Displacement of triphenylphosphine from Cu(PPh3)2NO3 and Co(PPh3)2Cl2 by a diselenoimidodiphosphinato ligand. X-ray crystal structure of (PPh3)Cu[Ph2P(Se)NP(Se)Ph2] and Co[Ph2P(Se)NP(Se)Ph2]2 containing the novel CuSe2P2N and CoSe2P2N inorganic metallocycles

Article abstract of DOI:10.1016/s0020-1693(99)00154-1

The reaction of Cu(PPh₃)₂NO₃ with K[Ph₂P(Se)-N-P(Se)Ph₂] produced a tricoordinate copper(I) complex, Cu(PPh₃)[Ph₂P(Se)-N-P(Se)Ph₂], containing the novel inorganic (carbon-free) CuSe₂P₂N metallocycle. The same diselenium reagent gave with Co(PPh₃)₂Cl₂ a spirobicyclic compound Co[Ph₂P(Se)-N-P(Se)Ph₂]₂, containing the novel inorganic CoSe₂P₂N metallocycle. The crystal structure of the two compounds was investigated by X-ray diffraction. In both compounds the inorganic metallocycles are nonplanar and display strongly distorted twisted boat conformations.

Full text of DOI:10.1016/s0020-1693(99)00154-1

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 290 (1999) 256–260
Note
Displacement of triphenylphosphine from Cu(PPh3)2NO3 and
Co(PPh3)2Cl2 by a diselenoimidodiphosphinato ligand. X-ray
crystal structure of (PPh3)Cu[Ph2P(Se)NP(Se)Ph2] and
Co[Ph2P(Se)NP(Se)Ph2]2 containing the novel CuSe2P2N and
CoSe2P2N inorganic metallocycles
Josef Novosad a,*, Marek Necas a, Jaromir Marek a, Panagiotis Veltsistas b,
Christos Papadimitriou b, Ionel Haiduc c, Makoto Watanabe d, J. Derek Woollins e
a Department of Inorganic Chemistry, Faculty of Science, Masaryk Uni6ersity, Kotlarska 2, 611 37 Brno, Czech Republic
b Department of Chemistry, Uni6ersity of Ioannina, Ioannina, Greece
c Facultatea de Chimie, Uni6ersitatea Babes-Bolyai, RO-3400 Cluj-Napoca, Romania
d College of Engineering, Chubu Uni6ersity, Kasugai, Aichi 487-8501, Japan
e Department of Chemistry, Loughborough Uni6ersity, Loughborough, Leicestershire LE11 3TU, UK
Received 7 October 1998; accepted 15 March 1999
Abstract
The reaction of Cu(PPh3)2NO3 with K[Ph2P(Se)–N–P(Se)Ph2] produced
a
tricoordinate copper(I) complex,
Cu(PPh3)[Ph2P(Se)–N–P(Se)Ph2], containing the novel inorganic (carbon-free) CuSe2P2N metallocycle. The same diselenium
reagent gave with Co(PPh3)2Cl2 a spirobicyclic compound Co[Ph2P(Se)–N–P(Se)Ph2]2, containing the novel inorganic CoSe2P2N
metallocycle. The crystal structure of the two compounds was investigated by X-ray diffraction. In both compounds the inorganic
metallocycles are nonplanar and display strongly distorted twisted boat conformations. © 1999 Elsevier Science S.A. All rights
reserved.
Keywords: Crystal structures; Copper complexes; Diselenoimidodiphosphinato complexes
interest in their complexes has been renewed and dioxo
[8–15], dithio [16–27], and even mixed oxo-thio [28–
1. Introduction
30] derivatives have been investigated. Although known
for several years [31], diselenoimidodiphosphinate has
been only recently used as a ligand [32–37].
