New manganese(II) complexes with tetraorganodichalcogenoimidodiphosphinato ligands. Crystal and molecular structure of monomeric Mn[(SPMe2)(SPPh2)N]2 and dimeric [Mn{(OPPh2){OP(OEt)2}N}2(H2O)]2

Article abstract of DOI:10.1016/j.poly.2008.06.023

New manganese(II) complexes of type Mn [(XPR₂) (YP R₂^′) N]₂ [X, Y = S, R = Me, R′ = Ph (1), X = S, Y = O, R = Ph, R′ = OEt (2)] and Mn[(OPPh₂){OP(OEt)₂}N]₂(H₂O) (3), were obtained by salt metathesis reactions between MnCl₂ · 4H₂O and the potassium salts of the appropriate tetraorganodichalcogenoimidodiphosphinic acids. The complexes were characterized by EPR and IR spectroscopy, as well as by mass spectrometry. The crystal and molecular structures for 1 and 3 were determined by single-crystal X-ray diffraction. Compound 1 crystallizes as monomeric species, with the manganese(II) atom in a tetrahedral environment, while for compound 3 a dimeric structure was found. Both tetraorganodichalcogenoimidodiphosphinato ligand units behave monometallic biconnective in 1, chelating the metal centre. In the dimeric species 3 the tetraphenylimidodiphosphinato ligand units behave different, two of them chelating the manganese atoms, as monometallic biconnective moieties, while the other two act bimetallic triconnective, bridging the two metal centres. The octahedral coordination geometry in 3 is completed by water molecules. The magnetic behaviour of 3 was investigated.

Full text of DOI:10.1016/j.poly.2008.06.023

Polyhedron 27 (2008) 2905–2910
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
New manganese(II) complexes with tetraorganodichalcogenoimidodiphosphinato
ligands. Crystal and molecular structure of monomeric Mn[(SPMe2)(SPPh2)N]2
and dimeric [Mn{(OPPh2){OP(OEt)2}N}2(H2O)]2
b
c
c
d
Ana Maria Preda a, Anca Silvestru a, , Sorin Farcas , Alina Bienko , Jerzy Mrozinski , Marius Andruh
*
a Faculty of Chemistry and Chemical Engineering, ‘‘Babes-Bolyai” University, Cluj-Napoca RO-400028, Romania
b National Institute for Research and Development of Isotopic and Molecular Technologies, P.O. Box 700, Cluj-Napoca RO-400293, Romania
c Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
d University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Str. Dumbrava Rosie nr. 23, 020464 Bucharest, Romania
a r t i c l e i n f o
a b s t r a c t
New manganese(II) complexes of type Mn½ðXPR2ÞðYPR0 ÞNꢀ [X, Y = S, R = Me, R0 = Ph (1), X = S, Y = O,
Article history:
2
2
R = Ph, R0 = OEt (2)] and Mn[(OPPh2){OP(OEt)2}N]2(H2O) (3), were obtained by salt metathesis reactions
between MnCl2 ꢁ 4H2O and the potassium salts of the appropriate tetraorganodichalcogenoimidodi-
phosphinic acids. The complexes were characterized by EPR and IR spectroscopy, as well as by mass
spectrometry. The crystal and molecular structures for 1 and 3 were determined by single-crystal
X-ray diffraction. Compound 1 crystallizes as monomeric species, with the manganese(II) atom in a
Received 30 April 2008
Accepted 23 June 2008
Available online 31 July 2008
Keywords:
Manganese(II) complexes
Molecular structure
Magnetic properties
tetrahedral environment, while for compound
3 a dimeric structure was found. Both tetra-
organodichalcogenoimidodiphosphinato ligand units behave monometallic biconnective in 1, chelating
the metal centre. In the dimeric species 3 the tetraphenylimidodiphosphinato ligand units behave dif-
ferent, two of them chelating the manganese atoms, as monometallic biconnective moieties, while the
other two act bimetallic triconnective, bridging the two metal centres. The octahedral coordination
geometry in 3 is completed by water molecules. The magnetic behaviour of 3 was investigated.
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
dithioato derivatives were also largely investigated. The manga-
nese(II) derivatives of dithioato or diselenoato ligands form spiro-
The coordination chemistry of the tetraorganodichalco-
genoimidodiphosphinato ligands was extensively investigated, in
connection both with Main Group or transition metals [1,2]. Com-
plexes of the first row divalent metals, i.e. Mn(II), Fe(II), Co(II),
Ni(II), with dithioimidodiphosphinato ligands exhibit mainly tetra-
hedral MS4 cores and the preference for a tetrahedral geometry
versus a square planar one was assumed based on a low to medium
ligand field strength of the [(SPR2)2N]ꢂ (R = Me, Ph) moiety [3].
