1,3-Bis[(5-amino­furan-2-yl)meth­yl]-3,4,5,6-tetra­hydro­pyrimidin-1-ium hexa­fluoro­phosphate

The asymmetric unit of the title salt, C₁₆H₂₁N₂O₂⁺·PF₆⁻, contains half of the whole ion pair, which has crystallographic mirror symmetry. Two F atoms related by the mirror plane are disordered over two sites of equal occupancy. The dihedral angle between the central ring and the furan ring is 59.3 ()°. In the crystal, the anions and cations are linked through C—H...F inter­actions, forming a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.007 Å
• Disorder in solvent or counterion
• R factor = 0.077
• wR factor = 0.247
• Data-to-parameter ratio = 11.6

checkCIF/PLATON results

No syntax errors found



Alert level C
THETM01_ALERT_3_C  The value of sine(theta_max)/wavelength is less than 0.590
            Calculated sin(theta_max)/wavelength =    0.5888
PLAT234_ALERT_4_C Large Hirshfeld Difference P1     --  F3      ..       0.17 Ang.
PLAT234_ALERT_4_C Large Hirshfeld Difference P1     --  F5      ..       0.19 Ang.
PLAT234_ALERT_4_C Large Hirshfeld Difference P1     --  F6      ..       0.19 Ang.
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors of          P1
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.9
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0073 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.589         30

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ? Do !
PLAT072_ALERT_2_G SHELXL First  Parameter in WGHT Unusually Large.       0.14
PLAT302_ALERT_4_G Note: Anion/Solvent Disorder ...................         29 %

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   8 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

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

---

S1. Comment

1,3-Di(5-methylfurfuryl)pyrimidinium hexafluorophosphate salt is conventional N-heterocyclic carbene (NHC) precursors. N-heterocyclic carbenes (NHCs) are generally considered as analogues of phosphine ligands because of their good s-donating but very weak p-accepting ability (Arduengo et al., 1992). Normally, NHC-metal complexes have higher stability toward heat, moisture, and oxygen than phosphine metal based complexes, which makes them quite attractive as phosphine substitute. In recent years, NHCs are fully used as organocatalysts and ancillary ligands in transition metal catalyzed reactions (Hermann, 2002). They have attracted many attention, particularly for its functions in catalytic reactions (Akkoç & Gök, 2013; Lee et al., 2013; Bagherzadeh et al., 2012; Çetinkaya et al., 1997; Özdemir et al., 2001; Saba et al., 1991; Yiğit et al., 2007).

Fig. 1 shows the whole molecule (I) whose anions and cations form two parts with a crystallographic mirror symmetry. The C1–N1–C2–C3, C1–N1–C4–C5, C2–N1–C4–C5, N1–C4–C5–O1 and N1–C4–C5–C6 torsion angles are -25.1 (6), -121.5 (4), 60.4 (5), -85.1 (4) and 96.4 (6) °, respectively. All bond lengths of (I) are within normal values (Allen et al., 1987).

The crystal structure is stabilized by C—H···F interactions between the anions and cations of (I), forming a three dimensional network (Table 1, Figures 2 and 3).

Related literature

N-heterocyclic carbene (NHC)-metal complexes have attracted much attention, particularly for their functions in catalytic reactions, see: Akkoç & Gök (2013); Arduengo et al. (1992); Bagherzadeh et al. (2012); Hermann (2002); Lee et al. (2013); Saba et al. (1991); Yiğit et al. (2007); Özdemir et al. (2001); Çetinkaya et al. (1997). For bond-length data, see: Allen et al. (1987).

S2. Experimental

The reaction for the preparation of heterocyclic salt containing furan moiety was carried out under argon in flame dried glassware using standard Schlenk type flasks. The synthesis of salt containing furan moiety was achieved by the reaction of N,N'-dialkylpropane-1,3-diamine (1.0 mmol) with ammonium hexafluorophosphate (1.0 mmol) in triethyl orthoformate (5 ml) (Scheme 1). The reaction mixture was heated for 12 h at 353 K. A white solid was precipitated. The precipitation was then crystallized from Et₂O/EtOH (2:1) at room temperature. The resulting 1,3-di(5-methylfurfuryl)pyrimidinium hexafluorophosphate salt was obtained in good yield.

