N, 11.94. Found: C, 43.14; H, 2.48; N, 12.18. Mp. 135–136 uC. IR
(cm21): 3068 n(C–Haromatic), 2988w, 2902w n(C–Haliphatic), 1670s
n(CF3CO2), 1652s n(CF3CO2), 1618m, 1506m n(CLN + CLC),
1463m, 1440m, 1428m, 1371m, 1315w, 1284m, 1260w, 1198s,
1168s, 1127s n(CF3CO2), 1093w, 1034w, 1005w, 946w, 904w,
863w, 833m, 796m, 768m, 746s, 720s. 1H NMR (CD3CN): d 7.00
(s, 2H, CH2), 7.20 (t, 2H, H6), 7.49 (t, 2H, H7), 7.75 (d, 2H, H5),
7.90 (d, 2H, H8), 8.07 (s, 2H, H3). 13C{1H}NMR (CD3CN): d 61.48
(C1), 110.98 (C8), 122.25 (C5), 122.65 (C6), 125.40 (C4), 128.33
(C7), 136.12 (C3), 140.46 (C9). ESI MS (+, CH3CN): 605 [100]
[Ag(L1)2]+, 396 [80] [Ag(L1)(CH3CN)]+, 189 [60] [Ag (CH3CN)2]+.
Synthesis of [CuCl2(L1)(DMF)] (10)
Derivative 10 was prepared by following a similar procedure to
that reported for 9 using a DMF solution of CuCl2 (0.0134 g,
0.1 mmol) and di(1H-indazol-1-yl)methane (L1) (0.0248 g, 0.1
mmol). Yield 77%. It is soluble in alcohols, acetonitrile,
acetone, DMSO and DMF. Anal. cal. for C18H19Cl2CuN5O: C,
47.43; H, 4.20; N, 15.36. Found: C, 47.19; H, 4.14; N, 15.09. Mp.
190–192 uC. IR (cm21): 3122w n(C–Haromatic), 3000w, 2998 n(C–
Haliphatic), 1680 n(CLODMF), 1641m, 1533m n(CLN + CLC),
1529m, 1489w, 1434w, 1382w, 1295m, 1244s, 1115w, 1034m,
913w, 844m, 747s, 736s. ESI MS (+, CH3CN): 594 [80]
[CuCl(L1)2]+, 728 [20] [{CuCl(L1)}2Cl]+, 559 [10] [Cu(L1)2]+, 352
[10] [Cu(L1)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 46 mS cm21
.
Synthesis of [Ag(L1)2]NO3 (11)
Di(1H-indazol-1-yl)methane (L1) (0.0248 g, 0.1 mmol) was
added to an acetonitrile solution (10 mL) of AgNO3 (0.0170 g,
0.1 mmol). The colorless solution was stirred overnight at
room temperature. By slow evaporation of the solvent, a
colorless microcrystalline powder was afforded, which was
filtered off, dried to constant weight and shown to be
derivative 11. Yield 96%. It is soluble in alcohols, acetonitrile,
acetone, DMSO and DMF. Anal. calc. for C30H24AgN9O3: C,
54.07; H, 3.63; N, 18.92. Found: C, 54.19; H, 3.59; N, 18.82. Mp.
155 uC. IR (cm21): 3109w, 3067w n(C–Haromatic), 2968w, 2925w,
2854w n(C–Haliphatic),1744w n(NO3), 1618m, 1505m n(CLN +
CLC), 1466w, 1432w, 1344s, 1314s, 1282s, 1265s, 1216w,
1194w, 1168m, 1129w, 1114w, 1035w, 1007w, 950m, 907m,
LM (CH3CN, 1 6 1023 M) = 204 S cm2 mol21
.
Synthesis of [AgO2CCF3(L2)]2 (14)
Derivative 14 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
AgO2CCF3 (0.0221 g, 0.1 mmol) and di(2H-indazol-2-
yl)methane (L2) (0.0248 g, 0.1 mmol). Yield 94%. It is soluble
in acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C34H24Ag2F6N8O4: C, 43.52; H, 2.58; N, 11.94. Found: C, 43.18;
H, 2.20; N, 11.39. Mp. 102–103 uC. IR (cm21): 3122w, 3109w,
3074w, 3027w n(C–Haromatic), 2945w, 2913w, 2835w n(C–
Haliphatic), 1653vs n(CF3CO2), 1634s n(CF3CO2), 1520m n(CLN
+ CLC), 1474m, 1421m, 1378m, 1364m, 1314m, 1302w, 1243w,
1199vs, 1186vs, 1158m, 1129s n(CF3CO2), 1027m, 999w, 984w,
913m, 834s, 807m, 793m, 755s, 739vs, 721vs. 1H NMR
(CD3CN): d 7.10 (s, 2H, CH2), 7.13 (t, 2H, H6), 7.30 (t, 2H,
H5), 7.52 (d, 2H, H7), 7.76 (d, 2H, H4), 8.67 (s, 2H, H9).
13C{1H}NMR (CD3CN): d 67.96 (C1), 117.72 (C4), 122.24 (C7),
122.67 (C6), 123.80 (C9), 127.36 (C8), 129.18 (C5), 150.42 (C3).
ESI MS (+, CH3CN): 603 [70] [Ag(L2)2]+, 396 [60]
[Ag(L2)(CH3CN)]+, 189 [100] [Ag(CH3CN)2]+. LM (CH3CN, 1 6
1
870w, 844m, 813w, 768w, 741m. H NMR (CD3CN): d 7.00 (s,
2H, CH2), 7.14 (t, 2H, H6), 7.29 (t, 2H, H7), 7.56 (d, 2H, H9),
7.79 (d, 2H, H5), 8.28 (s, 2H, H3). 13C{1H}NMR (CD3CN): d 61.48
(C1), 110.97 (C8), 122.26 (C5), 122.66 (C6), 125.42 (C4), 128.35
(C7), 136.13 (C3), 140.43 (C9). ESI MS (+, CH3CN): 603 [50] [Ag
(L1)2]+, 148 [100] [Ag(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 169
S cm2 mol21
.
Synthesis of [AgNO3(L2)2] (12)
1023 M) = 176 S cm2 mol21
.
Derivative 12 was prepared by following the same procedure
described for 11 using an acetonitrile solution (10 mL) of
AgNO3 (0.0170 g, 0.1 mmol) and di(2H-indazol-2-yl)methane
(L2) (0.0248 g, 0.1 mmol). Yield 93%. It is soluble in alcohols,
Synthesis of [Ag(L1)2]CH3SO3 (15)
Derivative 15 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
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AgCH3SO3 (0.0203 g, 0.1 mmol) and di(1H-indazol-1-
yl)methane (L1) (0.0248 g, 0.1 mmol). Yield 72%. It is soluble
in alcohol, chlorinated solvents, acetonitrile and DMSO. Anal.
calc. for C31H27AgN8O3S: C, 53.23; H, 3.89; N, 16.02; S, 4.58.
Found: C, 53.18; H, 3.86; N, 15.76; S, 4.73. Mp. 100–101 uC. IR
(cm21): 3102w, 3065w, 3031w n(C–Haromatic), 2991w, 2971w,
2945w n(C–Haliphatic), 1618m, 1505m n(CLN + CLC), 1466m,
1448w, 1432w, 1395w, 1381m, 1364m, 1286s, 1265m, 1199s,
1184s, 1167s br n(SO3), 1128w, 1113w, 1094w, 1037s n(CH3SO3),
1006m, 949m, 907m, 871w, 833m, 766s, 742vs. 1H NMR
(CD3CN): d 2.49 (s, 3H, CH3) 6.97 (s, 2H, CH2), 7.20 (t, 2H, H6),
7.49 (t, 2H, H7), 7.74 (d, 2H, H5), 7.90 (d, 2H, H8), 8.06 (s, 2H,
H3). 13C{1H}NMR (CD3CN): d 39.77 (CH3), 61.57 (C1), 111.01
(C8), 122.20 (C5), 122.58 (C6), 125.45 (C4), 128.22 (C7), 135.94
(C3), 140.47 (C9). ESI MS (+, CH3CN): 603 [100] [Ag(L1)2]+, 396
[30] [Ag(L1)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 167 S cm2
[90] [Ag(CH3CN)2]+. LM (CH3CN, 1 6 1023 M) = 154 S cm2
mol21
.
Synthesis of [AgCF3SO3(L2)] (18)
Derivative 18 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
AgCF3SO3 (0.0257 g, 0.1 mmol) and di(2H-indazol-2-
yl)methane (L2) (0.0248 g, 0.1 mmol). Yield 75%. It is soluble
in alcohols, acetonitrile, acetone, DMSO and DMF. Anal. calc.
for C16H12AgF3N4O3S: C, 38.04; H, 2.39; N, 11.09, S, 6.35.
Found: C, 38.37; H, 2.21; N, 10.94, S, 6.14. Mp. 166–168 uC. IR
(cm21): 3116w, 3084w n(C–Haromatic), 2988w, 2901w n(C–
Haliphatic), 1632m, 1556w, 1521m n(CLN + CLC), 1468m,
1446w, 1432w, 1418w, 1395w, 1379w, 1360m, 1340w, 1297m,
1253s n(CF3SO3), 1240s n(CF3SO3), 1224s n(CF3SO3), 1191m,
1163s n(CF3SO3), 1142s n(CF3SO3), 1130m, 1022s, 1011s, 946w,
913m, 843m, 817m, 7573, 735s. 1H NMR (CD3CN): d 7.08 (s,
2H, CH2), 7.13 (t, 2H, H6), 7.29 (t, 2H, H5), 7.45 (d, 2H, H7),
7.78 (d, 2H, H4), 8.65 (s, 2H, H9). 13C{1H}NMR (CD3CN): d 67.97
(C1), 117.51 (C4), 122.32 (C7), 122.67 (C6), 123.94 (C9), 127.60
(C8), 129.45 (C5), 150.44 (C3). ESI MS (+, CH3CN): 603 [100]
[Ag(L2)2]+, 398 [80] [Ag(L2)(CH3CN)]+. LM (CH3CN, 1 6 1023 M)
mol21
.
