Diiso­propyl hydrazo­carboxyl­ate

The title compound, C₈H₁₆N₂O₄, is the product of a Mitsunobu coupling using the diiso­propyl­azodi­carboxyl­ate. It forms hydrogen-bonded chains similar to those in its previously reported diethyl analogue.

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.069
• wR factor = 0.143
• Data-to-parameter ratio = 14.8

checkCIF results

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ADDSYM reports no extra symmetry

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S1. Comment

The title compound, (I), was obtained as a byproduct of a Mitsunobu coupling reaction using triphenylphosphine and diisopropylazodicarboxylate as reagents. The N1—N2 bond is 1.380 (3) %A, and the two C═O bond distances are 1.216 (3) and 1.217 (4) Å. These values are in agreement with the parameters of 1.381 and 1.202/1.206 Å, respectively, reported for the 1:1 adduct of (I) with triphenylphosphine oxide (Héroux & Brisse, 1997). The torsion angle around the central N—N bond is 73.2° in the latter structure, compared with 100.4° in the title compound.

Each molecule of (I) is connected to two adjacent molecules by four N—H···O hydrogen bonds (Fig. 2 and Table 1). The hydrogen-bond linkage between two neighbouring molecules A and B involves one H-atom donor site and one acceptor site in each of them, N—H(A)···O(B) and N—H(B)···O(A). The hydrogen-bonded chains propagate parallel to [100], with N···O distances of 2.853 (3) and 2.829 (3) Å and N—H···O bond angles of 157 and 174°. A similar hydrogen-bonded one-dimensional network occurs in the diethyl analogue of (I) (Linke & Kalker, 1977).

In contrast, in the 1:1 adduct of diisopropyl hydrazocarboxylate, (I), with triphenylphosphine oxide, (II), the carbonyl O atoms do not participate in hydrogen bonding. Instead, each phosphoryl O atom of (II) is a bifurcated acceptor to the NH groups of two molecules of (I). The result is a cyclic arrangement of four molecules, two (I) + two (II) (Héroux & Brisse, 1997).

S2. Experimental

Crystals of (I) were isolated as colourless needles from CHCl₃.

Computing details

Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990).

Figures

	Fig. 1. The structure of (I) showing 50% probability displacement ellipsoids.
	Fig. 2. Projections of the crystal structure viewed along c (top) and along b showing hydrogen-bonded chains parallel to [100] (bottom).

(I)

Crystal data

C8H16N2O4	F(000) = 440
Mr = 204.23	Dx = 1.251 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.0299 (16) Å	Cell parameters from 4438 reflections
b = 12.765 (3) Å	θ = 3.0–25.0°
c = 10.587 (2) Å	µ = 0.10 mm^−1
β = 92.11 (3)°	T = 120 K
V = 1084.4 (4) Å^3	Needle, colourless
Z = 4	0.12 × 0.05 × 0.05 mm

Data collection

Nonius KappaCCD area-detector diffractometer	1890 independent reflections
Radiation source: Nonius FR591 rotating anode	1289 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.099
ϕ and ω scans to fill Ewald sphere	θmax = 25.0°, θmin = 3.0°
Absorption correction: multi-scan (Blessing, 1997)	h = −9→9
Tmin = 0.988, Tmax = 0.995	k = −15→15
4768 measured reflections	l = −12→12

