Transformations of high spin MnII and FeII polymeric pivalates in reactions with pivalic acid and o-phenylenediamines

Article abstract of DOI:10.1007/s11172-006-0337-5

The thermolysis and reactions of the polymeric high spin Mn^II and Fe^II complexes [Mn(μ-OOCBu^t)₂(HOEt)] _n (1) and [Fe(μ-OOCBu^t)₂]_n (3) with pivalic acid and o-phenylenediamines 1,2-(NH₂)₂C ₆H₂R₂ (R = H or Me) were studied. The synthesis of compound 1 performed with a deficiency of pivalate anions affords the antiferromagnetic chloropivalate polymer { (MeCN)(HOOCBu^t)(H ₂O)Mn₅Cl(OH)(OOCBu^t)₈?MeCN} _n. The reaction of 1 with an excess of pivalic acid produces the antiferromagnetic polymer [Mn₄(OOCBu^t) ₈(HOOCBu^t)₂]_n. The analogous reaction of pivalic acid with polymer 3 gives the mononuclear complex Fe(η ¹-OOCBu^t)₂(η¹-HOOCBu ^t)₄ containing the high spin iron(II) atom as the major product. Study of the reactions of 3 with a deficiency (<1: 1) and an excess (>1: 1) of diamines demonstrated that the polymer {[(η²- (NH₂)₂C₆H₄)₂Fe(μ- OOCBu^t)₂][Fe₂(μ-OOCBu^t) ₄] ? ? 2MeCN}_n is generated as the major product in the former case, whereas the mononuclear complexes Fe(η¹- OOCBu^t)₂[η¹-(NH₂) ₂C₆H₄]₄ and Fe(η¹- OOCBu^t)₂[η²-(NH₂) ₂C₆H₂Me₂][η¹-(NH ₂)₂C₆H₂Me₂]₂ are predominantly obtained in the latter case. Springer Science+Business Media, Inc. 2006.

Full text of DOI:10.1007/s11172-006-0337-5

Russian Chemical Bulletin, International Edition, Vol. 55, No. 5, pp. 806—820, May, 2006
806
Transformations of high spin MnII and FeII polymeric pivalates
in reactions with pivalic acid and oꢀphenylenediamines
M. A. Kiskin,aꢀ G. G. Aleksandrov,a Zh. V. Dobrokhotova,a V. M. Novotortsev,a
Yu. G. Shvedenkov,b and I. L. Eremenkoa
aN. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
31 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (495) 955 4835. Eꢀmail: ilerem@igic.ras.ru
bA. V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences,
3 prosp. Akad. Lavrent´eva, 630090 Novosibirsk, Russian Federation.
Fax: +7 (383) 330 9489
The thermolysis and reactions of the polymeric high spin MnII and FeII complexes
[Mn(µꢀOOCBut)2(HOEt)]n (1) and [Fe(µꢀOOCBut)2]n (3) with pivalic acid and oꢀphenylenediꢀ
amines 1,2ꢀ(NH2)2C6H2R2 (R = H or Me) were studied. The synthesis of compound 1 perꢀ
formed with a deficiency of pivalate anions affords the antiferromagnetic chloropivalate polyꢀ
mer {(MeCN)(HOOCBut)(H2O)Mn5Cl(OH)(OOCBut)8•MeCN}n. The reaction of 1 with an
excess of pivalic acid produces the antiferromagnetic polymer [Mn4(OOCBut)8(HOOCBut)2]n.
The analogous reaction of pivalic acid with polymer 3 gives the mononuclear complex
1
1
Fe(η ꢀOOCBut)2(η ꢀHOOCBut)4 containing the high spin iron(II) atom as the major product.
Study of the reactions of 3 with a deficiency (<1 : 1) and an excess (>1 : 1) of diamines
2
demonstrated that the polymer {[(η ꢀ(NH2)2C6H4)2Fe(µꢀOOCBut)2][Fe2(µꢀOOCBut)4]•
•2MeCN}n is generated as the major product in the former case, whereas the mononuclear
1
1
1
2
1
complexes Fe(η ꢀOOCBut)2[η ꢀ(NH2)2C6H4]4 and Fe(η ꢀOOCBut)2[η ꢀ(NH2)2C6H2Me2][η ꢀ
(NH2)2C6H2Me2]2 are predominantly obtained in the latter case.
Key words: iron(II) complexes, polynuclear manganese(II) complexes, carboxylate ligands,
synthesis, Xꢀray diffraction study, magnetic properties, thermal decomposition.
In the synthesis of molecular magnets, it is important
particular, with pivalic acid and oꢀphenylenediamines
1,2ꢀ(NH2)2C6H2R2 (R = H or Me). We also studied the
thermolysis products of these polymers. These investigaꢀ
tions are also of interest because the starting polymeric
"spin materials" differ in the magnetic characteristics. Iron
derivatives 2 and 3 exhibit the ferromagnetic properties
unlike antiferromagnetic manganese polymer 1. Moreꢀ
over, magnetic ordering was observed for complex 3
at 3.8 K (Fig. 1).
to correctly choose the starting compound containing high
spin transition metal ions. Coordination polymers are conꢀ
venient compounds because their directed chemical degꢀ
radation allows one to form molecules with desired strucꢀ
tures and, as a result, with a particular spin density distriꢀ
bution.1—5 The number of metal centers and the mutual
arrangement of magnetic ions in the newly formed molꢀ
ecules are determined by the electronic nature and strucꢀ
tural characteristics of the donor organic ligands used as
"slicers" for such nꢀdimensional systems.
Results and Discussion
Recently, we have found that the polymeric carboxyꢀ
late complexes [M(µꢀOOCBut)2(HOEt)]n (1 and 2) (M =
MnII (1) or FeII (2)) and [Fe(µꢀOOCBut)2]n (3) are transꢀ
formed in nearly 100% yield into dinuclear antiferromagꢀ
nets L2M2(µꢀOOCBut)4 (M = Mn, L is 2,6ꢀdiaminoꢀ
pyridine; M = Fe, L is 2,6ꢀlutidine or 2,6ꢀdiaminoꢀ
pyridine)6—8 with high spin MnII (S = 5/2)9 and FeII
(S = 2)10 atoms by the reactions with αꢀsubstituted pyꢀ
ridines. In the present study, we examined the reactions
of MnII and FeII polymeric pivalates with Oꢀ and Nꢀdonor
organic molecules containing two donor centers, in
Earlier,6 we have demonstrated that the coordination
polymer [Mn(µꢀOOCBut)2(HOEt)]n (1) readily soluble
in organic solvents can easily be prepared in high yield
by the reaction of manganese(II) salts with potassium
pivalate (KOOCBut) in ethanol. However, it appeared
that it is important to use a special reagent ratio in the
synthesis of 1. When pivalate anions are in deficiency, the
reaction of aqueous manganese chloride with KOOCBut
(reagent ratio [Mn] : [K] ≈ 1.5 : 2) produces a polyꢀ
meric complex containing the MnCl fragments incorꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 779—792, May, 2006.
1066ꢀ5285/06/5505ꢀ0806 © 2006 Springer Science+Business Media, Inc.

