Enanti­omerically pure and racemic dimeth­yl{N-[(2-oxidonaphthalen-1-yl-κO)methyl­idene]­valinato-κ²N,O}tin(IV)

The title compound, [Sn(CH₃)₂(C₁₆H₁₅NO₃)], crystallized from one reaction batch with high enanti­omeric excess as both a pure enanti­omer and a racemate. The S enanti­omer crystallizes in the chiral space group P3₂. The racemate crystallizes in the space group P with R and S enanti­omers in the crystal lattice; these form dimers about a crystallographic inversion centre.

S1. Comment

Organotin(IV) complexes with O,N,O'-tridentate Schiff base ligands have received attention due to their biological properties, particularly possible antitumor activities (Nath et al., 1997; Basu Baul et al., 2001; Al-Allaf et al., 2003; Zamudio-Rivera et al., 2005; Tian et al., 2006; Beltrán et al., 2007; Kobakhidze et al., 2010). Diorganotin complexes of N-(2-hydroxyarylidene)-α-amino acids have been prepared by severel groups (Dakternieks et al., 1998; Basu Baul et al., 1999, 2005; Wang et al., 1992; Smith et al., 1992; Beltrán et al., 2003; Yin et al., 2004). We have synthesized such complexes in connection with our investigations of the syntheses and structural properties of chiral silicon and tin complexes with O,N,O'-tridentate ligands (Warncke et al., 2012; Böhme et al., 2006).

Dimethyl{N-[(2-oxidonaphthalen-1-yl-κO)methylidene]valinato-κ²N,O}tin(IV) was prepared from enantiomerically pure (S)-N-[(2-hydroxynaphthalen-1-yl)methylidene]valine and dichloridodimethyltin in the presence of triethylamine. After work-up of the reaction mixture and recrystallization (see Experimental), two different crystal types were observed under the microscope. Pale-yellow needles were characterized as enantiomerically pure crystals, (I), in the space group P3₂. Some yellow prisms were found between the surface of the solvent and the glass wall of the Schlenk tube. These were identified as the racemate, (II), of the same compound in the space group P1. The valinate ligand used for the synthesis was the pure S enantiomer. Therefore, the formation of enantiomerically pure compound (I) was expected. The bulk material of the tin complex shows a large value for the optical rotation (see Experimental) which hints at the formation of an enantiomerically pure product. The formation of the racemate was surprising and is not easy to detect. Only a small number of crystals of the racemate could be found under the microscope (estimated to be less than 5% of the overal yield of crystalline product). We assume that a small portion of the ligand was racemized during the complex formation. The mechanism of such a racemization reaction has been investigated recently (Warncke et al., 2012). Only careful examination of the crystalline product under a microscope allowed the identification of the racemate.

Fig. 1 shows the molecular structure of (I) and selected bond lengths and angles are listed in Table 1. The presence of the S form of the enantiomeric pure compound was established by anomalous dispersion effects in diffraction measurements on the crystal. The Flack (1983) parameter of the final refinement has a value of -0.02 (1). The bond lengths at the Sn atom are comparable with the bond lengths of the only known tin complex with an N-hydroxynapthylideneamino acid ligand (Smith et al., 1996). The Sn atom in (I) is pentacoordinated with three bonds to the O,N,O'-tridentate valinate ligand and two bonds to methyl groups. The coordination geometry about the Sn atom is characterized by the Addison parameter τ (Addison et al., 1984). The value of τ is 0.44, which is almost half-way between the values which define a square pyramid and a trigonal bipyramid. An alternative description of pentacoordinated geometries is provided by Holmes who uses an idealized trans-basal angle of 150° for a square pyramid (Holmes, 1984). According to this description, the Sn atom in (I) is 34.4% along the Berry pseudorotation coordinate from a trigonal bipyramid to a square pyramid.

