catena-Poly[[(tetra­hydro­furan-κO)potas­sium]-di-μ-dimethyl­amido-κ4N:N-aluminium-di-μ-dimethyl­amido-κ4N:N-potassium-di-μ-dimethyl­amido-κ4N:N-aluminium-di-μ-dimethyl­amido-κ4N:N]

Purdy, A.; Parrish, D.

doi:10.1107/S1600536813003553

metal-organic compounds

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ISSN: 2056-9890

Volume 69| Part 3| March 2013| Page m147

doi:10.1107/S1600536813003553

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catena-Poly[[(tetrahydrofuran-κO)potassium]-di-μ-dimethylamido-κ⁴N:N-aluminium-di-μ-dimethylamido-κ⁴N:N-potassium-di-μ-dimethylamido-κ⁴N:N-aluminium-di-μ-dimethylamido-κ⁴N:N]

Andrew Purdy ^a ^*‡ and Damon Parrish ^a §

^aNaval Research Laboratory, 4555 Overlook Av, SW, Washington, DC 20375, USA
^*Correspondence e-mail: andrew.purdy@nrl.navy.mil

(Received 24 November 2012; accepted 4 February 2013; online 13 February 2013)

The title compound, [Al₂K₂(C₂H₆N)₈(C₄H₈O)]_n, formed during the sonochemical reaction between Al(NMe₂)₃ and sodium–potassium alloy in the presence of tetrahydrofuran (THF). Its asymmetric unit has two inequivalent K⁺ sites. One site is coordinated by a THF ligand, and crystallizes as a one-dimensional polymer with a backbone of catenated AlN₂K rings. A twofold rotation axis bisects one K⁺ site and the THF ligand; the second K⁺ site is situated on an inversion centre, resulting in a planar four-coordination by N atoms. The latter symmetry operation generates the second half of the THF molecule and fills out the coordination sphere of the potassium sites. The chains extend along the c-axis direction and zigzag at the THF-coordinated K⁺ sites by an angle of 106.02 (5)°.

Related literature

Several (RR′N)₄AlM (M = Li, Na) compounds that have catenated AlN₂M chains have been reported previously (Eisler & Chivers, 2006 ); Rings et al. 2000 ). The structure of tris(dimethylamino)aluminium is a molecular dimer, see: Ouzounis et al. (1983 ). Heavily solvated tetraaminoalanates tend to have separated cations instead of catenated chain structures, see: Hensen et al. (1999 ). For details of the synthesis, see: Ruff (1960 ); Ouzounis et al. (1983).

Experimental

Crystal data

[Al₂K₂(C₂H₆N)₈(C₄H₈O)]
M_r = 278.44
Monoclinic, C 2/c
a = 13.247 (4) Å
b = 12.075 (4) Å
c = 20.822 (7) Å
β = 90.979 (5)°
V = 3330.1 (19) Å³
Z = 8
Mo Kα radiation
μ = 0.36 mm⁻¹
T = 173 K
0.74 × 0.57 × 0.42 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ) T_min = 0.776, T_max = 0.863
18795 measured reflections
4928 independent reflections
3986 reflections with I > 2σ(I)
R_int = 0.023

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.107
S = 1.03
4928 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536813003553/nk2195sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813003553/nk2195Isup2.hkl

checkCIF report

Comment top

The title compound consists of an alternating chain of aluminium and potassium ions linked by bridging N atoms into a series of catenated 4-membered rings. One potassium site, K2, is 4-coordinate and planar, whereas a tetrahydrofuran (THF) ligand gives K1 a 5-coordinate twisted geometry. The chain extends along c and zigzags along b by an angle of 106.02° at each K1 atom. All N—Al—N angles are within 3° of the tetrahedral angle, and the Al—N distances of 1.838 (1) - 1.855 (1) Å are within the normal range for covalent Al—N bonds (Hensen, et al., 1999). Similar one-dimensional polymeric chain structures have been observed in the Li and Na tetraamidoaluminates MAl(NH(CHMe₂)₄)₄ (M= Li or Na), and Na(THF)Al(NHp-Tol)₄ (Eisler and Chivers, 2006). An alkali amidoaluminate with less sterically demanding ligands, LiAl(NHMe)₄ (Rings, et al. 2000), is coordinated in a three-dimensional polymeric framework. Amidoaluminates with fully solvated alkali cations tend to have isolated ions instead (Hensen, et al., 1999).

Related literature top

Several (RR'N)₄AlM (M = Li, Na) compounds that have catenated AlN₂M chains have been reported previously (Eisler & Chivers, 2006; Rings et al. 2000). The structure of tris(dimethylamino)aluminium is a molecular dimer, see: Ouzounis et al. (1983). Heavily solvated tetraaminoalanates tend to have separated cations instead of catenated chain structures, see: Hensen et al. (1999). For details of the synthesis, see: Ruff (1960); Ouzounis et al. (1983).

Experimental top

All manipulations were performed in an a drybox under argon with dry solvents or inside a closed bulb. Tris(dimethylamino)aluminium (Ruff, 1960) was prepared by slowly adding LiNMe₂ (6.07 g, 0.119 mmol) to a solution of AlCl₃ (5.24 g, 0.039 mmol) in 50 ml Et₂O. After the exotherm was over, the reaction was sonicated for 3 h in a closed bulb and then all solvents were removed under vacuum. The solids were sublimed under dynamic vacuum at 70–90 °C for 12 h, affording 5.51 g A l(NMe₂)₃ (88%) on the cold finger. The ¹H NMR matched reported literature (Ouzounis, et al., 1983).