Synthesis of [AgCH3SO3(L2)] (16)
Derivative 16 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
AgCH3SO3 (0.0203 g, 0.1 mmol) and di(2H-indazol-2-
yl)methane (L2) (0.0248 g, 0.1 mmol). Yield 75%. It is soluble
in alcohols, acetonitrile, DMSO and DMF. Anal. calc. for
C16H15AgN4O3S: C, 42.59; H, 3.35; N, 12.42; S, 7.11. Found: C,
42.25; H, 3.23; N, 12.18, S, 7.01. Mp. 104 uC. IR (cm21): 3096w,
3051w, 3032w n(C–Haromatic), 2930w n(C–Haliphatic), 1631m,
1553w, 1520m n(CLN + CLC), 1477w, 1469m, 1445w, 1431w,
1418w, 1395w, 1377w, 1357m, 1340w, 1326w, 1298m, 1239w,
1184s n(CH3SO3), 1155vs n(CH3SO3), 1144s, 1130s, 1034s
n(CH3SO3), 1015s n(CH3SO3), 984w, 938w, 912m, 842m,
822m, 766m, 758s, 735vs. 1H NMR (CD3CN): d 2.51 (s, 3H,
CH3), 7.12 (s, 2H, CH2), 7.15 (t, 2H, H6), 7.37 (t, 2H, H5), 7.58
(d, 2H, H7), 7.78 (d, 2H, H4), 8.77 (s, 2H, H9). 13C{1H}NMR
(CD3CN): d 39.81 (CH3), d 67.75 (C1), 117.55 (C4), 122.35 (C7),
122.59 (C6), 123.82 (C9), 127.78 (C8), 129.39 (C5), 150.35 (C3).
ESI MS (+, CH3CN): 189 [100] [Ag(CH3CN)2]+, 603 [90]
[Ag(L2)2]+, 398 [80] [Ag(L2)(CH3CN)]+. LM (CH3CN, 1 6 1023
= 109 S cm2 mol21
.
Synthesis of [Ag(L1)2]ClO4 (19)
Derivative 19 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of AgClO4
(0.0207 g, 0.1 mmol) and di(1H-indazol-1-yl)methane (L1)
(0.0248 g, 0.1 mmol). Yield 82%. It is soluble in alcohols,
acetone, acetonitrile, DMSO and DMF. Anal. calc. for
C30H24AgClN8O4: C, 51.19; H, 3.44; N, 15.92. Found: C, 50.88;
H, 3.34; N, 15.66. Mp. 251–253 uC. IR (cm21): 3117w, 3069w
n(C–Haromatic), 2978w, 2938w n(C–Haliphatic), 1618m, 1505w
n(CLN + CLC), 1466m, 1445w, 1431m, 1380w, 1362w, 1319w,
1283m, 1264m, 1218w, 1195w, 1169w, 1074br n(ClO4), 1035w,
975w, 947m, 906m, 864w, 841w, 768m, 744s. 1H NMR
(CD3CN): d 6.96 (s, 2H, CH2), 7.20 (t, 2H, H6), 7.47 (t, 2H,
H7), 7.74 (d, 2H, H5), 7.88 (d, 2H, H8), 8.04 (s, 2H, H3).
13C{1H}NMR (CD3CN): d 61.06 (C1), 110.78 (C8), 122.44 (C5),
122.90 (C6), 125.12 (C4), 128.84 (C7), 136.75 (C3), 140.40 (C9).
ESI MS(+, CH3CN): 605 [100] [Ag(L1)2]+. LM (CH3CN, 1 6 1023
M) = 126 S cm2 mol21
.
Synthesis of [AgCF3SO3(L1)2] (17)
M) = 212 S cm2 mol21
.
Derivative 17 was prepared by following the same procedure
described for 11 using a methanol solution (10 mL) of
AgCF3SO3 (0.0257 g, 0.1 mmol) and di(1H-indazol-1-
yl)methane (L1) (0.0248 g, 0.1 mmol). Yield 80%. It is soluble
in alcohols, chlorinated solvents, acetonitrile, acetone, DMSO
and DMF. Anal. calc. for C31H24AgF3N8O3S: C, 49.41; H, 3.21;
N, 14.87; S, 4.26. Found: C, 49.65; H, 3.06; N, 14.67; S, 4.35.
Mp. 212–213 uC. IR (cm21): 3149w, 3109w, 3079w n(C–
Haromatic), 2999w n(C–Haliphatic), 1622m, 1511m n(CLN + CLC),
1467m, 1431m, 1418w, 1386m, 1372m, 1327m, 1274s
n(CF3SO3), 1234s n(CF3SO3), 1220s n(SO3), 1198s, 1167s
n(CF3SO3), 1154vs n(CF3SO3), 1095m, 1053m, 1021s, 986m,
Synthesis of [Ag(L2)]ClO4 (20)
Derivative 20 was prepared by following the same procedure
described for 11 using an acetonitrile solution (10 mL) of
AgClO4 (0.0207 g, 0.1 mmol) and di(2H-indazol-2-yl)methane
(L2) (0.0248 g, 0.1 mmol). Yield 78%. It is soluble in alcohols,
acetone, acetonitrile, DMSO and DMF. Anal. calc. for
C15H12AgClN4O4: C, 39.54; H, 2.65; N, 12.30. Found: C, 39.41;
H, 2.70; N, 12.06. Mp. 253–255 uC. IR (cm21): 3117w, 3079w,
3028w n(C–Haromatic), 2986w, 2922w n(C–Haliphatic), 1631m,
1553w, 1520m n(CLN + CLC), 1470m, 1446w, 1434w, 1419w,
1378m, 1362m, 1334w, 1296m, 1241w, 1163m, 1072s br
n(ClO4), 994m, 980m, 912m, 842m, 807m, 794m, 756s, 740s.
1H NMR (CD3CN): d 7.05 (s, 2H, CH2), 7.12 (t, 2H, H6), 7.28 (t,
2H, H5), 7.46 (d, 2H, H7), 7.78 (d, 2H, H4), 8.62 (s, 2H, H9).
13C{1H}NMR (CD3CN): d 68.05 (C1), 117.68 (C4), 122.26 (C7),
122.70 (C6), 123.83 (C9), 127.23 (C8), 129.22 (C5), 150.43 (C3).
1
959m, 911w, 904w, 858m, 850m, 837m, 775m, 744vs. H NMR
(CD3CN): d 7.00 (s, 2H, CH2), 7.22 (t, 2H, H6), 7.52 (t, 2H, H7),
7.76 (d, 2H, H5), 7.93 (d, 2H, H8), 8.13 (s, 2H, H3). 13C{1H}NMR
(CD3CN): d 61.40 (C1), 110.92 (C8), 122.29 (C5), 122.71 (C6),
125.36 (C4), 128.44 (C7), 136.23 (C3), 140.44 (C9). ESI MS (+,
CH3CN): 603 [100] [Ag(L1)2]+, 396 [80] [Ag(L1)(CH3CN)]+, 189
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ESI MS (+, CH3CN): 605 [100] [Ag(L2)2]+, 396 [90]
133.80 (C7), 138.96 (C3), 140.49 (C9). ESI MS (+, MeCN): 515 [60]
[Ag(L2)CH3CN]+. LM (CH3CN, 1 6 1023 M) = 174 S cm2 mol21
.
[AuCl2(L1)]+. LM (CH3CN, 1 6 1023 M) = 100 S cm2 mol21
.
Synthesis of [Ag(L1)2]BF4 (21)
Synthesis of [AuCl2(L2)][AuCl4] (24)
Derivative 21 was prepared by following the same procedure
described for 11 using an acetonitrile solution (10 mL) of
AgBF4 (0.0195 g, 0.1 mmol) and di(1H-indazol-1-yl)methane
(L1) (0.0248 g, 0.1 mmol). Yield 75%. It is soluble in alcohols,
acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C30H24AgBF4N8: C, 52.13; H, 3.50; N, 16.21. Found: C, 51.95;
H, 3.24; N, 15.89. Mp. 296–298 uC. IR (cm21): 3129w, 3111w,
3063w, 3028w n(C–Haromatic), 2951w, 2935w n(C–Haliphatic),
1618m, 1506m n(CLN + CLC), 1466m, 1447m, 1431m, 1382w,
1362m, 1320w, 1281m, 1264m, 1218w, 1169m, 1155w, 1096m,
1051s n(BF4), 1035s n(BF4), 1010m, 976w, 947m, 906m, 865m,
842m, 769m, 743s, 734s. 1H NMR (CD3CN): d 6.96 (s, 2H, CH2),
7.20 (t, 2H, H6), 7.48 (t, 2H, H7), 7.74 (d, 2H, H5), 7.88 (d, 2H,
H8), 8.04 (s, 2H, H3). 13C{1H}NMR (CD3CN): d 61.63 (C1),
111.02 (C8), 122.17 (C5), 122.55 (C6), 125.50 (C4), 128.15 (C7),
135.82 (C3), 140.47 (C9). ESI MS (+, CH3CN): 603 [100]
A solution of anhydrous AuCl3 (0.080 g, 0.26 mmol) in
acetonitrile (2 mL) was added to a solution of di(2H-indazol-
2-yl)methane (L2) (0.05 g, 0.2 mmol) in the same solvent (3
mL). The resulting suspension was stirred for 48 h. The orange
precipitate formed was filtered and washed with MeCN (6 mL).
