Bis(1,1,3,3-tetra­methyl-1,3-dibenzoatodistannoxane)

In centrosymmetric octa­methyl-1κ²C,2κ²C,3κ²C,4κ²C-tetra­kis-μ-benzoato-1:2κ²O,O′;2:3κ²O;3:4κ²O,O′;1:4κ²O-bis-μ₃-oxo-1:2:3k³O;1:3:4k³O-tetratin, [[(CH₃)₂SnO₂CC₆H₅]₂O]₂; the exocyclic Sn atom is five-coordinated and has a trans–C₃SnO₂ trigonal bipyramidal geometry [C—Sn—C = 139.4 (2)°] and the endocyclic Sn atom is six-coordinated and has a severely distorted trans-C₂SnO₄ octahedral geometry [C—Sn—C = 145.6 (2)°].

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.034
• wR factor = 0.080
• Data-to-parameter ratio = 20.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

In the supramolecular self-assembled structures of dimeric 1,1,3,3-tetraorgano-1,3-dicarboxylatodistannoxanes, the monomeric R₂(R'CO₂)Sn—O—Sn(O₂CR')R₂ moieties are linked by two dative Sn← O interactions involving their distannoxanyl O atoms. The dative bond is unusually short in such organotin compounds, these being typically as short as the covalent Sn—O bond, so that the covalent and dative bonds are not readily distinguished (Ng et al., 1991; Haiduc & Edelmann, 1999). The most common of the four types of such tetranuclear aggregates has two bridging and two monodentate carboxylate groups, and one Sn atom is five-coordinated, whereas the other is six-coordinated. The benzoate derivative, bis(1,1,3,3-tetramethyl-1,3-dibenzoatodistannoxane), (I), adopts this centrosymmetric conformation (Fig. 1). The five-coordinated Sn atom has a bent C₂Sn skeleton [C—Sn—C = 139.4 (2) Å], as does the six-coordinated Sn atom [C—Sn—C = 145.6 (2)°]. The five-coordinated Sn atom is bonded to a monodentate benzoate group, whose –CO₂ unit displays single and double C—O bonds. The single-bond atom O1 acts as a bridging atom forming a relatively short bond with the five-coordinated Sn atom [Sn1—O1 = 2.165 (3) Å] and a very long bond with the six-coordinated Sn atom [O1—Sn2ⁱ 2.800 (3) Å; symmetry code: (i) 1 − x, 1 − y, 1 − z]. The double-bond atom O2 is engaged in a weak C—H_Ar···O_CO interaction [C15···O2ⁱⁱ = 3.450 (6) Å and C—H···Oⁱⁱ = 165°; symmetry code: (ii) −1/2 + x, 3/2 − y, 1/2 + z], which links adjacent molecules into a layer structure (Fig. 2).

A number of the distannoxanes have been isolated as the products either from the condensation of a diorganotin oxide with two molar equivalents of the carboxylic acid, or from the metathetical reaction of a diorganotin halide with metal carboxylate (Tiekink, 1991a; Tiekink, 1994). The dicarboxylate that is initially formed is unstable with respect to hydrolysis to the distannoxane. An example is shown by dimethyltin diacetate, an air-sensitive compound (Lockhart et al., 1987) that can hydrolyze to the distannoxane (Lockhart et al., 1986). On the other hand, dimethyltin dibenzoate represents an exception as it is air-stable; the monomeric compound adopts a skew-trapezoidal bipyramidal geometry [C—Sn—C = 147.2 (7)°] (Tiekink, 1991b).

S2. Experimental

Dimethylphenyltin iodide was obtained by the cleavage of the tin–phenyl bond by elemental iodine (Davison & Rakita, 1970; Amini et al., 1989). In an attempt to synthesize dimethylphenyltin benzoate, equimolar quantities of dimethylphenyltin iodide (0.35 g, 1 mmol) and silver benzoate (0.23 g, 1 mmol) were dissolved in ethanol to give a precipitate that was presumed to be silver iodide. The precipitate was removed and the solvent evaporated off to furnish a white material. Crystals (m.p. 514–515 K) were grown from a methanol–toluene solvent system. In the ¹H NMR spectrum in CDCl₃, the tin–methyl coupling constant was 90 Hz.

