N²-(2,6-Dibromo-4-nitro­phen­yl)-N¹,N¹-diethyl-2-(triisopropyl­silyl)ethanamidine

Molecules of the title compound, C₂₁H₃₅Br₂N₃O₂Si, form dimers by virtue of O(nitro)...H(isoprop­yl) inter­actions [O...H = 2.55 Å, O...C = 3.545 (3) Å and O...H—C = 171°].

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C)= 0.003 Å
• R factor = 0.022
• wR factor = 0.022
• Data-to-parameter ratio = 15.7

checkCIF/PLATON results

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Computing details

Data collection: COLLECT (Nonius, 1997–2001); cell refinement: DENZO/SCALEPACK; data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: CRYSTALS.

N²-(2,6-Dibromo-4-nitrophenyl)-N¹,N¹-diethyl-2- (triisopropylsilyl)ethanamidine

Crystal data

C21H35Br2N3O2Si	Z = 2
Mr = 549.42	F(000) = 564
Triclinic, P1	Dx = 1.470 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.5058 (2) Å	Cell parameters from 5676 reflections
b = 10.5180 (2) Å	θ = 1–27°
c = 12.7195 (2) Å	µ = 3.34 mm^−1
α = 84.5138 (9)°	T = 173 K
β = 88.4554 (8)°	Block, orange
γ = 78.6724 (8)°	0.20 × 0.16 × 0.10 mm
V = 1241.19 (4) Å^3

Data collection

Nonius Kappa CCD diffractometer	4137 reflections with I > 3σ(I)
Graphite monochromator	Rint = 0.013
φ and ω scans	θmax = 27.5°, θmin = 1.6°
Absorption correction: multi-scan DENZO/SCALEPACK (Otwinowski & Minor, 1997)	h = −12→12
Tmin = 0.55, Tmax = 0.72	k = −13→13
11254 measured reflections	l = −16→16
5691 independent reflections

Refinement

Refinement on F	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.022	Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) [weight] = 1.0/[A0*T0(x) + A1*T1(x) ··· + An-1]*Tn-1(x)] where Ai are the Chebychev coefficients listed below and x = F /Fmax Method = Robust Weighting (Prince, 1982) W = [weight] * [1-(deltaF/6*sigmaF)^2]^2 Ai are: 0.109 -0.105 -0.515E-01 -0.758E-01
wR(F^2) = 0.022	(Δ/σ)max = 0.001
S = 1.02	Δρmax = 0.35 e Å^−3
4137 reflections	Δρmin = −0.36 e Å^−3
263 parameters	Extinction correction: Larson (1970) equation 22
0 restraints	Extinction coefficient: 59.1 (20)
Primary atom site location: structure-invariant direct methods