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
807
µ
eff/µ
Scheme 1
B
σ/Gs cm3 mol–1
10
10
9
a
b
8
6
4
TC = 3.8 K
8
7
2
4
6
T/K
6
5
50
100
150
200
250
T/K
Fig. 1. Plots of µeff(T ) (a) and magnetization σ(T ) measured in
a small magnetic field (b) for complex 3.
porated into the polymer system of manganese
pivalate. Recrystallization of this product from acetoꢀ
nitrile
afforded
the
polymeric
compound
{(MeCN)(HOOCBut)(H2O)Mn5Cl(OH)(OOCBut)8•
•MeCN}n (4) in 46% yield (Scheme 1).
Reagents and conditions: a. 1.5 < x : y < 2, EtOH, Ar, 87 °C;
b. MeCN, Ar, 81 °C.
Xꢀray diffraction study demonstrated that polymer 4 is
a complex chain consisting of the pentanuclear fragments
(MeCN)(HOOCBut)(H2O)Mn5Cl(OH)(OOCBut)8.
Each fragment contains the triangle of manganese atoms
centered by the bridging hydroxy group, Mn3(µ3ꢀOH), as
the central unit (Mn—O, 2.103(8)—2.150(8) Å). Two of
three Mn atoms of this triangle (Mn...Mn, 3.505(3) Å)
are linked together by two O,Oꢀbridging carboxylate
groups (Mn—O, 2.094(8)—2.213(9) Å), whereas the
third Mn atom is linked to the other two Mn atoms by one
O,Oꢀcarboxylate bridge (Mn...Mn, 3.626(3) Å; Mn—O,
2.099(9), 2.326(9) Å) and one Oꢀcarboxylate bridge
(Mn...Mn, 3.370(3) Å; Mn—O, 2.142(9), 2.323(8) Å)
(Fig. 2).
O(8)
C(16)
O(13)
C(31)
O(14)
C(26)
O(11)
O(7)
C(47A)
O(1WA)
O(18C)
O(12)
Mn(4)
N(1A)
Mn(2)
C(11A)
O(15)
O(6A)
O(9A)
Cl(1A)
O(5A)
C(36)
O(1)
O(1M)
O(2)
Mn(3)
O(3)
O(18A)
C(41A)
C(21A)
C(1)
C(6)
Mn(1)
Mn(5A)
O(4A)
Mn(1A)
O(16)
O(10A)
C(41)
O(17)
O(10)
Mn(3A)
O(2A)
O(16A)
C(36A)
O(17A)
O(4)
O(18)
Mn(5)
C(1A)
C(21)
O(15A)
O(3A)
O(1MA)
O(1A)
O(5)
Mn(4A)
Cl(1)
O(9)
C(11)
N(1)
Mn(2A)
O(11A)
O(6)
O(12A)
O(14A)
C(31A)
O(18B)
C(26A)
O(1W)
O(7A)
C(16A)
C(47)
O(13A)
O(8A)
Fig. 2. Fragment of the polymer chain of 4 (tertꢀbutyl substituents at the carboxylate groups are omitted).

808
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
Two additional manganese atoms are bound
magnetic susceptibility follows the Curie—Weiss law with
to the metal atoms of the triangle (Mn...Mn,
3.542(3)—3.607(3) Å). One of these atoms is coordinated
to two chlorine atoms serving as bridges between the
pentanuclear fragments of the metal chain (Mn—Cl,
2.427(4) and 2.581(4) Å) and three oxygen atoms of
the bridging pivalate groups having different dentation
(Mn—O, 2.056(10), 2.131(8), and 2.209(9) Å). Another
peripheral manganese atom is linked to the triangle
by two bridging carboxylate groups (Mn—O,
2.085(9)—2.142(9) Å) and is coordinated by the water
molecule (Mn—O, 2.223(10) Å) and the chelating carꢀ
boxylate group (Mn—O, 2.263(7) and 2.356(9) Å). The
latter, in turn, also serves as a bridge between the adjacent
pentanuclear fragments of the metal chain (Mn—O,
2.114(9) Å). The magnetic properties of coordination
compound 4 are analogous to those of polymeric pivalate 1
studied earlier. A decrease in the temperature to 2 K leads
to a decrease in µeff of complex 4 to 3.29 µB (Fig. 3),
which is evidence for the dominating antiferromagꢀ
netic interactions in this compounds. The efficiency of
interactions is rather high because µeff is 12.57 µB already
at 300 K. This value is similar to the pureꢀspin value of
13.2 µB for five weakly interacting MnII ions with the spin
S = 5/2. In the temperature range of 100—300 K, the
the following parameters: C = 23.2 0.2 K cm3 mol–1
θ = –52.3 0.2 K.
,
Formally, polymers 1 and 4 are similar in the magꢀ
netic properties, which makes it difficult to estimate the
purity of the starting compounds used in further syntheses
by magnetic methods. However, pure polymer 1 (purity
was confirmed by elemental analysis for chlorine and specꢀ
troscopic characteristics) can be prepared by this reaction
with the use of the pivalate anion : manganese atom ratio
of 2 : 1.
The reaction of polymer 1 with an excess of pivalic acid
in hexane or acetonitrile (t > 68 °C) leads to removal of
the coordinated ethanol molecules giving rise to virtually
the only product, viz., the [Mn4(OOCBut)8(HOOCBut)2]n
polymer (5) (Scheme 2). The structure of compound 5
was established by Xꢀray diffraction4 (Table 1).
The magnetic behavior of polymer 5 is qualitatively
analogous to the aboveꢀdescribed behavior of complex 4
(see Fig. 3). The magnetic moment µeff decreases from
11.19 to 2.13 µB in the temperature range of 300—2 K due
to antiferromagnetic exchange interactions. At high temꢀ
peratures, the curve 1/χ(T ) for 5 is described by the
Curie—Weiss equation with the following parameters:
C = 17.4 0.1 K cm3 mol–1, θ = –33.3 0.3 K.
µ
eff/µ
µeff/µ
B
B
12
10
8
12
9
a
b
6
6
4
2
3
50
100
150
200
250
T/K
50
100
150
200
250
T/K
χ
–1/mol cm–3
20
χ
–1/mol cm–3
20
c
d
15
10
5
15
10
5
50
100
150
200
250
T/K
50
100
150
200
250
T/K
Fig. 3. Plots of µeff(T ) (a, b) and 1/χ(T ) (c, d) for polymers 4 (a, c) and 5 (b, d).

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
809
Scheme 2
Reagents and conditions: HOOCBut, MeCN, or hexane, Ar.
Unlike the reaction of the manganeseꢀcontaining
pivalate polymer, the analogous reaction of polymeric
iron(II) pivalate [Fe(µꢀOOCBut)2]n (3) with pivalic acid
in hexane (68 °C, [Fe] : HOOCBut = 1 : 4) affords the
the hydroxy fragments of coordinated carboxylic acids are
involved in intramolecular hydrogen bonding with the
terminal (O—H...O, 1.69 Å) or coordinated (O—H...O
1.79—1.80 Å) oxygen atoms of the pivalate anions
(see Fig. 4).
The magnetic moment µeff of mononuclear complex 6
changes weakly in the temperature range of 300—40 K
(5.14—4.93 µB) (Fig. 5). At room temperature, the magꢀ
netic moment µeff is characteristic of the high spin
FeII ion. Only after a decrease in the temperature to 2 K,
mononuclear
compound
Fe(η1ꢀOOCBut)2(η1ꢀ
HOOCBut)4 (6) (Scheme 3).
Complex 6 can also be prepared starting from the
tetranuclear complex Fe4(µ3ꢀOH)2(µꢀOOCBut)4(η2ꢀ
OOCBut)2(η1ꢀEtOH)6 (7)7 (hexane, 68 °C, [Fe] :
HOOCBut = 1 : 5) (see Scheme 3).
Xꢀray diffraction study demonstrated that the metal
µeff monotonically decreases to 3.38 µB due to the appearꢀ
atom in mononuclear complex
6
is coordinated
ance of weak intermolecular antiferromagnetic interꢀ
by six oxygen atoms of two pivalate groups and four
pivalic acid molecules (Fe—O, 2.075(2)—2.166(2) Å;
C—O(OOCR), 1.242(4)—1.277(4) Å; C—O(HOOCR),
1.214(4)—1.314(4) Å) (Fig. 4). The hydrogen atoms of
actions.
The tendency of MnII pivalate 1 to retain the polymer
structure in spite of an excess of pivalic acid in the reacꢀ
tion system is an important difference in the chemical
Table 1. Crystallographic parameters for complexes 4—6 and 11—13
Parameter
4
5
6
11
12
13
Molecular
formula
Space group
a/Å
b/Å
c/Å
C49H90ClMn5N2O20 C50H90Mn4O20
C30H58FeO12 C23H38Fe1.5N3O6 C34H50FeN8O4 C34H54FeN6O4
P21/n
14.653(7)
21.236(11)
21.130(11)
90
91.639(18)
90
6572(6)
4
P–1
P21/c
17.308(5)
10.579(3)
21.370(7)
90
105.571(9)
90
3769(2)
4
C2/c
21.594(6)
11.131(3)
22.158(5)
90
92.743(7)
90
5320(2)
8
P21/c
8.894(2)
17.931(5)
22.772(5)
90
99.455(6)
90
3582.2(14)
4
P–1
11.7317(7)
12.4788(7)
22.0506(13)
92.6120(10)
95.7350(10)
98.7340(10)
3168.7(3)
2
12.932(6)
16.430(8)
19.325(8)
77.479(7)
73.210(13)
70.719(9)
3677(3)
4
α/deg
β/deg
γ/deg
V/Å3
Z
ρ
calc/g cm–3
1.352
1.290
1.175
1.339
1.281
1.204
µ/cm–1
10.40
8.43
4.52
8.69
4.69
4.53
Number of
measured
reflections
Number of
reflections
with I > 4.0σ
R1
22995
19606
21823
10067
21517
24425
9928
14311
7846
4559
8175
15273
0.0894
0.1673
0.0526
0.1308
0.0744
0.1894
0.0692
0.1501
0.0794
0.1956
0.0593
0.1482
wR2

