Copper(I) and silver(I) azide complexes containing N-donor ligands

Article abstract of DOI:10.1016/S0277-5387(01)00895-6

From the interaction of imidazole-type ligand L (L = imidazole (im), 1-methylimidazole (1-meim), 2-methylimidazole (2-meim), 4-methylimidazole (4-meim), benzimidazole (bzim), 1-benzylimidazole (bnim)) with [Cu(N₃)(PPh₃)₂]<

Full text of DOI:10.1016/S0277-5387(01)00895-6

Polyhedron 20 (2001) 2755–2763
www.elsevier.com/locate/poly
Copper(I) and silver(I) azide complexes containing N-donor
ligands
C. Pettinari *
Dipartimento di Scienze Chimiche, Uni6ersita` degli Studi di Camerino, 6ia S. Agostino 1, 62032 Camerino MC, Italy
Received 15 June 2001; accepted 18 July 2001
Abstract
From the interaction of imidazole-type ligand L (L=imidazole (im), 1-methylimidazole (1-meim), 2-methylimidazole (2-meim),
4-methylimidazole (4-meim), benzimidazole (bzim), 1-benzylimidazole (bnim)) with [Cu(N3)(PPh3)2]2 the new mononuclear
[Cu(N3)(PPh3)2(L)] and dinuclear [Cu2(N3)2(PPh3)3(L)] species have been obtained. Chelating bidentate ligands (L2=2,2-bipyridyl
(bipy), 1,10-phenanthroline (phen) or 2,9-dimethyl-1,10-phenanthroline (cupr)) react with [M(N3)(PPh3)2]2 (M=Cu or Ag)
yielding [M(N3)(PPh3)(L2)]. The S-donors 1-methyl-2-imidazol-2(3H)-thione (Hmimt), 2-benzothiazolethiol (Hbtt) and 2-
pyridinethiol (Hpyt) react with [Cu(N3)(PPh3)2]2 in ethanol undergoing deprotonation and yielding [Cu(mimt)(Ph3P)]n, [Cu(btt)]n
and [Cu(pyt)]n, respectively. On the contrary, Hmimt and imidazoline-2(1,3H)thione (Himt) react in diethyl ether with
[Cu(N3)(PPh3)2]2 yielding [Cu(N3)(Hmimt)3] and [Cu(N3)(PPh3)(Himt)], respectively. P(o-tolyl)3 is able to displace the less basic
phosphine PPh3 from [Cu(N3)(PPh3)(cupr)] yielding the complex [Cu(N3){P(o-tolyl)3}(cupr)]. 1,3-Bis(diphenylphosphino)propane
(dppp) reacts with [Cu(N3)(PPh3)(cupr)] yielding the complex [Cu2(N3)2(dppp)3]. [Cu(N3)(PPh3)2(im)] and [Cu(N3)(PPh3)(phen)]
react with CS2 in benzene, in presence of excess of PPh3 forming [Cu(SCN)(PPh3)2] and [Cu(tz)(PPh3)(phen)] (Htz=4-thia-1,2,3-
triazole-5-thione), respectively. [Ag(N3)(PPh3)(cupr)] reacts slowly with excess of CS2 in diethyl ether giving [Ag(tz)(cupr)],
whereas the same reaction in benzene in excess of PPh3 yields immediately [Ag(SCN)(PPh3)2]. From the reaction of
[Ag(N3)(PPh3)(cupr)] with cyCN the complex [Ag(N3)(cyCN)(PPh3)(cupr)] formed. All derivatives were characterized by IR and
1
far-IR data, conductivity, H NMR and in some cases also with 31P{1H} NMR and molecular weight measurements. © 2001
Elsevier Science Ltd. All rights reserved.
Keywords: Copper complexes; Silver complexes; Azole complexes; Phenanthroline; Spectroscopy
however, that the interaction between [MX(PR3)n] and
N-donor ligands can yield complexes characterized by
different stoichiometry, nuclearity and properties, also
depending on the nature of the counter-ions [7–10].
Despite the large number of known copper(II) azide
complexes [11], only a few papers have been published
dealing with analogous copper(I) and silver(I) systems,
although copper(I) azide phosphino complexes were
obtained as early as 1971 by Ziolo and coworkers [12]
with interest in this class of compounds continuing
thereafter with La Monica et al. [13] who investigated
the reactivity of the azido group bonded to copper.
Copper complexes containing both N-donor ligands
and azido groups also have been received recently
particular attention: for example, a new synthetic route
for designing homometallic chains of formula
[M(lig)(N3)2]n [M=Mn or Cu; lig=4,4-dimethyl-2,2%-
1. Introduction
Tertiary phosphine complexes of copper(I) have re-
ceived great attention [1]. They can be used as precur-
sors in chemical vapor deposition of copper films [2], as
reagents in metal cluster [3], metallaborane [4] and
organic chemistry [5]. Phosphine-ligated copper(I) com-
plexes are known to produce a diversity of stoi-
chiometries and structural prototypes which include
complexes with ligand to copper ratios 3:1, 3:2, 2:1, 4:2,
2:2 and 4:4 [1,6]. The stoichiometry of phosphine cop-
per(I) complexes depends primarily upon the steric bulk
of the phosphine ligand and to a lesser extent on the
choice of the counter-ion. We have recently found,
* Tel.: +39-0737-402-234; fax: +39-0737-402-217.
E-mail address: pettinar@camserv.unicam.it (C. Pettinari).
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(01)00895-6

2756
C. Pettinari / Polyhedron 20 (2001) 2755–2763
bipyridine], exhibiting alternating ferromagnetic and
antiferromagnetic properties, has been recently pro-
posed [14].