S3. Refinement

H atoms were positioned geometrically and were allowed to ride on their parent C atoms, with U_iso(H) = 1.2U_eq(C) for the aromatic C atoms and U_iso(H) = 1.5U_eq(C) for the methyl C atoms.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. ORTEPII (Johnson, 1976) plot of the centrosymmetric 1,1,3,3-tetramethyl-1,3-dibenzoatodistannoxane dimer with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radii.
	Fig. 2. ORTEPII (Johnson, 1976) plot of the supramolecular C—H···O interactions in bis(1,1,3,3-tetramethyl-1,3-dibenzoatodistannoxane). H atoms have been omitted.

Octamethyl-1κ²C,2κ²C,3κ²C,4κ²C-tetrakis-µ-benzoato- 1:2κ²O,O';2:3κ²O;3:4κ²O,O';1:4κ²O-bis-µ₃-oxo- 1:2:3k³O;1:3:4k³O-tetratin

Crystal data

[Sn4O2(CH3)8(C7H5O2)4]	F(000) = 1080
Mr = 1111.47	Dx = 1.774 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.4001 (6) Å	Cell parameters from 3680 reflections
b = 20.952 (1) Å	θ = 1.9–27.5°
c = 11.2920 (7) Å	µ = 2.42 mm^−1
β = 110.671 (2)°	T = 293 K
V = 2080.8 (2) Å^3	Prism, colorless
Z = 2	0.15 × 0.05 × 0.03 mm

Data collection

Bruker CCD area-detector diffractometer	4785 independent reflections
Radiation source: rotating anode tube	3723 reflections with I > 2σ(I)'
Graphite monochromator	Rint = 0.041
ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −12→12
Tmin = 0.713, Tmax = 0.931	k = −27→27
20323 measured reflections	l = −14→14

