Diisopropyl­ammonium perchlorate at 263 K

Diisopropyl­ammonium perchlorate, C₆H₁₆N⁺·ClO₄^-, crystallizes in the monoclinic space group P2₁/c in the temperature range from 213 to 291 K. The asymmetric unit contains two diisopropyl­ammonium cations and two perchlorate anions in general positions. Each cation acts as double hydrogen-bond donor and one O atom of each perchlorate anion accepts two hydrogen bonds from chains that are classified as C(4).

Key indicators

• Single-crystal X-ray study
• T = 263 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.044
• wR factor = 0.090
• Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT242_ALERT_2_A Check Low       Ueq as Compared to Neighbors for        Cl2

Author Response: All the methyl groups of both diisopropylammonium cations show significant larger U values in contrast to the carbon atoms of the CH groups they are attached to. For the general view of the structure this seemed plausible to us.

Alert level B
PLAT026_ALERT_3_B Ratio Observed / Unique Reflections too Low ....         39 Perc.
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        Cl1

Author Response: All the methyl groups of both diisopropylammonium cations show significant larger U values in contrast to the carbon atoms of the CH groups they are attached to. For the general view of the structure this seemed plausible to us.

Alert level C
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C11

Author Response: All the methyl groups of both diisopropylammonium cations show significant larger U values in contrast to the carbon atoms of the CH groups they are attached to. For the general view of the structure this seemed plausible to us.

PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C21

Author Response: All the methyl groups of both diisopropylammonium cations show significant larger U values in contrast to the carbon atoms of the CH groups they are attached to. For the general view of the structure this seemed plausible to us.

PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C24

Author Response: All the methyl groups of both diisopropylammonium cations show significant larger U values in contrast to the carbon atoms of the CH groups they are attached to. For the general view of the structure this seemed plausible to us.

PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5
PLAT430_ALERT_2_C Short Inter D...A Contact  O11    ..  O12     ..       2.88 Ang.
PLAT430_ALERT_2_C Short Inter D...A Contact  O21    ..  O24     ..       2.88 Ang.

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         24

   1 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   7 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
   7 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

---

S1. Comment

In recent years a series of diisopropylammonium (dip) salts were synthesized and structurally characterized. Their structures are dominated by hydrogen-bonding patterns. These pattern can be classified as quasi molecular (dip₂[SiF₆]) (Rei\&s, 1998), one dimensional polymeric (dipHF₂, dipCl, dipBr, dipI, dipNO₃) (Rei\&s, 2001; Rei\&s & Koppelhuber-Bitschnau, 2002), two dimensional networks (dip₂[SO₄]) (Rei\&s, 2000) and three dimensional networks (dip[IrCl₆]₂) (Rei\&s, 2004). This class of compounds is an ideal model system for the investigation of anion-dependent formation of one- or higher-dimensional hydrogen-bonded polymers. Here we present a further example of a dip salt that shows a chain- type structure for an intermediate phase.

The asymmetric unit of the the title compound, (I), consists of two perchlorate anions and two diisopropylammonium cations, both located in general positions (Fig. 1). The C—C and N—C bond lengths in the cation are as expected, and both perchlorate anions show almost tetrahedral geometry (Table 1). One oxygen atom of each perchlorate anion (O11 and O21) accepts two hydrogen bonds from neighbouring ammonium groups, while each NH₂ group donates two hydrogen bonds. In the asymmetric unit, two crystallographically independent chains are found with very similar geometries. According to Etter's nomenclature, both chains can be classified as C(4). Fig. 2 illustrates the packing of the compound along the b axis. Chains are stacked to form the well known herring-bone motif (Blume et al., 2000; Kitaigorodski, 1961; Rei\&s, 2002).

Thermal analysis (heating rate of 5°C/min) and temperature-dependent powder diffraction of the title compound in the temperature range from -150°C to +20°C reveal two first-order phase transformations at -60°C and +18°C. In addition to crystals of (I) (the phase stable from -60°C to 18°C), crystals were also obtained at room temperature forming extremely weak diffracting platelets were always non-merohedrally twinned. A partial dataset adequate to solve the structure (after discarding all overlapping reflections) was collected but the structure could not be refined in detail. Nevertheless, it can be concluded that this phase is composed of quasi-molecular ring-shaped, dimeric dip₂[ClO₄]₂ units. The space group P1 [a = 8.180 (5) Å, b = 8.530 (5) Å, c = 8.730 (5) Å, α = 83.040 (5)°, β = 64.837 (5)°, γ = 80.078 (5) Å] is a plausible choice as no center of symmetry is present in the dip₂[ClO₄] dimer and no higher metrical symmetry of the lattice is found.