2002w (N3), 1654w, 1584w, 1570w, (C···C, C···N),
524m, 507s, (PPh), 439m, 424m, 279w, 255w (lazole
,
CuꢀN). Elemental analysis: Anal. Found: C, 68.88; H,
Following a line of research whose major target is the
chemical and structural characterization of Group 11
metal complexes containing N-donor ligands, struc-
turally analogues of biologically important organic nu-
cleobases, we have reported earlier the synthesis,
structural and spectroscopic investigation of several
triorganophosphine copper(I) and silver(I) containing
halide or oxyanions [7–10]. As a part of these studies
we were interested in extending the available literature
data to include complexes incorporating N-donor,
phosphine and the azide ligand.
5.01; N, 6.51. Calc. for C36H30N3P2Cu: C, 68.62; H,
4.80; N, 6.67%.
\
(CH2Cl2, conc.=1.0×10−3
m
mol l−1): 2.2 V−1 mol2 cm−1
.
2.2.2. [Cu(N3)(PPh3)2(im)] (1)
A solution/suspension of im (0.13 g, 1.9 mmol) in
diethyl ether (30 ml) was added to [Cu(N3)(PPh3)2]
(0.30 g, 0.48 mmol) in diethyl ether (40 ml) at 273 K.
After the addition the suspension was stirred overnight
at r.t., then filtered off and the colorless precipitate
washed with 40 ml of diethyl ether–ethanol (3:1) and
shown to be compound 1. Recrystallized from acetoni-
trile–diethyl ether (1:1) (0.29 g, 0.4 mmol, yield 83%);
1
2. Experimental
m.p. 168–170 °C. H NMR (CDCl3, 293 K): l 6.9 (s
br, 1H, H4+H5), 7.5 (s br, 2H, H2), 7.3 (m, 30H,
Harom). 31P{1H} NMR (CDCl3, 293 K): l −2.4s.
31P{1H} NMR (CDCl3, 218 K): l −4.2s. IR (Nujol
mull, cm−1): 3150–2950br (NꢀH), 3120w, 3080w,
3050w (CꢀHazole+CꢀHarom), 2056s (N3), 1618w, 1570w,
1560w, 1530m (C···C, C···N), 524m, 513s, 505s (PPh),
2.1. General procedures
All reactions were carried out under an atmosphere
of dry-oxygen free dinitrogen, using Schlenk tech-
niques. Solvents were freshly distilled over an appropri-
ate drying agent and further degassed before use where
necessary. In some cases, as necessary, the reactions
were protected from light by covering the reaction
vessels with aluminum foil. Concentration was always
carried out in vacuo (water aspirator). The samples for
microanalysis were dried in vacuo to constant weight
[20 °C, approximately 0.1 Torr (13.3 Pa)]. Elemental
analyses (C, H, N, S) were performed with a Fison
Instruments 1108 CHNS-O Elemental Analyzer. The
IR spectra were recorded from 4000 to 150 cm−1 with
a Perkin–Elmer System 2000 FT-IR instrument. 1H
and 31P NMR spectra in a VXR-300 Varian spectrome-
ter operating at room temperature (r.t.) (300 MHz for
1H and 121.4 MHz for 31P). Abbreviations: s=singlet,
m=multiplet, d=doublet, dd=double doublet, t=
triplet, br=broad. Relative intensity of signals in
square brackets.
398w, 376w, 353w, 324w, 303w, 279w, 274 (lazole
,
CuꢀN). Elemental analysis: Anal. Found: C, 66.88; H,
5.11; N, 10.42. Calc. for C39H34N5P2Cu: C, 67.09; H,
4.91; N, 10.03%. \m (acetone, conc.=1.0×10−3
mol l−1): 19.3 V−1 mol2 cm−1
.
2.2.3. [Cu(N3)(PPh3)2(1-meim)] (2)
This compound has been obtained as 1 (yield 62%);
1
m.p. 134–136 °C. H NMR (CDCl3, 293 K): l 3.75 (s
br, 3H, CH3), 6.9 (s br, 2H, H4+H5), 7.3 (m, 30H,
Harom), 7.6 (s br, 1H, H2). 31P{1H} NMR (CDCl3, 293
K): l −3.8s. 31P{1H} NMR (CDCl3, 218 K): l −4.1s
br. IR (Nujol mull, cm−1): 3180w (CꢀHarom), 2029m,
2017m (N3), 1684w, 1654w, 1646w, 1570w, 1522w,
1508w (C···C, C···N), 526w, 514s, 504m, 493m (PPh),
445w, 419w, 373w, 335w, 303w, 281w, 254w, 247w
(lazole, CuꢀN). Elemental analysis: Anal. Found: C,
66.99; H, 5.11; N, 9.93. Calc. for C40H36N5P2Cu: C,
67.45; H, 5.09; N 9.84%. \m (CH2Cl2, conc.=1.2×
10−3 mol l−1): 1.2 V−1 mol2 cm−1. MW (CHCl3,
0.40×10−3 mol l−1): 288.
2.2. Syntheses
Safety note! Azide compounds are potentially explo-
sive and should be treated with care and in small
quantities.
2.2.4. [Cu(N3)(PPh3)2(2-meim)] (3)
The complexes [M(N3)(PPh3)2]2 (M=Cu or Ag) were
prepared in accordance with literature procedures [12].
This compound has been obtained as 1 (yield 83%);
m.p. 169–171 °C. H NMR (CDCl3, 293 K): 2.2 (s br,
1
3H, CH3), 6.9 (s br, 2H, H4+H5), 7.3 (m, 30H,
Harom), 7.7 (s br, 1H, NH). 31P{1H} NMR (CDCl3, 293
K): 0.75s br. 31P{1H} NMR (CDCl3, 218 K): −1.1s br.