In an attempt to prepare aluminium nanoparticles a mixture of 1 g A l(NMe₂)₃ and 0.55 g Na/K (50:50 by wt) in 25 ml of toluene was sonicated for 1 day. Al-27 NMR showed no evidence for aluminium metal. About 5 ml THF was added and the mixture was sonicated for several more days. After filtration in the drybox, the orange-brown solution was allowed to slowly evaporate in a vial. Crystals of the title compound slowly formed.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP diagram of the asymmetric unit, expanded to show the complete THF ligand. Symmetry code: A, -x+1, y, -z+3/2. Ellipsoids are at the 50& probability level.
	Fig. 2. Packing diagram illustrating the 1-D polymeric chains.

catena-Poly[[(tetrahydrofuran-κO)potassium]-di-µ-dimethylamido-κ⁴N:N-aluminium-di-µ-dimethylamido-κ⁴N:N-potassium-di-µ-dimethylamido-κ⁴N:N-aluminium-di-µ-dimethylamido-κ⁴N:N] top

Crystal data top

[Al₂K₂(C₂H₆N)₈(C₄H₈O)]	F(000) = 1216
M_r = 556.88	D_x = 1.111 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.247 (4) Å	Cell parameters from 6485 reflections
b = 12.075 (4) Å	θ = 2.3–30.2°
c = 20.822 (7) Å	µ = 0.36 mm⁻¹
β = 90.979 (5)°	T = 173 K
V = 3330.1 (19) Å³	Chunk, orange
Z = 4	0.74 × 0.57 × 0.42 mm

Data collection top

Bruker SMART APEXII CCD diffractometer	4928 independent reflections
Radiation source: fine-focus sealed tube	3986 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
ω scans	θ_max = 30.9°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −18→18
T_min = 0.776, T_max = 0.863	k = −15→17
18795 measured reflections	l = −29→29

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.107	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0567P)² + 0.9926P] where P = (F_o² + 2F_c²)/3
4928 reflections	(Δ/σ)_max = 0.001
155 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.30 e Å⁻³

Crystal data top

[Al₂K₂(C₂H₆N)₈(C₄H₈O)]	V = 3330.1 (19) Å³
M_r = 556.88	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 13.247 (4) Å	µ = 0.36 mm⁻¹
b = 12.075 (4) Å	T = 173 K
c = 20.822 (7) Å	0.74 × 0.57 × 0.42 mm
β = 90.979 (5)°

Data collection top

Bruker SMART APEXII CCD diffractometer	4928 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2008)	3986 reflections with I > 2σ(I)
T_min = 0.776, T_max = 0.863	R_int = 0.023
18795 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	0 restraints
wR(F²) = 0.107	H-atom parameters constrained
S = 1.03	Δρ_max = 0.25 e Å⁻³
4928 reflections	Δρ_min = −0.30 e Å⁻³
155 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
K1	0.5000	0.32471 (3)	0.7500	0.03918 (11)
K2	0.5000	0.0000	0.5000	0.07103 (19)
Al	0.52871 (2)	0.22259 (3)	0.595808 (16)	0.02748 (9)
O1S	0.5000	0.54941 (12)	0.7500	0.0520 (3)
N1	0.50523 (8)	0.23469 (9)	0.50846 (5)	0.0361 (2)
N2	0.60258 (8)	0.34150 (9)	0.62545 (5)	0.0374 (2)
N3	0.59582 (7)	0.09033 (8)	0.61187 (5)	0.0338 (2)
N4	0.40721 (7)	0.21492 (9)	0.63840 (5)	0.0358 (2)
C1S	0.57959 (13)	0.61739 (15)	0.77418 (9)	0.0614 (4)
H1SA	0.6445	0.5961	0.7547	0.074*
H1SB	0.5862	0.6096	0.8214	0.074*
C2S	0.55312 (18)	0.73207 (19)	0.75688 (16)	0.1055 (10)
H2SA	0.5692	0.7829	0.7929	0.127*
H2SB	0.5910	0.7561	0.7188	0.127*
C11	0.40625 (11)	0.24265 (14)	0.47861 (7)	0.0497 (3)
H11A	0.4061	0.2036	0.4374	0.075*
H11B	0.3893	0.3207	0.4715	0.075*
H11C	0.3562	0.2090	0.5067	0.075*
C12	0.58075 (12)	0.27839 (15)	0.46587 (7)	0.0543 (4)
H12A	0.5837	0.2323	0.4272	0.081*
H12B	0.6468	0.2781	0.4878	0.081*
H12C	0.5629	0.3544	0.4537	0.081*
C21	0.59360 (13)	0.44990 (12)	0.59569 (8)	0.0533 (4)
H21A	0.6505	0.4617	0.5670	0.080*
H21B	0.5942	0.5071	0.6291	0.080*
H21C	0.5301	0.4540	0.5709	0.080*
C22	0.69696 (10)	0.33235 (13)	0.66072 (8)	0.0501 (3)
H22A	0.7531	0.3352	0.6307	0.075*
H22B	0.6988	0.2619	0.6841	0.075*
H22C	0.7030	0.3937	0.6913	0.075*
C31	0.68988 (10)	0.06920 (12)	0.57922 (7)	0.0474 (3)
H31A	0.6982	−0.0108	0.5731	0.057*
H31B	0.7463	0.0979	0.6052	0.057*
H31C	0.6885	0.1061	0.5373	0.057*
C32	0.59875 (13)	0.03606 (14)	0.67380 (7)	0.0561 (4)
H32A	0.6057	−0.0440	0.6677	0.084*
H32B	0.5361	0.0516	0.6965	0.084*
H32C	0.6564	0.0639	0.6991	0.084*
C41	0.34632 (11)	0.11493 (15)	0.63898 (8)	0.0555 (4)
H41A	0.3036	0.1123	0.6001	0.083*
H41B	0.3036	0.1151	0.6769	0.083*
H41C	0.3906	0.0500	0.6403	0.083*
C42	0.34249 (10)	0.31184 (15)	0.63825 (8)	0.0526 (4)
H42A	0.2979	0.3102	0.6002	0.079*
H42B	0.3841	0.3789	0.6373	0.079*
H42C	0.3017	0.3119	0.6771	0.079*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0424 (2)	0.0394 (2)	0.03566 (19)	0.000	−0.00112 (14)	0.000
K2	0.1055 (4)	0.0351 (2)	0.0709 (3)	0.0086 (3)	−0.0445 (3)	−0.0172 (2)
Al	0.02602 (16)	0.02410 (17)	0.03224 (17)	−0.00161 (12)	−0.00140 (12)	−0.00017 (12)
O1S	0.0558 (8)	0.0413 (8)	0.0586 (9)	0.000	−0.0084 (7)	0.000
N1	0.0381 (5)	0.0367 (6)	0.0335 (5)	0.0005 (4)	−0.0032 (4)	0.0051 (4)
N2	0.0341 (5)	0.0293 (5)	0.0488 (6)	−0.0068 (4)	−0.0032 (4)	−0.0014 (4)
N3	0.0348 (5)	0.0297 (5)	0.0369 (5)	0.0023 (4)	−0.0034 (4)	0.0035 (4)
N4	0.0268 (4)	0.0388 (6)	0.0418 (5)	−0.0039 (4)	0.0001 (4)	−0.0010 (4)
C1S	0.0516 (8)	0.0589 (10)	0.0732 (11)	−0.0001 (7)	−0.0148 (7)	−0.0021 (8)
C2S	0.0924 (17)	0.0547 (13)	0.167 (3)	−0.0215 (11)	−0.0594 (17)	0.0213 (14)
C11	0.0500 (8)	0.0513 (8)	0.0473 (7)	0.0007 (6)	−0.0152 (6)	0.0074 (6)
C12	0.0571 (9)	0.0629 (10)	0.0433 (7)	0.0029 (7)	0.0091 (6)	0.0151 (7)
C21	0.0656 (9)	0.0294 (7)	0.0650 (9)	−0.0119 (6)	0.0007 (7)	0.0004 (6)
C22	0.0353 (6)	0.0531 (9)	0.0615 (9)	−0.0094 (6)	−0.0054 (6)	−0.0121 (7)
C31	0.0379 (6)	0.0431 (8)	0.0611 (8)	0.0102 (6)	−0.0014 (6)	0.0014 (6)
C32	0.0657 (10)	0.0530 (9)	0.0494 (8)	0.0089 (7)	−0.0050 (7)	0.0171 (7)
C41	0.0431 (7)	0.0640 (10)	0.0593 (9)	−0.0239 (7)	0.0007 (6)	0.0040 (7)
C42	0.0341 (6)	0.0654 (10)	0.0581 (9)	0.0127 (6)	−0.0050 (6)	−0.0092 (7)