810
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
Scheme 3
Reagents and conditions: a. HOOCBut ([Fe] : L = 1 : 4), hexane, 68 °C, Ar; b. HOOCBut ([Fe] : L = 1 : 5), hexane, 68 °C, Ar.
properties of the manganese and iron polymers. Unlike
compound 1, iron(II) polymer 3 is readily decomposed in
the presence of the excess acid to give high spin monoꢀ
nuclear complex 6 containing 18ꢀelectron octahedral
FeII ions in spite of the formal electron deficiency
(14ꢀelectron iron atoms are in a tetrahedral environment)
and coordination deficiency of the metal centers. Apparꢀ
ently, this signifies that the strength of binding of the
metal atoms with the bridging pivalate groups in the manꢀ
ganese polymers differs from that in the iron polymers in
spite of the relative similarity of the structural fragments
of these polymers, which are chains consisting of the
metal atoms linked to each other by pairs of pivalate
bridges (Fig. 6).
To qualitatively estimate the stability of the starting
polymers, we studied thermolysis of these compounds in
the solid state. We found that decomposition of polymeric
manganese pivalate 1 starts already at 60 °C. In the temꢀ
perature range of 60—100 °C, the weight loss of 14.5 1.5%
is observed (which corresponds to removal of the coordiꢀ
nated ethanol molecule and the possible formation of the
[Mn(µꢀOOCBut)2]n compound, whose composition is
analogous to that of iron polymer 3). This process is acꢀ
companied by energy consumption (endothermic effect
with a shoulder) (Fig. 7). In the temperature range of
100—205 °C, the weight remains unchanged, but energy
absorption is observed, which apparently corresponds to
the structural rearrangement of the new polymer. At temꢀ
peratures above 205 °C, the weight loss and melting of the
C(9)
C(10)
C(8)
C(7)
C(6)
O(4)
O(3)
C(20)
C(23)
C(13)
C(18)
H(4D)
O(5)
C(17)
C(16)
O(7)
C(19)
C(21)
Fe(1)
C(4)
µ
eff/µ
B
C(12)
C(25)
C(24)
C(11)
C(14)
C(15)
C(2)
C(5)
O(9)
O(10)
O(1)
C(1)
O(2)
C(22)
5
O(8)
H(8D)
H(10D)
O(6)
H(6A)
C(3)
O(11)
O(12)
C(26)
C(27)
4
C(29)
C(28)
C(30)
50
100
150
200
250
T/K
Fig. 4. Structure of complex 6.
Fig. 5. Plot of µeff(T) for mononuclear complex 6.

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
811
C(10)
a
C(12)
C(11)
C(8)
C(7)
O(3)
C(9)
C(6)
O(5)
O(2)
O(4)
O(2E)
O(1E)
M(1)
C(1)
M(1B)
O(2B)
M(1D)
M(1C)
O(4E)
M(1A)
M(1F)
C(2)
O(1)
C(4)
O(5E)
C(3)
O(3E)
C(5)
C(2AB)
b
C(2AA)
C(1AA)
C(1AB)
C(7AB)
O(1AB)
O(2AB)
O(2AA)
O(3AB)
C(7AA)
O(3AA)
C(6AB)
O(4AB)
O(4A)
C(6A)
O(1AA)
Fe(1A)
O(1A)
Fe(1C)
O(3B)
C(6AA)
O(4B)
C(6B)
Fe(1D)
O(4AA)
Fe(1B)
O(2A)
O(1B)
C(1B)
C(2B)
O(2B)
C(7B)
O(3A)
C(7A)
C(1A)
C(2A)
Fig. 6. Structures of polymers 1 (M = Mn, see Ref. 6), 2 (M = Fe, see Ref. 7) (a), and 3 (see Ref. 7) (b).
intermediate occur. The melting point is 214.5 3.0 °C.
The weight loss ceases at 400 °C. Processes accompanied
by energy release start almost simultaneously with the
cessation of weight loss. The total weight loss is 75 1.5%.
The weight of the solid product is 25 1.5%. Mixedꢀvalent
oxide Mn3O4 was obtained as the final decomposition
product (Table 2).
As opposed to manganese polymer 1, the initial step of
heating of ironꢀcontaining polymer 3 is accompanied by
energy changes without changes in the weight. In the
temperature range of 100—220 °C, energy release is obꢀ
served due, apparently, to polymer destruction and the
formation of intermediate polynuclear structures. At temꢀ
peratures above 203 °C, changes accompanied by the
weight loss start. The melting point is 230.0 3.0 °C. Preꢀ
sumably, this value corresponds to a new compound, viz.,
a decomposition product of the polymer, because the
weight loss is as large as 9.5 1.5% when melting begins.
This value approximately corresponds to the loss of one
pivalate anion from four Fe(µꢀOOCBut)2 units (see
Fig. 7). On the background of complex energy changes, a
further decrease in the weight is observed, and the weight
loss is 60.5 1.5%. The total weight loss is 70 1.5%. The
weight of the solid residue is 30.0 1.5%. Iron(III) oxide
γꢀFe2O3 was obtained as the final decomposition product
(see Table 2).
The [Fe(µꢀOOCBut)2(ηꢀEtOH)]n polymer (2) is isoꢀ
structural to polymer 1. Thermolysis of 2 could be exꢀ
pected to combine the characteristic features of thermal
decomposition typical of both polymers 1 and 3. Howꢀ
ever, even the initial step of heating of 2 occurs differꢀ
ently, which is reflected in the shape of the first endotherꢀ
mic peak, where a pronounced shoulder is observed in the
temperature range of 40—80 °C. Apparently, this effect is
associated with the crystal rearrangement (see Fig. 7).
Decomposition of 2 starts at a temperature higher
than 60 °C. The initial process is accompanied by a conꢀ
siderable endothermic effect, and the weight loss is
15.1 1.5% (this step corresponds to removal of coordiꢀ
nated ethanol). Presumably, removal of ethanol gives rise

812
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
m/mg
7
5
3
Q/mW
–4
a
d
–7
–10
100
200
300
400
T/°C
100
200
300
T/°C
m/mg
Q/mW
7
5
3
b
e
1
–1
–3
100
200
300
400
T/°C
100
200
300
400
T/°C
m/mg
Q/mW
5
3
–1
–4
c
f
–7
–10
100
200
300
400
T/°C
100
200
300
400
T/°C
Fig. 7. Plots of the thermal flow vs. the temperature for polymers 1 (a), 3 (b), and 2 (c) and the integral dependence of the change in
the weight of polymers 1 (d), 3 (e), and 2 ( f ) during heating.
to a product analogous to polymer 3. The identity of 3 to
the product of decomposition of polymer 2 to 100 °C was
confirmed by calorimety (Table 3 and Fig. 8). In the
temperature range of 110—200 °C, the weight of the
thermolyzed intermediate, like that of polymer 3, remains
virtually unchanged, but energy release is observed
(blurred exothermic effect). At temperatures above 206 °C,
the weight loss starts. As in the case of 3, when melting
of 2 begins (melting point is 222.0 5.0 °C), the weight
loss is 8.0 2.0%. At temperatures above 390 °C, the exoꢀ

