Copper(I) and mercury(II) halide complexes of 1,2-bis(diphenylthioylphosphino)hydrazine

Article abstract of DOI:10.1016/j.poly.2007.08.009

The reaction of 1,2-bis(diphenylthioylphosphino)hydrazine (L) with copper(I) and mercury(II) halides affords the complexes, [{CuLX}₂] (X = I, Br or Cl), [HgLX₂] (X = Cl or Br) and the tetrametallic complex, [{L(HgI₂)₂}₂]. Single crystal X-ray structures have been performed on the uncoordinated ligand, L, as well as the complexes [{CuLX}₂] (X = I, Br and Cl), [HgLBr₂] and [{L(HgI₂)₂}₂. The molecules of L exist as dimers as a result of pairs of N-H?S hydrogen bonds. The copper(I) complexes are centrosymmetric dimetallic species, the two copper atoms being bridged by L and the X atoms. In all cases the coordination sphere around the Cu atoms is approximately trigonal pyramidal with an 'S₂X₂' donor set. The complex, [HgLBr₂], is a distorted tetrahedral monomer with an 'S₂Br₂' donor set and L acting as a bidentate thus forming a seven-membered chelate ring. The tetramercury iodo complex, [{L(HgI₂)₂}₂], contains two 'L(HgI₂)₂' units linked centrosymmetrically via an I atom from each moiety. The geometry around the Hg atoms is distorted tetrahedral. The influence of hydrogen bonding between the hydrazine backbone hydrogens of L and the coordinated halide ions in for the structures of the metal complexes is discussed.

Full text of DOI:10.1016/j.poly.2007.08.009

Available online at www.sciencedirect.com
Polyhedron 26 (2007) 5398–5405
www.elsevier.com/locate/poly
Copper(I) and mercury(II) halide complexes
of 1,2-bis(diphenylthioylphosphino)hydrazine
*
*
Eric W. Ainscough , Andrew M. Brodie , Andreas Derwahl,
Graham H. Freeman, Carl A. Otter
Chemistry – Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand
Received 16 May 2007; accepted 6 August 2007
Available online 17 September 2007
Abstract
The reaction of 1,2-bis(diphenylthioylphosphino)hydrazine (L) with copper(I) and mercury(II) halides affords the complexes,
[{CuLX}2] (X = I, Br or Cl), [HgLX2] (X = Cl or Br) and the tetrametallic complex, [{L(HgI2)2}2]. Single crystal X-ray structures have
been performed on the uncoordinated ligand, L, as well as the complexes [{CuLX}2] (X = I, Br and Cl), [HgLBr2] and [{L(HgI2)2}2. The
molecules of L exist as dimers as a result of pairs of N–HÁ Á ÁS hydrogen bonds. The copper(I) complexes are centrosymmetric dimetallic
species, the two copper atoms being bridged by L and the X atoms. In all cases the coordination sphere around the Cu atoms is approx-
imately trigonal pyramidal with an ‘S2X2’ donor set. The complex, [HgLBr2], is a distorted tetrahedral monomer with an ‘S2Br2’ donor
set and L acting as a bidentate thus forming a seven-membered chelate ring. The tetramercury iodo complex, [{L(HgI2)2}2], contains two
‘L(HgI2)2’ units linked centrosymmetrically via an I atom from each moiety. The geometry around the Hg atoms is distorted tetrahedral.
The influence of hydrogen bonding between the hydrazine backbone hydrogens of L and the coordinated halide ions in for the structures
of the metal complexes is discussed.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Phosphine sulfide; Copper(I); Mercury(II); X-ray structures
1. Introduction
few reports exist on the hydrazine derivatives where the
backbone is (NH)2.
The coordination chemistry of phosphine chalcogenide
ligands is well established and their metal complexes have
been the subjects of various structure and reactivity studies
[1,2]. Of continuing interest are diphosphine chalcogenide
ligands of the general type Ph2P(E)(CH2)nP(E)Ph2 (E = O
or S) [3–13]. Also extensively studied are ligands of the type
Ph2P(E)NH(E)PPh2 (E = O or S) which, after deprotona-
tion, behave as monoanionic ligands, i.e., inorganic ana-
logues of acetylacetone (acac). However, comparatively
The compound Ph2P(NH)2PPh2 was reported by Niels-
den and Sisler, being prepared from the reaction between
Ph2PCl and anhydrous hydrazine [14]. Bock and Rudolph
prepared the chalcogen derivatives from analogous reac-
tions of Ph2P(E)Cl (E = O, S) [15]. The only coordination
compounds reported for these ligands are platinum and
palladium dichloride and molybdenum tetracarbonyl com-
plexes of Ph2P(S)(NH)2P(S)Ph2 (L), the title compound,
which were characterised by IR and 31P NMR [16,17].
