O,O'-Di-p-tolyl­pyrophospho­ric bis­(dimethyl­amide)

The title compound, C₁₈H₂₆N₂O₅P₂, was obtained accidently from the reaction between N,N-dimethyl­phospho­ramido­chloridic acid 4-methyl phenyl ester, NaNO₂ and 18-crown-6 in acetonitrile under reflux conditions. The asymmetric unit contains one half-mol­ecule, the complete mol­ecule being generated by crystallographic twofold symmetry, with the bridging O atom lying on the rotation axis. The P atoms exhibit a tetra­hedral coordination and are bridged via one O atom [P-O-P angle = 130.00 (19)°].

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.052
• wR factor = 0.124
• Data-to-parameter ratio = 19.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          5
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         13
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          5
PLAT927_ALERT_1_C Reported and Calculated  wR2 * 100.0 Differ by .      -0.23

Alert level G
PLAT083_ALERT_2_G SHELXL Second Parameter in WGHT Unusually Large.      16.30
PLAT960_ALERT_3_G Number of Intensities with I .LT. - 2*sig(I) ..           4
PLAT793_ALERT_4_G The Model has Chirality at P1      (Verify) ....          R

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Following our previous works about amido phosphoric acid esters with general formula [(CH₃)₂N][p-CH₃—C₆H₄—O]P(O)X [for example X = NHCH(CH₃)₂ (Pourayoubi et al., 2007) and NHC(CH₃)₃ (Ghadimi et al., 2009)], we report here on the synthesis and crystal structure of title compound, [(CH₃)₂N][p-CH₃—C₆H₄—O]P(O)(O)P(O)[O—C₆H₄-p-CH₃][N(CH₃)₂]. The asymmetric unit contains one half-molecule, the complete molecule (Fig. 1) being generated by a twofold rotation axis. The phosphorous atoms exhibit a tetrahedral coordination and are bridged via one O atom (P—O—P angle = 130.0 (2)°). The bond angles around the P atoms are in the range of 94.25 (12)° (for O1—P1—O2 angle) to 117.71 (12)° (for O3—P1—O1 angle). The nitrogen atom indicates some deviation from planarity, the sum of the surrounding angles around N atom being about 353.3°.

Related literature

For related compounds see: Ghadimi et al. (2007, 2009); Pourayoubi et al. (2007).

S2. Experimental

[(CH₃)₂N]P(O)Cl[O—C₆H₄-p-CH₃] was synthesized according to the literature method (Ghadimi et al., 2007). The title compound was prepared according to the following procedure: A mixture of [(CH₃)₂N]P(O)Cl[O—C₆H₄-p-CH₃] (0.82 g, 3.5 mmol), NaNO₂ (0.24 g, 3.5 mmol) and 18-crown-6 (0.20 g) in acetonitrile (30 ml) was refluxed for 4 h and then filtered. The solvent was removed under vacuum and the solid recrystallized in a mixture of chloroform and n-hexane to produce single crystals after a slow evaporation at room temperature. IR (KBr, cm^-1): 2995, 2900, 2880, 2820, 1850, 1580, 1480, 1440, 1300, 1235, 1250, 1185, 1100, 990, 940, 730.

S3. Refinement

The H(C) atom positions were calculated. All hydrogen atoms were refined in isotropic approximation in riding model with the Uiso(H) parameters equal to 1.2 Ueq(Ci), for methyl groups equal to 1.5 Ueq(Cii), where U(Ci) and U(Cii) are respectively the equivalent thermal parameters of the carbon atoms to which corresponding H atoms are bonded.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. Molecular view (50 % probability level) of the title compound. Symmetry code A: -x,y,-z+1/2.

O,O'-Di-p-tolylpyrophosphoric bis(dimethylamide)

Crystal data

C18H26N2O5P2	F(000) = 872
Mr = 412.35	Dx = 1.364 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1898 reflections
a = 26.484 (5) Å	θ = 2.9–30.7°
b = 7.4195 (15) Å	µ = 0.25 mm^−1
c = 11.096 (2) Å	T = 100 K
β = 112.949 (4)°	Plate, colorless
V = 2007.8 (7) Å^3	0.50 × 0.25 × 0.10 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer	2415 independent reflections
Radiation source: fine-focus sealed tube	1763 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
phi and ω scans	θmax = 28.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −34→21
Tmin = 0.930, Tmax = 0.978	k = −9→9
6483 measured reflections	l = −14→14