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
813
Table 2. Xꢀray powder diffraction analysis of decomposition products of polymer complexes 1—3
Decomposition
Decomposition
Decomposition
Mn3O4*
γꢀFe2O3**
product of 1
product of 2
product of 3
d/Å
I (%)
d/Å
I (%)
d/Å
I (%)
d/Å
I (%)
d/Å
I (%)
4.950
3.090
40
60
4.924
3.089
30
40
2.945
2.522
2.090
30
100
10
2.950
2.520
2.092
40
100
10
2.950
2.514
2.086
30
100
15
2.870
2.768
10
50
2.881
2.768
17
85
2.490
2.360
100
10
2.487
2.367
100
20
2.045
30
2.037
1.830
1.799
1.700
20
10
25
20
1.790
1.705
20
20
1.605
1.465
20
30
1.605
1.475
20
20
1.604
1.474
20
40
1.575
1.541
20
50
1.576
1.544
25
50
1.430
20
1.440
30
* Powder Diffraction File, Swarthmore: Joint Committee on Powder Diffraction Standards, card no. 24ꢀ734.
** Powder Diffraction File, Swarthmore: Joint Committee on Powder Diffraction Standards, card no. 25ꢀ1402.
Table 3. Temperature dependence of the heat capacity for
[Fe(OOCBut)2]n (1), the polymer [Fe(µꢀOOCBut)2(EtOH)]n
(2), and the product of decomposition of 2 to 100 °C
Cp/J K–1 mol–1
500
1
2
3
Т/К
Cр 2/J K–1 mol–1
3
Decomposition product of 2
2
400
300
143
153
163
173
183
193
203
213
223
233
243
253
263
273
283
293
303
243.4
254.9
266.7
276.4
285.9
297.4
307.5
317.7
328.5
339.3
348.8
359.5
369.6
378.6
389.2
395.4
405.0
243.1
254.4
267.0
275.3
285.1
296,5
306,2
316.4
327,8
338.3
348.9
360.5
369.2
378.6
389.0
395.7
404.1
294.2
315.1
325.4
340.2
351.6
362.3
374.8
386.4
400.9
409.5
420.8
432.0
444.0
456.1
464.8
476.5
487.7
190
240
290
T/K
Fig. 8. Plots of the heat capacity vs. the temperature for comꢀ
pound 3 (1), the decomposition product of 2 (2), and comꢀ
pound 2 (3).
Study of solidꢀstate thermolysis of the pivalate polyꢀ
mers unambiguously revealed a stable species existing in
the temperature range of 60—100 °C. Although the beꢀ
havior of this phase of the manganese derivatives described
by the formula [M(OOCBut)2]n differs from that of the
analogous iron derivatives, it is apparently this phase that
is most active in chemical reactions. In addition, it is
evident that decomposition of the stable phase at >200 °C
is accompanied by intramolecular oxidation of the metal
atoms because, in spite of the inert conditions (thermolyꢀ
sis was studied under argon), decomposition of the
thermic effect is observed. Decomposition is completed
at 490 °C. The total weight loss is 74.0 2.0%. The
weight of the solid product is 26.0 2.0%. Decomposition
of polymer 1, like that of polymer 3, affords γꢀFe2O3 (see
Table 2).

814
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
MnIIꢀ and FeIIꢀcontaining polymers affords oxides conꢀ
taining MnIII and FeIII ions.
Scheme 4
Unlike the carboxylate anion, which generally forms
OCO bridges, oꢀphenylenediamine molecules contain two
donor nitrogen atoms separated by two carbon atoms of
the phenylene ring (NCCN fragment). Examples, where
such molecules form a fourꢀatom bridge between VII and
VIII Group 3d transition metals, have been documented11
although these molecules generally readily form stable
fiveꢀmembered metallocycles.11—13 The latter can be oxiꢀ
dized to give metal semiquinonediimine fragments14—17
or even diimine complexes.14,18 Earlier,7 we have demonꢀ
strated that the reaction of polymer 1 with a deficiency of
1,2ꢀ(NH2)2(C6H2R2) (R = H or Me) ([Mn] : L ≥ 3 : 2)
produces the antiferromagnetic [2+1] polymers
{[(η2ꢀ(NH2)2C6H2R2)2Mn(µꢀOOCBut)2][Mn2(µꢀ
OOCBut)4]}n (8 and 9) (R = H (8) or Me (9)) containing
alternating diꢀ and mononuclear fragments. Among
these compounds, only the latter contain the chelating
oꢀphenylenediamine ligands. The ironꢀcontaining anaꢀ
i. MeCN, 80 °C, Ar.
log
{[(η2ꢀ(NH2)2C6H2R2)2Fe(µꢀOOCBut)2][Fe2(µꢀ
amine ligands, consist of alternating diꢀ and mononuclear
fragments (Fig. 9). In the dinuclear fragment of comꢀ
pound 11, the metal atoms are linked together by four
bridging carboxylate groups (Fe...Fe, 2.880(2) Å; Fe—O,
2.073(4) Å). The mononuclear fragment of the chain conꢀ
sists of the metal atom coordinated by two chelating
1,2ꢀphenylenediamine molecules and two pivalate groups
in trans positions with respect to each other, which link
the mononuclear and two dinuclear fragments (Fe...Fe,
4.533(2) Å; Fe—Fe—Fe, 144.4°; Fe—N, 2.241(5) Å;
Fe—O, 2.036(4) Å).
OOCBut)4]}n (10) (R = Me) exhibiting the ferrimagnetic
properties was synthesized analogously from polymer 2
and 1,2ꢀ(NH2)2(C6H2Me2). However, we failed to synꢀ
thesize the polymer with R = H according to this method.
In the present study, we used polymer 3 in which
coordinated ethanol molecules are absent as the starting
ironꢀcontaining reagent. It appeared that the reaction of 3
with 1,2ꢀ(NH2)2(C6H4) (MeCN, 80 °C, [Fe] : L = 3 : 2)
produces the {[(η2ꢀ(NH2)2C6H4)2Fe(µꢀOOCBut)2]ꢀ
[Fe2(µꢀOOCBut)4]•2MeCN}n polymer (11•2MeCN) in
high yield (Scheme 4).
The plot of µeff(T ) for complex 10 substantially differs
from that for complex 11 (Fig. 10). At near room temꢀ
perature, µeff of complex 11 is 8.98 µB, which is near the
theoretical limit (8.48 µB) for three weakly interacting
Xꢀray diffraction study demonstrated that polymer 11,
like its manganeseꢀcontaining analog 8, as well as derivaꢀ
tives 9 and 10 with methylꢀsubstituted oꢀphenylenediꢀ
C(8)
C(22)
C(20)
C(19)
C(7)
C(9)
C(23)
C(10)
C(6)
C(24)
C(4)
C(18)
O(4)
N(2)
O(3)
N(1)
O(2)
C(3)
C(1)
O(1)
Fe(2)
C(15)
Fe(1)
C(2)
C(5)
C(11)
O(6)
O(5)
C(12)
C(14)
C(13)
Fig. 9. Fragment of the polymer chain of complex 11.