Given the scarcity of information on the (1,2-diph-
enylphosphino)hydrazine derivatives and the absence of
any X-ray structural data, we have undertaken a study to
examine further the coordination chemistry of L. This
report comprises the first structural data for a (1,2-diph-
enylphosphino)hydrazine type ligand and five of its metal
*
Corresponding authors. Tel.: +64 6 3569099; fax: +64 6 3505682
(A.M. Brodie).
E-mail addresses: e.ainscough@massey.ac.nz (E.W. Ainscough), a.bro-
die@massey.ac.nz (A.M. Brodie).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.08.009

E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
5399
complexes with copper(I) and mercury(II) halides, includ-
ing an unusual tetrametallic complex, [{L(HgI2)2}2]. A
common feature for all the complexes is the occurrence
of hydrogen bonding between the hydrazine backbone
hydrogens of L and the coordinated halide ions.
microcrystalline precipitate formed on cooling. Yield
0.097 g. An analytically pure sample and X-ray quality crys-
tals of [CuLBr]2 Æ 2MeCN were obtained after a second
recrystallisation of a portion of the material from hot
MeCN. Anal. Calc. for C48H44Br2Cu2N4P4S4: C, 47.41;
H, 3.65; N, 4.61. Found: C,47.64; H, 3.55; N, 5.19%. mPS
cmÀ1: 620, 601. mNH/cmÀ1: 3075. m.p. 255–270 ꢁC (dec.).
/
2. Experimental
2.1. Materials and instrumentation
2.2.4. [{CuLI}2] Æ CH3CN
A mixture of L (0.100 g, 0.215 mmol) and CuI (0.041 g,
0.215 mmol) in CHCl3 (5 mL) was heated at reflux over
1 h. The mixture was allowed to cool and a white precipi-
tate was collected by filtration. Yield 0.075 g. X-ray quality
crystals of [{CuLI}2] Æ 2MeCN and an analytically pure
crop of the monosolvated complex were obtained by
recrystallisation from hot MeCN (20 mL). Anal. Calc. for
C50H47Cu2I2N5P4S4: C, 44.45; H, 3.51; N, 5.18. Found:
All reactions were carried out under an atmosphere of
dry dinitrogen. Analytical grade solvents were purchased
from standard chemical suppliers and were used without
further purification. HgI2 (M&B), HgBr2 (BDH) and
HgCl2 (M&B) were used as received. CuCl, CuBr, CuI
and (1,2-diphenylphosphino)hydrazine were prepared
1
according to the literature [18,19,14]. H and 31P NMR
spectra were recorded on a Bruker Avance 400 spectrome-
ter. IR spectra were run as KBr discs on a Perkin–Elmer
FT-IR Paragon 1000 spectrometer. Microanalyses were
performed by the Campbell Microanalytical Laboratory,
University of Otago.
44.11; H, 3.24; N, 5.62%. mPS/cmÀ1: 613, 602. mNH/cmÀ1
3085. m.p. 255–261 ꢁC (dec.).
:
2.2.5. [{L(HgI2)2}2]
A mixture of L (0.100 g, 0.215 mmol) and HgI2 (0.196 g,
0.431 mmol) in MeCN (20 mL) was heated at reflux over
1.5 h. The reaction mixture was filtered while hot and a pale
yellow crystalline solid formed on cooling. Yield 0.217 g.
Anal. Calc. for C48H44Hg4I8N4P4S4: C, 20.99; H, 1.61; N,
2.04. Found: C, 21.06; H, 1.60; N, 2.09%. mPS/cmÀ1: 620,
595. mNH/cmÀ1: 3154, 3052. m.p. 168–200 ꢁC (dec.).