The increased interest in manganese complexes is due mainly
to their biological or magnetic properties. It was noticed the pref-
erence of manganese(II) for the hard O- or N-donor atoms in bio-
logical systems, in contrast with S-donor atoms [4,5]. On the
other hand, magnetic materials are based on high-spin metal cen-
tres as manganese(II) or manganese(III) can generate with their
five and four, respectively, unpaired electrons [6]. Even if it was ob-
served that manganese containing proteins and magnetic materials
are mainly based on ligands with oxygen as donor atoms, the
bicyclic monomeric structures with a slightly distorted tetrahedral
MnX4 cores, as in the Mn½ðXPR2ÞðYPR0 ÞNꢀ species (X = Y = S,
2
2
R = R0 = Ph [7], X = Y = S, R = R0 = Pri, X = Y = S, R = Ph, R0 = Pri, X =
Y = Se, R = R0 = Ph [8]). For the monothio derivative Mn[(SPPh2)-
(OPPh2)N]2 a similar monomeric structure was found [9], while
for the dioxo analogue a dinuclear [Mn{(OPPh2)2N}2]2 species
was described [9,10]. For the manganese(I) compounds Mn(CO)4-
[(SPPh2)2N] [11] and Mn2(CO)6[(SPMe2)2N]2 [12], the tetra-
organodithioimidodiphosphinato ligand exhibits either
a
monometallic biconnective or a bimetallic triconnective pattern,
respectively, while for the manganese(III) derivative Mn-
[(OPPh2)2N]3 a monomeric structure with chelating ligands was
reported [13].
As part of our studies on the influence of the nature of the chal-
cogen atoms and the organic groups in the ligand unit on the struc-
ture and properties of manganese complexes, we report here on
the synthesis and spectroscopic characterization of some new
manganese(II) derivatives of type Mn½ðXPR2ÞðYPR0 ÞNꢀ [X, Y = S,
2
2
R = Me, R0 = Ph (1), X = S, Y = O, R = Ph, R0 = OEt (2)] and Mn[(OP-
Ph2){OP(OEt)2}N]2(H2O) (3), the molecular structures of 1 and 3,
as well as the magnetic behaviour of 3.
* Corresponding author. Tel.: +40 264 593833; fax: +40 264 590818.
E-mail address: ancas@chem.ubbcluj.ro (A. Silvestru).
0277-5387/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2008.06.023

2906
A.M. Preda et al. / Polyhedron 27 (2008) 2905–2910
Table 1
2. Experimental
Crystal data and structure refinement for Mn[(SPMe2)(SPPh2)N]2 (1) and Mn[(OP-
Ph2){OP(OEt)2}N]2(H2O) (3)
Potassium tetraorganodichalcogenoimidodiphosphinates were
prepared according to literature methods: K[(SPMe2)(SPPh2)N]
[14], K[(SPPh2){OP(OEt)2}N], K[(OPPh2){OP(OEt)2}N] [15]. Solvents
were purified by standard procedures and were freshly distilled
prior to use. IR spectra were recorded in the range 4000–
400 cmꢂ1 in KBr pellets on a Jasco FTIR-615 machine. Mass spectra
were recorded on a FINNIGAN MAT 8200 instrument (CI). EPR
spectra were recorded at 77 K and at room temperature on a Bru-
ker ESP 300 spectrometer operating in X-band, equipped with an
ER 035 M Bruker NMR gaussmeter and a HP 3530B Hewlett–Pack-
ard microwave frequency counter, and only at room temperature
on a X-band Radiopan SE/X 2543 Spectrometer, respectively. All
g factors were determined with 0.05 accuracy. Magnetic measure-
ments in the temperature range of 1.8–300 K were carried out on
powdered samples of complex 3, at a magnetic field of 0.5 T and
at 2 K in the range of 0–5 T, using a Quantum Design SQUID based
MPMSXL-5 type magnetometer. Corrections are based on subtract-
1
3
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C
28H32MnN2P4S4
C64H84Mn2N4O18P8
1554.99
703.62
297(2)
297(2)
0.71073
0.71073
monoclinic
P2(1)/c
triclinic
P2(1)/n
15.0259(11)
11.9642(9)
19.1422(14)
90
106.0830(10)
90
11.9760(9)
13.5226(10)
13.6310(11)
108.6870(10)
106.4710(10)
97.7490(10)
1942.4(3)
1
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3)
3306.6(4)
4
Z
Dcalc (g/cm3)
1.413
1.329
Absorption coefficient (mmꢂ1
F(000)
)
0.867
0.555
1452
810
Crystal size (mm)
h Range for data collections (°)
Reflections collected
Independent reflections (R(int))
Maximum and minimum
transmissions
0.29 ꢃ 0.23 ꢃ 0.21
2.03 to 25.00
23505
0.30 ꢃ 0.29 ꢃ 0.22
1.68 to 26.37
20991
ing the sample-holder signal and the contribution
v
D = 1181 ꢃ
10ꢂ6 cm3 molꢂ1 was estimated from the Pascal constants [16].