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
815
sition of the FeII ions in the mononuclear fragments of
the polymer chain of 11 to the lowꢀspin state (S = 0). In
spite of the good quantitative description, the possibility
of the spin transition in complex 11 is somewhat doubtful
because an analogous effect has been early observed only
for FeII coordination compounds in which the FeII ions
are coordinated by six nitrogen atoms, whereas there are
only four nitrogen atoms in the complex in question.
Therefore, a decrease in µeff of 11 in the temperature
range of 100—200 K is most likely caused by a phase
transformation rather than exclusively by antiferromagꢀ
netic exchange interactions.
µ
eff/µ
B
9
8
7
6
5
a
50
100
150
200
250
T/K
For polymer 10 (R = Me), the magnetic moment
µeff gradually decreases in the temperature range of
300—140 K from 9.16 to 9.03 µB (see Fig. 10, b). The
magnetic moment µeff increases to 10.06 µB as the temꢀ
perature decreases to 30 K, which indicates that ferroꢀ
magnetic exchange interactions dominate in the crystal
of 10. Then µeff decreases to 6.96 µB at 2 K due to the
appearance of intermolecular antiferromagnetic interacꢀ
tions. We estimated exchange interactions in the repeatꢀ
ing Fe(1)...Fe(2)...Fe(3) fragment. Calculations for this
cluster in terms of the isotropic Hamiltonian were carried
out with the use of the program described in the study.19
Let us denote the exchange interaction parameter in the
dimer by J12 and the corresponding parameter between
the dimer and monomer by J23. Then the optimizaꢀ
µ
eff/µ
B
10
9
b
8
7
50
100
150
200
250
T/K
Fig. 10. Plots pf µeff(T ) for ironꢀcontaining polymers 11 (a)
and 10 (b) (theoretical data are shown by a solid curve).
tion gave the following Hamiltonian parameters: g1
g2 = 2.09(2), g3 = 2.00(2), J12 = 5.27(9) cm–1, and J23
=
=
spins S = 2 with the g factor of 2. The magnetic moment
µeff tends to saturation at ~7.1 µB with decreasing temꢀ
perature. At <20 K, the curve µeff(T ) falls off sharply and
reaches 4.87 µB at 2 K. The plot of µeff(T ) for complex 11
formally represents two types of antiferromagnetic exꢀ
change interactions different in value. It should be noted
that in the temperature range from 300 K to 50 K, strong
antiferromagnetic exchange interactions in the fourꢀbridge
dimeric fragments make the largest contribution to the
magnetic behavior of 11, whereas weaker antiferromagꢀ
netic interactions between the dimers and monomers inꢀ
volving various weak interchain exchange interactions are
efficiently included at temperatures near 20 K. The latter
interactions lead to a substantial decrease in µeff at helium
temperatures. However, the magnetic behavior of comꢀ
pound 11 is unusual in that the magnetic moment µeff is
virtually constant in the temperature range of 30—100 K,
and this value is near the theoretical limit of 6.92 µB for
two noninteracting spins S = 2 with the g factor of 2. In
our opinion, this magnetic behavior of compound 11 can
be attributed to two factors. First, this can be associated
with the fact that a decrease in the temperatures leads to
the appearance of the ferromagnetic contribution to exꢀ
change interactions between the FeII ions due, for exꢀ
ample, to structural changes in the crystal. The observed
magnetic behavior can also be accounted for by the tranꢀ
–0.18(7) cm–1, and the intermolecular exchange paramꢀ
eter nJ´ = –0.06(2) cm–1. Earlier,20 the ferromagnetic
character of exchange interactions was assumed for the
fourꢀbridge FeII dimers L2Fe2(µꢀOOCR)4 (HOOCR is
2,6ꢀdi(pꢀtolyl)benzoic acid and L is benzylamine or
methoxybenzylamine). Recently,10 the strong ferromagꢀ
netic contribution to exchange interactions in the diꢀ
nuclear complex (2,3ꢀMe2C5H3N)2Fe2(µꢀOOCBut)4 has
been explained based on calculations taking into account
the orbital component.
As expected, an excess of the oꢀphenylenediamine
ligands in the reaction mixture leads to the formation of
mononuclear complexes. For example, the reaction with
an excess of 1,2ꢀphenylenediamine ([Fe] : L = 1 : 4) or
4,5ꢀdimethylꢀ1,2ꢀphenylenediamine ([Fe] : L = 1 : 3)
with the tetranuclear complex Fe4(µ3ꢀOH)2(µꢀ
OOCBut)4(η2ꢀOOCBut)2(η1ꢀEtOH)6 (7) (or polymer 3)
in ethanol at 80 °C produces the Fe(η1ꢀOOCBut)2(η1ꢀ
(NH2)2C6H4)4
(12)
and
Fe(η1ꢀOOCBut)2(η2ꢀ
(NH2)2C6H2Me2)(η1ꢀ(NH2)2C6H2Me2)2 (13) complexes,
respectively, in good yields (40% for 12 and 61% for 13)
(Scheme 5).
Xꢀray diffraction study (Fig. 11) demonstrated that
the iron atom in complex 12 is in a distorted octahedral
coordination environment formed by four nitrogen atoms
of the amino groups of four diamine ligands in the equaꢀ

816
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
Scheme 5
torial plane (Fe—N, 2.256(2)—2.322(2) Å; N—Fe—N,
86.83(7)—93.51(7)°) and two oxygen atoms of the carꢀ
boxylate groups in the axial positions (Fe—O, 2.0344(18)
and 2.0425(18) Å; O—Fe—O, 179.31(7)°). In the crystal,
the molecules of the mononuclear complex are linked
to each other by hydrogen bonds between the protons
of the free amino groups of the diamine ligands and
the oxygen atoms of the terminal pivalate groups
(N(NH2)...O(OOCR), 2.844 and 2.885 Å) to form a
supramolecular network (see Fig. 11). In addition, there
are stacking interactions between the phenylene rings of
the oꢀphenylenediamine ligands of the adjacent molecules
(distances between the planes of the rings are in the range
of 3.424—3.490 Å).
Complex 13, unlike mononuclear complex 12, conꢀ
tains only three diamine ligands, one of them being coorꢀ
dinated in a chelate fashion (Fig. 12). The equatorial
plane in complex 13, like that in 12, is formed by
four nitrogen atoms of four amino groups (Fe—N,
2.204(2)—2.258(2) Å; N—Fe—N(η2ꢀL), 74.61(8)°
and 74.57(4)°; N—Fe—N, 92.28(8)—97.42(8)° and
92.59(8)—96.39(8)° in two independent molecules). Two
oxygen atoms of the pivalate ligands are in the axial poꢀ
sitions (Fe—O, 2.081(2)—2.0931(18) Å; O—Fe—O,
172.27(7)°, 170.64(8)°). The molecules of the monoꢀ
nuclear complex in the crystal structure of 13 are
also linked to each other by hydrogen bonds
(N(NH2)...O(OOCR), 2.814—2.989 Å) and stacking inꢀ
i. EtOH, 80 °C, Ar.
N(8C)
N(4)
O(2B)
N(3)
O(2)
O(1)
N(8)
N(7)
Fe(1)
N(5)
N(6)
O(3)
O(4)
N(1)
O(4A)
N(6D)
N(2)
Fig. 11. Fragment of the crystal packing of mononuclear complex 12.

