Energetic bis(3,5-dinitro-1 H -1,2,4-triazolyl)dihydro- and dichloroborates and bis(5-nitro-2 H -tetrazolyl)-, bis(5-(trinitromethyl)-2 H -tetrazolyl)-, and bis(5-(fluorodinitromethyl)-2 H -tetrazolyl)dihydroborate

Article abstract of DOI:10.1021/ic400504h

Salts of bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydro- and dichloroborate and bis(5-nitro-2H-tetrazolyl)-, bis(5-trinitromethyl-2H-tetrazolyl)-, and bis(5-fluorodinitromethyl-2H-tetrazolyl)dihydroborate anions have been synthesized by the treatment of hydroborates or chloroborates with the corresponding nitroazoles or nitroazolates, respectively. Alkali-metal salts of these dihydroborates are energetic and can be shock-sensitive, while salts with larger organic cations, such as NMe₄⁺, PPh ₄⁺, or (Ph₃P)₂N⁺, are less sensitive. Poly(nitroazolyl)borates are promising candidates for a new class of environmentally benign energetic materials and high-oxygen carriers.

Full text of DOI:10.1021/ic400504h

Article
pubs.acs.org/IC
Energetic Bis(3,5-dinitro‑1H‑1,2,4-triazolyl)dihydro- and
dichloroborates and Bis(5-nitro‑2H‑tetrazolyl)‑, Bis(5-
(
trinitromethyl)‑2H‑tetrazolyl)‑, and Bis(5-
(
fluorodinitromethyl)‑2H‑tetrazolyl)dihydroborate
Ralf Haiges,* C. Bigler Jones, and Karl O. Christe*
Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, California
0089-1661, United States
9
*
S Supporting Information
ABSTRACT: Salts of bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydro- and dichloroborate and bis(5-nitro-2H-tetrazolyl)-, bis(5-
trinitromethyl-2H-tetrazolyl)-, and bis(5-fluorodinitromethyl-2H-tetrazolyl)dihydroborate anions have been synthesized by the
treatment of hydroborates or chloroborates with the corresponding nitroazoles or nitroazolates, respectively. Alkali-metal salts of
+
+
these dihydroborates are energetic and can be shock-sensitive, while salts with larger organic cations, such as NMe , PPh , or
4
4
+
(
Ph P) N , are less sensitive. Poly(nitroazolyl)borates are promising candidates for a new class of environmentally benign
3 2
energetic materials and high-oxygen carriers.
INTRODUCTION
polyazolylborates with nitro-group-containing azoles have not
been explored so far.
■
The development of environmentally benign, nontoxic “green”
energetic materials has received a great deal of attention in
1
EXPERIMENTAL SECTION
recent years. 1,2,4-Triazoles and tetrazoles are readily
■
Caution! Most compounds of this study are energetic materials that can
explode under certain conditions (e.g., elevated temperatures, impact,
friction, or electric discharge). Although no difficulties were encountered
during the course of this work, appropriate safety precautions such as the
use of shields or barricades in a fume hood and personal protection
equipment (safety glasses, face shields, ear plugs, as well as gloves and suits
made from leather and/or Kevlar) should be taken all of the time when
handling these materials. Ignoring safety precautions may lead to serious
injuries!
accessible nitrogen-rich, energetic compounds whose usefulness
as energetic materials can be further increased by the
introduction of nitro functionalities. While poly(azolyl)borates
2
−21
22,23
derived from pyrazoles
and triazoles
are commonly
used ligands in coordination and organometallic and bio-
inorganic chemistry, the chemistry of tetrazolylborates is much
less developed. Although a series of tetrazolyldihydroborates
such as bis(5-H-tetrazolyl)dihydroborate,
aminotetrazolyl)dihydroborate,
2
4−28
bis(5-
bis(1-methyl-5-
and tris(tetrazolyl)-
2
9
Materials and Apparatus. All reactions were carried out in Pyrex
glass ampules that were closed by Teflon valves (Kontes or J. Young).
Volatile materials were handled in a Pyrex glass vacuum line.
Nonvolatile materials were handled in the dry argon atmosphere of
a glovebox. NMR spectra were recorded at 298 K on a Bruker
AMX500 or a Varian VNMRS-600s spectrometer using a (CD ) CO
3
0
thiotetrazolyl)dihydroborate,
3
1
hydroborate have been reported, these compounds did not
contain the necessary oxidizing substituents for rendering them
highly energetic materials. These shortcomings can be
overcome by the introduction of nitro groups. Poly-
3
2
or a CD
are given relative to neat tetramethylsilane ( H and C), BF ·Et O
CN solution in standard 5 mm glass tubes. Chemical shifts
3
1
13
(
dinitrotriazolyl)- and poly(nitrotetrazolyl)borates are expected
3
2
to have high potential for green energetic materials applications
because of their high nitrogen and oxygen contents. However,
to the best of our knowledge, the syntheses and properties of
Received: February 27, 2013
Published: April 24, 2013
©
2013 American Chemical Society
5551
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
(11
B), neat CH NO ( N), CFCl ( F), or 85% H PO ( P). Raman
14
19
31
g; H2 evolved, 3.8 mmol; DTA decomposition onset, 104 °C
(explosion). Raman (100 mW): ν(rel intens) 3004 (3.9), 2955 (9.0),
2931 (7.8), 2904 (7.6), 2878 (4.8), 2853 (7.8), 2833 (7.6), 2727 (1.3),
2512 (1.2), 2469 (2.9), 1623 (1.9), 1611 (1.6), 1604 (1.6), 1465 (6.3),
1383 (2.6), 1369 (1.7), 1359 (1.8), 1352 (1.7), 1308 (2.0), 1300 (2.1),
1287 (2.6), 1249 (1.2), 1218 (1.0), 1182 (1.2), 1162 (1.2), 1156 (1.1),
1127 (1.4), 1118 (1.3), 1103 (0.9), 1056 (1.6), 1022 (1.2), 990 (4.3),
964 (2.9), 957 (2.8), 866 (3.5), 845 (10.0), 802 (1.0), 741 (0.7), 687
(0.8), 654 (0.9), 572 (0.7), 410 (2.6), 410 (2.6), 403 (2.8), 365 (6.5),
3
2
3
3
4
spectra were recorded at ambient temperatures in Pyrex glass tubes in
the range of 4000−80 cm on a Bruker Equinox 55 FT-RA
spectrometer using a Nd:YAG laser at 1064 nm. IR spectra were
recorded in the range 4000−400 cm on a Midac, an M Series, or a
Bruker Optics Alpha Fourier transform infrared spectrometer using
KBr pellets. The pellets were prepared very carefully using an Econo
mini-press (Barnes Engineering Co.). Differential thermal analysis
−1
−
1
(
DTA) curves were recorded with a purge of dry nitrogen gas on an
−1
OZM Research DTA552-Ex instrument with Meavy 2.2.0 software.