The R and the S isomers are present in centrosymmetric crystal structure (II). The same labelling scheme as in (I) has been used for the atoms of (II). Selected bond lengths and angles are listed in Table 2. The main difference to the structure (I) is the formation of dimers in the crystal lattice. Fig. 2 shows the dimer of (II) which is formed between two Sn1—O2 units. A crystallographic inversion centre is located at the centre of the dimeric unit [Sn1···O2ⁱ = 2.8077 (18) Å; symmetry code: (i) -x+1, -y+2, -z]. The formation of the dimer implies several structural changes in comparison to (I). These are mainly an enlarged C17—Sn—C18 angle and elongated bonds involving the Sn atom. These geometrical changes lead to a lower τ value of 1/4, i.e. the square-pyramidal character is far more pronounced. Alternatively, one could consider the coordination geometry as a distorted hexacoordinated tin complex with atom O2A at a very long distance. The calculated density of (II) is higher than that of (I) (1.647 versus 1.536 Mg m ^-1). That means the crystal structures under investigation follow Wallach's rule (Wallach, 1895). However, this rule has been critically assessed recently (Brock et al., 1991). The formation of dimers might offer an explanation for the more dense packing in (II). This is quantified by the packing coefficients of 0.705 for (II) and 0.661 for (I). Not only the different densities and packing coefficients, but also the mere occurrence of the racemic by-product and its higher melting point hint to a greater stability of the racemic crystals of (II) in comparison with their chiral counterpart, (I).

Related literature

For related literature, see: Addison et al. (1984); Al-Allaf, Rashan, Stelzner & Powell (2003); Böhme et al. (2006); Basu Baul, Dutta & Tiekink (1999); Basu Baul, Dutta, Rivarola, Scopelliti & Choudhuri (2001); Basu Baul, Masharing, Willem, Biesemans, Holcapek, Jirasko & Linden (2005); Beltrán et al. (2003, 2007); Brock et al. (1991); Dakternieks et al. (1998); Flack (1983); Holmes (1984); Kobakhidze et al. (2010); Nath et al. (1997); Nitta et al. (1992); Smith et al. (1992, 1996); Tian et al. (2006); Wallach (1895); Wang et al. (1992); Warncke et al. (2012); Yin et al. (2004); Zamudio-Rivera, George-Tellez, Lopez-Mendoza, Morales-Pacheco, Flores, Höpfl, Barba, Fernandez, Cabirol & Beltrán (2005).

S2. Experimental

The ligand 2-(S)-hydroxynaphthylmethylenevaline was prepared from L-valine and 2-hydroxy-1-naphthaldehyde according to a literature method (Nitta et al., 1992). The preparation of the tin complex was performed in Schlenk tubes under argon with dry and air-free solvents.

The yellow suspension of 2-(S)-hydroxynaphthylmethylenevaline (1.26 g, 4.64 mmol) and triethylamine (1.22 g, 12.06 mmol, 30% excess) in tetrahydrofuran (50 ml) was stirred at 273 K. A solution of dichlorodimethyltin (1.02 g, 4.64 mmol) in tetrahydrofuran (10 ml) was added dropwise. A white precipitate formed and the resulting suspension was stirred 30 min at 273 K and then for 4 d at room temperature. The triethylamine hydrochloride was filtered off and washed with tetrahydrofuran (4 × 5 ml). The volatiles were removed completely from the filtrate under reduced pressure, and the residue was extracted with hot chloroform (10 ml). This CHCl₃ solution was evaporated to dryness in a vacuum and the residue was recrystallized from absolute methanol (12 ml) giving yellow crystals (yield 1.13 g, 58.2%). Analysis calculated for C₁₈H₂₁NO₃Sn: C 51.71, H 5.06, N 3.35%; found: C 51.30, H 5.11, N 3.38%.

¹¹⁹Sn NMR (CDCl₃): δ -158.3. ¹H NMR (CDCl₃): δ 0.59 (s, 3H, Sn—CH₃), 1.00 (s, 3H, Sn—CH₃), 1.08 (d, 3H, CH—CH₃, ³J_HH = 6.8 Hz), 1.11 (d, 3H, CH—CH₃, ³J_HH = 6.8 Hz), 2.39 [septet, 1H, CH(CH₃)₂, ³J_HH = 6.8 Hz], 3.97 (d, 1H, CH–COO, ³J_HH = 4,7 Hz), 6.93 (m, 1H, H_ar), 7.37 (m, 1H, H_ar), 7.57 (m, 1H, H_ar), 7.73 (m, 1H, H_ar), 7,86 (m, 1H, H_ar), 7.91 (m, 1H, H_ar), 9.03 (s, 1H, CH═N). ¹³C NMR (CDCl₃): δ -1.2, 1.7 (Sn—CH₃), 18.3, 19.1 [CH(CH₃)₂], 34.3 [CH(CH₃)₂], 74.7 (CH—COO), 108.4 (C_ar—CH═N), 118.4, 124.0, 124.6, 127.2, 129.0, 129.6, 133.9, 139.5 (8 × C_ar), 166.3 (CH═N), 172.4 (C_ar—O), 173.2 (COO). [α]²⁰_D = - 406.2° (c = 1 g per 100 ml CHCl₃). UV–VIS (c = 2.153 × 10 ^-4 mol l^-1, solvent CHCl₃): λ_max [nm] (ε, l mol^-1 cm^-1) 411 (8568), 333 (5668), 257 (17215).

