Copper(I) complexes with the triarylphosphanes PPhn(C 6H4CH2NMe2-2)3- n (n = 0-2) and PPh2[C6H4CH 2N(CH2CH2)2O-2]. Synthesis and structural characterization

Article abstract of DOI:10.1016/j.poly.2014.01.035

Several copper(I) complexes of type [CuXPPh_n(C₆H ₄CH₂NMe₂-2)_3-n] [X = Cl, n = 1 (2), 2 (3); X = I, n = 0 (4), 1 (5), 2 (6)] were prepared by reacting CuX with the appropriate triarylphosphane in a 1:1 molar ratio. The ionic species [Cu(MeCN)₂PPh₂{C₆H₄CH ₂N(CH₂CH₂)₂O-2}]⁺PF ₆^- (7) was obtained in the reaction between [Cu(MeCN) ₄]PF₆ and PPh₂{C₆H ₄CH₂N(CH₂CH₂)₂O-2} (1). All compounds were characterized by NMR spectroscopy (¹H and ³¹P) and mass spectrometry. For compound 7 the ¹⁹F NMR spectrum was also recorded. Single-crystal X-ray diffraction studies put in evidence a P,N monometallic biconnective coordination behavior of the ligand in compounds 3, 6·0.5CH₂Cl₂ and 7·CH ₂Cl₂, while in compound 4 a P,N,N monometallic triconnective behavior was observed. In species 2 the unit cell contains two independent molecules; in one of them the PN₂ ligand behaves P,N,N-monometallic triconnective, while in the other as a P,N-monometallic biconnective moiety. The N→Cu intramolecular coordination induces planar chirality to the metal center and, as a consequence, the crystal contains both R and S isomers.

Full text of DOI:10.1016/j.poly.2014.01.035

Polyhedron 72 (2014) 157–163
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Copper(I) complexes with the triarylphosphanes
PPhn(C6H4CH2NMe2-2)3ꢀn (n = 0–2) and PPh2[C6H4CH2N(CH2CH2)2O-2].
Synthesis and structural characterization
⇑
Ancuta Covaci, Raluca Mitea, Ioana Hosu, Anca Silvestru
Faculty of Chemistry & Chemical Engineering, ‘‘Babes-Bolyai’’ University, RO-400028 Cluj-Napoca, Romania
a r t i c l e i n f o
a b s t r a c t
Article history:
Several copper(I) complexes of type [CuXPPhn(C6H4CH2NMe2-2)3ꢀn] [X = Cl, n = 1 (2), 2 (3); X = I, n = 0 (4),
1 (5), 2 (6)] were prepared by reacting CuX with the appropriate tꢀriarylphosphane in a 1:1 molar ratio.
The ionic species [Cu(MeCN)2PPh2{C6H4CH2N(CH2CH2)2O-2}]+PF6 (7) was obtained in the reaction
between [Cu(MeCN)4]PF6 and PPh2{C6H4CH2N(CH2CH2)2O-2} (1). All compounds were characterized by
NMR spectroscopy (1H and 31P) and mass spectrometry. For compound 7 the 19F NMR spectrum was also
recorded. Single-crystal X-ray diffraction studies put in evidence a P,N monometallic biconnective coor-
dination behavior of the ligand in compounds 3, 6ꢁ0.5CH2Cl2 and 7ꢁCH2Cl2, while in compound 4 a P,N,N
monometallic triconnective behavior was observed. In species 2 the unit cell contains two independent
molecules; in one of them the PN2 ligand behaves P,N,N-monometallic triconnective, while in the other as
a P,N-monometallic biconnective moiety. The N?Cu intramolecular coordination induces planar chirality
to the metal center and, as a consequence, the crystal contains both R and S isomers.
Received 12 December 2013
Accepted 24 January 2014
Available online 12 February 2014
Keywords:
Chelating triarylphosphanes
Copper complexes
Structure elucidation
Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction
NMe2-2)3] (trop = troponolate) [12] only one nitrogen atom inter-
acts with copper, while in compounds of type [Cu(L)P(C6H4CH2
ꢀ
During last years a continuously increased interest was mani-
fested to design polydentate ligands containing both phosphorus
and nitrogen donor atoms [1–8]. Such ligands may behave either
as chelating or bridging moieties towards metal centers. The
presence of both soft phosphorus and hard nitrogen in the same
molecule makes them suitable to accomodate to both soft and hard
metals. Triorganophosphanes were used as stabilizing ligands for
late transition metals and in the last two decades several species
containing organic groups with pendant arms with nitrogen donor
atoms, of general formula PPhnAr3ꢀn (Ar = C6H4CH2NMe2-2 [9–17]
and C6H3(CH2NMe2)2-3,5 [18]) were reported and their coordina-
tion behavior towards different metals was investigated. Among
them, the phosphane P(C6H4CH2NMe2-2)3 was used at a larger
scale in complexes of group 11 (Cu, Ag) metals and both mononu-
clear and dinuclear Cu(I) [9,12,14] and Ag(I) [10,12,13] complexes
were reported. The PN3 ligand usualy acts as a P,N-, or a P,N,N-
moiety in mononuclear covalent species, with one or two N?M
intramolecular interactions in addition to the phosphorusꢀmetal
bond. In [CuClP(C6H4CH2NMe2-2)3] [14] and [CuCl(trop)P(C6H4CH2
NMe2-2)3] (L = COOꢀ, CH3COOꢀ [15], ONO2 [11]) or the cation
[Cu(OClO3)P(C6H4CH2NMe2-2)3]+ [11] two N?M intramolecular
interactions are established. The nitrogen atom in the third
pendant arm was observed to be involved in N?M interactions
in the mononuclear ionic Cu(I) species [CuP(C6H4CH2NMe2-2)3]+
ClO4 [11], or in the Cu(II) species [CuClP(C6H4CH2NMe2-2)3]+
ꢀ
[CuCl2]ꢀ [14] and the dinuclear complexes of type [P(C6H4CH2
NMe2-2)3Cu2X2] (X = Cl, Br) [9,14], when the third nitrogen atom
is bridging the two copper nuclei.
While Cu(I) complexes with the phosphane P(C6H4CH2NMe2-2)3
were quite largely investigated, only one compound with the re-
lated ligand PPh2(C6H4CH2NMe2-2) was reported till now, namely
[Cu(MeCN)2PPh2(C6H4CH2NMe2-2)]+BF4ꢀ, in connection with its
catalytic activity in cyclopropanation reactions [19]. No group 11
complexes with the phosphane PPh(C6H4CH2NMe2-2)2 were re-
ported so far.