The heating rate was 5 °C/min, and the sample size was 3−15 mg.
The impact and friction sensitivity data were determined on OZM
Research BAM Fall Hammer BFH-10 and OZM Research BAM
Friction FSKM-10 apparatuses, respectively, through five individual
measurements that were averaged. Both instruments were calibrated
using RDX. The starting materials LiBH , NaBH , KBH , NMe BH ,
347 (7.0), 290 (1.5), 269 (1.5), 259 (1.5), 209 (2.5) cm .
[Na(C H O ) ][BH (FDNTz) ] (Na[4], where FDNTz = 5-(fluoro-
4
10 2 3
2
2
dinitromethyl)-2H-tetrazolyl): 1.447 g; weight expected for 2.00
mmol, 1.356 g; H
evolved, 3.7 mmol; DTA decomposition onset, 148
2
°C (explosion).
Preparation of the NMe
+, PPh +, and (Ph N+ Salts of Anions
P)
3 2
4
4
1
−4. A solution of NMe Cl, PPh Cl, or (Ph P) NCl (1.10 mmol) in
4
4
3
2
4
4
4
4
4
3
0 mL of water and 10 mL of ethanol was added to a solution of the
PPh Cl, and (Ph P) NCl (all Aldrich) were used without further
4
3
2
corresponding sodium bis(azolyl)dihydroborates Na[1]−Na[4] (1.00
mmol) in 20 mL of water. Immediately, an off-white to pale-yellow
precipitate formed. The precipitated was filtered off, washed with
water, and dried in air. Single crystals were obtained by
recrystallization from acetone/water or acetonitrile/water solutions.
NMe [BH (DNT) ] (TMA[1], where TMA = Tetramethylammo-
purification. Boron trichloride (Aldrich) was freshly purified by
fractional condensation prior to use. Solvents were dried by standard
methods and freshly distilled prior to use. PPh BH and (Ph P) NBH
4
4
4
3
2
were prepared according to literature procedures from NaBH and
4
32−34
PPh Cl or (Ph P) NCl, respectively.
Sodium 3,5-dinitro-1H-
4
3
2
3
5
1
,2,4-triazolate,3 3,5-dinitro-1H-1,2,4-triazole (HDNT), 5-nitrotetra-
4
2
2
6
37−39
nium): DTA decomposition onset, 157 °C. NMR (CD CN, 298 K):
3
1 11 1 11 1
zole (HNTz), 5-(trinitromethyl)tetrazole (HTNTz),
and 5-
40
H, δ 3.20 (NCH ), 3.9 (br, BH ); B, δ −6.2 (t, J( B H) = 96.4
(
fluorodinitromethyl)tetrazole (HFDNTz) were prepared according
3
2
Hz); 13C, δ 56.3 (t, J( C N) = 4.2 Hz, NCH ); N, δ −22.6 (τ
1
13 14
14
=
to literature procedures.
3
1/2
5
0 Hz, NO ), −26.6 (τ = 50 Hz, NO ), −29.6 (τ = 50 Hz, NO ),
Preparation of Sodium Dihydroborates Na[1]−Na[4]. Stoichio-
metric amounts of sodium borohydride (2.00 mmol) and the
corresponding nitroazole (4.00 mmol) were loaded into a 100 mL
glass ampule that was equipped with a Teflon-coated stir bar. The
ampule was evacuated, and about 10 mL of anhydrous dimethoxy-
ethane (DME) was condensed into the ampule at −196 °C. The
ampule was closed, and the reaction mixture was allowed to warm to
ambient temperature. After hydrogen-gas evolution had seized, the
obtained pale-yellow to light-orange reaction mixture was stirred for 4
h at ambient temperature. The reaction mixture was cooled to −196
2
1/2
2
1/2
2
−
74 (τ = 350 Hz, C N ), −337.3 (τ = 6 Hz, NCH ). Raman (200
1/2
2
3
1/2
3
mW): ν(rel intens) 3043 (1.3), 2984 (2.1), 2958 (0.8), 2927 (1.4),
2
1
896 (0.3), 2823 (0.5), 2530 (0.3), 2478 (0.7), 1558 (1.1), 1505 (0.4),
449 (1.5), 1424 (10.0), 1393 (1.5), 1379 (2.4), 1371 (2.6), 1331
(
(
(
0.8), 1314 (0.8), 1312 (0.7), 1198 (0.9), 1191 (1.1), 1180 (0.9), 1153
0.3), 1115 (0.5), 1110 (0.4), 1102 (0.4), 1025 (0.9), 1003 (0.1), 954
0.2), 830 (0.2), 771 (0.1), 766 (0.1), 755 (0.3), 498 (0.3), 473 (0.3),
4
55 (0.3), 369 (0.5), 355 (0.6), 336 (0.6), 299 (0.7), 259 (0.4), 223
−1
(0.5), 174 (0.8), 151 (0.9), 96 (3.0), 92 (3.0), 85 (3.8) cm . IR
(KBr): ν 3040 vw, 2968 vw, 2925 vw, 2874 vw, 2867 vw, 2528 m, 2477
°
C and the amount of evolved hydrogen determined by pressure and
temperature in calibrated volume segments of a glass vacuum line.
Na(C H O ) ][BH (DNT) ] (Na[1], where DNT = 3,5-dinitro-1H-
m, 1569 vs, 1545 s, 1507 s, 1485 vs, 1450 vw, 1417 m, 1379 m, 1332 s,
1
315 m, 1301 m, 1287 w, 1198 w, 1190 m, 1180 m, 1153 m, 1110 m,
[
4
10 2 3
2
2
1
,2,4-triazolyl): 1.331 g; weight expected for 2.00 mmol, 1.223 g; H
1039 w, 953 s, 898 w, 886 m, 850 s, 843 s, 827 s, 773 w, 770 w, 720 w,
694 vw, 654 m, 604 vw, 496 vw, 474 vw, 461 vw, 459 w, 456 w, 420 w,
2
evolved, 4.1 mmol; DTA decomposition onset, 150 °C. NMR
1
−1
(
acetone-d , 298 K): H, δ 3.27 (CH O), 3.46 (OCH ), 3.8 (br,
404 w cm .