IR (Nujol mull, cm−1): 3110w, 3080w (CꢀHarom),
3000–2500br (NꢀH) 2051m (N3), 1684w, 1670w,
1628w, 1616w, 1576w, 1540w, 1506w (C···C, C···N),
525w, 514s, 504s, 494s (PPh), 442w, 430w, 417w, 377w,
271w (lazole, CuꢀN). Elemental analysis: Anal. Found:
2.2.1. [Cu(N3)(PPh3)2]2
Recrystallised from chloroform–diethyl ether (yield
1
95%); m.p. 218–221 °C. H NMR (CDCl3, 293 K): l
7.2–7.4 (m br, 30H, Harom). 31P{1H} NMR (CDCl3, 293
K): l −2.1s. 31P{1H} NMR (CDCl3, 218 K): l 23.7s,
5.5s, 2.0s, −1.5s, −2.8s, −4.5s. IR (Nujol mull,
cm−1): 3050w (CꢀHazole+CꢀHarom), 2052s, 2029m,

C. Pettinari / Polyhedron 20 (2001) 2755–2763
2757
C, 67.32; H, 5.31, N, 9.97. Calc. for C40H36N5P2Cu: C,
(CDCl3, 293 K): l −0.7 (br). 31P{1H} NMR (CDCl3,
218 K): l 32.7s, 3.4s, 0.1s, −2.1s, −4.4s. IR (Nujol
mull, cm−1): 3060w (CꢀHarom), 2033s (N3), 1684w,
1670w, 1654w, 1636w, 1622m, 1582w, 1573m, 1509s
(C···C, C···N), 527s, 502s (PPh), 440m, 352w, 283m,
244m (lphen, CuꢀN). Elemental analysis: Anal. Found:
C, 65.43; H, 4.40; N, 12.71. Calc. for C30H23N5PCu: C,
65.75; H, 4.23; N, 12.78%. \m (acetone, conc.=0.9×
67.45; H, 5.09; N 9.84%. \m (acetone, conc.=0.9×
10−3 mol l−1): 4.2 V−1 mol2 cm−1
.
2.2.5. [Cu(N3)(PPh3)2(4-meim)] (4)
This compound has been prepared as 1 (yield 63%).
Washed with ethanol (10 ml); m.p. 174–177 °C. 1H
NMR (CDCl3, 293 K): l 2.2 (s br, 3H, CH3), 6.85 (s br,
1H, H5), 7.3 (m, 30H, Harom), 7.6 (s br, 1H, H2).
31P{1H} NMR (CDCl3, 293 K): l −2.4s. 31P{1H}
NMR (CDCl3, 218 K): l −4.4s br. IR (Nujol mull,
cm−1): 3050w (CꢀHarom), 2059s (N3), 1618w, 1584w,
1545w, 1508w (C···C, C···N), 513s, 504s, 492s (PPh),
442w, 418w, 367w, 277w (lazole, CuꢀN). Elemental
analysis: Anal. Found: C, 66.96; H, 5.23; N, 9.64. Calc.
for C40H36N5P2Cu: C, 67.45; H, 5.09; N 9.84%. \m
10−3 mol l−1): 16.2 V−1 mol2 cm−1
.
2.2.9. [Cu(N3)(PPh3)(cupr)] (8)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 1:1 (yield 94%); m.p.
1
235–238 °C. H NMR (CDCl3, 293 K): l 2.8 (s, 6H,
CH3), 7.1–7.5 (m br, Harom), 7.6 (d, 2H, CHcupr), 7.8 (s,
2H, CHcupr), 8.2 (d, 2H, CHcupr). 31P{1H} NMR
(CDCl3, 293 K): l −3.1br. 31P{1H} NMR (CDCl3, 218
K): l 23.7s, −2.7s, −4.5s. IR (Nujol mull, cm−1):
3040w (CꢀHarom), 2027s (N3), 1684w, 1588w, 1558w,
1507w (C···C, C···N), 527s, 509s, 494w (PPh), 487w,
440w, 419w, 275w (lcupr, CuꢀN). Elemental analysis:
Anal. Found: C, 66.79; H, 4.91; N, 11.86. Calc. for
C32H27N5PCu: C, 66.71; H, 4.72; N, 12.16%. \m
(acetone,
V
conc.=1.1×10−3
.
mol l−1):
6.9
−1 mol2 cm−1
2.2.6. [Cu(N3)(PPh3)2(bzim)] (5)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 1:1 (yield 54%); m.p.
1
157–160 °C. H NMR (DMSO-d6, 293 K): 7.15 (br,
33H, Harom+CHbzim), 7.3t (m, 2H, CHbzim). 31P{1H}
NMR (DMSO-d6, 293 K): l −26.34 [1], −3.3 br [20].
IR (Nujol mull, cm−1): 3110w (CꢀHarom), 3000–2400br
(NꢀH), 2037s (N3), 1684w, 1654w, 1622w, 1570w,
1560w, 1540w (C···C, C···N), 526w, 516s, 505m, 495m
(PPh), 476sh, 442w, 429m, 322w, 304w, 284w, 230w
(lazole, CuꢀN). Elemental analysis: Anal. Found: C,
68.66; H, 4.97; N, 9.51. Calc. for C43H36N5P2Cu: C,
69.02; H, 4.85; N, 9.36%. \m (CH2Cl2, conc.=1.0×
(CH2Cl2,
V
conc.=1.1×10−3
.
mol l−1):
5.4
−1 mol2 cm−1
2.2.10. [Cu(N3)(PPh3)(bipy)]·Et2O (9)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 4:1 (yield 44%); m.p.
1
191–193 °C. H NMR (CDCl3, 293 K): l 1.1 (t, 6H,
Hether), 3.5 (q, 4H, Hether), 7.2–7.5 (m br, Harom), 7.6
(br, 4H, CHbipy), 7.9 (br, 2H, CHbipy), 8.56 (br, 2H,
CHbipy). 31P{1H} NMR (CDCl3, 293 K): l −2.3 br.
31P{1H} NMR (CDCl3, 218 K): l 32.6br, 2.2s, −0.1s,
−2.3s. IR (Nujol mull, cm−1): 3185w, 3160w, 3100w,
3060w, 3050w (CꢀHarom), 2057s (N3), 1592w, 1559w
(C···C, C···N), 520s, 503m, 498m (PPh), 435w, 413w,
293w, 227w (lazole, CuꢀN). Elemental analysis: Anal.
Found: C, 64.01; H, 5.43; N, 11.83. Calc. for
C32H33N5OPCu: C, 64.26; H, 5.56; N, 11.71%. \m
10−3 mol l−1): 1.7 V−1 mol2 cm−1
.