We report here about the synthesis and spectroscopic charac-
terization of several new Cu(I) complexes with ligands of type
PPhn(C6H4CH2NMe2-2)3ꢀn, as well as the ionic species [Cu(MeCN)2
{PPh2[C6H4CH2N(CH2CH2)2O-2]}]PF6 and the corresponding new
tertiary phosphane PPh2[C6H4CH2N(CH2CH2)2O-2].
⇑
Corresponding author. Tel.: +40 264 593833; fax: +40 264 590818.
E-mail address: ancas@chem.ubbcluj.ro (A. Silvestru).
http://dx.doi.org/10.1016/j.poly.2014.01.035
0277-5387/Ó 2014 Elsevier Ltd. All rights reserved.

158
A. Covaci et al. / Polyhedron 72 (2014) 157–163
precipitated as
a yellow-green microcrystalline solid. Yield:
2. Experimental
2.1. General methods
0.25 g (87.72%). M.p. 95 °C. Anal. Calc. for C24H29N2PClCu
(M = 475.48): C, 60.63; H, 6.15; N, 5.89; Found: C, 60.98; H, 6.31;
N, 5.87%; 1H NMR d 2.28 (s, 12H, NCH3), 3.40 (s, 4H, CH2N), 6.96–
7.25 (m, br., 11H, H4-6 + C6H5-ortho + meta + para), 7.74 (m, br.,
2H, H3). 31P NMR d -21.8s, br. ESI + MS, m/z (%) (CH3CN + MeOH):
439.1 (100) [PPh(C6H4CH2NMe2-2)2Cu]+, 915.2 (12) [{PPh(C6H4
CH2NMe2-2)2Cu}2Cl]+.
Compounds 3–7 were prepared similarly: [2-(dimethylamino-
methyl)phenyl]diphenylphosphane copper(I) chloride, [CuCl{PPh2(C6
H4CH2NMe2-2)}] (3) from CuCl (0.116 g, 1.17 mmol) and PPh2(C6H4
CH2NMe2-2) (0.374 g, 1.17 mmol) in CH2Cl2 (30 mL), as a pale
green solid. Yield: 0.42 g (85.71%). M.p. 255 °C. Anal. Calc. for
Starting materials, i.e. PCl3, PPh2Cl, PPhCl2, 2-Me2NCH2C6H5,
nBuLi, CuCl, CuI and [Cu(MeCN)4]PF6 were comercial products
(Aldrich) and they were used as received. The starting organic
bromide 2-O(CH2CH2)2NCH2C6H4Br [20] and the triarylphosphanes
of type PPhn(C6H4CH2NMe2-2)3ꢀn (n = 0–2) [21,22] were prepared
according to literature procedures. The solvents were dried and
freshly distilled under argon prior to use. Elemental analyses were
performed on a Flash EA 1112 machine and melting points were
measured on an Electrothermal 9200 apparatus and are not
corrected. Mass spectra (ESI + MS) were performed on a LTQ
Orbitrap - XL instrument. 1H, 19F and 31P NMR spectra were
recorded in CDCl3 solutions on a BRUKER Avance DRX 300 instru-
ment operating at 300.11 (1H), 282.23 (19F) and 121.4 MHz (31P),
respectively. The chemical shifts are reported in d units (ppm) rel-
ative to the residual peak of the deuterated solvent (Ref. CHCl3: 1H
7.26 ppm), CF3COOH and H3PO4 85%, respectively. The assignments
of the 1H chemical shifts were made according to the numbering
scheme displayed in Scheme 1, using 2D COSY NMR experiments.
The NMR spectra were processed using the MestReC and MestReN-
ova software [23].
C
21H22ClNPCu (M = 418.39): C, 60.29; H, 5.30; N 3.35; Found: C,
60.54; H, 5.63; N, 3.42%; 1H NMR: d 2.38 (s, 6H, NCH3), 3.41 (s,
3
2H, CH2N), 6.88 (t, 1H, H6, JHH 7.5 Hz), 7.28 (m, br., 2H, H4,5),
3
7.40 (m, 7H, H3 + C6H5-meta + para), 7.54 (dd, 4H, C6H5-ortho, JHH
3
7.5, JPH 10.9 Hz). 31P NMR: d ꢀ10.3s, br. ESI + MS, m/z (%)
(CH3CN + MeOH): 319.38 (100) [PPh2(C6H4CH2NMe2-2)]+, 382.07
(68) [PPh2(C6H4CH2NMe2-2)Cu]+, 799.13 (18) [PPh2(C6H4CH2
NMe2-2)Cu]2Cl+.
tris[2-(dimethylaminomethyl)phenyl]phosphane copper(I) iodide,
[CuI{P(C6H4CH2NMe2-2)3}] (4) from CuI (0.088 g, 0.46 mmol) and
P(C6H4CH2NMe2-2)3 (0.199 g, 0.46 mmol) in CH2Cl2 (30 mL), as a
yellow solid. Yield: 0.21 g (73.17%). M.p. 189 °C. Anal. Calc. for
C
27H36CuIN3P (M = 624.03): C, 51.97; H, 5.81; N 6.73; Found: C,
2.2. Synthesis
52.11; H, 5.98; N, 6.84%; 1H NMR: d 2.35 (s, 6H, NCH3), 3.73 (AB
2
spin system with dA 3.40 and dB 4.06 ppm, 4H, CH2N, JHH
2.2.1. Preparation of [{2-(N-
morpholinylmethyl)phenyl}diphenylphosphane],
PPh2[C6H4CH2N(CH2CH2)2O-2] (1)
3
3
13.2 Hz), 6.77 (t, 3H, H6, JHH 7.8 Hz); 7.19 (t, 3H, H4, JHH 7.5 Hz);
7.40 (m, 6H, H3,5). 31P NMR: d ꢀ32.3s, br. ESI + MS, m/z (%) (MeOH):
496.19 (100) [CuP(C6H4CH2NMe2-2)3]+, 624.11 (24) [CuIP(C6H4-
CH2NMe2-2)3 + H]+.
bis[2-(dimethylaminomethyl)phenyl]phenylphosphane copper(I)
iodide, [CuI{PPh(C6H4CH2NMe2-2)2}] (5) from CuI (0.101 g,
0.53 mmol) and PPh(C6H4CH2NMe2-2)2 (0.200 g, 0.53 mmol) in
CH2Cl2 (30 mL), as a yellow solid. Yield: 0.44 g (83.1%). M.p.
