The typical crystal structures of a few representative α-aryl-α-hydroxyphosphonates

research paper s

The typical crystal structures of a few representa-

tive a-aryl-a-hydroxyphosphonates

ISSN 2053-2296

a

Zita Radai, Nora Zsuzsa Kiss, Matyas Czugler,^a,b* Konstantin Karaghiosoff^cand

´

´ ´

Gyorgy Keglevich^a

¨

^aDepartment of Organic Chemistry and Technology, Budapest University of Technology and Economics, Budapest 1521,

Hungary, ^bResearch Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest 1525, Hungary, and

^cDepartment Chemie und Biochemie, Ludwig Maximilians Universitat, Munchen 81377, Germany. *Correspondence

Received 3 January 2019

Accepted 31 January 2019

¨

e-mail: czugler.matyas@mail.bme.hu1845720184572118457221845723184572418457251845726

Edited by M. Kubicki, Adam Mickiewicz

University, Poland

The crystal structures of seven ꢀ-aryl-ꢀ-hydroxyphosphonates synthesized by

the Pudovik reaction of substituted benzaldehydes and dialkyl phosphites,

namely dimethyl [(hydroxy)(phenyl)methyl]phosphonate, C₉H₁₃O₄P, dimethyl

[(3,4-dimethoxyphenyl)(hydroxy)methyl]phosphonate, C₁₁H₁₇O₆P, dimethyl

(1-hydroxy-1-phenylethyl)phosphonate, C₁₀H₁₅O₄P, dimethyl [1-hydroxy-1-(4-

nitrophenyl)ethyl]phosphonate, C₁₀H₁₄NO₆P, dibenzyl [hydroxy(2-nitrophenyl)-

methyl]phosphonate, C₂₁H₂₀NO₆P, dibenzyl [(3-chlorophenyl)(hydroxy)methyl]-

phosphonate, C₂₁H₂₀ClO₄P, and dibenzyl [hydroxy(4-methylphenyl)methyl]-

phosphonate, C₂₂H₂₃O₄P, were studied to gain a better understanding of the

organization in this type of molecule in the solid state. The crystals obtained for

this series of compounds show a balance between C—OHꢀ ꢀ ꢀO P chain-linked

packing and the dimeric types of hydrogen-bond bridges of intermolecular pairs

of such functions. The description is based on primary graph-set descriptors.

Using graph-set descriptors one level deeper (i.e. secondary graph sets of the

C—Hꢀ ꢀ ꢀO type) revealed a similarity in the graph-set descriptors, suggesting a

ﬁne interplay of substituent- and shape-dependent effects on strong–weak

interactions. It seems that the formation of chains or dimers is governed not only

by the presence of a tertiary Cꢀ atom, but also by the nature and crowding of the

ortho substituents of the ꢀ-aryl group.

Keywords: ꢀ-hydroxy-ꢀ-arylphosphonates;

crystal structure; hydrogen bonding; Pudovik

reaction.

Supporting information: this article has

supporting information at journals.iucr.org/c

1. Introduction

ꢀ-Hydroxyphosphonates represent a prominent class within

organophosphorus compounds due to their real or potential

biological activity. Based on their enzyme inhibitory proper-

ties (Patel et al., 1995), hydroxyphosphonates may have anti-

biotic (Kategaonkar et al., 2010; Pokalwar et al., 2006),

antifungicidal (Kategaonkar et al., 2010), antioxidant (Rao et

al., 2011; Naidu et al., 2012), anticancer (Kalla et al., 2015),

anti-HIVand anti-inﬂammatory effects (Frechette et al., 1997).

Trichlorfon [or O,O-dimethyl (2,2,2-trichloro-1-hydroxy-

ethyl)phosphonate] was an early insecticide that was the

precursor of dichlorvos (2,2-dichlorovinyl dimethylphosphate)

with an acetylcholine esterase paralyzing effect (Lorenz et al.,

1995).

A number of base- and acid-catalyzed, as well as different

solid-salt-catalyzed methods were elaborated for the synthesis

´

of ꢀ-hydroxyphosphonates (Radai

& Keglevich, 2018;

Pudovik & Konovalova, 1979; Kharasch et al., 1960; Ruveda &

De Licastro, 1972; Timmler & Kurz, 1971; Texierboullet &

Foucard, 1980, 1982a,b; Hudson et al., 2008; Sardarian &

Kaboudin, 1997; Smahi et al., 2008; Solhy et al., 2010; Kaboudin

& Nazari, 2002). Thiourea-based organo-catalysts have also

been used for the synthesis of tertiary ꢀ-hydroxyphosphonates

# 2019 International Union of Crystallography

Acta Cryst. (2019). C75, 283–293

https://doi.org/10.1107/S2053229619001839 283

research papers

Table 1

Experimental details for the preparation and characterization of ꢀ-hydroxyphosphonates 1 and 3.

³¹P NMR

Product

Time (min)

Yield (%)

ꢁP

ꢁP (reference)

M.p. (^ꢂC)

M.p. (reference) (^ꢂC)

[M + H]⁺

Entry

1a

1b

3a

3b

3c

10

120

30

330

95

86

91

88

94

23.8

24.1

21.1

22.3

22.4

24.3^a

23.8^b

21.1^c

22.3^c

22.4^d

100–101

125–126

124–125

103–104

110–111

101–102^e,f

217.1

277.1

414.1114

403.0881

383.1392

1

124^b

2^#

3

-

4

5

87–88^d

´

Notes: (#) In this case, 0.3 equivalents of triethylamine was used. References: (a) Rowe & Spilling (2001); (b) Hudson et al. (2008); (c) Radai et al. (2018); (d) Pawar et al. (2006); (e)

Keglevich et al. (2011); (f) Abramov (1952).

(Kong et al., 2012). Keglevich and co-workers reported a

microwave-assisted, solvent-free preparation of hydroxy-

phosphonates (Keglevich et al., 2011). Although a number of

green variations were developed for the synthesis of the

phosphonates under discussion, in these approaches the

reaction conditions were green only with respect to the cata-

lyst and the lack of solvents. The work-up involved the

extensive use of solvents as extractants, eluants in chromato-

graphy and as media for recrystallizations (Kumar et al., 2012;

Nandre et al., 2012; Kong et al., 2014; Kulkarni et al., 2013;

Ramananarivo et al., 2013; Santhisudha et al., 2015; Liu et al.,

2014). Keglevich and co-workers could, however, elaborate a

green method, when the hydroxyphosphonate simply crystal-

lized out in a pure form from the reaction mixture. In this case,

only a minimal amount of acetone and pentane was necessary

as the solvent (Keglevich et al., 2017). A convenient functio-

nalization of ꢀ-hydroxyphosphonates was also reported

recently (Cytlak et al., 2018) en route to the synthesis of ꢀ-

aminophosphonates. Several such novel ꢀ-aminophosphonate

crystal structures were also reported (Cytlak et al., 2018). The

structure determination of phosphonates was soon under-

taken as their economic value grew. The crystal structure of

Several related tertiary Cꢀ ꢀ-hydroxyphosphonate ester

crystal structures have been reported recently, viz. diphenyl

(hydroxyphenylmethyl)phosphonate (Fang et al., 2006c),

diethyl [hydroxy(phenyl)methyl]phosphonate (An et al., 2008;

Fang et al., 2010; Ouksel et al., 2017), dimethyl [hy-

droxy(phenyl)methyl]phosphonate (Fang et al., 2006b) and

diisopropyl (hydroxyphenylmethyl)phosphonate (Fang et al.,

2006a). Of interest are the three known independent room-

temperature structure determinations of diethyl [hy-

droxy(phenyl)methyl]phosphonate derivative. One determi-

nation reports disorder of the ethyl ester groups (An et al.,

2008), but the three have different volumes of 1296.5, 1263.5

3

˚

and 1315.2 A [Cambridge Structural Database (CSD; Groom

et al., 2016) refcodes KODYOS (An et al., 2008), KODYOS01

(Fang et al., 2010) and KODYOS02 (Ouksel et al., 2017)].

Some closely related Cꢀ methyl-group-containing crystal

structures are dimethyl (S)-[cyano(hydroxy)phenylmeth-

yl]phosphonate (Kong et al., 2012), diphenyl (1-hydroxy-1-

phenylethyl)phosphonate (Lane et al., 1996), dimethyl

(1-hydroxy-1,2-diphenylethyl)phosphonate (Acar et al., 2009),

dimethyl (1-hydroxy-1,2-diphenylethyl)phosphonate (Tahir et

al., 2009a,b) and diethyl (1-hydroxy-1-phenylethyl)phos-

phonate (Tahir et al., 2009c).

¨

trichlorfon was reported 50 years ago (Hohne & Lohs, 1969).

Figure 1

The synthesis of ꢀ-hydroxyphosphonates 1, 2 and 3.

ꢁ

´

284 Radai et al. Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates

Acta Cryst. (2019). C75, 283–293

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Table 2

Experimental details for the preparation and characterization of ꢀ-hydroxyphosphonates 2a and 2b.

³¹P NMR

Product

Time (min)

Yield (%)

ꢁP

ꢁP (reference)

M.p. (^ꢂC)

M.p. (reference) (^ꢂC)

[M + H]⁺

Entry

2a

2b

7

2

48

82

26.2

24.8

26.0^a

24.8^b

130–131

167–168

130^c

231.1

276.1

1

170–171^b

2^#

Notes: (#) ¹³C NMR (CDCl₃): ꢁ 25.8 (d, ²J = 3.3 Hz, CH₃), 53.8 (d, ²J = 8.0 Hz, OCH₃), 54.7 (d, ²J = 7.3 Hz, OCH₃), 73.7 (d, ¹J = 160.1 Hz, PCH), 123.1 (d, ⁴J = 2.7 Hz, C3), 126.8 (d, ³J =

4.2 Hz, C2), 147.2 (d, ⁵J = 3.3 Hz, C4), 148.6 (C1). References: (a) Seven et al. (2011); (b) Keglevich et al. (2017); (c) Hudson et al. (2008).

