4-Methyl­phenyl (dimethyl­amido)­(isopropyl­amido)­phosphate

In the title compound, C₁₂H₂₁N₂O₂P, the P—N bond lengths of 1.617 (2) and 1.645 (3) Å are shorter than a normal P—N single bond. The sum of the bond angles around the phospho­ramide N atoms of 353° indicates their sp²-hybridization. Mol­ecules are linked via N—H...O=P hydrogen bonds into a one-dimensional chain parallel to the c axis.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.057
• wR factor = 0.093
• Data-to-parameter ratio = 18.0

checkCIF/PLATON results

No syntax errors found



Alert level C
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.107
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.11
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of P1     = ...          R

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Acetylcholinesterase (AChE) enzyme inhibition by organophosphorus (OPs) compounds is well known (Ekstrom et al., 2006). It is generally governed by intramolecular properties (lipophilicity, electronic, steric) and three-dimensional structure of OPs (Singh, 1999). The range of herbicides which can be derived from OPs is very large indeed. For example, Amiprofos-methyl [O-methyl O-(4-methyl-2-nitrophenyl) N-isopropyl phosphoramidothioate] is a herbicidal organophosphate (Fest & Schmidt, 1982). In our previous work, we reported on the structure of N,N-dimethyl O-p-tolyl phosphoramidocyanidate (Ghadimi et al., 2007). Here, we report the synthesis and crystal structure of the title compound. The four different groups linked to P atom give rise to a distorted tetrahedral configuration (Figure 1). The bond angles around P atom are in the range of 102.76 (14)° [for O2—P1—N2 amgle] to 114.77 (14)° [for the O1—P1—N2 angle]. The P1—O2 bond length [1.607 (2) Å] is shorter than the P—O single bond length (1.64 Å; Corbridge, 1995). Also, the P—N bond lengths [P1—N1 = 1.645 (3) Å and P1—N2 = 1.617 (2) Å] are shorter than the P—N single bond length (1.77 Å; Corbridge, 1995). The sum of the surrounding angles around N1 nad N2 (about 353°) points to sp² hybridization for the nitrogen atoms. Molecules are linked via N—H···O=P hydrogen bonds (Table 1, Fig. 2|) into one-dimensional chains parallel to the c axis.

Related literature

For related literature, see: Corbridge (1995); Ekstrom et al. (2006); Fest & Schmidt (1982); Ghadimi et al. (2007); Singh (1999).

S2. Experimental

To a solution of N,N-dimethyl phosphoramidochloridic acid 4-methyl phenyl ester (0.82 g, 3.51 mmol) in 30 ml dry chloroform, isoprophylamine (0.41 g, 7.02 mmol) was added slowly and solution stirred at 273 K for 5 h. The solvent was evaporated in vacuum. Then the product was washed with water to remove [(CH₃)₂CHNH₃]Cl. After drying, the product was crystallized from chloroform at room temperature.

S3. Refinement

The H atom of the NH group was found in a difference Fourier map and the remaining H atoms were placed in calculated positions. They were refined in riding model approximation with U_iso(H) = 1.2U_eq(N,C) or 1.5U_eq(C) for methyl groups.

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005; data reduction: APEX2 (Bruker, 2005; program(s) used to solve structure: SHELXTL (Bruker, 1998); program(s) used to refine structure: SHELXTL (Bruker, 1998); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL (Bruker, 1998).

Figures

	Fig. 1. The molecular structure of title compound showing the atom-numbering scheme. All non-H atoms are represented by 40% probability displacement ellipsoids.
	Fig. 2. A view of crystal packing of the title compound

4-Methylphenyl (dimethylamido)(isopropylamido)phosphate

Crystal data

C12H21N2O2P	F(000) = 552
Mr = 256.28	Dx = 1.203 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 16.711 (5) Å	Cell parameters from 498 reflections
b = 8.306 (2) Å	θ = 3–20°
c = 10.425 (3) Å	µ = 0.19 mm^−1
β = 101.963 (9)°	T = 100 K
V = 1415.6 (7) Å^3	Needle, colorless
Z = 4	0.21 × 0.09 × 0.08 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer	2779 independent reflections
Radiation source: fine-focus sealed tube	1418 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.107
Detector resolution: 0 pixels mm^-1	θmax = 26.0°, θmin = 1.3°
π and ω scans	h = −20→19
Absorption correction: multi-scan (APEX2; Bruker, 2005)	k = −10→8
Tmin = 0.963, Tmax = 0.987	l = −12→12
6264 measured reflections