183 °C. Anal. Calc. for C24H29CuIN2P (M = 566.93): C, 50.85; H,
5.16; N, 4.94; Found: C, 50.74; H, 5.28; N, 4.98%; 1H NMR: d 2.41
(s, 12H, NCH3), 3.48 (AB spin system with dA 3.40 and dB
3.59 ppm, 4H, CH2N, JHH 12.3 Hz), 6.92 (t, 2H, H6, JHH 7.7 Hz),
7.26 (m, 5H, H4 + C6H5-meta + para), 7.37–7.48 (m, 4H, H5 +
C6H5-ortho), 7.64 (m, 2H, H3); 31P NMR: d ꢀ26.8s, br. ESI + MS, m/z
(%) (MeOH): 439.1 (100) [PPh(C6H4CH2NMe2-2)2Cu]+, 1007.04
(34) [{PPh(C6H4CH2NMe2-2)2Cu}2I]+.
A solution of Ph2PCl (1.75 mL, 2.151 g, 9.75 mmol) in THF
(10 mL) was added dropwise at ꢀ70 °C, under argon, to a stirred
solution of Li[C6H4CH2N(CH2CH2)2O-2] (1.786 g, 9.75 mmol) in
anhydrous THF (50 mL). The reaction mixture was stirred at
ꢀ70 °C for additional 2 h, then it was allowed to reach the room
temperature and the solvent was removed under vacuum. The re-
mained product was extracted with CH2Cl2. LiCl was filtered off
and CH2Cl2 was removed in vacuum. The remained oil was treated
with n-hexane to give the title compound as a colourless powder.
Yield: 2.79 g (79.2%). M.p. 116 °C. Anal. Calc. for C23H24NOP
(M = 361.42): C, 76.43; H, 6.69; N, 3.88; Found: C, 76.63; H, 6.42;
2
3
N, 3.74%. 1H NMR: d 2.24 (t, 4H, H8,11 3JHH 4.2 Hz), 3.08 (s, br.,
,
4H, H9,10), 3.66 (s, 2H, CH2N), 6.94 (m, 1H, H6), 7.12–7.22 (m, 7H,
H4 + C6H5-meta + para), 7.25 (m, 5H, H5 + C6H5-ortho), 7.32 (m,
1H, H3). 31P NMR: d ꢀ16.1s.
[2-(dimethylaminomethyl)phenyl]diphenylphosphane
copper(I)
iodide, [CuI{PPh2(C6H4CH2NMe2-2)}] (6) from CuI (0.121 g,
0.63 mmol) and PPh2(C6H4CH2NMe2-2) (0.201 g, 0.63 mmol) in
2.2.2. Preparation of bis[2-
(dimethylaminomethyl)phenyl]phenylphosphane copper(I) chloride,
[CuCl{PPh(C6H4CH2NMe2-2)2}] (2)
A reaction mixture of CuCl (0.059 g, 0.60 mmol) and PPh
(C6H4CH2NMe2-2)2 (0.225 g, 0.60 mmol) in THF (30 mL) was stir-
red for 2 h at room temperature. From the clear yellow solution
the solvent was removed in vacuum and the remained oily product
was treated with n-hexane (20 mL) when the title compound
CH2Cl2 (30 mL), as
a pale yellow-green solid. Yield: 0.25 g
(77.6%). M.p. 182 °C. Anal. Calc. for C21H22CuINP (M = 509.84): C,
49.47; H, 4.35; N, 2.75; Found: C, 49.63; H, 4.38; N, 2.86%; 1H
NMR: d 2.45 (s, 6H, NCH3), 3.51 (s, 2H, CH2N), 6.89 (t, 1H, H6,
3
3JHH 7.3 Hz); 7.23 (t, 1H, H4, JHH 7.2 Hz), 7.33 (m, 8H, H3,5 + C6H5-
3
3
meta + para), 7.57 (dd, 4H, C6H5-ortho, JHH 6.7, JPH 10.2 Hz). 31P
NMR: d ꢀ20.3s, br. ESI + MS, m/z (%) (CH3CN + MeOH): 319.38
(100) [PPh2(C6H4CH2NMe2-2)]+, 382.07 (24) [PPh2(C6H4CH2NMe2-2)
Cu]+, 892.77 (11) [{PPh2(C6H4CH2NMe2-2)Cu}2I]+.
[Cu(MeCN)2{PPh2[C6H4CH2N(CH2CH2)2O-2}]PF6
(7)
from
[Cu(MeCN)4]PF6 (0.352 g, 0.94 mmol) and PPh2[C6H4CH2N(CH2
CH2)2O-2] (0.340 g, 0.94 mmol) in CH2Cl2 (30 mL), as a green–blue
solid. Yield: 0.574 g (83.18%). M.p. 102 °C. Anal. Calc. for C27H30
CuF6N3OP2 (M = 652.04): C, 49.74; H, 4.64; N, 6.44; Found: C,
49.78; H, 4.72; N, 6.45%; 1H NMR: d 2.28 (s, 6H, CH3CN), 2.62 (AB
spin system, br., with dA 2.48 and dB 2.79 ppm, 4H, H8,11), 3.63 (s,
3
2H, CH2N), 3.93 (s, br., 4H, H9,10), 6.94 (t, 1H, H6, JHH 8.2 Hz),
7.35–7.73 (m, 13H, H3-5 + C6H5-ortho + meta + para). 31P NMR: d
1
Scheme 1.
ꢀ144.42 hept. (PF6, JPF 712.2 Hz), ꢀ16.28s, br. 19F NMR: d

A. Covaci et al. / Polyhedron 72 (2014) 157–163
159
1
ꢀ72.63 (d, JPF 712.2 Hz). ESI + MS, m/z (%) (MeOH): 424.09 (100)
[CuPPh2{C6H4CH2N(CH2CH2)2O}]+, 465.11 (24) [Cu(CH3CN)PPh2
{C6H4CH2N(CH2CH2)2O}]+.
2.3. Crystal structure determination of compounds 2–4, 6ꢁ0.5CH2Cl2
and 7ꢁCH2Cl2
Single-crystals of compounds 2–4, 6ꢁ0.5CH2Cl2 and 7ꢁCH2Cl2
were grown from a mixture of CH2Cl2/n-hexane (1/5, v/v). The
crystals were attached with paraton/N oil to cryoloops. Data
collection and processing was carried on a Bruker SMART APEX
Scheme 2.
