L-Phenyl­alanine L-phenyl­alaninium di­hydrogenphosphate

In the title compound, C₉H₁₁NO₂·C₉H₁₂NO₂⁺·H₂PO₄⁻, the di­hydrogenphosphate anion links the phenyl­alaninium and zwitterionic phenyl­alanine residues via strong O—H...O hydrogen bonds. A three-centered hydrogen bond is observed in the phenyl­alaninium residue. This aggregation results in the formation of hydro­philic layers that are sandwiched between hydro­phobic layers. Both S2 and Z1 head-to-tail sequences are observed.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.016 Å
• R factor = 0.063
• wR factor = 0.184
• Data-to-parameter ratio = 9.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           25.00
         From the CIF: _reflns_number_total               2439
         Count of symmetry unique reflns         2001
         Completeness (_total/calc)            121.89%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       438
         Fraction of Friedel pairs measured     0.219
         Are heavy atom types Z>Si present          yes
          WARNING: Large fraction of Friedel related reflns may
                   be needed to determine absolute structure

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Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.

'L-phenylalanine L-phenylalanium dihydrogen phosphate'

Crystal data

C9H11NO2·C9H12NO2^+·H2PO4^−	F(000) = 452
Mr = 428.37	Dx = 1.414 Mg m^−3 Dm = 1.41 Mg m^−3 Dm measured by flotation using a mixture of carbon tetrachloride and xylene
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 25 reflections
a = 13.441 (1) Å	θ = 8.5–13.9°
b = 4.8760 (4) Å	µ = 0.19 mm^−1
c = 15.470 (2) Å	T = 293 K
β = 97.12 (1)°	Needle, colorless
V = 1006.06 (17) Å^3	0.6 × 0.13 × 0.10 mm
Z = 2

Data collection

Enraf-Nonius CAD-4 diffractometer	1167 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.064
Graphite monochromator	θmax = 25.0°, θmin = 1.5°
ω–2θ scans	h = −1→15
Absorption correction: ψ scan (North et al., 1968)	k = −1→5
Tmin = 0.972, Tmax = 0.982	l = −18→18
2762 measured reflections	3 standard reflections every 60 min
2439 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.063	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.184	w = 1/[σ^2(Fo^2) + (0.0874P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.97	(Δ/σ)max < 0.001
2439 reflections	Δρmax = 0.31 e Å^−3
267 parameters	Δρmin = −0.34 e Å^−3
49 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.2 (4)