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
817
C(34)
C(31)
C(30)
N(6)
C(32)
C(59)
C(60)
C(10)
C(7)
C(9)
C(8)
C(27)
C(55)
C(56)
C(44)
C(25)
C(42)
C(43)
C(29)
O(3)
N(5)
C(33)
C(54)
C(28)
C(20)
N(3)
C(6)
C(41)
N(10)
C(21)
C(57)
O(4)
C(22)
C(26)
C(40)
O(8)
Fe(1)
C(19)
C(24)
C(53)
C(58)
C(49)
N(2)
O(7)
N(7)
C(23)
N(4)
N(1)
C(50)
Fe(2)
O(1)
C(1)
N(8)
O(2)
C(11)
C(12)
C(52)
C(45)
C(62)
C(67)
C(48)
C(4)
C(16)
N(9)
O(6)
C(47)
O(5)
C(2)
N(11)
C(61)
C(63)
C(64)
C(15)
C(3)
C(46)
C(35)
C(66)
C(51)
C(5)
C(13)
C(14)
C(37)
C(36)
N(12)
C(68)
C(65)
C(17)
C(38)
C(39)
C(18)
Fig. 12. Structure of complex 13 (two crystallographically independent geometrically similar molecules are shown).
teractions (distances between the planes of the phenylene
fragments in the adjacent molecules are in the range of
3.367—3.623 Å) to form a supramolecular network (see
Fig. 12).
The magnetic behavior of 12 and 13 is similar to that
of mononuclear complex 6. The effective magnetic moꢀ
ments of 12 and 13 are very weakly temperatureꢀdepenꢀ
dent in the range of 300—20 K (5.00—4.93 µB for 12 and
5.00—4.96 µB for 13) (Fig. 13). Only at helium temperaꢀ
tures, µeff monotonically decreases (4.66 µB (4.2 K) for 12
and 4.12 µB (2 K) for 13) due to the appearance of weak
intermolecular antiferromagnetic exchange interactions.
As a result, the reaction with an excess of oꢀphenyleneꢀ
diamines, like the reactions of the iron polymer with
pivalic acid, leads to degradation of the polymeric strucꢀ
ture and the formation of mononuclear complexes.
The polymeric MnII and FeII pivalates under study are
suitable for use as the starting "spin materials" from which
magnetic molecules with a desired geometry can be genꢀ
erated. In this case, information on the tendency of the
manganese derivative to retain a polynuclear (even polyꢀ
meric) structure in the presence of excess carboxylic acid
or oꢀphenylenediamine is undoubtedly useful in the deꢀ
velopment of procedures for the formation of nanosized
molecular magnets containing high spin MnII atoms. The
possibility to generate carboxylate or diamine monomers
with FeII atoms, which are readily soluble in hydrocarꢀ
bons, holds promise that new procedures will be develꢀ
oped for the formation of heteronuclear magnetic strucꢀ
tures assembled from such monomers and coordinaꢀ
tively unsaturated magnetoactive polymers analogous
to compound 1. All polymeric MnII pivalates have the
antiferromagnetic properties in spite of substantial strucꢀ
tural differences. At the same time, analogous FeII deꢀ
rivatives exhibit the ferromagnetic properties. This fact
is important for the choice of the starting "spin mateꢀ
rial" and, apparently, should be taken into account when
designing the process of assembly of new molecular
magnets.
µ
eff/µ
B
4.8
4.4
a
b
50
100
150
200
250
T/K
Fig. 13. Plots of µeff(T ) for mononuclear complexes 12 (a)
and 13 (b).

818
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
P o l y [ ( µ 3 ꢀ h y d r o x y ) ( η 2 , µ 3 ꢀ t r i m e t h y l a c e t a t o ꢀ
Experimental
2
O,O,O´,O´)tris(µ ꢀtrimethylacetatoꢀO,O,O´)(η ,µ ꢀtriꢀ
3
2
methylacetatoꢀO,O,O´)tris(µ ꢀtrimethylacetatoꢀO,O´)(µ ꢀ
2
2
1
1
1
The complexes were synthesized under pure argon with
chloro)(η ꢀaquo)(η ꢀacetonitrile)(η ꢀtrimethylacetic
acid)pentamanganese(II)], solvate with acetonitrile,
the use of freshly distilled solvents. The starting
[Mn(OOCBut)2(HOEt)]n (1),6 [Fe(OOCBut)2]n (3),7 and
{(MeCN)(HOOCBut)(H2O)Mn5Cl(OH)(OOCBut)8•MeCN}n,
(4•MeCN). Weighed samples of MnCl2•4H2O (0.5 g,
2.53 mmol) and KOOCBut (0.47 g, 3.37 mmol) in EtOH (20 mL)
were stirred at 80 °C for 1 h. The solution was filtered and
concentrated to dryness. Acetonitrile (30 mL) was added to the
dry reaction product, and the reaction mixture was stirred at
80 °C for 2 h. The solution was filtered off, concentrated to
15 mL, and kept at 10 °C for 48 h. Colorless crystals of complex
4•MeCN suitable for Xꢀray diffraction study were separated
from the solution by decantation, washed with cold MeCN
(0 °C), and dried under a stream of argon. The yield was 0.31 g
2
1
[Fe4(µ ꢀOH)2(µꢀOOCBut)4(η ꢀOOCBut)2(η ꢀEtOH)6]•2EtOH
3
(7•2EtOH)7 compounds were synthesized according to known
procedures. Commercial MnCl2•4H2O (special purity), KOH
(chemical purity), pivalic acid, 4,5ꢀdimethylꢀ1,2ꢀphenylenediꢀ
amine, and 1,2ꢀphenylenediamine (Fluka) were used in the synꢀ
thesis of new compounds.
The IR spectra were recorded on a Specord Mꢀ80 instruꢀ
ment in KBr pellets. The magnetochemical measurements were
performed at the International Tomography Center of the Sibeꢀ
rian Branch of the Russian Academy of Sciences (Novosibirsk)
on a SQUID magnetometer (MPMSꢀ5S Quantum Design) in
the temperature range of 2—300 K using the magnetic field
intensity of up to 5 kOe. The molar magnetic susceptibility (χ)
was calculated taking into account the atomic diamagnetism
according to the additive Pascal scheme. In the paramagnetic
(46%). Found (%): C, 44.1; H, 6.7; N, 2.2. C49H90ClMn5N2O20
Calculated (%): C, 44.01; H, 6.78; N, 2.09. IR (KBr), ν/cm–1
.
:
3440 br.m, 2960 s, 2932 m, 2868 m, 1652 m, 1580 s, 1560 s,
1536 s, 1512 s, 1484 s, 1460 m, 1424 s, 1376 s, 1360 s, 1228 s,
1032 w, 9400 v.s, 896 m, 792 m, 716 v.s, 604 m, 552 w, 416 m.
2
region, the effective magnetic moment was calculated by the
Poly[bis(η ,µ ꢀtrimethylacetatoꢀO,O,O´,O´)(µ ꢀtrimethylꢀ
3
3
2
equation µ = [(3k/NAβ )χT ]1/2 ≈ (8χT )1/2 21
,
where k is the
acetatoꢀO,O,O´)pentakis(µ ꢀtrimethylacetatoꢀO,O´)(µ ꢀtriꢀ
eff
2
2
1
Boltzmann constant, NA is Avogadro's number, and β is the
Bohr magneton.
methylacetic acid)(η ꢀtrimethylacetic acid)tetramanganese(II)],
[Mn4(OOCBut)8(HOOCBut)2]n (5). Hexane (or MeCN)
(15 mL) was added to a mixture of compound 1 (0.4 g,
1.32 mmol) and HOOCBut (0.27 g, 2.6 mmol). The reaction
mixture was stirred at 65 °C for 30 min. The colorless solution
was concentrated to 7 mL and kept at 20 °C for 48 h. Colorless
crystals of complex 5 suitable for Xꢀray diffraction study were
separated from the solution by decantation, washed with cold
hexane (0 °C), and dried under a stream of argon. The yield was
Thermal decomposition of compounds 1—3 was studied
by differential scanning calorimetry and thermogravimetry
on DSCꢀ20 and TGꢀ50 units of a TAꢀ3000 thermoanalyzer
(Mettler). Samples were heated under dry argon at a constant
rate (in all experiments) of 5 deg min–1. For each compounds,
four differential scanning calorimetry experiments and three
thermogravimetry experiments were performed. The weight loss
upon thermal destruction was determined directly on a TGꢀ50
thermobalance; the accuracy of weighing was 2•10–3 mg.
Stepwise thermal decomposition was studied by differential scanꢀ
ning calorimetry, which involved the division of the total temꢀ
perature range into parts. The size and number of these parts
were determined based on the overall pattern of the weight and
energy changes upon decomposition. This approach allowed us
to determine the weight loss in each temperature range and
compare the results of DSC with the thermogravimetric data.
The results of these methods were in satisfactory agreement,
which confirms the reliability of the experimental data. The
accuracy of the determination of the anomalous points and therꢀ
mal effects in the thermograms was 1° and 0.5%, respecꢀ
tively.
The heat capacity was measured on a DSCꢀ30 unit of a
TAꢀ4000 thermoanalyzer, which is a differential scanning caloꢀ
rimeter operating in the temperature scanning mode and deꢀ
signed for quantitative thermal measurements. The heat capacꢀ
ity was determined with a relative error of 2—3%. The systemꢀ
atic measurement error was estimated by determining the therꢀ
mal capacities of wellꢀstudied compounds at regular intervals.
The deviations of the measured heat capacities of corundum
from the values reported by the National Bureau of Standards
(NBS) were 1—2%.
0.31 g (76%). Found (%): C, 48.7; H, 7.2. C50H90Mn4O20
.
Calculated (%): C, 48.79; H, 7.37. IR (KBr), ν/cm–1: 2964 s,
2908 m, 2872 m, 1688 m, 1588 s, 1520 w, 1484 s, 1456 m,
1424 m, 1408 m, 1360 m, 1320 w, 1224 s, 1208 s, 1032 w, 940 w,
900 m, 872 w, 788 m, 768 w, 600 m, 568 w, 536 m, 408 m.
1
1
Bis(η ꢀtrimethylacetato)tetrakis(η ꢀtrimethylacetic
1
1
acid)iron(II), Fe(η ꢀHOOCBut)4(η ꢀOOCBut)2 (6). A. A soluion
of HOOCBut (0.5 g, 4.9 mmol) in hexane (15 mL) was added to
7•2EtOH (0.26 g, 0.22 mmol). The reaction mixture was stirred
at 65 °C for 20 min until a colorless solution was obtained. Then
the solution was concentrated to 4 mL and kept at 10 °C for 24 h.
Colorless crystals of complex 6 suitable for Xꢀray diffraction
study were separated from the solution by decantation, washed
with cold hexane (0 °C), and dried under a stream of argon.
The yield was 0.41 g (72%). Found (%): C, 54.0; H, 8.6.
C30H58FeO12. Calculated (%): C, 54.03; H, 8.77. IR (KBr),
ν/cm–1: 2968 s, 2928 m, 2868 m, 1696 s, 1592 s, 1536 w, 1484 s,
1456 m, 1424 s, 1376 m, 1364 m, 1316 w, 1228 s, 1208 m,
1092 v.s, 1032 w, 940 v.s, 900 w, 876 w, 788 w, 764 v.s, 716 w,
604 m, 540 w, 436 m.
B. A solution of HOOCBut (0.20 g, 2.0 mmol) in hexane
(10 mL) was added to compound 3 (0.10 g, 0.39 mmol). The
reaction mixture was stirred at 65 °C for 1 h until a colorless
solution was obtained. Then the solution was concentrated to
3 mL and kept at 10 °C for 24 h. Colorless crystals of complex 3
suitable for Xꢀray diffraction study were separated from the soꢀ
lution by decantation, washed with cold hexane (0 °C), and
dried under a stream of argon. The yield was 0.20 g (76%).
Found (%): C, 53.9; H, 8.5. C30H58FeO12. Calculated (%):
Xꢀray powder diffraction analysis was carried out on an
FRꢀ552 monochromator chamber (CuꢀKα radiation) using gerꢀ
1
manium as the internal standard (Xꢀray diffraction patterns were
processed on a IZAꢀ2 comparator with an accuracy of 0.01 mm)
and with the use of the STOE Powder Diffraction System.