CCDC system, using graphite-monochromated Mo K
(k = 0.71073 Å). Details of the crystal structure determination and
refinement for the title compoundsꢁare given in Table 1.
a
radiation
The copper(I) complexes with triarylphosphanes of type
[CuXPPhn(C6H4CH2NMe2-2)3ꢀn] (X = Cl, n = 1, 2; X = I, n = 0–2), as
well asꢀthe ionic species [Cu(MeCN)2PPh2{C6H4CH2N(CH2CH2)2O-
2}]+PF6 were prepared according to Scheme 3.
The structures were refined with anisotropic thermal parame-
ters. The hydrogen atoms were refined with a riding model and a
mutual isotropic thermal parameter. In compound 6ꢁ0.5CH2Cl2
the solvent molecules are disordered over two positions and the
hydrogen atoms of CH2Cl2 were not calculated. For structure solv-
ing and refinement was used the software package SHELX-97 [24].
The drawings were created with the Diamond program [25].
The copper complexes were isolated as yellow or green micro-
crystalline solids. All species were investigated by 1H and 31P NMR
and mass spectrometry. For compound 7 the 19F NMR spectrum
was also recorded.
The 1H NMR spectra present the expected resonances for the
organic groups attached to phosphorus and suggested the equiva-
lence of the 2-Me2NCH2C6H4 groups for each compound in
solution.
In phosphane 1 the CH2 protons in the morpholinyl ring exhibits
two resonances for the protons H8,11 and H9,10, respectively, simi-
larly with the spectra of the organic ligand 2-O(CH2CH2)2NCH2C6H5
and the corresponding bromide 2-O(CH2CH2)2NCH2C6H4Br [20],
while the methylene CH2N protons from the benzyl group present
a singlet resonance at d 3.65 ppm. In compounds 2, 3 and 6 singlet
resonances were observed for the equivalent CH2N and N(CH3)2
protons in the pendant arms, repectively. For compounds 4 and 5
3. Results and discussion
3.1. Preparation and spectroscopic characterization
The triarylphosphane 1 resulted in the reaction between the
lithiated derivative Li[C6H4CH2N(CH2CH2)2O-2], previously ob-
tained in situ by ortho-lithiation of 2-O(CH2CH2)2NCH2C6H4Br with
nBuLi, and Ph2PCl, in a 1:1 M ratio, as depicted in Scheme 2.
Table 1
Crystal data and structure refinement for [CuCl{PPh(C6H4CH2NMe2-2)2}]ꢁ(2), [CuCl{PPh2(C6H4CH2NMe2-2)}] (3), [CuI{P(C6H4CH2NMe2-2)3}]ꢁ(4) [CuI{PPh2(C6H4CH2NMe2-
2)}]ꢁ0.5CH2Cl2 (6ꢁ0.5CH2Cl2) and [Cu(CH3CN)2{PPh2[C6H4CH2N(CH2CH2)2O-2}]PF6ꢁCH2Cl2 (7ꢁCH2Cl2).
2
3
4
6ꢁ0.5CH2Cl2
7ꢁCH2Cl2
Empirical formula
Formula weight
T (K)
C24H29ClCuN2P
475.45
297(2)
C42H44Cl2Cu2N2P2
836.73
297(2)
C27H36CuIN3P
624.00
297(2)
C43H44Cl2Cu2I2N2P2
1102.54
297(2)
C28H32Cl2CuF6N3OP2
736.95
297(2)
Wavelength (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
0.71073
monoclinic
P2(1)
8.8399(9)
24.327(2)
11.2728(11)
90.00
99.643(2)
90.00
2389.9(4)
4
1.321
1.105
992
0.71073
monoclinic
P2(1)/n
8.6225(8)
14.8334(13)
15.8339(14)
90.00
93.248(2)
90.00
2021.9(3)
2
1.374
1.294
864
0.71073
monoclinic
P2(1)/c
9.1772(8)
18.0385(16)
17.1652(15)
90.00
100.809(2)
90.00
2791.2(4)
4
1.485
1.965
1264
0.71073
0.71073
triclinic
triclinic
ꢀ
ꢀ
P1
P1
9.0952(14)
11.5056(17)
12.2365(18)
106.999(2)
105.405(2)
99.419(3)
1139.4(3)
1
8.6806(8)
10.9638(10)
18.0306(16)
78.567(2)
81.215(2)
88.975(2)
1662.1(3)
2
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (g/cm3)
1.607
2.506
544
1.473
0.974
752
Absorption coefficient (mmꢀ1
F(000)
)
Crystal size (mm)
h (°)
Reflections collected
0.28 x 0.16 x 0.15
1.67 to 25.00
17374
0.38 x 0.19 x 0.15
2.58 to 25.00
14392
0.33 x 0.32 x 0.22
2.26 to 25.00
26625
0.32 x 0.26 x 0.21
1.85 to 24.99
11067
0.44 x 0.38 x 0.22
1.17 to 25.00
16162
Independent reflections (Rint
Maximum and minimum
transmissions
)
8271 (0.0705)
0.8518 and 0.7473
3558 (0.0556)
0.8295 and 0.6390
4912 (0.0511)
0.649 and 0.528
4006 (0.0259)
0.5811 and 0.4610
5843 (0.0331)
0.8142 and 0.6737
Refinement method
full-matrix least-squares on F2
Data/restraints/parameters
8271/1/531
1.011
3558/0/228
1.232
4912/0/304
1.221
4006/2/246
1.109
5843/0/390
1.063
Goodness-of-fit (GOF) on F2
Final R indicies [I > 2
R indicies (all data)
r
(I)]
R1 = 0.0755,
wR2 = 0.1460
R1 = 0.1283,
wR2 = 0.1728
0.490 and ꢀ0.382
R1 = 0.0688,
wR2 = 0.1286
R1 = 0.0827,
wR2 = 0.1333
0.564 and ꢀ0.414
R1 = 0.0536,
wR2 = 0.1078
R1 = 0.0637,
wR2 = 0.1118
0.710 and ꢀ0.423
R1 = 0.0382,
wR2 = 0.0909
R1 = 0.0439,
wR2 = 0.0936
0.704 and ꢀ0.423
R1 = 0.0726,
wR2 = 0.1986
R1 = 0.0842,
wR2 = 0.2091
0.917 and ꢀ0.811
Largest difference in peak and hole,
(e Åꢀ3
)

160
A. Covaci et al. / Polyhedron 72 (2014) 157–163
3.2. Single-crystal X-ray diffraction studies
3.2.1. Crystal and molecular structure of [CuCl{PPh(C6H4CH2NMe2-
2)2}]ꢁ(2)
The Ortep-like diagram for this species is depicted in Fig. 1 and
relevant interatomic bond lengths and angles are given in Table 2.