2.2. Syntheses
2.2.1. 1,2-Bis(diphenylthioylphosphino)hydrazine (L)
To a solution of 1,2-bis(diphenylphosphino)hydrazine
(2.585 g, 6.436 mmol) in toluene (20 mL) was added sulfur
(0.42 g, 13.1 mmol) and the mixture was heated at reflux
over 2 h. The toluene was removed on a rotary evaporator
to give a cream coloured solid that was washed with cold
acetone (2 · 5 mL). The solid was dissolved in hot acetone
(60 mL) and slow evaporation of the solution produced a
2.2.6. [HgLCl2]
A mixture of L (0.100 g, 0.215 mmol) and HgCl2
(0.059 g, 0.217 mmol) in MeCN (35 mL) was heated at
reflux over 5 h. The reaction mixture was allowed to cool
and a white precipitate was collected by filtration. Yield
0.123 g. A small amount of material was recrystallised from
hot nitromethane. Anal. Calc. for C24H22Cl2HgN2P2S2: C,
39.16; H, 3.01; N, 3.81. Found: C, 38.92; H, 3.04; N, 3.92%.
mPS/cmÀ1: 619, 594. mNH/cmÀ1: 3057. m.p. 215–230 ꢁC
(dec.).
1
crop of white crystalline material. Yield 1.15 g (38%). H
NMR (CDCl3): d 7.81–7.76 (m, 8H, PPh2), 7.46 (m, 4H,
PPh2), 7.34–7.30 (m, 8H, PPh2), 4.62 (m, 2H, NH). 31P
NMR (CDCl3): d 66.0 (s, 2P, P@S). mPS/cmÀ1: 633, 615.
m
NH/cmÀ1: 3222, 3158. Anal. Calc. for C24H22N2P2S2: C,
62.05; H, 4.99; N, 6.03. Found: C, 62.18; H, 4.73; N,
6.07%. m.p. 201–204 ꢁC (lit. 204 ꢁC).
2.2.7. [HgLBr2]
2.2.2. [{CuLCl}2]
A mixture of L (0.100 g, 0.215 mmol) and HgCl2
(0.078 g, 0.216 mmol) in MeCN (10 mL) was heated at
reflux over 2 h. The reaction mixture was allowed to cool
and a white precipitate was collected by filtration, washed
with cold acetonitrile and air dried. Yield 0.140 g. A sample
of the material was recrystallised from hot nitromethane
and crystals suitable for X-ray analysis were also obtained
from this solvent. Anal. Calc. for C24H22Br2HgN2P2S2: C,
34.94; H, 2.69; N, 3.40. Found: C, 34.88; H, 2.66; N,
3.41%. mPS/cmÀ1: 620, 593. mNH/cmÀ1: 3075. m.p. 210–
225 ꢁC (dec.).
A mixture of L (0.100 g, 0.215 mmol) and CuCl (0.022 g,
0.222 mmol) in MeCN (70 mL) was heated at reflux over
7 h. The reaction mixture was filtered while hot and a white
microcrystalline precipitate formed on cooling. Yield
0.105 g. An analytically pure sample and X-ray quality
crystals of [{CuLCl}2] Æ 4MeCN were obtained after a sec-
ond recrystallisation of a portion of the material from hot
MeCN. Anal. Calc. for C48H44Cl2Cu2N4P4S4: C, 51.15; H,
3.94; N, 4.97. Found: C, 51.10; H, 4.02; N, 5.01%. mPS/
cmÀ1: 620, 599. mNH/cmÀ1: 3070. m.p. 246–250 ꢁC (dec.).
2.2.3. [{CuLBr}2]
2.3. Crystallography
A mixture of L (0.100 g, 0.215 mmol) and CuBr (0.032 g,
0.222 mmol) in MeCN (90 mL) was heated at reflux over
4 h. The reaction mixture was filtered while hot and a white
The X-ray data were collected on a Siemens P4 four cir-
cle diffractometer, using a Siemens SMART 1K CCD area

5400
E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
detector. The crystals were mounted in an inert oil, trans-
ferred into the cold gas stream of the detector and irradi-
ated with graphite monochromated Mo-Ka (k = 0.71073 A)
Pure samples of copper halide complexes of stoichiome-
try [{CuLX}2] (X = I, Br or Cl) were obtained from the
reactions between the ligand and the appropriate copper(I)
halide followed by crystallisation from hot acetonitrile
solutions. Satisfactory elemental analyses were obtained
in each case. The complexes have poor solubility in com-
mon organic solvents at room temperature which pre-
cluded characterisation by NMR. In the IR spectra, both
the NH and PS stretching bands are shifted to lower wave
numbers when compared with the free ligand. Thus the
m(NH) stretching frequencies are observed at 3084, 3070
and 3074 cmÀ1 and the pairs of m(PS) bands at 612 and
601, 619 and 599 and 620 and 600, respectively, for the ser-
ies X = I, Cl, Br.
