Tetra­butyl­ammonium bromo­trichloro­ferrate(III)

The Fe³⁺ centre in the complex anion of the title compound, [(C₄H₉)₄N][FeBrCl₃], is surrounded by three chloride anions and one bromide anion. The Br atom in [FeBrCl₃]^- is disordered, replacing Cl atoms. The Fe and N atoms lie on a twofold rotation axis.

Key indicators

• Single-crystal X-ray study
• T = 291 K
• Mean [sigma](C-C) = 0.006 Å
• Disorder in solvent or counterion
• R factor = 0.063
• wR factor = 0.164
• Data-to-parameter ratio = 18.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.04 Ratio
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors for        Fe1
PLAT302_ALERT_4_C Anion/Solvent Disorder .........................      44.00 Perc.

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

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

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Computing details

Data collection: CrysAlis CCD (UNIL IC & Kuma, 2000); cell refinement: CrysAlis RED (UNIL IC & Kuma, 2000); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL/PC (Sheldrick, 1990) and ORTEP-3 (Version 1.062; Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Tetrabutylammonium bromotrichloroferrate(III)

Crystal data

(C16H36N)[FeBrCl3]	F(000) = 1004
Mr = 484.57	Dx = 1.305 Mg m^−3
Orthorhombic, Pnna	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2a 2bc	Cell parameters from 4782 reflections
a = 18.5191 (11) Å	θ = 5–20°
b = 11.5864 (7) Å	µ = 2.55 mm^−1
c = 11.4957 (7) Å	T = 291 K
V = 2466.6 (3) Å^3	Prism, orange
Z = 4	0.35 × 0.27 × 0.14 mm

Data collection

Kuma KM-4-CCD diffractometer	2197 independent reflections
Radiation source: fine-focus sealed tube	1840 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.089
Detector resolution: 1048576 pixels mm^-1	θmax = 25.1°, θmin = 3.3°
ω scans	h = −22→21
Absorption correction: numerical (X-RED32; Stoe & Cie, 1999)	k = −13→10
Tmin = 0.476, Tmax = 0.711	l = −13→13
24549 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.164	H-atom parameters constrained
S = 1.27	w = 1/[σ^2(Fo^2) + (0.0766P)^2] where P = (Fo^2 + 2Fc^2)/3
2197 reflections	(Δ/σ)max = 0.001
121 parameters	Δρmax = 0.30 e Å^−3
0 restraints	Δρmin = −0.20 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	Occ. (<1)
Fe1	0.09291 (4)	0.2500	0.2500	0.0885 (4)
Cl1	0.1567 (5)	0.3881 (8)	0.1895 (7)	0.129 (3)	0.75
Cl2	0.0151 (3)	0.3010 (5)	0.3817 (5)	0.158 (2)	0.75
Br1	0.1658 (5)	0.3997 (8)	0.1763 (7)	0.0915 (11)	0.25
Br2	0.0379 (4)	0.3429 (5)	0.4072 (5)	0.1269 (15)	0.25
N2	0.4364 (2)	0.2500	0.2500	0.0600 (8)
C1	0.48270 (18)	0.3276 (3)	0.1730 (3)	0.0711 (9)
H1A	0.5058	0.2795	0.1149	0.085*
H1B	0.4509	0.3804	0.1323	0.085*
C2	0.5400 (2)	0.3972 (3)	0.2322 (3)	0.0895 (11)
H2A	0.5735	0.3463	0.2717	0.107*
H2B	0.5181	0.4475	0.2898	0.107*
C3	0.5805 (3)	0.4699 (5)	0.1415 (4)	0.1239 (17)
H3A	0.5977	0.4194	0.0802	0.149*
H3B	0.5471	0.5244	0.1069	0.149*
C4	0.6422 (3)	0.5338 (6)	0.1896 (5)	0.168 (3)
H4A	0.6263	0.6081	0.2163	0.252*
H4B	0.6782	0.5437	0.1304	0.252*
H4C	0.6624	0.4914	0.2536	0.252*
C5	0.39081 (18)	0.3258 (3)	0.3276 (3)	0.0691 (8)
H5A	0.4231	0.3738	0.3731	0.083*
H5B	0.3629	0.3769	0.2781	0.083*
C6	0.33950 (19)	0.2674 (3)	0.4101 (3)	0.0789 (9)
H6A	0.3072	0.2178	0.3664	0.095*
H6B	0.3667	0.2194	0.4635	0.095*
C7	0.2961 (3)	0.3526 (4)	0.4777 (4)	0.1119 (14)
H7A	0.3293	0.4033	0.5183	0.134*
H7B	0.2693	0.3997	0.4229	0.134*
C8	0.2444 (3)	0.3059 (5)	0.5639 (4)	0.1279 (16)
H8A	0.2126	0.2520	0.5264	0.192*
H8B	0.2165	0.3680	0.5964	0.192*
H8C	0.2704	0.2675	0.6249	0.192*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0952 (6)	0.0947 (7)	0.0756 (5)	0.000	0.000	0.0136 (4)
Cl1	0.159 (5)	0.071 (2)	0.158 (5)	−0.0188 (19)	0.045 (2)	−0.0057 (19)
Cl2	0.167 (4)	0.180 (4)	0.128 (3)	0.048 (3)	0.068 (2)	0.038 (3)
Br1	0.1035 (18)	0.067 (3)	0.1040 (18)	−0.0065 (19)	0.0227 (19)	−0.0065 (17)
Br2	0.171 (4)	0.116 (3)	0.093 (2)	0.029 (2)	0.046 (2)	0.0300 (18)
N2	0.080 (2)	0.049 (2)	0.0514 (17)	0.000	0.000	0.0014 (15)
C1	0.084 (2)	0.066 (2)	0.0634 (17)	−0.0059 (17)	0.0043 (15)	0.0052 (15)
C2	0.095 (2)	0.082 (3)	0.092 (2)	−0.018 (2)	−0.004 (2)	0.0117 (19)
C3	0.115 (3)	0.132 (4)	0.124 (3)	−0.045 (3)	−0.014 (3)	0.023 (3)
C4	0.128 (4)	0.188 (6)	0.188 (6)	−0.072 (4)	−0.030 (4)	0.055 (5)
C5	0.090 (2)	0.056 (2)	0.0618 (16)	0.0050 (16)	−0.0020 (15)	−0.0047 (14)
C6	0.086 (2)	0.075 (2)	0.076 (2)	0.0037 (17)	0.0095 (17)	−0.0011 (17)
C7	0.128 (3)	0.118 (3)	0.090 (3)	0.032 (3)	0.028 (3)	−0.011 (2)
C8	0.126 (3)	0.154 (4)	0.104 (3)	0.019 (3)	0.035 (3)	−0.020 (3)

