(3S,8S)-3,8-Di­methyl-1,6-dioxa-4,9-di­aza-5λ⁵-phospha­spiro­[4.4]­nonane-2,7-dione

In the the title compound, C₆H₁₁N₂O₄P, the P atom and the attached H atom lie on a crystallographic twofold axis. The mol­ecule adopts a slightly distorted trigonal bipyramidal structure. The crystal structure involves intermolecular N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.068
• wR factor = 0.198
• Data-to-parameter ratio = 9.2

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT052_ALERT_1_A (Proper) Absorption Correction Method Missing ..          ?

Alert level C
PLAT031_ALERT_4_C Refined Extinction Parameter within Range ......       2.50 Sigma
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.06
PLAT322_ALERT_2_C Check Hybridisation of  P      in Main Residue .          ?
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          9
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #          3
            O1  -P   -O1  -C2     59.40  0.50   3.755   1.555   1.555   1.555

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           26.48
           From the CIF: _reflns_number_total                570
           Count of symmetry unique reflns          575
           Completeness (_total/calc)             99.13%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present          yes

   1 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1988); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

3,8-Dimethyl-1,6-dioxa-4,9-diaza-5λ⁵-phosphaspiro[4.4]nonane-2,7-dione

Crystal data

C6H11N2O4P	F(000) = 432
Mr = 206.14	Dx = 1.468 Mg m^−3
Orthorhombic, C2221	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2c 2	Cell parameters from 25 reflections
a = 6.1138 (12) Å	θ = 8–15°
b = 7.6933 (15) Å	µ = 0.28 mm^−1
c = 19.824 (4) Å	T = 293 K
V = 932.4 (3) Å^3	Chunk, colorless
Z = 4	0.15 × 0.10 × 0.08 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	430 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.000
Graphite monochromator	θmax = 26.5°, θmin = 2.1°
ω–2θ scans	h = −7→0
Absorption correction: ψ scan (North et al., 1968)	k = 0→9
Tmin = 0.959, Tmax = 0.978	l = −24→0
570 measured reflections	3 standard reflections every 60 min
570 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.069	w = 1/[σ^2(Fo^2) + (0.1249P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.198	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.47 e Å^−3
570 reflections	Δρmin = −0.55 e Å^−3
62 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.010 (4)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 0 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.05 (6)

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
P	1.0000	0.7364 (3)	0.2500	0.0430 (7)
O1	0.7388 (7)	0.7392 (8)	0.2140 (2)	0.0529 (12)
O2	0.5527 (8)	0.8415 (8)	0.1265 (2)	0.0664 (16)
N1	1.0942 (9)	0.8294 (8)	0.1826 (3)	0.0511 (15)
H1D	1.2321	0.8486	0.1783	0.061*
C3	0.9435 (10)	0.8801 (9)	0.1293 (3)	0.0491 (17)
H3	0.9424	1.0070	0.1249	0.059*
C1	0.9974 (16)	0.7987 (13)	0.0619 (3)	0.079 (2)
H1A	1.1376	0.8393	0.0469	0.119*
H1B	0.8878	0.8305	0.0295	0.119*
H1C	1.0009	0.6745	0.0665	0.119*
C2	0.7234 (12)	0.8184 (9)	0.1556 (3)	0.0475 (16)
H	1.0000	0.542 (12)	0.2500	0.057*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P	0.0309 (11)	0.0424 (12)	0.0557 (13)	0.000	0.0066 (10)	0.000
O1	0.032 (2)	0.064 (3)	0.062 (2)	−0.010 (2)	0.006 (2)	0.001 (2)
O2	0.033 (3)	0.095 (4)	0.070 (3)	−0.012 (3)	−0.002 (2)	0.000 (3)
N1	0.031 (3)	0.070 (4)	0.052 (3)	−0.015 (3)	0.005 (2)	−0.007 (3)
C3	0.037 (4)	0.053 (4)	0.057 (4)	−0.009 (3)	0.005 (3)	0.007 (3)
C1	0.061 (5)	0.119 (7)	0.058 (4)	−0.009 (7)	0.003 (4)	−0.011 (4)
C2	0.040 (3)	0.047 (3)	0.056 (3)	−0.002 (3)	0.006 (3)	−0.005 (3)

Geometric parameters (Å, º)

P—N1	1.622 (5)	C3—C1	1.511 (9)
P—O1	1.750 (5)	C3—C2	1.520 (9)
P—H	1.49 (9)	C3—H3	0.9800
O1—C2	1.310 (8)	C1—H1A	0.9600
O2—C2	1.206 (9)	C1—H1B	0.9600
N1—C3	1.455 (9)	C1—H1C	0.9600
N1—H1D	0.8600
N1^i—P—N1	127.6 (4)	C1—C3—C2	111.6 (6)
N1—P—O1^i	90.4 (2)	N1—C3—H3	109.6
N1—P—O1	89.0 (3)	C1—C3—H3	109.6
O1^i—P—O1	178.6 (4)	C2—C3—H3	109.6
N1^i—P—H	116.2 (2)	C3—C1—H1A	109.5
N1—P—H	116.2 (2)	C3—C1—H1B	109.5
O1^i—P—H	90.7 (2)	H1A—C1—H1B	109.5
O1—P—H	90.7 (2)	C3—C1—H1C	109.5
C2—O1—P	115.6 (4)	H1A—C1—H1C	109.5
C3—N1—P	119.5 (4)	H1B—C1—H1C	109.5
C3—N1—H1D	120.3	O2—C2—O1	123.6 (6)
P—N1—H1D	120.3	O2—C2—C3	123.8 (6)
N1—C3—C1	113.1 (6)	O1—C2—C3	112.6 (6)
N1—C3—C2	103.1 (5)
N1^i—P—O1—C2	123.2 (5)	P—N1—C3—C2	−1.8 (7)
N1—P—O1—C2	−4.4 (5)	P—O1—C2—O2	−174.9 (6)
O1^i—P—O1—C2	59.4 (5)	P—O1—C2—C3	4.2 (7)
N1^i—P—N1—C3	−86.2 (5)	N1—C3—C2—O2	177.5 (7)
O1^i—P—N1—C3	−175.2 (5)	C1—C3—C2—O2	−60.8 (9)
O1—P—N1—C3	3.5 (6)	N1—C3—C2—O1	−1.6 (7)
P—N1—C3—C1	−122.5 (6)	C1—C3—C2—O1	120.1 (7)

Symmetry code: (i) −x+2, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1D···O2^ii	0.86	2.21	3.017 (7)	155

Symmetry code: (ii) x+1, y, z.