Di­chloro­bis(3,5-di­methyl­pyrazole-N²)methyl­phenyl­tin(IV)

The title compound, [SnCl₂(CH₃)(C₆H₅)(C₅H₈N₂)₂], was obtained by reaction of di­chloro­methyl­phenyl­tin(IV) and 3,5-di­methyl­pyrazole (dmpz) in chloro­form, and was recrystallized from acetone. The structure consists of octahedral all-trans [SnMePhCl₂(dmpz)₂] mol­ecules, with the Sn atom coordinated to two C [Sn-C 2.127 (5) and 2.135 (4) Å], two Cl [Sn-Cl 2.5753 (8) Å] and two N atoms [Sn-N 2.357 (3) Å]. The dmpz ligands, bound to the metal through their unprotonated N atoms, form weak intra- and intermolecular hydrogen bonds with the Cl ligands via their NH groups, giving rise to a polymeric chain along the c axis.

S1. Comment

Although the coordination chemistry of [SnMe₂]²⁺ and [SnPh₂]²⁺ derivatives has received some attention from a structural point of view, few structural studies have been carried out on compounds containing the mixed organometallic ion [SnMePh]²⁺. In fact, a survey of the Cambridge Structural Database (Allen & Kennard, 1993) showed X-ray structures for only five such compounds: two complexes with ligands coordinating via deprotonated –SH groups (Drager, 1985; Doidge-Harrison et al., 1996), [SnMePhCl₂] (Amini et al., 1987) and two adducts of the latter, [SnMePhCl₂(H₂O)]₂.18-crown-6 (Amini et al., 1994) and [SnMePhCl₂(phen)] (Buntine et al., 1998). As part of our work on structural and biological aspects of dihalodiorganotin(IV) derivatives we have prepared some new complexes of [SnMePhCl₂], one of which, [SnMePhCl₂(dmpz)₂], (I), was studied by X-ray diffraction. Fig. 1 shows the crystal structure of (I) and the atom-numbering scheme used. Selected interatomic distances and angles are listed in Table 1. \sch

The C1, Sn1, C11 and C14 atoms lie on a crystallographic twofold axis of symmetry. The Sn atom is six-coordinated in a slightly distorted all-trans octahedral environment [C11–Sn1–C1 = 180.0, Cl1–Sn1–Cl1ⁱ = 178.24 (4) and N1–Sn–N1ⁱ = 179.28 (14)°; symmetry code i = −x, y, 1/2 − z]. The Sn–C_Ph bond length [Sn1–C11 = 2.135 (4) Å] and Sn–C_Me [Sn1—C1 = 2.127 (5) Å] are similar to those found in the other two SnMePhCl₂ adducts that have been described, [SnMePhCl₂(H₂O)]₂.18-crown-6 [Sn—C_Ph = 2.103 (6) Å, Sn–C_Me = 2.124 (3) Å] (Amini et al., 1994) and [SnMePhCl₂(phen)] [Sn—C_Ph = 2.146 (5) Å, Sn–C_Me = 2.130 (6) Å] (Buntine et al., 1998). The Sn1–Cl1 bond length, 2.5753 (8) Å, is significantly longer than the 2.335 (9)–2.39 (1) Å found in the free acceptor [SnMePhCl₂] (Amini et al., 1987), in which the Sn atom is basically in a tetrahedral environment; and is also slightly longer than the 2.438 (2) and 2.500 (2) Å found in [SnMePhCl₂(phen)], in which the tin atom is in a trans-C₂, cis-Cl₂N₂ octahedral environment. The greater length of Sn1–Cl1 in [SnMePhCl₂(dmpz)₂] may be due to the hydrogen bonds in which Cl1 is involved (see below). The Sn1–N1 distances, 2.357 (3) Å, are shorter than in the phenanthroline complex [2.386 (4) and 2.410 (4) Å].