All dichalcogenoimidodisphosphinates 1 tend to form
six-membered inorganic (carbon-free) chelate rings 2
and seldom act as bridging ligands; only the dithioimi-
dodiphosphinates are known to form larger bimetallic
rings 3 (R=Ph, M=Au [38], TePh [39], TeC6H4OCH3
Dichalcogenoimidodiphosphinato anions [R2P(E)–
N–P(E)R2]− (E=O, S, Se) are versatile ligands, with a
strong tendency to form inorganic (carbon-free) chelate
rings [1–4]. For many years after their introduction by
Schmidpeter et al. [5–7], dichalcogenoimidodisphosphi-
nates received only scant attention, but recently the
[40]) and only one example is known when
supramolecular helical polymer 4 (R=Ph, M=SnMe3)
a
* Corresponding author. Tel.: +420-5-4112 9325; fax: +420-5-
4121 1214.
E-mail address: novosad@chemi.muni.cz (J. Novosad)
is formed via secondary M···S interactions [41].
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00154-1

J. No6osad et al. / Inorganica Chimica Acta 290 (1999) 256–260
257
contains a new inorganic (carbon-free) CuSe2P2N
chelate ring 5 in which copper(I) is three-coordinate.
Complex 5 is a colourless crystalline solid (m.p.
223°C), moderately soluble in common organic
solvents.
In the reaction of bis(triphenylphosphine)cobalt(II)
dichloride with potassium tetraphenyldiselenoimido-
diphosphinate, the halogens were metathetically ex-
changed for two diselenoimidodiphosphinato ligands.
The chelate ring closure with two ligands, resulting in a
four-coordinate complex, requires two additional coor-
dination sites, and thus both triphenylphosphine
molecules are liberated (Eq. (2)). No five- or six-coordi-
nate complex containing coordinated triphenylphos-
phine was obtained in this reaction.
The discovery of heterogeometrism [42] in some
dichalcogenoimidodiphosphinates, i.e. isomeric square
pyramidal and square planar tin(II) diselenoimi-
dodiphosphinates [35], illustrates another feature of
interest in the structural chemistry of these complexes:
the possibility of (unpredictable) major structural
changes (even in the coordination geometry) produced
by minor variations in the composition of the ligand
(e.g. differing peripheral groups) within a series of
compounds containing the same metal as coordination
centre. With differing donor properties of the atoms
(oxygen, sulfur or selenium) at the two ends of the
diphosphazene fragment, the comparison of the struc-
tures and properties of various dichalcogenoimido-
diphosphinato ligands becomes interesting.
Co(PPh3)2Cl2+2K[Ph2P(Se)–N–P(Se)Ph2]
“Co[Ph2P(Se)–N–P(Se)Ph2]2+2PPh3+2KCl
(2)
Since few diselenoimidodiphosphinato metal chelates
have been investigated so far, we found it worthwhile to
extend this class of compounds. We now report cop-
per(I) and cobalt(II) diselenoimidodiphosphinates, pre-
pared and investigated for comparison with the
corresponding thio analogues.
The resulting compound is a bis(chelate) complex 6,
which can also be described as a spirobicyclic com-
pound consisting of two inorganic (carbon-free)
CoSe2P2N rings, sharing a tetrahedral cobalt(II) atom
as a coordination centre.
2. Results and discussion
It appears that the diselenoimidodiphosphinate is a
strong complexing reagent, able to displace coordinated
triphenylphosphine, when the geometric and chemical
requirements of chelate ring formation allow it. Thus,
bis(triphenylphosphine)copper(I) nitrate reacts with
potassium tetraphenyldiselenoimidodiphosphinate, to
Complex 6 is a colourless crystalline solid, moder-
ately soluble in common organic solvents and can be
recrystallized from methylene dichloride.
give
(triphenylphosphine)
(tetraphenyldiselenoimi-
Partial or complete displacement of triphenylphos-
phine by tetraphenyldiselenoimidodiphosphinate has
also been observed in reactions with Re(PPh3)2OCl3
[32], Re(PPh3)2NCl and Re(PPh3)2(NMe)Cl3 [33], but
not with [M(PMe2Ph)Cl2 (M=Pd, Pt) [33]. Similar
reactions also occur with tetraphenyldithioimidodiphos-
phinate [33]. Obviously, in all these cases the preferred
coordination geometry of the central metal atom dic-
tates the reaction path and the composition of the final
product.