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.069	H-atom parameters constrained
wR(F^2) = 0.143	w = 1/[σ^2(Fo^2) + (0.0001P)^2 + 1.7P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
1890 reflections	Δρmax = 0.51 e Å^−3
128 parameters	Δρmin = −0.32 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.014 (3)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
O1	0.2492 (2)	−0.23490 (16)	−0.0148 (2)	0.0231 (5)
O2	0.0593 (2)	−0.14300 (17)	0.0931 (2)	0.0251 (6)
O3	0.4424 (2)	0.04803 (17)	0.1561 (2)	0.0250 (6)
O4	0.2496 (2)	0.17839 (16)	0.13712 (19)	0.0205 (5)
N1	0.2581 (3)	−0.0624 (2)	−0.0204 (3)	0.0232 (6)
H1	0.3353	−0.0703	−0.0764	0.028*
N2	0.2159 (3)	0.03625 (19)	0.0211 (2)	0.0234 (7)
H2	0.1259	0.0677	−0.0102	0.028*
C1	0.2215 (5)	−0.4111 (3)	−0.0826 (4)	0.0372 (9)
H1A	0.1974	−0.3852	−0.1685	0.056*
H1B	0.1653	−0.4784	−0.0712	0.056*
H1C	0.3420	−0.4203	−0.0694	0.056*
C2	0.1907 (4)	−0.3649 (3)	0.1472 (3)	0.0323 (8)
H2A	0.1492	−0.3102	0.2030	0.048*
H2B	0.3107	−0.3743	0.1639	0.048*
H2C	0.1327	−0.4308	0.1631	0.048*
C3	0.1595 (4)	−0.3330 (2)	0.0118 (3)	0.0248 (8)
H3	0.0373	−0.3217	−0.0042	0.030*
C4	0.1791 (3)	−0.1470 (2)	0.0263 (3)	0.0193 (7)
C5	0.3136 (4)	0.0842 (2)	0.1101 (3)	0.0194 (7)
C6	0.3539 (4)	0.2462 (2)	0.2196 (3)	0.0213 (7)
H6	0.4729	0.2406	0.1957	0.026*
C7	0.3381 (4)	0.2133 (3)	0.3553 (3)	0.0284 (8)
H7A	0.3783	0.1413	0.3660	0.043*
H7B	0.2209	0.2171	0.3778	0.043*
H7C	0.4047	0.2602	0.4104	0.043*
C8	0.2918 (4)	0.3558 (3)	0.1948 (3)	0.0288 (8)
H8A	0.3049	0.3732	0.1056	0.043*
H8B	0.3562	0.4052	0.2479	0.043*
H8C	0.1738	0.3602	0.2148	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0275 (12)	0.0132 (12)	0.0288 (13)	0.0017 (9)	0.0061 (9)	0.0002 (10)
O2	0.0225 (11)	0.0290 (13)	0.0241 (12)	0.0036 (10)	0.0052 (9)	0.0037 (10)
O3	0.0219 (12)	0.0303 (14)	0.0231 (12)	0.0039 (10)	0.0024 (9)	0.0009 (10)
O4	0.0260 (11)	0.0150 (11)	0.0208 (12)	0.0023 (9)	0.0018 (9)	−0.0017 (9)
N1	0.0287 (14)	0.0149 (14)	0.0267 (15)	0.0017 (11)	0.0090 (12)	−0.0023 (12)
N2	0.0289 (14)	0.0144 (14)	0.0266 (15)	0.0049 (11)	−0.0023 (12)	−0.0063 (12)
C1	0.051 (2)	0.025 (2)	0.036 (2)	−0.0006 (17)	0.0004 (17)	−0.0032 (17)
C2	0.042 (2)	0.0226 (19)	0.032 (2)	−0.0037 (15)	−0.0008 (16)	0.0042 (16)
C3	0.0262 (16)	0.0147 (17)	0.0332 (19)	−0.0047 (13)	−0.0007 (14)	−0.0007 (14)
C4	0.0224 (16)	0.0169 (17)	0.0184 (16)	0.0019 (13)	−0.0035 (13)	−0.0010 (13)
C5	0.0227 (16)	0.0183 (17)	0.0179 (16)	−0.0008 (13)	0.0088 (13)	−0.0015 (13)
C6	0.0239 (15)	0.0212 (17)	0.0188 (17)	−0.0037 (13)	0.0021 (13)	−0.0059 (14)
C7	0.0366 (18)	0.031 (2)	0.0175 (17)	0.0023 (15)	0.0041 (14)	−0.0005 (15)
C8	0.0398 (19)	0.0225 (18)	0.0241 (18)	−0.0025 (15)	0.0030 (14)	−0.0039 (15)

Geometric parameters (Å, º)

O1—C4	1.336 (3)	C2—C3	1.503 (5)
O1—C3	1.476 (4)	C2—H2A	0.9800
O2—C4	1.216 (3)	C2—H2B	0.9800
O3—C5	1.217 (4)	C2—H2C	0.9800
O4—C5	1.342 (4)	C3—H3	1.0000
O4—C6	1.470 (4)	C6—C8	1.504 (4)
N1—C4	1.354 (4)	C6—C7	1.506 (4)
N1—N2	1.380 (3)	C6—H6	1.0000
N1—H1	0.8800	C7—H7A	0.9800
N2—C5	1.351 (4)	C7—H7B	0.9800
N2—H2	0.8800	C7—H7C	0.9800
C1—C3	1.509 (5)	C8—H8A	0.9800
C1—H1A	0.9800	C8—H8B	0.9800
C1—H1B	0.9800	C8—H8C	0.9800
C1—H1C	0.9800
C4—O1—C3	115.9 (2)	C1—C3—H3	109.2
C5—O4—C6	116.1 (2)	O2—C4—O1	125.2 (3)
C4—N1—N2	119.2 (2)	O2—C4—N1	124.7 (3)
C4—N1—H1	120.4	O1—C4—N1	110.0 (2)
N2—N1—H1	120.4	O3—C5—O4	125.5 (3)
C5—N2—N1	119.5 (3)	O3—C5—N2	124.7 (3)
C5—N2—H2	120.2	O4—C5—N2	109.7 (3)
N1—N2—H2	120.2	O4—C6—C8	105.4 (2)
C3—C1—H1A	109.5	O4—C6—C7	109.6 (2)
C3—C1—H1B	109.5	C8—C6—C7	112.8 (3)
H1A—C1—H1B	109.5	O4—C6—H6	109.6
C3—C1—H1C	109.5	C8—C6—H6	109.6
H1A—C1—H1C	109.5	C7—C6—H6	109.6
H1B—C1—H1C	109.5	C6—C7—H7A	109.5
C3—C2—H2A	109.5	C6—C7—H7B	109.5
C3—C2—H2B	109.5	H7A—C7—H7B	109.5
H2A—C2—H2B	109.5	C6—C7—H7C	109.5
C3—C2—H2C	109.5	H7A—C7—H7C	109.5
H2A—C2—H2C	109.5	H7B—C7—H7C	109.5
H2B—C2—H2C	109.5	C6—C8—H8A	109.5
O1—C3—C2	110.2 (3)	C6—C8—H8B	109.5
O1—C3—C1	105.0 (2)	H8A—C8—H8B	109.5
C2—C3—C1	113.9 (3)	C6—C8—H8C	109.5
O1—C3—H3	109.2	H8A—C8—H8C	109.5
C2—C3—H3	109.2	H8B—C8—H8C	109.5
C4—N1—N2—C5	100.2 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3^i	0.88	2.02	2.853 (3)	157
N2—H2···O2^ii	0.88	1.95	2.829 (3)	174

Symmetry codes: (i) −x+1, −y, −z; (ii) −x, −y, −z.