Table 3

droxy(phenyl)methyl]phosphonates, 3.

A

mixture of

Crystallization summary of compounds 1, 2 and 3 at 26 ^ꢂC.

11.0 mmol of aromatic aldehyde (benzaldehyde: 1.2 g;

2-nitrobenzaldehyde: 1.7 g; 3-chlorobenzaldehyde: 1.5 g;

4-methylbenzaldehyde: 1.3 g; 3,4-dimethoxybenzaldehyde:

1.8 g), 11.0 mmol of phosphite (dimethyl phosphite: 1.1 ml;

dibenzyl phosphite: 2.4 ml) and triethylamine (1.1 mmol,

0.15 ml) was stirred in acetone (1 ml) under reﬂux for 10–

330 min (for details, see Table 1). After adding pentane (6 ml)

to the reaction mixture, the product crystallized on cooling.

Filtration of the crystals afforded products 1a, 1b, 3b and 3c as

white crystals, and 3a as orange crystals in yields of 86–95% in

a pure form.

Compound

Solvent

Precipitant

Crystallization time

1a^a

1b^b

2a^b

2b^b

3a^b

3b^b

3c^b

methanol

acetone

pentane

5 min

48 h

24 h

72 h

–

acetone

diethyl ether

Notes: (a) crystals were obtained from the reaction mixture; (b) crystals were obtained by

recrystallization.

2.1.2. General procedure for the preparation of dimethyl

(1-hydroxy-1-phenylethyl)phosphonates, 2. A mixture of

11.0 mmol of aromatic ketone (acetophenone: 1.2 g; 4-nitro-

acetophenone: 1.7 g), dimethyl phosphite (11.0 mmol, 1.1 ml)

and triethylamine (11.0 mmol, 1.5 ml) was stirred at 26 ^ꢂC for

2–7 h. The product appeared as a white precipitate. The

reaction mixture was cooled to 5 ^ꢂC. After crystallization was

complete, the product was isolated by simple ﬁltration. The

white crystals were washed with hexane (2 ꢃ 5 ml), affording

hydroxyphosphonates 2a and 2b in yields of 48/82% in a purity

of >98% (Table 2).

Crystals were obtained by slow evaporation of various

solvents (see Table 3).

The differing crystallization times may suggest different

factors that control the process, as the almost instant crystal-

lization of 1a may suggest kinetic control of the crystal growth,

while others may well be governed by thermodynamic control.

Here we aim at describing some fundamental association

patterns in the solid state which may govern the formation of

macroscopic ordered solid objects, i.e. crystals. Structures in

general and the crystal structure in particular may be impor-

tant not only in structure–activity relationships, but also in

many simple practical properties of pharmaceuticals, such as

preparing solid dosage forms (tablettability), bio-availability

(solubility and polymorphy), storage and metabolic pathway

identiﬁcation, and many others (Ye et al., 2014). Crystal

structure descriptions of phosphonates usually allude to a

description of the association patterns observed in the solid

phase via characterization of hydrogen-bond bridges and/or

other putative favourable interactions contributing towards

the build-up of the macroscopic crystal. This and similar issues

are relevant and are the subject of recent discussions

(Edwards et al., 2017; Mackenzie et al., 2017). Another series

of studies has dealt with the two different ways of looking at

intermolecular interactions either with an emphasis on speciﬁc

atom–atom contacts (whether interactions or bonds) or rather

as a whole-of-molecule approach that is sort of blind to atom–

atom interactions (Dunitz, 2015; Lecomte et al., 2015; Thakur

et al., 2015).

2.2. Data collection, structure solution and refinement

The crystal structure of compound 1a has been reported at

room temperature (Fang et al., 2006b) and thus a redetermi-

nation at low temperature was carried out. Hydroxy H atoms

were located in difference Fourier maps and reﬁned keeping

the isotropic displacements adjusted to 20% greater than that

of the O-atom U_isovalue. All C—H hydrogens were placed at

idealized positions and treated as riding atoms, with isotropic

parameters 20 or 50% (for methyl C atoms) greater than for

the C atoms to which they are attached. The crystal of 3b is the

only in this series which crystallized in a chiral space group. As

no enantioselective agents were applied, this means that con-

glomerate crystallization (spontaneous resolution) occurred

on crystallization. The high Flack x = 0.35 (12) and its high s.u.

value indicate that the measured single crystal was a racemic

twin in approximate 0.33:0.67 proportions. Further crystal-

lographic experimental details (such as space groups, cells and

2. Experimental

2.1. Syntheses and crystallizations

1

The ³¹P, ¹³C and H NMR spectra were taken on a Bruker

Avance-300 instrument operating at 121.5, 75.5 and 300 MHz,

respectively. The exact mass measurements were performed

using a Q-TOF Premier mass spectrometer in positive elec-

trospray mode. The melting points were determined by

differential scanning calorimetry (DSC) measurements using a

Setaram DSC 92 instrument.

2.1.1. General procedure for the preparation of dimethyl

[hydroxy(phenyl)methyl]phosphonates, 1, and dibenzyl [hy-

ꢁ

´

Acta Cryst. (2019). C75, 283–293

Radai et al.

Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates 285

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Table 4

Experimental details.

For all determinations, H atoms were treated by a mixture of independent and constrained reﬁnement.

1a

1b

2a

2b

Crystal data

Chemical formula

M_r

C₉H₁₃O₄P

216.16

C₁₁H₁₇O₆P

276.21

C₁₀H₁₅O₄P

230.19

C₁₀H₁₄NO₆P

275.19

Crystal system, space group

Temperature (K)

Monoclinic, P2₁/n

173

8.4039 (5), 7.7007 (3),

16.6012 (7)

90, 99.149 (4), 90

Monoclinic, C2/c

173

39.464 (3), 8.5132 (4),

8.0044 (3)

90, 100.620 (5), 90

Monoclinic, P2₁/c

173

8.4780 (3), 17.2370 (6),

8.1357 (3)

90, 106.484 (4), 90

Triclinic, P1

173

˚

a, b, c (A)

8.1800 (4), 8.4006 (6),

9.9661 (4)

102.173 (5), 94.897 (4),

107.504 (5)

630.26 (6)

2

Mo Kꢀ

0.24

0.40 ꢃ 0.35 ꢃ 0.20

ꢀ, ꢂ, ꢃ (^ꢂ)

3

˚

V (A )

1060.69 (9)

4

Mo Kꢀ

0.25

2643.2 (2)

8

Mo Kꢀ

0.23

1140.05 (7)

4

Mo Kꢀ

0.23

Z

Radiation type

ꢄ (mm^ꢄ1

Crystal size (mm)

)

0.40 ꢃ 0.20 ꢃ 0.04

0.30 ꢃ 0.20 ꢃ 0.05

0.40 ꢃ 0.35 ꢃ 0.25

Data collection

Diffractometer

Absorption correction

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

T_min, T_max

0.846, 1.000

20344, 3209, 2491

0.956, 1.000

13696, 4023, 2812

0.933, 1.000

22954, 3450, 3080

0.948, 1.000

12564, 3827, 3070

No. of measured, indepen-

dent and observed

[I > 2ꢅ(I)] reﬂections

R_int

0.041

0.714

0.049

0.714

0.025

0.714

0.028

0.714

ꢄ1

˚

(sin ꢆ/ꢇ)_max(A

)

Reﬁnement

R[F²> 2ꢅ(F²)], wR(F²), S

No. of reﬂections

0.038, 0.108, 1.02

3209

0.047, 0.126, 1.03

4023

0.031, 0.089, 1.04

3450

0.041, 0.114, 1.03

3827

No. of parameters

No. of restraints

Áꢈ_max, Áꢈ_min(e A

139

0

0.33, ꢄ0.27

178

0

0.40, ꢄ0.29

150

0

0.35, ꢄ0.19

176

0

0.34, ꢄ0.28

ꢄ3

˚

)

3a

3b

3c

Crystal data

Chemical formula

M_r

C₂₁H₂₀NO₆P

413.35

C₂₁H₂₀ClO₄P

402.79

C₂₂H₂₃O₄P

382.37

Crystal system, space group

Temperature (K)

Triclinic, P1

133

10.0795 (3), 13.8530 (6),

15.9354 (5)

111.110 (4), 90.852 (3), 106.326 (3)

1975.23 (13)

4

Mo Kꢀ

0.18

Monoclinic, P2₁

133

10.4239 (8), 7.8757 (5), 12.0461 (7)

Orthorhombic, Pbca

173

16.7332 (8), 8.2012 (3),

28.0902 (13)

90, 90, 90

3854.9 (3)

8

Mo Kꢀ

0.17

˚

a, b, c (A)

ꢀ, ꢂ, ꢃ (^ꢂ)

90, 103.775 (7), 90

960.49 (11)

2

Mo Kꢀ

0.31

0.30 ꢃ 0.22 ꢃ 0.20

3

˚

V (A )

Z

Radiation type

ꢄ (mm^ꢄ1

Crystal size (mm)

)

0.43 ꢃ 0.30 ꢃ 0.25

0.37 ꢃ 0.15 ꢃ 0.05

Data collection

Diffractometer

Absorption correction

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

Agilent Xcalibur Sapphire3

Multi-scan (CrysAlis PRO;

Agilent, 2014)

T_min, T_max

0.980, 1.000

39828, 11989, 8512

0.991, 1.000

6934, 3407, 2955

0.980, 1.000

29616, 4758, 3133

No. of measured, independent and

observed [I > 2ꢅ(I)] reﬂections

R_int

0.038

0.714

0.028

0.625

0.070

0.667

ꢄ1

˚

(sin ꢆ/ꢇ)_max(A

)

Reﬁnement

R[F²> 2ꢅ(F²)], wR(F²), S

No. of reﬂections

0.046, 0.124, 1.03

11989

0.047, 0.114, 1.05

3407

0.056, 0.150, 1.02

4758

No. of parameters

No. of restraints

Áꢈ_max, Áꢈ_min(e A

Absolute structure

Absolute structure parameter

565

0

255

1

265

0

ꢄ3

˚

)

0.60, ꢄ0.31

0.34, ꢄ0.20

0.45, ꢄ0.26

–

Reﬁned as an inversion twin

0.35 (12)

–

Computer programs: CrysAlis PRO (Agilent, 2014), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b), ORTEP (Burnett & Johnson, 1996), ORTEP-3 (Farrugia, 2012),

DIAMOND (Brandenburg, 1999) and PLATON (Spek, 2009).