2.2.7. [Cu2(N3)2(PPh3)3(bnim)] (6)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 1:1 (yield 44%); m.p.
1
122–124 °C. H NMR (CDCl3, 293 K): l 5.25 (s br,
2H, CH2), 7.1 (s br, 2H, H4+H5), 7.2–7.5 (m br,
45H, Harom), 7.6s br, 7.7 (s br, 1H, H2). 31P{1H} NMR
(CDCl3, 293 K): l −1.0 (br). 31P{1H} NMR (CDCl3,
218 K): l −0.5br, −3.7br. IR (Nujol mull, cm−1):
3100w, 3050w (CꢀHarom), 2024m (N3), 1585w, 1560w,
1509w (C···C, C···N), 526m, 514sh, 507s, (PPh), 465w,
442w, 285w, 273w, 259w, 249w (lazole, CuꢀN). Elemen-
tal analysis: Anal. Found: C, 66.26; H, 5.01; N, 9.51.
Calc. for C58H55N8P3Cu2: C, 66.49; H, 4.79; N, 9.69%.
(acetone,
V
conc.=1.0×10−3
.
mol l−1):
24.2
−1 mol2 cm−1
2.2.11. [Cu(N3)(PPh3)(Himt)] (10)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 2:1 (yield 40%); m.p.
1
184–186 °C. H NMR (CDCl3, 293 K): l 7.0 (br, 2H,
\
(acetone, conc.=1.1×10−3 mol l−1): 11.11
HHimt), 7.2–7.5 (m br, 15 Harom), 7.8 (br, 1H, NHHimt),
12.1 (br, 1H, NHHimt). 31P{1H} NMR (DMSO-d6, 293
K): l 43.1 [20], 36.0 [1], 26.4 [30], −3.8 [100], −6.8 [4].
IR (Nujol mull, cm−1): 3185w, 3150w, 3050w
(CꢀHarom), 2056s (N3), 1654w, 1583w, 1520m
(C···C, C···N), 521s, 505s, 497s (PPh), 442w, 337w,
270w, 231w (lazole, CuꢀN). Elemental analysis: Anal.
Found: C, 54.02; H, 4.34; N, 14.84; S, 6.59. Calc. for
C21H19N5PSCu: C, 53.90; H, 4.09; N, 14.96; S, 6.85%.
Vm−1 mol2 cm−1
.
2.2.8. [Cu(N3)(PPh3)(phen)] (7)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 1:1 (yield 63%); m.p.
1
189–190 °C. H NMR (CDCl3, 293 K): l 7.2–7.5 (m
br, 15H, Harom) 7.7 (br, 2H, Hphen), 7.8 (br, 2H, Hphen).
8.3 (br, 8H, Hphen), 8.9 (br, 2H, Hphen). 31P{1H} NMR

2758
C. Pettinari / Polyhedron 20 (2001) 2755–2763
\
(DMSO, conc.=1.0×10−4 mol l−1): 3.3
2.2.16. [Ag(N3)(PPh3)2]
Recrystallized from tetrahydrofurane–chloroform–
Vm−1 mol2 cm−1
.
1
diethyl ether (yield 88%); m.p. 238–242 °C. H NMR
(CDCl3, 293 K): l 7.2–7.5 (m br, 30H, Harom). 31P{1H}
NMR (CDCl3, 293 K): l 10.5s. 31P{1H} NMR (CDCl3,
218 K): l 32.1s [5], 23.7s [1], 15.8dd [2] (1J(109Ag–
2.2.12. [Cu(mimt)(PPh3)] (11)
This compound has been obtained in refluxing etha-
nol by using a ligand-to-metal molar ratio of 2:1 (yield
54%). Washed with diethyl ether; m.p. 166–169 °C. H
1
31P)=713 Hz, J(107Ag–31P)=620 Hz), 8.05d br [200]
1
(1J(Ag–31P)=413 Hz). IR (Nujol mull, cm−1): 3050w
(CꢀHazole+CꢀHarom), 2052s, 2029m, 2002w (N3),
1654w, 1584w, 1570w, (C···C, C···N), 517m, 503s,
NMR (CDCl3, 293 K): l 3.5 (br, 3H, NCH3), 6.7 (br,
2H, CHmimt), 7.2–7.5 (m br, 15H, Harom). 31P{1H}
NMR (CDCl3, 293 K): l 29.7s [1], −3.4 br [30].
31P{1H} NMR (CDCl3, 218 K): l 32.7br [4], −2.8s [1].
−4.7s [2], −5.2s [1]. IR (Nujol mull, cm−1): 3185w,
3110w (CꢀHarom), 1584w, 1570m (C···C, C···N), 520sh,
518s, 508s, 489s (PPh), 449w, 435w, 419m, 279w, 246w
(lazole, CuꢀN). Elemental analysis: Anal. Found: C,
59.99; H, 4.72; N, 6.7; S, 7.02. Calc. for C22H20N2PSCu:
C, 60.19; H, 4.59; N, 6.38; S, 7.30%. \m (acetone,
495m, 486m (PPh) 444w, 280w, 255w, 239w (lphosphine
AgꢀN). Elemental analysis: Anal. Found: C, 64.01; H,
4.59; N, 6.07. Calc. for C36H30N3P2Ag: C, 64.11; H,
,
4.48; N, 6.23%.
\
(CH2Cl2, conc.=1.0×10−3
m
mol l−1): 0.6 V−1 mol2 cm−1
.
2.2.17. [Ag(N3)(PPh3)(phen)] (15)
conc.=1.0×10−3 mol l−1): 7.2 V−1 mol2 cm−1
.
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 4:1 (yield 94%); m.p.