Elemental analyses were performed on a VarioEL analyzer.
5835 (0.0497)
0.8388 and 0.7871
7887 (0.0413)
0.8877 and 0.8513
Full-matrix least-squares on F2
2.1. Preparation of bis[P,P-dimethyl-P0,P0-diphenyl-dithioimido-
diphosphinato]manganese(II), Mn[(SPMe2)(SPPh2)N]2 (1)
Refinement method
Data/restraints/parameters
5835/0/356
1.154
7887/0/456
1.146
Goodness-of-fit on F2
Final R indicies [I > 2sigma(I)]
R1 = 0.0560,
wR2 = 0.1206
R1 = 0.0692,
wR2 = 0.1261
R1 = 0.0667,
wR2 = 0.1424
R1 = 0.0881,
wR2 = 0.1525
0.573 and ꢂ0.271
A
reaction mixture of K[(SPMe2)(SPPh2)N] (0.515 g, 1.420
R indicies (all data)
mmol) and MnCl2 ꢁ 4H2O (0.140 g, 0.707 mmol) in methanol
(50 ml) was stirred at room temperature for 24 h. The solvent
was completely removed in vacuum and the remaining solid was
extracted with toluene. The clear solution was concentrated in vac-
uum, yielding the title compound as a colourless crystalline prod-
uct. Yield: 0.261 g (52%), m.p. 119–120 °C. Anal. Calc. for
Largest difference in peak and hole 0.458 and ꢂ0.238
(eÅꢂ3
)
C
28H32MnN2P4S4: C, 47.79; H, 4.58; N, 3.98. Found: C, 47.68; H,
on cryoloops. The data were collected on a Bruker SMART APEX
CCD diffractometer using graphite-monochromated Mo K radia-
tion (k = 0.71073 Å). Data reduction was performed using the
SAINT-PLUS software and the data were corrected for absorption ef-
fects using the SADABS program [17]. The details of the crystal struc-
ture determination and refinement are given in Table 1.
4.52; N, 3.97%. IR (cmꢂ1): 1197s, br [
m
as(P2N)], 589s [ (PhPS)],
m
a
571s [m
(MePS)]. CIpos MS (m/z, %): 703 (42) [M+], 324 (100)
[{(SPMe2)(SPPh2)N}+]. CIneg MS (m/z, %): 703 (18) [Mꢂ], 324 (57)
[{(SPMe2)(SPPh2)N}ꢂ], 110 (100) [(SPMe2 + NH3)ꢂ].
Compounds 2 and 3 were similarly prepared:
Bis[P,P-diethoxy-P0,P0-diphenyl-P0-thioimidodiphosphinato] manga-
nese(II)], Mn[(SPPh2){OP(OEt)2}N]2 (2) from K[(SPPh2){OP(OEt)2}-
N] (0.720 g, 1.769 mmol) and MnCl2 ꢁ 4H2O (0.175 g, 0.883 mmol).
Yield: 0.315 g (45%), m.p. 95 °C. Anal. Calc. for C32H40MnN2O6S2P4:
C, 48.55; H, 5.09; N, 3.54. Found: C, 48.61; H, 5.05; N, 3.55%. IR
Cell refinement gave cell constants corresponding to monoclinic
(1) and triclinic (3) cells. The structures were solved by direct
methods [18] and refined using the SHELXTL [19] version of SHELX
-
97 [20]. Compound 3 is centrosymmetric with an inversion centre
in the middle of the Mn2O2 ring and thus half of the molecule is
generated by symmetry. The hydrogen atoms were refined with
a riding model and a mutual isotropic thermal parameter, except-
ing the hydrogen atoms from the water molecule in 3, which were
located on the difference map and refined at a O–H distance of
0.82(5) and 0.80(5) Å, respectively. C16 in 3 is disordered and
was refined over two positions with 49% and 51% occupancy. The
drawings were created with the DIAMOND program [21].