Geometric parameters (Å, º) top

K1—O1S	2.7133 (18)	N3—C31	1.4521 (17)
K1—N4ⁱ	2.9274 (12)	N4—C42	1.4506 (18)
K1—N4	2.9275 (12)	N4—C41	1.4522 (18)
K1—N2	2.9553 (14)	C1S—C2S	1.472 (3)
K1—N2ⁱ	2.9553 (14)	C1S—H1SA	0.9900
K1—C42ⁱ	3.1026 (16)	C1S—H1SB	0.9900
K1—C42	3.1026 (16)	C2S—C2Sⁱ	1.431 (4)
K1—C22ⁱ	3.2306 (17)	C2S—H2SA	0.9900
K1—C22	3.2307 (17)	C2S—H2SB	0.9900
K1—Alⁱ	3.4662 (11)	C11—H11A	0.9800
K1—Al	3.4662 (11)	C11—H11B	0.9800
K2—N1	2.8402 (14)	C11—H11C	0.9800
K2—N1ⁱⁱ	2.8402 (14)	C12—H12A	0.9800
K2—N3ⁱⁱ	2.8506 (12)	C12—H12B	0.9800
K2—N3	2.8506 (12)	C12—H12C	0.9800
K2—C31ⁱⁱ	3.0990 (16)	C21—H21A	0.9800
K2—C31	3.0991 (16)	C21—H21B	0.9800
K2—C11ⁱⁱ	3.2103 (18)	C21—H21C	0.9800
K2—C11	3.2103 (18)	C22—H22A	0.9800
K2—Alⁱⁱ	3.3649 (9)	C22—H22B	0.9800
K2—Al	3.3649 (9)	C22—H22C	0.9800
K2—H31A	3.0156	C31—H31A	0.9807
K2—H31C	2.9013	C31—H31B	0.9791
Al—N2	1.8383 (11)	C31—H31C	0.9800
Al—N1	1.8457 (12)	C32—H32A	0.9800
Al—N4	1.8533 (11)	C32—H32B	0.9800
Al—N3	1.8554 (11)	C32—H32C	0.9800
O1S—C1S	1.4215 (19)	C41—H41A	0.9800
O1S—C1Sⁱ	1.4215 (19)	C41—H41B	0.9800
N1—C11	1.4446 (17)	C41—H41C	0.9800
N1—C12	1.4478 (17)	C42—H42A	0.9800
N2—C22	1.4433 (17)	C42—H42B	0.9800
N2—C21	1.4522 (18)	C42—H42C	0.9800
N3—C32	1.4464 (17)