1
205–207 °C. H NMR (CDCl3, 293 K): l 7.2–7.5 (m
2.2.13. [Cu(bimt)] (12)
br, 15H, Harom) 7.7 (br, 2H, Hphen), 7.84 (d, 2H, Hphen),
8.30 (s, 2H, Hphen), 9.2 (br, 2H, Hphen). 31P{1H} NMR
(CDCl3, 293 K): l 29.5s [1], 12.6s [80]. 31P{1H} NMR
(CDCl3, 218 K): l 36.4s [1], 32.1s [5], 23.7s [2], 11.3dd
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 2:1 (yield 40%); m.p.
(dec.) \350 °C. H NMR (CDCl3, 293 K): 7.3 (br,
1
4H, CHarom). IR (Nujol mull, cm−1): 3050w (CꢀHarom),
1550w (C···C, C···N), 429w, 387w, 379w, 353w, 327w,
316w, 303w, 280w (lazole, CuꢀS, CuꢀN). Elemental
analysis: Anal. Found: C, 36.23; H, 1.81; N, 6.01; S,
27.81. Calc. for C7H4NS2Cu: C, 36.59; H, 1.75; N, 6.10;
S, 27.90%. \m (DMSO, conc.=1.0×10−3 mol l−1):
(1J(109Ag–31P)=669 Hz, J(107Ag–31P)=583 Hz). IR
1
(Nujol mull, cm−1): 3140w, 3110w, 3040w (CꢀHarom),
2016s (N3), 1616w, 1569w, 1507w (C···C, C···N), 520s,
504s (PPh), 484m, 471m, 443w, 419w (lphen, CuꢀN).
Elemental analysis: Anal. Found: C, 60.62; H, 3.84; N,
12.00. Calc. for C30H23N5PAg: C, 60.83; H, 3.90; N,
11.82%. \m (acetone, conc.=1.0×10−3 mol l−1): 2.3
1.8 V−1 mol2 cm−1
.
V
−1 mol2 cm−1
.
2.2.14. [Cu(pyt)] (13)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 2:1 (yield 35%); m.p.
(dec.) 191 °C. H NMR (CDCl3, 293 K): 7.4 (br, 4H,
2.2.18. [Ag(N3)(PPh3)(cupr)] (16)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 4:1 (yield 99%); m.p.
1
CHarom). IR (Nujol mull, cm−1): 3050w (CꢀHarom),
1617w, 1575w, 1547w (C···C, C···N), 508m 449m, 41m,
344w, 305m, 280w (lazole, CuꢀS, CuꢀN). Elemental
analysis: Anal. Found: C, 34.32; H, 2.34; N, 7.92; S,
17.98. Calc. for C5H4NSCu: C, 34.57; H, 2.32; N, 8.06;
S, 18.46%. \m (acetone, conc.=1.0×10−4 mol l−1):
1
232–234 °C. H NMR (CDCl3, 293 K): l 2.87 (s, 6H,
CH3), 7.3–7.5 (m br, Harom), 7.55 (d, 2H, CHcupr), 7.77
(s, 2H, CHcupr), 8.21 (d, 2H, CHcupr). 31P{1H} NMR
(CDCl3, 293 K): l 10.7br. 31P{1H} NMR (CDCl3, 218
K): l 36.1s [1], 32.0s [10], 23.7s [8], 10.1d br [60]
(1J(Ag–31P)=650 Hz,). IR (Nujol mull, cm−1): 3045w
(CꢀHarom), 2013s (N3), 1599w, 1559w, 1500w
(C···C, C···N), 545m, 523s, 500s, 494s (PPh), 435m,
422sh, 340br, 318w, 275w (lcupr, CuꢀN). Elemental
analysis: Anal. Found: C, 61.77; H, 4.57; N, 10.98.
Calc. for C32H27N5PAg: C, 61.95; H, 4.39; N, 11.29%.
0.3 V−1 mol2 cm−1
.
2.2.15. [Cu(N3)(Hmimt)3] (14)
This compound has been obtained as 1 by using a
ligand-to-metal molar ratio of 5:1 (yield 63%); m.p.
1
128–130 °C. H NMR (CDCl3, 293 K): l 3.6 (br, 9H,
\
(CH2Cl2, conc.=1.0×10−3 mol l−1): 6.6
NCH3), 6.7 (d, 6H, CHmimt). IR (Nujol mull, cm−1):
3060w (CꢀHarom), 2034m (N3), 1570w (C···C, C···N),
522s, 510s, 490s (PPh), 439w, 419w (lazole, CuꢀN,
CuꢀS). Elemental analysis: Anal. Found: C, 32.41; H,
4.03; N, 27.92; S, 20.99. Calc. for C12H18N8S3Cu: C,
32.17; H, 4.05; N, 28.13; S, 21.47%. \m (CH2Cl2,
conc.=1.0×10−3 mol l−1): 0.9 V−1 mol2 cm−1. MW
(CHCl3, 0.40×10−3 mol l−1): 299.
Vm−1 mol2 cm−1
.
2.2.19. [Cu(N3){P(o-tolyl)3}(cupr)] (17)
Tri-o-tolylphosphine P(o-tolyl)3 (0.608 g, 2.0 mmol)
was added to a diethyl ether suspension (100 ml) of
compound 8 (0.58 g, 1.0 mmol). After 24 h stirring, the
solid was filtered and washed with diethyl ether afford-
ing product 17 (0.309 g, 0.5 mmol) (yield 50%); m.p.

C. Pettinari / Polyhedron 20 (2001) 2755–2763
2759
1
230–232 °C. H NMR (CDCl3, 293 K): l 2.37 (s, 9H,
1556w, 1511m, 1500m (C···C, C···N), 550m, 491m,
452w, 433w, 398w, 313w (lcupr, CuꢀN). Elemental anal-
ysis: Anal. Found: C, 41.78; H, 2.90; N, 15.80; S, 14.26.
Calc. for C15H12N5S2Ag: C, 41.49; H, 2.79; N, 16.13; S,
14.76%. \m (CH2Cl2, conc.=0.5×10−3 mol l−1): 0.1
CH3P(o-tolyl)3), 2.78 (s, 6H, CH3cupr), 6.7 (d, 2H, Harom),
7.05 (t, 2H, Harom), 7.2–7.4 (m br, 8H, Harom), 7.48 (d,
2H, CHcupr), 7.74 (s, 2H, CHcupr), 8.17 (d, 2H, CHcupr).