The coordination of the dmpz ligand to the tin atom mainly affects the N–N distance, which is longer than in the free ligand (N–N = 1.334 Å; Smith et al., 1989). The dmpz ligands are essentially planar, their planes making angles of ±38.2 (1)° with the equatorial plane Sn1/Cl1/Cl1ⁱ/N1/N1ⁱ. These angles place the C6 methyl groups near the phenyl ring, the plane of which almost exactly bisects the Cl1–Sn1–N1 angle. This arrangement of the phenyl and pyrazole rings is stabilized by weak bifurcated intra- and intermolecular hydrogen bonds between N2 and Cl1 [N2···Cl1 3.310 (3), H2···Cl1 2.86 Å, N2–H2···Cl1 115°] and Cl1ⁱⁱ [N2···Cl1ⁱⁱ 3.342 (3), H2···Cl1ⁱⁱ 2.57 Å, N2–H2···Cl1ⁱⁱ 150°; symmetry code ii = −x, −y, −z] (see Fig 1). The intermolecular hydrogen-bonding links the molecules in a chain along the c axis. Additionally, C6, C7 and C12 are involved in weak intra- and intermolecular C–H···Cl interactions as listed in Table 2.

It is worth comparing [SnMePhCl₂(dmpz)₂] with [SnMe₂Cl₂(dmpz)₂] (Graziani et al., 1982). In both compounds, the Sn atoms lie at a special position on a C2 symmetry axis with two independent Sn–C bonds, and the two Sn–Cl and Sn–N bond lengths are identical. However, in keeping with the expected greater Lewis acidity of the methylphenyltin(IV) unit, Sn–Cl and Sn–N are slightly shorter in [SnMePhCl₂(dmpz)₂]. The presence of the phenyl group also slightly modifies the angle between each dimethylpyrazole ring and the equatorial plane, which in [SnMe₂Cl₂(dmpz)₂] is 33.3°, and elongates the N2–H2···Cl1 hydrogen bond and all the intermolecular interactions.

S2. Experimental

Dichloromethylphenyltin(IV) was prepared by reaction of trichlorophenyltin(IV) and tetramethyltin(IV) using a published method (Kuivila et al., 1968). The complex [SnMePhCl₂(dmpz)₂] was obtained by reacting dmpz (0.068 g, 0.71 mmol) with SnMePhCl₂ (0.1 g, 0.35 mmol) dissolved in chloroform (2 ml). The white solid formed after a few minutes of stirring was recrystallized from acetone, affording crystals suitable for X-ray diffraction (m.p. 457–458 K). Analysis calculated for C₁₇H₂₄N₄Cl₂Sn: C 43.1, H 5.1, N 11.8%; found: C 43.2, H 4.6, N 11.8%. The same compound was obtained when the reactants were used in 1:1 mole ratio. The main metalated ions in the EI mass spectrum were at m/z (%) 293 (SnPhMePz, 7.2), 282 (SnMePhCl₂, 0.8), 267 (SnPhCl₂, 7.7) (base peak, CH₃COCH₃). NMR (Bruker AMX 300, CDCl₃, δ in p.p.m.): ¹H, 7.64 (m, o-Ph), 7.45 (m, m-Ph, p-Ph), 5.88 (s, C₄H), 4.38 (sb, NH), 2.27 (s, CH₃), 1.36 (s, SnCH₃, ²J(^119/117Sn-¹H) = 85.5/81.8 Hz; ¹³C, 144.9 (C3, C5), 136.2 (C_ipso - Ph), 135.2 (C_o - Ph), 131.0 (C_p - Ph), 129.5 (C_m - Ph), 105.5 (C4), 12.4 (CH₃), 10.5 (SnCH₃). IR (Raman) spectra (cm⁻¹): 3297 s, ν(N–H); 531w (534 s), ν(Sn–C_Me); 286 s (286w) ν(Sn–C_Ph); 249 s (256 s), ν(Sn–Cl).

S3. Refinement

Hydrogen atoms were introduced in calculated positions and refined using a riding model (HFIX 43 for aromatic H, and HFIX 137 for methyl H). The hydrogen atoms attached to C1 were included with occupancy factors of 0.5.