O1S—K1—N4ⁱ	116.93 (2)	H31A—K2—H31C	31.3
O1S—K1—N4	116.93 (2)	N2—Al—N1	110.41 (5)
N4ⁱ—K1—N4	126.15 (5)	N2—Al—N4	109.88 (5)
O1S—K1—N2	86.06 (2)	N1—Al—N4	110.02 (5)
N4ⁱ—K1—N2	122.31 (3)	N2—Al—N3	111.17 (5)
N4—K1—N2	61.81 (3)	N1—Al—N3	108.54 (5)
O1S—K1—N2ⁱ	86.07 (2)	N4—Al—N3	106.74 (5)
N4ⁱ—K1—N2ⁱ	61.81 (3)	N2—Al—K2	151.29 (4)
N4—K1—N2ⁱ	122.31 (3)	N1—Al—K2	57.56 (4)
N2—K1—N2ⁱ	172.13 (4)	N4—Al—K2	98.83 (4)
O1S—K1—C42ⁱ	92.87 (3)	N3—Al—K2	57.88 (4)
N4ⁱ—K1—C42ⁱ	27.65 (4)	N2—Al—K1	58.49 (4)
N4—K1—C42ⁱ	147.19 (4)	N1—Al—K1	149.91 (4)
N2—K1—C42ⁱ	110.37 (4)	N4—Al—K1	57.63 (3)
N2ⁱ—K1—C42ⁱ	70.05 (4)	N3—Al—K1	101.48 (4)
O1S—K1—C42	92.87 (3)	K2—Al—K1	145.105 (13)
N4ⁱ—K1—C42	147.19 (4)	C1S—O1S—C1Sⁱ	109.46 (18)
N4—K1—C42	27.64 (4)	C1S—O1S—K1	125.27 (9)
N2—K1—C42	70.05 (4)	C1Sⁱ—O1S—K1	125.27 (9)
N2ⁱ—K1—C42	110.37 (4)	C11—N1—C12	110.11 (11)
C42ⁱ—K1—C42	174.26 (7)	C11—N1—Al	124.45 (9)
O1S—K1—C22ⁱ	88.36 (3)	C12—N1—Al	121.72 (9)
N4ⁱ—K1—C22ⁱ	83.60 (4)	C11—N1—K2	91.07 (8)
N4—K1—C22ⁱ	97.90 (4)	C12—N1—K2	110.00 (9)
N2—K1—C22ⁱ	152.99 (3)	Al—N1—K2	89.18 (4)
N2ⁱ—K1—C22ⁱ	26.51 (3)	C22—N2—C21	110.49 (11)
C42ⁱ—K1—C22ⁱ	96.27 (4)	C22—N2—Al	124.23 (9)
C42—K1—C22ⁱ	83.89 (5)	C21—N2—Al	121.43 (9)
O1S—K1—C22	88.36 (3)	C22—N2—K1	87.45 (8)
N4ⁱ—K1—C22	97.90 (4)	C21—N2—K1	113.62 (9)
N4—K1—C22	83.60 (4)	Al—N2—K1	89.48 (4)
N2—K1—C22	26.51 (3)	C32—N3—C31	109.13 (11)
N2ⁱ—K1—C22	153.00 (3)	C32—N3—Al	123.79 (10)
C42ⁱ—K1—C22	83.89 (5)	C31—N3—Al	118.63 (9)
C42—K1—C22	96.27 (5)	C32—N3—K2	124.05 (9)
C22ⁱ—K1—C22	176.73 (6)	C31—N3—K2	85.63 (8)
O1S—K1—Alⁱ	110.839 (12)	Al—N3—K2	88.67 (4)
N4ⁱ—K1—Alⁱ	32.32 (2)	C42—N4—C41	110.02 (12)
N4—K1—Alⁱ	121.53 (3)	C42—N4—Al	118.47 (10)
N2—K1—Alⁱ	153.72 (2)	C41—N4—Al	122.18 (10)
N2ⁱ—K1—Alⁱ	32.03 (2)	C42—N4—K1	82.91 (8)
C42ⁱ—K1—Alⁱ	50.99 (3)	C41—N4—K1	126.56 (9)
C42—K1—Alⁱ	126.43 (4)	Al—N4—K1	90.05 (4)
C22ⁱ—K1—Alⁱ	51.29 (3)	O1S—C1S—C2S	106.52 (14)
C22—K1—Alⁱ	130.21 (3)	O1S—C1S—H1SA	110.4
O1S—K1—Al	110.838 (12)	C2S—C1S—H1SA	110.4
N4ⁱ—K1—Al	121.53 (3)	O1S—C1S—H1SB	110.4
N4—K1—Al	32.32 (2)	C2S—C1S—H1SB	110.4
N2—K1—Al	32.03 (2)	H1SA—C1S—H1SB	108.6
N2ⁱ—K1—Al	153.72 (3)	C2Sⁱ—C2S—C1S	106.16 (14)
C42ⁱ—K1—Al	126.43 (4)	C2Sⁱ—C2S—H2SA	110.5
C42—K1—Al	50.99 (3)	C1S—C2S—H2SA	110.5
C22ⁱ—K1—Al	130.21 (3)	C2Sⁱ—C2S—H2SB	110.5
C22—K1—Al	51.29 (3)	C1S—C2S—H2SB	110.5
Alⁱ—K1—Al	138.32 (2)	H2SA—C2S—H2SB	108.7
N1—K2—N1ⁱⁱ	180.0	N1—C11—K2	62.19 (7)
N1—K2—N3ⁱⁱ	116.27 (3)	N1—C11—H11A	109.5
N1ⁱⁱ—K2—N3ⁱⁱ	63.73 (3)	K2—C11—H11A	71.2