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
P1	0.77004 (17)	0.1971 (6)	0.45109 (16)	0.0295 (7)
O1	0.8746 (4)	0.2720 (13)	0.4371 (4)	0.0324 (18)
O3	0.7658 (4)	0.0876 (16)	0.5437 (4)	0.0406 (19)
H3	0.8009	−0.0499	0.5515	0.061*
O2	0.6962 (4)	0.4365 (15)	0.4406 (4)	0.0374 (19)
O4	0.7345 (5)	−0.0360 (15)	0.3853 (4)	0.041 (2)
H4	0.6771	−0.0809	0.3916	0.061*
O1A	1.1033 (4)	1.2209 (16)	0.4150 (4)	0.0377 (17)
O1B	1.1757 (4)	1.1159 (16)	0.2984 (4)	0.041 (2)
C11	1.1129 (6)	1.086 (2)	0.3489 (6)	0.030 (2)
C12	1.0363 (7)	0.850 (2)	0.3259 (5)	0.032 (3)
H12	1.0723	0.6850	0.3116	0.038*
N11	0.9841 (5)	0.7951 (16)	0.4034 (4)	0.028 (2)
H11A	0.9407	0.6584	0.3917	0.041*
H11B	0.9515	0.9451	0.4168	0.041*
H11C	1.0290	0.7489	0.4483	0.041*
C13	0.9623 (7)	0.932 (2)	0.2478 (6)	0.041 (3)
H13A	0.9136	1.0565	0.2677	0.050*
H13B	0.9985	1.0337	0.2077	0.050*
C14	0.9068 (6)	0.705 (2)	0.1986 (6)	0.033 (2)
C15	0.8178 (8)	0.615 (3)	0.2212 (8)	0.059 (4)
H15	0.7938	0.6952	0.2691	0.071*
C16	0.7613 (10)	0.412 (3)	0.1772 (9)	0.079 (4)
H16	0.7026	0.3479	0.1964	0.095*
C17	0.7938 (13)	0.310 (3)	0.1064 (9)	0.086 (5)
H17	0.7540	0.1806	0.0746	0.104*
C18	0.8835 (13)	0.385 (3)	0.0763 (7)	0.083 (5)
H18	0.9059	0.3043	0.0278	0.100*
C19	0.9380 (10)	0.593 (3)	0.1260 (7)	0.070 (4)
H19	0.9975	0.6562	0.1081	0.084*
O2A	0.5386 (4)	0.8742 (15)	0.4462 (4)	0.041 (2)
O2B	0.5193 (5)	0.5003 (15)	0.3635 (4)	0.0336 (19)
H2B	0.578 (8)	0.47 (3)	0.392 (6)	0.06 (4)*
C21	0.4904 (6)	0.738 (3)	0.3897 (6)	0.028 (3)
C22	0.3946 (6)	0.841 (2)	0.3424 (5)	0.025 (2)
H22	0.3437	0.6961	0.3401	0.030*
N21	0.3623 (5)	1.0778 (17)	0.3910 (5)	0.032 (2)
H21A	0.3045	1.1418	0.3643	0.049*
H21B	0.4087	1.2088	0.3932	0.049*
H21C	0.3542	1.0261	0.4449	0.049*
C23	0.4090 (7)	0.927 (2)	0.2500 (5)	0.035 (3)
H23A	0.3633	1.0771	0.2326	0.042*
H23B	0.4767	0.9963	0.2503	0.042*
C24	0.3918 (7)	0.703 (3)	0.1831 (5)	0.035 (2)
C25	0.2988 (8)	0.601 (3)	0.1599 (7)	0.056 (4)
H25	0.2457	0.6704	0.1864	0.068*
C26	0.2799 (11)	0.396 (3)	0.0977 (8)	0.071 (4)
H26	0.2155	0.3268	0.0837	0.086*
C27	0.3567 (14)	0.300 (3)	0.0577 (8)	0.076 (4)
H27	0.3450	0.1644	0.0154	0.091*