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)] = 0.057	Hydrogen site location: mixed
wR(F^2) = 0.093	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.01P)^2 + 0.01P] where P = (Fo^2 + 2Fc^2)/3
2779 reflections	(Δ/σ)max < 0.001
154 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

Special details

Experimental. ¹H NMR (CDCl₃, p.p.m.): 1.12 (d, 3H, ³J_H—H = 6.5 Hz, isopropylamine-CH₃), 1.15 (d, 3H, ³J_H—H = 6.4 Hz, isopropylamine-CH₃), 2.25 (s, 3 H, p-CH₃), 2.33 (b, 1H, NH), 2.68 (d, ³J_PNCH = 10.1 Hz, 6H, N(CH₃)₂), 3.38–3.39 (m, 1H, isopropylamine-CH), 7.03 (m, 4 H, Ar—H); ¹³C NMR (CDCl₃, p.p.m.): 20.64 (s, 1 C, p-CH₃), 25.27 (d, ³J_P—C = 5.9 Hz, 1 C, isopropylamine-CH₃), 25.52 (d, ³J_P—C = 5.3 Hz, 1 C, isopropylamine-CH₃), 36.96 (d, ²J_P—C = 3.8 Hz, 2 C, N(CH₃)₂), 43.38 (s, 1 C, isopropylamine-CH), 119.92 (d, ³J_P—C = 4.8 Hz, 2 C, C_ortho), 129.96 (s, 2 C, C_meta), 133.50 (s, 1 C, C_para), 149.12 (d, ²J_P—C = 6.1 Hz, 1 C, C_ipso); ³¹P{¹H} NMR (CDCl₃, p.p.m.): 13.70 (s); ³¹P NMR (CDCl₃, p.p.m.): 13.70 (m). IR (KBr, cm^-1): 3210, 2949, 2940, 1599, 1499, 1455, 1297, 1227 (P=O), 1198, 1162, 1040, 985, 906, 816, 794, 705.