Re-crystallisation from MeCN gave red crystals. Yield 67%. It is
soluble in acetonitrile, DMSO and DMF. Anal. calc. for
C15H12Au2Cl6N4: C, 21.08; H, 1.41; N, 6.55. Found: C, 21.07;
H, 1.45; N, 6.88. Mp. 198 uC. IR (cm21): 3104w n(C–Haromatic),
2998w, 2946w n(C–Haliphatic), 1626m, 1524m n(CLN + CLC),
1486m, 1460m, 1431m, 1373m, 1351w, 1313m, 1288w, 1239m,
1163m, 1143w, 1127m, 1012m, 921m, 750w, 372s, 319s. 1H
NMR (CD3CN-d6): d 7.31 (s, 2H, CH2), 7.57 (t, 2H, H6), 7.77 (t,
2H, H5), 7.91 (d, 2H, H7), 8.15 (d, 2H, H4), 9.17 (s, 2H, H9).
13C{1H}NMR (CD3CN): 65.21 (C1), 113.08 (C4), 121.40 (C7),
124.25 (C6), 127.50 (C9), 136.40 (C8), 136.85 (C5), 143.22 (C3).
ESI MS (+, MeCN): 515 [40] [AuCl2(L2)]+. LM (CH3CN, 1 6 1023
[Ag(L1)2]+. LM (CH3CN, 1 6 1023 M) = 179 S cm2 mol21
.
M) = 132 S cm2 mol21
.
Synthesis of [Ag(L2)2]BF4 (22)
Experimental X-ray structural analysis
Derivative 22 was prepared by following the same procedure
described for 11 using an acetonitrile solution (10 mL) of
AgBF4 (0.0195 g, 0.1 mmol) and di(2H-indazol-2-yl)methane
(L2) (0.0248 g, 0.1 mmol). Yield 77%. It is soluble in alcohols,
acetonitrile, acetone, DMSO and DMF. Anal. calc. for
C30H24AgBF4N8: C, 52.13; H, 3.50; N, 16.21. Found: C, 51.84;
H, 3.18; N, 15.75. Mp. 259–261 uC. IR (cm21): 3128w, 3048w
n(C–Haromatic), 2931w, 2925w n(C–Haliphatic), 1631m, 1519m
n(CLN + CLC), 1473m, 1436w, 1420w, 1393w, 1361w, 1331w,
1304m, 1241w, 1159m, 1134m, 1052s n(BF4), 1037s n(BF4),
993m, 979m, 912m, 840m, 804m, 758s, 730s. 1H NMR
(CD3CN): d 6.99 (s, 2H, CH2), 7.12 (t, 2H, H6), 7.30 (t, 2H,
H5), 7.53 (d, 2H, H7), 7.76 (d, 2H, H4), 8.56 (s, 2H, H9).
13C{1H}NMR (CD3CN): d 67.83 (C1), 117.40 (C4), 122.38 (C7),
122.60 (C6), 123.98 (C9), 127.90 (C8), 129.65 (C5), 150.42 (C3).
ESI MS (+, CH3CN): 603 [100] [Ag(L2)2]+, 369 [90]
[Ag(L2)(CH3CN)]+. LM (CH3CN, 1 6 1023 M) = 194 S cm2
Crystals of a suitable size for X-ray diffraction analysis were
coated with dry perfluoropolyether, mounted onto glass fibers
and fixed in a cold nitrogen stream (T = 100 K) to the
goniometer head. Data collections were performed on a
Bruker-Nonius X8Apex-II CCD diffractometer using monochro-
matic radiation l(Mo–Ka) = 0.71073 Å by means of v and Q
scans with a width of 0.50u. The data were reduced (SAINT)13
and corrected for absorption effects by the multi-scan method
(SADABS).14 The structures were solved by direct methods (SIR-
2002)15 and refined against all F2 data by full-matrix least-
squares techniques (SHELXTL-6.12),16 minimizing w[Fo
2
2
2 2
Fc ] . All the non-hydrogen atoms were refined with aniso-
tropic displacement parameters. Hydrogen atoms were
included in calculated positions and allowed to ride on the
attached atoms with the isotropic temperature factors (Uiso
values) fixed at 1.2 times (1.5 times for methyl groups) the Ueq
values of the corresponding attached atoms.
mol21
.
Synthesis of [AuCl2(L1)][AuCl4] (23)
A solution of anhydrous AuCl3 (0.080 g, 0.26 mmol) in
acetonitrile (2 mL) was added to a solution of di(1H-indazol-
1-yl)methane (L1) (0.05 g, 0.2 mmol) in the same solvent (3
mL). The resulting suspension was stirred for 48 h. The red
precipitate formed was filtered and washed with MeCN (6 mL).
Re-crystallisation from MeCN gave red crystals. Yield 69%. It is
soluble in acetonitrile, DMSO and DMF. Anal. calc. for
C15H12Au2Cl6N4: C, 21.08; H, 1.41; N, 6.55. Found: C, 21.19;
H, 1.23; N, 6.55. Mp. 205 uC. IR (cm21): 3591w, 3125w, 3008w
n(C–Haromatic), 2966w, 2936w n(C–Haliphatic), 1622m, 1514m
n(CLN + CLC), 1463m, 1380m, 1366m, 1286w, 1254m, 1232w,
1189m, 1179m, 1122w, 1067m, 989m, 911vs, 866w, 846m,
792m, 751s, 590s, 498s, 429s, 382s, 361s. 1H NMR (CD3CN):
7.25 (s, 2H, CH2), 7.55 (t, 2H, H6), 7.95 (t, 2H, H7), 8.09 (d, 2H,
H9), 8.12 (d, 2H, H5), 9.10 (s, 2H, H3). 13C{1H}NMR (CD3CN):
58.47 (C1), 110.41 (C8), 121.59 (C5), 123.46 (C6), 125.24 (C4),
Results and discussion
Syntheses and characterization of the di(indazolyl)methane
complexes
Derivatives 1–24 (Charts 2–4) were obtained by a general
procedure in which the metal acceptor, [MXm(PR3)n] (for 1–4:
M = Cu(I), Xm = ClO4 or NO3, R = Cy or Ph, n = 2; 5–10: M =
Cu(II), X = NO3, CF3COO, Cl, m = 2, n = 0; 11–22: M = Ag, X =
ClO4, CF3COO, CF3SO3, CH3SO3, NO3, or BF4, m = 1, n = 0; 23–
24: M = Au(III), X = Cl, m = 3, n = 0) and the nitrogen donor L (L
in general, in detail L1 = di(1H-indazol-1-yl)methane, L2
=
di(2H-indazol-2-yl)methane) were mixed in acetonitrile (1–4,
11–12 and 20–24), ethanol (5–8) methanol (9 and 13–19) or
DMF (10) in a 1 : 1 molar ratio and the resulting solutions
stirred at room temperature for 24 h (apart for Au(III)
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Chart 2
derivatives 23–24, where the resulting suspensions were stirred
for 48 h) after which, crystalline deposits slowly formed by
solvent evaporation. Despite the variation in the ligand : metal
ratio of the reactants from 1 : 1 to 2 : 1, the same results were
always obtained.
The copper and silver derivatives 1–22 (Charts 2 and 3,
respectively) are soluble in alcohols, acetonitrile, acetone,
DMSO and DMF, whereas the Au(III) complexes 23 and 24
(Chart 4) are soluble in acetonitrile, DMSO and DMF.
Conductivity measurements of acetonitrile solutions of 1–4,
6 and 11–24 gave values in the range of 100–212 S cm2 mol21
,
typical of 1 : 1 electrolytes.17 These results appear to contrast
with those obtained from the solid state IR spectra of
derivatives 12–14 and 16–18, where there is clear evidence of
counter-ions interacting with silver (further confirmed by the
X-ray structural analyses, see below). However, they suggest
complete ionic dissociation of these species in solution.
In fact, in the IR spectrum of 12, two weak n1 + n4
combination bands in the overtone region of 1700–1800
cm21 have been detected, in accordance with the occurrence
of a coordinated nitrate group.18 In the IR spectra of 13 and 14,
the difference between the asymmetric and symmetric
n(CF3CO2) of ca. 20 cm21 is in accordance with bidentate
carboxylates,19 and finally in the IR spectra of 16–18, a fine
splitting of the strong bands due to the stretching modes of
SO3 in the range of 1274–1015 cm21 has been observed, which
Chart 3
is typical of coordinated RSO3 counter-ions.20 In contrast, the
IR data of 1–4, 6, 11, 15 and 19–22 are in good agreement with
the solution conductivity data, the IR spectra always showing
typical absorption bands due to ionic perchlorate in 1, 2, 19
and 20, ionic BF4 in 21 and 22 21 and ionic nitrate in 3, 4, and
11.22 Derivative 20 deserves to be discussed in more detail: on
the basis of the spectral and conductivity data and in the
absence of X-ray data, we have hypothesized, at least in the
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derivatives.10 The observed downfield shift is additional
evidence in favor of the existence, at least partially, of the
complexes in that solvent. Additionally, in the 1H NMR spectra
of derivatives 1–4, proton resonances due to PR3 have also
been observed with the correct 2 : 1 integration ratio with
respect to those of the N-donor ligands. Moreover, 31P NMR
spectra at 20 uC and at 240 uC have also been carried out for 1–
4.