S3. Refinement

All H atoms were positioned geometrically and refined by using a riding model, with C—H = 0.93 - 0.97 Å and U_iso(H) = 1.2 or 1.5U_eq(C). The one fluoride atom of the hexafluorophosphate group are disordered over two sites as F5 and F6 in Fig. 1, with equal occupancies of 0.5. Mirror symmetry transformation generates the other equivalent disordered atoms (F5a and F6a in Fig. 1).

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures

	Fig. 1. View of the title compound with a crystallographic mirror symmetry. Displacement ellipsoids are shown at the 20% probability levels. The disordered F5, F6 and F5a, F5b atoms are related to each other with a mirror symmetry operation. Symmetry codes: (a) x, 1/2 - y, z; (b) x, 1/2 - y, z.
	Fig. 2. View of the crystal packing and the hydrogen bonding of (I) along a axis. H atoms not involved in hydrogen bonding are omitted for clarity.
	Fig. 3. View of the crystal packing and the hydrogen bonding of (I) along c axis. H atoms not involved in hydrogen bonding are omitted for clarity.

1,3-Bis[(5-aminofuran-2-yl)methyl]-3,4,5,6-tetrahydropyrimidin-1-ium hexafluorophosphate

Crystal data

C16H21N2O2^+·PF6^−	F(000) = 432
Mr = 418.32	Dx = 1.437 Mg m^−3
Monoclinic, P21/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yb	Cell parameters from 1100 reflections
a = 6.0793 (6) Å	θ = 2.5–25°
b = 18.879 (2) Å	µ = 0.21 mm^−1
c = 8.5750 (9) Å	T = 296 K
β = 100.747 (5)°	Prism, colourless
V = 966.90 (17) Å^3	0.35 × 0.28 × 0.23 mm
Z = 2

Data collection

Bruker Kappa APEXII CCD diffractometer	1677 independent reflections
Radiation source: fine-focus sealed tube	1089 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.000
ω scans	θmax = 24.7°, θmin = 2.2°
Absorption correction: part of the refinement model (ΔF) (XABS2; Parkin et al., 1995)	h = −7→7
Tmin = 0.932, Tmax = 0.953	k = 0→22
1677 measured reflections	l = 0→10

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)] = 0.077	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.247	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.1389P)^2 + 0.421P] where P = (Fo^2 + 2Fc^2)/3
1677 reflections	(Δ/σ)max < 0.001
144 parameters	Δρmax = 0.36 e Å^−3
0 restraints	Δρmin = −0.55 e Å^−3