Computing details

Data collection: CAD-4 EXPRESS Software (Nonius, 1994); cell refinement: CAD-4 EXPRESS Software; data reduction: HELENA (Spek, 1993); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP (Zolsnai & Huttner, 1997); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. The crystal structure of [SnMePhCl2(dmpz)2] with the atom-numbering scheme. Atoms are represented as displacement ellipsoids drawn at the 30% probability level.

(I)

Crystal data

[SnCl2(CH3)(C6H5)(C5H8N2)2]	Dx = 1.571 Mg m^−3
Mr = 473.99	Melting point: 457 K
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 15.590 (2) Å	Cell parameters from 25 reflections
b = 10.889 (2) Å	θ = 17.6–36.4°
c = 11.870 (1) Å	µ = 1.55 mm^−1
β = 95.982 (10)°	T = 293 K
V = 2004.1 (5) Å^3	Prism, colourless
Z = 4	0.25 × 0.25 × 0.15 mm
F(000) = 952

Data collection

Enraf Nonius MACH3 diffractometer	1617 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.016
Graphite monochromator	θmax = 26.3°, θmin = 2.6°
ω scans	h = −19→19
Absorption correction: ψ-scan (north et al., 1968) ?	k = −13→0
Tmin = 0.698, Tmax = 0.801	l = −14→0
2131 measured reflections	3 standard reflections every 120 min
2028 independent reflections	intensity decay: <1%

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)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.063	H-atom parameters constrained
S = 1.02	Calculated w = 1/[σ^2(Fo^2) + (0.0211P)^2 + 1.9268P] where P = (Fo^2 + 2Fc^2)/3
2028 reflections	(Δ/σ)max < 0.001
114 parameters	Δρmax = 0.38 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

Experimental. '(North et al. 1968)'

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)
Sn1	0.0000	0.16014 (3)	0.2500	0.03192 (10)
Cl1	−0.05689 (5)	0.15652 (9)	0.03840 (6)	0.0462 (2)
C1	0.0000	−0.0352 (4)	0.2500	0.0511 (13)
H1A	−0.0409	−0.0646	0.2988	0.077*	0.50
H1B	0.0565	−0.0646	0.2768	0.077*	0.50
H1C	−0.0156	−0.0646	0.1744	0.077*	0.50
N1	0.13773 (16)	0.1588 (3)	0.1848 (2)	0.0404 (6)
N2	0.15010 (17)	0.0881 (3)	0.0931 (2)	0.0409 (7)
H2	0.1100	0.0457	0.0560	0.049*
C3	0.2313 (2)	0.0920 (3)	0.0675 (3)	0.0440 (8)
C4	0.2740 (2)	0.1671 (4)	0.1463 (3)	0.0547 (9)
H4	0.3322	0.1875	0.1512	0.066*
C5	0.2152 (2)	0.2074 (3)	0.2178 (3)	0.0415 (8)
C6	0.2280 (3)	0.2935 (4)	0.3163 (3)	0.0609 (11)
H6A	0.2038	0.3721	0.2946	0.091*
H6B	0.2885	0.3024	0.3394	0.091*
H6C	0.1998	0.2612	0.3780	0.091*
C7	0.2610 (3)	0.0230 (4)	−0.0297 (4)	0.0665 (12)
H7A	0.2567	−0.0636	−0.0161	0.100*
H7B	0.3199	0.0439	−0.0376	0.100*
H7C	0.2255	0.0441	−0.0979	0.100*
C11	0.0000	0.3563 (4)	0.2500	0.0329 (10)
C12	0.0270 (2)	0.4211 (3)	0.1598 (3)	0.0436 (8)
H12	0.0451	0.3788	0.0984	0.052*
C13	0.0275 (2)	0.5477 (3)	0.1598 (4)	0.0540 (10)
H13	0.0463	0.5904	0.0991	0.065*
C14	0.0000	0.6109 (5)	0.2500	0.0584 (16)
H14	0.0000	0.6963	0.2500	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.04015 (18)	0.02860 (16)	0.02741 (16)	0.000	0.00539 (12)	0.000
Cl1	0.0573 (5)	0.0467 (5)	0.0332 (4)	−0.0007 (4)	−0.0014 (4)	−0.0070 (4)
C1	0.078 (4)	0.028 (3)	0.050 (3)	0.000	0.023 (3)	0.000
N1	0.0421 (14)	0.0448 (15)	0.0351 (14)	−0.0031 (14)	0.0077 (11)	−0.0057 (14)
N2	0.0414 (16)	0.0420 (16)	0.0404 (16)	−0.0029 (13)	0.0088 (13)	−0.0089 (13)
C3	0.047 (2)	0.0356 (19)	0.052 (2)	0.0027 (16)	0.0167 (17)	0.0049 (17)
C4	0.0350 (17)	0.059 (2)	0.071 (3)	−0.0023 (19)	0.0077 (17)	0.012 (2)
C5	0.0442 (19)	0.0370 (17)	0.0421 (19)	−0.0055 (15)	−0.0017 (15)	0.0064 (15)
C6	0.067 (3)	0.062 (2)	0.052 (2)	−0.021 (2)	−0.002 (2)	−0.005 (2)
C7	0.077 (3)	0.057 (3)	0.073 (3)	0.010 (2)	0.044 (2)	0.002 (2)
C11	0.036 (2)	0.030 (2)	0.032 (2)	0.000	−0.0009 (18)	0.000
C12	0.050 (2)	0.0407 (19)	0.040 (2)	−0.0004 (16)	0.0052 (16)	0.0037 (16)
C13	0.054 (2)	0.042 (2)	0.065 (3)	−0.0053 (17)	0.005 (2)	0.0161 (19)
C14	0.051 (3)	0.028 (2)	0.093 (5)	0.000	−0.008 (3)	0.000