The compound crystallizes in the monoclinic P2(1) space group
and the crystal contains two independent molecules, 2a and 2b,
in the asymmetric unit. In molecule 2a both nitrogen atoms are
intramolecularly coordinated to copper {N(1)ꢁ ꢁ ꢁCu(1) 2.464(8)
Scheme 3.
and N(2)ꢁ ꢁ ꢁCu(1) 2.169(8) Å versus
Rrvdw(Cu,N) = 2.95 Å [28]}. In
the other one (2b) only one nitrogen atom is coordinated to copper
[N(3)ꢁ ꢁ ꢁCu(2) 2.175(8) Å, while the other nitrogen is coordinated to
the diastereotopic CH2 protons give resonances in form of AB spin
systems, while the N(CH3)2 groups give singlet resonances in each
case. This behavior suggests either the absence of any intramolec-
ular N?P or N?Cu coordination in addition to the expected PꢀCu
bond, or a very fast dynamic process involving decoordination,
inversion at the nitrogen atom and re-coordination [26], which
can not be evidenced at room temperature at the NMR time scale.
In case of compound 7 the 1H NMR spectrum is more complex. At
room temperature in the aliphatic region were identified four res-
onances: singlet resonances assigned to CH3CN (d 2.28 ppm), CH2N
(d 3.63 ppm), and (CH2)2O (H9,10, broad, d 3.93 ppm) protons, as
well as a broad AB spin system centered at 2.62 ppm (with dA
phosphorus {N(4)ꢁ ꢁ ꢁP(2) 3.032(9) Å,
versus Rrvdw(P,N) = 3.40 Å
[29]}.
The intramolecular N?Cu and N?P intramolecular coordination
induces planar chirality and therefore the compound crystalizes as a
mixture of isomers, RN1,RN2 and SN1,SN2 for molecule 2a and SN3,RN4
and RN3,SN4 for molecule 2b, respectively. Moreover, due to the
N?P intramolecular coordination the P(2) atom becomes also
chiral, and therefore the chirality to this atom determines the for-
mation of CP2 and AP2 isomers [30]. Finally, the isomers correspond-
ing to the molecule 2b can be described as SN3,RN4,CP2 and
RN3,SN4,AP2. The presence of both isomers is most likely to be due
to a 50:50 inversion twin, as suggested by the Flack parameter re-
fined to the value 0.48(2). The coordination geometry about copper
and phosphorus in molecule 2a is distorted tetrahedral, while in
case of molecule 2b, the coordination geometry about copper is dis-
torted trigonal planar and about P(2) it is a distorted trigonal bipyr-
amid, with C(25) and N(4) in apices [C(25)ꢀP(2)ꢀN(4) 170.50(3)°].
P(2) is displayed at 0.44 Å above the Cu(2)/C(34)/C(43) trigonal
plane. The six-membered metallacycles have boat conformations
in both molecules, with P(1) and C(7) [dihedral angles
2.48 and dB 2.79 ppm), corresponding to the N(CH2)2 (H8,11
)
protons in the morpholinyl ring. This might be the result of a dy-
namic behavior in solution, as described above, to which contrib-
utes also a fast conformational exchange of the six-membered
morpholinyl ring. The ratio of the integrals in the 1H NMR spec-
trum of compound 7 corresponds to the given formula and it is
in accordance with the solid state structure determined by sin-
gle-crystal X-ray diffraction (see subsequent discussion). For com-
pounds 2–6 one singlet resonance was observed in their 31P NMR
spectra, slightly shifted in comparison with the corresponding free
phosphanes: ꢀ14.8 for PPh2(C6H4CH2NMe2-2), ꢀ24.7 for PPh(C6H4
CH2NMe2-2)2 and ꢀ35.3 ppm for P(C6H4CH2NMe2-2)3, in CDCl3
[21,22,27]. In case of compound 7 also the resonance correspond-
N(1)C(2)C(7)/N(1)C(2)C(1)Cu(1)
71.90°
and
P(1)C(1)Cu(1)/
N(1)C(2)C(1)Cu(1) 22.66°] and P(1) and C(16) [dihedral angles
N(2)C(16)C(11)/N(2)C(11)C(10)Cu(1) 57.45° and P(1)C(10)Cu(1)/
N(2)C(11)C(10)Cu(1) 28.89°] in molecule 2a and P(2) and C(31)
[dihedral angles N(3)C(26)C(31)/N(3)C(26)C(25)Cu(2) 59.79° and
P(2)C(25)Cu(2)/N(3)C(26)C(25)Cu(2) 40.16°] in molecule 2b,
respectively, in apices.
ing to the PF6 anion is present as a heptet, due to the 31Pꢀ19F
ꢀ
coupling.
All compounds present in their ESI+ mass spectra the corre-
sponding cations of type [CuPPhnR3ꢀn
+
]
[R = 2-Me2NCH2C6H4 or
2-O(CH2CH2)2NCH2C6H4]. The peaks at m/z values corresponding
to the formula [(CuPPhnR3ꢀn)2X]+ (X = Cl, I) suggest dimeric associ-
ations in compounds 2, 3, 5 and 6. For compounds 3 and 6 a di-
meric structure was found in solid state by single-crystal X-ray
diffraction.
3.2.2. Crystal and molecular structure of [CuCl{PPh2(C6H4CH2NMe2-2)}]
(3) and [CuI{PPh2(C6H4CH2NMe2-2)}]ꢁ0.5 CH2Cl2 (6ꢁ0.5CH2Cl2)
The ORTEP-like diagrams with the corresponding numbering
schemes for the title compounds are given in Figs. 2 and 3, while
relevant bond distances and angles are given in Table 3.