IR (Nujol mull, cm−1): 3045w (CꢀHarom), 2025s (N3),
1616w, 1584w, 1558w, 1505m (C···C, C···N), 546m,
526s, 517m, 502s, 498sh (PPh), 457m, 436m, 422sh,
320br, 274w (lcupr, CuꢀN). Elemental analysis: Anal.
Found: C, 68.15; H, 5.47; N, 11.23. Calc. for
C35H33N5PCu: C, 68.0; H, 5.38; N, 11.33%. \m
V
−1 mol2 cm−1. From the filtered solution the complex
[Ag(SCN)(PPh3)2] was recovered.
2.2.23. [Ag(N3)(PPh3)(cyCN)(cupr)] (21)
cyCN (0.56 g, 5 mmol) was added to a diethyl ether
solution of compound 16 (0.52 g, 1.0 mmol). A clear
solution has been obtained immediately. After 4 h
stirring a microcrystalline precipitate formed, which has
been filtered off, washed with diethyl ether and shown
to be compound 21 (0.255 g, 0.35 mmol, 35%); m.p.
(CH2Cl2,
conc.=1.0×10−3
mol l−1):
0.2
V
−1 mol2 cm−1
.
2.2.20. [Cu2(N3)2(dppp)3] (18)
1,2-Bis(diphenylphosphino)propane (0.41 g, 1.0
mmol) was added to a diethyl ether–dichloromethane
1:1 solution (50 ml) of compound 8 (0.58 g, 1.0 mmol).
After 2 h stirring the solid was filtered and washed with
diethyl ether to afford compound 18 (0.295 g, 0.2
mmol, 60%); m.p.: dec., 113 °C; char. 218 °C. 1H
NMR (CDCl3, 293 K): l 2.6 (br, 4H, CH2dppp), 2.8 (br,
2H, CH2dppp) 7.0–8.0 (m br, 20H, Harom). IR (Nujol
mull, cm−1): 3060w (CꢀHarom), 2011m (N3), 1587w,
1556w, 1482sh (C···C, C···N), 548s, 511s (PPh) 450sh
br, 332w, 308w. Elemental analysis: Anal. Found: C,
67.00; H, 5.67; N, 5.45. Calc. for C81H78N6P6Cu2: C,
67.17; H, 5.43; N, 5.80%. \m (CH2Cl2, conc.=1.0×
1
212–215 °C. H NMR (CDCl3, 293 K): l 1.4, 1.7, 1.9
(m br, 11H, HcyCN), 2.85 (s, 6H, CH3cupr), 7.2–7.5 (m,
15H, CHarom), 7.52 (d, 2H, CHcupr), 7.73 (s, 2H,
CHcupr), 8.18 (s, 2H, CHcupr). IR (Nujol mull, cm−1):
3060w, 3045 (CꢀHarom), 2190m (CN), 2011s, 1967sh
(N3) 1619w, 1595m, 1558m, 1500m (C···C, C···N),
546m, 522s, 501sh, 494s (PPh), 435m, 422m, 398w,
315w, 300w, 281w, 265w, 251w, 226w (lcupr, CuꢀN).
Elemental analysis: Anal. Found: C, 63.91; H, 4.93; N,
11.26. Calc. for C39H38N6PAg: C, 64.20; H, 5.25; N,
11.52%. \m (CH2Cl2, conc.=0.4×10−3 mol l−1): 0.05
V
−1 mol2 cm−1
.
10−3 mol l−1): 0.1 V−1 mol2 cm−1
.
2.2.21. [Cu(tz)(PPh3)(phen)] (19)
3. Results and discussion
PPh3 (0.52 g, 2 mmol) and CS2 (4 mmol) were added
to a benzene solution (50 ml) of compound 7 (0.55 g,
1.0 mmol). After 2 h stirring the solution was concen-
trated to 20 ml. A red–orange precipitate formed
(0.500 g, 0.8 mmol, 80% yield) which has been filtered
3.1. Syntheses
By the interaction of [Cu(N3)(PPh3)2]2 with
monodentate nitrogen donors L (L=im, 1-meim, 2-
meim, 4-meim and bzim) in diethyl ether the complexes
[Cu(N3)(PPh3)2(L)] (1–5) (Scheme 1) have been imme-
diately obtained upon breaking of the bridging cop-
per(I)–azide bond in the dimeric starting reagent. On
the contrary, the donor bnim reacts slowly with
[Cu(N3)(PPh3)2]2, displacing only one molecule of PPh3
from the dimer and yielding the likely dinuclear com-
plex [Cu2(N3)2(PPh3)3(bnim)] (6) (Scheme 1).
The chelating bidentate ligands bipy, phen and cupr
reacts immediately with [Cu(N3)(PPh3)2]2 yielding the
mononuclear complexes [Cu(N3)(PPh3)(L2)] 7–9 upon
breaking of the bridging Cuꢀ(N3)ꢀCu bonds and dis-
placement of one PPh3 molecule from the Cu(I) coordi-
nation sphere (Scheme 1). The 1:1 adduct
[Cu(N3)(PPh3)(Himt)] (10) was obtained when Himt
reacts with [Cu(N3)(PPh3)2] in 1:1 ligand to metal molar
ratio, whereas when Hmimt reacts with [Cu(N3)(PPh3)2]
in ethanol, deprotonation of the sulfur ligand occurs
with the formation of the poorly soluble [Cu(mimt)-
(PPh3)] (11).