Geometric parameters (Å, º)

Sn1—C1	2.127 (5)	C4—H4	0.9300
Sn1—C11	2.135 (4)	C5—C6	1.495 (5)
Sn1—N1^i	2.357 (3)	C6—H6A	0.9600
Sn1—N1	2.357 (3)	C6—H6B	0.9600
Sn1—Cl1	2.5753 (8)	C6—H6C	0.9600
Sn1—Cl1^i	2.5753 (8)	C7—H7A	0.9600
C1—H1A	0.9600	C7—H7B	0.9600
C1—H1B	0.9600	C7—H7C	0.9600
C1—H1C	0.9600	C11—C12^i	1.385 (4)
N1—C5	1.339 (4)	C11—C12	1.385 (4)
N1—N2	1.363 (4)	C12—C13	1.378 (5)
N2—C3	1.334 (4)	C12—H12	0.9300
N2—H2	0.8600	C13—C14	1.378 (5)
C3—C4	1.363 (5)	C13—H13	0.9300
C3—C7	1.490 (5)	C14—C13^i	1.378 (5)
C4—C5	1.384 (5)	C14—H14	0.9300
C1—Sn1—C11	180.0	C3—C4—C5	107.7 (3)
C1—Sn1—N1^i	89.64 (7)	C3—C4—H4	126.2
C11—Sn1—N1^i	90.36 (7)	C5—C4—H4	126.2
C1—Sn1—N1	89.64 (7)	N1—C5—C4	109.3 (3)
C11—Sn1—N1	90.36 (7)	N1—C5—C6	121.3 (3)
N1^i—Sn1—N1	179.28 (14)	C4—C5—C6	129.4 (3)
C1—Sn1—Cl1	89.12 (2)	C5—C6—H6A	109.5
C11—Sn1—Cl1	90.88 (2)	C5—C6—H6B	109.5
N1^i—Sn1—Cl1	95.00 (7)	H6A—C6—H6B	109.5
N1—Sn1—Cl1	84.99 (7)	C5—C6—H6C	109.5
C1—Sn1—Cl1^i	89.12 (2)	H6A—C6—H6C	109.5
C11—Sn1—Cl1^i	90.88 (2)	H6B—C6—H6C	109.5
N1^i—Sn1—Cl1^i	84.99 (7)	C3—C7—H7A	109.5
N1—Sn1—Cl1^i	95.00 (7)	C3—C7—H7B	109.5
Cl1—Sn1—Cl1^i	178.24 (4)	H7A—C7—H7B	109.5
Sn1—C1—H1A	109.5	C3—C7—H7C	109.5
Sn1—C1—H1B	109.5	H7A—C7—H7C	109.5
H1A—C1—H1B	109.5	H7B—C7—H7C	109.5
Sn1—C1—H1C	109.5	C12^i—C11—C12	118.7 (4)
H1A—C1—H1C	109.5	C12^i—C11—Sn1	120.7 (2)
H1B—C1—H1C	109.5	C12—C11—Sn1	120.7 (2)
C5—N1—N2	105.0 (3)	C13—C12—C11	120.8 (4)
C5—N1—Sn1	136.6 (2)	C13—C12—H12	119.6
N2—N1—Sn1	118.37 (19)	C11—C12—H12	119.6