S3. Refinement

In (I), similarity and rigid-bond restraints were imposed on the anisotropic displacement parameters of atoms C5 and C6. Together with the floating origin restraint for the polar space group, a total of eight restraints was used. All H atoms in both structures were positioned geometrically and refined using a riding model (including free rotation about the C—C bond for the methyl groups). The aromatic H atoms and the azomethine H atom at C11 were constrained to an ideal geometry with C—H = 0.95 Å and U_iso(H) = 1.2U_eq(C), the H atoms at tertiary C atoms C12 and C14 with C—H = 1.0 Å and U_iso(H) = 1.2U_eq(C), and the methyl H atoms with C—H = 0.98 Å and U_iso(H) = 1.5U_eq(C).

Computing details

For both compounds, data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009; data reduction: X-RED (Stoe & Cie, 2009; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

Fig. 1. The molecular structure (I), in the space group P3₂, drawn with 50% probability displacement ellipsoids.

Fig. 2. A view of the dimer of (II), in yhe space group P1, drawn with 50% probability displacement ellipsoids. The same atom numbering as in (I) was applied. [Symmetry code: (A) -x+1, -y+2, -z.]

(I) (S)-Dimethyl{N-[(2-oxidonaphthalen-1-yl- κO)methylidene]valinato-κ²N,O}tin(IV)

Crystal data

[Sn(CH3)2(C16H15NO3)]	Dx = 1.536 Mg m^−3
Mr = 418.05	Melting point: 514 K
Trigonal, P32	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 32	Cell parameters from 24695 reflections
a = 11.6246 (5) Å	θ = 2.7–29.6°
c = 11.5864 (5) Å	µ = 1.43 mm^−1
V = 1355.92 (10) Å^3	T = 200 K
Z = 3	Needle, pale yellow
F(000) = 630	0.40 × 0.18 × 0.18 mm

Data collection

Stoe IPDS 2T diffractometer	4140 independent reflections
Radiation source: fine-focus sealed tube	4082 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.053
ϕ rotation scan	θmax = 27.5°, θmin = 2.7°
Absorption correction: numerical (X-RED; Stoe & Cie, 2009	h = −15→15
Tmin = 0.599, Tmax = 0.783	k = −15→14
14770 measured reflections	l = −15→14

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.021	H-atom parameters constrained
wR(F^2) = 0.050	w = 1/[σ^2(Fo^2) + (0.0298P)^2 + 0.0805P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.002
4140 reflections	Δρmax = 0.39 e Å^−3
212 parameters	Δρmin = −1.07 e Å^−3
8 restraints	Absolute structure: Flack (1983), ???? Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.02 (1)