1
and washed with n-hexane (20 ml); m.p. 79–80 °C. H
NMR (CDCl3, 293 K): l 7.2–7.4 (m br, 15H, Harom),
7.4–8.0 (m 8H, CHphen). IR (Nujol mull, cm−1): 3065w
(CꢀHarom), 1965w, 1888w, 1817w, 1665w, 1582m,
1570sh (C···C, C···N), 541m, 513s, 498sh (PPh), 430m,
420m, 398w, 310w, 300w, 280w, 265w, 252w, 245w,
226w (lcupr, CuꢀN). Elemental analysis: Anal. Found:
C, 59.82; H, 3.83; N, 11.23; S, 10.56. Calc. for
C31H23N5PS2Cu: C, 59.65; H, 3.71; N, 11.22; S, 10.27%.
\
(CH2Cl2, conc.=0.8×10−3 mol l−1): 0.1
Vm−1 mol2 cm−1
.
2.2.22. [Ag(tz)(cupr)] (20)
CS2 (0.76 g, 10 mmol) was added to a diethyl ether
solution of compound 16 (0.52 g, 1.0 mmol). The
suspension was stirred overnight. The colorless precipi-
tate obtained was then filtered off, washed with diethyl
ether and shown to be compound 20 (0.141 g, 0.32
1
mmol, 32%); m.p. 171–172 °C. H NMR (CDCl3, 293
K): l 2.85 (s, 6H, CH3cupr), 7.4, 7.8, 8.2 (br, 6H,
CHcupr). IR (Nujol mull, cm−1): 1650w, 1620w, 1595w,

2760
C. Pettinari / Polyhedron 20 (2001) 2755–2763
The two S-donor acid ligands Hbtt and Hpyt react
the S-donors led instead to complex mixtures and were
not reproducible.
The chelating ligands phen and cupr reacts with
[Ag(N3)(PPh3)2]2 yielding the complexes [Ag(N3)-
(PPh3)(phen)] (15) and [Ag(N3)(PPh3)(cupr)] (16)
analogous to those of copper(I) (Scheme 2).
The reaction between 1 equiv. of compound 8 with 2
equiv. of P(o-tolyl)3 in diethyl ether results in the rapid
formation of the compound [Cu(N3){P(o-tolyl3)}(cupr)]
(17) upon displacement of the less basic PPh3. A differ-
ent pattern was found with the chelating diphosphine
dppp which easily displaced both cupr and PPh3 from
the copper complex 8 affording derivative having a
2:2:3 stoichiometry: [Cu2(N3)2(dppp)3] (18). The reac-
similarly through elimination of HN3 and lead to the
formation of the insoluble likely polynuclear copper(I)
complexes [Cu(bimt)]n (12) and [Cu(pyt)]n (13).
Unexpectedly, the reaction of [Cu(N3)(PPh3)2]2 with
an excess of Hmimt in diethyl ether proceeds in a
different way, to give a white solid formulated as
[Cu(N3)(Hmimt)3] (14) the two PPh3 molecules being
easily displaced by three Hmimt ligands.
Attempts to obtain imidazole derivatives of sil-
ver(I)phosphino azide by using the appropriate stoi-
chiometric amount or a strong excess of the N-donor
ligand were unsuccessful, the starting reagents being
always recovered. The reaction of [Ag(N3)(PPh3)2]2 with
Scheme 1.

C. Pettinari / Polyhedron 20 (2001) 2755–2763
2761
Scheme 2.
All the compounds are insoluble in diethyl ether and
ethanol, and, with the exception of 11–13, insoluble in
all common organic solvents, they are soluble in ace-
tone, DMSO, chlorinated solvents and acetonitrile. The
conductivity measurements, carried out only on the
stable solutions, show that our compounds are non-elec-
trolytes not only in dichloromethane, but also in more
ionizing solvents such as acetone, in agreement with
their non-ionic structure proposed in Schemes 1 and 2.
The ratio between the vaporimetric molecular weight
(CHCl3 solution) and the formula weight for com-
pounds 2 and 14 is 0.40 and 0.68, respectively, in
accordance with a partial dissociation of this kind of
complexes in chloroform solution.
tion of 4 with CS2 in benzene and in presence of excess
of PPh3 yields immediately the well-known [Cu(SCN)-
(PPh3)2] [12], whereas under the same conditions CS2
reacts with [Cu(N3)(PPh3)(phen)] yielding the thiotriazo-
late complex [Cu(tz)(PPh3)(phen)] (19). The reaction of
the silver complex [Ag(N3)(PPh3)(cupr)] (16) with CS2 in
benzene in presence of PPh3 proceeds instantaneously
resulting in the complete displacement of cupr and in
the condensation of CS2 with N3 to yield [Ag(SCN)-
(PPh3)2] [15]. The same reaction carried out in diethyl
ether without excess of phosphine proceeds slowly yield-
ing equimolar quantity of the thiotriazolate complex
[Ag(tz)(cupr)] (20) and of [Ag(SCN)(PPh3)2]. Finally the
reaction of [Ag(N3)(PPh3)(cupr)] (16) with cyCN pro-
duces the mixed-ligand complex [Ag(N3)(PPh3)(cyCN)-
(cupr)] (21), but not condensation products as the
tetrazole obtained by Beck and Felhammer [16].
All attempts to crystallize complexes 1–21 failed due
to their instability towards dissociation in organic
solvents.

2762
C. Pettinari / Polyhedron 20 (2001) 2755–2763
3.2. Spectroscopy
counter-ion. It was not possible to assign the w(CuꢀP)
vibrations, because they are likely hidden under some
absorptions characteristic of the azole ring system.
The IR spectra of 19 and 20 show the disappearance
of the asymmetric azide stretching bands and the ap-
pearance of the characteristic IR bands of the five-
membered heterocyclic anion that has formed by the
1,3-dipolar cycloaddition of the azido moiety to the
dipolarophile CS2. A strong band at approximately
1200 cm−1 appears which can be assigned to the thio-
carbonyl group [22]. The photolytical conversion of the
bonded azide in 7 to the bonded thiocyanate in
[Cu(SCN)(PPh3)2] can be followed by the disappearance
of the NꢀN stretching band and the appearance of a
strong band at approximately 2090 cm−1 typical of a
thiocyanate group [13].