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.124	H-atom parameters constrained
S = 0.94	w = 1/[σ^2(Fo^2) + (0.013P)^2 + 16.2989P] where P = (Fo^2 + 2Fc^2)/3
2415 reflections	(Δ/σ)max = 0.002
126 parameters	Δρmax = 0.34 e Å^−3
0 restraints	Δρmin = −0.37 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
P1	0.05951 (3)	0.15216 (10)	0.29554 (7)	0.01597 (17)
O1	0.08997 (8)	−0.0313 (3)	0.2957 (2)	0.0188 (4)
O2	0.0000	0.0607 (4)	0.2500	0.0198 (6)
O3	0.07504 (8)	0.2488 (3)	0.4196 (2)	0.0224 (5)
N1	0.06400 (10)	0.2733 (3)	0.1781 (2)	0.0192 (5)
C1	0.14675 (11)	−0.0402 (4)	0.3240 (3)	0.0159 (6)
C2	0.18495 (13)	0.0402 (4)	0.4337 (3)	0.0237 (7)
H2A	0.1735	0.1112	0.4898	0.028*
C3	0.24040 (13)	0.0160 (4)	0.4612 (3)	0.0250 (7)
H3A	0.2669	0.0709	0.5369	0.030*
C4	0.25790 (12)	−0.0867 (4)	0.3802 (3)	0.0205 (6)
C5	0.21822 (12)	−0.1656 (4)	0.2707 (3)	0.0222 (6)
H5A	0.2294	−0.2372	0.2145	0.027*
C6	0.16261 (12)	−0.1427 (4)	0.2411 (3)	0.0205 (6)
H6A	0.1360	−0.1965	0.1652	0.025*
C7	0.31835 (12)	−0.1118 (5)	0.4103 (4)	0.0305 (8)
H7A	0.3238	−0.1263	0.3284	0.046*
H7B	0.3317	−0.2194	0.4647	0.046*
H7C	0.3387	−0.0059	0.4574	0.046*
C8	0.05658 (14)	0.4694 (4)	0.1789 (4)	0.0288 (7)
H8A	0.0723	0.5265	0.1217	0.043*
H8B	0.0751	0.5151	0.2683	0.043*
H8C	0.0174	0.4974	0.1472	0.043*
C9	0.04811 (13)	0.1948 (4)	0.0462 (3)	0.0239 (7)
H9A	0.0670	0.2590	−0.0013	0.036*
H9B	0.0084	0.2062	−0.0016	0.036*
H9C	0.0584	0.0672	0.0538	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0134 (3)	0.0175 (3)	0.0189 (4)	−0.0003 (3)	0.0084 (3)	−0.0005 (3)
O1	0.0150 (10)	0.0186 (10)	0.0268 (11)	−0.0006 (8)	0.0127 (9)	−0.0007 (9)
O2	0.0159 (14)	0.0197 (15)	0.0274 (16)	0.000	0.0123 (13)	0.000
O3	0.0209 (11)	0.0254 (11)	0.0212 (11)	0.0015 (9)	0.0087 (9)	−0.0031 (9)
N1	0.0183 (12)	0.0189 (12)	0.0216 (13)	−0.0024 (10)	0.0090 (11)	0.0008 (10)
C1	0.0142 (13)	0.0140 (12)	0.0219 (15)	−0.0007 (11)	0.0097 (11)	0.0043 (11)
C2	0.0247 (16)	0.0254 (15)	0.0223 (16)	0.0021 (13)	0.0104 (13)	−0.0029 (13)
C3	0.0200 (15)	0.0249 (15)	0.0247 (17)	−0.0016 (13)	0.0029 (13)	−0.0023 (13)
C4	0.0177 (14)	0.0172 (13)	0.0276 (16)	0.0010 (11)	0.0098 (13)	0.0077 (12)
C5	0.0208 (15)	0.0224 (15)	0.0266 (16)	0.0028 (12)	0.0127 (13)	−0.0007 (13)
C6	0.0206 (14)	0.0200 (14)	0.0221 (15)	−0.0004 (12)	0.0096 (12)	−0.0033 (12)
C7	0.0168 (15)	0.0286 (17)	0.042 (2)	0.0034 (13)	0.0075 (14)	0.0097 (15)
C8	0.0291 (17)	0.0205 (15)	0.0381 (19)	−0.0004 (13)	0.0147 (15)	0.0045 (14)
C9	0.0241 (15)	0.0279 (16)	0.0221 (16)	−0.0029 (13)	0.0115 (13)	0.0008 (13)

