Syntheses and structures of N-phenylmaleimidetriazoles and by-products

Article abstract of DOI:10.1007/s10870-005-1693-y

The syntheses, properties, and structures of N-phenylmaleimidetriazole derivatives are described. Intermediates and by-products are also discussed. 1b. a = 43.997(7) A, 5.7610(9) A, 8.245(1) A, β = 99.339(4)°, C₂/c; 2a. a = 13.646(4) A, b = 7.7

Full text of DOI:10.1007/s10870-005-1693-y

ꢀC
Journal of Chemical Crystallography, Vol. 35, No. 5, May 2005 ( 2005)
DOI: 10.1007/s10870-005-1693-y
Syntheses and structures of N-phenylmaleimidetriazoles
and by-products
Yingqun Mao,(1) Iain Maley,(1) and William H. Watson(1)∗
Received August 11, 2004; accepted December 1, 2004
The syntheses, properties, and structures of N-phenylmaleimidetriazole derivatives are
˚
described. Intermediates and by-products are also discussed. 1b. a = 43.997(7) A,
◦
˚
˚
˚
˚
5.7610(9) A, 8.245(1) A, β = 99.339(4) , C2/c; 2a. a = 13.646(4) A, b = 7.744(2) A, c =
◦
˚
◦
˚
˚
˚
˚
10.612(3) A, β = 91.979(6) , P21/c. 3a. a = 22.245(1) A, b = 22.245(1) A, 10.010(1) A,
ꢁ
◦
˚
˚
P42/n. 3a . a = 11.727(2) A, b = 14.075(3) A, c = 16.080(3) A, α = 105.859(3) , β =
◦
˚
˚
˚
105.331(3) , γ = 98.187(3) , P-1. 3b. a = 8.561(3) A, b = 14.755(5) A, c = 22.771(7) A,
◦
˚
˚
˚
β = 97.006(5) , P21/c. 3c. a = 10.500(2) A, b = 12.189(2) A, c = 13.040(2) A,
◦
◦
◦
˚
α = 109.091(3) , β = 106.089(3) , γ = 101.022(3) , P-1. 8a. a = 16.389(8) A,
◦
˚
˚
˚
b = 5.749(3) A, c = 19.316(3) A, β = 97.467(9) , P21/n. 8b. a = 5.822(2) A, b =
◦
◦
◦
˚
˚
˚
10.114(3) A, c = 16.705(4) A, α = 84.681(5) , β = 82.840(5) , γ = 75.769(4) , P-1. 9b.
◦
˚
˚
˚
˚
a = 11.251(1) A, 13.335(3) A, 13.376(3) A, β = 102.456(4) , P21/n. 9c. a = 15.836(3) A,
◦
˚
˚
b = 8.236(2) A, c = 5.447(3) A, β = 92.551(3) , P21/c. 10a. a = 13.177(2) A, b =
14.597(2) A, c = 5.5505(8) A, β = 110.979(2)◦, Cc. 11a. a = 14.720(2) A,
˚
˚
˚
˚
◦
◦
◦
˚
˚
b = 13.995(2) A, c = 38.245(6) A, β = 94.430(3) , P21/n. 12b. a = 15.067(5) A,
◦
◦
˚
˚
b = 20.378(6) A, c = 8.669(5) A, α = 99.16(4) , β = 99.32(3) , γ = 105.23(3) ,
˚
˚
˚
P-1. 13b. a = 8.2824(6) A, b = 10.5245(7) A, c = 15.518(1) A, α = 92.305(1) ,
◦
◦
˚
˚
β = 100.473(1) , γ = 100.124(1) , P-1. 15a. a = 15.357(3) A, b = 7.778(2) A,
˚
˚
˚
˚
c = 22.957(2) A, Pbca. 16b. a = 18.0384(4) A, b = 12.474(3) A, c = 20.078(5) A, Pbca.
KEY WORDS: N-phenylmaleimide; triazole; diazide; phosphoranes.
Introduction
A number of moieties have been added to the
2-aminofunctionality and some have displayed in-
teresting nonlinear optical properties.4 Although
reaction of the diazide of N-phenylmaleimide in
refluxing dichloromethane is reported to give the
triazole,5 initially we had difficulty with this reac-
tion and isolated primarily the normal Staudinger
product.6 A major problem in the formation, iso-
lation and recrystallization of the triazole is the
instability of the fused five-membered rings. In
the presence of methanol or ethanol the maleimide
ring in 3 opens to give the ester 11 (see Scheme 1).
The di-Staudinger side product 14 is readily
We have studied extensively reactions of the
vicinal diazides of 2,3- dichloroquinones to form
2-amino-1,2,3-triazole derivatives.1−3 At room
temperature or in refluxing ethanol the domi-
nant product is the triazole while at lower tem-
peratures the di-Staudinger product is formed.
(1) Department of Chemistry, Texas Christian University, Fort Worth,
Texas, USA.
∗ To whom correspondence should be addressed at Department of
Chemistry, Texas Christian University, Box 299870, Fort Worth,
Texas 76129, USA; e-mail: w.watson@tcu.edu.
385
ꢀ
C
1074-1542/05/0500-0385/0 2005 Springer Science+Business Media, Inc.

386
Mao, Maley, and Watson
Scheme 1.
isolated because of its stability. Under some con-
ditions products such as 15 and 16 were isolated,
but their formation is difficult to rationalize. Af-
ter numerous efforts the formation of the triph-
enylphosphine 3 is now routine with the R group
being H, F or NO2. With the quinone series of
compounds the triphenylphosphine was removed
by hydrolysis to form the amine which was then
reacted with a variety of aldehydes. Although
small quantities of the amine 10 have been iso-
lated, compound 3 primarily opens to form the
acid and other complex products. The direct re-
action between the aldehyde and 3 is used to
form the condensation products 4–9. In this pa-
per we discuss the synthesis of all compounds
and the crystal structures of compounds 1b, 2a,
3a, 3aꢁ, 3b, 3c, 8a, 8b, 9b, 9c, 10a, 11a, 13b,
15a, and 16a.

