High-Energy-Capacity Cobalt(III) Tetrazolates

Article abstract of DOI:10.1023/A:1025778918488

Physicochemical and explosive properties of cobalt(III) tetrazolate perchlorate complexes were studied. The spectrophotometical properties of these complexes in the solid state and their sensitivity to laser radiation were examined.

Full text of DOI:10.1023/A:1025778918488

Russian Journal of Applied Chemistry, Vol. 76, No. 4, 2003, pp. 572 576. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 4, 2003,
pp. 592 596.
Original Russian Text Copyright
2003 by Zhilin, Ilyushin, Tselinskii, Kozlov, Lisker.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
High-Energy-Capacity Cobalt(III) Tetrazolates
A. Yu. Zhilin, M. A. Ilyushin, I. V. Tselinskii, A. S. Kozlov, and I. S. Lisker
St. Petersburg State Technological Institute, St. Petersburg, Russia
Agrophysical Institute, St. Petersburg, Russia
Received May 30, 2002
Abstract Physicochemical and explosive properties of cobalt(III) tetrazolate perchlorate complexes were
studied. The spectrophotometical properties of these complexes in the solid state and their sensitivity to
laser radiation were examined.
Tetramminebis(5-nitrotetrazolato)cobalt(III) perchlo-
rate I is used as an explosive in priming charges (PCs)
photosensitive compounds since they are safer than
conventional primers used in laser detonators [3].
This study is concerned with a series of tetraminetetra-
zolato Co(III) perchlorates with the general formula
initiated with a laser diode ( = 800 nm, Ebeam
=
0.5 mJ) [1, 2]. Both I and its analogs are promising
[Co(NH3)4(Tz)n ](ClO4]m,
n = 2, m = 1 (I IV); n = 1, m = 1 (V); n = 2, m = 3 (VI, VII);
NO2
H
CH3
(III),
NH2
(IV),
N NO2 H2N
NH2 H3C
CH3
(VII).
N
N
N
N
N
N
N
N
(VI),
Tz =
(I),
(II),
(V),
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Compounds I VII were prepared by the reaction
[Co(NH3)4(H2O)2](ClO4)3 + nTz
Thermolysis of I VII was studied under nonisother-
1
mal conditions at a heating rate of 5 deg min . These
compounds are relatively thermostable since their Toid
temperature is higher than 230 C. In the first stage
of thermolysis of tetrazolatotetrammine cobalt(III) per-
chlorates, the inner coordination sphere of this com-
plex degrades with elimination of ammonia. Then tet-
razole ligands are thermally decomposed with their
stepwise oxidation by outer-sphere perchlorate anions
[5]. The thermal analysis curves of I and VII contain
a broad exothermic peak corresponding to simultane-
ous occurrence of these steps. Clearly, in this case, the
energy liberation is at a maximum and the energy loss,
at a minimum. As a result, the combustion detonation
transition for I and VII is the fastest. For II and IV, the
three thermolysis steps are separated in time. The total
exothermic effect is lower owing not only to endo-
thermic elimination of ammonia, but also to removal
of the fuel from the reaction zone. A nonstoichiomet-
ric ratio of the fuel and oxidizing agent may result in
VIII
HClO4/H2O, pH < 2,
95 C, 4 h
(1)
[Co(NH3)4(Tz)n](ClO4)m + 2H2O.
I VII
The complexes are crystalline compounds soluble
in water, DMSO, DMF and difficulty soluble in etha-
nol, isopropanol, and isobutanol. Their physicochem-
ical and explosive characteristics are summarized in
the table.
The densities of Co(III) tetramine complexes were
calculated as sums of molecular increments of struc-
3
tural fragments with average error of 0.04 g cm .
To determine the detonation rate of I VII, their mol-
ecules were divided into active (perchlorate anion and
the ligands) and inert (metal cation) parts. The detona-
tion rate was calculated from these increments with
1
average error of 140 m s [4].