(cmꢂ1): 1265vs [
599s [
mas(P2N)], 1104s [m(PO)], 1033vs, br [m(POC)],
m
(PS)]. CIpos MS (m/z, %): 792 (100) [(M+H)+], 370 (92)
[{(SPPh2){OP(OEt)2}NH}+]. CIneg MS (m/z, %): 792 (12) [(M+H)ꢂ],
368 (100) [{(SPPh2){OP(OEt)2}N}ꢂ], 336 (26) [{(PPh2){OP(OEt)2}-
N}ꢂ].
Bis[P,P-diethoxy-P0,P0-diphenyl-imidodiphosphinato]manganese(II)
water solvate, Mn[(OPPh2){OP(OEt)2}N]2(H2O) (3) from K[(OP-
Ph2){OP(OEt)2}N] (0.151 g, 1.317 mmol) and MnCl2 ꢁ 4H2O
(0.130 g, 0.658 mmol). Yield: 0.36 g (70%), m.p. 100–102 °C. Anal.
Calc. for C32H42MnN2O9P4: C, 49.43; H, 5.44; N, 3.60. Found: C,
4. Results and discussion
49.75; H, 5.18; N, 3.65%. IR (cmꢂ1): 1244vs [
1143vs [ (PO)], 1067vs, 1041vs [
m
as(P2N)], 1157vs,
Manganese(II) complexes were obtained in moderate yields by
salt metathesis reactions between MnCl2 ꢁ 4H2O and the potassium
salt of the appropriate tetraorganodichalcogenoimidodiphosphinic
acid, in a 1:2 molar ratio.
m
m(POC)]. CIpos MS (m/z, %): 759
(52) [{Mn{(OPPh2){OP(OEt)2}N}2}+], 353 (100) [{(OPPh2){OP-
(OEt)2}NH}+]. CIneg MS (m/z, %): 760 (12) [{Mn{(OPPh2){OP-
(OEt)2}N}2+H}ꢂ], 352 (100) [{(OPPh2){OP(OEt)2}N}ꢂ], 336 (26)
[{(PPh2){OP(OEt)2}N}ꢂ].
MnCl2 ꢁ 4H2O þ 2K½ðXPR2ÞðYPR0 ÞNꢀ
2
! Mn½ðXPR2ÞðYPR0 ÞNꢀ ðnH2OÞ þ 2KCl þ ð4 ꢂ nÞH2O
2
2
X ¼ Y ¼ S; R ¼ Ph; R0 ¼ Me; n ¼ 0 ð1Þ
X ¼ S; Y ¼ O; R ¼ Ph; R0 ¼ OEt; n ¼ 0 ð2Þ
X ¼ Y ¼ O; R ¼ Ph; R0 ¼ OEt; n ¼ 1 ð3Þ
3. Crystal structure determination
Colourless block crystals of Mn[(SPMe2)(SPPh2)N]2 (1) and
Mn[(OPPh2){OP(OEt)2}N]2(H2O) (3) were attached with epoxy glue

A.M. Preda et al. / Polyhedron 27 (2008) 2905–2910
2907
The complexes were isolated as colourless (1 and 3) or slight
pink (2) solids and were characterized by mass spectrometry, IR
and EPR spectroscopy. For compounds 1 and 3 the crystal and
molecular structure was determined by single-crystal X-ray
diffraction.
In the CI mass spectra of the title compounds either the molec-
ular or the pseudo-molecular ions appear with high or medium
intensity, i.e. [Mn{(SPPh2)(SPMe2)N}2]+ (m/z 703, 42%), [Mn-
{(SPPh2){OP(OEt)2}N}2 + H]+ (m/z 792, 100%) and [Mn{(OPPh2){OP-
(OEt)2}N}2]+ (m/z 759, 52%) for 1, 2 and 3, respectively. For
derivative 3 the dimeric species or fragments with a higher mass
than that corresponding to the monomeric species were not
observed by chemical ionization.