6
3
2
11
1
11
1
13
BH ); B, δ −6.1 (t, J( B H) = 93.3 Hz); C, δ 58.8 (CH O), 77.4
[(Ph
3
P)
2 2 2
N][BH (DNT) ] (PPN[1], where PPN = Bis-
2
3
14
(triphenylphosphoranylidene)ammonium): DTA decomposition
(
OCH ); N, δ −27.3 (τ = 60 Hz, NO ), −29.9 (τ = 60 Hz,
2
1/2
2
1/2
1
onset, 178 °C. NMR (acetone-d , 298 K): H, δ 3.9 (br, BH ), 7.5−
NO ), −70 (τ = 500 Hz, C N ). Raman (100 mW): ν(rel intens)
6
2
2
1/2
2
3
11
1
11
1
13
7
.8 (C H P); B, δ −6.1 (t, J( B H) = 91.3 Hz); C, δ 128.2 (d,
13 31
3
2
2
005 (1.3), 2990 (1.0), 2954 (2.7), 2933 (2.3), 2925 (2.3), 2909 (2.3),
877 (1.5), 2858 (2.3), 2853 (2.1), 2836 (2.3), 2799 (0.6), 2795 (0.6),
729 (0.4), 1558 (1.2), 1508 (0.6), 1477 (1.0), 1427 (10.0), 1379
6
5
1
J( C P) = 107.0 Hz), 130.23, 130.28, 130.33, 133.11, 133.15,
14
133.20, 134.5 (PC
NO ), −29.7 (τ1/2 = 50 Hz, NO
(τ1/2 = 500 Hz, C
H
), 159.9 (CNO
), −89 (τ1/2 = 500 Hz, C
); P{ H}, δ 21.9 (PC ). Raman (200 mW):
); N, δ −27.8 (τ1/2 = 70 Hz,
6
5
2
(
(
(
3.3), 1332 (1.0), 1318 (0.8), 1303 (0.4), 1287 (0.6), 1251 (0.4), 1199
2.3), 1167 (0.4), 1156 (0.4), 1120 (0.8), 1105 (0.6), 1026 (1.7), 867
1.2), 831 (1.3), 775 (0.6), 766 (0.4), 503 (0.4), 304 (0.6), 252 (0.4),
2
2
N
2 3
), −120
31
1
N
H
6 5
2
3
ν(rel intens) 3177 (0.4), 3149 (0.8), 3063 (10.0), 3028 (0.8), 3014
(1.2), 2995 (0.8), 2958 (0.4), 2511 (0.4), 2470 (0.8), 1591 (4.2), 1577
(1.5), 1567 (0.8), 1555 (0.8), 1529 (0.4), 1505 (0.4), 1483 (0.4), 1428
(6.5), 1390 (4.6), 1366 (2.7), 1343 (0.8), 1332 (0.8), 1321 (0.8), 1283
(0.4), 1198 (1.5), 1185 (1.2), 1165 (1.2), 1112 (2.7), 1100 (1.9), 1029
(3.5), 1002 (7.7), 830 (1.5), 775 (0.4), 767 (0.8), 725 (0.4), 665 (2.3),
618 (1.9), 547 (0.4), 540 (0.4), 528 (0.4), 498 (0.4), 476 (0.4), 462
(0.4), 442 (0.4), 430 (0.4), 397 (0.4), 359 (1.2), 336 (0.8), 319 (0.8),
282 (1.2), 266 (1.5), 257 (1.5), 242 (1.9), 233 (1.9), 201 (1.2), 178
226 (0.6), 170 (1.2), 161 (1.0), 133 (1.5), 85 (3.7), 2464 (1.0), 2468
(
(
2
0.8), 2473 (0.8), 2473 (0.8), 2494 (0.4), 338 (0.8), 356 (0.8), 362
−1
0.8), 367 (0.8) cm . IR (KBr): ν 2997 vw, 2940 w, 2902 w, 2832 w,
748 vw, 2498 m sh, 2479 m, 2158 w, 1570 vs, 1511 vs, 1474 w, 1458
w, 1420 m, 1373 m, 1328 s, 1320 s, 1247 w, 1192 m, 1150 m, 1122 m,
1
6
106 m, 1086 s, 1031 w, 984 vw, 889 w, 854 s, 828 m, 771 w, 720 w,
−1
52 m, 469 vw cm .
Na(C H O ) ][BH (NTz) ] (Na[2], where NTz = 5-nitro-2H-
[
4
10 2 3
2
2
−1
tetrazolyl): 0.987 g; weight expected for 2.00 mmol, 1.048 g; H
(1.2), 161 (1.5), 93 (11.5) cm . IR (KBr): ν 3080 vw, 3060 w, 2507
w, 2468 m, 1589 w, 1559 vs, 1535 m, 1504 s, 1482 m, 1439 s, 1417 w,
1407 w, 1375 w, 1365 w, 1320 s, 1313 s, 1303 s, 1288 s, 1270 m, 1184
w, 1161 w, 1150 w, 1116 vs, 1104 m, 1097 m, 1026 vw, 997 vw, 893
vw, 850 w, 839 vw, 825 w, 796 vw, 753 w, 745 w, 724 s, 693 s, 650 vw,
2
evolved, 3.9 mmol; DTA decomposition onset, 169 °C (explosion).
Raman (100 mW): ν(rel intens) 3006 (3.2), 2992 (3.2), 2953 (5.1),
2
2
929 (4.8), 2904 (4.1), 2880 (3.0), 2852 (4.8), 2833 (4.8), 2725 (0.8),
523 (1.1), 2467 (2.7), 1561 (1.6), 1465 (4.2), 1419 (10.0), 1383
−1
(
(
(
3
1.4), 1320 (3.2), 1291 (1.2), 1229 (0.9), 1222 (1.1), 1172 (1.4), 1152
2.9), 1112 (1.2), 1072 (1.0), 1035 (4.4), 970 (0.8), 864 (1.9), 840
1.6), 775 (1.3), 734 (2.5), 538 (1.0), 459 (1.0), 383 (1.6), 373 (1.4),
616 vw, 598 vw, 546 m, 534 s, 501 m, 457 vw cm .
[PPh ][BH (NTz) ] (TPP[2], Where TPP = Tetraphenylphospho-
4
2
2
nium): DTA decomposition onset, 168 °C; 276 mg. NMR (acetone-
−1
1
1
1
11
20 (1.3), 292 (1.7) cm .