Geometric parameters (Å, º)

Fe1—Cl1	2.107 (10)	C4—H4A	0.9600
Fe1—Cl2	2.172 (6)	C4—H4B	0.9600
Fe1—Br2	2.337 (6)	C4—H4C	0.9600
Fe1—Br1	2.356 (12)	C5—C6	1.504 (4)
N2—C5	1.509 (4)	C5—H5A	0.9700
N2—C1	1.525 (4)	C5—H5B	0.9700
C1—C2	1.497 (5)	C6—C7	1.492 (5)
C1—H1A	0.9700	C6—H6A	0.9700
C1—H1B	0.9700	C6—H6B	0.9700
C2—C3	1.536 (6)	C7—C8	1.480 (6)
C2—H2A	0.9700	C7—H7A	0.9700
C2—H2B	0.9700	C7—H7B	0.9700
C3—C4	1.469 (6)	C8—H8A	0.9600
C3—H3A	0.9700	C8—H8B	0.9600
C3—H3B	0.9700	C8—H8C	0.9600
Cl1—Fe1—Cl1^i	111.8 (4)	C2—C3—H3A	108.8
Cl1—Fe1—Cl2^i	110.4 (3)	C4—C3—H3B	108.8
Cl1—Fe1—Cl2	113.3 (2)	C2—C3—H3B	108.8
Cl2^i—Fe1—Cl2	96.9 (3)	H3A—C3—H3B	107.7
Cl1—Fe1—Br2^i	109.8 (3)	C3—C4—H4A	109.5
Cl1—Fe1—Br2	98.6 (2)	C3—C4—H4B	109.5
Cl2^i—Fe1—Br2	112.06 (16)	H4A—C4—H4B	109.5
Cl2—Fe1—Br2	17.6 (2)	C3—C4—H4C	109.5
Br2^i—Fe1—Br2	128.4 (3)	H4A—C4—H4C	109.5
Cl1—Fe1—Br1	2.3 (4)	H4B—C4—H4C	109.5
Cl1^i—Fe1—Br1	110.86 (8)	C6—C5—N2	117.7 (3)
Cl2^i—Fe1—Br1	109.3 (2)	C6—C5—H5A	107.9
Cl2—Fe1—Br1	115.5 (2)	N2—C5—H5A	107.9
Br2^i—Fe1—Br1	108.1 (2)	C6—C5—H5B	107.9
Br2—Fe1—Br1	100.9 (2)	N2—C5—H5B	107.9
Br1—Fe1—Br1^i	110.0 (3)	H5A—C5—H5B	107.2
C5^i—N2—C5	112.0 (3)	C7—C6—C5	111.9 (3)
C5^i—N2—C1	108.34 (16)	C7—C6—H6A	109.2
C5—N2—C1	108.31 (17)	C5—C6—H6A	109.2
C1^i—N2—C1	111.6 (3)	C7—C6—H6B	109.2
C2—C1—N2	116.9 (3)	C5—C6—H6B	109.2
C2—C1—H1A	108.1	H6A—C6—H6B	107.9
N2—C1—H1A	108.1	C8—C7—C6	117.1 (4)
C2—C1—H1B	108.1	C8—C7—H7A	108.0
N2—C1—H1B	108.1	C6—C7—H7A	108.0
H1A—C1—H1B	107.3	C8—C7—H7B	108.0
C1—C2—C3	109.5 (3)	C6—C7—H7B	108.0
C1—C2—H2A	109.8	H7A—C7—H7B	107.3
C3—C2—H2A	109.8	C7—C8—H8A	109.5
C1—C2—H2B	109.8	C7—C8—H8B	109.5
C3—C2—H2B	109.8	H8A—C8—H8B	109.5
H2A—C2—H2B	108.2	C7—C8—H8C	109.5
C4—C3—C2	113.6 (4)	H8A—C8—H8C	109.5
C4—C3—H3A	108.8	H8B—C8—H8C	109.5

Symmetry code: (i) x, −y+1/2, −z+1/2.