˚
X-rays. The data were collected by the SMART program
and processed with SAINT to apply Lorentz and polarisation
corrections to the diffraction spots (integrated 3 dimension-
ally). The structures were solved by direct methods and
refined using the SHELXTL [20] program. The hydrogen
atoms bound to the nitrogen atoms on the hydrazine back-
bone were located from the electron difference map and
refined using a riding model. All other hydrogen atoms
were calculated at ideal positions. Refinement, collection
and crystal data are given on Table 1.
3. Results and discussion
Similarly 1:1 mercury(II) chloride and bromide com-
plexes, [HgLX2] (X = Cl or Br) were obtained from the
reaction of equimolar ligand and mercury(II) halide in
MeCN. Initially we attempted to prepare a 1:1 mercury(II)
iodide complex in the same way but it was apparent that we
were obtaining mixtures, with one of the components being
the [{L(HgI2)2}2] species reported here. This latter complex
was obtained in good yield from the reaction of the metal
salt and the ligand in a 2:1 molar ration. The IR spectra
for the mercury bromide and chloride complexes are simi-
lar with NH stretching frequencies at 3074 and 3056 cmÀ1
and pairs of PS stretching frequencies at 618 and 593
and 619 and 593 cmÀ1. The tetrametallic mercury iodide
complex has a different spectrum with two stretching
3.1. Syntheses of the compounds
The free ligand L was prepared from the sulfuration of
the parent phosphine, (1,2-diphenylphosphino)hydrazine
in toluene. This differs from the previously reported method
where it was prepared from the reaction between Ph2P(S)Cl
and anhydrous hydrazine [15]. The 31P NMR chemical shift
of L is 66 ppm in CDCl3 and downfield of phosphorus sig-
nal in (1,2-diphenylphosphino)ethane (L1) which occurs at
44 ppm. The ligand exhibits IR bands at 3222 and
3158 cmÀ1, (assigned to NH) and 633 and 615 cmÀ1
(assigned to P@S) stretching frequencies, respectively.
,
Table 1
Crystal and refinement data
Compound
L
[{CuLI}2] Æ 2MeCN [{CuLBr}2] Æ MeCN
[{CuLCl]}2 Æ 4MeCN] [{L(HgI2)2}2]
[HgLBr2]
Molecular formula
Molecular weight
(M)
C
464.50
24H22N2P2S2 C52H50Cu2I2N6P4S4 C50H47Br2Cu2N5P4S4 C56H56Cl2Cu2N8P4S4 C48H44Hg4I8N3P4S4 C24H22Br2HgN2P2S2
1391.98
1256.95
1291.19
2746.56
1649.81
T (K)
200(2)
200(2)
200(2)
200(2)
83(2)
83(2)
Crystal system
Space group
a (A)
monoclinic
P2(1)
10.5252(2)
18.2405(3)
24.7358(1)
monoclinic
P2(1)/n
12.0932(2)
15.4958(2)
15.0715(3)
monoclinic
P2(1)/n
12.019(2)
15.559(3)
15.181(3)
triclinic
triclinic
monoclinic
P2(1)/n
8.0292(1)
17.4989(2)
18.9981(2)
ꢀ
ꢀ
P1
P1
˚
10.5608(1)
11.1659(1)
15.1527(1)
70.607(1)
72.411(1)
65.012(1)
1500.03(2)
2
1.088
1.429
54.20
6468
10.5535(3)
11/8678(3)
14.8929(4)
78.697(1)
74.292(1)
68.929(1)
1665.43(8)
2
13.154
2.738
51.36
6289
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
102.253(1)
94.648(1)
91.82(3)
92.535(1)
3
˚
V (A )
4640.72(12)
8
0.381
1.330
50.78
2815.02(8)
4
2.155
1.642
51.36
5329
2837.3(10)
4
2.455
1.471
53.26
5737
2666.66(5)
4
9.062
2.055
54.26
5862
Z
l (MoKa) (mmÀ1
)
qcalc (g cmÀ3
2h Maximum (ꢁ)
)
Number of unique 15697
reflections
Data/restraints/
parameters
15697/1/1081 5329/0/317
5737/0/317
6468/0/347
6289/0/325
5862/0/298
Final R indices
[I > 2r(I)]
R1 = 0.0279 R1 = 0.0198
R1 = 0.0434
R1 = 0.0259
R1 = 0.0224
R1 = 0.0235
wR2 = 0.0642 wR2 = 0.0496
R indices (all data) R1 = 0.0315 R1 = 0.0220
wR2 = 0.0667 wR2 = 0.0504
Goodness of fit on 1.098 1.112
F2
wR2 = 0.1275
R1 = 0.0575
wR2 = 0.1360
1.130
wR2 = 0.0730
R1 = 0.0304
wR2 = 0.0757
1.048
wR2 = 0.0523
R1 = 0.0238
wR2 = 0.0530
1.107
wR2 = 0.0506
R1 = 0.0306
wR2 = 0.0542
1.087

E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
5401
frequencies assignable to NH at 3153 and 3051 cmÀ1 and a
pair of PS stretching frequencies at 617 and 595 cmÀ1. The
solubilities of the mercury complexes in common organic
solvents were also low.