N-phenylmaleimidetriazoles and by-products
Experimental
387
poured into ice water. A pale white solid was re-
covered via filtration and was washed with water
and ether giving a yield of 30–38%. TLC showed
one spot (EtOAc:hexanes 1:2). Additional prod-
uct was obtained by extracting the filtrate with
CH2Cl2, washing the organic phase with brine,
drying over anhydrous sodium sulfate and remov-
ing the solvent by vacuum (total yield ∼76%).
Starting materials were used as purchased
without further purification. Solvents were dried
following standard procedures. IR spectra were
recorded on a Midac Systems FTIR using KBr
pellets. All NMR spectra were obtained with a
Vairan Mercury Plus 300 Spectrometer operat-
ing at 300.053 MHz for 1H and 75.457 MHz for
13C with TMS as internal standard and CDCl3 as
solvent unless otherwise specified. Mass spectra
were obtained using a Hewlett Packard 5989A
Spectrometer. All X-ray data except for com-
pound 12b were collected on a Bruker SMARTTM
1000 CCD-based diffractometer. Frame collec-
tion was designed to insure essentially 100%
coverage at 10 s per frame. The frames were in-
tegrated with the SAINT software package7 us-
ing a narrow-frame integration algorithm, and
the structures were solved and refined using the
SHELXTL program package.8 Data for com-
pound 12b were collected on a Rigaku AFC6S
diffractometer. All structures were analyzed with
PLATON.11 Compound 11 contains three inde-
pendent molecules per cell. The N-phenyl groups
are disordered. No symmetry operation could be
found relating the three molecules, and the struc-
ture could not be solved in any higher symmetry
space group. Table 1 contains crystal data, col-
lection parameters, and refinement criteria for all
compounds. Table 2 contains averaged values for
selected distances and angles in the fused five-
membered ring system. Thermal ellipsoids are
drawn at the 50% probability level.
N-4-fluorophenyldichloromaleimide (1b)
Pale white solid, mp 161–163◦C. MS(m/z):
259(M+, 100), 182(28), 180(86), 137(71),
122(26), 109(53), 96(20).1H NMR: δ 7.50(dd J
9.0, 5.1 Hz 2H), 7.31(dd J 9.0, 8.1 Hz 2H).
13C NMR: δ 164.08, 162.17, 160.78, 133.88,
128.26, 128.14, 126.66, 116.86, 116.55.
N-4-nitrophenyldichloromaleimide (1c)
Dark red solid, mp 188–190◦C. MS(m/z)
286(M+, 100), 258(42), 256(62), 230(21),
228(31), 184(36), 134(23), 106(22), 94(26).
1H NMR: δ 8.37(d J 7.2 Hz 2H), 7.68(d J 6.9 Hz
2H). 13C NMR: δ 161.49, 146.92, 136.42, 134.38,
125.90, 124.96.
General procedure for the synthesis of
N-arylmaleimidediazide (2)
A solution of N-aryldichloromaleimide and
2.4 eq. sodium azide in methanol was stirred
overnight. The solvent was removed under vac-
uum, the residue dissolved in dichloromethane,
washed with water and brine, dried over anhy-
drous sodium sulfate, and the solvent removed
by vacuum to give a yellow solid (>90%). TLC
showed one spot (Hexanes EtOAc = 1:1).
General procedure for synthesis of
N-aryldichloromaleimides (1)
To a solution of dichloromaleic anhydride in
diethyl ether at reflux was added dropwise a so-
lution of aniline, p-fluoroaniline, or p-nitroaniline
(1 eq) in diethyl ether. The reflux was contin-
ued for 1 to 2 h and the solvent then was re-
moved with a Rotavap. The residue was treated
with acetic anhydride and NaOAc and heated at
95◦C for 4 h. The resulting dark solution was
N-phenylmaleimidediazide (2a)
1H NMR: δ 7.47–7.26 (m). 13C NMR:
δ 163.82, 130.55, 129.52, 128.53, 125.85, 119.56,
119.92.

388
Mao, Maley, and Watson
Table 1. Crystal and Refinement Data for Compounds 1b, 2a, 3a, 3aꢁ, 3b, 3c, 8a, 8b, 9b, 9c, 10a, 11a, 12b, 13b, 15a, and 16b
Compound
1b
2a
3a
Formula
C10H4Cl2FNO2
246234
260.04
C10H5N7O2
245041
255.21
C28H20N5O2P
245044
489.46
CCDC Deposit No.
Formula weight
Crystal dim., mm
Temperature, K
Crystal system
Space group
0.54 × 0.26 × 0.12
0.40 × 0.21 × 0.097
0.39 × 0.16 × 0.090
297(2)
213(2)
297(2)
Monoclinic
C2/c
Monoclinic
P 21/c
Tetragonal
P 42/n
Unit cell dim.
˚
a(A)
43.997(7)
5.7610(9)
8.245(1)
90
99.339(4)
90
2062.2(6)
8
1.675
13.646(4)
7.744(2)
10.612(3)
90
91.979(6)
90
1120.8(6)
4
1.512
22.245(1)
22.245(1)
10.010(1)
90
90
90
4953.1(9)
8
1.313
˚
b(A)
˚
c(A)
α(◦)
β(◦)
γ (◦)
3
˚
Volume, A
Z
D
calcd, Mg/m3
µ (mm−1
)
0.624
0.114
0.147
Reflections measure
Indep. Refl./Rint
Absorp. Correction
Max./min. transmis.
Data/restr./paramet.
GOF on F2
6848
4429
27941
1800/0.044
Empirical
0.3148/0.2595
1800/0/146
1.090
1464/0.035
Empirical
0.2718/0.2171
1464/0/173
0.987
3236/0.062
Empirical
0.7832/0.7225
3236/0/326
1.053
R1, R1(all)
Extinction coeff.
ρmax, ρmin
0.0403, 0.0512
0.0009(3)
0.19/−0.24
0.0285, 0.0371
0
0.15/−0.12
0.0698, 0.0875
0
0.12/−0.17
3aꢁ
3b
3c
8a
C
28H20N5O2P
C28H19FN5O2P.C3H6O
245036
C28H19N6O4P.C3H6O
245038
FeC21H15N5O2
245035
425.23
245043
489.46
565.53
611.53
0.22 × 0.18 × 0.068
0.40 × 0.20 × 0.16
0.16 × 0.07 × 0.06
.14 × .051 × .012
213(2)
213(2)
213(2)
213(2)
Triclinic
P -1
Monoclinic
P 21/c
Triclinic
P -1
Monoclinic
P 21/n
11.727(2)
14.075(3)
16.080(3)
105.859(3)
105.331(3)
98.187(3)
2395.4(8)
4
8.561(3)
14.755(5)
22.771(7)
90
97.006(5)
90
10.500(2)
12.189(2)
13.040(2)
109.091(3)
106.089(3)
101.022(3)
1440.4(4)
2
16.389(8)
5.749(3)
19.316(3)
90
97.467(9)
90
2855(2)
4
1084(2)
4
1.357
1.316
1.366
1.565
0.152
0.144
0.147
0.865
10079
21268
11554
10671
6245/0.038
Empirical
0.5321/0.3645
6245/0/650
1.042
5593/0.073
Empirical
.7440/4578
5593/0/373
1.048
5431/0.107
Empirical
—
5431/0/390
1.023
3213/0.137
Empirical
—
3213/0/262
0.974
0.0406, 0.0816
0.0020(3)
0.26/−0.27
0.0817, 0.113
0
0.54/−0.42
0.0542, 0.203
0
0.22/−0.19
0.0657, 0.133
0
0.69/−0.31