The IR spectra are consistent with the coordination of the ligand
units in the deprotonated form, through both chalcogen atoms. The
strong absorption bands observed for the Mn(II) complexes in the
ranges 1250–1200, 1150–1110 and 600–550 cmꢂ1 were assigned
to mas(P2N), m(PO) and m(PS) stretching vibrations, respectively, in
comparison with the potassium salts used as starting materials
Fig. 1. EPR spectrum of 3 at 4.2 K.
[14,15].
The EPR spectra of the manganese(II) complexes are expected
to display a fine structure of five lines. However, only for com-
pounds 2 and 3 the fine structure was observed, while for the
derivative 1 only a broad band was found at room temperature
(g = 1.94), due probably to the paramagnetic ion clusters present
in this sample. The line width (390 Gs for 1, 502 Gs and 400 Gs
for the central line of 2 and 3, respectively) is consistent with a
strong crystal field around the paramagnetic ions. This behaviour
might be explained by the strong interaction with the crystal field
created by the ligands and the covalent interactions between the
Mn(II) ion and the ligands. The g values determined at room tem-
perature for the compounds 2 and 3 (2.01 and 2.03, respectively)
are also consistent with strong covalent interactions. Theoretical
calculations allowed us to determine the crystal field constant
D (431 Gs) for the species 3, which exhibits a fine structure. In
the case of this polycrystalline material we average the h angle
between the direction of the magnetic induction and the symme-
Table 2
Selected interatomic distances (Å) and angles (°) in Mn[(SPPh2)(SPMe2)N]2 (1)
Mn(1)–S(1)
Mn(1)–S(2)
S(1)–P(1)
S(2)–P(2)
N(1)–P(1)
N(1)–P(2)
2.4354(12)
2.4136(12)
2.0159(14)
2.0213(14)
1.595(3)
Mn(1)–S(3)
Mn(1)–S(4)
S(3)–P(3)
S(4)–P(4)
N(2)–P(3)
N(2)–P(4)
2.4438(12)
2.4001(12)
2.0177(14)
2.0155(15)
1.582(3)
1.591(3)
1.591(3)
S(1)–Mn(1)–S(2)
S(1)–Mn(1)–S(3)
S(1)–Mn(1)–S(4)
109.31(4)
113.90(4)
106.33(4)
S(3)–Mn(1)–S(4)
S(2)–Mn(1)–S(4)
S(2)–Mn(1)–S(3)
111.02(4)
108.11(4)
108.02(4)
Mn(1)–S(1)–P(1)
Mn(1)–S(2)–P(2)
N(1)–P(1)–S(1)
N(1)–P(2)–S(2)
P(1)–N(1)–P(2)
105.10(5)
99.59(5)
118.68(12)
115.90(12)
129.5(2)
Mn(1)–S(3)–P(3)
Mn(1)–S(4)–P(4)
N(2)–P(3)–S(3)
N(2)–P(4)–S(4)
P(3)–N(2)–P(4)
104.70(5)
99.63(5)
118.53(12)
118.27(13)
134.7(2)
try axes of the magnetic centre from 0 to
tonian [22].
p/2 in the Spin Hamil-
The EPR spectrum of the complex 3 at 4.2 K exhibits a single
broad line with g = 1.98, Hpp = 565 Gs ( Hpp = peak to peak line-
D
D
width) and shows a partial resolved hyperfine structure due to
the interaction between the transition inside Krammer’s doublet
( 1/2) and the 55Mn(II) nuclear spin I = 5/2, of a value about
95 Gs (Fig. 1).
4.1. Crystal and molecular structure of Mn[(SPMe2)(SPPh2)N]2 (1)
The molecular structure of 1 was determined by single-crystal
X-ray diffraction. Important bond distances and angles are listed
in Table 2.
The crystal of 1 consists of distinct monomeric units separated
by normal van der Waals distances. An ORTEP-like diagram with
the atom numbering scheme is given in Fig. 2.
The dithioato ligand units behave monometallic biconnective,
resulting in a spiro-bicyclic system with a slightly distorted tetra-
hedral MnS4 core (S–Mn–S bond angles in the range 106.3–
113.9°). One of the endocyclic angles is larger [S(3)–Mn(1)–S(4)
111.02(4)°], while the other one [S(1)–Mn(1)–S(2) 109.32(4)°] is
close to the tetrahedral value of 109.5°. The dihedral angle be-
tween the S(1)/Mn(1)/S(2) and S(3)/Mn(1)/S(4) planes is
87.46(4)°, larger than those observed for Mn[(SPPh2)2N]2 (86.8°)
[7] and Mn½ðSPPri ÞðSPPh2ÞNꢀ [78.99(3)°] [8], and slightly smaller
2
2
than that one found for Mn½ðSPPri2Þ2Nꢀ2 [88.12(1)°] [8]. The Mn–S
bond distances [av. 2.423(1) Å] are similar to those found in
Mn[(SPPh2)2N]2 [av. 2.443(12) Å] [7].