The two P@S stretching frequencies for L at 632 and
614 cmÀ1 are both lowered by about 12–21 cmÀ1 for the
complexes, consistent with metal coordination of the sulfur
atoms [16]. Similarly, the two N–H stretching frequencies
at 3222 and 3158 cmÀ1 for L are replaced with one band
at about 3056–3084 cmÀ1 for all the complexes, apart from
[{L(HgI2)2}2], which displays two bands at 3052 cmÀ1 and
3153 cmÀ1. The lowering of these frequencies is consistent
with the presence of N–HÁ Á ÁX hydrogen bonds in the struc-
ture, rather than coordination by N–H groups in a strained
four-membered ring. Moreover, the trend of the m(NH) fre-
quencies to lower energies increases along the series
IÀ < BrÀ < ClÀ, which parallels the hydrogen-bonding
ability of the anions [21].
All of the copper complexes with L remained unchanged
upon recrystallization from hot CH3CN. However, the
CuCl complex of 1,2-bis(diphenylphosphino)hydrazine,
after initial recrystallization from hot toluene and then left
to crystallize for several months, was hydrolytically unsta-
ble with cleavage of the P–N bonds [22], and one of the
products isolated was diphenylphosphinic acid. Similar
reactivity has been observed for aminobis(phosphines)
[23]. The polarity of the P–N bond favours attack on the
phosphorus atom by the water nucleophile, and this is
followed by oxidation of the P atom. This reaction is
slowed down when the ligand is already oxidized as in L
and does not occur when P–C bonds are present. This is
the first reported cleavage reaction for a coordinated
hydrazinobis(phosphine).
Fig. 1. Diagram of the dimeric form of L in the solid state. Thermal
ellipsoids drawn at 50% probability level and most hydrogen atoms
removed for clarity.
opposite sides of the PCCP mean plane [25]. Selected bond
lengths and angles are given in Table 2. Structural data on
hydrazinobis(phosphine) adducts is scarce although the P–
˚
N and N–N bond lengths in L (average 1.695 and 1.441 A)
are comparable with those observed in a cyclic example,
3,6-dimethoxy-1,2,4,5-tetraaza-3,6-diphosphacyclohexan-
˚
edisulfide (average 1.663 and 1.435 A) and the P–S bond
1
˚
lengths (average 1.945 A) are comparable to those in L
(1.941 A) [26].
˚
3.2.2. Copper(I) halide complexes of L
X-ray quality crystals of the copper(I) halide complexes
of L were obtained in from MeCN solutions. In each case
the overall structure is similar and comprises a dimetallic
species of stoichiometry [{CuLX}2] in which L acts as a
bridging ligand, bonding to separate copper centres
through either sulfur atom (Fig. 2., X = I). Selected bond
lengths and angles are given in Table 3.
3.2. Description of the structures
3.2.1. 1,2-Bis(diphenylthioylphosphino)hydrazine (L)
The free ligand L crystallises from an acetone solution in
the space group P2(1) with four molecules in the asymmet-
ric unit. Every independent molecule has a similar confor-
mation in which the PNNP backbone has a torsion angle of
around 16ꢁ and both pairs of N–H and P@S bonds are
directed towards the same side of the mean PNNP plane.