Na(C H O ) ][BH (TNTz) ] (Na[3], where TNTz = 5-(trinitro-
d , 298 K): H, δ 4.1 (br q, J( H B) = 115 Hz, BH ), 7.8−8.1
6
2
11
1
11
1
13
[
(C H ); B, δ −5.5 (t, J( B H) = 110.2 Hz); C, δ 118.9 (d,
6 5
13 31 2 13 31
4
10 2 3
2
2
1
methyl)-2H-tetrazolyl): 1.621 g; weight expected for 2.00 mmol, 1.464
J( C P) = 90.5 Hz), 131.3 (d, J( C P) = 13.2 Hz), 135.6 (d,
5
552
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
Scheme 1. Synthesis of Bis(nitroazolyl)dihydroborate Anions 1−4
3
13 31
14
11
1
11 1
J( C P) = 11.2 Hz), 136.3 (PC H ); N, δ −29.1 (τ1/2 = 50 Hz,
98 Hz, BH ), 7.8−8.1 (C H ); B, δ −5.8 (t, J( B H) = 92.4 Hz);
6
5
1
2
6
5
3
1
13
1
1
13 19
NO ), −67 (τ = 370 Hz, CN ); P{ H}, δ 23.9 (PC H ). Raman
C, δ 118.1 (br d, J( C F) = 278 Hz, CF(NO ) ), 118.9 (d,
2 2
J( C P) = 89.7 Hz), 131.3 (d, J( C P) = 13.2 Hz), 135.6 (d,
J( C P) = 10.0 Hz), 136.3 (d, J( C P) = 3.2 Hz, PC H ), 153.9
2
1/2
4
6
5
13 31
2
13 31
(
(
(
(
(
(
200 mW): ν(rel intens) 3175 (0.6), 3148 (0.7), 3067 (10.0), 3014
0.7), 2998 (0.6), 2961 (0.5), 2530 (0.4), 2474 (1.0), 1589 (4.5), 1578
1.7), 1551 (1.0), 1487 (0.4), 1461 (2.6), 1440 (0.6), 1414 (6.3), 1342
0.3), 1317 (0.7), 1224 (0.5), 1190 (1.1), 1167 (1.2), 1150 (1.8), 1133
0.7), 1112 (1.5), 1101 (2.6), 1068 (0.6), 1036 (4.5), 1029 (4.1), 1002
9.1), 987 (0.6), 974 (0.6), 934 (0.3), 838 (0.8), 775 (0.5), 729 (0.5),
3
13 31
3
13 31
6
5
2
13 19
14
(
−
(
d, J( C F) = 24.8 Hz, CN ); N, δ −23.2 (τ = 50 Hz, NO ),
4
1/2
2
1
9
24.9 (τ1/2 = 50 Hz, NO ), −64 (τ = 400 Hz, CN ); F, δ −95.8
2
1/2
4
31 1
CF(NO ) ); P{ H}, δ 23.6 (PC H ). Raman (200 mW): ν(rel
2
2
6
5
intens) 3175 (0.7), 3147 (0.7), 3074 (9.6), 3015 (0.9), 2999 (0.9),
6
(
82 (1.8), 618 (1.8), 538 (0.4), 457 (0.4), 445 (0.4), 398 (0.3), 316
0.6), 296 (1.1), 257 (2.8), 201 (2.6) cm . IR (KBr): ν 3092 vw, 3063
2
1
1
1
8
964 (0.7), 2514 (0.7), 2474 (1.1), 1589 (6.2), 1579 (2.0), 1491 (1.6),
445 (0.7), 1394 (0.7), 1361 (1.1), 1358 (1.1), 1354 (0.9), 1345 (0.9),
316 (0.9), 1215 (0.9), 1193 (1.3), 1170 (1.6), 1110 (1.6), 1101 (2.7),
056 (1.3), 1030 (5.3), 1003 (10.0), 985 (1.6), 971 (1.1), 944 (1.1),
37 (2.2), 803 (0.7), 757 (0.7), 727 (0.9), 682 (2.4), 618 (2.0), 550
−1
w, 2959 vw, 2905 vw, 2511 w, 2470 w, 1609 vs, 1485 m, 1442 s, 1438
s, 1394 w, 1356 w, 1341 w, 1310 m, 1238 m, 1226 m, 1191 w, 1169 w,
1
s, 800 m, 753 m, 724 s, 690 s, 639 w, 616 vw, 591 vw, 527 vs, 463 vw
cm .
PPh ][BH (TNTz) ] (TPP[3]): DTA decomposition onset, 107 °C
139 m, 1110 s, 1088 w, 1043 m, 1028 w, 998 m, 978 m, 857 vw, 835
(
0.7), 424 (1.1), 369 (2.0), 331 (0.9), 286 (2.0), 253 (4.9), 202 (2.9),
−1
−1
182 (1.8) cm . IR (KBr): ν 3093 vw, 3062 vw, 2902 vw, 2510 w, 2469
w, 1609 vs, 1485 m, 1442 s, 1438 s, 1393 w, 1358 w, 1341 w, 1310 m,
1233 m, 1228 m, 1192 m, 1169 m, 1139 m, 1110 s, 1088 m, 1043 m,
1028 w, 998 m, 978 m, 857 vw, 835 s, 800 s, 754 m, 724 s, 690 s, 667
[
4
2
2
1
1
1
11
(
explosion). NMR (acetone-d , 298 K): H, δ 4.1 (br q, J( H B) =
6
11
1
11 1
9
5 Hz, BH ), 7.8−8.1 (C H ); B, δ −5.5 (t, J( B H) = 90.5 Hz);
1 13 31 2 13 31
2
6
5
1
3
−1
C, δ 118.9 (d, J( C P) = 89.4 Hz), 131.3 (d, J( C P) = 13.1
m, 616 w, 528 vs cm .
3
13 31
3
13 31
Hz), 135.6 (d, J( C P) = 9.8 Hz), 136.3 (d, J( C P) = 3.3 Hz,
PC H ); N, δ −26.3 (τ = 40 Hz, NO ), −32.6 (τ = 50 Hz,
NO ); P{ H}, δ 23.8 (PC H ). Raman (200 mW): ν(rel intens)
Preparation of NMe BCl (DNT) (TMA[5]). A 25 mL glass ampule
equipped with a Teflon-coated stir bar was charged with NMe Cl
4
2
2
14
6
5
1/2
2
1/2
4
3
1
1
2
6
5
(0.110 g, 1.00 mmol) and sodium 3,5-dinitro-1H-1,2,4-triazolate
(0.362 g, 2.00 mmol). The ampule was cooled to −196 °C, and
acetonitrile (5 mL) and boron trichloride (0.117 g, 1.00 mmol) were
condensed in on a vacuum line. The closed ampule was allowed to
warm to ambient temperature. The milky mixture was stirred for 48 h.
The precipitate was filtered off. The filtrate was cooled to −20 °C and
the solvent slowly removed in a vacuum. TMA[5] was obtained as
pale-yellow crystals (397 mg; weight expected for 1.00 mmol, 0.472 g).