N1—K2—N3	63.73 (3)	N1—C11—H11B	109.5
N1ⁱⁱ—K2—N3	116.26 (3)	K2—C11—H11B	170.5
N3ⁱⁱ—K2—N3	179.999 (1)	H11A—C11—H11B	109.5
N1—K2—C31ⁱⁱ	108.71 (3)	N1—C11—H11C	109.5
N1ⁱⁱ—K2—C31ⁱⁱ	71.29 (3)	K2—C11—H11C	78.6
N3ⁱⁱ—K2—C31ⁱⁱ	27.85 (3)	H11A—C11—H11C	109.5
N3—K2—C31ⁱⁱ	152.15 (3)	H11B—C11—H11C	109.5
N1—K2—C31	71.29 (3)	N1—C12—H12A	109.5
N1ⁱⁱ—K2—C31	108.71 (3)	N1—C12—H12B	109.5
N3ⁱⁱ—K2—C31	152.15 (3)	H12A—C12—H12B	109.5
N3—K2—C31	27.85 (3)	N1—C12—H12C	109.5
C31ⁱⁱ—K2—C31	180.0	H12A—C12—H12C	109.5
N1—K2—C11ⁱⁱ	153.26 (3)	H12B—C12—H12C	109.5
N1ⁱⁱ—K2—C11ⁱⁱ	26.74 (3)	N2—C21—H21A	109.5
N3ⁱⁱ—K2—C11ⁱⁱ	85.98 (4)	N2—C21—H21B	109.5
N3—K2—C11ⁱⁱ	94.02 (4)	H21A—C21—H21B	109.5
C31ⁱⁱ—K2—C11ⁱⁱ	97.83 (4)	N2—C21—H21C	109.5
C31—K2—C11ⁱⁱ	82.17 (4)	H21A—C21—H21C	109.5
N1—K2—C11	26.74 (3)	H21B—C21—H21C	109.5
N1ⁱⁱ—K2—C11	153.26 (3)	N2—C22—K1	66.04 (7)
N3ⁱⁱ—K2—C11	94.02 (4)	N2—C22—H22A	109.5
N3—K2—C11	85.98 (4)	K1—C22—H22A	175.5
C31ⁱⁱ—K2—C11	82.17 (4)	N2—C22—H22B	109.5
C31—K2—C11	97.83 (4)	K1—C22—H22B	72.8
C11ⁱⁱ—K2—C11	180.0	H22A—C22—H22B	109.5
N1—K2—Alⁱⁱ	146.74 (2)	N2—C22—H22C	109.5
N1ⁱⁱ—K2—Alⁱⁱ	33.26 (2)	K1—C22—H22C	72.9
N3ⁱⁱ—K2—Alⁱⁱ	33.45 (2)	H22A—C22—H22C	109.5
N3—K2—Alⁱⁱ	146.55 (2)	H22B—C22—H22C	109.5
C31ⁱⁱ—K2—Alⁱⁱ	52.16 (3)	N3—C31—K2	66.52 (7)
C31—K2—Alⁱⁱ	127.84 (3)	N3—C31—H31A	109.5
C11ⁱⁱ—K2—Alⁱⁱ	52.61 (3)	K2—C31—H31A	76.0
C11—K2—Alⁱⁱ	127.39 (3)	N3—C31—H31B	109.4
N1—K2—Al	33.26 (2)	K2—C31—H31B	174.3
N1ⁱⁱ—K2—Al	146.74 (2)	H31A—C31—H31B	109.5
N3ⁱⁱ—K2—Al	146.55 (2)	N3—C31—H31C	109.5
N3—K2—Al	33.45 (2)	K2—C31—H31C	69.3
C31ⁱⁱ—K2—Al	127.84 (3)	H31A—C31—H31C	109.4
C31—K2—Al	52.16 (3)	H31B—C31—H31C	109.4
C11ⁱⁱ—K2—Al	127.39 (3)	N3—C32—H32A	109.5
C11—K2—Al	52.61 (3)	N3—C32—H32B	109.5
Alⁱⁱ—K2—Al	180.0	H32A—C32—H32B	109.5
N1—K2—H31A	89.5	N3—C32—H32C	109.5
N1ⁱⁱ—K2—H31A	90.5	H32A—C32—H32C	109.5
N3ⁱⁱ—K2—H31A	140.2	H32B—C32—H32C	109.5
N3—K2—H31A	39.8	N4—C41—H41A	109.5
C31ⁱⁱ—K2—H31A	161.6	N4—C41—H41B	109.5
C31—K2—H31A	18.4	H41A—C41—H41B	109.5
C11ⁱⁱ—K2—H31A	63.8	N4—C41—H41C	109.5
C11—K2—H31A	116.2	H41A—C41—H41C	109.5
Alⁱⁱ—K2—H31A	110.7	H41B—C41—H41C	109.5
Al—K2—H31A	69.3	N4—C42—K1	69.45 (7)
N1—K2—H31C	61.5	N4—C42—H42A	109.5
N1ⁱⁱ—K2—H31C	118.5	K1—C42—H42A	174.5
N3ⁱⁱ—K2—H31C	139.2	N4—C42—H42B	109.5
N3—K2—H31C	40.8	K1—C42—H42B	66.5
C31ⁱⁱ—K2—H31C	161.6	H42A—C42—H42B	109.5
C31—K2—H31C	18.4	N4—C42—H42C	109.5
C11ⁱⁱ—K2—H31C	92.1	K1—C42—H42C	75.8
C11—K2—H31C	87.9	H42A—C42—H42C	109.5
Alⁱⁱ—K2—H31C	126.8	H42B—C42—H42C	109.5
Al—K2—H31C	53.2