N-phenylmaleimidetriazoles and by-products
389
Table 1. Continued
8b
9b
9c
10a
FeC21H14FN5O2
245037
C21H19FN6O2
245039
C21H19N7O4
245040
C10H7N5O2
245042
443.22
406.42
433.43
229.21
0.34 × 0.04 × 0.029
0.42 × 0.30 × 0.21
0.65 × 0.35 × 0.30
0.26 × 0.21 × 0.15
213(2)
213(2)
213(2)
294(2)
Triclinic
P -1
Monoclinic
P 21/n
Monoclinic
P 21/c
Monoclinic
Cc
5.822(2)
10.114(3)
16.705(4)
84.681(5)
82.840(5)
75.769(4)
944.0(4)
2
11.251(1)
13.335(3)
13.376(3)
90
102.456(4)
90
15.836(3)
8.236(2)
15.447(3)
90
92.551(3)
90
13.177(2)
14.597(2)
5.5505(8)
90
110.979(2)
90
1959.6(7)
4
2012.8(6)
4
996.8(2)
4
1.559
1.378
1.430
1.527
0.838
0.100
0.103
0.113
6913
15793
15477
2037
3512/0.126
Empirical
0.7235/0.3844
3512/0/264
1.028
4472/0.079
Empirical
0.529/0.235
4472/0/274
0.996
4563/0.851
Empirical
0.5474/0.3273
4563/0/292
0.985
1226/0.023
Empirical
0.3307/0.2895
1226/2/163
1.006
0.0851, 0.154
0
1.15/−0.55
0.0532, 0.0933
0
0.30/−0.21
0.0604, 0.1495
0
0.28/−0.23
0.0246, 0.258
0.019(2)
0.09/−0.09
11a
12b
13b
15a
16b
C
29H24N3O3P
C28H19O2N2ClPF
245749
500.95
C28H16O2N2Cl4OFP
245753
604.2
C16H11N2O2C
245751
298.72
C28H19PNO3F
245750
467.41
245752
521.52
.68 × .38 × .20
.50 × .40 × .30
.24 × .09 × .04
.75 × .28 × .03
.13 × .09 × .07
302(2)
298(2)
213(2)
213(2)
213(2)
Monoclinic
P21/n
Triclinic
P-1
Triclinic
P-1
Orthorhombic
Pbca
Orthorhombic
Pbca
14.720(2)
13.995(2)
38.245(6)
90
94.430(3)
90
15.067(5)
20.378(6)
8.669(5)
99.16(4)
99.32(3)
105.23(3)
2477(2)
4
8.2824(6)
10.5245(7)
15.518(1)
92.305(1)
100.473(1)
100.124(1)
1305.8(2)
2
15.357(3)
7.778(2)
22.957(2)
90
90
90
18.038(4)
12.474(3)
20.078(5)
90
90
90
7864(2)
12
2742(1)
8
4518(2)
8
1.321
1.343
1.537
1.447
1.374
0.146
0.255
0.533
0.284
0.162
44309
2588
7568
10462
17868
10252/0.067
Empirical
.4068/.2309
10252/0/1403
1.064
0.0521, 0.0848
0.000050(8)
0.31/−.025
2402/0.064
Empirical
.996/.756
2402/0/632
∗
3408/0.043
Empirical
.4203/.2655
3408/0/344
1.035
0.0393, 0.0420
0.
0.39/−0.20
1794/0.092
Empirical
.4386/.1795
1795/0/195
1.025
0.0370, 0.0499
0
0.19/−0.21
2947/0.124
Empirical
.3182/.1857
2947/0/308
0.988
.0510, 0.0958
0
0.22/−0.33
0.040, −045
0
0.17/−0.15
∗Old data GOF not available.