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.080	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0227P)^2 + 0.958P] where P = (Fo^2 + 2Fc^2)/3
4785 reflections	(Δ/σ)max < 0.001
230 parameters	Δρmax = 0.69 e Å^−3
0 restraints	Δρmin = −0.32 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sn1	0.26923 (3)	0.62434 (1)	0.42276 (2)	0.0486 (1)
Sn2	0.44818 (3)	0.48241 (1)	0.62079 (2)	0.0470 (1)
O1	0.3761 (3)	0.6262 (1)	0.2815 (3)	0.059 (1)
O2	0.2225 (4)	0.7081 (1)	0.2134 (3)	0.066 (1)
O3	0.1815 (5)	0.6088 (2)	0.5801 (3)	0.103 (1)
O4	0.2867 (5)	0.5279 (2)	0.6996 (4)	0.099 (1)
O5	0.4060 (3)	0.5477 (2)	0.4790 (2)	0.050 (1)
C1	0.3804 (6)	0.7047 (2)	0.5243 (5)	0.084 (2)
C2	0.0514 (5)	0.5969 (3)	0.3013 (5)	0.076 (1)
C3	0.2861 (5)	0.4097 (2)	0.5528 (5)	0.077 (1)
C4	0.6196 (6)	0.5197 (2)	0.7790 (5)	0.082 (2)
C5	0.3215 (5)	0.6729 (2)	0.2031 (4)	0.053 (1)
C6	0.3864 (5)	0.6817 (2)	0.1003 (4)	0.056 (1)
C7	0.5113 (6)	0.6492 (3)	0.0992 (5)	0.081 (2)
C8	0.5698 (7)	0.6579 (3)	0.0035 (6)	0.103 (2)
C9	0.5015 (8)	0.7014 (4)	−0.0896 (5)	0.099 (2)
C10	0.3756 (8)	0.7343 (3)	−0.0908 (5)	0.093 (2)
C11	0.3195 (6)	0.7246 (2)	0.0045 (4)	0.074 (1)
C12	0.2023 (5)	0.5747 (2)	0.6735 (4)	0.054 (1)
C13	0.1207 (4)	0.5914 (2)	0.7614 (3)	0.046 (1)
C14	0.0156 (5)	0.6409 (2)	0.7312 (4)	0.058 (1)
C15	−0.0611 (5)	0.6558 (2)	0.8107 (4)	0.068 (1)
C16	−0.0330 (5)	0.6228 (2)	0.9215 (4)	0.067 (1)
C17	0.0703 (5)	0.5739 (2)	0.9519 (4)	0.064 (1)
C18	0.1463 (5)	0.5581 (2)	0.8717 (4)	0.058 (1)
H1a	0.3250	0.7205	0.5751	0.127*
H1b	0.3859	0.7372	0.4662	0.127*
H1c	0.4814	0.6931	0.5781	0.127*
H2a	0.0557	0.5849	0.2206	0.114*
H2b	−0.0178	0.6319	0.2905	0.114*
H2c	0.0169	0.5612	0.3374	0.114*
H3a	0.1928	0.4277	0.4965	0.116*
H3b	0.2684	0.3895	0.6227	0.116*
H3c	0.3231	0.3787	0.5082	0.116*
H4a	0.7170	0.5065	0.7780	0.123*
H4b	0.6067	0.5043	0.8546	0.123*
H4c	0.6138	0.5654	0.7770	0.123*
H7	0.5585	0.6206	0.1641	0.097*
H8	0.6537	0.6346	0.0026	0.124*
H9	0.5414	0.7087	−0.1529	0.119*
H10	0.3283	0.7629	−0.1557	0.111*
H11	0.2347	0.7475	0.0045	0.088*
H14	−0.0027	0.6640	0.6569	0.070*
H15	−0.1327	0.6885	0.7893	0.081*
H16	−0.0839	0.6335	0.9758	0.081*
H17	0.0892	0.5514	1.0269	0.077*
H18	0.2154	0.5245	0.8924	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.0533 (2)	0.0505 (2)	0.0476 (2)	0.0109 (1)	0.0248 (1)	0.0051 (1)
Sn2	0.0523 (2)	0.0489 (2)	0.0461 (2)	0.0056 (1)	0.0252 (1)	0.0048 (1)
O1	0.064 (2)	0.066 (2)	0.058 (2)	0.013 (1)	0.036 (1)	0.014 (1)
O2	0.073 (2)	0.066 (2)	0.067 (2)	0.015 (2)	0.034 (2)	0.009 (2)
O3	0.132 (3)	0.128 (3)	0.080 (2)	0.060 (3)	0.078 (2)	0.043 (2)
O4	0.132 (3)	0.100 (3)	0.102 (3)	0.058 (3)	0.087 (3)	0.032 (2)
O5	0.055 (2)	0.053 (2)	0.051 (2)	0.015 (1)	0.029 (1)	0.011 (1)
C1	0.107 (4)	0.063 (3)	0.075 (3)	0.001 (3)	0.022 (3)	−0.013 (3)
C2	0.055 (3)	0.102 (4)	0.075 (3)	−0.007 (3)	0.027 (2)	0.001 (3)
C3	0.060 (3)	0.076 (3)	0.096 (4)	−0.010 (2)	0.028 (3)	0.001 (3)
C4	0.093 (4)	0.075 (3)	0.069 (3)	0.002 (3)	0.017 (3)	−0.014 (3)
C5	0.061 (2)	0.052 (2)	0.050 (2)	−0.004 (2)	0.023 (2)	−0.002 (2)
C6	0.066 (3)	0.056 (2)	0.050 (2)	−0.014 (2)	0.027 (2)	−0.004 (2)
C7	0.086 (4)	0.101 (4)	0.072 (3)	0.009 (3)	0.048 (3)	0.014 (3)
C8	0.098 (4)	0.140 (6)	0.097 (4)	0.001 (4)	0.066 (4)	0.005 (4)
C9	0.113 (5)	0.133 (5)	0.072 (4)	−0.046 (4)	0.057 (4)	−0.014 (4)
C10	0.121 (5)	0.102 (4)	0.061 (3)	−0.022 (4)	0.039 (3)	0.013 (3)
C11	0.096 (4)	0.070 (3)	0.058 (3)	−0.008 (3)	0.031 (3)	0.005 (2)
C12	0.056 (2)	0.062 (3)	0.049 (2)	0.001 (2)	0.025 (2)	−0.007 (2)
C13	0.050 (2)	0.052 (2)	0.040 (2)	−0.002 (2)	0.022 (2)	−0.007 (2)
C14	0.065 (3)	0.061 (3)	0.050 (2)	0.006 (2)	0.024 (2)	0.003 (2)
C15	0.060 (3)	0.077 (3)	0.072 (3)	0.016 (2)	0.031 (2)	−0.006 (3)
C16	0.063 (3)	0.085 (3)	0.068 (3)	−0.002 (2)	0.040 (2)	−0.015 (3)
C17	0.079 (3)	0.077 (3)	0.048 (2)	0.003 (2)	0.036 (2)	0.005 (2)
C18	0.059 (2)	0.065 (3)	0.057 (2)	0.012 (2)	0.028 (2)	0.004 (2)

Geometric parameters (Å, º)