N1—K2—Al—N2	−72.54 (9)	K1—Al—N2—C21	−117.65 (12)
N1ⁱⁱ—K2—Al—N2	107.46 (9)	N1—Al—N2—K1	148.73 (4)
N3ⁱⁱ—K2—Al—N2	−104.99 (9)	N4—Al—N2—K1	27.20 (5)
N3—K2—Al—N2	75.01 (9)	N3—Al—N2—K1	−90.74 (5)
C31ⁱⁱ—K2—Al—N2	−136.20 (9)	K2—Al—N2—K1	−152.06 (5)
C31—K2—Al—N2	43.80 (9)	O1S—K1—N2—C22	94.23 (7)
C11ⁱⁱ—K2—Al—N2	79.62 (9)	N4ⁱ—K1—N2—C22	−25.34 (9)
C11—K2—Al—N2	−100.37 (9)	N4—K1—N2—C22	−142.28 (9)
Alⁱⁱ—K2—Al—N2	−90.4 (6)	N2ⁱ—K1—N2—C22	94.24 (8)
N1ⁱⁱ—K2—Al—N1	180.0	C42ⁱ—K1—N2—C22	2.63 (9)
N3ⁱⁱ—K2—Al—N1	−32.45 (6)	C42—K1—N2—C22	−171.27 (9)
N3—K2—Al—N1	147.55 (6)	C22ⁱ—K1—N2—C22	172.81 (13)
C31ⁱⁱ—K2—Al—N1	−63.66 (5)	Alⁱ—K1—N2—C22	−37.53 (10)
C31—K2—Al—N1	116.34 (5)	Al—K1—N2—C22	−124.29 (9)
C11ⁱⁱ—K2—Al—N1	152.16 (5)	O1S—K1—N2—C21	−17.06 (9)
C11—K2—Al—N1	−27.84 (5)	N4ⁱ—K1—N2—C21	−136.63 (9)
Alⁱⁱ—K2—Al—N1	−17.8 (6)	N4—K1—N2—C21	106.44 (9)
N1—K2—Al—N4	108.17 (5)	N2ⁱ—K1—N2—C21	−17.05 (9)
N1ⁱⁱ—K2—Al—N4	−71.83 (5)	C42ⁱ—K1—N2—C21	−108.66 (9)
N3ⁱⁱ—K2—Al—N4	75.72 (5)	C42—K1—N2—C21	77.44 (9)
N3—K2—Al—N4	−104.28 (5)	C22ⁱ—K1—N2—C21	61.52 (13)
C31ⁱⁱ—K2—Al—N4	44.51 (5)	C22—K1—N2—C21	−111.29 (12)
C31—K2—Al—N4	−135.49 (5)	Alⁱ—K1—N2—C21	−148.81 (8)
C11ⁱⁱ—K2—Al—N4	−99.67 (5)	Al—K1—N2—C21	124.42 (10)
C11—K2—Al—N4	80.33 (5)	O1S—K1—N2—Al	−141.47 (4)
Alⁱⁱ—K2—Al—N4	90.3 (6)	N4ⁱ—K1—N2—Al	98.95 (5)
N1—K2—Al—N3	−147.55 (6)	N4—K1—N2—Al	−17.98 (3)
N1ⁱⁱ—K2—Al—N3	32.45 (6)	N2ⁱ—K1—N2—Al	−141.47 (4)
N3ⁱⁱ—K2—Al—N3	179.998 (1)	C42ⁱ—K1—N2—Al	126.92 (5)
C31ⁱⁱ—K2—Al—N3	148.79 (5)	C42—K1—N2—Al	−46.98 (5)
C31—K2—Al—N3	−31.21 (5)	C22ⁱ—K1—N2—Al	−62.89 (10)
C11ⁱⁱ—K2—Al—N3	4.61 (5)	C22—K1—N2—Al	124.29 (9)
C11—K2—Al—N3	−175.39 (5)	Alⁱ—K1—N2—Al	86.77 (6)
Alⁱⁱ—K2—Al—N3	−165.4 (5)	N2—Al—N3—C32	78.67 (12)
N1—K2—Al—K1	151.74 (5)	N1—Al—N3—C32	−159.71 (11)
N1ⁱⁱ—K2—Al—K1	−28.26 (5)	N4—Al—N3—C32	−41.15 (12)
N3ⁱⁱ—K2—Al—K1	119.29 (4)	K2—Al—N3—C32	−131.18 (12)
N3—K2—Al—K1	−60.71 (4)	K1—Al—N3—C32	18.22 (11)
C31ⁱⁱ—K2—Al—K1	88.08 (4)	N2—Al—N3—C31	−65.87 (11)
C31—K2—Al—K1	−91.92 (4)	N1—Al—N3—C31	55.76 (10)
C11ⁱⁱ—K2—Al—K1	−56.10 (4)	N4—Al—N3—C31	174.31 (9)
C11—K2—Al—K1	123.91 (4)	K2—Al—N3—C31	84.29 (10)
Alⁱⁱ—K2—Al—K1	133.9 (5)	K1—Al—N3—C31	−126.31 (9)
O1S—K1—Al—N2	41.68 (4)	N2—Al—N3—K2	−150.16 (4)
N4ⁱ—K1—Al—N2	−101.64 (5)	N1—Al—N3—K2	−28.53 (5)
N4—K1—Al—N2	149.41 (6)	N4—Al—N3—K2	90.02 (5)
N2ⁱ—K1—Al—N2	168.89 (6)	K1—Al—N3—K2	149.395 (19)
C42ⁱ—K1—Al—N2	−68.66 (6)	N1—K2—N3—C32	150.13 (11)
C42—K1—Al—N2	117.83 (6)	N1ⁱⁱ—K2—N3—C32	−29.87 (11)
C22ⁱ—K1—Al—N2	148.04 (6)	N3ⁱⁱ—K2—N3—C32	10 (12)
C22—K1—Al—N2	−28.19 (5)	C31ⁱⁱ—K2—N3—C32	69.82 (13)
Alⁱ—K1—Al—N2	−138.33 (4)	C31—K2—N3—C32	−110.18 (13)
O1S—K1—Al—N1	−34.33 (7)	C11ⁱⁱ—K2—N3—C32	−45.36 (11)
N4ⁱ—K1—Al—N1	−177.64 (7)	C11—K2—N3—C32	134.65 (11)
N4—K1—Al—N1	73.41 (8)	Alⁱⁱ—K2—N3—C32	−49.03 (12)
N2—K1—Al—N1	−76.00 (8)	Al—K2—N3—C32	130.97 (12)
N2ⁱ—K1—Al—N1	92.89 (9)	N1—K2—N3—C31	−99.69 (8)
C42ⁱ—K1—Al—N1	−144.66 (8)	N1ⁱⁱ—K2—N3—C31	80.31 (8)
C42—K1—Al—N1	41.82 (8)	N3ⁱⁱ—K2—N3—C31	121 (12)
C22ⁱ—K1—Al—N1	72.04 (8)	C31ⁱⁱ—K2—N3—C31	180.0
C22—K1—Al—N1	−104.20 (8)	C11ⁱⁱ—K2—N3—C31	64.83 (8)