This arrangement of the sulfur atoms is similar to that
observed in the structure of Ph2P(S)CH2CH2P(S)Ph2 (L1)
although the PCCP backbone is slightly more twisted with
a torsion angle of ca. 25ꢁ [24]. However, molecules of L
exist as hydrogen bonded dimers in the solid state with
The coordination spheres of the Cu(I) centres have
‘S2X2’ donor sets with a somewhat unusual geometry,
being best described as trigonal pyramidal. The copper
bonds to X1, S1 and S2 (sulfur atoms from different
ligands) and X1A. The halides link the two symmetry
related Cu atoms with the Cu–X1A bond lengths being
˚
around 0.5–0.65 A longer than the Cu–X1 bonds lengths
(Table 3). The X1A ion forms the apex of the trigonal pyr-
amid. The sum of the three angles in the coordination
planes formed about the copper atom by X1 and the sulfur
atoms are approximately 354.7, 357.1 and 356.9ꢁ, respec-
tively, for X1 = I, Br and Cl hence approaching an ideal
trigonal geometry. The copper atom is displaced from the
trigonal plane towards X1A by 0.3210, 0.2318 and
both molecules in the dimer contributing one N–HÁ Á Á
S
bond to the array (Fig. 1), whereas the sulfur atoms in
L1 are only involved in close contacts with aromatic hydro-
gen atoms on nearby diphenylphosphine groups. In this
respect, the packing in L more resembles Ph2P(O)CH2CH2-
P(O)Ph2, in which two adjacent molecules each supply a
close contact between a hydrogen atom on the (CH2)2
backbone and a P@O bond, although in this compound
the P@O bonds on the same molecule are directed towards
˚
0.2360 A, respectively, for X = I, Br and Cl.
The overall structures are comparable to the arrange-
ment observed in [{CuL1Cl}2] [27] but with some subtle dif-

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E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) for L
Molecule A
Molecule B
Molecule C
Molecule D
P1–N1
P2–N2
N1–N2
1.693(2)
1.707(2)
1.446(3)
1.701(2)
1.6859(19)
1.435(3)
1.6968(19)
1.695(2)
1.439(3)
1.701(2)
1.683(2)
1.443(3)
P1–S1
P2–S2
1.9507(9)
1.9401(9)
116.77(7)
114.26(8)
113.68(9)
115.77(8)
113.15(10)
115.02(9)
111.55(14)
112.66(14)
1.9397(9)
1.9504(9)
116.39(8)
114.60(8)
112.90(9)
116.81(8)
112.76(9)
114.73(8)
110.70(14)
113.04(15)
1.9399(9)
1.9516(9)
117.05(7)
114.58(8)
113.37(9)
116.54(8)
112.28(9)
113.93(9)
113.05(14)
111.17(14)
1.9415(9)
1.9485(9)
115.76(8)
114.55(8)
113.07(9)
117.31(8)
112.57(9)
115.27(9)
110.59(14)
113.12(15)
S1–P1–N1
S1–P1–C11
S1–P1–C21
S2–P2–N2
S2–P2–C31
S2–P2–P2–C41
P1–N1–N2
P2–N2–N1
Fig. 2. Diagram of the dimetallic complex [{CuLI}2]. Thermal ellipsoids drawn at 50% probability level and most hydrogen atoms removed for clarity.
Table 3
˚
Selected bond lengths (A) and angles (ꢁ) for the copper(I) complexes
[{CuLI}2] Æ 2MeCN
[{CuLBr}2] Æ MeCN
[{CuLCl}2] Æ 4MeCN
Cu1–S1
Cu1–S2
Cu1–X1
Cu1–X1A
P1–S1
2.3045(5)
2.2951(5)
2.5990(3)
3.0859(3)
1.9769(6)
1.9859(6)
1.444(2)
2.888(12)
2.2927(12)
2.4353(8)
3.0851(1)
1.9865(14)
1.9884(15)
1.450(4)
2.2822(4)
2.2851(4)
2.3117(4)
2.8687(5)
1.9864(5)
1.9848(5)
1.4448(16)
P2–S2
N1–N2
S1–Cu1–S2
115.752(19)
118.448(15)
120.487(16)
94.951(15)
98.924(16)
99.130(9)
115.15(4)
119.41(4)
122.53(4)
95.76(4)
98.03(4)
93.36(3)
114.073(15)
120.657(15)
122.121(15)
99.79(1)
100.56(1)
87.86(1)
S1–Cu1–X1
S1–Cu1–X2
S1–Cu1–X1A
S2–Cu1–C1A
X1–Cu1–X1A
Cu1–X1–Cu1A
P1–S1–Cu1
P2–S2–Cu1
80.870(10)
106.44(2)
104.66(2)
86.64(3)
105.38(5)
102.79(5)
92.14(1)
101.705(8)
100.396(19)

E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
5403
ferences. In the three L Cu(I) complexes there are four
strong intramolecular hydrogen bonds (Table 4) of the type
N–HÁ Á ÁX which have the effect of creating two pairs of
fused 6-membered chelate rings. This assembly appears to
have an increasing influence on the PNNP backbone as
X becomes smaller and more electronegative (in each case
the torsion angle for PNNP is 10, 13 and 16ꢁ for X = I, Br
and Cl). In [{CuL1Cl}2] the PCCP torsion angle is 4ꢁ and
the intramolecular contacts from the ligand backbone are
long (the relevant C–HÁ Á ÁCl contacts are 2.708 and
ions through each sulfur donor with each ligand creating
a moiety of stoichiometry ‘L(HgI2)2’. Two such moieties
are linked by iodide bridges which lie about a centre of
inversion to give the tetrametallic complex (Fig. 3).