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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	Occ. (<1)
O1	0.0509 (5)	0.46898 (16)	0.2298 (3)	0.0808 (11)
N1	−0.1021 (5)	0.31127 (19)	0.1262 (4)	0.0706 (11)
C1	−0.0850 (8)	0.25000	0.0606 (6)	0.069 (2)
C2	−0.1511 (9)	0.3154 (3)	0.2862 (5)	0.0872 (17)
C3	−0.2709 (14)	0.25000	0.3206 (9)	0.106 (3)
C4	−0.0792 (7)	0.3771 (2)	0.0383 (5)	0.0817 (16)
C5	0.1016 (7)	0.4235 (2)	0.1168 (5)	0.0725 (16)
C6	0.3108 (8)	0.4325 (3)	0.1001 (6)	0.091 (2)
C7	0.4019 (9)	0.4871 (3)	0.2040 (6)	0.094 (2)
C8	0.2431 (9)	0.5075 (3)	0.2828 (5)	0.0852 (17)
C9	0.2247 (12)	0.5625 (3)	0.4039 (7)	0.120 (3)
P1	0.3506 (2)	0.25000	0.73427 (19)	0.0793 (7)
F1	0.3265 (10)	0.25000	0.5584 (6)	0.247 (6)
F2	0.0993 (9)	0.25000	0.7207 (8)	0.236 (6)
F3	0.3704 (10)	0.25000	0.9155 (7)	0.218 (5)
F4	0.6000 (9)	0.25000	0.7399 (8)	0.260 (7)
F5	0.449 (3)	0.3183 (5)	0.7947 (15)	0.204 (7)	0.500
F6	0.258 (3)	0.3213 (5)	0.699 (2)	0.260 (8)	0.500
H1	−0.05810	0.25000	−0.04260	0.0820*
H2A	−0.24330	0.35660	0.29500	0.1050*
H2B	−0.01270	0.32020	0.36270	0.1050*
H3A	−0.28490	0.25000	0.43150	0.1280*
H3B	−0.42050	0.25000	0.25680	0.1280*
H4A	−0.05180	0.36490	−0.06630	0.0980*
H4B	−0.21940	0.40290	0.02440	0.0980*
H6	0.38470	0.40730	0.03220	0.1090*
H7	0.54600	0.50550	0.21560	0.1130*
H9A	0.36010	0.58990	0.42480	0.1800*
H9B	0.20190	0.54010	0.50010	0.1800*
H9C	0.10040	0.59310	0.36490	0.1800*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0858 (19)	0.098 (2)	0.0648 (18)	0.0177 (16)	0.0303 (14)	0.0102 (15)
N1	0.070 (2)	0.094 (2)	0.0496 (19)	0.0089 (16)	0.0162 (14)	0.0031 (17)
C1	0.050 (3)	0.108 (5)	0.048 (3)	0.0000	0.008 (2)	0.0000
C2	0.104 (3)	0.107 (3)	0.057 (3)	0.013 (3)	0.032 (2)	0.000 (2)
C3	0.113 (5)	0.148 (7)	0.071 (4)	0.0000	0.052 (4)	0.0000
C4	0.085 (3)	0.102 (3)	0.058 (2)	0.027 (2)	0.013 (2)	0.014 (2)
C5	0.085 (3)	0.080 (3)	0.057 (2)	0.025 (2)	0.025 (2)	0.0179 (19)
C6	0.088 (3)	0.101 (4)	0.094 (4)	0.021 (2)	0.042 (3)	0.017 (3)
C7	0.087 (3)	0.102 (4)	0.098 (4)	−0.003 (3)	0.031 (3)	0.018 (3)
C8	0.105 (3)	0.086 (3)	0.067 (3)	0.005 (3)	0.022 (2)	0.020 (2)
C9	0.170 (6)	0.112 (4)	0.083 (4)	−0.004 (4)	0.039 (4)	0.000 (3)
P1	0.0552 (9)	0.1200 (15)	0.0645 (11)	0.0000	0.0157 (7)	0.0000
F1	0.104 (4)	0.578 (18)	0.065 (3)	0.0000	0.030 (3)	0.0000
F2	0.077 (3)	0.516 (17)	0.121 (5)	0.0000	0.036 (3)	0.0000
F3	0.111 (4)	0.449 (14)	0.094 (4)	0.0000	0.023 (3)	0.0000
F4	0.071 (3)	0.59 (2)	0.116 (5)	0.0000	0.012 (3)	0.0000
F5	0.291 (15)	0.108 (6)	0.199 (11)	−0.077 (8)	0.013 (10)	−0.036 (6)
F6	0.242 (13)	0.114 (7)	0.36 (2)	0.065 (7)	−0.111 (14)	0.018 (9)

Geometric parameters (Å, º)