Fig. 2. ORTEP plot at 40% probability and atom numbering scheme for 1. For clarity,
the hydrogen atoms are omitted.

2908
A.M. Preda et al. / Polyhedron 27 (2008) 2905–2910
The two six-membered MnS2P2N chelate rings are not planar
2.071(1) Å, P@N 1.562(2) Å, PAN 1.610(2) Å. The P–N–P angles
are different in the two ligand moieties [P(1)–N(1)–P(2) 129.5(2)
and P(3)–N(2)–P(4) 134.7(2)°], both being considerably larger in
comparison with the free acid [P–N–P 126.1(4)°] [24], and thus
suitable to accommodate around the metal centre.
and display twisted chair conformations with the Mn(1)/N(1) and
Mn(1)/N(2) atoms, respectively, in apices. In contrast, twisted boat
conformations were observed for other reported dithioato deriva-
tives, i.e. Mn[(SPPh2)2N]2 [7] and Mn½ðSPPri2Þ2Nꢀ2 [8] (with phos-
phorus and sulfur atoms in the apices) or Mn½ðSPPri ÞðSPPh2ÞNꢀ
2
2
[8] (with manganese and nitrogen atoms in apices), respectively.
4.2. Crystal and molecular structure of Mn[(OPPh2){OP(OEt)2}N]2-
The phosphorus–sulfur [range of 2.0155(15)–2.0213(14) Å] and
phosphorus–nitrogen [range of 1.582(3)–1.595(3) Å] distances,
respectively, are intermediate between the single and the double
bonds [cf. Ph2P(@S)–N@P(–SMe)Ph2 [23]: P@S 1.954(1) Å, P–S
(H2O) (3)
Selected bond distances and angles for 3 are listed in Table 3
and the ORTEP-like diagram with the atom numbering scheme is
given in Fig. 3.
The crystal contains discrete dimer associations in which the
metal centres are bridged by the oxygen atoms of the OP(OEt)2
groups from two ligand units acting as bimetallic triconnective
moieties, thus resulting in a fused tricyclic Mn2O4P4N2 system.
The other two ligands chelate each a metal atom, resulting in an
overall structure which resembles that found in the dimeric
[Mn{(OPPh2)2N}2]2 [9]. However some significant differences have
to be noted. The central four-membered Mn2O2 ring in the dimer of
the title compound 3 is planar, while it is slightly folded in the re-
lated [Mn{(OPPh2)2N}2]2. This behaviour is consistent with a larger
nonbonding MnꢁꢁꢁMn distance in 3 than in [Mn{(OPPh2)2N}2]2
[3.4073(6) Å versus 3.378(3) Å].
The overall conformation of the [Mn{(OPPh2)2N}2]2 dimer might
be described as cis, i.e. with the six-membered MnO2P2N rings
formed by ligands of the same type placed on the same side of
the four-membered Mn2O2 ring (Fig. 4 a) [9]. By contrast, the fused
tricyclic Mn2O4P4N2 system in the dimer of 3 is considerably flat-
tened, with equivalent atoms of the six-membered MnO2P2N rings
deviated on opposite sides of the central planar Mn2O2 core [devi-
ations from Mn2O2 plane: O(3) 0.042, P(3) 0.226, N(2) ꢂ0.160 Å,
and P(4) 0.419 Å, respectively]. The chelate MnO2P2N rings are
placed on opposite sides of this flattened tricyclic system and the
overall conformation in the dimer of 3 might be described as trans
(Fig. 4 b).