Selected bond lengths and angles are given in Table 5.
Hence the molecule contains two different tetrahedral
‘I3S’ coordination spheres. Hg1 is bonded to I1 and I2
˚
[2.6726(4) and 2.6919(3) A] and is bridged to Hg2 through
˚
a slightly longer bond to I3 [3.1084(3) A]. Hg2 is coordi-
nated by three bridging iodine ligands I3, I4 and I4A; the
˚
˚
2.581 A) compared with [{CuLCl}2] where N–HÁ Á ÁCl are
bond lengths being 2.7244(4), 2.7323(3) and 3.1572(4) A,
˚
˚
2.410 and 2.351 A. Hence the ligand backbones in the
respectively. The Hg2–S2 bond length of 2.5587(11) A is
[{CuLX}2] complexes remain twisted in their compression
towards the Cu2X2 core whereas in [{CuL1Cl}2] the ligand
backbone is somewhat flattened. In [{CuLCl}2]the sulfur
atoms on the same ligand are further apart (5.989 cf.
significantly shorter than the Hg1–S1 bond length of
2.6150(11) A although the P@S bond lengths are similar
and longer than in the free ligand [1.9965(16) and
˚
˚
˚
2.0012(16) A compared to an average of 1.945 A]. As with
the dimetallic copper(I) halide structures, the NH–NH
ligand backbones in [{L(HgI2)2}2] participate in strong
hydrogen bonding interactions with the iodide coligands;
˚
5.846 A) even though the phosphorus atoms are closer
˚
(4.083 cf. 4.424 A). The impact of this on the coordination
spheres is that in [{CuL1Cl}2] the CuÁ Á ÁCu separation in
˚
˚
˚
[{CuLCl}2] is longer (3.751 cf. 3.327 A) and the bridging
H1Á Á ÁI2 is 2.91 A and H2Á Á ÁI3 is 2.90 A and the PNNP tor-
˚
Cu–Cl distances (2.869 cf. 2.639 A) are also increased.
sion angle is 17.7ꢁ.
3.2.3. [{L(HgI2)2}2]
3.2.4. [HgLBr2]
The reaction of 2 equiv of HgI2 with L and subsequent
recrystallisation from acetonitrile afforded the unusual tet-
rametallic complex [{L(HgI2)2}2]. In this complex L is
again acting as a bridging, ligand binding different Hg(II)
From the reaction of 1 equiv of HgBr2 with L, crystals
of [HgLBr2] were obtained from nitromethane in which L
acts as a bidentate ligand bonding through the two sulfur
atoms to form a seven-membered chelate ring. The com-
plex has a distorted tetrahedral geometry and selected bond
lengths and angles are given in Table 6.
Table 4
The complex (Fig. 4) is comparable with [HgL1Br2] which
has a similar donor set and distorted tetrahedral coordina-
tion geometry [8]. The ligand bite angle of 119.52(3)ꢁ in
[HgLBr2] is close to that of 118.85(8)ꢁ in [HgL1Br2]. How-
ever the bond lengths in the coordination sphere of each
complex are quite different. The two Hg–S bonds in
˚
Hydrogen-bond lengths (A) and angles (ꢁ) in the [{CuLX}2] complexes
D–H
HÁ Á ÁA
DÁ Á ÁA
\(DHA)
N1–H1Á Á ÁI1
0.85
0.86
0.92
0.89
0.93
0.89
2.84
2.75
2.62
2.59
2.35
2.41
3.6506(15)
3.5480(14)
3.502(3)
3.436(3)
3.2394(12)
3.2674(12)
160.7
156.4
160.3
158.5
159.7
161.7
N2–H2Á Á ÁI1A
N2–H2Á Á ÁBr1
N1–H1Á Á ÁBr1
N1–H1Á Á ÁCl1
N2–H2Á Á ÁCl1
˚
[HgLBr2] are shorter at 2.5312(9) and 2.5173(9) A compared
1
˚
to 2.678(2) and 2.552(2) A in [HgL Br2] while the two Hg–Br
Fig. 3. Diagram of the tetrametallic complex [{L(HgI2)2}2]. Thermal ellipsoids drawn at 50% probability level and most hydrogen atoms removed for
clarity.