Related literature

For related literature, see: Blume et al. (2000); Etter et al. (1990); Kitaigorodski (1961); Rei\&s (1998, 2000, 2001); Rei\&s & Engel (2004); Rei\&s & Koppelhuber-Bitschnau (2002).

S2. Experimental

At room temperature, 14.3 mmol diisopropylamine were added to (70 percent) perchloric acid (2.5 ml, 38.5 mmol) producing a colourless solution. From this solution, small thin platelets were obtained within a few days at room temperature. The crystals were investigated under ambient conditions. At -20°C, colourless needles grew from the solution in a few days. One crystal was mounted on a Stoe image plate diffractometer while keeping the temperature below the transition temperature of + 18°C. Cooling the crystals below -60°C resulted in twinning as revealed by split reflection profiles.

S3. Refinement

All H atoms were located in successive Fourier synthesis. In the final stages of refinement, all H atoms of the CH₃ and CH groups were refined using a riding model with U_iso set to 1.5 and 1.2 times U_eq of the corresponding C atoms. The four H atoms of the two ammonium groups were refined freely with their U_iso set at 1.2 times U_eq of the N atoms. As a consequence of the low intensity, correlations appear for some displacement parameters. These effects were reduced by introducing anti-bump restraints for N1, C11, N2 and C24.

Computing details

Data collection: IPDS (Stoe & Cie, 2000); cell refinement: IPDS; data reduction: IPDS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The asymmetric unit of the title compound (displacement ellipsoids at the 40% probability level, H atoms drawn with arbitrary radius).
	Fig. 2. Crystal packing seen along the b direction.

Diisopropylammonium perchlorate

Crystal data

C6H16N^+·ClO4^−	F(000) = 864
Mr = 201.65	Dx = 1.275 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 17.7018 (18) Å	Cell parameters from 7606 reflections
b = 8.2468 (7) Å	θ = 4.2–25.0°
c = 16.0601 (16) Å	µ = 0.35 mm^−1
β = 116.334 (11)°	T = 263 K
V = 2101.2 (3) Å^3	Needle, colourless
Z = 8	0.3 × 0.15 × 0.15 mm

Data collection

Stoe IPDS diffractometer	1435 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.055
Graphite monochromator	θmax = 25.0°, θmin = 4.2°
Detector resolution: 50 pixels mm^-1	h = −21→21
ω scans	k = −9→9
26389 measured reflections	l = −19→19
3673 independent 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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.090	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ^2(Fo^2) + (0.026P)^2] where P = (Fo^2 + 2Fc^2)/3
3673 reflections	(Δ/σ)max < 0.001
229 parameters	Δρmax = 0.34 e Å^−3
24 restraints	Δρmin = −0.19 e Å^−3