ꢁ

´

286 Radai et al. Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates

Acta Cryst. (2019). C75, 283–293

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Figure 3

Figure 2

The molecular structure of 1a, showing the atomic numbering and 50%

probability displacement parameters for the non-H atoms.

The molecular structure of 1b (the asymmetric unit), showing the atomic

numbering and 50% probability displacement parameters for the non-H

atoms.

containing phosphonates has been reported previously [e.g. in

¨

data collection), as well as computational results (model

reﬁnement and ﬁnal notes), are summarized in Table 4.

trichlophone (Hohne & Lohs, 1969) or in Ouksel et al. (2017)].

A packing drawing for compound 1b (Fig. SF1 in the

supporting information) shows a typical arrangement for this

class of contacts.

The quaternary Cꢀ methyl-containing derivatives which

form dimers are 2a and 2b, while tertiary Cꢀ—H equipped

hydroxyphosphonate 3a forms a dimer even in its asymmetric

unit. The other tertiary ꢀ-H-containing counterparts, i.e. 3b

and 3c, form chains.

2.3. Other computing tools

The Cambridge Structural Database (CSD; Groom et al.,

2016) programs ConQuest (Versions 1.22 and 1.23; Bruno et

al., 2002) and Mercury (Macrae et al., 2008) were used with

their built-in tools (such as plotting, graph-set analysis and

statistical tools). Incidentally, the legacy CSD program

RPLUTO was also applied. For an overview of some of the

electronic aspects of the interactions in these crystals, Crys-

talExplorer was applied (Turner et al., 2017). Underlying

energy calculations were performed both at the CE-HF

(Hartree–Fock) and CE B3LYP/6-31G(d,p) levels. Energy

frameworks resulting from these two approaches proved to be

nearly identical with respect to both the energy components

magnitude and the directional features in the respective

crystals. Thus, the resulting minor discrepancies either in the

components (Coulombic, dispersion and repulsion forces) or

in the total energies only showed hardly visible differences.

However, most of these results will be reported in a later

publication and only one particular aspect for 3a is covered

here.

´

Compound 1a is possibly isostructural (Kalman et al., 1993)

with the known diethyl [hydroxy(phenyl)methyl]phosphonate

crystal structures (An et al., 2008; Fang et al., 2010; Ouksel et

al., 2017; see Table ST1 in the supporting information).

Packing drawings for 2a and 3a (see Figs. SF2 and SF3 in the

supporting information) show the basic primary propagation

forms of the O—Hꢀ ꢀ ꢀO hydrogen-bond bridges in the crystal

packing for the centrosymmetric dimer and for the pseudo-

centrosymmetric types.

3. Results and discussion

The structural diagrams of the seven crystal structures deter-

mined in this study are shown in Fig. 1, and the crystal-

lographic asymmetric-unit contents are shown in Figs. 2–8.

These seven crystal structures are classiﬁed and shown in

the order of their principal hydrogen-bond motifs based on

the topology of the O—Hꢀ ꢀ ꢀO P hydrogen bonds. This

group simply follows the literature usage in naming ‘chains’

and ‘dimers’ as the principal propagation forms of O—Hꢀ ꢀ ꢀO

hydrogen-bond bridges in the crystal packing of the individual

solid forms (e.g. Etter, 1990; Bernstein et al., 1995; Tahir et al.,

2009a; Ouksel et al., 2017).

Figure 4

The tertiary Cꢀ H-atom-containing and chain-forming

compounds 1a, 1b, 3b and 3c are discussed ﬁrst. The formation

of chain-like hydrogen-bond bridges in tertiary Cꢀ—H-

The molecular structure of 3b (the asymmetric unit), showing the atomic

numbering and 50% probability displacement parameters for the non-H

atoms.

ꢁ

´

Acta Cryst. (2019). C75, 283–293

Radai et al.

Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates 287

research papers

Table 5

OPCO torsion angles (^ꢂ) in 1a–3c.

Compound 3a has two independent molecules in the asymmetric unit, hence

the two values.

Compound

OPCO

Torsion (^ꢂ)

1a

1b

2a

2b

3a

3b

3c

O1—P1—C1—O4

O1—P1—C5—O4

O1—P1—C1—O4

O7—P2—C22—O10

O1—P1—C1—O4

66.4 (1)

54.6 (1)

ꢄ56.5 (1)

64.3 (1)

ꢄ74.0 (1)

73.5 (1)

55.5 (3)

55.4 (2)

This work was primarily initiated in order to explain the

packing formation of these seven related ꢀ-hydroxy-ꢀ-aryl-

phosphonate target compounds. The main driving force was

supposed to be the O—Hꢀ ꢀ ꢀO P-type hydrogen-bond bridge

formation. About three-quarters (30 out of 40, see supporting

information) of such structures adopt some form of chain. We

believe that this is related partly to the crowding around the

Cꢀ atom and partly due to electronic reasons. The usual chain

formation in our seven-membered mini-series is broken for

the two quaternary Cꢀ-atom structures (i.e. 2a and 2b) and,

somewhat surprisingly, for a tertiary Cꢀ-atom derivative (3a)

also, which is a possible irregularity.

Figure 6

The molecular structure of 2a (the asymmetric unit), showing the atomic

numbering and 50% probability displacement parameters for the non-H

atoms.

notation is used hereinafter in the conventional sense in

conformity with database notations). The O P—C—OH

torsion angles (OPCO hereinafter) are listed for the studied

crystal structures 1a–3c in Table 5.

The absolute values of these eight angular angles are

distributed around a mean value of 62.5^ꢂ. Thus, one is inclined

to believe that this torsion is swaying around 60^ꢂin the

synclinal (sc) conformation range. The four molecules in the

dimer-type crystal structures have a mean value of 58^ꢂ, while

the rest show a mean value of 67.1^ꢂ. The torsion angles are

rather soft parameters, hence the individual deviations from

either the mean or from any other in this small sample may not

have particular signiﬁcance. Similar values and like deviations

arise from literature data obtained from the Cambridge

Structural Database (CSD; Groom et al., 2016). Saying there is

no particular signiﬁcance just indicates that deviations and the

small torsion-angle variations might well be signs of inter-

molecular effects that may span a range from a few tenths to a

few kJ mol^ꢄ1energies or so (Sarkar & Row, 2017). A search

for the chemical fragment (Fig. SF4 in the supporting infor-

mation) with an acyclic hydroxyphosphonate ester unit and a

3.1. Analysis of some intra- and intermolecular features

As the synthesis and a crystal structure description of

compound 1a have been published previously (Fang et al.,

2006b), only other aspects will be reported here. Low-

temperature geometry data of 1a are consistent with the other

structures presented in this article. Intramolecular bonding

features will not be discussed at length as the bonding para-

meters conform to expected mean values within the usual

signiﬁcance criteria.

The only intramolecular shape descriptor we deal with is the

torsion angle along the P—Cꢀ bond, as deﬁned by the hydroxy

O atom and the O atom of the P O unit (double-bond

Figure 5

Figure 7

The molecular structure of 3c (the asymmetric unit), showing the atomic

numbering and 50% probability displacement parameters for the non-H

atoms.

The molecular structure of 2b (the asymmetric unit), showing the atomic

numbering and 50% probability displacement parameters for the non-H

atoms.

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288 Radai et al. Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates

Acta Cryst. (2019). C75, 283–293

research papers

Figure 8

The molecular structure of 3a (the asymmetric unit), showing the atomic numbering and 50% probability displacement parameters for the non-H atoms.

The dimer formed by hydrogen-bond bridges is shown with broken lines. This pseudocentrosymmetric dimer is quite similar to the true centrosymmetric

dimers formed in 2a and 2b.

Table 6

Statistic descriptors of the 36 OPCO values around the sc conformation range in the CSD.

Extracted from a full table and rounded appropriately to integer numbers. The most relevant numbers are printed in bold.

Count

36

Min (^ꢂ)

Max (^ꢂ)

Mean (^ꢂ)

Sample std dev. (^ꢂ)

Mean std dev. (^ꢂ)

Skewness

0.56

Kurtosis

Median (^ꢂ)

OPCO

48

83

64

9

7

ꢄ0.49

61

C—O—H moiety within hydrogen-bond bridging distance to

the P O group. This search resulted in 36 hits (i.e. crystal

structures) which contain 42 independent molecular frag-

ments. Of these 42, the OPCO angle values of 36 fall in the

synperiplanar/synclinal ranges (i.e. between ꢄ30 and 30^ꢂ, and

between 30 and 90^ꢂfor sp and sc, respectively). Thus, when the

OPCO angle values are truncated to this range, the distribu-

tion values come close to those seen in the structures here

(Table 6). The OPCO torsion angle seems to favour this low

synclinal conformation range just at the border of the sp

region. Of historical interest is that trichlorfon has the lowest

reported OPCO torsion angle (28^ꢂ).

Of further interest is that when the full search results are

examined it becomes apparent (Fig. 9) that some OPCO

torsions adopt values close to 180^ꢂ(6 in the sample of total of

42) attaining the antiperiplanar conformation. This corre-

sponds to the traditional trans disposition of the two O atoms

across the P—C bond. None of our compounds adopts this

conformation. The question is whether such conformational

changes have any inﬂuence regarding the hydrogen-bond

bridge-forming ability?