Chart 4
Those complexes containing PPh3 do not show any
detectable change, only a broad resonance which is always
observed at 20.4 ppm at all temperatures, whereas those
compounds with the more hindered PCy3 display two broad
resonances at room temperature and some additional splitting
on cooling and three sharp resonances observed at 240 uC. As
the peak at ca. 10 ppm corresponds to free PCy3, the other two
resonances are assigned to species containing one and two
phosphines, in accordance with partial dissociation in
acetonitrile, as also confirmed by ESI MS spectroscopy.23
solid state, a polynuclear structure with cationic chains and
ionic perchlorate ions dispersed within them (Chart 3). Our
hypothesis originates from the evidence that L2 seems suitable
to bridge two Ag centres, as found in the X-ray structure of 16
(see the X-ray discussion below), and because a mononuclear
Ag derivative with only an L2 chelating ligand and an ionic
perchlorate seems unlikely. The conductance values for the
Cu(II) derivatives 5 and 7–10 fall instead between 26–61 S cm2
mol21, well below the range typical for 1 : 1 electrolytes. This
is also in accordance with the IR data, which indicate the
presence of coordinated counter-ions in the solid structure
(the X-ray data also converge with this conclusion, see below)
which, however, partially dissociate in acetonitrile. Only in the
case of derivative 8 does a conductance value of 61 S cm2
mol21 not seem consistent with the X-ray crystal structure (see
below) and with its IR spectrum, where one trifluoroacetate is
clearly anionic in the solid state and partial re-association of
the counter-ion likely operating in acetonitrile.
Crystal structure of 3
Colourless crystals of
3 suitable for single-crystal X-ray
diffraction analysis were obtained by slow evaporation of the
solvents in the reaction mixture (ethanol–acetonitrile, 1 : 1) at
room temperature. Compound 3 crystallizes in the monoclinic
space group P21/n (Table 1). The asymmetric unit contains one
cationic [Cu(PPh3)2(L1)]+ molecule, one free nitrate anion
(Fig. 1a), one acetonitrile molecule of crystallization and one
disordered ethanol molecule of crystallization. In 3, the angles
around the central copper(I) ion indicate that it is in a
distorted tetrahedral coordination. The coordination sphere of
copper is formed by two N atoms of one L1 ligand and by two P
atoms of two triphenylphosphine ligands. The Cu–N bond
lengths and the Cu–P bond lengths, shown in Table 3, are
In the 1H and 13C NMR spectra, recorded for the
diamagnetic derivatives 1–4 and 11–24 in CD3CN, most of
the protonic resonances due to the L ligands are slightly
displaced towards the lower field upon coordination, as
already seen in the analogous zinc, cadmium and mercury
Table 1 Summary of the crystallographic data and structure refinement results for 3, 8, 9, 10, 11, 12 and 13(a and b)
3
8
9
10
11
12
13(a and b)
Formula
C
51H42CuN4P2?NO3?
C
32H24CuF3N8O2?
C
30H24Cl4Cu2N8 C18H19Cl2CuN5O C30H24AgN8? C30H24AgN9O3 C34H24Ag2F6N8O4
C2H6O?C2H3N
985.50
Monoclinic
P21/n
14.9116(6)
21.1567(9)
16.8197(6)
90.00
110.7150(10)
90.00
4963.2(3)
4, 2056
1.319
0.557
25.2
C2F3O2?C2H6O
832.22
NO3
666.45
Monoclinic Monoclinic
P21/c
Fw
765.45
Monoclinic
C2/c
18.3110(7)
15.5229(6)
13.5546(9)
90.00
128.0440(10)
90.00
3034.2(3)
4, 1544
1.676
1.791
25.2
22 059
2756
199
455.82
Orthorhombic
Pbca
666.45
938.35
Triclinic
¯
P1
Crystal system
Space group
a, Å
b, Å
c, Å
Triclinic
¯
P1
P21/c
11.7362(2)
12.7941(3)
13.0346(3)
79.9940(10)
85.8750(10)
74.6510(9)
1857.99(8)
2, 850
1.488
0.672
25.2
45 021
9.4972(4)
18.6410(7)
21.2437(7)
90.00
90.00
90.00
3760.9(2)
8, 1864
1.610
1.465
25.2
11.1130(3)
12.0540(3)
20.2158(5)
90.00
95.6670(10) 106.056(2)
90.00 90.00
2694.79(12) 2783.8(3)
4, 1352
1.643
0.801
25.2
13.0088(7)
15.4845(8)
14.3809(8)
90.00
8.3882(15)
14.560(3)
15.502(3)
71.291(4)
89.483(5)
80.025(4)
1763.9(5)
2, 928
a, u
b, u
c, u
V, Å3
Z, F(000)
Dcalc, Mg m23
m, mm21
hmax, u
4, 1352
1.590
0.775
30.6
1.767
1.193
25.2
No. reflns collected 43 638
27 232
3397
246
23 453
4695
388
34 239
8364
388
27 870
6395
388
No. reflns used
No. of param.
8913
643
6528
507
0.0575
0.1762
R1(F) [F2 . 2s(F2)]a 0.0662
wR2(F2)b (all data) 0.2219
0.0407
0.1117
1.052
0.0266
0.0710
1.063
0.0273
0.0663
1.040
0.0377
0.1016
1.049
0.0504
0.1964
1.037
Sc (all data)
1.074
1.066
a
b
2
c
2
R1(F) = g(|Fo| 2 |Fc|)/g|Fo| for the observed reflections [F2 . 2s(F2)]. wR2(F2) = {g[w(Fo 2 Fc2)2]/gw(Fo2)2}1/2
p)}1/2 (n = number of reflections, p = number of parameters).
.
S = {g[w(Fo 2 Fc2)2]/(n 2
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The adjacent cationic [Cu(PPh3)2(L1)]+ molecules are stacked
mainly in an edge-to-face fashion, with the shortest contacts
widespread between 2.949 Å and 2.696 Å from the phenyl–
pyrazolyl rings and the hydrogen atoms of the neighbouring
phenyl ring of triphenylphosphine, so showing the existence of
significant intermolecular aromatic interactions that arrange
the copper complex 3 into a three-dimensional array.
Crystal structure of 8
Good colourless single crystals of 8 were grown from an
aqueous ethanol solution by slow solvent evaporation at room
temperature. This compound crystallizes in the triclinic space
¯
group P1 (Table 1). The asymmetric unit contains one cationic
[Cu(TFA)(L2)]+ moiety (Fig. 1b), one free trifluoroacetate anion
(TFA = [CF3CO2]2) and an ethanol crystallization molecule.
The copper(II) ion lies in a slightly distorted square pyramidal
geometry (t = 0.03, the structure index is defined as t = (b 2 a)/
60, where a and b are the bond angles involving the trans
donor atoms in the basal plane, t = 0 for square pyramidal (SP)
and t = 1 for trigonal pyramidal (TBP) geometry).25 The
equatorial plane is completed by two N atoms of one L2 ligand,
one O from a TFA ligand and one N atom from another L2
ligand, which provides the other N atom to an apical site,
completing the coordination sphere. The average Cu–X (X = N
or O) equatorial bond length is 2.002(3) Å (Table 3). The apical
Cu–N [2.212(3) Å] distance is longer than the normal Cu–N
bond length but shorter than the sum of the van der Waals
radii of the copper and nitrogen atoms, which indicates a weak
interaction between them.26 The copper atom deviates from
the equatorial plane of 0.184 Å. One O atom from the
carboxylic group of the free trifluoroacetate anion forms a
strong hydrogen bond with the hydroxyl group from the
ethanol crystallization molecule. The adjacent cationic mole-
Fig. 1 Molecular views of copper compounds 3 (a), 8 (b) (for clarity only the
cations are displayed), 9 (c) and 10 (d). The displacement ellipsoids are drawn at
the 30% probability level. All H atoms are omitted for clarity.
comparable to those reported for other [Cu(PAr3)2(azol)]
complexes.24 The P(1)–Cu(1)–P(2) angle = 124.07(5)u and shows
the largest deviation from an idealized tetrahedral angle,
whereas the smallest deviation is shown by N(2)–Cu(1)–N(4) =
94.31(14)u. The disordered ethanol crystallization molecule
was modelled over two positions in fixed 50 : 50 occupancies,
both in suitable positions to form hydrogen bonds, and in
such a way that one part forms one hydrogen bond with the
nitrate anion and the other part with the acetonitrile molecule.
Table 2 Summary of the crystallographic data and structure refinement results for 14, 15, 16, 17(a and b), 19, 21, 23 and 24
14 15 16 17(a and b) 19 21 23
C34H24Ag2 C30H24AgN8?
24
Formula
C16H15Ag
C31H24AgF3N8O3S?
C
30H24AgN8? C30H24AgN8? C15H12AuCl2N4? C15H12AuCl2N4?
F6N8O4
938.35
CH3O3S
699.54
N4O3S
451.25
C30H24AgN8?CF3O3S ClO4
BF4
691.25
AuCl4
854.92
AuCl4?2(C2H3N)
937.03
Orthorhombic
P212121
7.9242(7)
15.9274(12)
20.1872(16)
90.00
90.00
90.00
2547.9(4)
4, 1736
2.443
Fw
1507.02
Triclinic
P1
703.89
Crystal system
Space group
a, Å
b, Å
c, Å
Tetragonal Monoclinic Triclinic
P41212
Monoclinic Monoclinic Triclinic
P21/c
¯
¯
¯
C2/c
P1
P21/c
11.3230(7)
12.1730(8)
20.4002(13) 10.6524(6)
90.00 67.967(1)
P1
12.1082(3) 43.4103(9)
12.1082(3) 12.3013(3)
24.2726(7) 19.7415(4)
90.00
90.00
90.00
6.8541(4)
10.2636(6)
12.8115(7)
90.296(2)
12.0012(8)
12.6108(8)
21.0839(14)
81.438(2)
11.3429(3)
12.3026(4)
20.4226(6)
90.00
10.5418(6)
10.6453(7)
a, u
90.00
b, u
112.0110(10) 100.4080(10) 85.256(2)
90.00 95.7830(10) 74.156(1)
95.3780(10) 95.9300(10) 71.490(2)
c, u
90.00
90.00
78.281(2)
1045.98(11)
2, 780
2.714
14.785
30.6
V, Å3
3558.57(16) 9773.6(4)
881.67(9)
1.700
1.676
1.284
30.5
3032.5(3)
2, 1520
1.650
0.801
25.2
2837.37(15) 2796.8(3)
Z, F(000)
Dcalc, Mg m23
m, mm21
hmax, u
No. reflns
collected
No. reflns used
No. of param.