Table 3
Selected interatomic distances (Å) and angles (°) in Mn[(OPPh2){OP(OEt)2}N]2(H2O)
(3)a
Mn(1)–O(1)
Mn(1)–O(2)
2.088(2)
2.168(2)
Mn(1)–O(3)
Mn(1)–O(4)
Mn(1)–O(4a)
2.102(2)
2.237(2)
2.247(2)
Mn(1)–O(9)
2.271(3)
O(1)–P(1)
O(2)–P(2)
O(5)–P(2)
O(6)–P(2)
N(1)–P(1)
N(1)–P(2)
1.508(2)
1.496(2)
1.572(3)
1.573(3)
1.595(3)
1.553(3)
O(3)–P(3)
O(4)–P(4)
O(7)–P(5)
O(8)–P(5)
N(2)–P(3)
N(2)–P(4)
1.500(3)
1.503(2)
1.556(3)
1.577(3)
1.587(3)
1.567(3)
O(1)–Mn(1)–O(4)
O(2)–Mn(1)–O(9)
174.98(9)
163.68(10)
O(3)–Mn(1)–O(4a)
169.96(9)
O(1)–Mn(1)–O(2)
O(1)–Mn(1)–O(3)
O(1)–Mn(1)–O(9)
O(1)–Mn(1)–O(4a)
93.52(9)
92.32(9)
93.73(11)
97.51(9)
O(4)–Mn(1)–O(2)
O(4)–Mn(1)–O(3)
O(4)–Mn(1)–O(9)
O(4)–Mn(1)–O(4a)
91.15(9)
88.92(9)
81.29(11)
81.11(9)
O(2)–Mn(1)–O(3)
O(3)–Mn(1)–O(9)
97.16(10)
97.13(11)
O(9)–Mn(1)–O(4a)
O(4a)–Mn(1)–O(2)
80.26(10)
84.31(9)
Mn(1)–O(4)–Mn(1a)
98.89(9)
Mn(1a)–O(4)–P(4)
Mn(1)–O(2)–P(2)
125.07(13)
127.83(13)
Mn(1)–O(3)–P(3)
Mn(1)–O(4)–P(4)
Mn(1a)–O(4)–P(4)
131.25(15)
126.95(14)
130.33(13)
The oxygen atom from a water molecule completes a distorted
octahedral coordination geometry around the manganese atoms in
the dimer of 3, in contrast with the trigonal bipyramidal geometry
observed for the related [Mn{(OPPh2)2N}2]2 analogue [9]. More-
over, the water molecules are involved in hydrogen bonding with
O(1)–P(1)–N(1)
O(2)–P(2)–N(1)
P(1)–N(1)–P(2)
119.60(15)
117.87(15)
130.2(2)
O(3)–P(3)–N(2)
O(4)–P(4)–N(2)
P(3)–N(2)–P(4)
118.24(15)
117.29(15)
128.2(2)
a
Symmetry equivalent positions (ꢂx, ꢂy, ꢂz) are given by ‘‘a”.
Fig. 3. ORTEP plot of the dimer unit in the crystal of 3. The atoms are drawn with 30% probability ellipsoids [symmetry equivalent atoms (ꢂx, ꢂy, ꢂz) are given by ‘‘a”]. For
clarity, the hydrogen atoms, other than water hydrogens, are omitted.

A.M. Preda et al. / Polyhedron 27 (2008) 2905–2910
2909
Fig. 4. Dimer cores in (a) [Mn{(OPPh2)2N}2]2 [9], and (b) title compound 3. For clarity, the hydrogen atoms, other than water hydrogens, and the carbon atoms are omitted.
the oxygen atom connected to the metal centre from the chelating
ligand [H(1A)ꢁꢁꢁO(2a) 2.05 Å] and one oxygen atom of an ethoxy
group from the bridging ligand [H(1B)ꢁꢁꢁO(8a) 2.30 Å], respectively
(Fig. 3).
The monometallic biconnective MnO2P2N rings show distorted
chair conformations with nitrogen and manganese atoms in apices,
while for the bridging ligands the corresponding MnO2P2N rings
exhibit distorted boat conformations, with bridging O(4) and P(3)
atoms in apices.
The Mn–O distances in the Mn–O–Mn bridge are equivalent
[Mn(1)–O(4) 2.237(2), Mn(1)–O(4a) 2.247(2) Å] and considerably
longer than the Mn(1)–O(3) bond distance [2.102(2) Å] in the same
ligand unit. Even longer is the Mn–Owater bond distance [Mn(1)–
O(9) 2.271(3) Å]. For the monometallic biconnective ligand moiety
the Mn–O bonds are also not equivalent [Mn(1)–O(1) 2.088(2),
Mn(1)–O(2) 2.168(2) Å], a behaviour which contrasts with that
observed for the ligand moieties exhibiting a similar, but symmet-
ric, coordination pattern in the related [Mn{(OPPh2)2N}2]2 dimer
[9].