1070-4272/03/7604-0572 $25.00 2003 MAIK Nauka/Interperiodica

HIGH-ENERGY-CAPACITY COBALT(III) TETRAZOLATES
573
Physicochemical and explosive characteristics of (tetramminetetrazolato)cobalt(III) perchlorates
Compound
Property
I
II
III
IV
V
VI
VII
3
Density, , g cm
Detonation rate D , km s
1.97*
8.1
1.86
6.9
1.75
6.8
1.81
6.7
1.90
7.1
1.85
7.3
1.90*
7.5
1
Onset temperature of intense decomposition Toid
,
C
234
239
64
0.45
252
242
14
0.50
238
10
0.40
233
32
0.35
234
Shock sensitivity H25/cm, %**
8
0.05
8
0.15
Minimal priming charge (MIC), g
0.30
*
Experimental values.
**
Load 2 kg, sample weight 20 mg.
additional heat loss and longer combustion detonation
transition, which is actually the case (see table). In
thermolysis of III, V, and VI, the pattern is interme-
diate between those observed with I, VII and II, IV.
into a doublet is due to nonequivalence of the am-
monia protons. This splitting is caused by coordina-
tion of the tetrazole ring via different atoms: N1 and
N2 in II and IV [9], N1 and O of one of the nitro
groups in V (5-nitroaminotetrazole is coordinated in
the bidentate manner) [10], and N3 and N4 in VI and
VII [11]. The tetrazole ligands of I are coordinated
only via the N2 atom [12].
The kinetic parameters of thermolysis of I VII at
Toid were calculated from the T TG, T DTG, and
T DTA curves. The preexponential factor in the Ar-
1
rhenius equation, activation energy (kJ mol ), and
reaction order are 18.5, 212.2, 0.5; 18.8, 228.6, 0.5;
16.7, 204.7, 1.0; 26.3, 293.3, 0.5; 17.6, 231.6, 1.0;
17.4, 204.6, 1.0; and 18.6, 218.3, 1.0, respectively.
The fact that the reaction order of thermolysis is lower
than unity (n = 0.5) is presumably due to occurrence
of the reaction at the interface between sample and the
reaction product and the influence of the crystal lattice
on the diffusion of the reaction products [6]. The reac-
tion order equal to 1.0 indicates that thermolysis is not
hindered by diffusion factors.
We also studied the sensitivity of pressed powders
of the explosives to a single pulse of neodymium
solid-state laser ( = 1.06 m,
= 2 ms, E = 1.5 J,
dbeam = 1 mm). The results obtaiqned are listed below.
Compound
Effect
I
II
III
IV
V
Detonation
Combustion
Failure
Detonation
Failure
The IR spectra of I VII contain absorption bands
associated with coordinated ammonia, substituents in
the heterocyclic ring, tetrazole ring, and outer-sphere
perchlorate anion.
VI
VII
Detonation
Failure
The modern concept of initiation of explosives
with pulsed laser radiation is based on the ignition at
centers formed upon hypothesis of radiation absorp-
tion by optical microheterogeneities in separate crys-
tals [3]. In this context, a spectral study of the prim-
ers in the wavelength range used in industrial lasers
(visible and near-IR region, ruby laser operating at
690 nm and neodymium laser operating at 1060 nm)
is of not only theoretical, but also practical interest.
The electronic absorption spectra of I VII in aque-
ous solutions are typical of this type of compounds [7]
1
and contain the d d band of T1g
1A1g transition.
The other strong band (1T2g
1A2g) is overlapped by
the absorption of the tetrazole ligand. Clearly, these
complexes contain the octahedral chromophore CoN6.