8, 1856
1.751
1.183
30.5
12, 4272
1.426
0.727
25.2
46 746
4, 1424
1.648
0.858
30.5
4, 1392
1.642
0.785
25.2
12.154
25.2
39 194
43 786
20 960
58 204
37 798
40 511
23 614
5443
282
8815
619
0.0643
0.2100
1.106
3145
227
0.0265
0.0765
1.069
18 544
847
0.0634
0.1759
1.018
8441
397
0.0413
0.1177
1.041
5068
425
0.0324
0.0874
1.057
6273
244
0.0221
0.0447
1.000
4556
301
0.0239
0.0577
1.045
R1(F) [F2 . 2s(F2)]a 0.03494
wR2(F2)b (all data) 0.0960
Sc (all data)
1.063
a
b
2
c
2
R1(F) = g(|Fo| 2 |Fc|)/g|Fo| for the observed reflections [F2 . 2s(F2)]. wR2(F2) = {g[w(Fo 2 Fc2)2]/gw(Fo2)2}1/2
p)}1/2 (n = number of reflections, p = number of parameters).
.
S = {g[w(Fo 2 Fc2)2]/(n 2
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with an angle of 95.83(4)u, two crystallographically distinct Cu–
Table 3 List of selected bond distances [Å] and angles [u] for cooper compounds
3, 8, 9 and 10
Cl distances (Table 3) and a Cu–Cu distance of 3.736 Å. The L1
ligand is coordinated to copper in
a bidentate mode.
Compound 3
Consequently, the Cu atom is placed in a Cl3N2 distorted
square-based pyramid environment, generated by three
chloride [Cl1, Cl2 and Cl1i] ligands and two nitrogens [N2
and N4] belonging to the L1 ligand. The N4 atom deviates from
the N2–Cl1–Cl2 basal plane by 0.940 Å, while the copper atom
deviates slightly from this plane by 0.080 Å. The apical position
is occupied by one bridging Cl1i ligand 2.544 Å from the basal
plane. The angles around the metal centre vary from 88.19(12)u
to 105.27(4)u (Table 1), the shortest value pertaining to the
intraligand N2–Cu1–N4 angle. The Cl2–Cu1–Cl1i angle
[105.27(4)u, where Cl1i is in the apical position; symmetry
code: 2x + 1/2, 2y + 1/2, 2z + 1] deviates significantly from the
ideal value. The Cu1–N2 bond [2.014(3) Å] is slightly shorter
than the Cu1–N4 one [2.036(3) Å], a fact that suggests a higher
degree of covalence of the former. Compound 10 crystallizes
from DMF in the orthorhombic space group Pbca and its
asymmetric unit contains one [(CuCl)2(L1)DMF] molecule. As
Cu(1)–N(2)
Cu(1)–N(4)
Cu(1)–P(1)
Cu(1)–P(2)
N(4)–Cu(1)–P(2)
2.096(4)
2.166(4)
2.2476(12) N(4)–Cu(1)–P(1)
2.2903(12) N(2)–Cu(1)–P(2)
100.26(11) P(1)–Cu(1)–P(2)
N(2)–Cu(1)–N(4)
N(2)–Cu(1)–P(1)
94.31(14)
116.42(11)
113.35(11)
103.41(11)
124.07(5)
Compound 8
Cu(1)–O(1)
Cu(1)–N(3)
Cu(1)–N(7)
Cu(1)–N(1)
1.983(2)
1.999(3)
2.010(3)
2.014(3)
2.212(3)
91.39(10)
93.17(9)
100.37(10)
O(1)–Cu(1)–N(3)
O(1)–Cu(1)–N(7)
N(3)–Cu(1)–N(7)
O(1)–Cu(1)–N(1)
N(3)–Cu(1)–N(1)
N(7)–Cu(1)–N(5)
N(1)–Cu(1)–N(5)
87.99(10)
90.29(10)
170.17(11)
168.42(10)
88.41(11)
89.38(10)
98.30(10)
Cu(1)–N(5)
N(7)–Cu(1)–N(1)
O(1)–Cu(1)–N(5)
N(3)–Cu(1)–N(5)
Compound 9
Cu(1)–N(2)
Cu(1)–N(4)
Cu(1)–Cl(2)
Cu(1)–Cl(1)
Cu(1)–Cl(1)#1
Cl(1)–Cu(1)#1
2.014(3)
2.036(3)
2.2453(11) N(4)–Cu(1)–Cl(2)
2.2629(10) N(2)–Cu(1)–Cl(1)
2.7522(11) N(4)–Cu(1)–Cl(1)
2.7522(11) Cl(2)–Cu(1)–Cl(1)
N(2)–Cu(1)–N(4)
N(2)–Cu(1)–Cl(2)
88.19(12)
90.39(9)
156.91(11)
173.90(9)
89.71(9)
shown the Fig. 1d, the Cu(II) adduct 10 is a neutral
93.79(4)
mononuclear five-coordinated molecule in a square-based
pyramid geometry, where L1 is coordinated to copper in a
bidentate mode. Accordingly, the Cu atom is placed in a
Cl2N2O distorted square-based pyramid environment gener-
ated by two chloride [Cl1 and Cl2] ligands, two nitrogens [N2
and N4] belonging to the L1 ligand and one oxygen from a
DMF molecule. The Cl1 ligand deviates from the basal plane
N2–N4–O1 of 0.650 Å, while the copper atom deviates
somewhat from this plane by 0.231 Å. The apical position is
occupied by one Cl2 ligand 2.685 Å from the basal plane. The
angles around the metal centre vary from 83.77(6)u to
109.79(2)u (Table 1), the shortest value pertaining to the
interligand N2–Cu1–O1 angle. The Cl1–Cu1–Cl2 angle
[109.79(2)u, where Cl2 is in the apical position] deviates
significantly from the ideal value. The Cu1–N2 bond
[2.0708(17) Å] is comparable to the Cu1–N4 one [2.0407(16)
Å], a fact that suggests a similar degree of covalence in both.
In the crystals of both 9 and 10, the adjacent [CuCl2(L1)]2 or
[(CuCl)2(L1)DMF] molecules, respectively, are stacked in an
edge-to-face fashion between the centroid of one phenyl–
pyrazolyl ring and the hydrogen atom of the neighbouring
phenyl–pyrazolyl ring, and in a face-to-face fashion between
the centroids of neighbouring phenyl–pyrazolyl rings, with
separations of 3.014 Å and 3.814 Å, respectively for 9 and
3.311 Å and 3.545 Å, respectively for 10. The combination of
these aromatic interactions arranges the Cu(II) dimers 9 into a
three-dimensional network, in the same way as the Cu(II)
monomers 10.
N(2)–Cu(1)–Cl(1)#1 90.44(9)
N(4)–Cu(1)–Cl(1)#1 97.79(10)
Cl(2)–Cu(1)–Cl(1)#1 105.27(4)
Symmetry transformations used to generate equivalent atoms: #1 2x
+ 1/2, 2y + 1/2, 2z + 1.
Cl(1)–Cu(1)–Cl(1)#1 84.17(4)
Cu(1)–Cl(1)–Cu(1)#1 95.83(4)
Compound 10
Cu(1)–O(1)
Cu(1)–N(4)
Cu(1)–N(2)
1.9824(14) O(1)–Cu(1)–N(4)
2.0407(16) O(1)–Cu(1)–N(2)
2.0708(17) N(4)–Cu(1)–N(2)
165.27(6)
83.77(6)
88.30(6)
90.40(5)
90.44(5)
99.41(5)
109.79(2)
Cu(1)–Cl(1)
Cu(1)–Cl(2)
N(2)–Cu(1)–Cl(1)
O(1)–Cu(1)–Cl(2)
N(4)–Cu(1)–Cl(2)
2.2633(6)
2.4603(5)
150.58(5)
94.07(5)
99.47(5)
O(1)–Cu(1)–Cl(1)
N(4)–Cu(1)–Cl(1)
N(2)–Cu(1)–Cl(2)
Cl(1)–Cu(1)–Cl(2)
cules are stacked in an offset face-to-face fashion, with
separations of 4.329 Å between the centroids of one phenyl
ring from an equatorial indazolyl moiety with another phenyl
ring from a neighbouring trans equatorial indazolyl moiety.
This weak intermolecular p–p aromatic interaction helps to
arrange the copper complex 3 into a three-dimensional array.