Raman (100 mW): ν(rel intens) 3044 (2.8), 2984 (4.8), 2960 (2.6),
2928 (2.9), 2896 (0.5), 2822 (1.2), 2775 (0.2), 1566 (1.2), 1513 (0.5),
1431 (10.0), 1404 (1.6), 1383 (5.8), 1334 (0.8), 1315 (2.9), 1182
(1.9), 1113 (1.4), 1024 (2.5), 951 (0.9), 917 (2.2), 853 (0.3), 832
(2.6), 815 (0.3), 773 (0.9), 764 (1.0), 755 (2.7), 656 (0.8), 516 (0.3),
480 (0.5), 457 (0.3), 392 (0.9), 370 (0.7), 352 (1.1), 322 (0.8), 309
3
174 (1.0), 3146 (1.0), 3073 (10.0), 3014 (1.0), 2964 (1.0), 2511
(
(
(
(
(
2
2
1
1
1.0), 2471 (1.0), 1620 (1.0), 1589 (5.0), 1453 (1.0), 1417 (1.0), 1387
1.0), 1377 (1.0), 1361 (1.0), 1343 (0.1), 1313 (1.0), 1286 (1.0), 1276
0.9), 1245 (0.3), 1222 (0.3), 1191 (1.0), 1171 (1.0), 1113 (1.0), 1101
2.0), 1059 (1.0), 1030 (4.0), 964 (1.0), 846 (2.0), 803 (0.4), 752
0.3), 729 (0.5), 682 (2.0), 618 (1.0), 369 (1.0), 354 (2.0), 329 (1.0),
95 (1.0), 284 (1.0), 201 (2.0) cm . IR (KBr): ν 3088 vw, 3058 w,
510 m, 2470 m, 1618 vs, 1609 vs, 1597 vs, 1485 m, 1442 s, 1437 s,
384 m, 1341 w, 1307 m, 1285 s, 1192 vw, 1171 w, 1139 m, 1110 s,
046 s, 998 m, 988 m, 856 w, 843 s, 801 vs, 759 m, 753 s, 724 vs, 690
−1
−1
s, 657 w, 615 w, 607 vw, 527 vs, 461 w, 449 w cm .
PPh ][BH (FDNTz) ] (TPP[4]): DTA decomposition onset, 152 °C
(
[
4
2
2
1
1
1
11
explosion). NMR (acetone-d , 298 K): H, δ 4.2 (br q, J( H B) =
6
5
553
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Scheme 2. Conversion of the Sodium Salts into the Corresponding NMe , PPh , and (Ph P) N Salts of the
Article
+
+
+
4
4
3
2
Bis(nitroazolyl)dihydroborates 1−4
Scheme 3. Synthesis of TMA[5]
+
(
7
0.8), 248 (1.0), 214 (0.7), 171 (1.7), 115 (4.1), 606 (0.2), 1123 (0.4),
98 (0.2), 228 (0.6) cm .
(Ph P) N salts of the anions 1−4 (Scheme 2), which were
3
2
−1
then characterized by their crystal structures. Because of the
energetic and potential explosive nature of these compounds,
no elemental analysis data were determined.
RESULTS AND DISCUSSION
■
The general strategy for the synthesis of azolylhydroborates
involves the reaction of an alkali-metal borohydride with the
corresponding azole. Such conversions are usually carried out
When LiBH was reacted with 2 equiv of HDNT in diethyl
4
ether and the solvent removed in a vacuum, the obtained pale-
yellow lithium bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydroborate
was found to be highly explosive and very sensitive to friction
and mechanical impact. A small sample (∼50 mg) of the
compound that had been stored inside a drybox exploded
violently without any provocation. Because of their high
sensitivity, the synthesis and characterization of any lithium
bis(dinitrotriazolyl)- and bis(nitrotetrazolyl)dihydroborate
were not pursued any further.
with the molten azole and typically involve reaction temper-
atures in excess of 140 °C. Substitution with NO groups
increases the acidity of an azole because of the strong electron-
withdrawing effect of the nitro group. Because of their
increased acidity, 3,5-dinitro-1H-1,2,4-triazole (HDNT), 5-
nitro-2H-tetrazole (HNTz), 5-(trinitromethyl)-2H-tetrazole
7
2
(
(
HTNTz), and 5-(fluorodinitromethyl)-2H-tetrazole
HFDNTz) already react in solution at ambient temperature
When solutions of NMe Cl, PPh Cl, and (Ph P) NCl in 10−
4 4 3 2
with alkali-metal borohydrides under evolution of hydrogen
25% ethanol in water were added to aqueous solutions of the
sodium salts of the dihydroborates 1−4, white precipitates of
the corresponding tetramethylammonium salts TMA[1]−
TMA[4], tetraphenylphosphonium salts TPP[1]−TPP[4],
and bis(triphenylphosphine)iminium salts PPN[1]−PPN[4],
respectively, formed (Scheme 2). Single crystals of TMA[1],
PPN[1], TPP[2], TPP[3], and TPP[4] were obtained by
recrystallization from acetone/water or acetonitrile/water.
The reaction of sodium 3,5-dinitro-1H-1,2,4-triazolate with
BCl and NMe Cl in acetonitrile was also explored as another
gas. The reaction of MBH (M = Na, Li) with 2 equiv of
4
HDNT, HNTz, HTNTz, and HFDNTz in DME at ambient
temperature resulted in the formation of colorless to pale-
yellow solutions of the corresponding bis(nitroazolyl)-
dihydroborates 1−4 according to Scheme 1. The quantitative
evolution of 2 equiv of hydrogen gas during these reactions was
confirmed by p, V, and T measurements. After evaporation of
the solvent in a vacuum, the DME adducts of the sodium
dihydroborates Na[1]−Na[4] were isolated in quantitative
yields as pale-yellow (nitrotetrazoles) to orange (dinitrotria-
zoles) solids. On one occasion, orange crystals of Na1 were
obtained when the solvent was removed from the reaction
mixture very slowly in a vacuum at ambient temperature.
The sodium dihydroborate DME adducts Na[1]−Na[4] are
energetic materials and, as such, should only be handled with
great care, although no difficulties were encountered during the
course of this work. The identity of the dihydroborates Na[1]−
Na[4] was established by their vibrational and multinuclear
NMR spectra and, in the case of Na[1], by its crystal structure.
In addition, the sodium dihydroborates Na[1]−Na[4] were
3
4
way for introducing 3,5-dinitro-1H-1,2,4-triazolyl ligands into a
borate anion (Scheme 3). When the reaction mixture was
filtered after 48 h, followed by evaporation of the solvent from
the filtrate, pale-yellow crystals of TMA[5] were obtained. The
identity of the compound was established by its crystal
structure.