Reactions of MnII and FeII polymeric pivalates
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
819
C, 54.03; H, 8.77. IR (KBr), ν/cm–1: 2968 s, 2928 m, 2868 m,
1696 s, 1592 s, 1536 w, 1484 s, 1456 m, 1424 s, 1376 m, 1364 m,
1316 w, 1228 s, 1208 m, 1092 v.s, 1032 w, 940 v.s, 900 w, 876 w,
788 w, 764 v.s, 716 w, 604 m, 540 w, 436 m.
The structures of all complexes were solved by direct methꢀ
ods and refined by the fullꢀmatrix leastꢀsquares method with
anisotropic displacement parameters for all nonhydrogen atoms.
The hydrogen atoms of the tertꢀbutyl substituents of the pivalate
ligands as well as the hydrogen atoms of the Me groups and the
phenylene fragments of oꢀphenylenediamines were calculated
geometrically and refined using a riding model. The protons of
the hydroxo groups of the coordinated trimethylacetic acid molꢀ
ecules and the amino groups of the diamine ligands were found
in difference Fourier maps and refined isotropically. All calcuꢀ
lations were performed with the use of the SHELX97 program
package.26 Crystallographic parameters and structure refinement
details are given in Table 1.
2
Poly[hexakis(µ ꢀtrimethylacetatoꢀO,O´)(η ꢀ1,2ꢀphenyleneꢀ
2
diamineꢀN,N´)triiron(II)],
solvate
with
acetonitrile,
2
{[(η ꢀ(NH2)2C6H4)2Fe(µꢀOOCBut)2][Fe2(µꢀOOCBut)4]•
•2MeCN}n, (11•2MeCN). A solution of 1,2ꢀphenylenediamine
(0.025 g, 0.25 mmol) in MeCN (20 mL) was added to comꢀ
pound 3 (0.09 g, 0.35 mmol), and the reaction mixture was
stirred at 80 °C for 30 min. Then the solution was concentrated
to 10 mL at 60 °C and kept at room temperature for two days.
Colorless crystals of complex 11•2MeCN suitable for Xꢀray
diffraction study were separated from the solution by decantaꢀ
tion, washed with cold MeCN (0 °C), and dried under a stream
of argon. The yield was 0.10 g (80%). Found (%): C, 51.8;
H, 7.3; N, 7.4. C46H76Fe3N6O12. Calculated (%): C, 51.48;
H, 7.14; N, 7.83. IR (KBr), ν/cm–1: 3358 m, 3284 m, 2960 s,
2924 s, 2872 m, 1584 s, 1552 m, 1532 m, 1484 s, 1456 m, 1429 s,
1376 m, 1360 m, 1280 w, 1224 m, 1064 w, 1032 m, 940 w, 896 w,
856 w, 844 w, 788 m, 744 w, 716 w, 604 m, 532 w, 432 m.
This study was financially supported by the Russian
Foundation for Basic Research (Project Nos 04ꢀ03ꢀ32880,
04ꢀ03ꢀ32883, 05ꢀ03ꢀ32767, 05ꢀ03ꢀ32794, and 05ꢀ03ꢀ
08203), INTAS (Grant 03ꢀ51ꢀ4532), the US Civilian Reꢀ
search and Development Foundation (CRDF, Grant
Y1ꢀCꢀ08ꢀ12), and the Russian Academy of Sciences (Tarꢀ
get Program for Basic Research of the Division of Chemꢀ
istry and Materials Science of the Russian Academy of
Sciences "Chemistry and Physical Chemistry of Supramoꢀ
lecular Systems and Atomic Clusters" and the Program of
the Presidium of the Russian Academy of Sciences "Moꢀ
lecular Design of Magnetoactive Compounds and Mateꢀ
rials (Molecular Magnets)").
1
1
Bis(η ꢀtrimethylacetato)tetrakis(η ꢀ1,2ꢀphenylenediamiꢀ
1
1
neꢀN )iron(II), Fe(η ꢀ(NH2)2C6H4)4(η ꢀOOCBut)2 (12). The
complex 7•2EtOH (0.14 g, 0.12 mmol) and 1,2ꢀphenylenediꢀ
amine (0.2 g, 1.85 mmol) in EtOH (10 mL) were stirred at 80 °C
for 30 min. The resulting colorless solution was concentrated to
3 mL and kept at 10 °C for 24 h. Colorless crystals of complex 12
suitable for Xꢀray diffraction study were separated from the soꢀ
lution by decantation, washed with cold EtOH (0 °C), and dried
under a stream of argon. The yield was 0.13 g (40%). Found (%):
C, 59.3; H, 7.4; N, 16.4. C34H50FeN8O4. Calculated (%):
C, 59.10; H, 7.30; N, 16.23. IR (KBr), ν/cm–1: 3544 m, 3388 s,
3364 s, 3320 s, 3252 m, 2960 s, 2928 m, 2868 m, 1620 s, 1600 s,
1532 s, 1500 s, 1476 m, 1464 m, 1412 m, 1372 m, 1356 m,
1276 m, 1224 w, 1148 v.s, 1128 v.s, 1076 w, 1016 s, 928 v.s,
920 v.s, 888 w, 856 m, 796 m, 744 s, 596 m, 516 v.s, 464 m,
440 w, 408 w.
References
1. B. Singh, J. R. Long, F. F. de Biani, D. Gatteschi, and
P. Stavropoulos, J. Am. Chem. Soc., 1997, 119, 7030.
2. W. Wang, C. Ma, X. Zhang, C. Chen, Q. Liu, F. Chen,
D. Liao, and L. Li, Bull. Chem. Soc. Jpn, 2002, 75, 2609.
3. A. J. Tasiopoulos, N. C. Harden, K. A. Abboud, and
G. Christou, Polyhedron, 2003, 22, 133.
4. P. Christian, G. Rajaraman, A. Harrison, M. Helliwell, J. J.
W. McDouall, J. Raftery, and R. E. P. Winpenny, Dalton
Trans., 2004, 2550.
5. D. Huang, W. Wang, X. Zhang, C. Chen, F. Chen, Q. Lui,
D. Liao, L. Li, and L. Sun, Eur. J. Inorg. Chem., 2004, 1454.
6. M. A. Kiskin, I. G. Fomina, G. G. Aleksandrov, A. A.
Sidorov, V. N. Novotortsev, Y. V. Rakitin, Z. V.
Dobrohotova, V. N. Ikorskii, Y. G. Shvedenkov, I. L.
Eremenko, and I. I. Moiseev, Inorg. Chem. Commun.,
2005, 8, 89.
7. I. L. Eremenko, M. A. Kiskin, I. G. Fomina, A. A. Sidorov,
G. G. Aleksandrov, V. N. Ikorskii, Yu. G. Shvedenkov, Yu. V.
Rakitin, and V. M. Novotortsev, J. Cluster Sci., 2005, 16, 331.
8. M. A. Kiskin, Ph. D. (Chem.) Thesis, N. S. Kurnakov Instiꢀ
tute of General and Inorganic Chemistry, Russian Academy
of Sciences, Moscow, 2005 (in Russian).
1
2
Bis(η ꢀtrimethylacetato)(η ꢀ4,5ꢀdimethylꢀ1,2ꢀphenyleneꢀ
1
diamineꢀN,N´)bis(η ꢀ4,5ꢀdimethylꢀ1,2ꢀphenylenediamineꢀ
2
1
1
N )iron(II), Fe(η ꢀ(NH2)2C6H2Me2)(η ꢀ(NH2)2C6H2Me2)2(η ꢀ
OOCBut)2 (13). A mixture of the complex 7•2EtOH (0.2 g,
0.17 mmol) and 4,5ꢀdimethylꢀ1,2ꢀphenylenediamine (0.27 g,
2.0 mmol) in EtOH (10 mL) was stirred at 80 °C for 30 min. The
resulting paleꢀbrown solution was concentrated to 5 mL and
kept at 10 °C for 24 h. Colorless crystals of complex 13 suitable
for Xꢀray diffraction study were separated from the solution by
decantation, washed with cold EtOH (0 °C), and dried under a
stream of argon. The yield was 0.27 g (61%). Found (%): C, 61.3;
H, 8.0; N, 12.7. C34H54FeN6O4. Calculated (%): C, 61.23;
H, 8.17; N, 12.61. IR (KBr), ν/cm–1: 3548 m, 3488 s, 3416 s,
3324 s, 3232 m, 2960 s, 2928 m, 2864 m, 1616 s, 1588 s, 1552 m,
1516 s, 1480 m, 1456 w, 1404 m, 1360 m, 1352 m, 1300 w,
1260 v.s, 1224 m, 1092 v.s, 1020 w, 984 m, 884 w, 860 w, 828 v.s,
792 w, 716 v.s, 600 m, 552 v.s, 424 w, 408 w.
Xꢀray diffraction study of complexes 4—6 and 11—13. Xꢀray
diffraction studies were carried out at the Xꢀray Structural Cenꢀ
ter (A. N. Nesmeyanov Institute of Organoelement Comꢀ
pounds of the Russian Academy of Sciences) on a Bruker AXS
SMART 1000 diffractometer22—24 equipped with a CCD detecꢀ
tor (λMo, graphite monochromator, 110 K, ω scanning techꢀ
nique with a step of 0.3°, exposure time per frame was 30 s).
9. V. N. Novotortsev, Y. V. Rakitin, V. N. Ikorskii, and I. L.
Eremenko, Mendeleev Commun., 2006, 1.
10. Yu. V. Rakitin, V. M. Novotortsev, V. N. Ikorskii, and I. L.
Eremenko, Izv. Akad. Nauk, Ser. Khim., 2004, 2035 [Russ.
Chem. Bull., Int. Ed., 2004, 53, 2124].
11. A. E. Malkov, G. G. Aleksandrov, V. N. Ikorskii, A. A.
Sidorov, I. G. Fomina, S. E. Nefedov, V. M. Novotortsev,