390
Mao, Maley, and Watson
Table 2. Distances and Angles Around the Fused Five-Membered
Rings. Average Distances and Angles in the Five Independent
Molecules in 3a, 3aꢁ, 3b, and 3c are Listed Under Column Heading A
complete. The solution was cooled and the solvent
left to partially evaporate in the air. The solution
was filtered and the precipitate was washed with
acetone until the red color was gone leaving a
yellow solid. The original filtrate was evaporated
to dryness and was again treated with acetone
yielding a second crop of yellow product (total
yield ∼50–60%).
Phosphorane 3a, [5-phenyl-2-(triphenyl-λ5-
phosphanylideneamine)-2H-(pyrrolo[4,5-
d][1,2,3]-triazole)-1,4-dione]
A
B
10
----
C(1) C(2)
1.475(4)
1.352(9)
1.475(3)
1.424(3)
1.425(10)
1.346(4)
1.346(6)
1.353(11)
1.346(8)
1.367(7)
1.610(4)a
1.200(3)
1.204(3)
1.478(6)
1.368(9)
1.472(11)
1.426(7)
1.428(6)
1.334(3)
1.348(8)
1.348(12)
1.339(9)
1.386(9)
1.296(13)b
1.201(8)
1.201(9)
117.2(1.3)
125.4(7)
113.6(2.2)
1.471(3)
1.366(3)
1.474(3)
1.399(3)
1.422(3)
1.334(3)
1.337(2)
1.338(2)
1.336(2)
1.394(3)
—
1.197(2)
1.207(2)
119.1(2)
122.7(2)
—
----
C(2) C(3)
----
C(3) C(4)
Yellow solid from acetone, mp 215–
----
C(4) N(1)
217◦C. MS(m/z): 489(M+,11), 342(36), 304(32),
----
N(1) C(1)
----
C(2) N(2)
1
263(20), 262(100), 183(23). H NMR: δ 7.87(m
----
N(2) N(3)
6H), 7.62(m 3H), 7.52(m, 6H), 7.45(m, 2H),
----
N(3) N(4)
7.32(m, 3H). 13C NMR: δ, 159.11(C O), 143.14
----
---
N(4) C(3)
---
----
N(3) N(5)
and 143.12 (2C in triazole ring), 133.40, 133.30,
133.05, 133.02, 131.76, 129.03, 128.96, 128.90,
127.89, 126.99, 126.31, 125.31. A single phos-
phorus resonance is observed. Recrystallization
from toluene gave polymorph 3a while recrystal-
lization from nitromethane gave polymorph 3aꢁ.
----
N(5)
X
----
C(1) O(1)
----
C(4) O(2)
----
----
----
N(2) N(3) N(5)
118.6(8)
124.2(8)
117.1(7)
----
N(4) N(3) N(5)
---- ----
N(3) N(5)
X
Note. Average distances and angles for molecules 8a, 9a, 9b and 9c
are listed under column heading B. Values for the free amine are
listed under 10.
Phosphorane 3b
aX = P; bX = C.
Yellow solid from acetone, mp 195–
197◦C. MS(m/z): 507(M+,2), 278(24), 277(59),
262(100), 183(68), 137(28), 109(20), 108(37).
1H NMR: δ 7.87(m 6H), 7.62(m 3H), 7.52(m,
6H), 7.27(m, 2H), 7.12(t J 4.8 Hz 2H) . 13C NMR:
δ 163.67, 160.39, 159.28, 143.29, 143.27, 133.66,
133.52, 133.32, 133.28, 129.30, 129.13, 129.10,
128.98, 127.98, 127.94, 126.73, 125.39, 116.33,
116.03.
N-4-fluorophenylmaleimidediazide (2b)
1H NMR: δ 7.52–6.97(m). 13C NMR(partial):
122.63, 122.52, 116.69, 116.38, 116.82, 115.82.
N-4-nitrophenylmaleimidediazide (2c)
1H NMR: δ 8.29(d J 9.3 Hz 2H), 7.74(d J
9.3 Hz 2H).
Phosphorane 3c
General procedure for synthesis
Yellow solid from acetone, mp 230–232◦C.
MS(m/z): 534(M+,2), 278(43), 277(90), 262(41),
183(41), 77(100). 1H NMR: δ 8.30(d J 8.7 Hz 2H),
7.88(m 6H), 7.58(m, 11H). 13C NMR: δ 158.31,
146.21, 143.07, 138.07, 133.65, 133.51, 133.43,
133.40, 129.36, 129.19, 126.74, 126.42, 125.09,
124.49.
of phosphorane derivatives (3)
To a solution of N-arylmaleimidediazide
in refluxing dichloromethane, 1.2 equivalents
of triphenyl-phosphine in dichloromethane was
added drop wise via an addition funnel. The re-
flux was continued for an hour after addition was

N-phenylmaleimidetriazoles and by-products
391
General procedure for synthesis
of the Schiff bases
Compound 6a
Red needles from CHCl3, mp 228–229◦C.
MS(m/z): 388(M+,100), 389(28), 373(64),
175(24), 161(29), 104(21), 91(22), 89(24).
1H NMR: δ 9.22(s, 1H), 7.82(d, J 9.0 Hz 2H),
7.52(dd, J 6.0, 6.0 Hz, 2H), 7.41(m, 3H), 6.72(d,
J 9.3 Hz, 2H), 3.47(q, J 6.9 Hz, 4H), 1.24(t, J 7.0
Hz, 6H). 13C NMR: δ 158.28, 158.22, 151.85,
145.80, 132.51, 131.31, 129.15, 128.48, 126.90,
117.22, 111.26, 44.70, 12.50. Elemental analysis:
Calcd: C 64.94%, H 5.19%, N 21.64%, Found: C
64.96%, H 5.38%, N 21.38%.
The phosphorane and 1.5 eq. of the appro-
priate aldehyde in a solution of dichloromethane
and acetic acid (3:1 by volume) were heated at
60◦ until TLC detected no phosphorane remain-
ing. The precipitate was filtered and washed with
chloroform to give a solid in a yield of ∼80%.
Compound 4a
White needles from CH2H2, mp 224–226◦C.
MS(m/z): 317(M+, 98), 90(100), 77(23). 1H
NMR (DMF-d7): δ 9.66(s, 1H), 8.19(d, J 8.1
Hz 2H), 7.71–7.45(m, 8H); 13C NMR (DMF-d7):
δ 160.06, 159.25, 148.03, 134.29, 132.79, 132.25,
130.55, 130.07, 129.70, 129.31, 128.49.
Compound 6b
Red needles from acetone, mp 223–224◦C.
MS(m/z): 406(M+,100), 407(30), 391(77),
392(20), 175(26), 161(31), 146(20), 133(22),
104(23), 89(32). 1H NMR: δ 9.21(s, 1H), 7.82(d,
J 8.7 Hz, 2H), 7.38(dd, J 8.7, 5.1 Hz 2H), 7.19(dd,
J 8.6, 8.6 Hz 2H), 6.72(d, J 9.0 Hz, 2H), 3.47(q,
J 7.1 Hz, 4H), 1.24(t, J 7.2 Hz, 6H). 13C NMR: δ
163.75, 160.46, 158.36, 158.16, 151.88, 145.67,
132.54, 128.84, 128.73, 127.22, 127.18, 117.16,
116.33, 116.03, 111.26, 44.70, 12.49. Elemental
analysis: Calcd: C 62.06%, H 4.71%, N 20.68%,
Found: C 62.26%, H 4.97%, N 20.70%.
Compound 4b
White solid from acetic acid, mp 237–239◦C.
MS(m/z): 335(M+, 39), 90(100), 89(27). 1H
NMR(DMF-d7): δ 9.66(s 1H), 8.19(d, J 6.6 Hz,
2H), 7.76–7.59 (m, 5H), 7.44(t, J 8.4 Hz, 2H).
13C NMR (DMF-d7): δ 161.00, 158.23, 157.30,
146.07, 132.40, 130.33, 128.91, 128.80, 128.67,
128.16, 114.89, 114.58 (due to the low concentra-
tion or overlap the numberoflines were fewer than
expected); Elemental analysis: Calcd. C 60.90%,
H 3.01%, N 20.89%, Found: C 60.94%, H 3.12%,
N, 21.06%.
Compound 6c
Red needles from CH2Cl2/HOAc, mp 245–
246◦C MS(m/z): 433(M+,14), 418(25), 174(29),
161(20), 159(83), 146(26), 144(34), 134(20),
133(33), 132(26), 131(100), 130(24), 129(56),
118(29), 116(22), 115(23), 111(22), 109(24),
104(30), 102(58), 93(23), 90(53), 89(26);
1H NMR(DMF-d6): δ 9.37(s, 1H), 8.51(d, J 9.0 Hz
2H), 7.90(m, 4H), 6.92(d, J 9.1 Hz, 2H),
3.56(q, J 7.0 Hz, 4H), 1.22(t, J 7.0 Hz, 6H).
13C NMR(DMF-d6): δ 162.90, 159.67, 158.83,
152.74, 147.12, 138.60, 133.09, 128.87, 124.97,
117.97, 112.18, 44.99, 12.71. Elemental analysis:
Calcd: C 58.19%, H 4.42%, N 22.62%, Found: C
58.37%, H 4.54%, N 22.48%.
Compound 5a
Pale yellow solid from acetic acid does
not melt, but turns dark at 268◦C and sub-
limes. MS(m/z): 362(M+,77), 135(39), 119(50),
1
91(30), 89(100). H NMR(DMF-d7): δ 9.84(s,
1H), 8.50(m, 4H), 7.58(m, 5H). 13C NMR(DMF-
d7): δ 162.95, 159.13, 157.92, 150.99, 148.45,
133.28, 131.61, 129.374, 129.40, 128.47, 125.03.
Elemental analysis: Calcd. C 56.36%, H 2.78%,
N 23.20%, Found C 56.50%, H 2.77%, N 23.36%.