Compound 3 crystallizes in the monoclinic P2(1)/n space group,
ꢀ
while compound 6ꢁ0.5CH2Cl2 in the triclinic P1 space group. The
nitrogen atom in the pendant arm is intramolecularly coordinated
to copper [N(1)ꢁ ꢁ ꢁCu(1) 2.172(4) Å]. In this way a six-membered
metallacycle is formed. In both compounds the chelate ring has a
boat conformation, with P(1) and C(7) in apices [dihedral angles
Cu(1)P(1)C(1)/Cu(1)C(1)C(2)N(1)
Cu(1)C(1)C(2)N(1) 63.77°
22.63°
and
and
N(1)C(2)C(7)/
Cu(1)P(1)C(1)/
in
3
Cu(1)C(1)C(2)N(1) 48.22° and N(1)C(2)C(7)/Cu(1)C(1)C(2)N(1)
51.57° in 6ꢁ0.5CH2Cl2]. Due to the planar chirality determined by
the intramolecular N?Cu coordination, the compounds crystallize
as a mixture of R and S isomers which are associated in dimeric
units (Fig. 3) by bridging halogen atoms {Cl(1)ꢁ ꢁ ꢁCu(10)
2.3406(13) Å, I(1)ꢁ ꢁ ꢁCu(10) 2.5950(7) Å versus
RrvdW(Cu,Cl) 3.20
RrvdW(Cu,I) 3.55 Å [28,29]}. Thus a tricyclic system is formed,
and
with a planar Cu2X2 core. The ligands are oriented trans each other,
with respect to the relative positions of the nitrogen and phospho-
rus atoms to the planar Cu2X2 core. The coordination geometry
about copper is distorted tetrahedral.
Fig. 1. ORTEP-like representation at 30% probability and atom numbering scheme
for the isomers RN1,RN2-2a and SN3,RN4,CP2-2b (hydrogen atoms are omitted for
clarity).

A. Covaci et al. / Polyhedron 72 (2014) 157–163
161
Table 2
Relevant interatomic distances (Å) and angles (°) for [CuCl{PPh(C6H4CH2NMe2-2)2}]ꢁ(2), and [CuI{P(C6H4CH2NMe2-2)3}]ꢁ(4).
2a
2b
4
Cu1ꢀCl1
2.213(3)
2.150(2
Cu2ꢀCl2
2.157(3)
2.183(2)
2.175(8)
3.032(9)
1.840(9)
1.848(9)
1.812(9)
99.7(3)
151.49(12)
108.9(3)
104.3(4)
107.8(4)
102.4(4)
119.8(3)
102.5(3)
117.4(3)
170.50(3)
Cu1ꢀI1
2.5622(7)
2.1980(13)
2.309(5)
2.170(4)
1.837(5)
Cu1ꢀP1
Cu2ꢀP2
Cu1ꢀP1
Cu1ꢀN1
2.464(8)
2.169(8)
1.806(8)
1.864(8)
1.830(9)
94.3(2)
Cu2ꢀN3
Cu1ꢀN1
Cu1ꢀN2
P2ꢁ ꢁ ꢁN4
Cu1ꢀN2
P1ꢀC1
P2ꢀC25
P1ꢀC1
P1ꢀC10
P2ꢀC34
P1ꢀC10
1.839(5)
1.837(5)
P1ꢀC19
P2ꢀC43
P1ꢀC19
P1ꢀCu1ꢀN1
P1ꢀCu1ꢀN2
P1ꢀCu1ꢀCl1
N1ꢀCu1ꢀCl1
N2ꢀCu1ꢀCl1
N2ꢀCu1ꢀN1
C1ꢀP1ꢀC19
C1ꢀP1ꢀC10
C10ꢀP1ꢀC19
C1ꢀP1ꢀCu1
C10ꢀP1ꢀCu1
C19ꢀP1ꢀCu1
P2ꢀCu2ꢀN3
P2ꢀCu2ꢀCl2
N3ꢀCu2ꢀCl2
C43ꢀP2ꢀC25
C43ꢀP2ꢀC34
C25ꢀP2ꢀC34
C43ꢀP2ꢀCu2
C25ꢀP2ꢀCu2
C34ꢀP2ꢀCu2
C25ꢀP2ꢀN4
P1ꢀCu1ꢀN1
P1ꢀCu1ꢀN2
P1ꢀCu1ꢀI1
N1ꢀCu1ꢀI1
N2ꢀCu1ꢀI1
N2ꢀCu1ꢀN1
C1ꢀP1ꢀC19
C1ꢀP1ꢀC10
C10ꢀP1ꢀC19
C1ꢀP1ꢀCu1
C10ꢀP1ꢀCu1
C19ꢀP1ꢀCu1
96.17(12)
98.34(12)
135.90(4)
107.94(11)
104.93(13)
113.08(18)
103.7(2)
102.5(2)
105.0(2)
110.88(16)
111.39(16)
121.52(15)
99.3(2)
138.05(10)
106.4(2)
108.2(2)
107.6(3)
103.0(4)
103.9(4)
103.8(4)
113.2(3)
108.8(3)
122.3(3)
[Cu(1)ꢁ ꢁ ꢁN(1) 2.153(2) Å], in case of the copper iodide adduct two
strong N?Cu interactions are established [N(1)ꢁ ꢁ ꢁCu(1) 2.309(5),
N(2)ꢁ ꢁ ꢁCu(1) 2.170(4) Å]. The third pendant arm remains
uncoordinated, and in this way distorted tetrahedral environments
resulted about copper and phosphorus. Due to the planar chirality
induced to the metal center by both N?Cu interactions, the
compound crystallizes as a mixture of SN1,SN2 and RN1,RN2 isomers.
The two six membered rings have boat conformations with C(7)/
P(1) and C(16)/P(1) atoms, respectively, in apices, [dihedral
angles Cu(1)P(1)C(1)/Cu(1)C(1)C(2)N(1) 17.44° and N(1)C(7)C(2)/
Cu(1)C(1)C(2)N(1) 72.02° and Cu(1)P(1)C(10)/Cu(1)C(10)C(11)
N(2) 15.82° and N(2)C(16)C(11)/Cu(1)C(10)C(11)N(2) 62.66°,
respectively].
Fig. 2. ORTEP-like representation at 50% probability and atom numbering scheme
for the isomer SN1-3 (hydrogen atoms are omitted for clarity).
3.2.4. Crystal and molecular structure of
[Cu(CH3CN)2{PPh2[C6H4CH2N(CH2CH2)2O-2]}]PF6ꢁCH2Cl2 (7ꢁCH2Cl2)
ꢀ
Compound 7ꢁCH2Cl2 crystallizes in the triclinic P1 space group.
The ORTEP-like diagram with the atoms numbering scheme is gi-
ven in Fig. 5, while important bond distances and angles are given
in Table 3.