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
Cl2	0.60921 (5)	0.20439 (13)	0.26584 (7)	0.0772 (3)
O21	0.57452 (19)	0.0819 (4)	0.2987 (3)	0.1385 (13)
O22	0.68890 (17)	0.2498 (4)	0.3304 (2)	0.1210 (10)
O23	0.6161 (2)	0.1435 (5)	0.1871 (2)	0.1564 (14)
O24	0.55388 (16)	0.3388 (3)	0.2396 (2)	0.1166 (11)
Cl1	0.10780 (5)	0.28299 (12)	0.34991 (6)	0.0651 (3)
O11	0.07405 (15)	0.4100 (3)	0.28279 (17)	0.0988 (9)
O12	0.05430 (15)	0.1454 (3)	0.31697 (19)	0.1012 (9)
O13	0.11082 (16)	0.3366 (4)	0.43558 (18)	0.1087 (9)
O14	0.19014 (15)	0.2426 (3)	0.36572 (19)	0.0996 (8)
N1	0.09458 (16)	0.7607 (4)	0.36280 (19)	0.0585 (8)
H1A	0.0584 (19)	0.824 (4)	0.329 (2)	0.070*
H1B	0.0812 (19)	0.665 (4)	0.338 (2)	0.070*
C11	0.0929 (2)	0.7492 (4)	0.4552 (2)	0.0667 (9)
H11	0.1313	0.6622	0.4910	0.080*
C12	0.0049 (2)	0.7030 (5)	0.4375 (3)	0.1037 (13)
H12A	−0.0114	0.6055	0.4012	0.145*
H12B	−0.0333	0.7889	0.4044	0.145*
H12C	0.0032	0.6852	0.4958	0.145*
C13	0.1219 (3)	0.9042 (5)	0.5087 (2)	0.0944 (12)
H13A	0.1778	0.9291	0.5172	0.132*
H13B	0.1220	0.8922	0.5683	0.132*
H13C	0.0844	0.9904	0.4750	0.132*
C14	0.17520 (18)	0.8031 (4)	0.3579 (2)	0.0646 (9)
H14	0.1918	0.9127	0.3831	0.078*
C15	0.1570 (2)	0.8060 (5)	0.2562 (2)	0.0911 (12)
H15A	0.1167	0.8897	0.2246	0.127*
H15B	0.1345	0.7030	0.2284	0.127*
H15C	0.2082	0.8269	0.2513	0.127*
C16	0.2454 (2)	0.6886 (5)	0.4154 (3)	0.0871 (12)
H16A	0.2541	0.6916	0.4788	0.122*
H16B	0.2963	0.7207	0.4124	0.122*
H16C	0.2306	0.5804	0.3916	0.122*
N2	0.40327 (16)	0.2296 (4)	0.27392 (19)	0.0630 (8)
H2A	0.4432 (19)	0.167 (4)	0.276 (2)	0.076*
H2B	0.418 (2)	0.319 (4)	0.264 (2)	0.076*
C21	0.32467 (18)	0.1813 (4)	0.1909 (2)	0.0699 (10)
H21	0.3116	0.0693	0.2004	0.084*
C22	0.2512 (2)	0.2844 (5)	0.1790 (3)	0.1014 (13)
H22A	0.2428	0.2783	0.2340	0.142*
H22B	0.2015	0.2464	0.1266	0.142*
H22C	0.2620	0.3948	0.1686	0.142*
C23	0.3428 (2)	0.1828 (5)	0.1076 (2)	0.0957 (13)
H23A	0.3920	0.1186	0.1205	0.134*
H23B	0.3524	0.2923	0.0943	0.134*
H23C	0.2955	0.1385	0.0549	0.134*
C24	0.4043 (2)	0.2392 (4)	0.3673 (2)	0.0736 (10)