Special details

Experimental. ¹H NMR (400 MHz, CDCl₃): δ 8.41 (s, 2H, H_Ar), 1.18 (s, 21H, ⁱPr); ¹³C NMR (125 MHz, CDCl₃): δ 133.5, 126.8, 126.1, 125.6, 109.7, 102.3, 18.6, 11.2; FAB MS: m/z 461 [M]⁺, 418 [M - ⁱPr]⁺; IR (solid, ν, cm^-1): 3099 (m), 3084 (m), 2941 (s), 2862 (s), 2160 (s), 1514 (versus), 1360 (versus), 1335 (versus), 1016 (s), 1001 (s), 744 (versus), 680 (versus), 652 (versus).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.46693 (2)	0.26144 (2)	0.035455 (16)	0.0381
Br2	0.43237 (2)	0.34439 (2)	0.473273 (16)	0.0424
Si1	0.89343 (5)	0.27797 (5)	0.27898 (4)	0.0263
O1	0.19606 (19)	0.74521 (18)	0.08105 (14)	0.0558
O2	0.1674 (2)	0.77076 (17)	0.24778 (15)	0.0597
N1	0.21456 (19)	0.70571 (19)	0.17475 (16)	0.0429
C1	0.45715 (19)	0.32075 (19)	0.25168 (15)	0.0299
C2	0.4187 (2)	0.37128 (19)	0.14612 (15)	0.0317
C3	0.3420 (2)	0.4954 (2)	0.12022 (16)	0.0337
C4	0.2966 (2)	0.5741 (2)	0.20082 (17)	0.0352
C5	0.3235 (2)	0.5303 (2)	0.30654 (17)	0.0358
C6	0.4008 (2)	0.4064 (2)	0.32948 (15)	0.0326
N7	0.52613 (18)	0.19721 (16)	0.28101 (13)	0.0332
C8	0.65370 (19)	0.14350 (18)	0.24912 (14)	0.0273
N9	0.69500 (17)	0.01358 (16)	0.27288 (13)	0.0330
C10	0.5960 (3)	−0.0593 (2)	0.3320 (2)	0.0464
C11	0.4843 (3)	−0.0965 (3)	0.2639 (3)	0.0634
C12	0.8285 (2)	−0.0630 (2)	0.23351 (17)	0.0374
C13	0.8181 (3)	−0.1014 (3)	0.1218 (2)	0.0539
C14	0.75897 (19)	0.21770 (18)	0.19558 (14)	0.0270
C15	1.0595 (2)	0.2746 (2)	0.19361 (16)	0.0339
C16	1.0342 (2)	0.3634 (2)	0.09036 (17)	0.0406
C17	1.1272 (2)	0.1355 (2)	0.1689 (2)	0.0461
C18	0.8105 (2)	0.44838 (19)	0.31305 (17)	0.0382
C19	0.7249 (3)	0.5391 (2)	0.2257 (2)	0.0477
C20	0.9235 (3)	0.5178 (3)	0.3533 (3)	0.0640
C21	0.9434 (2)	0.1665 (2)	0.40418 (15)	0.0346
C22	0.8241 (3)	0.1779 (3)	0.48726 (17)	0.0540
C23	1.0865 (3)	0.1814 (3)	0.4518 (2)	0.0580
H31	0.3198	0.5278	0.0449	0.0411*
H51	0.2877	0.5874	0.3640	0.0434*
H101	0.6539	−0.1409	0.3678	0.0553*
H102	0.5448	−0.0041	0.3863	0.0553*
H111	0.4216	−0.1454	0.3094	0.0763*
H112	0.5335	−0.1528	0.2095	0.0763*
H113	0.4244	−0.0160	0.2281	0.0763*
H121	0.9051	−0.0101	0.2341	0.0446*
H122	0.8556	−0.1444	0.2820	0.0446*
H131	0.9127	−0.1529	0.1004	0.0651*
H132	0.7922	−0.0212	0.0719	0.0651*
H133	0.7427	−0.1554	0.1198	0.0651*
H141	0.8163	0.1600	0.1453	0.0325*
H142	0.7018	0.2962	0.1551	0.0325*
H151	1.1313	0.3066	0.2350	0.0409*
H161	1.1261	0.3568	0.0492	0.0489*
H162	0.9997	0.4555	0.1069	0.0489*
H163	0.9604	0.3360	0.0477	0.0489*
H171	1.2146	0.1374	0.1237	0.0539*
H172	1.1547	0.0801	0.2363	0.0539*
H173	1.0563	0.0986	0.1306	0.0539*
H181	0.7422	0.4384	0.3731	0.0459*
H191	0.6867	0.6256	0.2525	0.0569*
H192	0.7887	0.5507	0.1631	0.0569*