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
P1	0.21748 (6)	0.33403 (11)	0.82100 (9)	0.0181 (2)
O1	0.20364 (14)	0.3011 (2)	0.6793 (2)	0.0226 (6)
O2	0.30994 (14)	0.3037 (2)	0.8981 (2)	0.0179 (6)
N1	0.20238 (18)	0.5259 (3)	0.8471 (3)	0.0209 (7)
N2	0.16505 (16)	0.2225 (3)	0.9006 (3)	0.0178 (7)
H2	0.1838	0.2190	0.9885	0.021*
C1	0.2200 (2)	0.6460 (4)	0.7554 (4)	0.0310 (10)
H1A	0.1838	0.7389	0.7552	0.047*
H1B	0.2109	0.5995	0.6671	0.047*
H1C	0.2771	0.6807	0.7819	0.047*
C2	0.2109 (2)	0.5839 (4)	0.9817 (4)	0.0295 (10)
H2A	0.1754	0.6776	0.9827	0.044*
H2B	0.2679	0.6147	1.0163	0.044*
H2C	0.1951	0.4983	1.0362	0.044*
C3	0.0771 (2)	0.1973 (4)	0.8552 (3)	0.0226 (9)
H3A	0.0621	0.2266	0.7602	0.027*
C4	0.0277 (2)	0.3017 (4)	0.9294 (3)	0.0318 (10)
H4A	−0.0307	0.2786	0.8989	0.048*
H4B	0.0380	0.4155	0.9139	0.048*
H4C	0.0437	0.2786	1.0235	0.048*
C5	0.0583 (2)	0.0194 (4)	0.8689 (4)	0.0374 (12)
H5A	0.0879	−0.0446	0.8149	0.056*
H5B	−0.0006	0.0013	0.8398	0.056*
H5C	0.0755	−0.0130	0.9609	0.056*
C6	0.3447 (2)	0.1490 (4)	0.9015 (3)	0.0175 (8)
C7	0.3480 (2)	0.0556 (4)	1.0113 (3)	0.0205 (9)
H7A	0.3250	0.0934	1.0818	0.025*
C8	0.3849 (2)	−0.0936 (4)	1.0182 (4)	0.0232 (9)
H8A	0.3865	−0.1587	1.0936	0.028*
C9	0.4196 (2)	−0.1501 (4)	0.9174 (3)	0.0207 (8)
C10	0.4153 (2)	−0.0534 (4)	0.8082 (4)	0.0234 (9)
H10A	0.4384	−0.0905	0.7378	0.028*
C11	0.3777 (2)	0.0973 (4)	0.7989 (4)	0.0216 (9)
H11A	0.3751	0.1625	0.7232	0.026*
C12	0.4589 (2)	−0.3151 (4)	0.9248 (4)	0.0292 (9)
H12A	0.4816	−0.3330	0.8466	0.044*
H12B	0.4176	−0.3975	0.9295	0.044*
H12C	0.5028	−0.3215	1.0032	0.044*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0254 (6)	0.0142 (4)	0.0153 (5)	−0.0006 (5)	0.0058 (4)	0.0004 (5)
O1	0.0359 (16)	0.0207 (13)	0.0121 (13)	−0.0013 (11)	0.0068 (12)	0.0009 (11)
O2	0.0202 (14)	0.0117 (11)	0.0206 (14)	0.0012 (10)	0.0014 (11)	−0.0038 (11)
N1	0.033 (2)	0.0132 (14)	0.0159 (18)	0.0009 (14)	0.0048 (16)	0.0028 (14)
N2	0.0220 (18)	0.0200 (14)	0.0118 (16)	−0.0046 (13)	0.0039 (14)	0.0012 (13)
C1	0.043 (3)	0.0160 (17)	0.034 (2)	−0.0009 (19)	0.007 (2)	0.0012 (19)
C2	0.039 (3)	0.0219 (18)	0.029 (2)	0.0020 (18)	0.010 (2)	−0.0100 (18)
C3	0.023 (2)	0.028 (2)	0.017 (2)	−0.0006 (18)	0.0033 (18)	0.0026 (17)
C4	0.030 (2)	0.036 (2)	0.030 (2)	0.000 (2)	0.008 (2)	−0.001 (2)
C5	0.037 (3)	0.027 (2)	0.050 (3)	−0.0136 (19)	0.014 (3)	−0.013 (2)
C6	0.017 (2)	0.0136 (17)	0.023 (2)	0.0033 (16)	0.0056 (17)	−0.0037 (18)
C7	0.027 (2)	0.0175 (18)	0.018 (2)	−0.0015 (17)	0.0075 (18)	−0.0054 (17)
C8	0.026 (2)	0.0178 (18)	0.025 (2)	−0.0033 (17)	0.0036 (19)	0.0023 (17)
C9	0.020 (2)	0.0163 (17)	0.026 (2)	0.0027 (17)	0.0057 (18)	−0.0023 (18)
C10	0.025 (2)	0.028 (2)	0.019 (2)	0.0005 (17)	0.0089 (19)	−0.0066 (18)
C11	0.030 (2)	0.0151 (17)	0.022 (2)	0.0002 (17)	0.0086 (19)	0.0010 (17)
C12	0.030 (2)	0.0192 (19)	0.039 (2)	0.0032 (18)	0.007 (2)	−0.0010 (19)

Geometric parameters (Å, º)