3.2.1. IR spectra
The IR spectra of the silver and copper complexes
show several bands which may be taken as diagnostic
for the presence of azole and pyridine-type ligands: a
ring breathing band between 1600 and 1500 cm−1 and
the w(CH) stretching vibrations due to heterocyclic ring
above 3000 cm−1 can often be detected. In the spectra
of compounds 1–5, 10 and 14 the presence of NH
stretching vibrations between 3100 and 2400 cm−1
,
with no significant shift from the free ligand values, is
consistent with a monodentate neutral azole, coordi-
nated through the pyridine nitrogen (compounds 1–5)
or the thione sulphur (10 and 14).
Changes to the Hmimt and Himt spectra upon coor-
dination in 10 and 14 involve a slight perturbation to
the thioamide II band (1275 cm−1) and major pertur-
bation to thioamide IV (770, 740 cm−1) which is con-
verted from its clearly resolved component in the
3.2.2. NMR spectra
In the 1H NMR spectra of 1–10 and 15–17 the
signals due to azole or chelating ligands are always
deshielded with respect to the free donors: the higher
the Z (Z=ladduct−lN-donor), the higher is the donation
from the donor to the metal, and the stronger the
corresponding M–N interaction. The Z values further
confirm the existence, at least partial, of complexation
in solution. On the basis of the molecular weight deter-
minations mentioned above we hypothesize that the
complexes dissociated partly in solution. The reso-
nances observed are averaged between those of the
complex and the free ligand owing to a rapid exchange
reaction between both. This has been confirmed from
the spectra of compounds 1 and 7 recorded in presence
of N-donor ligand excess. No additional signal ap-
peared, but only a greater Z has been found.
uncoordinated molecule [17] into a peak (733 cm−1
)
with associated shoulders (720–746 cm−1) in the com-
plexes. Slight shift (920 cm−1) together with band
splitting also occurs with l(CꢀS) (675 cm−1) and
y(CꢀS) (520 cm−1). All these significant perturbations
(changes) in the thione region indicate sulfur donation
by the ligand [18]. Weak bands at approximately 300
cm−1, not present in the spectra of the free donors and
of the starting Cu(azide) complexes, are tentatively
assigned to CuꢀS stretching bands. This fact further
supports the coordination of the thione ligands through
the S atoms.
In the spectra of 1–18 the IR-active NꢀN asymmetric
stretch of the N3 ligand is in the range 2060–2020
cm−1. The position of this band cannot be used gener-
ally to infer bridging or non-bridging coordination
mode to the azide group [19]. However, due to the fact
that the NꢀN asymmetric stretching frequency differs
by about 30 cm−1 from that of the starting
[M(N3)(Ph3P)2]2 species where the azide is symmetric,
and that the NꢀN asymmetric stretch for terminal
azides generally falls at 2030 cm−1, structures contain-
ing monocoordinate terminal azide ligands, as those in
the Schemes 1 and 2, are likely for our compounds.
The band due to the cyCN ligand in complex 21
appears at 2190 cm−1. This CꢀN stretching frequency
is in the expected range being the isocyanide coordinate
to a metal center [20].
In the far-IR region of derivatives 1–11, 15–19 and
21 we always found a strong broad multiplet absorp-
tion near 500 cm−1, assignable to Whiffen’s y-vibra-
tions [21]. A second group of medium intensity
generally appeared near 410–420 cm−1, whereas the u-
and x-vibrations appeared as bands of weak intensity
between 270 and 250 cm−1. These bands are not very
sensitive to the nature of the azole donor and of the
The solution 31P NMR spectrum for each
triphenylphosphine complex at r.t. consists of a broad
singlet, presumed to be consequent on the presence of
rapid exchange equilibria. A unique absorption is gen-
erally detected at lower fields than that of the free
phosphine. The chemical shit values move upfield to-
wards the values of the free PPh3 with increasing coor-
dination number, the Z=ladduct−lfree phosphine being
generally greater for the complexes containing one P-
donor molecule and for silver with respect to copper(I)
derivatives.
Lability of the phosphorus ligands was evident in the
temperature dependence of the 31P NMR spectra of
some derivatives: the cooled (218 K) CDCl3 solutions
of derivatives [Cu(N3)(PPh3)2]2, 1, 5, 6, 7–10 show two
or more different signals, one of them generally due to
the free PPh3.
The spectra at 223 K of [Ag(N3)(PPh3)2]2, 15 and 16
show splitting for the signal at approximately 10 ppm
1
1
due to J(Ag–31P) coupling. The J(107,109Ag–31P) cou-
pling constant values observed are in the range typical
for the monophosphino complexes [23]. They provide a

C. Pettinari / Polyhedron 20 (2001) 2755–2763
2763
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with a coordination number of two whereas the 1J(Ag–
31P) coupling constant found for the signal at approxi-
mately 8 ppm in the spectrum of [Ag(N3)(PPh3)2]2 is
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4. Conclusions
A series of copper(I) and silver(I)–tertiary phosphine
adducts containing coordinated azide and heterocyclic
N-donor or S-donor ligands has been prepared and
characterized. A different pattern of reactivity has been
found for [Cu(N3)(PPh3)2]2 with respect to
[Ag(N3)(PPh3)2]2. Monodentate N- and S-donors are
able to displace phosphine ligands from the copper
center, but not from silver. The reactivity of the azide
group bonded to copper is also different from that of
the azide bonded to silver. In the first case condensa-
tion of CS2 with N3 is generally fast and yield a
tetrathioazolate derivative, in the second case the reac-
tion of CS2 with N3 is slow and the main product is a
thiocyanate derivative. From the reaction of
[Cu(N3)(PPh3)2]2 with N-donors mixed-ligand com-
plexes having coordination number four were always
obtained. With S-donor displacement of the azide
group was observed when the reaction was carried out
in polar solvents such as EtOH. None of the complexes
synthesized are very stable in solution, undergoing ex-
tensive ligand dissociation and rapid ligand exchange
even at low temperature and in non-polar solvents.
Azido groups bound to metal can be used to obtain
tetrathioazole complexes.
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