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
Sn1	0.886237 (14)	0.595967 (12)	−0.16285 (1)	0.02762 (5)
O1	0.73488 (18)	0.42325 (16)	−0.08351 (14)	0.0338 (3)
O2	1.05095 (17)	0.79610 (17)	−0.16180 (15)	0.0375 (4)
O3	1.1663 (2)	0.98279 (18)	−0.06267 (15)	0.0466 (5)
N1	0.86127 (18)	0.68276 (16)	−0.00860 (14)	0.0264 (3)
C1	0.6298 (2)	0.5170 (2)	0.03048 (16)	0.0273 (4)
C2	0.6328 (2)	0.4110 (2)	−0.02588 (16)	0.0282 (4)
C3	0.5200 (3)	0.2801 (2)	−0.01572 (19)	0.0362 (5)
H3	0.5228	0.2073	−0.0500	0.043*
C4	0.4097 (2)	0.2582 (3)	0.0415 (2)	0.0399 (5)
H4	0.3369	0.1701	0.0469	0.048*
C5	0.2813 (3)	0.3412 (3)	0.1507 (3)	0.0520 (7)
H5	0.2084	0.2530	0.1558	0.062*
C6	0.2699 (3)	0.4430 (4)	0.1979 (3)	0.0567 (7)
H6	0.1900	0.4260	0.2350	0.068*
C7	0.3776 (3)	0.5724 (4)	0.1907 (3)	0.0520 (7)
H7	0.3698	0.6435	0.2226	0.062*
C8	0.4951 (3)	0.5991 (3)	0.1383 (2)	0.0386 (5)
H8	0.5670	0.6879	0.1354	0.046*
C9	0.5095 (2)	0.4951 (2)	0.08858 (17)	0.0314 (4)
C10	0.3995 (2)	0.3642 (3)	0.09440 (19)	0.0367 (5)
C11	0.7497 (2)	0.6421 (2)	0.04594 (16)	0.0265 (4)
H11	0.7473	0.7010	0.1015	0.032*
C12	0.9770 (2)	0.8071 (2)	0.03020 (16)	0.0280 (4)
H12	0.9458	0.8697	0.0540	0.034*
C13	1.0736 (2)	0.8695 (2)	−0.07085 (17)	0.0302 (4)
C14	1.0413 (2)	0.7804 (2)	0.1363 (2)	0.0377 (6)
H14	0.9677	0.7298	0.1926	0.045*
C15	1.0994 (4)	0.6931 (4)	0.1093 (3)	0.0578 (8)
H15A	1.1763	0.7409	0.0583	0.087*
H15B	1.0323	0.6120	0.0709	0.087*
H15C	1.1275	0.6698	0.1811	0.087*
C16	1.1405 (3)	0.9077 (3)	0.1973 (2)	0.0556 (8)
H16A	1.1693	0.8857	0.2694	0.083*
H16B	1.0985	0.9608	0.2146	0.083*
H16C	1.2177	0.9587	0.1473	0.083*
C17	0.7717 (3)	0.6180 (3)	−0.2926 (2)	0.0473 (6)
H17A	0.8234	0.7057	−0.3286	0.071*
H17B	0.6908	0.6098	−0.2585	0.071*
H17C	0.7476	0.5489	−0.3512	0.071*
C18	1.0119 (3)	0.5152 (3)	−0.1816 (2)	0.0448 (5)
H18A	0.9731	0.4422	−0.2375	0.067*
H18B	1.0218	0.4815	−0.1069	0.067*
H18C	1.0991	0.5842	−0.2091	0.067*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.03397 (8)	0.02429 (7)	0.02250 (6)	0.01298 (6)	−0.00173 (5)	−0.00211 (4)
O1	0.0384 (9)	0.0227 (7)	0.0362 (7)	0.0123 (6)	−0.0018 (6)	−0.0021 (6)
O2	0.0390 (9)	0.0311 (8)	0.0285 (8)	0.0070 (7)	0.0065 (6)	−0.0002 (6)
O3	0.0460 (10)	0.0277 (8)	0.0385 (9)	−0.0022 (7)	0.0099 (7)	0.0010 (7)
N1	0.0281 (8)	0.0207 (8)	0.0222 (7)	0.0061 (7)	−0.0006 (6)	−0.0023 (6)
C1	0.0254 (9)	0.0245 (9)	0.0240 (8)	0.0064 (8)	−0.0039 (7)	0.0018 (7)
C2	0.0306 (10)	0.0209 (9)	0.0246 (8)	0.0064 (8)	−0.0076 (7)	0.0013 (7)
C3	0.0413 (12)	0.0212 (10)	0.0319 (9)	0.0051 (9)	−0.0107 (8)	0.0009 (7)
C4	0.0350 (12)	0.0282 (10)	0.0354 (10)	−0.0001 (9)	−0.0097 (9)	0.0063 (9)
C5	0.0284 (12)	0.0583 (17)	0.0453 (13)	0.0038 (11)	0.0026 (10)	0.0132 (12)
C6	0.0349 (13)	0.072 (2)	0.0509 (15)	0.0178 (14)	0.0097 (11)	0.0058 (14)
C7	0.0419 (15)	0.0633 (19)	0.0496 (14)	0.0253 (14)	0.0088 (11)	−0.0003 (13)
C8	0.0319 (11)	0.0373 (12)	0.0392 (11)	0.0117 (10)	0.0027 (9)	0.0010 (9)
C9	0.0269 (10)	0.0335 (11)	0.0263 (9)	0.0094 (9)	−0.0034 (7)	0.0048 (8)
C10	0.0270 (10)	0.0364 (12)	0.0320 (10)	0.0048 (9)	−0.0054 (8)	0.0074 (8)
C11	0.0284 (9)	0.0217 (9)	0.0228 (8)	0.0077 (8)	−0.0019 (7)	−0.0015 (6)
C12	0.0283 (10)	0.0220 (9)	0.0235 (8)	0.0049 (8)	0.0015 (7)	−0.0015 (7)
C13	0.0300 (10)	0.0243 (9)	0.0281 (9)	0.0074 (8)	0.0028 (7)	0.0034 (7)
C14	0.0328 (11)	0.0346 (12)	0.0262 (11)	0.0022 (9)	−0.0027 (7)	0.0016 (7)
C15	0.0634 (19)	0.066 (2)	0.0483 (15)	0.0358 (17)	−0.0152 (13)	0.0027 (14)
C16	0.0450 (15)	0.0481 (16)	0.0392 (13)	−0.0027 (13)	−0.0114 (11)	−0.0067 (11)
C17	0.0633 (17)	0.0424 (14)	0.0348 (11)	0.0253 (13)	−0.0180 (11)	−0.0002 (10)
C18	0.0469 (14)	0.0458 (14)	0.0482 (13)	0.0281 (12)	0.0038 (11)	−0.0031 (11)