392
Mao, Maley, and Watson
Compound 7a
147.16, 130.64, 130.52, 128.84, 119.33, 116.56,
116.25, 75.11, 74.00, 70.66, 70.45. Elemental
analysis: Calcd. C 56.91%, H 3.18%, N 15.80%,
Found: C 56.76%, H 3.27%, N 15.68%.
Yellow-green solid from acetic acid which
sublimes >216◦C. MS (m/z): 320(M+,9), 229(39),
1
119(100), 93(20). H NMR (DMF-d7): δ 9.39(s,
1H), 7.62–7.48(m, 5H), 7.44(br, 1H), 7.23(dd,
J 4.2, 1.8 Hz, 1H), 6.38(dd, J 4.2, 2.4 Hz 1H),
4.11(s, 3H). 13C NMR (DMF-d7): δ 159.42,
150.13, 147.30, 134.47, 132.87, 129.66, 129.17,
128.49, 125.94, 123.94, 111.13, 37.17. Elemental
analysis: Calcd. C 60.00%, H 3.78%, N 26.24%,
Found C 59.69%, H 3.91%, N 26.32%.
Compound 9c
Dark red solid from acetic acid does not melt
below 340◦C. MS(m/z): 470(M+,71), 212(22),
211(89), 198(31), 196(26), 121(100), 90(20).
1H NMR: δ 9.54(s, 1H), 8.51(d, J 9.2 Hz 2H),
7.90(d, J 9.1 Hz, 2H), 5.07(t, J 1.8 Hz, 2H), 4.86(t,
J 1.8 Hz, 2H), 4.41(s, 5H). 13C NMR: δ163.70,
158.80, 147.59, 147.34, 138.54, 128.94, 125.01,
75.26, 74.31, 70.94, 70.69. Elemental analysis:
Calcd: C 53.64%, H 3.00%. Found: C 53.36%,
H 3.09%.
Compound 8a
Yellow-brown solid from acetic acid
mp >360◦C. MS(m/z): 352(M+,54), 119(53),
1
91(41), 79(100). H NMR (DMF-d7): δ 9.62(s,
1H), 7.94(d, J 3.6 Hz, 1H), 7.87(d J 3.9 Hz 1H),
7.65–7.50(m, 5H). Elemental analysis: Calcd. C
51.14%, H 2.29%, N 23.86%, Found C 50.93%,
H 2.07%, N 23.60%.
Compound 10a
In general, the free amine cannot be recov-
ered easily due to opening of the five-membered
ring. A suspension was prepared by adding 3a to
25 mL of 1:1 water and 6N HCl and stirred for two
days. A small amount of white solid was recov-
ered and recrystallized from nitromethane, m.p.
224–226. The crystal structure 10a confirmed the
structure as that of the free amine.
Compound 9a
Dark red needles from CH2Cl23/CH3NO2
turn white around 200◦C and melt >300◦C.
MS(m/z): 425(M+,100), 198(33).121(22). 1H
NMR δ: 9.38(s, 1H), 7.45–7.35(m, 5H), 4.93(s,
2H), 4.74(s, 2H), 4.32(s, 5H). 13C NMR: δ 162.32,
158.80, 146.47, 133.76, 132.42, 128.98, 128.83,
74.14, 73.53, 70.52, 70.00. Elemental analysis:
Calcd. C 59.32%, H 3.56%, Found C 59.48%,
H 3.70%.
Compound 11
Compound 11 is isolated when 3 is prepared
in refluxing ethanol or methanol. Beautiful crys-
tals of 11 can be grown by placing the insoluble
3 in methanol or ethanol and letting it stand in
a closed vial. Compound 3 is quantitatively con-
verted into 11.
Compound 9b
Dark red solid from acetic acid turns
black then colorless but does not melt below
340◦C. MS(m/z): 443(M+,70), 212(25), 211(55),
198(74), 196(51), 185(36), 171(21), 142(32),
137(42), 109(45), 82(20). 1H NMR: δ9.38(s, 1H),
7.38(dd J 13.8, 4.8 Hz 2H), 7.23(dd J 15.0,
7.7 Hz, 2H), 4.93(s, 2H), 4.75(s, 2H), 4.32(s, 5H).
13C NMR(DMF-d7): δ164.24, 160.98, 159.19,
Compounds 12b and 13b
Compounds 12b and 13b were obtained
when 1b was not reacted quantitatively and
the resulting monoazide is reacted with triph-
enylphosphine or tri(p-chlorophenyl)phosphine.