Sn1—C1	2.096 (5)	C15—C16	1.371 (6)
Sn1—C2	2.103 (5)	C16—C17	1.368 (6)
Sn1—O1	2.165 (3)	C17—C18	1.377 (5)
Sn1—O3	2.232 (3)	C1—H1a	0.9600
Sn1—O5	2.015 (2)	C1—H1b	0.9600
Sn2—C3	2.099 (5)	C1—H1c	0.9600
Sn2—C4	2.089 (5)	C2—H2a	0.9600
Sn2—O1^i	2.800 (3)	C2—H2b	0.9600
Sn2—O4	2.226 (3)	C2—H2c	0.9600
Sn2—O5	2.035 (2)	C3—H3a	0.9600
Sn2—O5^i	2.153 (2)	C3—H3b	0.9600
O1—C5	1.296 (5)	C3—H3c	0.9600
O2—C5	1.226 (5)	C4—H4a	0.9600
O3—C12	1.231 (5)	C4—H4b	0.9600
O4—C12	1.230 (5)	C4—H4c	0.9600
C5—C6	1.502 (5)	C7—H7	0.9300
C6—C7	1.361 (7)	C8—H8	0.9300
C6—C11	1.376 (6)	C9—H9	0.9300
C7—C8	1.386 (7)	C10—H10	0.9300
C8—C9	1.369 (9)	C11—H11	0.9300
C9—C10	1.365 (9)	C14—H14	0.9300
C10—C11	1.370 (7)	C15—H15	0.9300
C12—C13	1.495 (5)	C16—H16	0.9300
C13—C18	1.374 (5)	C17—H17	0.9300
C13—C14	1.388 (6)	C18—H18	0.9300
C14—C15	1.372 (6)
C1—Sn1—C2	139.4 (2)	C16—C15—C14	120.4 (4)
C1—Sn1—O1	96.7 (2)	C17—C16—C15	119.9 (4)
C1—Sn1—O3	86.3 (2)	C16—C17—C18	120.1 (4)
C1—Sn1—O5	109.2 (2)	C13—C18—C17	120.6 (4)
C2—Sn1—O1	97.0 (2)	Sn1—C1—H1a	109.5
C2—Sn1—O3	86.0 (2)	Sn1—C1—H1b	109.5
C2—Sn1—O5	110.7 (2)	H1a—C1—H1b	109.5
O1—Sn1—O3	171.0 (1)	Sn1—C1—H1c	109.5
O1—Sn1—O5	80.6 (1)	H1a—C1—H1c	109.5
O3—Sn1—O5	90.4 (1)	H1b—C1—H1c	109.5
C3—Sn2—C4	145.6 (2)	Sn1—C2—H2a	109.5
C3—Sn2—O1^i	78.8 (2)	Sn1—C2—H2b	109.5
C3—Sn2—O4	87.0 (2)	H2a—C2—H2b	109.5
C3—Sn2—O5	106.6 (2)	Sn1—C2—H2c	109.5
C3—Sn2—O5^i	96.3 (2)	H2a—C2—H2c	109.5
C4—Sn2—O1^i	78.3 (2)	H2b—C2—H2c	109.5
C4—Sn2—O4	85.8 (2)	Sn2—C3—H3a	109.5
C4—Sn2—O5	107.4 (2)	Sn2—C3—H3b	109.5
C4—Sn2—O5^i	96.6 (2)	H3a—C3—H3b	109.5
O1^i—Sn2—O4	125.5 (1)	Sn2—C3—H3c	109.5
O1^i—Sn2—O5	141.3 (1)	H3a—C3—H3c	109.5
O1^i—Sn2—O5^i	64.7 (1)	H3b—C3—H3c	109.5
O4—Sn2—O5	93.2 (1)	Sn2—C4—H4a	109.5
O4—Sn2—O5^i	169.8 (1)	Sn2—C4—H4b	109.5
O5—Sn2—O5^i	76.6 (1)	H4a—C4—H4b	109.5
C5—O1—Sn1	110.0 (2)	Sn2—C4—H4c	109.5
C12—O3—Sn1	140.8 (3)	H4a—C4—H4c	109.5
C12—O4—Sn2	135.9 (3)	H4b—C4—H4c	109.5
Sn1—O5—Sn2	135.2 (1)	C6—C7—H7	119.2
Sn1—O5—Sn2^i	121.4 (1)	C8—C7—H7	119.2
Sn2—O5—Sn2^i	103.4 (1)	C9—C8—H8	120.7
O2—C5—O1	121.3 (4)	C7—C8—H8	120.7
O2—C5—C6	121.9 (4)	C10—C9—H9	119.5