dodiphosphinato)copper(I) as a result of combined
metathetical anion exchange and displacement of a
triphenylphosphine molecule (Eq. (1)):
Cu(PPh3)2NO3+K[Ph2P(Se)–N–P(Se)Ph2]
“Cu(PPh3)[Ph2P(Se)–N–P(Se)Ph2]+PPh3+KNO3
(1)
The chelate ring compound formed in reaction (1)

258
J. No6osad et al. / Inorganica Chimica Acta 290 (1999) 256–260
Table 2
,
Deviations (A) of the ring atoms from the best plane in the CuSe2P2N
ring
N
Cu
0.046(8)
0.009(2)
P(1)
P(2)
Se(1)
Se(2)
−0.694(3)
0.747(3)
0.209(2)
−0.242(2)
scheme and important interatomic distances and bond
angles are listed in Table 1.
The six-membered CuSe2P2N ring is nonplanar
(twisted boat conformation). The deviations of the ring
atoms from the weighted least-squares best plane are
listed in Table 2. The three-coordinate copper(I) atom
displays a distorted trigonal planar geometry with
Fig. 1. An ORTEP diagram of the molecular structure of 5.
P(3)–Cu–Se(1)=115.62(7)°,
P(3)–Cu–Se(2)=
122.90(7)° and Se(1)–Cu–Se(2)=121.48(6)°. This dis-
tortion is somewhat similar to that observed in the
copper(I) thio analogue Cu(PPh3)2[Ph2P(S)–N–
P(S)Ph2] with P–Cu–S=126.1(1) and 112.2(1)° and
S–Cu–S=121.5(1)°.
The molecular structures of both 5 and 6 were deter-
mined by single-crystal X-ray diffraction. An ORTEP
diagram of the molecular structure of the copper com-
pound 5 is shown in Fig. 1 with the atom numbering
The ring is basically symmetric. Thus, the selenium–
copper bonds are practically equal in the six-membered
,
ring [Cu–Se 2.3918(14) and 2.376(2) A] and so are the
Table 1
,
phosphorus–selenium bonds [P(1)–Se(1)=2.166(2) A
,
Selected bond lengths (A) and angles (°) in compounds 5 and 6
,
and P(2)–Se(2)=2.163(2) A].
The P–N bonds are also equal within the e.s.d.
Compound 5
Compound 6
,
[P(1)–N=1.600(7) and P(2)–N=1.592(7) A] and these
,
Bond lengths (A)
Cu–Se(1)
Cu–Se(2)
interatomic distances suggest some double-bond char-
acter as in other inorganic (carbon-free) metallocycles
derived from dichalcogenoimidodiphosphinates.
2.3918(14)
2.376(2)
2.222(2)
Co–Se(1)
Co–Se(2)
Co–Se(3)
Co–Se(4)
P(1)–Se(1)
P(2)–Se(2)
P(3)–Se(3)
P(4)–Se(4)
P(1)–N(1)
P(2)–N(1)
P(3)–N(2)
P(4)–N(2)
2.4746(10)
2.3622(10)
2.4394(8)
2.3835(11)
2.0992(14)
2.1913(13)
2.2056(14)
2.1640(13)
1.577(7)
Cu–P(3)
An ORTEP diagram of the molecular structure of
the cobalt(II) compound 6 is shown in Fig. 2, with the
atom numbering scheme. Significant interatomic dis-
tances and bond angles are listed in Table 1.