H24	0.3630	0.3208	0.3644	0.088*
C25	0.4913 (3)	0.2970 (6)	0.4363 (2)	0.1139 (14)
H25A	0.5042	0.3970	0.4148	0.159*
H25B	0.5325	0.2167	0.4418	0.159*
H25C	0.4920	0.3139	0.4958	0.159*
C26	0.3802 (2)	0.0803 (5)	0.3943 (3)	0.0959 (12)
H26A	0.3231	0.0546	0.3520	0.134*
H26B	0.3853	0.0881	0.4562	0.134*
H26C	0.4170	−0.0034	0.3921	0.134*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl2	0.0682 (6)	0.0601 (7)	0.1082 (7)	−0.0049 (5)	0.0436 (6)	−0.0054 (6)
O21	0.131 (2)	0.077 (2)	0.256 (4)	0.0094 (17)	0.130 (3)	0.044 (2)
O22	0.0790 (16)	0.117 (3)	0.129 (2)	−0.0064 (16)	0.0116 (16)	−0.001 (2)
O23	0.198 (4)	0.146 (3)	0.141 (3)	0.005 (2)	0.089 (3)	−0.046 (2)
O24	0.0857 (18)	0.070 (2)	0.195 (3)	0.0166 (15)	0.0628 (19)	0.0217 (18)
Cl1	0.0609 (5)	0.0534 (6)	0.0699 (6)	0.0020 (5)	0.0190 (4)	0.0013 (5)
O11	0.0980 (18)	0.0623 (19)	0.0930 (19)	0.0013 (14)	0.0033 (14)	0.0214 (15)
O12	0.0899 (18)	0.0562 (18)	0.110 (2)	−0.0123 (14)	0.0010 (15)	0.0083 (14)
O13	0.133 (2)	0.114 (3)	0.093 (2)	0.0004 (16)	0.0633 (18)	−0.0212 (17)
O14	0.0694 (14)	0.102 (2)	0.126 (2)	0.0190 (14)	0.0431 (14)	0.0024 (17)
N1	0.0544 (16)	0.059 (2)	0.0609 (17)	0.0007 (13)	0.0249 (13)	−0.0054 (14)
C11	0.087 (2)	0.065 (3)	0.0551 (19)	0.0092 (17)	0.0378 (17)	0.0068 (16)
C12	0.117 (3)	0.109 (3)	0.121 (3)	−0.010 (2)	0.087 (3)	−0.004 (3)
C13	0.129 (3)	0.089 (3)	0.065 (2)	0.003 (2)	0.042 (2)	−0.013 (2)
C14	0.0551 (19)	0.060 (2)	0.081 (2)	−0.0053 (17)	0.0320 (17)	−0.0027 (19)
C15	0.087 (3)	0.115 (4)	0.088 (3)	0.002 (2)	0.054 (2)	0.002 (3)
C16	0.064 (2)	0.082 (3)	0.112 (3)	0.009 (2)	0.036 (2)	0.004 (2)
N2	0.0567 (16)	0.066 (2)	0.0618 (15)	0.0019 (15)	0.0226 (13)	0.0093 (16)
C21	0.054 (2)	0.069 (3)	0.071 (2)	0.0000 (17)	0.0140 (18)	0.0006 (19)
C22	0.066 (2)	0.132 (4)	0.092 (3)	0.020 (2)	0.023 (2)	0.025 (3)
C23	0.095 (3)	0.110 (4)	0.070 (2)	−0.002 (2)	0.026 (2)	−0.004 (2)
C24	0.087 (2)	0.078 (3)	0.059 (2)	0.0179 (18)	0.0353 (17)	0.0066 (19)
C25	0.134 (3)	0.115 (4)	0.063 (2)	−0.016 (3)	0.017 (2)	−0.009 (2)
C26	0.123 (3)	0.094 (3)	0.084 (3)	0.006 (2)	0.058 (2)	0.018 (2)