N-phenylmaleimidetriazoles and by-products
393
Fig. 1. Packing diagram for compound 1b.
Compound 13b: m.p. 206–208◦C. MS(m/z):
606(49), 604(96), 602(73), 430(100). Elemental
analysis: Calcd: C,55.61%, H, 2.65%, N, 4.63%.
Found: C, 56.02%, H, 3.01%, N,4.63%.
Discussion
Figure 1 is a packing diagram for com-
pound 1b. The five- and six-membered rings are
planar forming an interplanar angle of 64.5(2)◦.
There are two short intermolecular contacts
[O(1)· · ·C(4) = 2.996(3) and C(1)· · ·O(2) =
Compound 14
˚
2.945(3) A] and one hydrogen bond like inter-
This is the red by-product always present
during the preparation of 3. m.p 255–257◦C, 256–
258◦C (Lit5). 1H NMR: Complex multiplet 7.15–
7.30. Elemental Analysis: Calcd: C,76.34%, H,
4.87%, N, 5.81%. Found: C, 76.12%, H, 4.32%,
N, 5.90%.
˚
---
action [C(7) H(2) = 0.93 A, H(2)· · ·F(1) =
˚
˚
---
2.53 A, C(7)· · ·F(1) = 3.340(5) A, and C(7)
H(2)· · ·F(1) = 146◦].
Figure 2 is a thermal ellipsoid drawing for
compound 2a. The two azide groups are oriented
away from each other, and the azide groups are
◦
---
---
not linear [(N(2) N(3) N(4) = 169.2(2) and
◦
---
---
N(5) N(6) N(7) = 169.3(2) ]. The five- and
six-membered rings are planar and form an in-
terplanar angle of 44.2(2)◦ which is about 20◦
smaller than in compound 1b. The two azide
groups are twisted in the same direction out of
the plane of the five-membered ring by 11.5(3)
Compound 15
This by-product might be rationalized as the
attack of aniline on compound 1; however, this
product was obtained only once and the exact re-
action conditions are not known. m.p. 188–190◦C.
1H NMR: 7.40(m), 7.24(m). MS(m/z): 297(M+,
70), 296(39), 233(26), 177(21), 176(27).
◦
--- --- ---
and by 12.7(3) . The C N N N distances for
the two groups average 1.394(2), 1.254(2), and
˚
1.254(3) A. The shortest intermolecular interac-
tions involve the terminal nitrogen atoms on
˚
the azide groups [N(4)· · ·H(6) = 2.63 A and
Compound 16
˚
N(7)· · ·C(4) = 2.982(2) A].
Compound 16 was obtained once, and we
have no logical explanation of how it might be
formed. M.p. 245–247◦C. Elemental Analysis:
Calcd: C, 71.95%, H, 4.10%, N, 3.00%. Found:
C, 72.17%, H, 4.21%, N, 3.04%.
Figure 3 is a packing diagram for polymorph
3a. This crystal is yellow-orange which may be
due to packing or a trace of the di-Staudinger side
product. All five- and six-membered rigs are pla-
nar and the two five-membered rings are fused

394
Mao, Maley, and Watson
Fig. 2. Thermal ellipsoid drawing of compound 2a with ellipsoids drawn at the
50% probability level.
−3
to form a planar eight-membered ring system.
The interplanar angle beween the five-membered
amide ring and the N-phenyl group is 55.6(1)◦
while the angle between the triazole ring and the
three phenyl rings C(11), C(17) and C(23) are
76.1(1)◦, 80.7(1)◦, and 9.0(1)◦ Distances and an-
gles involving the five-membered rings are pre-
sented in Table 2. The density of polymorphy 3a
˚
only 0.32 e A indicating no significant solvent
population.
Figure 4 is a packing diagram of poly-
morph 3aꢁ. The crystals are a brilliant yellow.
There are two independent molecules per cell,
and the space group and symmetry were inves-
tigated thoroughly.11 All five- and six-membered
rings are planar. The interplanar angles between
the two fused five-membered rings are 5.1(2) and
2.6(2)◦ while the N-phenyl maleimide interplanar
angles are 47.2(4) and 48.5(2)◦. The triazole ring
is 1.313 Mg/m3 while that of 3aꢁ is 1.357 Mg/m3.
3
Structure 3a contains a void space11 of 146 A ;
˚
however, the final difference map shows a ρmax of

N-phenylmaleimidetriazoles and by-products
395
interplanar angles with the three phenyl rings
of the triphenylphosphine moiety are 89.0(2),
16.4(2), 80.3(1) and 80.0(2), 26.7(2), 88.2(2)◦ for
the two independent molecules. The large dif-
ferences in interplanar angles indicate the two
molecules are really independent moieties in
the structure. The potential solvent void is to
3
˚
58 A which is about a third of that found in
polymorph 3a.
Figure 5 is a packing diagram of compound
3b, Unlike 3a and 3aꢁ, the molecules are well-
packed and there is no solvent void. The two
five-membered rings are planar and form a planar
eight-membered system. The angle between the
five-membered maleimide ring and the N-phenyl
group is 49.3(2)◦ while the triazole ring and the
three phenyls attached to phosphorus exhibit an-
gles of 13.3(2), 82.4(2) and 76.4(2)◦. There are
---
several short C H· · ·O interactions and one non-
classical hydrogen bond involving the fluorine
Fig. 3. Packing diagram of polymorph 3a.
˚
˚
---
atom: C(24) H = 0.94 A, H· · ·F(1) = 2.47 A,
◦
˚
---
C(24)· · ·F(1) = 3.302(5) A and C H· · ·F = 148 .
Fig. 4. Packing diagram of polymorph 3aꢁ.

396
Mao, Maley, and Watson
Fig. 5. Packing diagram of compound 3b.
Fig. 6. Packing diagram of compound 3c.

N-phenylmaleimidetriazoles and by-products
397
Fig. 7. Thermal ellipsoid drawing of compound 8a with ellipsoids drawn
at the 50% probability level.
Figure 6 is a packing diagram of compound
3c. The molecule crystallizes in space group P-1
and there is no solvent void in the structure. The
two five-membered rings are planar and form a
planar eight-membered ring. The angle between
the five-membered maleimide ring and the N-
phenyl group is 43.2(2)◦ while the triazole ring
exhibits angles of 34.2(2), 75.9(2) and 56.5(2)◦
with the three rings of the triphenylphosphine
moiety. There are no significant intermolecular
interactions.
The interplanar angle between the maleimide
ring and the N-phenyl group ranges from 42.3(2)
to 55.6(2)◦ in the five structures 3a, 3aꢁ (two
molecules), 3b, and 3c. The smallest inter-
planar angle between the triazole ring and a
phenyl ring attached to the phosphorus atom
varies from 9.0(1) to 34.2(2)◦. Packing interac-
tions strongly affect the orientation of the phenyl
rings.
Figure 7 is a thermal ellipsoid drawing of
compound 8a. All five- and six-membered rings
are planar. The maleimide ring and the N-phenyl
group exhibit an interplanar angle of 59.0(3)◦
The five-membered ferrocene ring attached to
C(1) is almost coplanar with the triazole ring
with an interplanar angle of 10.8(2)◦. The planar
Fig. 8. Packing diagram for compound 8.
---
---
---
N(3) N(5) C(11) C(12) moiety (torsion
angle −189.7(3)◦) is twisted slightly out of the