Thus, the intermolecular relationships need to be examined.

A quick overview is provided by the polar scattergram of the

OPCO values against the hydrogen-bond bridge angles

(Fig. 10), as well as a summary of the statistics of some of the

hydrogen-bond bridge distance parameters (Table 7). These

both point towards nondiscriminative hydrogen-bond bridge

features conforming well to expected standards, thus indi-

cating normal and possibly well-deﬁned hydrogen-bond

bridges. Apparently, the OPCO torsion-angle values do not

indicate any particular inﬂuence on the hydrogen-bond bridge

geometry.

Figure 9

A polar histogram of the HO—C—P O torsion-angle distribution in

acyclic P(OR) esters (i.e. omitting cyclic constrained esters). There are

still several high antiperiplanar (ap, trans) conformations (6 out of 42

hits).

A further aspect of the intermolecular interactions is,

however, their topology. As this type was recognized in the

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Radai et al.

Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates 289

research papers

Table 8

Hydrogen-bond graph-set descriptors in compounds 1a–3c.

Table 7

Statistics table of the intermolecular hydrogen-bond bridges of acyclic

esters of hydroxyphosphonate fragments in the CSD.

Primary contacts are O—Hꢀ ꢀ ꢀO hydrogen-bond bridges, while secondary

contacts encompass additional C—Hꢀ ꢀ ꢀO hydrogen-bond bridges involving

those used in the primary contact as well (for a graphical overview, see Table

ST2 in the supporting information.

35 crystal structures yielded 42 independent fragments containing the search

moiety (the table is restricted to the most known parameters only). AHD is

the P Oꢀ ꢀ ꢀH—O hydrogen-bond bridge angle and d is the Oꢀ ꢀ ꢀH distance.

The angular values are rounded to whole degrees.

Compound

Primary GS

Secondary GS

Sample

Count Min. Max. Mean std dev. Mean dev. Median

1a

1b

2a

2b

3a

3b

3c

C(5)

R²₂(10)

C(5)

R²₂(8)

Name

R²₂(8)

R²₂(10)

AHD (^ꢂ) 42

˚

136 178

2.59 2.77

166

2.70

11

0.04

9

0.03

170

2.70

d (A)

42

R²₂(10), with S(6) and S(5)

R²₂(8)

C(5)

C(8), C₂²(13), with S(7)

form of chain-like or dimer involvement of the P Oꢀ ꢀ ꢀH—O

hydrogen-bond bridges, the quest is to try to identify condi-

tions which would decide in favour of either option. Initially,

the presence of the ꢀ-H atom at the chiral C atom (ternary C

atom in compounds 1 and 3) was supposed to be responsible

for chain formation. In contrast, the presence of the ꢀ-methyl

substituent (i.e. a quaternary C atom) would promote dimer

formation, as seen in compounds 2. Nevertheless, the crystal

structure of 3a, which is a dimer-forming tertiary Cꢀ H-atom

species, seems to be an exception in this assumption.

total energy (shown as a thick blue rod) aligns very well with

the direction of the Oꢀ ꢀ ꢀH—O hydrogen-bond bridges, thus

explaining the dominant vectorial interaction in this crystal.

As the dominating electrostatic contribution comes from the

O—Hꢀ ꢀ ꢀO P-type hydrogen-bond bridges, the simplest

approach lists these interactions ﬁrst (Table 8). Five-

membered chains of one donor/acceptor each (chains) or rings

twice as large of two donors/acceptors each (dimers) consti-

tute the basic motif propagation.

3.2. Graph-set characterization

The dominant O—Hꢀ ꢀ ꢀO hydrogen-bond bridges are the

primary component. When adding any C—H types to the

possible donors, this picture is complemented by the

secondary graph-set motifs such that these latter partly

overlap with the primary sets. This is to say that at least one of

the O atoms from the primary set is involved (i.e. a joint O—

Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀO motif exists). This also makes sense, as

the many C—Hꢀ ꢀ ꢀO interactions might be a substantial factor

due to their large number alone.

Examining the primary dimer sets (i.e. 2a, 2b and 3a),

especially with regard to seeking an explanation why a dimer

(even more in the asymmetric unit) is formed in species 3a, we

can establish the following: in 2a, prevalent rings made up by

Graph-set descriptions have been used since the pioneering

work of Etter and Bernstein (Etter, 1990; Bernstein et al.,

1995) for a topological representation of the intra- and mainly

intermolecular hydrogen-bond contacts. Compound 3a is

exceptional in many aspects. A representation abstracted from

its crystal energy framework computation result from

CrystalExplorer (Turner et al., 2017) is shown in graphical

form (Fig. 11). This serves also to exemplify the relationship

between the P Oꢀ ꢀ ꢀH—O hydrogen-bond bridges, direc-

tionality and energy relations.

The Coulombic component provides here most of the total

energy, with the major dispersion contribution aligned also

close to parallel to the electrostatic contribution. The resulting

Figure 11

The largest total energy bar (blue rod) is shown in the 3a asymmetric unit

dimer from its lattice energy framework. This shows the largest cohesive

total energy relationship between molecular centres. One molecule is

shown with its unsigned Hirshfeld surface also, while the other is

represented in a displacement ellipsoid plot only, with the two Hꢀ ꢀ ꢀO-to-

Figure 10

A polar scattergram of the HO—C—P O torsion angles versus the

˚

P

Oꢀ ꢀ ꢀH—O hydrogen-bond bridge angle in acyclic P(OR) esters.

acceptor distances listed (with values of 1.657 and 1.658 A).

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290 Radai et al. Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates

Acta Cryst. (2019). C75, 283–293

research papers

dimers. Compound 3b has a secondary set that is identical

topologically and functionally with those in compounds 1 in a

chiral crystal lattice. Compound 3c has a more confusing

secondary set situation. It is hard to decide the ranking as

there are at least two competitive chain sets, both involving o-

C—H H atoms. In the S(7) set, an intramolecular distance

˚

(2.66 A) links one of the benzyl o-H atoms to the O P group.

In the other C(8) set, an o-H atom of the other benzyl ester

˚

group approaches (2.57 A) an O—H group of the next 3c

molecule. Both of these are relatively longer distances with

respect to the sum of the van der Waals radii concerned.

Moreover, a C₂²(13) graph set links two more molecules to the

base graph set via contacts both to a screw and to a glide-

related molecule from the basal ꢀ-H atom to a screw-related

Figure 12

Aview of the decisive internal hydrogen-bond bridges in the asymmetric-

˚

unit dimer of 3a. Distances are in A and their values stem from a

normalized H-atom position geometry. As to their uncertainties, one can

˚

estimate that they are in the order of 0.01 A.

˚

P group (3.17 A), which is also acting towards a glide-

O

related o-H atom (2.57 A) of that benzyl moiety.

˚

4. Conclusions

the dominant O—Hꢀ ꢀ ꢀO interactions are complemented by an

R²₂(10) secondary motif involving two symmetry-related ortho

H—C groups from the phenyl group. This points to the

important role that the phenyl ortho substituents may play.

The other quaternary Cꢀ compound, 2b, has an identical

ranking of rings in the secondary complement. But these are

not from o-C—H but from two symmetry-related ꢀ-methyl H

atoms. The 3a primary set is the same ten-membered ring, but

formed through intermolecular hydrogen-bond bridges

between the two molecules of the asymmetric unit (Z⁰= 2),

while the secondary set forms between symmetry-centre-

related molecules. Thus, they are symmetrically identical with

those in 2a and 2b, but they involve intermolecular C—Hꢀ ꢀ ꢀO

hydrogen-bond contacts in the case of 3a. Extending the

hydrogen-bond bridge functions for intramolecular C—Hꢀ ꢀ ꢀO

results in the S(6) and S(5) patterns. This self-binding involves

the o-NO₂-group O atoms to the Cꢀ H atom [S(6) pattern] and

to the neighbouring m-C—H group [S(5) form] in both 3a

molecules (Fig. 12).

Practically identical dimensions and patterns underline the

important electronic and steric functions of the o-NO₂groups

towards their neighbouring units in both 3a molecules. In the

case of dimethyl [hydroxy(2-nitrophenyl)methyl]phosphon-

ate, dimer formation with an identical R²₂(10) primary

hydrogen-bonded ring was reported (Tahir et al., 2009a),

together with similar internal o-NO₂-group involvement. The

o-NO₂group forms the same S(6) and S(5) rings to the Cꢀ H

atom and to the next m-C—H group, respectively. Thus, 3a, in

spite of having a tertiary Cꢀ atom, it does not form a chain-like

packing motif but a dimer, similar to 2a and 2b with their

quaternary Cꢀ atom. In such a way, the o-NO₂groups act

[torsion angles O5—N1—C3—C2 = ꢄ9.2 (2)^ꢂand O11—N2—

C24—C23 = 13.7 (2)^ꢂ] not only as effective steric shielding for

the H atom at Cꢀ (Fig. SF5 in the supporting information), but

also as if they were quaternary C-atom substituents. Thus, we

hypothesize, that compounds with tertiary Cꢀ atoms are prone

to form chains, while those with quaternary Cꢀ atoms, or with

a sterically electronically shielded Cꢀ H atom, tend to cause

There seem to be just too many variables and conditions, not

to mention the actual crystallization conditions, that may

affect the ﬁnal outcome of crystal formation, i.e. the topology

of the associates formed under particular circumstances. We

think that the initial assumption concerning the crowding

around the Cꢀ atom is an important piece of the puzzle. The

simplest realization of crowding is the introduction of a methyl

group at Cꢀ, i.e. for 2a and 2b. Electronic modiﬁcation through

either substituents or through noncovalent interactions may

also affect a tertiary C—H group. An important role of the

C—Hꢀ ꢀ ꢀO interactions is seen in 3a. In spite of having a

tertiary Cꢀ atom, it does not form a chain-like packing motif

but a dimer, like 2a and 2b with their quaternary Cꢀ atom.