820
Russ.Chem.Bull., Int.Ed., Vol. 55, No. 5, May, 2006
Kiskin et al.
I. L. Eremenko, and I. I. Moiseev, Koord. Khim., 2001, 27,
636 [Russ. J. Coord. Chem., 2001, 27 (Engl. Transl.)].
12. K. R. Maxcy, R. Smith, R. D. Willett, and A. Vij,
Acta Crystallogr., Sect. C: Cryst. Struct. Commun., 2000,
56, e454.
Eremenko, Izv. Akad. Nauk, Ser. Khim., 2002, 1453 [Russ.
Chem. Bull., Int. Ed., 2002, 51, 1581].
19. I. V. Ovcharenko, Yu. G. Shvedenkov, R. N. Musin, and
V. N. Ikorskii, Zh. Strukt. Khim., 1999, 40, 36 [Russ. J. Struct.
Chem., 1999, 40 (Engl. Transl.)].
13. A. E. Malkov, I. G. Fomina, A. A. Sidorov, G. G.
Aleksandrov, V. N. Ikorskii, V. M. Novotortsev, and I. L.
Eremenko, Izv. Akad. Nauk, Ser. Khim., 2003, 489 [Russ.
Chem. Bull., Int. Ed., 2003, 52].
20. S. Yoon and S. J. Lippard, Inorg. Chem., 2003, 42, 8606.
21. Yu. V. Rakitin and V. T. Kalinnikov, Sovremennaya
magnetokhimiya [Modern Magnetochemistry], Nauka, St. Peꢀ
tersburg, 1994, 272 (in Russian).
14. S.ꢀM. Peng, C.ꢀT. Chen, D.ꢀS. Liaw, C.ꢀI Chen, and
Y. Wang, Inorg. Chim. Acta, 1985, 101, L31.
22. SMART (Control) and SAINT (Integration) Software, Verꢀ
sion 5.0, Bruker AXS Inc., Madison (WI), 1997.
23. G. M. Sheldrick, SADABS, Program for Scanning and Corꢀ
rection of Area Detector Data, Göttingen University,
Göttinngen (Germany), 1997.
24. G. M. Sheldrick, SHELX97, Program for the Solution of
Crystal Structures, Göttingen University, Götinngen (Gerꢀ
many), 1997.
15. D. Herebian, E. Bothe, F. Neese, T. Weyhermuller, and
K. Wieghardt, J. Am. Chem. Soc., 2003, 125, 9116.
16. E. Bill, E. Bothe, P. Chaudhuri, K. Chlopek, D. Herebian,
S. Kokatam, K. Ray, T. Weyhermuller, F. Neese, and
K. Wieghardt, Chem. Eur. J., 2005, 11, 204.
17. A. V. Reshetnikov, A. A. Sidorov, S. S. Talismanov, G. G.
Aleksandrov, Yu. A. Ustynyuk, S. E. Nefedov, I. L.
Eremenko, and I. I. Moiseev, Izv. Akad. Nauk, Ser. Khim.,
2000, 1794 [Russ. Chem. Bull., Int. Ed., 2000, 49, 1771].
18. I. G. Fomina, A. A. Sidorov, G. G. Aleksandrov, V. N.
Ikorskii, V. M. Novotortsev, S. E. Nefedov, and I. L.
Received January 18, 2006;
in revised form April 13, 2006