The six-membered CoSe2P2N rings are nonplanar
and severely distorted, displaying twisted boat confor-
P(1)–Se(1)
P(2)–Se(2)
2.166(2)
2.163(2)
P(1)–N
P(2)–N
1.600(7)
1.592(7)
1.609(4)
1.532(4)
1.575(4)
Bond angles (°)
Cu–Se(1)–P(1)
Cu–Se(2)–P(2)
92.16(7)
90.22(7)
Co–Se(1)–P(1)
Co–Se(2)–P(2)
Co–Se(3)–P(3)
Co–Se(4)–P(4)
Se(1)–Co–Se(2)
Se(1)–Co–Se(3)
Se(1)–Co–Se(4)
Se(2)–Co–Se(3)
Se(2)–Co–Se(4)
Se(3)–Co–Se(4)
N(1)–P(1)–Se(1)
N(1)–P(2)–Se(2)
N(2)–P(3)–Se(3)
N(2)–P(4)–Se(4)
P(1)–N–P(2)
97.91(4)
98.21(4)
97.00(4)
103.33(4)
113.38(3)
111.55(3)
106.18(3)
106.91(3)
104.72(4)
114.06(3)
115.0(2)
119.7(2)
117.9(2)
120.7(2)
130.3(3)
133.1(3)
Se(1)–Cu–Se(2) 121.48(6)
P(3)–Cu–Se(1)
P(3)–Cu–Se(3)
115.62(7)
122.90(7)
N–P(1)–Se(1)
N–P(2)–Se(2)
116.9(3)
118.1(3)
P(1)–N–P(2)
127.0(4)
P(3)–N–P(4)
Fig. 2. An ORTEP diagram of the molecular structure of 6.

J. No6osad et al. / Inorganica Chimica Acta 290 (1999) 256–260
259
mation imposed by the non-parallel orientation of the
two P–Se bonds in each ligand moiety. The cobalt–se-
lenium bond lengths differ slightly and each ring con-
tains two unequal (one longer and one shorter)
cobalt–selenium bonds [Co–Se(1) 2.475(1) and Co–
31P NMR (CDCl3, rel. to 85% H3PO4): l 26.14 with
1
two P–Se satelites JP–Se=576 Hz.
IR (KBr pellets, cm−1): 3050 (wCH), 1170 (wasP2N),
1101, 757 (wsP2N), 693, 550 (wPSe), 519, 505. Mass spec.
(FAB+): m/z 869 [M+], 670, 460, 341.
,
Se(3) 2.439(1) A (‘long’) with Co–Se(2) 2.362(1) and
,
Co–Se(4) 2.383(1) A (‘short’)]. The cobalt(II) centre is
3.2. Preparation of Co[Ph2P(Se)–N–P(Se)Ph2]2 (6)
tetrahedrally coordinated with Se–Co–Se intra-ring
(endocyclic) bond angles slightly larger [e.g. (exocyclic)
bond angles [Se(1)–Co–Se(2) 113.38(3)° and Se(3)–
Co–Se(4) 114.06(3)°]. The opposite is observed in the
methyl thio analogue Co[Me2P(S)–N–P(S)Me2]2 with
exocyclic S–Co–S bond angles (111.7(1) and 114.3(1)°)
larger than endocyclic S–Co–S bond angles (109.6(1)
and 110.3(1)°) [16].
The structure of the cobalt(II) compound 6 can be
compared with that of a related bis(diselenodiimido-
triphosphinate) Co[Ph2P(Se)–N–P(Ph2)–N–P(Se)Ph2]2
(7) reported recently, which contains two eight-mem-
bered CoSe2P3N2 inorganic rings [43].
A solution of 0.300 g (0.516 mmol) K[Ph2P(Se)–N–
P(Se)Ph2] dissolved in 50 cm3 methanol was mixed with
stirring with a solution of 0.169 g (0.258 mmol)
Co(PPh3)2Cl2 dissolved in 25 cm3 chloroform. After
stirring for 30 min the precipitate was filtered off and
Table 3
Crystal data and structure determination of compounds 5 and 6
5
6
Crystal data
Empirical formula
C42H35CuNP3Se2 C48H40CoN2P4Se4
Formula weight
Crystal dimensions (mm)
Crystal system
868.08
0.50×0.20×0.10 0.65×0.40×0.20
triclinic triclinic
1143.47
(
(
Space group
P1
P1
Lattice parameters
,
a (A)
9.180(2)
12.056(2)
18.642(4)
79.24(3)
79.28(3)
73.34(3)
1922.5(7)
2
13.743(3)
13.830(3)
14.329(2)
82.623(14)
66.25(2)
66.98(2)
2292.9(8)
1
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
Cell volume (A )
In 7 the coordination geometry of cobalt(II) is also
distorted tetrahedral. In the ten-membered rings the
Se–Co–Se bond angles are larger (113.6(1) and
113.7(1)°) than the exocyclic bond angles (106.0(1) and
110.2(1)°). The Co–Se and P–N bond lengths in 6 and
7 are comparable.