Thus, we postulate the hypothesis that compounds with

tertiary Cꢀ atoms are prone to form chains, while those with

quaternary Cꢀ atoms, or with a sterically electronically

shielded Cꢀ H atom, tend to promote the formation of dimers.

Nevertheless, we believe, even on the basis of this limited

study, that we may call attention to several factors that have an

inﬂuence on the hydrogen-bonding motif outcome. As

mentioned here several times, grouping the compounds on the

tertiary–quaternary feature of the Cꢀ atom is one of these

factors. The role and nature of the substituents, especially in

the ortho positions of the aromatic phenyl-type moieties, that

are immediately linked to Cꢀ modify such a classiﬁcation via

intramolecular effects. It seems from the graph-set analysis

that the dominating (primary) hydrogen-bond bridges are not

only co-existent with the weaker but more numerous

secondary bridges, but that these may provide a complemen-

tary vehicle towards making crystals. One may also observe a

degree of similarity in the primary and secondary graph sets of

the studied molecular crystals, thus reﬂecting molecular

similarity at another more abstract level.

Acknowledgements

ZR is grateful for the fellowship provided by Chinoin–Sanoﬁ

´

Pharmaceuticals and the Jozsef Varga Foundation. A small

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ꢁ

´

Acta Cryst. (2019). C75, 283–293

Radai et al.

Typical crystal structures of ꢀ-hydroxy-ꢀ-arylphosphonates 293

supporting information

Acta Cryst. (2019). C75, 283-293 [https://doi.org/10.1107/S2053229619001839]

The typical crystal structures of a few representative α-aryl-α-hydroxyphospho-

nates

Zita Rádai, Nóra Zsuzsa Kiss, Mátyás Czugler, Konstantin Karaghiosoff and György Keglevich

Computing details

For all structures, data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data

reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s)

used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP (Burnett & Johnson, 1996),

ORTEP-3 (Farrugia, 2012), PLATON (Spek, 2009) and DIAMOND (Brandenburg, 1999); software used to prepare

material for publication: PLATON (Spek, 2009).

Dibenzyl [hydroxy(4-methylphenyl)methyl]phosphonate (3c)

Crystal data

C₂₂H₂₃O₄P

M_r= 382.37

D_x= 1.318 Mg m⁻³

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 4004 reflections

θ = 4.5–27.9°

Orthorhombic, Pbca

a = 16.7332 (8) Å

b = 8.2012 (3) Å

c = 28.0902 (13) Å

V = 3854.9 (3) Å³

Z = 8

µ = 0.17 mm⁻¹

T = 173 K

Block, colorless

0.37 × 0.15 × 0.05 mm

F(000) = 1616

Data collection

Agilent Xcalibur Sapphire3

diffractometer

Radiation source: Enhance (Mo) X-ray Source

Detector resolution: 15.9809 pixels mm^-1

ω scans

29616 measured reflections

4758 independent reflections

3133 reflections with I > 2σ(I)

R_int= 0.070

θ

_max= 28.3°, θ_min= 4.4°

Absorption correction: multi-scan

(CrysAlis PRO; Agilent, 2014)

h = −22→21

k = −10→10

l = −36→37

T

_min= 0.980, T_max= 1.000

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.056

wR(F²) = 0.150

S = 1.02

Hydrogen site location: mixed

H atoms treated by a mixture of independent

and constrained refinement

w = 1/[σ²(F_o²) + (0.0669P)²+ 1.3244P]

where P = (F_o²+ 2F_c²)/3

4758 reflections

265 parameters

0 restraints

(Δ/σ)_max= 0.001

Δρ_max= 0.45 e Å⁻³

Δρ_min= −0.26 e Å⁻³

Acta Cryst. (2019). C75, 283-293

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supporting information

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 F²against 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> 2σ(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 F²are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

An Xcalibur, Sapphire3 detector equipped diffractometer was used with an Enhance Mo Kα X-ray radiation to collect all

the intensity data. The program CrysAlis PRO (CrysAlisPro, Agilent, 2014) was used for data collection, space group

determination and all data reduction purposes including empirical absorption correction using spherical harmonics. The

initial structure models were provided by direct methods using SHELXT (Sheldrick, 2015a) and refined using full-matrix

least-squares on F²using SHELXL (Sheldrick, 2015b). All non-H atoms were refined anisotropically.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²)

x

y

z

U_iso*/U_eq

P1

O1

O2

O3

C5

O4

C10

C3

H3

0.86630 (3)

0.88249 (10)

0.83579 (9)

0.79822 (9)

1.02433 (14)

1.01055 (11)

0.71903 (14)

1.03925 (14)

1.0670 (8)

0.73182 (17)

0.7791 (15)

0.95057 (13)

0.9350

0.11650 (7)

0.28792 (18)

0.00874 (17)

0.09657 (16)

0.1749 (3)

0.0164 (2)

0.1766 (3)

0.1711 (3)

0.2088 (10)

0.1995 (3)

0.2462 (15)

−0.0002 (3)

−0.1175

0.74859 (2)

0.76026 (6)

0.79113 (5)

0.71029 (5)

0.58777 (8)

0.76139 (6)

0.64312 (9)

0.67304 (9)

0.7011 (8)

0.59491 (10)

0.5842 (4)

0.72631 (8)

0.7237

0.02500 (16)

0.0334 (4)

0.0314 (4)

0.0288 (4)

0.0340 (5)

0.0395 (4)

0.0332 (5)

0.0335 (5)

0.040*

0.0421 (6)

0.051*

0.0285 (5)

0.034*

C11

H11

C1

H1

C18

H18

C2

C7

H7

C4

H4

C17

C19

H19

C6

0.87025 (14)

0.9039 (10)

0.97640 (13)

0.93737 (14)

0.8948 (12)

1.06260 (15)

1.1080 (12)

0.79922 (14)

0.89383 (17)

0.9437 (15)

0.96076 (14)

0.9318 (8)

0.75307 (15)

0.7036 (14)

0.77049 (14)

0.7267 (8)

0.7485 (4)

0.64759 (15)

0.1879 (3)

0.2212 (10)

0.0618 (2)

0.0092 (3)

−0.065 (2)

0.2263 (3)

0.305 (2)

0.1056 (3)

0.2232 (3)

0.2807 (17)

0.0661 (3)

0.0289 (10)

0.0584 (3)

−0.0020 (17)

0.0704 (3)

−0.0121 (14)

0.1722 (18)

0.1085 (3)

0.87877 (9)

0.8520 (8)

0.0363 (5)

0.044*

0.0272 (5)

0.0303 (5)

0.036*

0.0369 (6)

0.044*

0.0308 (5)

0.0398 (6)

0.048*

0.0339 (5)

0.041*

0.0366 (6)

0.044*

0.0334 (5)

0.040*

0.67771 (8)

0.63681 (8)

0.63923 (10)

0.62880 (9)

0.62631 (11)

0.87028 (8)

0.92481 (9)

0.93039 (19)

0.59253 (8)

0.5637 (8)

0.90880 (9)

0.90344 (18)

0.82078 (8)

0.82201 (8)

0.8064 (3)

H6

C22

H22

C16

H16A

H16B

C15

0.65822 (10)

0.0381 (6)

Acta Cryst. (2019). C75, 283-293

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supporting information

H15

C21

H21

C20

H20

C13

H13

C12

H12

C14

H14

C8

H8A

H8B

H8C

C9

H9A

H9B

H40

0.6377 (3)

0.77629 (16)

0.7423 (10)

0.84685 (17)

0.8624 (6)

0.6045 (2)

0.5656 (14)

0.6739 (2)

0.6819 (4)

0.59054 (18)

0.5416 (16)

1.05096 (18)

1.0775 (11)

1.0066 (8)

0.0941 (5)

0.0958 (3)

0.0644 (10)

0.1770 (3)

0.2000 (8)

0.0829 (3)

0.0496 (12)

0.1524 (4)

0.1678 (7)

0.0609 (3)

0.0130 (16)

0.2326 (3)

0.332 (2)

0.6925 (10)

0.95484 (9)

0.9818 (8)

0.96282 (10)

0.9928 (10)

0.57840 (12)

0.5561 (8)

0.56281 (11)

0.5310 (12)

0.62603 (11)

0.6367 (4)

0.53963 (10)

0.54271 (13)

0.5200 (4)

0.046*

0.0439 (6)

0.053*

0.0439 (6)

0.053*

0.0545 (8)

0.065*

0.0543 (8)

0.065*

0.0496 (7)

0.060*

0.0510 (7)

0.076*

0.246 (2)

1.0853 (11)

0.78111 (16)

0.8320 (9)

0.7608 (4)

1.0494 (17)

0.1559 (17)

0.2317 (3)

0.2650 (7)

0.3304 (18)

−0.069 (3)

0.5263 (4)

0.67775 (9)

0.6600 (3)

0.6965 (3)

0.7537 (9)

0.076*

0.0365 (6)

0.044*

Atomic displacement parameters (Å²)

U¹¹

U²²

U³³

U¹²

U¹³

U²³

P1

O1

O2

O3

C5

O4

C10

C3

C11

C1

0.0241 (3)

0.0343 (10)

0.0307 (9)

0.0263 (8)

0.0316 (13)

0.0338 (10)

0.0333 (14)

0.0285 (13)

0.0348 (15)

0.0293 (12)

0.0315 (14)

0.0273 (12)

0.0295 (13)

0.0314 (14)

0.0264 (12)

0.0376 (15)

0.0356 (14)

0.0312 (14)

0.0274 (13)

0.0391 (15)

0.0387 (15)

0.0468 (17)

0.0544 (19)