Geometric parameters (Å, º)

Cl2—O22	1.381 (3)	C15—H15C	0.9600
Cl2—O21	1.402 (3)	C16—H16A	0.9600
Cl2—O24	1.414 (3)	C16—H16B	0.9600
Cl2—O23	1.416 (3)	C16—H16C	0.9600
Cl1—O14	1.404 (2)	N2—C21	1.492 (4)
Cl1—O12	1.421 (2)	N2—C24	1.493 (4)
Cl1—O13	1.423 (3)	N2—H2A	0.86 (3)
Cl1—O11	1.430 (2)	N2—H2B	0.82 (3)
N1—C11	1.500 (4)	C21—C22	1.494 (5)
N1—C14	1.505 (4)	C21—C23	1.509 (5)
N1—H1A	0.82 (3)	C21—H21	0.9800
N1—H1B	0.86 (3)	C22—H22A	0.9600
C11—C13	1.499 (5)	C22—H22B	0.9600
C11—C12	1.504 (5)	C22—H22C	0.9600
C11—H11	0.9800	C23—H23A	0.9600
C12—H12A	0.9600	C23—H23B	0.9600
C12—H12B	0.9600	C23—H23C	0.9600
C12—H12C	0.9600	C24—C26	1.500 (5)
C13—H13A	0.9600	C24—C25	1.521 (5)
C13—H13B	0.9600	C24—H24	0.9800
C13—H13C	0.9600	C25—H25A	0.9600
C14—C16	1.507 (4)	C25—H25B	0.9600
C14—C15	1.518 (4)	C25—H25C	0.9600
C14—H14	0.9800	C26—H26A	0.9600
C15—H15A	0.9600	C26—H26B	0.9600
C15—H15B	0.9600	C26—H26C	0.9600
O22—Cl2—O21	112.6 (2)	C14—C16—H16A	109.5
O22—Cl2—O24	110.68 (19)	C14—C16—H16B	109.5
O21—Cl2—O24	108.44 (17)	H16A—C16—H16B	109.5
O22—Cl2—O23	107.6 (2)	C14—C16—H16C	109.5
O21—Cl2—O23	107.9 (2)	H16A—C16—H16C	109.5
O24—Cl2—O23	109.5 (2)	H16B—C16—H16C	109.5
O14—Cl1—O12	110.17 (17)	C21—N2—C24	120.2 (3)
O14—Cl1—O13	107.94 (16)	C21—N2—H2A	107 (2)
O12—Cl1—O13	109.93 (18)	C24—N2—H2A	111 (2)
O14—Cl1—O11	111.29 (16)	C21—N2—H2B	108 (2)
O12—Cl1—O11	108.52 (15)	C24—N2—H2B	107 (3)
O13—Cl1—O11	108.97 (18)	H2A—N2—H2B	103 (3)
C11—N1—C14	120.1 (2)	C22—C21—N2	112.1 (3)
C11—N1—H1A	110 (2)	C22—C21—C23	113.4 (3)
C14—N1—H1A	107 (2)	N2—C21—C23	108.0 (3)
C11—N1—H1B	106 (2)	C22—C21—H21	107.7
C14—N1—H1B	105 (2)	N2—C21—H21	107.7
H1A—N1—H1B	108 (3)	C23—C21—H21	107.7
C13—C11—N1	111.2 (3)	C21—C22—H22A	109.5
C13—C11—C12	112.7 (3)	C21—C22—H22B	109.5
N1—C11—C12	107.7 (3)	H22A—C22—H22B	109.5
C13—C11—H11	108.4	C21—C22—H22C	109.5
N1—C11—H11	108.4	H22A—C22—H22C	109.5
C12—C11—H11	108.4	H22B—C22—H22C	109.5
C11—C12—H12A	109.5	C21—C23—H23A	109.5
C11—C12—H12B	109.5	C21—C23—H23B	109.5
H12A—C12—H12B	109.5	H23A—C23—H23B	109.5
C11—C12—H12C	109.5	C21—C23—H23C	109.5
H12A—C12—H12C	109.5	H23A—C23—H23C	109.5
H12B—C12—H12C	109.5	H23B—C23—H23C	109.5
C11—C13—H13A	109.5	N2—C24—C26	111.5 (3)
C11—C13—H13B	109.5	N2—C24—C25	107.8 (3)
H13A—C13—H13B	109.5	C26—C24—C25	112.9 (3)
C11—C13—H13C	109.5	N2—C24—H24	108.2
H13A—C13—H13C	109.5	C26—C24—H24	108.2
H13B—C13—H13C	109.5	C25—C24—H24	108.2
N1—C14—C16	111.5 (3)	C24—C25—H25A	109.5
N1—C14—C15	107.8 (3)	C24—C25—H25B	109.5
C16—C14—C15	113.1 (3)	H25A—C25—H25B	109.5
N1—C14—H14	108.1	C24—C25—H25C	109.5
C16—C14—H14	108.1	H25A—C25—H25C	109.5
C15—C14—H14	108.1	H25B—C25—H25C	109.5
C14—C15—H15A	109.5	C24—C26—H26A	109.5
C14—C15—H15B	109.5	C24—C26—H26B	109.5
H15A—C15—H15B	109.5	H26A—C26—H26B	109.5
C14—C15—H15C	109.5	C24—C26—H26C	109.5
H15A—C15—H15C	109.5	H26A—C26—H26C	109.5
H15B—C15—H15C	109.5	H26B—C26—H26C	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O11^i	0.82 (3)	2.34 (3)	3.115 (4)	157 (3)
N1—H1B···O11	0.86 (3)	2.27 (3)	3.119 (4)	169 (3)
N2—H2A···O21	0.86 (3)	2.30 (3)	3.124 (4)	160 (3)
N2—H2B···O21^ii	0.82 (3)	2.42 (3)	3.219 (4)	166 (3)

Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x+1, y+1/2, −z+1/2.