Geometric parameters (Å, º)

Sn1—C18	2.106 (3)	C7—H7	0.9500
Sn1—O1	2.1070 (17)	C8—C9	1.423 (4)
Sn1—C17	2.107 (2)	C8—H8	0.9500
Sn1—N1	2.1422 (16)	C9—C10	1.418 (3)
Sn1—O2	2.1504 (17)	C11—H11	0.9500
O1—C2	1.306 (3)	C12—C13	1.531 (3)
O2—C13	1.297 (3)	C12—C14	1.549 (3)
O3—C13	1.219 (3)	C12—H12	1.0000
N1—C11	1.301 (3)	C14—C15	1.507 (4)
N1—C12	1.469 (2)	C14—C16	1.521 (3)
C1—C2	1.411 (3)	C14—H14	1.0000
C1—C11	1.436 (3)	C15—H15A	0.9800
C1—C9	1.454 (3)	C15—H15B	0.9800
C2—C3	1.433 (3)	C15—H15C	0.9800
C3—C4	1.349 (4)	C16—H16A	0.9800
C3—H3	0.9500	C16—H16B	0.9800
C4—C10	1.434 (4)	C16—H16C	0.9800
C4—H4	0.9500	C17—H17A	0.9800
C5—C6	1.369 (5)	C17—H17B	0.9800
C5—C10	1.420 (4)	C17—H17C	0.9800
C5—H5	0.9500	C18—H18A	0.9800
C6—C7	1.398 (5)	C18—H18B	0.9800
C6—H6	0.9500	C18—H18C	0.9800
C7—C8	1.380 (4)
C18—Sn1—O1	93.14 (9)	C5—C10—C4	121.5 (2)
C18—Sn1—C17	127.01 (12)	N1—C11—C1	126.44 (19)
O1—Sn1—C17	98.63 (10)	N1—C11—H11	116.8
C18—Sn1—N1	125.71 (9)	C1—C11—H11	116.8
O1—Sn1—N1	80.77 (6)	N1—C12—C13	109.02 (16)
C17—Sn1—N1	107.19 (10)	N1—C12—C14	109.99 (17)
C18—Sn1—O2	92.42 (10)	C13—C12—C14	112.89 (18)
O1—Sn1—O2	153.64 (6)	N1—C12—H12	108.3
C17—Sn1—O2	98.47 (10)	C13—C12—H12	108.3
N1—Sn1—O2	75.09 (6)	C14—C12—H12	108.3
C2—O1—Sn1	127.39 (13)	O3—C13—O2	123.55 (19)
C13—O2—Sn1	119.62 (13)	O3—C13—C12	119.69 (19)
C11—N1—C12	117.70 (17)	O2—C13—C12	116.76 (18)
C11—N1—Sn1	125.42 (14)	C15—C14—C16	112.0 (3)
C12—N1—Sn1	116.49 (13)	C15—C14—C12	113.2 (2)
C2—C1—C11	120.4 (2)	C16—C14—C12	112.4 (2)
C2—C1—C9	120.21 (19)	C15—C14—H14	106.2
C11—C1—C9	118.74 (19)	C16—C14—H14	106.2
O1—C2—C1	124.05 (18)	C12—C14—H14	106.2
O1—C2—C3	117.2 (2)	C14—C15—H15A	109.5
C1—C2—C3	118.7 (2)	C14—C15—H15B	109.5
C4—C3—C2	121.3 (2)	H15A—C15—H15B	109.5
C4—C3—H3	119.3	C14—C15—H15C	109.5
C2—C3—H3	119.3	H15A—C15—H15C	109.5
C3—C4—C10	121.8 (2)	H15B—C15—H15C	109.5
C3—C4—H4	119.1	C14—C16—H16A	109.5
C10—C4—H4	119.1	C14—C16—H16B	109.5
C6—C5—C10	121.5 (3)	H16A—C16—H16B	109.5
C6—C5—H5	119.2	C14—C16—H16C	109.5