Geometric parameters (Å, º)

P1—O3	1.462 (2)	C4—C5	1.388 (4)
P1—O1	1.582 (2)	C4—C7	1.514 (4)
P1—O2	1.6059 (14)	C5—C6	1.389 (4)
P1—N1	1.625 (3)	C5—H5A	0.9500
O1—C1	1.413 (3)	C6—H6A	0.9500
O2—P1^i	1.6059 (14)	C7—H7A	0.9800
N1—C8	1.468 (4)	C7—H7B	0.9800
N1—C9	1.476 (4)	C7—H7C	0.9800
C1—C6	1.379 (4)	C8—H8A	0.9800
C1—C2	1.379 (4)	C8—H8B	0.9800
C2—C3	1.390 (4)	C8—H8C	0.9800
C2—H2A	0.9500	C9—H9A	0.9800
C3—C4	1.389 (4)	C9—H9B	0.9800
C3—H3A	0.9500	C9—H9C	0.9800
O3—P1—O1	117.71 (12)	C4—C5—H5A	119.1
O3—P1—O2	112.64 (10)	C6—C5—H5A	119.1
O1—P1—O2	94.25 (12)	C1—C6—C5	118.7 (3)
O3—P1—N1	113.71 (13)	C1—C6—H6A	120.6
O1—P1—N1	106.27 (12)	C5—C6—H6A	120.6
O2—P1—N1	110.55 (11)	C4—C7—H7A	109.5
C1—O1—P1	122.57 (17)	C4—C7—H7B	109.5
P1—O2—P1^i	130.00 (19)	H7A—C7—H7B	109.5
C8—N1—C9	114.2 (3)	C4—C7—H7C	109.5
C8—N1—P1	119.4 (2)	H7A—C7—H7C	109.5
C9—N1—P1	119.7 (2)	H7B—C7—H7C	109.5
C6—C1—C2	121.2 (3)	N1—C8—H8A	109.5
C6—C1—O1	116.9 (3)	N1—C8—H8B	109.5
C2—C1—O1	121.8 (3)	H8A—C8—H8B	109.5
C1—C2—C3	119.1 (3)	N1—C8—H8C	109.5
C1—C2—H2A	120.5	H8A—C8—H8C	109.5
C3—C2—H2A	120.5	H8B—C8—H8C	109.5
C4—C3—C2	121.3 (3)	N1—C9—H9A	109.5
C4—C3—H3A	119.4	N1—C9—H9B	109.5
C2—C3—H3A	119.4	H9A—C9—H9B	109.5
C5—C4—C3	117.9 (3)	N1—C9—H9C	109.5
C5—C4—C7	121.0 (3)	H9A—C9—H9C	109.5
C3—C4—C7	121.0 (3)	H9B—C9—H9C	109.5
C4—C5—C6	121.8 (3)
O3—P1—O1—C1	−64.5 (2)	P1—O1—C1—C6	−133.6 (2)
O2—P1—O1—C1	177.1 (2)	P1—O1—C1—C2	50.4 (3)
N1—P1—O1—C1	64.3 (2)	C6—C1—C2—C3	−0.4 (5)
O3—P1—O2—P1^i	66.93 (11)	O1—C1—C2—C3	175.5 (3)
O1—P1—O2—P1^i	−170.64 (9)	C1—C2—C3—C4	0.2 (5)
N1—P1—O2—P1^i	−61.51 (10)	C2—C3—C4—C5	−0.3 (5)
O3—P1—N1—C8	−28.6 (3)	C2—C3—C4—C7	179.7 (3)
O1—P1—N1—C8	−159.7 (2)	C3—C4—C5—C6	0.5 (5)
O2—P1—N1—C8	99.2 (2)	C7—C4—C5—C6	−179.4 (3)
O3—P1—N1—C9	−178.3 (2)	C2—C1—C6—C5	0.7 (4)
O1—P1—N1—C9	50.6 (2)	O1—C1—C6—C5	−175.4 (3)
O2—P1—N1—C9	−50.4 (3)	C4—C5—C6—C1	−0.7 (5)

Symmetry code: (i) −x, y, −z+1/2.