5404
E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
Table 5
cent molecules of [HgLBr2] to engage in intermolecular
hydrogen bonding in the crystalline state, with the dis-
˚
Selected bond lengths (A) and angles (ꢁ) for [{L(HgI2)2}2]
˚
Hg1–S1
Hg1–I1
Hg1–I2
Hg1–I3
P1–S1
2.6150(11)
2.6726(4)
2.6919(3)
3.1084(3)
1.9965(16)
1.441(5)
Hg2–S2
Hg2–I3
Hg2–I4
Hg2–I4A
P2–S2
2.5587(11)
2.7244(4)
2.7323(3)
3.1752(4)
2.0012(16)
tances H1Á Á ÁBr2A and H2Á Á ÁBr1A being 2.58 and 2.64 A,
respectively. It also results in a lengthening of the Hg–Br
bonds along with any compensating effects due to short
Hg–S bonds. The outcome is the formation of a second,
seven-membered chelate-type ring viz. Hg1A–Br1AÁ Á ÁH2–
N2–N1–H1Á Á ÁBr2A in a bridging arrangement as columns
of [LHgBr2] stack along the a-axis (Fig. 5). Further
N1–N2
S1–Hg1–I1
S1–Hg1–I2
I1–Hg1–I2
S1–Hg1–I3
I1–Hg1–I3
I2–Hg1–I3
Hg1–I3–Hg2
P1–S1–Hg1
105.26(3)
S2–Hg2–I3
S2–Hg2–I4
I3–Hg2–I4
S2–Hg2–I4A
I3–Hg2–I4A
I4–Hg2–I4A
Hg2–I4–Hg2A
P2–S2–Hg2
115.50(3)
114.88(3)
134.101(12)
97.27(3)
102.885(11)
93.488(10)
99.254(10)
100.80(5)
111.85(3)
128.543(12)
104.81(3)
96.727(10)
89.626(10)
90.374(10)
103.50(6)
Table 6
˚
Selected bond lengths (A) and angles (ꢁ) for [HgLBr2]
Hg1–S1
Hg1–Br1
P1–S1
2.5173(9)
2.6089(4)
1.9878(12)
1.419(4)
Hg1–S2
Hg1–Br2
P2–S2
2.5312(9)
2.6078(4)
1.9979(12)
N1–N2
S1–Hg1–S2
S1–Hg1–Br1
S1–Hg1–Br2
P1–S1–Hg1
119.52(3)
S2–Hg1–Br1
S2–Hg1–Br2
Br1–Hg1–Br2
P2–S2–Hg2
112.55(2)
102.19(2)
111.107(12)
108.36(4)
98.82(2)
112.98(2)
107.43(4)
˚
bonds are considerably longer at 2.6089(4) and 2.6078(4) A
˚
compared to 2.5592(11) and 2.5509(11) A.
A possible reason for this presents itself from an exam-
ination of the packing in [HgLBr2]. Contrary to the con-
formation found in the bridging structures previously
discussed, the N–H bonds on the ligand backbone of L
are now directed towards the opposite side of the PNNP
mean plane to the sulfur donor atoms. This allows adja-
Fig. 5. A diagram showing how [HgLBr2] molecules pack in columns
along the a-axis.
Fig. 4. Diagram of the complex [HgLBr2]. Thermal ellipsoids drawn at 50% probability level and most hydrogen atoms removed for clarity.

E.W. Ainscough et al. / Polyhedron 26 (2007) 5398–5405
5405
reinforcement of the columnar array is provided by the
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The ligand, 1,2-bis(diphenylthioylphosphino)hydrazine
(L), reacts with copper(I) and mercury(II) halides affording
the complexes, [{CuLX}2] (X = I, Br or Cl), [HgLX2] (X =
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much more dominant effect than is observed with similar
complexes of L1, and is an interesting ligand design
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Appendix A. Supplementary material
CCDC 646490–646494 contains the supplementary crys-
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conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: depos-
it@ccdc.cam.ac.uk. Supplementary data associated with
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