The title compound has a ionic structure with discrete [Cu(CH3
CN)2{PPh2[C6H4CH2N(CH2CH2)2O-2]}]+ cations and PF6ꢀ anions. No
copper ꢀ fluorine distance in the range of the sum of the respective
van der Waals radii [RrvdW(Cu,F) 2.94 Å [29] was observed. The
structure of the cation resambles that one described for the related
[Cu(CH3CN)2{PPh2(C6H4CH2NMe2-2)]+ [19], with a distorted tetra-
hedral coordination geometry about copper. The intramolecular
Me2N?Cu interaction [N(1)ꢁ ꢁ ꢁCu(1) 2.175(4) Å] is in the range
found for other related copper complexes with triarylphosphanes
with organic groups with pendant arms, either previously reported
or discussed in this paper [range 2.0835(5)ꢀ2.464(8) Å]
[9,11,12,14,15,19]. The other two copperꢀnitrogen distances
[Cu(1)ꢀN(2) 2.037(4) and Cu(1)ꢀN(3) 1.996(5) Å] are of similar
magnitude as in the related cation [Cu(CH3CN)2{PPh2(C6H4CH2
NMe2-2)]+ [2.020(7) and 1.974(7) Å] [19]. The six membered
CuNC3P chelate ring has a boat conformation with C(7) and P(1)
in apices [dihedral angles Cu(1)P(1)C(1)/Cu(1)C(1)C(2)N(1) 20.51°
and N(1)C(7)C(2)/Cu(1)C(1)C(2)N(1) 67.24°], while the morpholi-
nyl ring has a chair conformation, with N(1) and O(1) in apices.
Due to the planar chirality determined by the N?Cu intramolecu-
lar interaction, as in the previously discussed species, the crystal
contains a mixture of R and S isomers.
0
Fig. 3. Dimeric association of SN1 and RN1 isomers in the crystal of 6ꢁ0.5CH2Cl2,
based on Cuꢁ ꢁ ꢁI interactions (hydrogen atoms are omitted for clarity).
3.2.3. Crystal and molecular structure of [CuI{P(C6H4CH2NMe2-
2)3}]ꢁ(4)
Compound 4 crystallizes in the monoclinic P2(1)/c space group.
The ORTEP-like diagram with the numbering scheme is depicted in
Fig. 4, while important bond distances and angles are given in
Table 2.
The crystal consists of discrete molecules separated by normal
van der Waals distances. By contrast with the already reported
species [CuCl{P(C6H4CH2NMe2-2)3}] [14] in which only one
pendant arm is intramolecularly coordinated to copper

162
A. Covaci et al. / Polyhedron 72 (2014) 157–163
Table 3
Relevant interatomic distances (Å) and angles (°) for [CuCl{PPh2(C6H4CH2NMe2-2)}] (3), [CuI{PPh2(C6H4CH2NMe2-2)}]ꢁ0.5CH2Cl2 (6ꢁ0.5CH2Cl2) and [Cu(CH3CN)2{PPh2[C6H4CH2-
N(CH2CH2)2O-2}]PF6ꢁCH2Cl2 (7ꢁCH2Cl2).
3a
6ꢁ0.5CH2Cl2
7ꢁCH2Cl2
a
Cu1ꢀCl1
2.3625(13)
2.3406(13)
2.1768(13)
2.172(4)
1.832(5)
1.839(5)
Cu1ꢀI1
2.6973(7)
2.5950(7)
2.2410(12)
2.210(4)
1.831(4)
1.832(4)
Cu1ꢀN1
2.175(4)
2.037(4)
1.996(5)
2.2186(12)
1.823(4)
1.824(5)
Cu1ꢀCl10
Cu1ꢀI10
Cu1ꢀN2
Cu1ꢀP1
Cu1ꢀP1
Cu1ꢀN3
Cu1ꢀN1
Cu1ꢀN1
Cu1ꢀP1
P1ꢀC1
P1ꢀC1
P1ꢀC1
P1ꢀC10
P1ꢀC10
P1ꢀC12
P1ꢀC16
1.828(5)
P1ꢀC16
1.827(4)
P1ꢀC18
1.822(5)
P1ꢀCu1ꢀN1
N1ꢀCu1ꢀCl1
P1ꢀCu1ꢀCl1
P1ꢀCu1ꢀCl10
N1ꢀCu1ꢀCl10
Cl1ꢀCu1ꢀCl10
C1ꢀP1ꢀC16
C1ꢀP1ꢀC10
C10ꢀP1ꢀC16
C1ꢀP1ꢀCu1
C10ꢀP1ꢀCu1
C16ꢀP1ꢀCu1
Cu1ꢀCl1ꢀCu10
99.93(12)
107.37(12)
118.70(5)
125.33(5)
103.40(12)
100.19(4)
105.1(2)
102.2(2)
104.2(2)
108.71(16)
118.84(15)
116.14(16)
79.81(4)
P1ꢀCu1ꢀN1
N1ꢀCu1ꢀI1
P1ꢀCu1ꢀI1
P1ꢀCu1ꢀI10
N1ꢀCu1ꢀI10
I1ꢀCu1ꢀI10
C1ꢀP1ꢀC16
C1ꢀP1ꢀC10
C10ꢀP1ꢀC16
C1ꢀP1ꢀCu1
C10ꢀP1ꢀCu1
C16ꢀP1ꢀCu1
Cu1ꢀI1ꢀCu10
96.27(11)
105.72(11)
108.05(4)
122.75(4)
110.08(10)
111.82(2)
103.8(2)
106.11(19)
101.87(19)
101.33(14)
122.18(14)
119.52(14)
68.18(2)
P1ꢀCu1ꢀN1
P1ꢀCu1ꢀN2
P1ꢀCu1ꢀN3
N3ꢀCu1ꢀN2
N1ꢀCu1ꢀN2
N3ꢀCu1ꢀN1
C1ꢀP1ꢀC18
C1ꢀP1ꢀC12
C12ꢀP1ꢀC18
C1ꢀP1ꢀCu1
C12ꢀP1ꢀCu1
C18ꢀP1ꢀCu1
99.29(11)
116.43(13)
118.52(13)
102.13(18)
102.51(16)
117.53(16)
103.4(2)
103.1(2)
104.6(2)
109.04(15)
117.56(15)
117.33(15)
a
Symmetry equivalent position 2 – x, 1 ꢀ y and 2 ꢀ z in 3 and ꢀx, 1 ꢀ y and 1 ꢀ z in 6ꢁ0.5CH2Cl2 are given by ‘‘prime’’.
due to the additional N?Cu intramolecular interactions estab-
lished at least in solid state. For the compound [CuClPPh(C6H4CH2
NMe2-2)2] (2) two independent molecules were observed in the
unit cell, in one of them both nitrogen atoms interacting with cop-
per, while in the other one only one pendant arm is involved in
such an interaction and the other nitrogen is intramolecularly
coordinated to phosphorus. In the compound [CuIP(C6H4CH2NMe2-
2)3] (4) two nitrogen atoms are coordinated to copper, while the
third one remained dangling. The NMR studies didn’t bring any
evidence for the intramolecular N?Cu or N?P intramolecular
interaction in solution, at room temperature, and this might be
in accordance with a fast dynamic process involving decoordina-
tion, inversion at the nitrogen atom and recoordination.