P1—F6^i	1.469 (11)	C5—C6	1.317 (7)
P1—F1	1.488 (5)	C6—C7	1.407 (8)
P1—F2	1.510 (6)	C7—C8	1.334 (8)
P1—F3	1.536 (6)	C8—C9	1.487 (8)
P1—F4	1.508 (6)	C1—H1	0.9300
P1—F5	1.474 (11)	C2—H2B	0.9700
P1—F6	1.469 (11)	C2—H2A	0.9700
P1—F5^i	1.474 (11)	C3—H3A	0.9700
F5—F6	1.29 (2)	C3—H3B	0.9700
O1—C5	1.372 (5)	C4—H4A	0.9700
O1—C8	1.379 (6)	C4—H4B	0.9700
N1—C2	1.459 (6)	C6—H6	0.9300
N1—C4	1.474 (5)	C7—H7	0.9300
N1—C1	1.299 (4)	C9—H9C	0.9600
C2—C3	1.491 (7)	C9—H9A	0.9600
C4—C5	1.467 (6)	C9—H9B	0.9600
F4—P1—F5^i	69.5 (7)	N1—C4—C5	113.8 (3)
F4—P1—F6^i	110.6 (7)	O1—C5—C6	110.2 (4)
F5—P1—F6	52.1 (9)	C4—C5—C6	133.1 (4)
F5—P1—F5^i	122.0 (8)	O1—C5—C4	116.7 (4)
F5—P1—F6^i	171.5 (8)	C5—C6—C7	107.4 (5)
F5^i—P1—F6	171.5 (8)	C6—C7—C8	107.2 (5)
F6—P1—F6^i	132.9 (9)	O1—C8—C9	115.4 (5)
F5^i—P1—F6^i	52.1 (9)	O1—C8—C7	109.2 (4)
F2—P1—F5^i	111.4 (7)	C7—C8—C9	135.3 (6)
F2—P1—F6^i	69.0 (7)	N1^i—C1—H1	117.00
F3—P1—F4	94.5 (4)	N1—C1—H1	117.00
F3—P1—F5	72.2 (5)	N1—C2—H2A	110.00
F1—P1—F2	90.9 (4)	C3—C2—H2B	110.00
F1—P1—F3	178.9 (3)	N1—C2—H2B	110.00
F1—P1—F4	86.6 (4)	C3—C2—H2A	110.00
F1—P1—F5	108.3 (5)	H2A—C2—H2B	108.00
F1—P1—F6	80.2 (7)	C2^i—C3—H3A	109.00
F1—P1—F5^i	108.3 (5)	C2—C3—H3A	109.00
F1—P1—F6^i	80.2 (7)	C2—C3—H3B	109.00
F2—P1—F3	88.0 (4)	H3A—C3—H3B	108.00
F2—P1—F4	177.5 (4)	C2^i—C3—H3B	109.00
F2—P1—F5	111.4 (7)	N1—C4—H4B	109.00
F2—P1—F6	69.0 (7)	N1—C4—H4A	109.00
F4—P1—F5	69.5 (7)	H4A—C4—H4B	108.00
F4—P1—F6	110.6 (7)	C5—C4—H4A	109.00
F3—P1—F5^i	72.2 (5)	C5—C4—H4B	109.00
F3—P1—F6^i	99.4 (7)	C5—C6—H6	126.00
F3—P1—F6	99.4 (7)	C7—C6—H6	126.00
P1—F5—F6	63.7 (8)	C8—C7—H7	126.00
P1—F6—F5	64.2 (8)	C6—C7—H7	126.00
C5—O1—C8	105.9 (3)	H9B—C9—H9C	110.00
C1—N1—C2	120.1 (4)	C8—C9—H9A	109.00
C2—N1—C4	119.4 (4)	C8—C9—H9B	110.00
C1—N1—C4	120.5 (4)	C8—C9—H9C	109.00
N1—C1—N1^i	125.9 (4)	H9A—C9—H9B	109.00
N1—C2—C3	109.6 (4)	H9A—C9—H9C	109.00
C2—C3—C2^i	111.9 (6)
F5^i—P1—F5—F6	−172.5 (11)	C2—N1—C1—N1^i	−1.9 (7)
F1—P1—F6—F5	−122.5 (10)	C1—N1—C4—C5	−121.5 (4)
F2—P1—F6—F5	142.8 (11)	C4—N1—C1—N1^i	−180.0 (4)
F1—P1—F5—F6	61.1 (11)	C2—N1—C4—C5	60.4 (5)
F2—P1—F5—F6	−37.4 (11)	C1—N1—C2—C3	−25.1 (6)
F3—P1—F5—F6	−117.9 (11)	C4—N1—C2—C3	153.1 (5)
F4—P1—F5—F6	140.1 (11)	N1—C2—C3—C2^i	51.2 (7)
F3—P1—F6—F5	58.6 (10)	N1—C4—C5—C6	96.4 (6)
F4—P1—F6—F5	−39.9 (11)	N1—C4—C5—O1	−85.1 (4)
F6^i—P1—F6—F5	170.8 (12)	C4—C5—C6—C7	177.5 (5)
C5—O1—C8—C7	0.9 (5)	O1—C5—C6—C7	−1.1 (6)
C5—O1—C8—C9	178.1 (4)	C5—C6—C7—C8	1.7 (6)
C8—O1—C5—C4	−178.7 (4)	C6—C7—C8—C9	−178.0 (6)
C8—O1—C5—C6	0.2 (5)	C6—C7—C8—O1	−1.6 (6)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···F2^ii	0.93	2.40	3.312 (8)	167
C1—H1···F4^iii	0.93	2.52	3.044 (8)	116

Symmetry codes: (ii) x, y, z−1; (iii) x−1, y, z−1.