Crystal structure of 9 and 10
The crystals obtained from the reaction of CuCl2 with the L1
ligand were dependent on the coordinating ability of the
solvent employed.27 When the solvent was CH3CN or CH3OH,
we obtained the dinuclear [CuCl2(L1)]2, 9, whereas by using a
strongly coordinating solvent, such as the DMF, we obtained
the monomer [(CuCl)2(L1)DMF], 10, in which DMF is
coordinated to the metal ion. Compound 9 crystallizes from
CH3CN in the monoclinic space group C2/c and its asymmetric
unit contains half a [CuCl2(L1)]2 molecule such that 9 is a
neutral dinuclear derivative, comprising two mononuclear
copper(II) subunits (Fig. 1c). A center of symmetry lies half-way
between the two copper atoms, relating one half of the
molecule to the other. Dimerization of the monocopper core
generated Cu1–Cl1–Cui (i symmetry: 2x + 1/2, 2y + 1/2, 2z + 1)
Crystal structure of 11 and 12
Colourless crystals of 11 and 12 suitable for single-crystal X-ray
diffraction analysis were obtained from acetonitrile by slow
evaporation at room temperature. Both compounds 11 and 12
crystallize in the monoclinic space group P21/c, with one
independent molecule in the asymmetric unit. Although they
do not have the same cell metric, their asymmetric unit
contains the same atomic composition of C30H24AgN9O3.
Therefore, the marked differences in the silver nitrate species
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11 and 12 are imposed by the different ligand, L1 and L2. In
fact, the asymmetric unit of 11 contains one silver nitrate salt,
i.e. one cationic [Ag(L1)2]+ molecule (Fig. 2a), and one free
NO32. On the other hand, the asymmetric unit in 12 contains
one [AgNO3(L2)2] molecule. The Ag(I) cation of 11 displays a
distorted tetrahedral geometry coordinated by four nitrogen
atoms from two L1 ligands, with N–Ag–N angles ranging from
86.38(7)u and 86.66(7)u for the intraligand angles and to
103.41(6)u and 106.95(7)u for the interligand angles (Table 4).
The Ag–N bond distances [range from 2.291(2) Å to 2.439(2) Å]
compare well with those observed in other four-coordinated
silver(I) bis(pyrazolyl)methanes complexes.28–30 The Ag(I)
cation of 12 also displays a distorted tetrahedral geometry
coordinated by three nitrogen atoms from two L2 ligands (one
indazolyl moiety from one L2 is not bound to silver) and one
oxygen atom from a monodentate nitrate anion. The N–Ag–N
angles range from 85.05(7)u for the intraligand angle to
110.80(6)u for the interligand angle. The N–Ag–O angles range
from 93.95(6)u to 107.38(6)u (Table 4). The Ag–N bond
distances [ranging from 2.1944(16) Å to 2.416(2) Å] and Ag–O
bond distance [(2.5334(16) Å] compare well with those
observed in other analogous silver(I) complexes.28–30 The
adjacent cationic [Ag(L1)2]+ molecules in 11 and the
[AgNO3(L2)2] molecules in 12 are stacked in a face-to-face
fashion with an average separation of 3.696 Å and 4.129 Å,
respectively between the centroids of the phenyl and pyrazolyl
rings from anti-parallel neighbouring indazolyl moieties. In
addition, 12 also presents p-stacking interactions of edge-to-
…
face fashion with a separation of 3.669 Å, a classic Ph–H p–Ph
type between nearly perpendicular neighbouring pyrazolyl
rings, and others of 3.607 Å between the p-electron clouds of
one oxo group from the nitrate ligands and the nearly
perpendicular neighbouring pyrazolyl rings from the indazolyl
moieties. The combination of these aromatic interactions
arranges the cationic [Ag(L1)2]+ molecules in 11 and the
[AgNO3(L2)2] molecule in 12 into a three-dimensional network.
Crystal structure of 13(a and b) and 14
Good colourless crystals of 13 and 14 were obtained from
methanol by slow evaporation at room temperature. These two
silver dinuclear derivatives 13(a and b) and 14 present a rare
coordination mode30 in which the two silver atoms, bridged by
…
the ligand, show
a short argentophilic Ag Ag contact.
¯
Compound 13 crystallizes in the triclinic space group P1 and
its asymmetric unit contains one dinuclear [Ag(O2CCF3)(L1)]2
complex with L1 and a bidentate trifluoroacetate bridging
adjacent silver atoms, another L1 ligand coordinating only one
silver atom and the second trifluoroacetate, disordered in two
positions, showing both monodentate (13a) and bidentate
(13b) coordinating modes (Fig. 2c and 2d respectively). The
–CF3 group from the bridging bidentate trifluoroacetate ligand
appears disordered and it is modelled in three positions with
identical occupation. Compound 14 crystallizes in the tetra-
gonal space group P41212. The structure displays a C2
symmetry because its asymmetric unit contains only half a
dinuclear [Ag(O2CCF3)(L2)]2 complex (Fig. 2e) and shows one
silver atom, two half bridging L2 ligands and one monodentate
trifluoroacetate ligand [the –CF3 group appears disordered and
it was modelled in two positions that were refined with
Fig. 2 Molecular views of silver compounds 11 (a), 12 (b), 13a (c), 13b (d), 14
(e), 15 (f) and 16 (g). The displacement ellipsoids are drawn at the 30%
probability level. All H atoms are omitted for clarity.
complementary occupancy factors, 0.401/0.599(8)]. The two-
fold C2 axis is located in such a way that it perpendicularly
i
…
bisects the Ag Ag line (i symmetry: 2y + 1, 2x + 1, 2z + 3/2).
In the dinuclear complex 13(a and b), one silver centre displays
a highly tetrahedral geometry with N–Ag–N angles around Ag1
ranging from 88.6(3)u for the intraligand angle to 108.0(3)u for
the interligand angle (Table 4). The other silver adjacent Ag2
exhibits different, highly distorted trigonal coordination with
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N–Ag–O angles in the range of 78.0(5)u (13b), 121.6(6)u (13a
and b) to 145.6(2)u and O–Ag–O angles ranging from 45.8(7)
(13b), 92.4(6)u (13a and b) to 136.2(5)u, associated with a short
Table 4 List of selected bond distances [Å] and angles [u] for silver compounds
11, 12, 13a, 13b, 14, 15 and 16
…
Compound 11
Ag(1)–N(8)
Ag(1)–N(2)
Ag(1)–N(6)
Ag(1)–N(4)
N(2)–Ag(1)–N(4)
Ag1 Ag2 contact of 3.0199(10) Å. Otherwise, in the dinuclear
2.292(2)
2.3045(19) N(8)–Ag(1)–N(6)
2.4150(19) N(2)–Ag(1)–N(6)
2.439(2)
86.66(7)
N(8)–Ag(1)–N(2)
152.45(7)
86.38(7)
103.41(6)
106.95(7)
129.87(7)
complex 14, both silver centres (related by C2 symmetry)
exhibit a highly distorted trigonal coordination with a N–Ag–N
angle of 108.27(9)u and N–Ag–O angle ranging from 111.18(9)u
N(8)–Ag(1)–N(4)
N(6)–Ag(1)–N(4)
i
…
to 140.53(9)u, associated with a short Ag Ag contact of
2.9840(5) Å. The N–Ag and O–Ag bond distances [in the range
of 2.132(18) Å–2.439(2) Å] for both compounds 13(a and b) and
14 compare well with those observed in other tetracoordinated
silver(I) bis(pyrazolyl)methanes complexes.28–30 The adjacent
dinuclear molecules 13(a and b) and 14 are staked in a face-to-
face fashion with separations of 3.782 Å [13(a and b)] and of
3.805 Å (14) between the centroids of one phenyl ring from an
indazolyl moiety with one pyrazolyl ring from a neighbouring
antiparallel indazolyl moiety. These weak intermolecular p–p
aromatic interactions help to arrange these dinuclear silver
complexes into a three-dimensional array.
Compound 12
Ag(1)–N(5)
Ag(1)–N(1)
2.1944(16) N(5)–Ag(1)–N(1)
2.2357(17) N(5)–Ag(1)–N(3)
157.66(7)
110.80(6)
85.05(7)
Ag(1)–N(3)
2.416(2)
N(1)–Ag(1)–N(3)
Ag(1)–O(1)
N(1)–Ag(1)–O(1)
N(3)–Ag(1)–O(1)
2.5334(16) N(5)–Ag(1)–O(1)
95.97(6)
119.65(13)
93.95(6)
N(9)–O(1)–Ag(1)
107.38(6)
Compound 13(a and b)
Ag(1)–N(6)
Ag(1)–N(4)
Ag(1)–N(2)
Ag(1)–O(1)
Ag(1)–Ag(2)
Ag(2)–O(4A)
Ag(2)–N(8)
Ag(2)–O(2)
Ag(2)–O(4B)
Ag(2)–O(3B)
2.243(7)
N(6)–Ag(1)–N(4)
N(6)–Ag(1)–N(2)
N(4)–Ag(1)–N(2)
N(6)–Ag(1)–O(1)
146.2(3)
108.0(3)
88.6(3)
91.4(2)
117.9(2)
91.7(2)
110.65(16)
70.5(2)
135.85(18)
67.12(15)
94.4(5)
2.259(8)
2.441(7)
2.531(6)
3.0199(10) N(4)–Ag(1)–O(1)
2.132(18) N(2)–Ag(1)–O(1)
2.284(8)
2.298(6)
2.496(17) N(2)–Ag(1)–Ag(2)
2.567(17) O(1)–Ag(1)–Ag(2)
Crystal structure of 15 and 16
N(6)–Ag(1)–Ag(2)
N(4)–Ag(1)–Ag(2)
Colourless crystals of 15 and 16 suitable for single-crystal X-ray
diffraction were grown from methanol by slow solvent
evaporation at room temperature. These two complexes,
derived from silver methanesulfonate, present a very different
structure depending on the L ligand employed. Compound 15
crystallizes in the monoclinic space group C2/c (Table 2). The
asymmetric unit contains one and a half molecules of the
[Ag(L1)2]+CH3SO32 salt (Fig. 2f) and this structure displays a C2
symmetry. The two-fold axis is located in such a way that it
passes through the Ag(2) atom belonging to half a cationic
[Ag(L1)2]+ molecule. Therefore, the rotation of 180u around this
C2 axis of the half cationic [Ag(L1)2]+ molecule and of the half
O(4A)–Ag(2)–N(8) 121.6(6)
O(4A)–Ag(2)–O(2) 92.4(6)
O(2)–Ag(2)–O(3B)
O(4B)–Ag(2)–O(3B)
O(4A)–Ag(2)–Ag(1)
N(8)–Ag(2)–Ag(1)
O(2)–Ag(2)–Ag(1)
O(4B)–Ag(2)–Ag(1)
O(3B)–Ag(2)–Ag(1)
O(3B)–Ag(2)–Ag(1)
46.5(6)
N(8)–Ag(2)–O(2)
145.6(2)
126.8(6)
77.75(17)
77.59(17)
133.7(6)
119.2(5)
119.2(5)
O(4A)–Ag(2)–O(4B) 45.8(7)
N(8)–Ag(2)–O(4B) 78.0(5)
O(2)–Ag(2)–O(4B) 136.2(5)
O(4A)–Ag(2)–O(3B) 8.4(10)
N(8)–Ag(2)–O(3B) 118.6(5)
Compound 14
Ag(1)–N(3)
Ag(1)–N(1)
Ag(1)–O(1)
Ag(1)–Ag(1)#1
2.248(2)
2.274(3)
2.304(3)
2.9840(5) N(3)–Ag(1)–Ag(1)#1
O(1)–Ag(1)–Ag(1)#1
N(3)–Ag(1)–N(1)
N(3)–Ag(1)–O(1)
N(1)–Ag(1)–O(1)
108.27(9)
140.53(9)
111.18(9)
105.59(7)
78.24(8)
2
free CH3SO3 anion generates, by symmetry, a complete
2
cationic moiety and another half free CH3SO3 anion. Both
N(1)–Ag(1)–Ag(1)#1 83.09(6)
Symmetry transformations used to generate equivalent atoms: #1 2y
+ 1, 2x + 1, 2z + 3/2.