The H, C{ H}, and P{ H} NMR spectra of the salts
containing the anions 1−4 showed the expected resonances for
DME, NMe , PPh , or (Ph P) N . In addition, the B NMR
1
13
1
31
1
+
4
+
4
+
11
3
2
spectra of the dihydroborate anions 1−4 showed broadened
triplet resonances with J( B H) coupling constants of 90−110
Hz, ranging from −6.2 to −5.5 ppm, which are similar to the
1
11 1
+
+
converted into the corresponding NMe , PPh , and
4
4
5
554
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
Table 1. Crystallographic Data and Structure Determination Details for Compounds Na[1], TMA[1], PPN[1], and TMA[5]
Na[1]
TMA[1]
PPN[1]
TMA[5]
formula
C H BN NaO
C H BN O
C H BN O P
C H BCl N O
8
1
6
32
10
14
8
14
11
8
40 33
11
8
12 12
2
11
mol wt [g/mol]
temp [K]
cryst syst
space group
a [Å]
622.31
100(2)
triclinic
403.11
100(2)
triclinic
867.52
472.00
100(2)
triclinic
140(2)
triclinic
P1
̅
P1
̅
P1
̅
9.9418(5)
P1
̅
11.1631(2)
12.6130(2)
12.6791(2)
110.9310(10)
105.0920(10)
104.7700(10)
1485.24(4)
2
11.4579(5)
12.0559(6)
13.0552(6)
85.815(2)
86.127(2)
79.409(2)
1765.24(14)
4
7.4547(19)
10.322(3)
12.988(3)
84.511(4)
78.393(4)
77.534(4)
954.5(4)
2
b [Å]
12.6744(6)
16.7980(8)
97.5665(7)
96.2596(7)
90.1580(7)
2053.12(17)
2
c [Å]
α [deg]
β [deg]
γ [deg]
V [Å3]
Z
ρcalc [g/cm3]
μ [mm−1]
F(000)
1.392
1.517
1.403
1.642
0.132
0.132
0.174
0.406
652
832
896
480
reflns collected
indep reflns
Rint
41074
10932
39853
5880
8675
7604
12196
4103
0.0453
0.0208
529
0.0253
0.0170
292
no. of param
R1 [I > 2σ(I)]
wR2 [I > 2σ(I)]
GOF
414
567
0.0324
0.0552
0.1407
1.039
0.0344
0.0580
0.1446
1.029
0.0866
0.0875
1.077
1.024
Figure 1. Crystal structures of the bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydro- and dichloroborate anions of Na[1] (A), TMA[1] (B), PPN[1] (C),
and TMA[5] (D). Thermal ellipsoids are drawn at the 50% probability level. Selected bond lengths (Å) and angles (deg): Na[1], B1−N1
1
1
.5756(12), B1−N6 1.5773(12), N1−B1−N6 106.74(7); TMA[1], B1−N1 1.586(3), B1−N4 1.577(3), N1−B1−N4 107.9(2); PPN[1], B1−N1
.5717(16), B1−N6 1.5821(15), N1−B1−N6 104.49(8); TMA[5], B1−N1 1.574(4), B1−N6 1.550(4), B1−Cl1 1.827(4), B1−Cl2 1.818(3), N1−
B1−N6 108.1(2), N1−B1−Cl1 107.1(2), N1−B1−Cl2 109.5(2), N6−B1−Cl1 110.9(2), N6−B1−Cl2 109.5(2).
5
555
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
Figure 2. Crystal structures of the bis(tetrazolyl)dihydroborate anions in TPP[2] (A), TPP[3] (B), and TPP[4] (C). Thermal ellipsoids are drawn
at the 50% probability level. Selected bond lengths (Å) and angles (deg): TPP[2], B1−N2 1.560(2), B1−N7 1.559(2), N2−B1−N7 106.00(12);
TPP[3], B1−N2 1.575(2), B1−N9 1.573(2), N2−B1−N9 105.27(11); TPP[4], B1−N3 1.572(3), B1−N8 1.626(8), N3−B1−N8 109.5(4).
values recently reported for potassium bis(tetrazolyl)-
of observed bond lengths and angles is given in the Supporting
Information.
Compound TPP[2] crystallizes in the monoclinic space
28
1
dihydroborate salts. The H chemical shifts of the BH2
groups were observed in the range of 3.8−4.2 ppm. The
vibrational spectra of the dihydroborate anions 1−4 showed
two well isolated but somewhat broadened bands for the
group P2 /c, while compounds TPP[3] and TPP[4] crystallize
1
̅
in the triclinic space group P1. The structures of the different
antisymmetric and symmetric BH stretching vibrations at
bis(tetrazolyl)dihydroborate anions in the crystal structures of
compounds TPP[2]−TPP[4] are depicted in Figure 2, and the
relevant crystallographic data and parameters are summarized
in Table 2.
2
−1
2
460−2480 and 2490−2530 cm , respectively.
X-ray Crystal Structures. The crystal structures of the
bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydroborate anions in Na-
[
1], TMA[1], and PPN[1] and the dichloroborate anion in
It is worth noting that all three bis(tetrazolyl)dihydroborate
anions contain B−N bonds to the nitrogen atom in the 2
position of the tetrazolyl ligand. This is in contrast to common
TMA[5] were determined. The relevant crystallographic data
and parameters are summarized in Table 1, and the molecular
structures of the bis(3,5-dinitro-1H-1,2,4-triazolyl)borate
anions are depicted in Figure 1. 4
24
tetrazolylborates such as bis(5H-tetrazolyl)dihydroborate, (5-
29
aminotetrazolyl)dihydroborate, and bis(5-methyltetrazolate)-
1
28
As expected for triazolylborates, all compounds contain B−
dihydroborate, which contain B−N bonds to the nitrogen
N bonds to the nitrogen atoms in the 2 position of the triazolyl
groups. The compounds Na[1], TMA[1], PPN[1], and
TMA[5] crystallize in the triclinic space group P1
structure of Na[1] consists of isolated [Na(DME) ] cation
units and borate anions. Because of coordination with three
DME molecules, the sodium atoms are well separated from the
triazolylborate anions. The crystals of TMA[1], PPN[1], and
TMA[5] contain well-separated cation and anion units.
Selected bond lengths and angles of the bis(3,5-dinitro-1H-
atom in the 1 position of the five-membered ring. The obtained
crystal structures of TPP[2] and TPP[4] suffer from a
positional disorder in one of the two tetrazolyl ligands of the
anion. In both cases, it was possible to model the disorder as a
superposition of two different orientations (ratio 60:40 in both
cases) of the five-membered ring and its substituents.