0.069 (2)

0.0235 (3)

0.0261 (8)

0.0317 (8)

0.0274 (3)

0.0000 (2)

−0.0042 (6)

0.0046 (7)

−0.0008 (6)

0.0058 (10)

0.0099 (8)

−0.0007 (2)

−0.0002 (7)

0.0043 (7)

−0.0014 (2)

−0.0049 (6)

0.0026 (6)

0.0398 (10)

0.0318 (9)

0.0368 (9)

0.0385 (14)

0.0385 (10)

0.0417 (14)

0.0371 (13)

0.0503 (17)

0.0274 (12)

0.0379 (14)

0.0291 (12)

0.0320 (12)

0.0472 (15)

0.0359 (13)

0.0417 (15)

0.0302 (13)

0.0395 (15)

0.0355 (13)

0.0428 (15)

0.0358 (14)

0.0331 (14)

0.065 (2)

0.0233 (7)

0.0319 (12)

0.0462 (10)

0.0245 (11)

0.0348 (12)

0.0412 (14)

0.0288 (11)

0.0395 (13)

0.0253 (10)

0.0295 (11)

0.0321 (12)

0.0300 (11)

0.0400 (14)

0.0360 (12)

0.0390 (13)

0.0374 (12)

0.0325 (13)

0.0571 (17)

0.0520 (15)

0.0442 (16)

0.0599 (18)

0.0376 (14)

−0.0052 (6)

0.0097 (10)

−0.0069 (7)

−0.0096 (10)

−0.0003 (10)

0.0032 (12)

−0.0030 (9)

0.0035 (10)

0.0008 (9)

0.0032 (6)

0.0033 (10)

−0.0040 (7)

0.0001 (9)

0.0078 (9)

−0.0001 (9)

0.0066 (11)

0.0041 (9)

0.0007 (10)

0.0046 (9)

−0.0046 (9)

−0.0043 (10)

0.0063 (9)

0.0007 (11)

0.0009 (10)

0.0023 (10)

0.0003 (10)

0.0028 (10)

0.0085 (12)

0.0113 (13)

0.0061 (14)

0.0163 (16)

−0.0033 (11)

−0.0092 (10)

0.0078 (11)

−0.0032 (8)

0.0022 (10)

−0.0027 (8)

−0.0016 (9)

−0.0036 (10)

0.0002 (9)

0.0001 (11)

−0.0040 (9)

0.0030 (10)

0.0000 (10)

0.0084 (10)

0.0075 (11)

−0.0001 (11)

−0.0060 (14)

0.0032 (12)

0.0075 (13)

C18

C2

C7

0.0000 (9)

0.0073 (11)

0.0029 (9)

C4

C17

C19

C6

−0.0044 (11)

−0.0026 (10)

0.0060 (10)

0.0059 (9)

0.0006 (11)

0.0103 (11)

−0.0048 (12)

−0.0302 (16)

−0.0069 (14)

−0.0111 (14)

C22

C16

C15

C21

C20

C13

C12

C14

0.0341 (15)

0.076 (2)

0.0355 (16)

Acta Cryst. (2019). C75, 283-293

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supporting information

C8

C9

0.0470 (17)

0.0404 (15)

0.0616 (18)

0.0244 (11)

0.0443 (17)

0.0447 (14)

0.0012 (14)

0.0007 (10)

0.0132 (13)

−0.0088 (11)

0.0092 (13)

0.0073 (10)

Geometric parameters (Å, º)

P1—O1

1.4687 (16)

C7—H7

0.94 (3)

P1—O2

P1—O3

P1—C1

1.5716 (16)

1.5754 (15)

1.815 (2)

1.464 (3)

1.465 (3)

1.384 (3)

1.395 (3)

1.501 (3)

1.413 (3)

0.98 (3)

1.384 (4)

1.386 (3)

1.493 (3)

1.379 (3)

1.388 (3)

0.97 (3)

1.379 (4)

0.93 (3)

1.520 (3)

1.0000

1.383 (4)

1.388 (3)

0.98 (3)

1.390 (3)

1.385 (3)

C4—H4

1.00 (3)

C17—C22

C17—C16

C19—C20

C19—H19

C6—H6

1.385 (3)

1.499 (3)

1.379 (4)

0.97 (3)

0.99 (3)

1.385 (4)

0.98 (3)

0.998 (17)

1.372 (4)

0.98 (3)

1.374 (4)

0.98 (3)

O2—C16

O3—C9

C5—C4

C5—C6

C5—C8

O4—C1

O4—H40

C10—C11

C10—C15

C10—C9

C3—C4

C3—C2

C3—H3

C11—C12

C11—H11

C1—C2

C1—H1

C18—C19

C18—C17

C18—H18

C2—C7

C7—C6

C22—C21

C22—H22

C16—H16A

C16—H16B

C15—C14

C15—H15

C21—C20

C21—H21

C20—H20

C13—C12

C13—C14

C13—H13

C12—H12

C14—H14

C8—H8A

C8—H8B

C8—H8C

C9—H9A

C9—H9B

0.90 (3)

1.365 (4)

1.370 (4)

0.94 (3)

0.91 (3)

0.96 (3)

0.930 (16)

0.930 (15)

1.024 (18)

O1—P1—O2

O1—P1—O3

O2—P1—O3

O1—P1—C1

O2—P1—C1

O3—P1—C1

C16—O2—P1

C9—O3—P1

C4—C5—C6

C4—C5—C8

C6—C5—C8

C1—O4—H40

C11—C10—C15

C11—C10—C9

C15—C10—C9

C4—C3—C2

115.37 (9)

112.66 (9)

103.06 (8)

115.99 (10)

102.59 (9)

105.77 (9)

118.73 (13)

119.27 (13)

117.9 (2)

121.1 (2)

121.0 (2)

104.4 (15)

119.2 (2)

C18—C19—H19

C7—C6—C5

C7—C6—H6

119.9

121.1 (2)

119.4

120.8 (2)

119.6

110.78 (19)

109.5

108.1

120.9 (3)

119.6

C5—C6—H6

C17—C22—C21

C17—C22—H22

C21—C22—H22

O2—C16—C17

O2—C16—H16A

C17—C16—H16A

O2—C16—H16B

C17—C16—H16B

H16A—C16—H16B

C14—C15—C10

C14—C15—H15

C10—C15—H15

119.3 (2)

121.5 (2)

120.8 (2)

Acta Cryst. (2019). C75, 283-293

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supporting information

C4—C3—H3

C2—C3—H3

C12—C11—C10

C12—C11—H11

C10—C11—H11

O4—C1—C2

O4—C1—P1

119.6

119.6 (3)

120.2

113.10 (19)

105.11 (14)

110.74 (14)

109.3

120.5 (2)

119.8

118.6 (2)

121.1 (2)

120.3 (2)

119.8

C20—C21—C22

C20—C21—H21

C22—C21—H21

C21—C20—C19

C21—C20—H20

C19—C20—H20

C12—C13—C14

C12—C13—H13

C14—C13—H13

C13—C12—C11

C13—C12—H12

C11—C12—H12

C13—C14—C15

C13—C14—H14

C15—C14—H14

C5—C8—H8A

C5—C8—H8B

H8A—C8—H8B

C5—C8—H8C

H8A—C8—H8C

H8B—C8—H8C

O3—C9—C10

120.0 (2)

120.0

119.8 (3)

120.1

120.9 (3)

119.6

120.3 (3)

119.8

119.2 (3)

120.4

109.5

C2—C1—P1

O4—C1—H1

C2—C1—H1

P1—C1—H1

C19—C18—C17

C19—C18—H18

C17—C18—H18

C3—C2—C7

C3—C2—C1

C7—C2—C1

C6—C7—C2

C6—C7—H7

C2—C7—H7

C3—C4—C5

119.8

121.2 (2)

119.4

C3—C4—H4

C5—C4—H4

C22—C17—C18

C22—C17—C16

C18—C17—C16

C20—C19—C18

C20—C19—H19

108.29 (18)

110.0

119.4

O3—C9—H9A

C10—C9—H9A

O3—C9—H9B

C10—C9—H9B

H9A—C9—H9B

118.6 (2)

119.5 (2)

121.9 (2)

120.3 (3)

119.9

108.4

O1—P1—O2—C16

O3—P1—O2—C16

C1—P1—O2—C16

O1—P1—O3—C9

O2—P1—O3—C9

C1—P1—O3—C9

C15—C10—C11—C12

C9—C10—C11—C12

O1—P1—C1—O4

O2—P1—C1—O4

O3—P1—C1—O4

O1—P1—C1—C2

O2—P1—C1—C2

O3—P1—C1—C2

C4—C3—C2—C7

C4—C3—C2—C1

O4—C1—C2—C3

P1—C1—C2—C3

O4—C1—C2—C7

48.40 (18)

−74.80 (17)

175.47 (16)

23.70 (19)

148.69 (16)

−103.97 (17)

−0.8 (4)

−178.4 (2)

55.39 (17)

−71.29 (16)

−178.96 (13)

−67.08 (17)

166.25 (15)

58.57 (17)

0.0 (3)

C8—C5—C4—C3

−178.7 (2)

C19—C18—C17—C22

C19—C18—C17—C16

C17—C18—C19—C20

C2—C7—C6—C5

C4—C5—C6—C7

C8—C5—C6—C7

C18—C17—C22—C21

C16—C17—C22—C21

P1—O2—C16—C17

C22—C17—C16—O2

C18—C17—C16—O2

C11—C10—C15—C14

C9—C10—C15—C14

C17—C22—C21—C20

C22—C21—C20—C19

C18—C19—C20—C21

C14—C13—C12—C11

C10—C11—C12—C13

−0.6 (3)

177.9 (2)

−0.1 (4)

1.0 (3)

−1.0 (3)

178.3 (2)

1.5 (3)

−177.0 (2)

−113.16 (18)