C10—C5—H5	119.2	H16A—C16—H16C	109.5
C5—C6—C7	119.0 (3)	H16B—C16—H16C	109.5
C5—C6—H6	120.5	Sn1—C17—H17A	109.5
C7—C6—H6	120.5	Sn1—C17—H17B	109.5
C8—C7—C6	121.4 (3)	H17A—C17—H17B	109.5
C8—C7—H7	119.3	Sn1—C17—H17C	109.5
C6—C7—H7	119.3	H17A—C17—H17C	109.5
C7—C8—C9	120.7 (3)	H17B—C17—H17C	109.5
C7—C8—H8	119.6	Sn1—C18—H18A	109.5
C9—C8—H8	119.6	Sn1—C18—H18B	109.5
C10—C9—C8	117.8 (2)	H18A—C18—H18B	109.5
C10—C9—C1	118.8 (2)	Sn1—C18—H18C	109.5
C8—C9—C1	123.4 (2)	H18A—C18—H18C	109.5
C9—C10—C5	119.5 (3)	H18B—C18—H18C	109.5
C9—C10—C4	119.0 (2)
C18—Sn1—O1—C2	164.90 (17)	C2—C1—C9—C10	4.4 (3)
C17—Sn1—O1—C2	−66.93 (18)	C11—C1—C9—C10	−166.54 (18)
N1—Sn1—O1—C2	39.22 (16)	C2—C1—C9—C8	−174.2 (2)
O2—Sn1—O1—C2	63.0 (2)	C11—C1—C9—C8	14.8 (3)
C18—Sn1—O2—C13	−117.30 (19)	C8—C9—C10—C5	−1.2 (3)
O1—Sn1—O2—C13	−15.2 (3)	C1—C9—C10—C5	−179.9 (2)
C17—Sn1—O2—C13	114.72 (19)	C8—C9—C10—C4	177.9 (2)
N1—Sn1—O2—C13	9.09 (17)	C1—C9—C10—C4	−0.8 (3)
C18—Sn1—N1—C11	−120.69 (19)	C6—C5—C10—C9	1.3 (4)
O1—Sn1—N1—C11	−33.46 (17)	C6—C5—C10—C4	−177.8 (3)
C17—Sn1—N1—C11	62.8 (2)	C3—C4—C10—C9	−1.5 (3)
O2—Sn1—N1—C11	157.21 (19)	C3—C4—C10—C5	177.6 (2)
C18—Sn1—N1—C12	66.69 (18)	C12—N1—C11—C1	−172.58 (19)
O1—Sn1—N1—C12	153.92 (15)	Sn1—N1—C11—C1	14.9 (3)
C17—Sn1—N1—C12	−109.84 (17)	C2—C1—C11—N1	16.7 (3)
O2—Sn1—N1—C12	−15.41 (14)	C9—C1—C11—N1	−172.39 (19)
Sn1—O1—C2—C1	−25.0 (3)	C11—N1—C12—C13	−154.31 (19)
Sn1—O1—C2—C3	157.95 (14)	Sn1—N1—C12—C13	18.9 (2)
C11—C1—C2—O1	−11.8 (3)	C11—N1—C12—C14	81.4 (2)
C9—C1—C2—O1	177.39 (18)	Sn1—N1—C12—C14	−105.37 (17)
C11—C1—C2—C3	165.21 (18)	Sn1—O2—C13—O3	178.5 (2)
C9—C1—C2—C3	−5.6 (3)	Sn1—O2—C13—C12	−1.3 (3)
O1—C2—C3—C4	−179.5 (2)	N1—C12—C13—O3	168.9 (2)
C1—C2—C3—C4	3.3 (3)	C14—C12—C13—O3	−68.6 (3)
C2—C3—C4—C10	0.3 (3)	N1—C12—C13—O2	−11.3 (3)
C10—C5—C6—C7	−0.3 (5)	C14—C12—C13—O2	111.2 (2)
C5—C6—C7—C8	−0.7 (5)	N1—C12—C14—C15	65.2 (3)
C6—C7—C8—C9	0.7 (5)	C13—C12—C14—C15	−56.8 (3)
C7—C8—C9—C10	0.3 (4)	N1—C12—C14—C16	−166.7 (2)
C7—C8—C9—C1	178.9 (2)	C13—C12—C14—C16	71.3 (3)