1
The H NMR spectra of all the compounds except
III contain signals of equatorial (in low field) and
ax. (in high field) ammonia ligands in the range 3.4
4.3 ppm. In the spectrum of III, the ammonia H
signal is not split, probably owing to trans config-
uration of the complex. The different chemical shifts
of the equatorial and ax. ammonia molecules are con-
sistent with coordination of the heterocyclic ligands
via nitrogen atoms [8]. The splitting of these signals
We recorded optical spectra of crystalline com-
plexes I III and IV (in pellets). First we recorded
the spectra of I and II. Since the influence of the
material brought in contact with primers in priming
charges (PCs) is of practical interest, pellets of the
compounds examined were placed on a copper sup-
port (Figs. 1, 2).
1
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574
ZHILIN et al.
Fig. 1. Diffuse reflectance spectra of (a) I and (b) II. (K ) Diffuse reflectance coefficient and ( ) wavelength. (1) No support and
d
(2) on a support; the same for Fig. 2.
Fig. 2. Electronic absorption spectra of (a) I and (b) II (K ) Absorption coefficient and ( ) wavelength.
a
Fig. 3. (a) Mirror reflectance, (b) absorption, and (c) diffuse reflectance spectra of (1) I, (2) II, (3) III, and (4) VI on a support.
(K , K , K ) Coefficeints of mirror reflectance, absorption, and diffuse reflectance, respectively; ( ) wavelength.
m
a
d
As seen from Figs. 1 and 2, compounds I and II
behave similarly under exposure to radiation in the
whole spectral range, including the wavelength of the
neodymium laser (1060 nm). In all cases, the copper
support affects the spectral properties. To confirm this
result, we also recorded the spectra of III and VI
(Figs. 3a 3c).
priming charges and in optically initiated priming
charges of high safety.
EXPERIMENTAL
The IR spectra of crystalline I VII (Nujol or fluo-
rinated oil mulls between KBr windows) were re-
corded on a Perkin Elmer M457 spectrometer.
As seen from Figs. 3a 3c, the initiation threshold
of the crystalline primers is independent of the wave-
length of the initiating light. However, it is neces-
sary to study the influence of the particle size distri-
bution and the type of interparticle cohesion on initia-
tion of these explosives. Laser initiation of the com-
plexes was performed with assistance of V.V. Blago-
veshchenskii.
The UV spectra were recorded on a Perkin Elmer
LAMBDA 40 spectrometer in 1-cm quartz cells (anal-
ytical concentration 10 10 M).
1
2
1
The H NMR spectra were recorded on a Bruker
AC (300 MHz) spectrometer using DMSO-d6 as
solvent and hexamethyldisiloxane (HMDS) as internal
reference.
Thus, the (tetraminetetrazolato)cobalt(III) perchlo-
rates can be used as primers both in conventional
Synthesis of I VII was monitored by thin-layer
chromatography on Silufol UV-254 plates, using 3%
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HIGH-ENERGY-CAPACITY COBALT(III) TETRAZOLATES
575
sodium perchlorate as eluent. A thermal gravimetric
analysis was performed on an MOM derivatograph
(Hungary) in the range 20 500 C at a heating rate
5-aminotetrazole [19], and 1,5-diaminotetrazole [20].
The physicochemical properties of the compounds
agreed with published data.
1
of 5 deg min . The onset temperature of intense de-
Tetramminebis(trazolato)cobalt(III) perchlorate
II, tetramminebis(5-methyltetrazolato)cobalt(III)
perchlorate III, tetramminebis(5-aminotetrazolato)-
cobalt(III) perchlorate IV, tetrammine-5-nitro-
aminotetrazolatocobalt(III) perchlorate V, and te-
tramminebis(1,5-diaminotetrazole)cobalt(III) per-
chlorate VI. Carbonatotetramminecobalt(III) perchlo-
rate (0.5 g) prepared by the procedure described in
[21] was dissolved in 5% perchloric acid (15 ml) until
CO2 evolution stopped. The solution was filtered.