−136.4 (2)

45.1 (3)

1.3 (4)

178.9 (2)

−1.7 (4)

1.0 (4)

179.7 (2)

−20.6 (3)

97.0 (2)

159.11 (19)

−0.1 (4)

1.0 (4)

−0.4 (4)

Acta Cryst. (2019). C75, 283-293

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supporting information

P1—C1—C2—C7

C3—C2—C7—C6

C1—C2—C7—C6

C2—C3—C4—C5

C6—C5—C4—C3

−83.2 (2)

−0.4 (3)

179.8 (2)

0.0 (4)

C12—C13—C14—C15

−0.5 (4)

−0.7 (4)

175.76 (15)

−129.7 (2)

52.6 (3)

C10—C15—C14—C13

P1—O3—C9—C10

C11—C10—C9—O3

C15—C10—C9—O3

0.5 (3)

Dibenzyl [(3-chlorophenyl)(hydroxy)methyl]phosphonate (3b)

Crystal data

C₂₁H₂₀ClO₄P

M_r= 402.79

F(000) = 420

D_x= 1.393 Mg m⁻³

Monoclinic, P2₁

a = 10.4239 (8) Å

b = 7.8757 (5) Å

c = 12.0461 (7) Å

β = 103.775 (7)°

V = 960.49 (11) Å³

Z = 2

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 2191 reflections

θ = 4.4–25.4°

µ = 0.31 mm⁻¹

T = 133 K

Block, colorless

0.30 × 0.22 × 0.20 mm

Data collection

Agilent Xcalibur Sapphire3

diffractometer

Radiation source: Enhance (Mo) X-ray Source

Detector resolution: 15.9809 pixels mm^-1

ω scans

6934 measured reflections

3407 independent reflections

2955 reflections with I > 2σ(I)

R_int= 0.028

θ

_max= 26.4°, θ_min= 4.3°

Absorption correction: multi-scan

(CrysAlis PRO; Agilent, 2014)

h = −9→13

k = −8→9

T

_min= 0.991, T_max= 1.000

l = −15→15

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.047

wR(F²) = 0.114

H atoms treated by a mixture of independent

and constrained refinement

w = 1/[σ²(F_o²) + (0.0575P)²+ 0.2038P]

where P = (F_o²+ 2F_c²)/3

S = 1.05

3407 reflections

255 parameters

(Δ/σ)_max< 0.001

Δρ_max= 0.34 e Å⁻³

Δρ_min= −0.20 e Å⁻³

1 restraint

Hydrogen site location: inferred from

neighbouring sites

Absolute structure: Refined as an inversion twin

Absolute structure parameter: 0.35 (12)

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. Refined as a 2-component inversion twin

An Xcalibur, Sapphire3 detector equipped diffractometer was used with an Enhance Mo Kα X-ray radiation to collect all

the intensity data. The program CrysAlis PRO (CrysAlisPro, Agilent, 2014) was used for data collection, space group

determination and all data reduction purposes including empirical absorption correction using spherical harmonics. The

initial structure models were provided by direct methods using SHELXT (Sheldrick, 2015a) and refined using full-matrix

least-squares on F²using SHELXL (Sheldrick, 2015b). All non-H atoms were refined anisotropically.

Acta Cryst. (2019). C75, 283-293

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Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²)

x

y

z

U_iso*/U_eq

P1

Cl1

O2

O4

H4

0.39196 (10)

0.87251 (14)

0.4032 (3)

0.5090 (3)

0.5506

0.20951 (14)

0.3666 (2)

0.2610 (4)

0.2690 (5)

0.3370

0.13606 (8)

0.47865 (10)

0.2646 (2)

−0.0254 (2)

−0.0576

0.0314 (3)

0.0640 (4)

0.0368 (7)

0.0483 (9)

0.072*

O1

O3

C2

C3

H3

C9

C4

C5

0.3842 (3)

0.2705 (3)

0.6585 (4)

0.7023 (4)

0.652 (3)

0.4049 (4)

0.8229 (4)

0.9030 (5)

0.986 (5)

0.2867 (4)

0.2292

−0.0793 (4)

−0.1135 (18)

−0.1603 (5)

−0.245 (5)

0.2537 (5)

0.1733

0.0246 (4)

0.3148 (4)

0.2610 (5)

0.3308 (6)

0.410 (5)

0.2024 (6)

0.2798 (7)

0.1650 (6)

0.1341 (18)

0.2884 (7)

0.3133

0.2817 (6)

0.337 (3)

0.2497 (7)

0.2777 (18)

0.3374 (7)

0.3965

0.1175 (2)

0.0693 (3)

0.1657 (3)

0.2740 (4)

0.2999 (15)

0.4615 (3)

0.3431 (4)

0.3042 (4)

0.350 (3)

0.0404 (7)

0.0458 (8)

0.0315 (9)

0.0357 (9)

0.043*

0.0366 (9)

0.0405 (10)

0.0444 (12)

0.053*

0.0464 (11)

0.056*

0.0407 (10)

0.049*

0.0483 (12)

0.058*

0.0565 (14)

0.068*

0.0409 (11)

0.049*

0.0397 (11)

0.048*

H5

C14

H14

C21

H21

C20

H20

C13

H13

C10

H10

C17

H17

C1

0.4557 (4)

0.3837

−0.0668 (4)

−0.011 (3)

−0.1726 (4)

−0.1868 (9)

0.5567 (5)

0.5528

0.5690 (4)

0.5752

−0.1257 (4)

−0.1098 (9)

0.0922 (3)

0.0983

0.4860 (5)

0.5671

0.1022 (5)

0.192 (5)

0.5270 (4)

0.5172

0.1684 (6)

0.1100

0.1597 (6)

0.1288 (17)

0.3155 (6)

0.4412

0.0363 (10)

0.044*

H1

C16

C11

H11

C18

H18

C8

H8A

H8B

C15

H15A

H15B

C7

0.0516 (4)

0.4485 (5)

0.5044

0.2340 (6)

0.2199 (7)

0.1964

−0.0423 (3)

0.6674 (4)

0.7404

0.0364 (10)

0.0502 (12)

0.060*

0.0481 (12)

0.058*

0.0460 (11)

0.055*

0.0454 (12)

0.054*

0.0419 (10)

0.050*

0.0214 (5)

0.058 (2)

0.4424 (5)

0.548 (4)

0.3941 (17)

0.1368 (4)

0.0933 (15)

0.1420 (4)

0.7381 (4)

0.7094

0.1302 (7)

0.079 (3)

0.1376 (6)

0.1175 (10)

0.018 (4)

0.2643 (7)

0.364 (3)

0.149 (4)

0.1431 (6)

0.0942

−0.2335 (4)

−0.292 (3)

0.3573 (4)

0.3753 (7)

0.3320 (9)

0.0766 (4)

0.1186 (15)

0.1272 (18)

0.1276 (4)

0.0538

H7

C19

H19

C6

−0.1103 (5)

−0.164 (3)

0.8590 (5)

0.918 (3)

0.1741 (7)

0.1531 (14)

0.0974 (6)

0.009 (5)

−0.2565 (4)

−0.327 (4)

0.1974 (4)

0.1677 (16)

0.0494 (13)

0.059*

0.0470 (12)

0.056*

H6

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supporting information

C12

H12

0.3337 (6)

0.3088

0.3025 (8)

0.3365

0.6596 (5)

0.7272

0.0594 (15)

0.071*

Atomic displacement parameters (Å²)

U¹¹

U²²

U³³

U¹²

U¹³

U²³

P1

Cl1

O2

O4

O1

O3

C2

C3

C9

0.0336 (5)

0.0613 (8)

0.0463 (17)

0.060 (2)

0.0498 (19)

0.0353 (16)

0.030 (2)

0.032 (2)

0.046 (2)

0.039 (2)

0.034 (2)

0.043 (3)

0.041 (2)

0.036 (2)

0.049 (3)

0.042 (2)

0.039 (2)

0.033 (2)

0.072 (3)

0.060 (3)

0.063 (3)

0.036 (2)

0.044 (3)

0.055 (3)

0.043 (3)

0.080 (4)

0.0304 (6)

0.0802 (11)

0.0322 (17)

0.056 (2)

0.0327 (18)

0.047 (2)

0.031 (2)

0.030 (2)

0.041 (3)

0.032 (3)

0.042 (3)

0.035 (3)

0.047 (3)

0.045 (3)

0.033 (3)

0.042 (3)

0.037 (3)

0.036 (3)

0.042 (3)

0.037 (3)

0.059 (3)

0.038 (3)

0.047 (3)

0.034 (3)

0.055 (4)

0.0304 (5)

−0.0026 (4)

−0.0028 (7)

0.0037 (12)

−0.0126 (16)

−0.0045 (14)

−0.0061 (16)

−0.0003 (17)

−0.010 (2)

−0.0078 (19)

−0.0012 (18)

0.000 (2)

0.0082 (4)

−0.0065 (5)

0.0154 (12)

0.0151 (14)

0.0149 (14)

0.0029 (13)

0.0123 (16)

0.0084 (18)

0.0198 (18)

0.0048 (18)

0.012 (2)

0.008 (2)

0.020 (2)

0.007 (2)

0.038 (3)

0.0109 (19)

0.0093 (18)

0.0087 (17)

0.0114 (17)

0.014 (2)

0.0004 (4)

−0.0050 (6)

0.0014 (12)

−0.0007 (14)

−0.0031 (13)

0.0120 (15)

0.0046 (16)

0.0003 (18)

−0.005 (2)

0.0057 (19)

0.011 (2)

0.0410 (6)

0.0348 (14)

0.0313 (15)

0.0408 (16)

0.0509 (17)

0.0358 (19)

0.046 (2)

0.038 (2)

0.039 (2)

0.067 (3)

0.053 (3)

0.051 (3)

0.059 (3)

0.086 (4)