pairs of cations and anions of 15 are chemically equivalent but
symmetrically independent. The coordination sphere of the
silver atoms is formed by four N atoms of two L1 ligands. The
angles around the central silver(I) cations indicate that they
are in a highly distorted tetrahedral coordination. The N(2)–
Ag(1)–N(6) angle = 157.03(18)u and shows the largest deviation
from idealized tetrahedral angle, whereas the smallest devia-
tion is shown by N(2)–Ag(1)–N(4) = 86.01(17)u (Table 4). The
Compound 15
Ag(1)–N(2)
Ag(1)–N(6)
Ag(1)–N(8)
2.250(5)
2.258(5)
2.521(6)
2.551(5)
2.268(5)
2.268(5)
2.416(6)
2.416(6)
N(6)–Ag(1)–N(8)
N(2)–Ag(1)–N(4)
N(6)–Ag(1)–N(4)
N(8)–Ag(1)–N(4)
N(10)#1–Ag(2)–N(10)
N(10)#1–Ag(2)–N(12)#1 122.02(19)
N(10)–Ag(2)–N(12)#1
N(10)#1–Ag(2)–N(12)
86.24(18)
86.01(17)
101.28(17)
129.88(18)
134.8(3)
Ag(1)–N(4)
Ag(2)–N(10)#1
Ag(2)–N(10)
Ag(2)–N(12)#1
Ag(2)–N(12)
N(2)–Ag(1)–N(6)
N(2)–Ag(1)–N(8)
87.06(18)
87.06(18)
122.02(19)
103.0(3)
Ag–N
bond
lengths
are
comparable
to
other
[Ag(bis(pyrazolyl)methane)2] complexes.28–30 Compound 16
157.03(18) N(10)–Ag(2)–N(12)
105.90(19) N(12)#1–Ag(2)–N(12)
¯
crystallizes in the triclinic space group P1 (Table 2) and
Symmetry transformations used to generate equivalent atoms: #1 2x
+ 1, y, 2z + 1/2.
displays crystallographic inversion symmetry, developing a
polymeric arrangement in the solid state. The whole structure
consists of an infinite linear chain of the asymmetric unit
[Ag(OSOCH3O)(0.5L2)2]. This motif is repeated indefinitely
along the crystallographic a axis by the inversion symmetry
and translation operations to generate the polymeric structure
[Ag(OSOCH3O)(0.5L2)2]n (Fig. 2g). The asymmetric unit con-
sists of half a centrosymmetric dimer in which the silver atoms
are bridged by oxygen atoms from two methanesulfonate
groups, resulting in a distorted eight-membered ring, with O–
S–O bridge angles of 112.66(12)u and O–Ag–Oi (i symmetry: 2x
+ 1, 2y, 2z + 1) angles 117.99(6)u, analogous to other similar
eight-membered silver dimers.31 Two additional coordination
Compound 16
Ag(1)–N(3)
Ag(1)–N(1)
Ag(1)–O(2)#1
Ag(1)–O(1)
2.201(2)
2.201(2)
2.5170(19) N(1)–Ag(1)–O(2)#1
2.526(2) N(3)–Ag(1)–O(1)
N(3)–Ag(1)–N(1)
N(3)–Ag(1)–O(2)#1
137.67(7)
112.22(7)
90.52(7)
89.51(7)
S(1)–O(3)
S(1)–O(2)
S(1)–O(1)
S(1)–C(16)
O(2)–S(1)–O(1)
O(3)–S(1)–C(16)
O(2)–S(1)–C(16)
1.4530(19) N(1)–Ag(1)–O(1)
1.4574(19) O(2)#1–Ag(1)–O(1)
111.41(7)
117.99(6)
112.59(11)
112.51(12)
106.28(16)
108.18(10)
109.06(10
1.458(2)
1.764(3)
O(3)–S(1)–O(2)
O(3)–S(1)–O(1)
112.66(12) O(1)–S(1)–C(16)
105.61(16) S(1)–O(1)–Ag(1)
106.52(15) S(1)–O(2)–Ag(1)#1
Symmetry transformations used to generate equivalent atoms: #1 2x
+ 1, 2y, 2z + 1.
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Table 5 List of selected bond distances [Å] and angles [u] for silver compounds
17(a and b), 19 and 21
Compound 17(a and b)
Ag(1)–N(2)
2.230(3)
2.263(3)
2.381(3)
2.462(3)
2.263(3)
2.312(3)
2.328(3)
2.461(3)
153.56(12)
112.66(11)
N(2)–Ag(1)–N(8)
N(2)–Ag(1)–N(6)
N(8)–Ag(1)–N(6)
N(2)–Ag(1)–O(1)
N(8)–Ag(1)–O(1)
N(6)–Ag(1)–O(1)
N(12)–Ag(2)–N(10)
N(14)–Ag(2)–N(16)
N(12)–Ag(2)–N(16)
N(10)–Ag(2)–N(16)
139.27(10)
109.50(10)
89.93(10)
97.65(9)
110.98(10)
106.55(10)
84.97(11)
84.46(11)
97.71(11)
133.41(11)
Ag(1)–N(8)
Ag(1)–N(6)
Ag(1)–O(1)
Ag(2)–N(14)
Ag(2)–N(12)
Ag(2)–N(10)
Ag(2)–N(16)
N(14)–Ag(2)–N(12)
N(14)–Ag(2)–N(10)
Compound 19
Ag(1)–N(6)
Ag(1)–N(2)
Ag(1)–N(8)
Ag(1)–N(4)
2.297(2)
2.306(2)
2.391(2)
2.414(2)
87.27(7)
N(6)–Ag(1)–N(2)
N(6)–Ag(1)–N(8)
N(2)–Ag(1)–N(8)
N(6)–Ag(1)–N(4)
N(8)–Ag(1)–N(4)
148.04(8)
86.59(8)
103.25(8)
110.34(8)
128.83(8)
N(2)–Ag(1)–N(4)
Compound 21
Ag(1)–N(6)
Ag(1)–N(4)
Ag(1)–N(8)
Ag(1)–N(2)
2.299(2)
2.311(2)
2.376(2)
2.398(2)
87.50(8)
N(6)–Ag(1)–N(4)
N(6)–Ag(1)–N(8)
N(4)–Ag(1)–N(8)
N(6)–Ag(1)–N(2)
N(8)–Ag(1)–N(2)
146.81(9)
86.65(8)
104.18(8)
109.77(8)
129.75(9)
Fig. 3 Molecular views of silver compounds 17a (a), 17b (b), 19 (c) and 21 (d).
The displacement ellipsoids are drawn at the 30% probability level. All H atoms
are omitted for clarity.
N(4)–Ag(1)–N(2)
sites on each silver centre are occupied by two N atoms from
two different L2 ligands (Fig. 2g), which in turn bridge the two
other N to silver atoms of adjacent motifs. The silver atoms
exhibit a highly distorted tetrahedral coordination. The N(3)–
Ag(1)–N(1) angle = 137.67(7)u and shows the largest deviation
from the idealized tetrahedral angle, whereas the smallest
deviation is shown by N(3)–Ag(1)–O(1) = 89.51(7)u (Table 4).
The adjacent [Ag(L1)2]+ cation in 15 and the motifs in 16 are
stacked in a face-to-face fashion with a separation of 3.748 Å
and 3.712 Å, respectively between the centroids of the anti-
parallel neighbouring indazolyl moieties and also in an edge-
to-face fashion with a separation of 2.880 Å and 3.173 Å,
respectively between a hydrogen of a phenyl ring with a
pyrazolyl ring from the perpendicular neighbouring indazolyl
moiety.