Fig. 4. ORTEP-like representation at 30% probability and atom numbering scheme
for isomer SN1,SN2-4 (hydrogen atoms are omitted for clarity).
Acknowledgements
Financial support from the Ministry of Education and Research
of Romania (CNCS, Research Project No. PN-II-ID-PCE-2011-3-
0659) is greatly appreciated.
Appendix A. Supplementary material
Crystallographic data for the structural analyses have been
deposited with the Cambridge Crystallographic Data Centre, CCDC
Nos. 974483, 974484, 974485, 974486 and 974487 for 2, 7ꢁCH2Cl2,
6ꢁ0.5CH2Cl2, 4 and 3, respectively. Copies of this information may
be obtained free of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: +44-1223-336-033; e-mail: depos-
it@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
References
Fig. 5. ORTEP-like representation at 30% probability and atom numbering scheme
for the isomer RN1-7 (hydrogen atoms are omitted for clarity).
[1] S. Maggini, Coord. Chem. Rev. 253 (2009) 1793. and references therein.
[2] J.D. Woollins, Phosphorus, Sulfur, Silicon Relat. Elem. 168 (2001) 1.
[3] L.M. Clarke, A.M.Z. Slawin, J.D. Woollins, Phosphorus, Sulfur, Silicon Relat Elem.
169 (2001) 5.
[4] P.R. Elowe, C. McCann, P.G. Pringle, S.K. Spitzmesser, J.E. Bercaw,
Organometallics 25 (2006) 5255.
4. Conclusions
[5] L.-C. Liang, Coord. Chem. Rev. 250 (2006) 1152. and references therein.
[6] T.Q. Ly, J.D. Woollins, Coord. Chem. Rev. 176 (1998) 451.
[7] G.G. Briand, T. Chivers, M. Krahn, Coord. Chem. Rev. 233–234 (2002) 237.
[8] Z. Fei, P.J. Dyson, Coord. Chem. Rev. 249 (2005) 2056.
[9] H. Lang, M. Leschke, H.A. Mayer, M. Melter, C. Weber, G. Rheinwald, O. Walter,
G. Huttner, Inorg. Chim. Acta 324 (2001) 266.
Our studies upon several copper complexes with the tertiary
phosphanes PPhn(C6H4CH2NMe2-2)3ꢀn (n = 0–2) and PPh2[C6H4
CH2N(CH2CH2)2O-2], respectively, revealed either a bidentate P,N
or a tridentate P,N,N coordination behavior of the PN1-3 ligands

A. Covaci et al. / Polyhedron 72 (2014) 157–163
163
[10] H. Lang, M. Leschke, G. Rheinwald, M. Melter, Inorg. Chem. Commun. 1 (1998)
254.
[20] A.G. Avent, P.B. Hitchcock, G.J. Leigh, M. Togrou, J. Organomet. Chem. 669
(2003) 87.
[11] M. Leschke, M. Melter, B. Walfort, A. Driess, G. Huttner, H. Lang, Z. Anorg.
Allg.Chem. 630 (2004) 2022.
[21] M.A. Alonso, J.A. Casares, P. Espinet, K. Soulantica, A.G. Orpen, H. Phetmung,
Inorg. Chem. 42 (2003) 3856.
[12] H. Lang, M. Leschke, M. Melter, B. Walfort, K. Kohler, S.E. Schulz, T. Gessner, Z.
Anorg. Allg.Chem. 629 (2003) 2371.
[22] A. Chandrasekaran, N.V. Timosheva, R.O. Day, R.R. Holmes, Inorg. Chem. 41
(2002) 5235.
[13] M. Leschke, M. Melter, C. Weber, G. Rheinwald, H. Lang, Z. Anorg. Allg.Chem.
627 (2001) 1199.
[23] MestReC and MestReNova, Mestrelab Research S.L., A Coruña 15706, Santiago
de Compostela.
[14] M. Leschke, H. Lang, M. Melter, G. Rheinwald, C. Weber, H.A. Mayer, H.
Pritzkow, L. Zsolnai, A. Driess, G. Huttner, Z. Anorg. Allg. Chem. 628 (2002) 349.
[15] H. Lang, Y. Shen, T. Ruffer, B. Walfort, Inorg. Chim. Acta 361 (2008) 95.
[16] M. Leschke, G. Rheinwald, H. Lang, Z. Anorg. Allg. Chem. 628 (2002) 2470.
[17] Y. Shen, H. Pritzkow, B. Walfort, T. Ruffer, H. Lang, Acta Crystallogr., Sect. E 60
(2004) m91.
[18] R. Kreiter, J.J. Firet, M.J.J. Ruts, M. Lutz, A.L. Spek, R.J.M. Klein Gebbink, G. Van
Koten, J. Organomet. Chem. 691 (2006) 422.
[19] J. Green, E. Sinn, S. Woodward, Polyhedron 12 (1993) 991.
[24] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112.
[25] K. Brandenburg, DIAMOND – Visual Crystal Structure Information System,
Release 3.1d, Crystal Impact GbR, Bonn, Germany, 2006.
[26] M. Iwaoka, S. Tomoda, J. Am. Chem. Soc. 118 (1996) 8077.
[27] J.G. Fierro-Arias, R. Redon, J.J. Garcia, S. Hernandez-Ortega, R.A. Toscano, D.
Morales-Morales, J. Mol. Catal. A: Chem. 233 (2005) 17.
[28] J.E. Huheey, Inorganic Chemistry, Walter de Gruyter, Berlin, 1988. p. 278.
[29] J. Emsley, Die Elemente, Walter de Gruyter, Berlin, 1994.
[30] IUPAC Nomenclature of Organic Chemistry, Pergamon Press, Oxford, 1979.