C28	0.4515 (12)	0.400 (3)	0.0793 (7)	0.068 (4)
H28	0.5045	0.3319	0.0525	0.081*
C29	0.4675 (9)	0.605 (3)	0.1413 (7)	0.055 (3)
H29	0.5316	0.6767	0.1548	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0208 (12)	0.0254 (16)	0.0424 (14)	0.0070 (16)	0.0049 (10)	−0.0021 (16)
O1	0.019 (3)	0.015 (5)	0.065 (4)	0.001 (3)	0.013 (3)	0.004 (3)
O3	0.030 (4)	0.034 (5)	0.058 (4)	0.021 (4)	0.008 (3)	−0.003 (4)
O2	0.022 (3)	0.030 (5)	0.059 (4)	0.016 (4)	−0.001 (3)	−0.002 (4)
O4	0.039 (4)	0.034 (5)	0.051 (4)	−0.007 (4)	0.013 (3)	−0.013 (4)
O1A	0.029 (3)	0.028 (5)	0.057 (4)	−0.013 (4)	0.010 (3)	−0.015 (4)
O1B	0.028 (3)	0.047 (6)	0.050 (4)	−0.008 (4)	0.009 (3)	0.003 (4)
C11	0.026 (5)	0.023 (6)	0.038 (5)	0.001 (5)	−0.003 (5)	0.010 (5)
C12	0.029 (5)	0.027 (7)	0.038 (5)	−0.003 (5)	0.004 (4)	−0.008 (5)
N11	0.017 (3)	0.011 (5)	0.052 (4)	−0.002 (4)	−0.006 (3)	−0.004 (4)
C13	0.044 (6)	0.023 (7)	0.054 (6)	0.000 (6)	−0.008 (5)	0.008 (6)
C14	0.037 (5)	0.016 (6)	0.042 (5)	0.006 (7)	−0.006 (4)	0.002 (6)
C15	0.047 (7)	0.039 (9)	0.085 (8)	0.005 (7)	−0.016 (6)	−0.019 (7)
C16	0.057 (8)	0.070 (11)	0.097 (9)	−0.006 (8)	−0.039 (8)	−0.013 (10)
C17	0.123 (12)	0.053 (10)	0.067 (9)	−0.014 (10)	−0.055 (9)	0.004 (8)
C18	0.146 (14)	0.058 (11)	0.040 (7)	0.026 (11)	−0.007 (9)	−0.019 (8)
C19	0.101 (9)	0.064 (10)	0.044 (6)	0.011 (9)	0.009 (6)	−0.008 (7)
O2A	0.027 (4)	0.022 (5)	0.069 (4)	0.006 (4)	−0.011 (3)	0.003 (4)
O2B	0.022 (4)	0.024 (5)	0.054 (4)	0.007 (4)	0.003 (3)	−0.006 (4)
C21	0.015 (4)	0.029 (8)	0.038 (5)	−0.015 (6)	−0.001 (4)	−0.004 (6)
C22	0.022 (5)	0.012 (6)	0.042 (5)	0.003 (5)	0.006 (4)	−0.012 (5)
N21	0.022 (4)	0.023 (5)	0.052 (5)	0.000 (4)	0.003 (4)	0.008 (4)
C23	0.044 (6)	0.027 (7)	0.033 (5)	0.003 (6)	0.003 (5)	0.014 (5)
C24	0.048 (6)	0.025 (6)	0.031 (5)	−0.003 (7)	0.004 (4)	0.000 (6)
C25	0.056 (7)	0.050 (9)	0.057 (7)	0.018 (7)	−0.016 (6)	0.000 (7)
C26	0.085 (10)	0.050 (10)	0.071 (8)	−0.013 (9)	−0.024 (8)	−0.003 (8)
C27	0.152 (13)	0.022 (8)	0.047 (7)	0.011 (9)	−0.010 (9)	−0.003 (6)
C28	0.108 (11)	0.041 (9)	0.061 (8)	0.016 (9)	0.037 (8)	0.000 (8)
C29	0.073 (8)	0.031 (8)	0.065 (7)	0.002 (7)	0.024 (6)	−0.009 (7)