H193	0.6432	0.5002	0.2045	0.0569*
H201	0.8765	0.6071	0.3705	0.0786*
H202	0.9693	0.4670	0.4183	0.0786*
H203	0.9985	0.5242	0.2974	0.0786*
H211	0.9584	0.0755	0.3833	0.0417*
H221	0.8567	0.1171	0.5511	0.0615*
H222	0.8004	0.2693	0.5074	0.0615*
H223	0.7369	0.1547	0.4578	0.0615*
H231	1.1074	0.1206	0.5173	0.0712*
H232	1.0794	0.2730	0.4695	0.0712*
H233	1.1656	0.1601	0.3990	0.0712*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.03238 (10)	0.04794 (13)	0.03618 (11)	−0.00810 (8)	−0.00026 (8)	−0.01389 (9)
Br2	0.04972 (13)	0.04334 (12)	0.03271 (11)	−0.00650 (10)	0.00765 (9)	−0.00373 (8)
Si1	0.0270 (2)	0.0255 (2)	0.0269 (2)	−0.00682 (19)	−0.00300 (19)	−0.00135 (19)
O1	0.0512 (10)	0.0545 (10)	0.0532 (10)	0.0074 (8)	−0.0055 (8)	0.0036 (8)
O2	0.0668 (12)	0.0444 (10)	0.0615 (11)	0.0107 (9)	−0.0061 (9)	−0.0149 (8)
N1	0.0324 (9)	0.0409 (10)	0.0533 (11)	−0.0020 (8)	−0.0036 (8)	−0.0041 (9)
C1	0.0235 (8)	0.0333 (10)	0.0347 (9)	−0.0093 (7)	0.0054 (7)	−0.0058 (8)
C2	0.0249 (9)	0.0373 (10)	0.0351 (10)	−0.0091 (8)	0.0030 (7)	−0.0093 (8)
C3	0.0251 (9)	0.0401 (11)	0.0369 (10)	−0.0086 (8)	−0.0007 (7)	−0.0039 (8)
C4	0.0257 (9)	0.0333 (10)	0.0461 (11)	−0.0041 (8)	−0.0024 (8)	−0.0050 (8)
C5	0.0300 (9)	0.0387 (11)	0.0398 (10)	−0.0070 (8)	0.0032 (8)	−0.0099 (8)
C6	0.0287 (9)	0.0364 (10)	0.0331 (9)	−0.0074 (8)	0.0051 (7)	−0.0050 (8)
N7	0.0318 (8)	0.0317 (8)	0.0368 (9)	−0.0080 (7)	0.0076 (7)	−0.0044 (7)
C8	0.0294 (9)	0.0286 (9)	0.0258 (8)	−0.0095 (7)	−0.0003 (7)	−0.0046 (7)
N9	0.0331 (8)	0.0283 (8)	0.0379 (9)	−0.0073 (7)	0.0035 (7)	−0.0027 (7)
C10	0.0451 (12)	0.0334 (11)	0.0602 (14)	−0.0131 (9)	0.0056 (10)	0.0082 (10)
C11	0.0415 (13)	0.0460 (14)	0.104 (2)	−0.0170 (11)	−0.0043 (14)	0.0043 (14)
C12	0.0378 (11)	0.0313 (10)	0.0419 (11)	−0.0017 (8)	−0.0015 (9)	−0.0072 (8)
C13	0.0522 (14)	0.0549 (15)	0.0562 (15)	−0.0046 (11)	−0.0003 (11)	−0.0249 (12)
C14	0.0257 (8)	0.0305 (9)	0.0258 (8)	−0.0079 (7)	−0.0008 (7)	−0.0028 (7)
C15	0.0272 (9)	0.0399 (11)	0.0353 (10)	−0.0104 (8)	−0.0042 (7)	0.0021 (8)
C16	0.0356 (10)	0.0478 (12)	0.0377 (11)	−0.0113 (9)	0.0009 (8)	0.0050 (9)
C17	0.0328 (11)	0.0440 (12)	0.0576 (14)	−0.0015 (9)	0.0110 (10)	−0.0009 (10)
C18	0.0462 (12)	0.0287 (10)	0.0400 (11)	−0.0073 (9)	0.0018 (9)	−0.0047 (8)
C19	0.0434 (12)	0.0283 (10)	0.0696 (16)	−0.0031 (9)	−0.0100 (11)	−0.0003 (10)
C20	0.0791 (19)	0.0387 (13)	0.0777 (19)	−0.0100 (13)	−0.0313 (15)	−0.0180 (12)
C21	0.0431 (11)	0.0322 (10)	0.0287 (9)	−0.0080 (8)	−0.0065 (8)	−0.0016 (8)
C22	0.0712 (17)	0.0546 (15)	0.0271 (10)	0.0062 (12)	0.0065 (10)	0.0022 (10)
C23	0.0707 (17)	0.0535 (15)	0.0535 (14)	−0.0228 (13)	−0.0350 (13)	0.0082 (12)