N(14)–Ag(2)–N(12) angle = 153.56(12)u in 17b and shows the
largest deviation from the idealized tetrahedral angle, whereas
the smallest deviation is shown by N(6)–Ag(1)–N(8) = 86.59(8)u
in 19 (Table 5). The adjacent cationic [Ag(L1)2]+ molecules in 19
and 21 are stacked in a face-to-face fashion with a separation
of 3.680 Å and 3.770 Å, respectively between the centroids of
the anti-parallel neighbouring indazolyl moieties and also in
an edge-to-face fashion with a separation of 2.850 Å in 21 and
3.007 Å in 17 respectively, between an H atom of a phenyl ring
with a pyrazolyl ring from the perpendicular neighbouring
indazolyl moiety. The combination of these aromatic interac-
tions arrange the cationic [Ag(L1)2]+ and neutral
[AgCF3SO3(L1)2] molecules a three-dimensional network.
Crystal structure of 23 and 24
Red crystals of 23 and 24 suitable for single-crystal X-ray
diffraction were grown from acetonitrile by slow solvent
evaporation at ambient temperature. Compound 23 crystal-
Crystal structure of 17(a and b), 19 and 21
Colourless crystals of 17, 19 and 21 suitable for single-crystal
X-ray diffraction analysis were obtained from acetonitrile by
slow evaporation at ambient temperature. Compound 17
¯
lizes in the triclinic space group P1, while compound 24
crystallizes in the orthorhombic space group P212121.
However, in both crystals, the asymmetric unit contains one
[AuCl2(L)]+ cation (Fig. 4, L = L1, 23 and L = L2, 24) and one
[AuCl4]2 counterion. Furthermore, in 24 the asymmetric unit
presents two acetonitrile crystallization molecules.
¯
crystallizes in the triclinic space group P1 while both
compounds 19 and 21 crystallize in the monoclinic space
group P21/c (Table 2). The asymmetric unit for each of these
three crystals contains a similar [Ag(L1)2]+ cation accompanied
by one free anionic molecule: [CF3SO3]2, 17b; [ClO4]2, 19 and
[BF4]2, 21 (Fig. 3). Furthermore, the asymmetric unit of 17
contains a neutral [AgCF3SO3(L1)2] molecule, 17a. The coordi-
nation spheres of the silver atoms in all the cationic 17b, 19
and 21 compounds are formed by four N atoms of two L1
ligands, except in the neutral 17a compound, where one of the
N atoms is replaced by one O atom from a monodentate
trifluoromethanesulfonate ligand. The angles around the
central silver(I) atom for 17a, 17b, 19 and 21 indicate that
they are in a highly distorted tetrahedral coordination. The
In both the [AuCl2(L)]+ cations, the square planar gold(III)
atom is bound to two N atoms belonging to the L ligand and
two Cl ligands. With regard to the geometry, in both cations
the angles between the ligands surrounding the gold in the
cationic square plane do not deviate significantly from their
ideal values of 180u and 90u (Table 6). The same is true for the
anionic square planar [AuCl4]2 counterion in both 23 and 24,
in which the gold(III) is surrounded by four Cl ligands. All the
Au–N bond distances in both compounds [2.009(6) Å to
2.035(6) Å] are comparable to the average Au–N bond distance
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stacked cationic [AuCl2(L)]+ as one-dimensional zig-zag chains
extending along the b axis in 24 and the c axis in 23.
Conclusions
We have reported the synthesis and complete characterization
of novel Group 11 metal adducts containing two indazolyl-
based regioisomeric ligands, previously described in their
interaction with Group 12 metal acceptors.10 The composition
and geometry on the metal centres has been determined by a
combination of NMR (apart for the Cu(II) derivatives 5–10), IR
and ESI MS spectroscopies and mainly X-ray studies, which
confirmed the stoichiometries and the coordination modes of
the new di(indazolyl)methane ligands in their metal com-
plexes. Relevant differences between L1 and L2 have been seen
in derivatives 5–8 where, contrary to L1, the more hindered L2
ligand is able to displace a counter-ion from the copper
coordination sphere, affording 1 : 2 metal to ligand cationic
adducts 6 and 8. In the case of the bigger silver atom, such a
tendency seems reversed and the L1 adducts 11, 15, 17, 19 and
21 exist as 1 : 1 metal to ligand cationic complexes with ionic
counter-ions NO3, ClO4, BF4, SO3CH3 and SO3CF3, indepen-
dent to their donating ability, even if in the X-ray lattice of the
triflate adduct 17, two independent asymmetric units have
been found, one of them containing a weakly ligated triflate, a
chelating L1 molecule and a second monodentate L1 (see
Fig. 3a). In contrast, L2 displayed unexpected structural
features, mainly in derivatives 16 and 20, where the torsion
around the bridging methylene allowed L2 to act as a bridging
ligand with two different silver atoms, affording polynuclear
derivatives. It is noteworthy that in the case of silver(I)
trifluoroacetate, both the L1 and L2 adducts exist as dinuclear
complexes but in adduct 13, only one L1 is able to behave as a
bridging ligand, while in 14, both L2 ligands have been found
to act in a bridging mode after a torsional movement around
the bridging methylene. Only in a few cases, such as with
AgBF4 and AuCl3 acceptors, have similar adducts been
obtained, resembling each other both in the metal to ligand
ratio and in the geometry around the metal centre.
Fig. 4 Molecular views of the gold compounds 23 (a) and 24 (b). The
displacement ellipsoids are drawn at the 30% probability level. All H atoms are
omitted for clarity.
for similar compounds.32 All the Au–Cl bond distances for 23
and 24 in both the cations and anions are also similar to the
average Au–Cl bond distance of 2.28(3) Å. The adjacent
cationic [AuCl2(L1)]+ moiety in 23 is stacked in a face-to-face
fashion with a separation of 3.686 Å between the centroids of
the anti-parallel neighbouring indazolyl moieties and also in
an edge-to-face fashion with a separation of 2.902 Å between a
hydrogen of one phenyl ring from an indazolyl moiety with
one pyrazolyl ring from a perpendicular neighbouring inda-
zolyl moiety. The adjacent [AuCl2(L2)]+ in 24 is stacked in a
face-to-face fashion with a separation of 3.477 Å and 3.551 Å
between the centroids of the phenyl and pyrazolyl rings from
anti-parallel neighbouring indazolyl moieties. The crystal of 24
also presents noteworthy p-stacking interactions of an edge-to-
face fashion with a separation of 3.184 Å between the
p-electron clouds of the nitrile groups from the acetonitrile
molecules of crystallization and the nearly perpendicular
neighbouring pyrazolyl rings from the indazolyl moieties.
The combination of these aromatic interactions arranges the
Table 6 List of selected bond distances [Å] and angles [u] for the gold
compounds 23 and 24
Compound 23
Au(1)–N(4)
Au(1)–N(2)
2.032(3)
2.032(3)
N(4)–Au(1)–N(2)
N(4)–Au(1)–Cl(2)
N(2)–Au(1)–Cl(2)
N(4)–Au(1)–Cl(1)
N(2)–Au(1)–Cl(1)
Cl(2)–Au(1)–Cl(1)
Cl(4)–Au(2)–Cl(3)
Cl(4)–Au(2)–Cl(6)
Cl(3)–Au(2)–Cl(6)
Cl(4)–Au(2)–Cl(5)
89.20(11)
90.44(7)
179.39(9)
178.66(8)
90.01(8)
90.35(4)
88.98(4)
178.12(3)
90.29(4)
89.96(3)
In summary, we have demonstrated that L1 and L2 interact
with several Group 11 metal salts, yielding stable adducts with
different stoichiometries, mainly due to their very different
steric hindrance. An unexpected rotational ability around the
bridging methylene has been found in the bulky L2 ligand,
which allows it to act as a ditopic bridging donor in the
formation of inorganic polynuclear chains.
Au(1)–Cl(2)
Au(1)–Cl(1)
Au(2)–Cl(4)
Au(2)–Cl(3)
Au(2)–Cl(6)
Au(2)–Cl(5)
Cl(3)–Au(2)–Cl(5)
Cl(6)–Au(2)–Cl(5)
2.2470(8)
2.2535(9)
2.2624(9)
2.2741(9)
2.2828(9)
2.2906(9)
178.75(4)
90.79(3)
Compound 24
Au(1)–N(3)
Au(1)–N(1)
Au(1)–Cl(1)
Au(1)–Cl(2)
Au(2)–Cl(4)
Au(2)–Cl(5)
Au(2)–Cl(6)
Au(2)–Cl(3)
2.009(6)
2.035(6)
N(3)–Au(1)–N(1)
N(3)–Au(1)–Cl(1)
N(1)–Au(1)–Cl(1)
N(3)–Au(1)–Cl(2)
N(1)–Au(1)–Cl(2)
Cl(1)–Au(1)–Cl(2)
Cl(4)–Au(2)–Cl(5)
Cl(4)–Au(2)–Cl(6)
Cl(5)–Au(2)–Cl(6)
Cl(4)–Au(2)–Cl(3)
88.8(2)
178.16(19)
91.01(16)
90.51(18)
178.1(2)
89.62(7)
90.02(8)
178.60(8)
91.30(8)
90.01(8)
Acknowledgements
2.2642(18)
2.2710(18)
2.2769(19)
2.2785(17)
2.2793(18)
2.2859(18)
179.55(7)
88.67(8)
Financial support from the University of Camerino, the Junta
´
de Andalucıa (grant 2009/FQM-4826) and CSIC (grant PIF/
2008-017-1) is gratefully acknowledged. C. S. thanks the Junta
´
de Andalucıa for a predoctoral fellowship.
Cl(5)–Au(2)–Cl(3)
Cl(6)–Au(2)–Cl(3)
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