Geometric parameters (Å, º)

P1—O1	1.494 (5)	C18—H18	0.9300
P1—O2	1.528 (7)	C19—H19	0.9300
P1—O3	1.537 (7)	O2A—C21	1.217 (10)
P1—O4	1.560 (7)	O2B—C21	1.305 (13)
O3—H3	0.8200	O2B—H2B	0.87 (10)
O4—H4	0.8200	C21—C22	1.486 (11)
O1A—C11	1.235 (11)	C22—N21	1.474 (11)
O1B—C11	1.228 (10)	C22—C23	1.526 (11)
C11—C12	1.556 (14)	C22—H22	0.9800
C12—N11	1.487 (10)	N21—H21A	0.8900
C12—C13	1.520 (12)	N21—H21B	0.8900
C12—H12	0.9800	N21—H21C	0.8900
N11—H11A	0.8900	C23—C24	1.504 (14)
N11—H11B	0.8900	C23—H23A	0.9700
N11—H11C	0.8900	C23—H23B	0.9700
C13—C14	1.493 (13)	C24—C25	1.352 (13)
C13—H13A	0.9700	C24—C29	1.358 (13)
C13—H13B	0.9700	C25—C26	1.387 (17)
C14—C19	1.358 (14)	C25—H25	0.9300
C14—C15	1.360 (13)	C26—C27	1.351 (17)
C15—C16	1.377 (17)	C26—H26	0.9300
C15—H15	0.9300	C27—C28	1.367 (18)
C16—C17	1.323 (17)	C27—H27	0.9300
C16—H16	0.9300	C28—C29	1.381 (16)
C17—C18	1.392 (18)	C28—H28	0.9300
C17—H17	0.9300	C29—H29	0.9300
C18—C19	1.423 (18)
O1—P1—O2	114.1 (4)	C14—C19—C18	122.7 (13)
O1—P1—O3	111.4 (3)	C14—C19—H19	118.6
O2—P1—O3	105.4 (4)	C18—C19—H19	118.6
O1—P1—O4	107.5 (4)	C21—O2B—H2B	107 (8)
O2—P1—O4	110.2 (4)	O2A—C21—O2B	123.7 (9)
O3—P1—O4	108.1 (4)	O2A—C21—C22	121.5 (10)
P1—O3—H3	109.5	O2B—C21—C22	114.8 (8)
P1—O4—H4	109.5	N21—C22—C21	107.7 (7)
O1B—C11—O1A	128.0 (10)	N21—C22—C23	109.9 (8)
O1B—C11—C12	115.4 (9)	C21—C22—C23	110.6 (7)
O1A—C11—C12	116.6 (8)	N21—C22—H22	109.5
N11—C12—C13	111.2 (7)	C21—C22—H22	109.5
N11—C12—C11	108.3 (7)	C23—C22—H22	109.5
C13—C12—C11	109.6 (8)	C22—N21—H21A	109.5
N11—C12—H12	109.2	C22—N21—H21B	109.5
C13—C12—H12	109.2	H21A—N21—H21B	109.5
C11—C12—H12	109.2	C22—N21—H21C	109.5
C12—N11—H11A	109.5	H21A—N21—H21C	109.5
C12—N11—H11B	109.5	H21B—N21—H21C	109.5
H11A—N11—H11B	109.5	C24—C23—C22	114.6 (9)
C12—N11—H11C	109.5	C24—C23—H23A	108.6
H11A—N11—H11C	109.5	C22—C23—H23A	108.6
H11B—N11—H11C	109.5	C24—C23—H23B	108.6
C14—C13—C12	116.5 (9)	C22—C23—H23B	108.6
C14—C13—H13A	108.2	H23A—C23—H23B	107.6
C12—C13—H13A	108.2	C25—C24—C29	117.8 (11)
C14—C13—H13B	108.2	C25—C24—C23	120.5 (9)
C12—C13—H13B	108.2	C29—C24—C23	121.6 (9)
H13A—C13—H13B	107.3	C24—C25—C26	122.1 (12)
C19—C14—C15	117.2 (11)	C24—C25—H25	118.9
C19—C14—C13	122.1 (10)	C26—C25—H25	118.9
C15—C14—C13	120.5 (10)	C27—C26—C25	118.9 (13)
C14—C15—C16	123.5 (12)	C27—C26—H26	120.6
C14—C15—H15	118.2	C25—C26—H26	120.6
C16—C15—H15	118.2	C26—C27—C28	120.4 (13)
C17—C16—C15	117.3 (14)	C26—C27—H27	119.8
C17—C16—H16	121.3	C28—C27—H27	119.8
C15—C16—H16	121.3	C27—C28—C29	119.2 (12)
C16—C17—C18	124.6 (14)	C27—C28—H28	120.4
C16—C17—H17	117.7	C29—C28—H28	120.4
C18—C17—H17	117.7	C24—C29—C28	121.5 (12)
C17—C18—C19	114.5 (12)	C24—C29—H29	119.2
C17—C18—H18	122.8	C28—C29—H29	119.2
C19—C18—H18	122.8
O1B—C11—C12—N11	165.4 (8)	O2A—C21—C22—N21	−14.1 (11)
O1A—C11—C12—N11	−14.7 (11)	O2B—C21—C22—N21	168.4 (8)
O1B—C11—C12—C13	−73.1 (11)	O2A—C21—C22—C23	106.0 (10)
O1A—C11—C12—C13	106.8 (10)	O2B—C21—C22—C23	−71.5 (11)
N11—C12—C13—C14	−80.3 (11)	N21—C22—C23—C24	−151.4 (8)
C11—C12—C13—C14	159.9 (9)	C21—C22—C23—C24	89.8 (10)
C12—C13—C14—C19	−95.8 (12)	C22—C23—C24—C25	68.7 (13)
C12—C13—C14—C15	89.5 (12)	C22—C23—C24—C29	−114.4 (11)
C19—C14—C15—C16	3.0 (18)	C29—C24—C25—C26	2.2 (18)
C13—C14—C15—C16	178.0 (10)	C23—C24—C25—C26	179.2 (10)
C14—C15—C16—C17	−4 (2)	C24—C25—C26—C27	−1.4 (19)
C15—C16—C17—C18	4 (2)	C25—C26—C27—C28	1 (2)
C16—C17—C18—C19	−3 (2)	C26—C27—C28—C29	−1 (2)
C15—C14—C19—C18	−2.3 (17)	C25—C24—C29—C28	−2.4 (17)
C13—C14—C19—C18	−177.1 (10)	C23—C24—C29—C28	−179.3 (10)
C17—C18—C19—C14	2.1 (19)	C27—C28—C29—C24	1.8 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O1A^i	0.82	1.74	2.535 (9)	164
O4—H4···O2A^ii	0.82	2.15	2.938 (9)	162
N11—H11A···O1	0.89	2.23	3.022 (10)	148
N11—H11B···O1^iii	0.89	1.95	2.834 (10)	176
N11—H11C···O1^iv	0.89	2.07	2.923 (8)	161
O2B—H2B···O2	0.87 (10)	1.68 (10)	2.543 (9)	172 (12)
N21—H21A···O1B^v	0.89	1.90	2.736 (9)	156
N21—H21B···O2B^iii	0.89	2.15	3.017 (10)	165
N21—H21B···O2A^vi	0.89	2.62	3.062 (9)	111
N21—H21C···O2^vi	0.89	2.02	2.896 (9)	167

Symmetry codes: (i) −x+2, y−3/2, −z+1; (ii) x, y−1, z; (iii) x, y+1, z; (iv) −x+2, y+1/2, −z+1; (v) x−1, y, z; (vi) −x+1, y+1/2, −z+1.