̅
+
3
Stability of the Compounds. The thermal stabilities of
the dihydroborates Na[1]−Na[4], TMA[1], PPN[1], and
TPP[2]−TPP[4] were determined using DTA scans with a
heating rate of 5 °C/min. The results of these scans are
summarized in Table 3. While the compounds Na[1],
TMA[1], and PPN[1] with bis(3,5-dinitro-1H-1,2,4-triazolyl)-
dihydroborate anions showed smooth decompositions in the
DTA scans at temperatures of 150 °C and above, all
investigated bis(nitrotetrazolyl)dihydroborates exploded upon
heating. The bis(5-trinitromethyltetrazolyl)dihydroborate
anion 2 is the thermally least stable anion among the
investigated tetrazolylborates with an explosion temperature
of 104−107 °C. The replacement of a nitro group of the
trinitromethyl moiety by a fluorine atom increases the thermal
stability. The explosion temperature of the resulting bis[5-
(fluorodinitromethyl)tetrazolyl]dihydroborate anion 4 was
1
,2,4-triazolyl)borates Na[1], TMA[1], PPN[1], and TMA[5]
are given in the caption of Figure 1. As expected, only small
changes in the structure of the bis(dinitrotriazolyl)-
dihydroborate anion 1 were observed between salts with
Na(DME) , NMe , or (Ph P) N counterions. The dihy-
droborate anion contains one short B−N bond of 1.572(2)−
1
The observed N−B−N bond angles vary between 104.49(8)°
and 107.9(2)°. The replacement of the two hydrogen atoms of
the borate anion with two chlorine atoms renders the B−N
bonds more covalent. The observed B−N bond lengths are
shortened to 1.550(4) and 1.574(4) Å, while the N−B−N
bond angle remains virtually unchanged [108.1(2)°]. A full list
+
3
+
4
+
3
2
.577(3) Å and a longer B−N bond of 1.577(1)−1.586(3) Å.
5
556
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
Table 2. Crystallographic Data and Structure Determination
Details for Compounds TPP[2]−TPP[4]
CONCLUSION
■
Poly(nitroazolyl)borates are promising candidates for a new
class of environmentally benign energetic materials. The
bis(3,5-dinitro-1H-1,2,4-triazolyl)dihydro- and dichloroborate
and bis(5-nitro-2H-tetrazolyl)-, bis(5-trinitromethyl-2H-tetra-
zolyl)-, and bis(5-fluorodinitromethyl-2H-tetrazolyl)-
dihydroborate anions have been synthesized and structurally+
characterized. Salts of these dihydroborates with [Na(DME)3]
counterions are energetic. The tetrazolyldihydroborate com-
pounds are friction- and impact-sensitive and explode upon
TPP[2]
TPP[3]
TPP[4]
formula
mol wt
C H BN O P
C H BN O P
C H BF N O P
2
6
22
10
4
28 22
14 12
28 22
2
12
8
580.31
788.38
734.36
[g/mol]
temp [K]
cryst syst
space group
a [Å]
100(2)
100(2)
triclinic
100(2)
triclinic
monoclinic
P2 /c
P1
̅
P1
̅
1
22.1054(10)
10.5458(5)
23.8276(11)
90
11.0434(7)
12.7349(8)
13.7231(9)
109.7350(10)
97.9540(10)
102.8410(10)
1722.62(19)
2
11.1504(6)
12.2645(6)
13.5087(7)
+
+
b [Å]
heating. Salts with larger organic cations such as NMe , PPh ,
4 4
+
c [Å]
or (Ph P) N are less sensitive. The present work demonstrates
3 2
α [deg]
β [deg]
γ [deg]
V [Å3]
Z
109.3580(10)
99.4140(10)
101.5770(10)
1653.72(15)
2
the general concept of synthesizing polyazolylborates contain-
ing highly oxidized nitroazolyl ligands by the treatment of
boronhydrides and -chlorides with the corresponding nitro-
azoles and sodium nitroazolates, respectively. The application
of this concept for the synthesis of higher substituted borates
such as tris(nitroazolyl)hydroborates and tetrakis(nitroazolyl)-
borates is currently being studied in our laboratories and will be
the subject of a forthcoming publication.
97.5540(10)
90
5506.5(4)
8
ρcalc [g/cm3] 1.400
1.520
1.475
μ [mm−1]
0.153
2400
0.164
0.163
F(000)
808
752
reflns
collected
129956
40440
40373
ASSOCIATED CONTENT
■
indep reflns
16662
0.0535
10098
0.0268
513
9869
*
S
Supporting Information
Rint
0.0216
517
X-ray crystallographic data in CIF format, Figures S1−S28, and
Tables S1−S52. This material is available free of charge via the
Internet at http://pubs.acs.org.
no. of param 828
R1 [I > 0.0412
σ(I)]
wR2 [I >
σ(I)]
GOF
0.0414
0.0580
2
0.0973
1.018
0.1066
1.023
0.1561
1.042
2
AUTHOR INFORMATION
■
*
Corresponding Author
E-mail: haiges@usc.edu (R.H.), kchriste@usc.edu (K.O.C.).
Table 3. Sensitivity Data of Compounds Na[1]−Na[4] and
TPP[2]−TPP[4]
Author Contributions
a
b
The manuscript was written through the contributions of all
authors.
Tdec
[°C]
Texplosion
[°C]
impact sensitivity
[J]
friction sensitivity
[N]
compound
Na[1]
150
19
36
>360
>360
>360
16
Notes
TMA[1]
PPN[1]
Na[2]
157
178
The authors declare no competing financial interest.
>100
8.0
169
ACKNOWLEDGMENTS
■
TPP[2]
Na[3]
168
104
107
148
152
25
40
This work was supported by the Office of Naval Research, the
Air Force Office of Scientific Research, the Defense Threat
Reduction Agency, and the National Science Foundation. We
appreciate NSF CRIF Grant 1048807 supporting an X-ray
diffractometer.
1.0
12
TPP[3]
Na[4]
1.5
40
2.5
16
TPP[4]
2.8
64
a
The impact sensitivity of RDX was found as 7.0 J on the instrument
b
used. The friction sensitivity of RDX was found as 160 N on the
REFERENCES
instrument used.
■
(
1) Talawar, M. B.; Sivabalan, R.; Mukundan, T.; Muthurajan, H.;
Sikder, A. K.; Gandhe, B. R.; Rao, A. S. J. Hazard. Mater. 2009, 161,
determined as 148−152 °C. The bis(5-nitrotetrazolyl)-
dihydroborates Na[4] and TPP[4] showed the highest thermal
stabilities with explosion temperatures of 168−169 °C. A
comparison of the explosion temperatures of compounds
Na[2]/TPP[2], Na[3]/TPP[3], and Na[4]/TPP[4] indicates
that the nature of the cation has only a marginal influence on
the thermal stability of the nitrotetrazolyldihydroborates.
The impact and friction sensitivities of the dihydroborates
Na[1]−Na[4], TMA[1], PPN[1], and TPP[2]−TPP[4] were
determined using a BAM Fall Hammer and a BAM Friction
Tester, respectively. The determined impact and friction
sensitivities of the dihydroborates Na[1]−Na[4], TMA[1],
PPN[1], and TPP[2]−TPP[4] are summarized in Table 3 and
show a trend similar the one observed for the thermal
stabilities.