Geometric parameters (Å, º)

Br1—C2	1.8959 (19)	C13—H131	1.000
Br2—C6	1.893 (2)	C13—H132	1.000
Si1—C14	1.9185 (18)	C13—H133	1.000
Si1—C15	1.888 (2)	C14—H141	1.000
Si1—C18	1.897 (2)	C14—H142	1.000
Si1—C21	1.898 (2)	C15—C16	1.533 (3)
O1—N1	1.229 (3)	C15—C17	1.537 (3)
O2—N1	1.229 (3)	C15—H151	1.000
N1—C4	1.461 (3)	C16—H161	1.000
C1—C2	1.426 (3)	C16—H162	1.000
C1—C6	1.425 (3)	C16—H163	1.000
C1—N7	1.358 (3)	C17—H171	1.000
C2—C3	1.379 (3)	C17—H172	1.000
C3—C4	1.387 (3)	C17—H173	1.000
C3—H31	1.000	C18—C19	1.532 (3)
C4—C5	1.393 (3)	C18—C20	1.536 (3)
C5—C6	1.374 (3)	C18—H181	1.000
C5—H51	1.000	C19—H191	1.000
N7—C8	1.305 (2)	C19—H192	1.000
C8—N9	1.353 (2)	C19—H193	1.000
C8—C14	1.498 (2)	C20—H201	1.000
N9—C10	1.474 (3)	C20—H202	1.000
N9—C12	1.467 (3)	C20—H203	1.000
C10—C11	1.519 (4)	C21—C22	1.525 (3)
C10—H101	1.000	C21—C23	1.545 (3)
C10—H102	1.000	C21—H211	1.000
C11—H111	1.000	C22—H221	1.000
C11—H112	1.000	C22—H222	1.000
C11—H113	1.000	C22—H223	1.000
C12—C13	1.525 (3)	C23—H231	1.000
C12—H121	1.000	C23—H232	1.000
C12—H122	1.000	C23—H233	1.000
C14—Si1—C15	105.53 (8)	C8—C14—H141	106.9
C14—Si1—C18	108.26 (9)	Si1—C14—H141	106.9
C15—Si1—C18	112.37 (9)	C8—C14—H142	106.9
C14—Si1—C21	112.01 (8)	Si1—C14—H142	106.9
C15—Si1—C21	108.45 (9)	H141—C14—H142	109.5
C18—Si1—C21	110.17 (9)	Si1—C15—C16	113.71 (14)
O1—N1—O2	123.6 (2)	Si1—C15—C17	111.66 (14)
O1—N1—C4	118.30 (19)	C16—C15—C17	109.52 (18)
O2—N1—C4	118.15 (19)	Si1—C15—H151	107.2
C2—C1—C6	114.13 (18)	C16—C15—H151	107.3
C2—C1—N7	125.02 (17)	C17—C15—H151	107.1
C6—C1—N7	120.40 (18)	C15—C16—H161	109.5
Br1—C2—C1	119.08 (14)	C15—C16—H162	109.4
Br1—C2—C3	117.60 (15)	H161—C16—H162	109.5
C1—C2—C3	123.26 (18)	C15—C16—H163	109.6
C2—C3—C4	118.59 (19)	H161—C16—H163	109.5
C2—C3—H31	120.6	H162—C16—H163	109.5
C4—C3—H31	120.8	C15—C17—H171	109.5
N1—C4—C3	119.28 (19)	C15—C17—H172	109.5
N1—C4—C5	118.82 (19)	H171—C17—H172	109.5
C3—C4—C5	121.88 (19)	C15—C17—H173	109.4
C4—C5—C6	117.97 (19)	H171—C17—H173	109.5
C4—C5—H51	121.0	H172—C17—H173	109.5
C6—C5—H51	121.0	Si1—C18—C19	116.55 (15)
Br2—C6—C1	117.85 (15)	Si1—C18—C20	111.50 (16)
Br2—C6—C5	118.13 (15)	C19—C18—C20	108.25 (19)
C1—C6—C5	124.01 (19)	Si1—C18—H181	106.7
C1—N7—C8	125.59 (16)	C19—C18—H181	106.8
N7—C8—N9	116.91 (17)	C20—C18—H181	106.5
N7—C8—C14	124.15 (17)	C18—C19—H191	109.4
N9—C8—C14	118.79 (16)	C18—C19—H192	109.6
C8—N9—C10	119.40 (17)	H191—C19—H192	109.5
C8—N9—C12	123.41 (16)	C18—C19—H193	109.4
C10—N9—C12	116.87 (17)	H191—C19—H193	109.5
N9—C10—C11	114.2 (2)	H192—C19—H193	109.5
N9—C10—H101	108.3	C18—C20—H201	109.5
C11—C10—H101	108.4	C18—C20—H202	109.5
N9—C10—H102	108.3	H201—C20—H202	109.5
C11—C10—H102	108.2	C18—C20—H203	109.4
H101—C10—H102	109.5	H201—C20—H203	109.5
C10—C11—H111	109.4	H202—C20—H203	109.5
C10—C11—H112	109.4	Si1—C21—C22	113.20 (15)
H111—C11—H112	109.5	Si1—C21—C23	113.10 (15)
C10—C11—H113	109.6	C22—C21—C23	111.0 (2)
H111—C11—H113	109.5	Si1—C21—H211	106.3
H112—C11—H113	109.5	C22—C21—H211	106.3
N9—C12—C13	113.95 (18)	C23—C21—H211	106.4
N9—C12—H121	108.2	C21—C22—H221	109.4
C13—C12—H121	108.4	C21—C22—H222	109.5
N9—C12—H122	108.5	H221—C22—H222	109.5
C13—C12—H122	108.4	C21—C22—H223	109.5
H121—C12—H122	109.5	H221—C22—H223	109.5
C12—C13—H131	109.4	H222—C22—H223	109.5
C12—C13—H132	109.5	C21—C23—H231	109.6
H131—C13—H132	109.5	C21—C23—H232	109.5
C12—C13—H133	109.5	H231—C23—H232	109.5
H131—C13—H133	109.5	C21—C23—H233	109.2
H132—C13—H133	109.5	H231—C23—H233	109.5
C8—C14—Si1	119.51 (12)	H232—C23—H233	109.5