The phosphorus–nitrogen [range 1.553(3)–1.595(3) Å] and
phosphorus–oxygen distances [range 1.496(2)–1.508(2) Å], respec-
tively, are of a magnitude intermediate between a single and a
Fig. 5. Plot of
vMnT vs. T in the temperature range 10–300 K for 3. The solid line
represents the best fit to the experimental data with the parameters reported in the
text (inset: temperature dependence of vꢂM1n).
double bond, thus suggesting some delocalization of the
p elec-
trons on the OPNPO system in all four ligand units (cf. [(Me3-
Si)2N–P(@NtBu)S]2 [25]: P@N 1.529(2) Å, P–N 1.662(2) Å;
Ph2P(O)OH [26]: P@O 1.486(6) Å, P–O 1.526(6) Å).
Ng2b2
55 þ 30e5x þ 14e9x þ 5e12x þ e14x
ꢂ2J
vMn
¼
;
x ¼
kT 11 þ 9e5x þ 7e9x þ 5e12x þ 3e14x þ e15x
kT
Additional interdimer interactions have been introduced in the
frame of the mean-field approximation [28]:
4.3. Magnetic properties
vMn
The magnetic behaviour of complex 3 in the form of
sus T curve is shown in Fig. 5 ( Mn is the molar magnetic suscepti-
bility per Mn(II) ion). The value of MnT product at room
temperature is 4.87 cm3 molꢂ1
eff. = 6.24 B.M.), which is
slightly larger than that calculated for S = 5/2 with g = 2
(4.375 cm3 molꢂ1 K,
eff. = 5.92 B.M.). Upon lowering the tempera-
ture, MnT decreases gradually and reaches value of
0.61 cm3 molꢂ1 K at 1.8 K.
The temperature variation of vꢂM1n, from room temperature down
v
MnT ver-
corr
Mn
v
¼
2J0
v
1 ꢂ
vMn
Nb2g2
v
zJ0 is the intermolecular exchange parameter and z is the number of
the nearest neighbours. Least-square fit to the experimental data
gives J = ꢂ3.5 cmꢂ1, zJ0 = ꢂ1.0 cmꢂ1, g = 1.99.
K
(l
l
v
a
5. Supplementary data
to 10 K, follows a Curie–Weiss law (
v
M = C/(T ꢂ
H
), with C =
CCDC 656244 and 656245 contain the supplementary crystal-
lographic data for 1 and 3. These data can be obtained free of
charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or
from the Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
5.36 cm3 molꢂ1 K and
H
= ꢂ28.9 K. Below 10 K, the slope of
v
ꢂ1
Mn
changes (inset to Fig. 5). The magnetic susceptibility can be ana-
lyzed using the isotropic spin Hamiltonian: H = ꢂ2JS1S2. The tem-
perature dependence of the magnetic susceptibility is given by
the equation [27]:

2910
A.M. Preda et al. / Polyhedron 27 (2008) 2905–2910
[11] N. Zuniga-Villarreal, C. Silvestru, M. Reyes-Lezama, S. Hernandez-Ortega,
Acknowledgements
C. Alvarez Toledano, J. Organomet. Chem. 496 (1995) 169.
[12] N. Zuniga-Villarreal, M. Reyes-Lezama, G. Espinosa, J. Organomet. Chem. 626
(2001) 113.
[13] N. Zuniga-Villarreal, M. Reyes-Lezama, S. Hernandez-Ortega, C. Silvestru,
Polyhedron 17 (1998) 2679.
This work was supported by the Romanian Ministry of Educa-
tion and Research (Grant CERES 4-62/2004) and the Polish Ministry
of Science and Higher Education (Grant No. 1T09A 12430).
[14] R. Roesler, C. Silvestru, G. Espinosa-Perez, I. Haiduc, R. Cea-Olivares, Inorg.
Chim. Acta 241 (1996) 47.
[15] G. Balazs, J.E. Drake, C. Silvestru, I. Haiduc, Inorg. Chim. Acta 287 (1999) 61.
[16] E. König, Magnetic Properties of Coordination and Organometallic Transition
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[17] SAINT-PLUS 2001, Bruker AXS Inc., Madison, WI, 2001.
[18] G.M. Sheldrick, Acta Crystallogr. Sect. A 46 (1990) 467.
[19] SHELXTL, Bruker AXS Inc., Madison, WI, 2000.
[20] G.M. Sheldrik, SHELX-97, Universität Göttingen, Germany, 1997.
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