P1—O1	1.473 (2)	C4—H4B	0.9800
P1—O2	1.607 (2)	C4—H4C	0.9800
P1—N2	1.617 (2)	C5—H5A	0.9800
P1—N1	1.645 (3)	C5—H5B	0.9800
O2—C6	1.408 (3)	C5—H5C	0.9800
N1—C1	1.454 (4)	C6—C11	1.370 (4)
N1—C2	1.463 (4)	C6—C7	1.375 (4)
N2—C3	1.462 (4)	C7—C8	1.379 (4)
N2—H2	0.9055	C7—H7A	0.9500
C1—H1A	0.9800	C8—C9	1.384 (4)
C1—H1B	0.9800	C8—H8A	0.9500
C1—H1C	0.9800	C9—C10	1.383 (4)
C2—H2A	0.9800	C9—C12	1.514 (4)
C2—H2B	0.9800	C10—C11	1.394 (4)
C2—H2C	0.9800	C10—H10A	0.9500
C3—C4	1.517 (4)	C11—H11A	0.9500
C3—C5	1.524 (4)	C12—H12A	0.9800
C3—H3A	1.0000	C12—H12B	0.9800
C4—H4A	0.9800	C12—H12C	0.9800
O1—P1—O2	114.03 (13)	C3—C4—H4C	109.5
O1—P1—N2	114.77 (14)	H4A—C4—H4C	109.5
O2—P1—N2	102.76 (14)	H4B—C4—H4C	109.5
O1—P1—N1	110.38 (14)	C3—C5—H5A	109.5
O2—P1—N1	103.52 (14)	C3—C5—H5B	109.5
N2—P1—N1	110.63 (13)	H5A—C5—H5B	109.5
C6—O2—P1	120.3 (2)	C3—C5—H5C	109.5
C1—N1—C2	114.3 (3)	H5A—C5—H5C	109.5
C1—N1—P1	119.8 (2)	H5B—C5—H5C	109.5
C2—N1—P1	119.4 (2)	C11—C6—C7	121.4 (3)
C3—N2—P1	122.1 (2)	C11—C6—O2	119.8 (3)
C3—N2—H2	115.9	C7—C6—O2	118.8 (3)
P1—N2—H2	115.2	C6—C7—C8	119.4 (3)
N1—C1—H1A	109.5	C6—C7—H7A	120.3
N1—C1—H1B	109.5	C8—C7—H7A	120.3
H1A—C1—H1B	109.5	C7—C8—C9	121.3 (3)
N1—C1—H1C	109.5	C7—C8—H8A	119.4
H1A—C1—H1C	109.5	C9—C8—H8A	119.4
H1B—C1—H1C	109.5	C10—C9—C8	118.0 (3)
N1—C2—H2A	109.5	C10—C9—C12	121.1 (3)
N1—C2—H2B	109.5	C8—C9—C12	120.9 (3)
H2A—C2—H2B	109.5	C9—C10—C11	121.7 (3)
N1—C2—H2C	109.5	C9—C10—H10A	119.2
H2A—C2—H2C	109.5	C11—C10—H10A	119.2
H2B—C2—H2C	109.5	C6—C11—C10	118.3 (3)
N2—C3—C4	111.7 (3)	C6—C11—H11A	120.8
N2—C3—C5	108.8 (3)	C10—C11—H11A	120.8
C4—C3—C5	111.2 (3)	C9—C12—H12A	109.5
N2—C3—H3A	108.3	C9—C12—H12B	109.5
C4—C3—H3A	108.3	H12A—C12—H12B	109.5
C5—C3—H3A	108.3	C9—C12—H12C	109.5
C3—C4—H4A	109.5	H12A—C12—H12C	109.5
C3—C4—H4B	109.5	H12B—C12—H12C	109.5
H4A—C4—H4B	109.5
O1—P1—O2—C6	−61.9 (2)	P1—N2—C3—C5	136.0 (2)
N2—P1—O2—C6	62.9 (2)	P1—O2—C6—C11	83.0 (3)
N1—P1—O2—C6	178.1 (2)	P1—O2—C6—C7	−99.9 (3)
O1—P1—N1—C1	−31.4 (3)	C11—C6—C7—C8	−0.3 (5)
O2—P1—N1—C1	91.1 (3)	O2—C6—C7—C8	−177.3 (3)
N2—P1—N1—C1	−159.5 (3)	C6—C7—C8—C9	0.9 (5)
O1—P1—N1—C2	178.5 (2)	C7—C8—C9—C10	−0.9 (5)
O2—P1—N1—C2	−59.1 (3)	C7—C8—C9—C12	−179.0 (3)
N2—P1—N1—C2	50.3 (3)	C8—C9—C10—C11	0.4 (5)
O1—P1—N2—C3	−48.3 (3)	C12—C9—C10—C11	178.6 (3)
O2—P1—N2—C3	−172.7 (2)	C7—C6—C11—C10	−0.1 (5)
N1—P1—N2—C3	77.4 (3)	O2—C6—C11—C10	176.9 (3)
P1—N2—C3—C4	−100.8 (3)	C9—C10—C11—C6	0.1 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O1^i	0.91	1.96	2.849 (4)	169

Symmetry code: (i) x, −y+1/2, z+1/2.