5
(
8
89−607.
2) Jesson, J. P.; Trofimenko, S.; Eaton, D. R. J. Am. Chem. Soc. 1967,
9, 3148−3158.
(3) Reger, D. L.; Swift, C. A.; Lebioda, L. J. Am. Chem. Soc. 1983,
105, 5343−5347.
(4) Reger, D. L.; Mahtab, R.; Baxter, J. C.; Lebioda, L. Inorg. Chem.
1
(
2
(
986, 25, 2046−2048.
5) Reger, D. L.; Knox, S. J.; Lebioda, L. Organometallics 1990, 9,
218−2222.
6) Reger, D. L.; Knox, S. J.; Rheingold, A. L.; Haggerty, B. S.
Organometallics 1990, 9, 2581−2587.
(
(
(
7) Trofimenko, S. Chem. Rev. 1993, 93, 943−980.
8) Dias, H. V. R.; Gorden, J. D. Inorg. Chem. 1996, 35, 318−324.
9) Dias, H. V. R.; Jin, W. C.; Kim, H. J.; Lu, H. L. Inorg. Chem. 1996,
35, 2317−2328.
(10) Dias, H. V. R.; Kim, H. J. Organometallics 1996, 15, 5374−5379.
5
557
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558

Inorganic Chemistry
Article
(
11) Reger, D. L.; Pender, M. J.; Caulder, D. L.; Reger, L. B.;
Rheingold, A. L.; LiableSands, L. M. J. Organomet. Chem. 1996, 512,
9
(
(
1−96.
12) Templeton, J. L. J. Am. Chem. Soc. 2000, 122, 5670−5670.
13) Slugovc, C.; Padilla-Martinez, I.; Sirol, S.; Carmona, E. Coord.
Chem. Rev. 2001, 213, 129−157.
14) Dias, H. V. R.; Fianchini, M. Comments Inorg. Chem. 2007, 28,
3−92.
15) Dias, H. V. R.; Gamage, C. S. P. Angew. Chem., Int. Ed. 2007, 46,
192−2194.
16) Dias, H. V. R.; Gamage, C. S. P.; Keltner, J.; Diyabalanage, H. V.
(
7
(
2
(
K.; Omari, I.; Eyobo, Y.; Dias, N. R.; Roehr, N.; McKinney, L.; Poth,
T. Inorg. Chem. 2007, 46, 2979−2987.
(
17) Chavez-Gil, T.; Cedeno, D. L.; Hamaker, C. G.; Vega, M.;
Rodriguez, J. J. Mol. Struct. 2008, 888, 168−172.
18) Lorono-Gonzalez, D. J. Acta Crystallogr., Sect. C 2008, 64,
M228−M232.
19) Blagg, R. J.; Adams, C. J.; Charmant, J. P. H.; Connelly, N. G.;
(
(
Haddow, M. F.; Hamilton, A.; Knight, J.; Orpen, A. G.; Ridgway, B. M.
Dalton Trans. 2009, 8724−8736.
(
20) Prananto, Y. P.; Turner, D. R.; Duriska, M. B.; Lu, J. Z.; Batten,
S. R. Inorg. Chim. Acta 2009, 362, 4646−4650.
21) Saly, M. J.; Heeg, M. J.; Winter, C. H. Inorg. Chem. 2009, 48,
303−5312.
22) Marzano, C.; Pellei, M.; Alidori, S.; Brossa, A.; Lobbia, G. G.;
Tisato, F.; Santini, C. J. Inorg. Biochem. 2006, 100, 299−304.
23) Kou, X.; Wu, J.; Cundari, T. R.; Dias, H. V. R. Dalton Trans.
(
5
(
(
2
(
(
009, 915−917.
24) Janiak, C. J. Chem. Soc., Chem. Commun. 1994, 545−547.
25) Janiak, C.; Scharmann, T. G.; Brzezinka, K. W.; Reich, R. Chem.
Ber. 1995, 128, 323−328.
(
26) Janiak, C.; Scharmann, T. G.; Green, J. C.; Parkin, R. P. G.;
Kolm, M. J.; Riedel, E.; Mickler, W.; Elguero, J.; Claramunt, R. M.;
Sanz, D. Chem.Eur. J. 1996, 2, 992−1000.
(
27) Janiak, C.; Scharmann, T. G.; Gunther, W.; Girgsdies, F.;
Hemling, H.; Hinrichs, W.; Lentz, D. Chem.Eur. J. 1995, 1, 637−
644.
(
(
(
(
28) Lu, D. M.; Winter, C. H. Inorg. Chem. 2010, 49, 5795−5797.
29) Groshens, T. J. J. Coord. Chem. 2010, 63, 1882−1892.
30) Wang, Y. L.; Cao, R.; Bi, W. H. Polyhedron 2005, 24, 585−591.
31) Snyder, C. J.; Martin, P. D.; Heeg, M. J.; Winter, C. H. Chem.
Eur. J. 2013, 19, 3306−3310.
(
(
32) Hall, T. L.; Ruff, J. K. Inorg. Chem. 1981, 20, 4444−4446.
33) Kirtley, S. W.; Andrews, M. A.; Bau, R.; Grynkewich, G. W.;
Marks, T. J.; Tipton, D. L.; Whittlesey, B. R. J. Am. Chem. Soc. 1977,
9, 7154−7162.
34) Ehemann, M.; Noth, H.; Davies, N. Z. Anorg. Allg. Chem. 1972,
89, 235−246.
35) Chernyshev, V. M.; Zemlyakov, N. D.; Il’in, V. B.; Taranushich,
V. A. Russ. J. Appl. Chem. 2000, 73, 839−841.
36) Klapotke, T. M.; Sabate, C. M.; Stierstorfer, J. New J. Chem.
009, 33, 136−147.
37) Grakauskas, V.; Albert, A. H. J. Heterocycl. Chem. 1981, 18,
477−1479.
38) Shastin, A. V.; Godovikova, T. I.; Korsunsky, B. L. Khim.
Geterotsikl. Soedin. 1998, 416−417.
39) Shastin, A. V.; Godovikova, T. I.; Korsunsky, B. L. Chem.
Heterocycl. Compd. 1998, 34, 383.
9
(
3
(
(
2
(
1
(
(
(
(
40) Wiesboeck, R. A.; Ruff, J. K. J. Org. Chem. 1968, 33, 1257−1258.
41) MacLeod, I. T.; Tiekink, E. R. T.; Young, C. G. J. Organomet.
Chem. 1996, 506, 301−306.
5
558
dx.doi.org/10.1021/ic400504h | Inorg. Chem. 2013, 52, 5551−5558