0.048 (2)

0.039 (2)

0.033 (2)

0.041 (2)

0.038 (2)

0.045 (2)

0.043 (2)

0.045 (2)

0.048 (2)

0.039 (2)

0.070 (3)

0.055 (3)

C4

C5

C14

C21

C20

C13

C10

C17

C1

C16

C11

C18

C8

−0.002 (2)

0.003 (2)

0.005 (2)

0.0006 (19)

0.002 (2)

−0.008 (2)

−0.0031 (18)

0.0072 (19)

−0.0066 (19)

−0.0009 (18)

−0.021 (3)

0.002 (2)

−0.015 (3)

0.0041 (18)

0.0051 (18)

0.0011 (17)

0.0069 (19)

−0.005 (2)

0.010 (2)

0.001 (2)

−0.0059 (19)

0.001 (2)

−0.001 (2)

−0.022 (3)

0.019 (2)

0.022 (2)

0.0163 (19)

0.019 (2)

−0.003 (2)

0.026 (2)

0.014 (2)

C15

C7

C19

C6

−0.002 (2)

−0.007 (2)

−0.006 (2)

0.001 (2)

C12

−0.022 (3)

0.038 (3)

Geometric parameters (Å, º)

P1—O1

P1—O3

P1—O2

P1—C1

Cl1—C4

O2—C8

O4—C1

O4—H4

O3—C15

C2—C3

C2—C7

C2—C1

1.473 (3)

C20—C19

1.378 (7)

1.566 (3)

1.578 (3)

1.819 (4)

1.732 (5)

1.463 (5)

1.432 (5)

0.8400

1.472 (5)

1.389 (6)

1.394 (6)

1.506 (6)

C20—H20

C13—C12

C13—H13

C10—C11

C10—H10

C17—C16

C17—C18

C17—H17

C1—H1

0.88 (5)

1.347 (8)

0.9500

1.394 (6)

0.9500

1.372 (6)

1.389 (6)

0.94 (5)

1.0000

1.514 (6)

1.346 (8)

C16—C15

C11—C12

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C3—C4

C3—H3

C9—C14

C9—C10

C9—C8

C4—C5

C5—C6

C5—H5

C14—C13

C14—H14

C21—C20

C21—C16

C21—H21

1.391 (6)

0.92 (5)

1.393 (6)

1.492 (6)

1.386 (7)

1.367 (7)

0.94 (5)

1.395 (7)

0.9500

C11—H11

C18—C19

C18—H18

C8—H8A

C8—H8B

C15—H15A

C15—H15B

C7—C6

0.9500

1.379 (7)

0.97 (5)

1.08 (4)

1.09 (4)

1.386 (7)

0.9500

C7—H7

C19—H19

C6—H6

0.92 (5)

1.04 (5)

0.9500

1.374 (7)

1.377 (6)

0.94 (5)

C12—H12

O1—P1—O3

O1—P1—O2

O3—P1—O2

O1—P1—C1

O3—P1—C1

O2—P1—C1

115.92 (18)

113.06 (17)

103.29 (17)

115.33 (19)

101.24 (19)

106.57 (18)

121.3 (3)

109.5

119.2 (3)

119.0 (4)

119.3 (4)

121.7 (4)

119.7 (4)

120.2

C18—C17—H17

O4—C1—C2

O4—C1—P1

C2—C1—P1

O4—C1—H1

119.9

113.3 (3)

104.0 (3)

110.9 (3)

109.5

119.6 (4)

121.2 (4)

119.2 (4)

120.4 (5)

119.8

119.9 (5)

120.0

109.5 (4)

109.8

108.2

109.7 (3)

109.7

C2—C1—H1

P1—C1—H1

C8—O2—P1

C1—O4—H4

C15—O3—P1

C3—C2—C7

C3—C2—C1

C7—C2—C1

C2—C3—C4

C2—C3—H3

C4—C3—H3

C14—C9—C10

C14—C9—C8

C10—C9—C8

C5—C4—C3

C5—C4—Cl1

C3—C4—Cl1

C6—C5—C4

C6—C5—H5

C4—C5—H5

C9—C14—C13

C9—C14—H14

C13—C14—H14

C20—C21—C16

C20—C21—H21

C16—C21—H21

C21—C20—C19

C21—C20—H20

C19—C20—H20

C12—C13—C14

C17—C16—C21

C17—C16—C15

C21—C16—C15

C12—C11—C10

C12—C11—H11

C10—C11—H11

C19—C18—C17

C19—C18—H18

C17—C18—H18

O2—C8—C9

O2—C8—H8A

C9—C8—H8A

O2—C8—H8B

C9—C8—H8B

H8A—C8—H8B

O3—C15—C16

O3—C15—H15A

C16—C15—H15A

O3—C15—H15B

C16—C15—H15B

H15A—C15—H15B

C6—C7—C2

120.2

118.3 (4)

122.0 (4)

119.6 (4)

121.2 (4)

120.5 (4)

118.3 (4)

118.6 (5)

120.7

119.3 (5)

120.3

120.5 (4)

119.8

109.7

108.2

120.0 (4)

120.0

119.5 (4)

120.2

119.8

120.3 (4)

119.9

121.2 (5)

C6—C7—H7

C2—C7—H7

C20—C19—C18

C20—C19—H19

C18—C19—H19

120.2

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supporting information

C12—C13—H13

C14—C13—H13

C9—C10—C11

C9—C10—H10

C11—C10—H10

C16—C17—C18

C16—C17—H17

119.4

120.3 (5)

119.9

C5—C6—C7

C5—C6—H6

C7—C6—H6

C11—C12—C13

C11—C12—H12

C13—C12—H12

121.5 (4)

119.2

120.5 (5)

119.7

120.2 (4)

119.9

O1—P1—O2—C8

O3—P1—O2—C8

C1—P1—O2—C8

O1—P1—O3—C15

O2—P1—O3—C15

C1—P1—O3—C15

C7—C2—C3—C4

C1—C2—C3—C4

C2—C3—C4—C5

C2—C3—C4—Cl1

C3—C4—C5—C6

Cl1—C4—C5—C6

C10—C9—C14—C13

C8—C9—C14—C13

C16—C21—C20—C19

C9—C14—C13—C12

C14—C9—C10—C11

C8—C9—C10—C11

C3—C2—C1—O4

C7—C2—C1—O4

C3—C2—C1—P1

C7—C2—C1—P1

O1—P1—C1—O4

O3—P1—C1—O4

17.5 (4)

143.6 (3)

−110.2 (3)

51.4 (4)

−72.8 (3)

177.0 (3)

−1.3 (6)

179.3 (4)

2.5 (6)

−178.7 (3)

−2.3 (7)

178.9 (3)

0.1 (7)

176.4 (5)

−2.0 (7)

−0.3 (8)

0.0 (7)

−176.4 (4)

164.9 (4)

−14.5 (6)

−78.6 (4)

102.0 (4)

55.6 (3)

−70.4 (3)

O2—P1—C1—O4

O1—P1—C1—C2

O3—P1—C1—C2

O2—P1—C1—C2

C18—C17—C16—C21

C18—C17—C16—C15

C20—C21—C16—C17

C20—C21—C16—C15

C9—C10—C11—C12

C16—C17—C18—C19

P1—O2—C8—C9

C14—C9—C8—O2

C10—C9—C8—O2

P1—O3—C15—C16

C17—C16—C15—O3

C21—C16—C15—O3

C3—C2—C7—C6

−178.1 (3)

−66.5 (3)

167.5 (3)

59.8 (3)

−1.1 (7)

178.7 (4)

2.4 (7)

−177.4 (5)

0.1 (7)

−0.7 (7)

−162.5 (3)

39.0 (6)

−144.8 (4)

−124.0 (4)

37.6 (6)

−142.6 (4)

−0.1 (6)

179.4 (4)

0.2 (8)

1.1 (8)

0.9 (7)

0.2 (7)

−0.3 (8)

0.4 (8)

C1—C2—C7—C6

C21—C20—C19—C18

C17—C18—C19—C20

C4—C5—C6—C7

C2—C7—C6—C5

C10—C11—C12—C13

C14—C13—C12—C11

Dibenzyl [hydroxy(2-nitrophenyl)methyl]phosphonate (3a)

Crystal data

C₂₁H₂₀NO₆P

Z = 4

M_r= 413.35

Triclinic, P1

F(000) = 864

D_x= 1.390 Mg m⁻³

a = 10.0795 (3) Å

b = 13.8530 (6) Å

c = 15.9354 (5) Å

α = 111.110 (4)°

β = 90.852 (3)°

γ = 106.326 (3)°

V = 1975.23 (13) Å³

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 8023 reflections

θ = 4.2–31.4°

µ = 0.18 mm⁻¹

T = 133 K

Block, colorless

0.43 × 0.30 × 0.25 mm

Acta Cryst. (2019). C75, 283-293

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supporting information

Data collection

Agilent Xcalibur Sapphire3

diffractometer

Radiation source: Enhance (Mo) X-ray Source

Detector resolution: 15.9809 pixels mm^-1

ω scans

39828 measured reflections

11989 independent reflections

8512 reflections with I > 2σ(I)

R_int= 0.038

θ

_max= 30.5°, θ_min= 4.2°

Absorption correction: multi-scan

(CrysAlis PRO; Agilent, 2014)

h = −14→14

k = −19→19

l = −22→22

T

_min= 0.980, T_max= 1.000

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.046

wR(F²) = 0.124

S = 1.03

Hydrogen site location: mixed

H atoms treated by a mixture of independent

and constrained refinement

w = 1/[σ²(F_o²) + (0.0527P)²+ 0.5554P]

where P = (F_o²+ 2F_c²)/3

11989 reflections

565 parameters

0 restraints

(Δ/σ)_max< 0.001

Δρ_max= 0.60 e Å⁻³

Δρ_min= −0.30 e Å⁻³