398
Mao, Maley, and Watson
---
---
---
---
---
triazole ring plane [N(2) N(3) N(5) C(11) =
are planar and the molecular moiety from C(5) to
N(6) is planar. The two methyl groups lie out the
plane in the same direction. The interplanar an-
gle between the maleimide ring and the N-phenyl
ring is 60.3(1)◦. There are no short intermolecular
interactions involving the fluorine atom, but there
are three hydrogen bond like polar interactions:
◦
---
−163.0(3) and N(5) C(11) C(12) C(13) =
10.6(6)◦]. The two five-membered rings of the
ferrocene are parallel with an interplanar angle
of 1.5(2)◦. The centroids of the two rings are
˚
1.643(2) andꢁ1.654(2) A from the Fe atom with a
◦
--- ---
Cg Fe Cg angle of 179.3(1) . The molecules
are well packed and there is no solvent accessible
volume.
˚
˚
˚
---
C(9) H(9)· · ·N(5) 0.94 A, 2.55 A, 3.464(3) A,
◦
˚
˚
---
and 164 ; C(14) H(14)· · ·O(2) 0.94 A, 2.49 A,
◦
˚
˚
---
Figure 8 is a packing diagram for com-
pound 8b. The crystals of this compound are
extremely small yielding a poor data set, and
the p-fluorophenyl group is disordered about the
N(1) C(5) C(8) axis. The maleimide and tria-
zole rings are planar as are the two five-membered
rings of the ferrocene moiety. The triazole ring
and the five-membered ferrocene ring attached
to C(1) are almost coplanar with an interplanar
3.419(2) A, 172 ; C(17) H(17)· · ·O(1) 0.94 A,
◦
˚
˚
2.51 A, 3.399(2) A, and 157 . There is no residual
solvent void in the structure.
Figure 10 is a packing diagram for com-
pound 9c. All five- and six-membered rings are
planar; however, unlike 9b the molecule from
C(5) to N(7) is not planar but has a twist at
---
---
---
N(5) C(11). The interplanar angle between the
maleimide ring and the N-phenyl group is 40.8(1)◦
while the angle between the triazole ring and
the phenylamine group is now 27.9(1)◦. The two
methyl groups are again twisted out of the plane
by 78.4(3) and −86.0(3)◦ and lie on the same
side of the phenylamine plane. There are two
nontraditional hydrogen bond like intermolecular
◦
---
---
---
---
angle of 6.7(5) . The N(2) N(3) N(5) C(11),
---
---
---
---
N(3) N(5) C(11) C(12) and N(5) C(11) ◦
---
C(12) C(13) torsion angles are −166.3(7) ,
−178.8(7)◦ and −16(1)◦ The distances of the Fe
atoms from the centroids of the five-membered
˚
rings are 1.636(4) and 1.663(4) A, and the
Cg Fe Cg angle is 179.1(3) . There is no resid-
ual solvent void in the structure.
Figure 9 is a thermal ellipsoid drawing of
compound 9b. All five- and six-membered rings
ꢁ
◦
˚
˚
˚
--- ---
---
interactions: C(6) H(6)· · ·O(3) 0.94 A, 2.52 A,
◦
˚
---
3.435(3) A, 165 ; C(11) H(11)· · ·O(2) 0.94 A,
◦
˚
˚
2.46 A, 3.334(3) A and 154 . There is no solvent
accessible void.
Fig. 9. Thermal ellipsoid drawing of compound 9b with ellipsoids drawn at the 50% probability level.

N-phenylmaleimidetriazoles and by-products
399
Fig. 10. Packing diagram for compound 9c.
Figure 11 is a thermal ellipsoid drawing
of compound 10a. The five- and six-membered
rings are planar with the maleimide ring mak-
ing angles of 2.8(1)◦ with the triazole ring and
Figure 12 is a thermal ellipsoid drawing
of compound 11a. All five- and six-membered
ring are planar and bond distances and angles
are internally consistent. Intramoleuclar hydrogen
bonds are formed between the amide hydrogen
and the oxygen atom of the ester carbonyl. The
molecules pack efficiently and there is no signif-
icant void space for solvent molecules. Although
there are no significant intermolecular interac-
tions, the crystals are very brittle and shatter upon
cleavage.
There is no drawing of compound 12b,
but the numbering is the same as that of com-
pound 13b in Fig. 12. There are two independent
molecules per cell. The five- and six-membered
rings are planar with the five-membered ring mak-
ing interplanar angles of 44.7(6) with the N-
Phenyl ring and, 10.2(5), 74.6(6) and 71.8(5)◦
with the three triphenylphosphine rings in
molecule 1 and 32.3(5), 88.3(5), 72.9(5) and
◦
˚
67.2(1) with the phenyl ring. N(5) lies 0.115 A
---
out of the triazole ring plane and the N(3) N(5)
bond makes an angle of 4.9(1)◦ to this plane.
The two amine hydrogen atoms form hydro-
gen bonds to oxygen and nitrogen atoms on
˚
---
adjacent molecules: [N(5) H(1) = 0.87(3) A,
˚
H(1)· · ·O(2) = 2.18(3) A, N(5)· · ·O(2) =
◦
˚
3.309(3) A with an angle of 168(2) ], the
˚
---
numbers for N(5) H(2)· · ·N(2) are [0.92 A,
◦
˚
˚
2.50(3) A, 3.149(3) A and 128(4) ], and for
˚
˚
---
N(5) H(2)· · ·N(4) are [0.92(3) A, 2.61(3) A,
◦
˚
3.527(3) A, and 177(2) ]. A polar interaction also
---
occurs for C(9) H(9)· · ·O(2) with distances and
◦
˚
˚
˚
angles being 0.93 A, 2.55 A, 3.412(3) A and 155 .
The structure is well-packed with no significant
void spaces.