C3—N2—N1	112.4 (3)	C14—C13—C12	119.8 (4)
C3—N2—H2	123.8	C14—C13—H13	120.1
N1—N2—H2	123.8	C12—C13—H13	120.1
N2—C3—C4	105.6 (3)	C13—C14—C13^i	120.1 (5)
N2—C3—C7	122.7 (3)	C13—C14—H14	119.9
C4—C3—C7	131.7 (3)	C13^i—C14—H14	119.9
C1—Sn1—N1—C5	−125.5 (3)	N2—N1—C5—C6	178.9 (3)
C11—Sn1—N1—C5	54.5 (3)	Sn1—N1—C5—C6	−4.8 (5)
N1^i—Sn1—N1—C5	−125.5 (3)	C3—C4—C5—N1	0.1 (4)
Cl1—Sn1—N1—C5	145.3 (3)	C3—C4—C5—C6	−178.3 (4)
Cl1^i—Sn1—N1—C5	−36.5 (3)	C1—Sn1—C11—C12^i	63 (100)
C1—Sn1—N1—N2	50.3 (2)	N1^i—Sn1—C11—C12^i	44.36 (18)
C11—Sn1—N1—N2	−129.7 (2)	N1—Sn1—C11—C12^i	−135.64 (18)
N1^i—Sn1—N1—N2	50.3 (2)	Cl1—Sn1—C11—C12^i	139.36 (17)
Cl1—Sn1—N1—N2	−38.8 (2)	Cl1^i—Sn1—C11—C12^i	−40.64 (17)
Cl1^i—Sn1—N1—N2	139.4 (2)	C1—Sn1—C11—C12	−117 (100)
C5—N1—N2—C3	−0.7 (4)	N1^i—Sn1—C11—C12	−135.64 (18)
Sn1—N1—N2—C3	−177.8 (2)	N1—Sn1—C11—C12	44.36 (18)
N1—N2—C3—C4	0.8 (4)	Cl1—Sn1—C11—C12	−40.64 (17)
N1—N2—C3—C7	−179.7 (3)	Cl1^i—Sn1—C11—C12	139.36 (17)
N2—C3—C4—C5	−0.5 (4)	C12^i—C11—C12—C13	0.3 (3)
C7—C3—C4—C5	180.0 (4)	Sn1—C11—C12—C13	−179.7 (3)
N2—N1—C5—C4	0.3 (4)	C11—C12—C13—C14	−0.6 (5)
Sn1—N1—C5—C4	176.6 (3)	C12—C13—C14—C13^i	0.3 (3)

Symmetry code: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12···N1	0.93	2.93	3.335 (4)	108
C12—H12···Cl1	0.93	2.94	3.420 (4)	113
N2—H2···Cl1	0.86	2.86	3.310 (3)	115
C6—H6C···Cl1^i	0.96	2.78	3.643 (4)	151
N2—H2···Cl1^ii	0.86	2.57	3.342 (3)	150
C7—H7A···Cl1^ii	0.96	3.26	3.726 (4)	112

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