Alⁱ—K1—Al—N1	145.67 (7)	C11—K2—N3—C31	−115.17 (8)
O1S—K1—Al—N4	−107.73 (4)	Alⁱⁱ—K2—N3—C31	61.15 (8)
N4ⁱ—K1—Al—N4	108.95 (6)	Al—K2—N3—C31	−118.84 (8)
N2—K1—Al—N4	−149.41 (6)	N1—K2—N3—Al	19.16 (3)
N2ⁱ—K1—Al—N4	19.48 (7)	N1ⁱⁱ—K2—N3—Al	−160.84 (3)
C42ⁱ—K1—Al—N4	141.93 (6)	N3ⁱⁱ—K2—N3—Al	−121 (12)
C42—K1—Al—N4	−31.58 (6)	C31ⁱⁱ—K2—N3—Al	−61.15 (8)
C22ⁱ—K1—Al—N4	−1.37 (6)	C31—K2—N3—Al	118.84 (8)
C22—K1—Al—N4	−177.60 (6)	C11ⁱⁱ—K2—N3—Al	−176.33 (4)
Alⁱ—K1—Al—N4	72.26 (4)	C11—K2—N3—Al	3.67 (4)
O1S—K1—Al—N3	149.60 (3)	Alⁱⁱ—K2—N3—Al	180.0
N4ⁱ—K1—Al—N3	6.28 (4)	N2—Al—N4—C42	54.48 (11)
N4—K1—Al—N3	−102.67 (5)	N1—Al—N4—C42	−67.29 (11)
N2—K1—Al—N3	107.92 (6)	N3—Al—N4—C42	175.13 (9)
N2ⁱ—K1—Al—N3	−83.18 (6)	K2—Al—N4—C42	−125.88 (9)
C42ⁱ—K1—Al—N3	39.26 (5)	K1—Al—N4—C42	81.96 (10)
C42—K1—Al—N3	−134.25 (6)	N2—Al—N4—C41	−162.25 (10)
C22ⁱ—K1—Al—N3	−104.04 (5)	N1—Al—N4—C41	75.98 (12)
C22—K1—Al—N3	79.73 (5)	N3—Al—N4—C41	−41.60 (12)
Alⁱ—K1—Al—N3	−30.40 (3)	K2—Al—N4—C41	17.39 (11)
O1S—K1—Al—K2	−161.489 (17)	K1—Al—N4—C41	−134.78 (12)
N4ⁱ—K1—Al—K2	55.20 (4)	N2—Al—N4—K1	−27.47 (5)
N4—K1—Al—K2	−53.75 (4)	N1—Al—N4—K1	−149.24 (4)
N2—K1—Al—K2	156.84 (5)	N3—Al—N4—K1	93.17 (5)
N2ⁱ—K1—Al—K2	−34.27 (6)	K2—Al—N4—K1	152.17 (2)
C42ⁱ—K1—Al—K2	88.18 (4)	O1S—K1—N4—C42	−31.94 (8)
C42—K1—Al—K2	−85.34 (5)	N4ⁱ—K1—N4—C42	148.06 (8)
C22ⁱ—K1—Al—K2	−55.12 (4)	N2—K1—N4—C42	−100.87 (9)
C22—K1—Al—K2	128.64 (4)	N2ⁱ—K1—N4—C42	71.36 (9)
Alⁱ—K1—Al—K2	18.510 (17)	C42ⁱ—K1—N4—C42	175.00 (6)
N4ⁱ—K1—O1S—C1S	37.19 (10)	C22ⁱ—K1—N4—C42	60.24 (8)
N4—K1—O1S—C1S	−142.81 (10)	C22—K1—N4—C42	−116.82 (9)
N2—K1—O1S—C1S	−87.28 (10)	Alⁱ—K1—N4—C42	109.28 (8)
N2ⁱ—K1—O1S—C1S	92.72 (10)	Al—K1—N4—C42	−118.70 (10)
C42ⁱ—K1—O1S—C1S	22.96 (10)	O1S—K1—N4—C41	−141.66 (11)
C42—K1—O1S—C1S	−157.04 (10)	N4ⁱ—K1—N4—C41	38.34 (11)
C22ⁱ—K1—O1S—C1S	119.16 (10)	N2—K1—N4—C41	149.41 (12)
C22—K1—O1S—C1S	−60.84 (10)	N2ⁱ—K1—N4—C41	−38.35 (12)
Alⁱ—K1—O1S—C1S	72.02 (10)	C42ⁱ—K1—N4—C41	65.28 (13)
Al—K1—O1S—C1S	−107.98 (10)	C42—K1—N4—C41	−109.71 (14)
N4ⁱ—K1—O1S—C1Sⁱ	−142.81 (10)	C22ⁱ—K1—N4—C41	−49.47 (12)
N4—K1—O1S—C1Sⁱ	37.19 (10)	C22—K1—N4—C41	133.46 (12)
N2—K1—O1S—C1Sⁱ	92.72 (10)	Alⁱ—K1—N4—C41	−0.43 (12)
N2ⁱ—K1—O1S—C1Sⁱ	−87.28 (10)	Al—K1—N4—C41	131.58 (13)
C42ⁱ—K1—O1S—C1Sⁱ	−157.04 (10)	O1S—K1—N4—Al	86.76 (4)
C42—K1—O1S—C1Sⁱ	22.96 (10)	N4ⁱ—K1—N4—Al	−93.24 (4)
C22ⁱ—K1—O1S—C1Sⁱ	−60.84 (10)	N2—K1—N4—Al	17.83 (3)
C22—K1—O1S—C1Sⁱ	119.16 (10)	N2ⁱ—K1—N4—Al	−169.94 (4)
Alⁱ—K1—O1S—C1Sⁱ	−107.98 (10)	C42ⁱ—K1—N4—Al	−66.30 (8)
Al—K1—O1S—C1Sⁱ	72.02 (10)	C42—K1—N4—Al	118.70 (9)
N2—Al—N1—C11	−118.54 (11)	C22ⁱ—K1—N4—Al	178.95 (4)
N4—Al—N1—C11	2.91 (13)	C22—K1—N4—Al	1.88 (5)
N3—Al—N1—C11	119.37 (11)	Alⁱ—K1—N4—Al	−132.01 (3)
K2—Al—N1—C11	90.73 (11)	C1Sⁱ—O1S—C1S—C2S	−7.13 (16)
K1—Al—N1—C11	−56.57 (15)	K1—O1S—C1S—C2S	172.87 (16)
N2—Al—N1—C12	37.57 (12)	O1S—C1S—C2S—C2Sⁱ	19.0 (4)
N4—Al—N1—C12	159.02 (11)	C12—N1—C11—K2	111.78 (11)
N3—Al—N1—C12	−84.52 (12)	Al—N1—C11—K2	−89.74 (9)
K2—Al—N1—C12	−113.16 (12)	N1ⁱⁱ—K2—C11—N1	180.0
K1—Al—N1—C12	99.54 (12)	N3ⁱⁱ—K2—C11—N1	−147.85 (8)