400
Mao, Maley, and Watson
Fig. 11. Thermal ellipsoid drawing of compound 10a with ellipsoids drawn at
the 50% probability level.
12.7(5) in molecule 2. The structure exhibits
three non-classical intermolecular hydrogen
˚
H(36)· · ·F(1)
= 2.35 A, C(54)· · ·F(1) =
˚
3.13(1) A].
◦
---
bond interactions: [C(1) H(5)· · ·O(3) = 151 ,
Figure 13 is a thermal ellipsoid drawing
of compound 13b. The five- and six-membered
rings of 13b are planar with the five-membered
rings making interplanar angles of 46.3(1)◦
with the N-phenyl ring and 1.3(1), 78.6(1) and
˚
˚
H(5)· · ·O(3) = 2.44 A, C(12)· · ·O(3) = 3.33(1) A
--- ---
(where is C(12) H(5)); C(50) H(31)· · ·O(1) =
◦
˚
134 , H(31)· · ·O(1) = 2.32 A, C(50)· · ·O(1) =
134◦,
˚
---
3.09(1) A; C(54) H(36)· · ·F(1)
=
Fig. 12. Thermal ellipsoid drawing of the three independent molecules of compound 11a with
ellipsoids drawn at the 35% probability level.

N-phenylmaleimidetriazoles and by-products
401
Fig. 13. Thermal ellipsoid drawing of compound 13b.
67.4(1)◦ with the three triphenylphosphine rings.
The structure exhibits two non-classical hydro-
˚
H(28)· · ·O(2) = 2.44 A, C(28)· · ·O(2) =
˚
2.920(3) A].
Figure 14 is a thermal ellipsoid drawing of
compound 15a. The five- and six-membered rings
---
gen bond interactions: [C(21) H(21)· · ·F(1) =
◦
˚
141 , H(21)· · ·F(1) = 2.50 A, C(21)· · ·F(1) =
◦
˚
---
3.270(3) A; C(28) H(28)· · ·O(2) = 112 ,
are planar and the five-membered ring exhibits
Fig. 14. Thermal ellipsoid drawing of compound 15a with ellipsoids drawn at the 50% probability
level.

402
Mao, Maley, and Watson
interplanar angles of 37.1(1) and 54.2(1) with
Figure 15 is a thermal ellipsoid drawing of
compound 16. All ring systems in 16 are pla-
nar with the angle between the maleimide ring
and the N-phenyl group being 53.7(2)◦. The an-
gles between the maleimide ring and the three
triphenylphosphine phenyl groups are 53.7(2)◦,
59.1(2)◦ and 68.9(2)◦. There is no solvent void in
the structure.
---
---
the two six-membered rings. The O(1) C(1)
--- --- --- ---
C(2) N(1), N(1) C(2) C(3) Cl(1) and Cl(1)
---
---
---
C93) C94) O(2)
torsion
angles
are
−1.7(4), −4.1(4) and 2.2(4)◦. H(1) forms
intra- and intermolecular H ◦bonds to O(1):
---
---
[N(1) H(1)· · ·O(1) = 103(1) , N(1) H(1) =
˚
˚
0.85 A, H(1)· · ·O(1)
=
21.5(2) A, and
˚
---
N(1)· · ·O(1)= 2.827(3)A;N(1) H(1)· · ·O(1)(1-
Table 2 contains averaged distances for the
fused five-membered ring systems. Group A con-
tains a triphenylphosphine moiety attached to
◦
˚
x,1-y,1-z) = 155(2) , H(1)· · ·O(1) = 2.18(2) A
˚
and N(1)· · ·O(1) = 2.971(2) A.
Fig. 15. Thermal ellipsoid drawing of compound 16b with ellipsoids drawn at the 50%
probability level.

N-phenylmaleimidetriazoles and by-products
403
Acknowledgment
N(5). The distances are almost symmetric about
---
a line through N(1)· · ·N(3) although N(3) N(4)
We would like to thank the Robert A. Welch
---
may be slightly longer than N(2) N(3) due to
Foundation (Grant P-0074) for financial support.
---
---
the orientation of N(5). The N(4) N(3) N(5)
angle of 124.2(8)◦ is significantly larger than the
◦
References
---
---
N(2) N(3) N(5) angle of 118.6(2) . In series
B the attachment at N(5) is an extended delocal-
1. Sun, D.; Watson, W.H. J. Org. Chem. 1997, 62, 4082.
2. Sun, D.; Krawiec, M.; Campana, C.F.; Watson, W.H. J. Chem.
Crystallogr. 1997, 27, 5777.
3. Mendez-Rojas, M.A.; Bodige, S.G.; Ejsmont, K.; Watson, W.H.
J. Chem. Crystallogr. 2001, 31, 217.
4. a) Rangel-Rojo, R; Stranges, L.; Kar, A.K.; Mendez-Rojas,
M.A.; Watson, W.H. SPIE Proceedings 2001, 4 & 19, 514.
b) Rangel-Rojo, R.; Stranges, L.; Kar, A.K.; Mendez-Rojas,
M.A.; Watson, W.H. Optics Commun. 2002, 203, 385.
5. Mosby, W.L.; Silva, M.L. J. Chem. Soc. 1965, 1003.
6. Bodige, S.G.; Mendez-Rojas, M.A.; Watson, W.H. J. Chem.
Crystallogr. 1999, 29, 57.
---
---
---
ized moiety. Again the N(4) N(3) N(5) angle
◦
---
of 125.4(9) is larger than the N(2) N(3) N(5)
angle by 8.2 . The C(2) C(3) double bond in
series B has lengthened to 1.368(9) A com-
pared to the same bond of 1.352(7) A in series
◦
---
˚
˚
A. This might indicate withdrawal of electron
density due to the extended conjugation; how-
ever, the distance for the free amine (10 in
˚
7. Saint version 6.02; Bruker Analytical X-ray Systems, Inc.,
the table) is 1.366(3) A where no extended
Copyright 1997–1999.
8. SHELXTL Version 5.; Bruker Analytical X-ray Systems, Inc.,
Copyright 1998.
9. Sheldrick, G.M. SHELXS86. Program for the Solution of Crys-
tal Structures; University of Go¨ttigen, Germany, 1986.
10. TEXSAN for Windows: Crystal Structure Analysis Package,
Molecular Structure Corporation, 1997.
11. a) Spek, A.L. Acta Crystallogr. Sect. A 1990, 46, C34. b) Spek,
A.L. PLATON A Multipurpose Crystallographic Tool: Utrecht
University, Utrecht, The Netherlands, 2001.
---
---
conjugation occurs. The N(2) N(3) N(5) and
◦
---
---
N(4) N(3) N(5) angle difference is 3.6(2) in
compound 10.
Higher order nonlinear optical studies have
been initiated, and theoretical calculation stud-
ies will be presented along with these new
data.