An appropriate tetrazole derivative was added in 60%
excess to the filtrate. The reaction mixture was heated
on a boiling water bath for 4 h, cooled to 15 C, and
poured into propan-2-ol (100 ml). The precipitate was
filtered off and washed with two portions of ethanol
(2 5 ml). Yield (60 65 %). Compound II. IR spec-
composition, Toid, was determined on a thermograph
at a heating rate of 5.3 deg min . The sensitivity to
1
shock was determined by the pile-driving procedure
performed in accordance with GOST (State Standard)
1944 80. The minimal primer charge (MPC) of the
complexes was determined with respect to hexogen
in the geometry of detonating cap (DC) no. 8 (com-
paction pressures Pc of the compound and hexogen
2
were 121 and 363 kg cm , respectively).
The optical properties of the solid compounds were
studied on SPEFOT spectrophotometric unit described
in [13].
Diaquatetramminecobalt(III) perchlorate VIII pre-
pared by the procedure described in [14] was used in
further synthesis without isolation from the solutions.
1
trum, cm : 3320 m, 1329 m (NH3, Tz), 3050 m (CH),
1094 ws (ClO4). UV spectrum,
= 454 nm,
max
1
1
= 87 l cm 1 mol . H NMR spectrum (DMSO-d6),
, ppm: 4.00, 4.25 (9H, NH3 eq.), 3.66, 3.85 (3H,
NH3 ax.), 6.90 (H, C H, Tz ax.), 8.70 (H, C H,
Tz, eq.).
Tetramminebis(5-nitrotetrazolato)cobalt(III) per-
chlorate I and tetramminebis(1-methyl-5-aminote-
trazole)cobalt(III) perchlorate VII were prepared by
the procedure described in [15] in 54 and 51% yields,
1
respectively. Compound I. IR spectrum, cm : 1588 m,
1316 m (NH3, Tz), 1076 m (ClO4), 1540 m (NO2).
Found, %: C 6.7, H 4.1, N 45.7.
C2H14ClCoN12O4.
1
UV spectrum,
= 456 nm, = 74 l cm 1 mol .
max
1H NMR spectrum (DMSO-d6), , ppm: 3.79, 4.29
Calculated, %: C 6.6, H 3.9, N 46.1.
(12H, NH3).
1
Compound III. IR spectrum, cm : 3315 m, 1330 m
Found, %: C 4.8, H 2.3, N 42.6.
C2H12ClCoN14O8.
(NH3, Tz), 1101 s (ClO4), 1450 s, 1370 s (CH3).
1
UV spectrum,
= 455 nm, = 92 l cm 1 mol .
max
1H NMR spectrum (DMSO-d6), , ppm: 3.74, (12H,
Calculated, %: C 5.3, H 2.7, N 43.1.
NH3 eq.), 2.52 (6H, CH3 Tz ax.).
1
Compound VII. IR spectrum, cm : 3316 m,
Found, %: C 6.7, H 4.1, N 45.7.
C4H18ClCoN12O4.
1334 m (NH3, Tz), 1118 m (ClO4), 1628 m (C=N),
3236 w, 1616 w (NH2), 2830 w (CH3). UV spec-
1
1
trum,
= 466 nm, = 77 l cm 1 mol . H NMR
max
Calculated, %: C 6.6, H 3.9, N 46.1.
spectrum (DMSO-d6), , ppm: 3.85, 3.90 (9H,
NH3 eq.); 3.75, 3.80 (3H, NH3 ax.); 7.12 (2H,
NH2 Tz, ax.), 7.52 (2H, NH2 Tz eq.); 4.03 (3H,
CH3 Tz ax.), 4.22 (3H, CH3 Tz eq.).
1
Compound IV. IR spectrum, cm : 3318 m, 1312 m
(NH3, Tz), 3426 w, 1596 w (NH2) 1084 m (ClO4).
1
UV spectrum,
= 463 nm, = 80 l cm 1 mol .
max
1H NMR spectrum (DMSO-d6), , ppm: 4.05, 4.25
(9H, NH3 eq.), 3.45, 3.72 (3H, NH3 ax.), 5.22 (2H,
NH2 Tz ax.), 6.87 (2H, NH2 Tz, eq.).