Z
Dcalc (mg m−3
F(000)
)
1.500
872
1.656
1130
Absorption coefficient
2.617
3.725
(mm−1
)
Intensity measurements
Scan type
ꢀ–2q
ꢀ–2q
Index range
−11BhB10,
−14BkB14,
0BlB22
6433
−15BhB13,
−16BkB16,
0BlB17
8153
3. Experimental
No. reflections collected
No. independent reflections 6237 (Rint 0.1070) 7848 (Rint 0.0203)
Corrections none none
3.1. Preparation of Cu(PPh3)[Ph2P(Se)–N–P(Se)Ph2]
(5)
Structure solution and refinement
Structure solution
Refinement
No. of observations used
[I\2|(I)]
No. of variables
Final R indices
heavy atom (SHELX-86)
A solution of 0.300 g (0.516 mmol) K[Ph2P(Se)–N–
P(Se)Ph2] dissolved in 50 cm3 methanol was mixed with
stirring with a solution of 0.355 g (0.516 mmol)
Cu(PPh3)2NO3 dissolved in 25 cm3 chloroform. After
stirring for 30 min the precipitate was filtered off and
the filtrate was concentrated to give a solid. The
product was recrystallized from CH2Cl2.
Yield: 86% Cu(PPh3)[Ph2P(Se)–N–P(Se)Ph2]; m.p.
223°C.
Anal. Found: C, 57.9; H, 4.0; N, 1.6. Calc. for
C42H35CuNP3Se2: C, 58.1; H, 4.1; N, 1.6%.
full-matrix least-squares on F2
6237
7848
477
693
R1=0.0558
wR2=0.1634
R1=0.1042
wR2=0.1897
0.674
R1=0.0345
wR2=0.0887
R1=0.0644
wR2=0.0992
0.573
R all data
Max. peak in final differ-
−3
,
ence map (e A
)
Min. peak in final differ-
−1.318
−0.802
−3
,
ence map (e A
)

260
J. No6osad et al. / Inorganica Chimica Acta 290 (1999) 256–260
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the filtrate was concentrated to give a colourless solid,
which was recrystallized from CH2Cl2.
Yield: 81% Co[Ph2P(Se)–N–P(Se)Ph2]2.
Anal. Found: C, 54.0; H, 3.7; N, 2.6. Calc. for
C48H40CoN2P4Se4: C, 53.7; H, 3.7; N, 2.5%.
31P NMR (CDCl3, rel. to 85% H3PO4): l 27.7 (singlet).
IR (KBr pellets, cm−1): 3067 (wCH), 1479, 1436,1199
(wasP2N), 1106, 746 (wsP2N), 692, 545 (wPSe). Mass spec.
(FAB+): 1143 [M+], 542, 384, 307.
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4. Crystallographic data
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The single-crystal diffraction studies were performed
on a KUMA KM4 four-circle s-axis diffractometer.
Details about cell dimensions, data collection, structure
solving and refinement are shown in Table 3. The crystal
stability during the data collection was checked by
measuring three standard reflections (020, 002 and 210)
after every 300 measurements; no significant change of
their intensities was detected. The structures were solved
by the heavy-atom method, using the SHELX-86 program.
All atoms, except the hydrogens, were refined anisotrop-
ically by the full-matrix least-squares procedure (pro-
gram SHELX-93). The hydrogen atoms were positioned
from difference Fourier maps and refined isotropically.
Extinction and absorption corrections were not applied
because their application did not reduce the R values or
e.s.d.’s.
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Acknowledgements
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Dalton Trans. (1996) 391.
J. Novosad thanks Professor M. Watanabe, Faculty of
Engineering, Chubu University, Japan, for financial
support. J. Novesad, M. Necas and J. Marek wish to
express their gratitude to the Grant Agency of the Czech
Republic for Grants Nos. 203/97/0955, 203/98/0676 and
203/99/0067.
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