N2—Al—N1—K2	150.73 (4)	N3—K2—C11—N1	32.15 (8)
N4—Al—N1—K2	−87.82 (5)	C31ⁱⁱ—K2—C11—N1	−173.11 (8)
N3—Al—N1—K2	28.64 (5)	C31—K2—C11—N1	6.88 (8)
K1—Al—N1—K2	−147.30 (5)	C11ⁱⁱ—K2—C11—N1	−88 (10)
N1ⁱⁱ—K2—N1—C11	−116 (15)	Alⁱⁱ—K2—C11—N1	−145.30 (6)
N3ⁱⁱ—K2—N1—C11	36.29 (8)	Al—K2—C11—N1	34.70 (6)
N3—K2—N1—C11	−143.71 (8)	C21—N2—C22—K1	114.31 (10)
C31ⁱⁱ—K2—N1—C11	7.20 (9)	Al—N2—C22—K1	−87.64 (9)
C31—K2—N1—C11	−172.80 (9)	O1S—K1—C22—N2	−84.46 (7)
C11ⁱⁱ—K2—N1—C11	180.0	N4ⁱ—K1—C22—N2	158.58 (7)
Alⁱⁱ—K2—N1—C11	55.55 (9)	N4—K1—C22—N2	32.87 (7)
Al—K2—N1—C11	−124.45 (9)	N2ⁱ—K1—C22—N2	−162.50 (10)
N1ⁱⁱ—K2—N1—C12	132 (15)	C42ⁱ—K1—C22—N2	−177.52 (8)
N3ⁱⁱ—K2—N1—C12	−75.59 (9)	C42—K1—C22—N2	8.25 (8)
N3—K2—N1—C12	104.41 (9)	C22ⁱ—K1—C22—N2	−84.45 (7)
C31ⁱⁱ—K2—N1—C12	−104.68 (9)	Alⁱ—K1—C22—N2	159.32 (6)
C31—K2—N1—C12	75.32 (9)	Al—K1—C22—N2	34.16 (6)
C11ⁱⁱ—K2—N1—C12	68.11 (12)	C32—N3—C31—K2	124.60 (11)
C11—K2—N1—C12	−111.88 (12)	Al—N3—C31—K2	−86.09 (7)
Alⁱⁱ—K2—N1—C12	−56.33 (10)	N1—K2—C31—N3	68.95 (7)
Al—K2—N1—C12	123.67 (10)	N1ⁱⁱ—K2—C31—N3	−111.05 (7)
N1ⁱⁱ—K2—N1—Al	8 (15)	N3ⁱⁱ—K2—C31—N3	180.0
N3ⁱⁱ—K2—N1—Al	160.74 (3)	C31ⁱⁱ—K2—C31—N3	167 (13)
N3—K2—N1—Al	−19.26 (3)	C11ⁱⁱ—K2—C31—N3	−114.31 (8)
C31ⁱⁱ—K2—N1—Al	131.65 (4)	C11—K2—C31—N3	65.69 (8)
C31—K2—N1—Al	−48.35 (4)	Alⁱⁱ—K2—C31—N3	−142.31 (6)
C11ⁱⁱ—K2—N1—Al	−55.56 (9)	Al—K2—C31—N3	37.69 (6)
C11—K2—N1—Al	124.45 (9)	C41—N4—C42—K1	126.41 (10)
Alⁱⁱ—K2—N1—Al	180.0	Al—N4—C42—K1	−86.19 (7)
N1—Al—N2—C22	−124.71 (11)	O1S—K1—C42—N4	151.82 (7)
N4—Al—N2—C22	113.76 (11)	N4ⁱ—K1—C42—N4	−52.04 (12)
N3—Al—N2—C22	−4.18 (12)	N2—K1—C42—N4	67.05 (7)
K2—Al—N2—C22	−65.50 (15)	N2ⁱ—K1—C42—N4	−121.32 (7)
K1—Al—N2—C22	86.56 (11)	C42ⁱ—K1—C42—N4	−28.18 (8)
N1—Al—N2—C21	31.07 (12)	C22ⁱ—K1—C42—N4	−120.14 (8)
N4—Al—N2—C21	−90.46 (12)	C22—K1—C42—N4	63.15 (8)
N3—Al—N2—C21	151.60 (10)	Alⁱ—K1—C42—N4	−89.52 (8)
K2—Al—N2—C21	90.28 (13)	Al—K1—C42—N4	37.12 (6)

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

Experimental details

Crystal data
Chemical formula	[Al₂K₂(C₂H₆N)₈(C₄H₈O)]
M_r	556.88
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	13.247 (4), 12.075 (4), 20.822 (7)
β (°)	90.979 (5)
V (Å³)	3330.1 (19)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.36
Crystal size (mm)	0.74 × 0.57 × 0.42

Data collection
Diffractometer	Bruker SMART APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2008)
T_min, T_max	0.776, 0.863
No. of measured, independent and observed [I > 2σ(I)] reflections	18795, 4928, 3986
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.723

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.107, 1.03
No. of reflections	4928
No. of parameters	155
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.30

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXTL (Sheldrick, 2008).

Footnotes

‡Chemistry Division, Code 6123.

§Code 6900.

Acknowledgements

We thank The Office of Naval Research for financial support.

References

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