O1—C5—C6	116.8 (4)	C8—C9—H9	119.5
C7—C6—C11	118.4 (4)	C9—C10—H10	120.3
C7—C6—C5	122.2 (4)	C11—C10—H10	120.3
C11—C6—C5	119.4 (4)	C10—C11—H11	119.4
C6—C7—C8	121.5 (5)	C6—C11—H11	119.4
C9—C8—C7	118.5 (6)	C15—C14—H14	119.9
C10—C9—C8	121.0 (5)	C13—C14—H14	119.9
C9—C10—C11	119.3 (6)	C16—C15—H15	119.8
C10—C11—C6	121.2 (5)	C14—C15—H15	119.8
O4—C12—O3	124.3 (4)	C17—C16—H16	120.1
O4—C12—C13	117.8 (4)	C15—C16—H16	120.1
O3—C12—C13	117.9 (4)	C16—C17—H17	120.0
C18—C13—C14	119.0 (3)	C18—C17—H17	120.0
C18—C13—C12	121.1 (4)	C13—C18—H18	119.7
C14—C13—C12	120.0 (4)	C17—C18—H18	119.7
C15—C14—C13	120.1 (4)
O5—Sn1—O1—C5	178.5 (3)	Sn1—O1—C5—C6	178.7 (3)
C1—Sn1—O1—C5	−73.1 (3)	O2—C5—C6—C7	169.9 (5)
C2—Sn1—O1—C5	68.6 (3)	O1—C5—C6—C7	−9.6 (6)
O5—Sn1—O3—C12	5.3 (6)	O2—C5—C6—C11	−9.2 (6)
C1—Sn1—O3—C12	−103.9 (6)	O1—C5—C6—C11	171.3 (4)
C2—Sn1—O3—C12	116.0 (6)	C11—C6—C7—C8	−1.0 (8)
O5—Sn2—O4—C12	−0.7 (6)	C5—C6—C7—C8	179.9 (5)
C4—Sn2—O4—C12	106.5 (6)	C6—C7—C8—C9	1.6 (9)
C3—Sn2—O4—C12	−107.2 (6)	C7—C8—C9—C10	−2 (1)
O5^i—Sn2—O4—C12	2 (1)	C8—C9—C10—C11	1.7 (9)
O1^i—Sn2—O4—C12	178.9 (5)	C9—C10—C11—C6	−1.0 (8)
C1—Sn1—O5—Sn2	86.2 (3)	C7—C6—C11—C10	0.6 (7)
C2—Sn1—O5—Sn2	−85.9 (2)	C5—C6—C11—C10	179.8 (4)
O1—Sn1—O5—Sn2	−179.9 (2)	Sn2—O4—C12—O3	4.8 (9)
O3—Sn1—O5—Sn2	0.0 (2)	Sn2—O4—C12—C13	−174.7 (3)
C1—Sn1—O5—Sn2^i	−94.5 (2)	Sn1—O3—C12—O4	−8.1 (9)
C2—Sn1—O5—Sn2^i	93.4 (2)	Sn1—O3—C12—C13	171.5 (4)
O1—Sn1—O5—Sn2^i	−0.6 (1)	O4—C12—C13—C18	4.0 (6)
O3—Sn1—O5—Sn2^i	179.3 (2)	O3—C12—C13—C18	−175.6 (4)
C4—Sn2—O5—Sn1	−87.7 (3)	O4—C12—C13—C14	−175.2 (4)
C3—Sn2—O5—Sn1	86.7 (2)	O3—C12—C13—C14	5.3 (6)
O5^i—Sn2—O5—Sn1	179.4 (3)	C18—C13—C14—C15	−0.1 (6)
O4—Sn2—O5—Sn1	−1.1 (2)	C12—C13—C14—C15	179.0 (4)
O1^i—Sn2—O5—Sn1	179.4 (1)	C13—C14—C15—C16	1.1 (7)
C4—Sn2—O5—Sn2^i	92.9 (2)	C14—C15—C16—C17	−1.2 (7)
C3—Sn2—O5—Sn2^i	−92.7 (2)	C15—C16—C17—C18	0.2 (7)
O5^i—Sn2—O5—Sn2^i	0.0	C14—C13—C18—C17	−0.8 (6)
O4—Sn2—O5—Sn2^i	179.5 (2)	C12—C13—C18—C17	−180.0 (4)
O1^i—Sn2—O5—Sn2^i	0.0 (2)	C16—C17—C18—C13	0.8 (7)
Sn1—O1—C5—O2	−0.8 (5)

Symmetry code: (i) −x+1, −y+1, −z+1.