Found, %: C 7.8, H 3.3, N 31.9.
C4H22Cl3CoN14O12.
Calculated, %: C 7.7, H 3.6, N 31.5.
Found, %: C 6.1, H 4.3, N 49.5.
C2H16ClCoN14O4.
Published procedures were used to prepare tetrazole
[16], 5-methyltetrazole [17], 5-nitroaminotetrazole [18],
Calculated, %: C 6.1, H 4.1, N 49.7.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 76 No. 4 2003

576
ZHILIN et al.
1
Compound V. IR spectrum, cm : 3320 s,
6. Kukushkin, Yu.N., Budanova, V.F., and Sedova, G.N.,
Termicheskoe prevrashchenie koordinatsionnykh so-
edinenii v tverdoi faze (Thermal Transformations of
Coordination Compounds in the Solid Phase), Lenin-
grad: Leningr. Gos. Univ., 1981.
7. Fronabarger, J., Schuman, A., Chapman, R.D., et al.,
AIAA Pap., 1995, no. 2858, pp. 1 7.
1308 m (NH3, Tz), 1556 m (NO2), 1340 m (C N),
1110 s (ClO4). UV spectrum,
= 475 nm,
=
max
63 l cm 1 mol . 1H NMR spectrum (DMSO-d6),
, ppm: 4.10, 4.50 (6H, NH3 eq.), 3.45, 3.75 (6H,
NH3 ax.).
1
8. Sheng, D., Ma, F., Sun, F., and Lu, Q., Hanneng
caliliao=Energ. Mater., 2000, vol. 8, no. 3,
pp. 100 103.
Found, %: C 3.8, H 3.9, N 39.6.
CH12ClCoN10O6.
9. Moore, D.S. and Robinson, S.D., Adv. Inorg. Chem.,
Calculated, %: C 3.4, H 3.4, N 39.5.
1988, vol. 32, pp. 171 239.
10. Subba Rao, N.S.V., Ganorkar, M.C., Mohan Mura-
li, B.K., and Ramaswamy, C.P., Bull. Acad. Polon.
Sci., 1979, vol. 27, no. 1, pp. 21 28.
11. Shilin, A.Yu., Ilyushin, M.A., Tselinskii, I.V., et al.,
Zh. Prikl. Khim., 2002, vol. 75, no. 11, pp. 1885 1888.
12. Morosin, B., Dunn, R.G., Assink, R., et al., Acta
Crystallogr., 1997, Sect. C, vol. 53, pp. 1609 1611.
13. RF Patent no. 1673928.
1
Compound VI. IR spectrum, cm : 3321 m,
1332 m (NH3, Tz), 1095 s (ClO4), 1630 m (C=N),
3232 w, 1610 w (NH2). UV spectrum, max = 470 nm
= 80 l cm 1 mol . H NMR spectrum (DMSO-d6),
, ppm: 4.00, 4.15 (9H, NH3 eq.), 3.70, 3.78
(3H, NH3 ax.), 6.20 [4H, (NH2)2 Tz ax.], 6.92
[4H, (NH2)2 Tz, eq.).
1
1
14. Ilyushin, M.A., Lukogorskaya, A.S., Tselinskii, I.V.,
and Brykov, A.S., Zh. Obshch. Khim., 1999, vol. 69,
no. 3, pp. 449 451.
15. Zhilin, A.Yu., Ilyushin, M.A., Tselinskii, I.V., and
Brykov, A.S., Zh. Prikl. Khim., 2001, vol. 74, no. 1,
pp. 96 99.
Found, %: C 3.8, H 3.6, N 35.9.
C2H20Cl3CoN16O12.
Calculated, %: C 3.8, H 3.2, N 35.8.
16. Gaponik, P.N. and Karavai, V.P., Vestn. Belorus. Gos.
Univ., Ser. 2, (Minsk), 1980, no. 3, pp. 51 52.
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