(II) (RS)-Dimethyl{N-[(2-oxidonaphthalen-1-yl- κO)methylidene]valinato-κ²N,O}tin(IV)

Crystal data

[Sn(CH3)2(C16H15NO3)]	Z = 2
Mr = 418.05	F(000) = 420
Triclinic, P1	Dx = 1.647 Mg m^−3
Hall symbol: -P 1	Melting point: 566 K
a = 8.3148 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.6633 (5) Å	Cell parameters from 35193 reflections
c = 12.4320 (8) Å	θ = 1.7–29.6°
α = 71.030 (5)°	µ = 1.53 mm^−1
β = 87.440 (6)°	T = 153 K
γ = 84.553 (5)°	Prism, yellow
V = 842.97 (9) Å^3	0.40 × 0.38 × 0.31 mm

Data collection

Stoe IPDS 2 diffractometer	3859 independent reflections
Radiation source: fine-focus sealed tube	3798 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.091
ϕ rotation scan	θmax = 27.5°, θmin = 1.7°
Absorption correction: integration (X-RED; Stoe & Cie, 2009)	h = −10→10
Tmin = 0.744, Tmax = 0.866	k = −11→11
13032 measured reflections	l = −16→16

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) = 0.096	H-atom parameters constrained
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0553P)^2 + 0.5942P] where P = (Fo^2 + 2Fc^2)/3
3859 reflections	(Δ/σ)max = 0.001
212 parameters	Δρmax = 0.81 e Å^−3
0 restraints	Δρmin = −2.39 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
Sn1	0.425842 (16)	1.007258 (18)	0.165931 (12)	0.01402 (9)
O1	0.3887 (2)	1.0148 (3)	0.33583 (16)	0.0193 (4)
O2	0.3633 (2)	0.9359 (3)	0.02311 (16)	0.0184 (4)
O3	0.1818 (2)	0.8450 (3)	−0.06185 (17)	0.0222 (4)
N1	0.1792 (2)	0.9414 (3)	0.19614 (18)	0.0138 (4)
C1	0.1046 (3)	1.0973 (3)	0.3260 (2)	0.0149 (5)
C2	0.2607 (3)	1.0844 (3)	0.3716 (2)	0.0143 (4)
C3	0.2798 (3)	1.1468 (3)	0.4634 (2)	0.0181 (5)
H3	0.3819	1.1311	0.4985	0.022*
C4	0.1531 (3)	1.2282 (4)	0.5008 (2)	0.0191 (5)
H4	0.1694	1.2696	0.5611	0.023*
C5	−0.1321 (3)	1.3430 (4)	0.4897 (2)	0.0227 (5)
H5	−0.1137	1.3881	0.5478	0.027*
C6	−0.2827 (3)	1.3658 (4)	0.4438 (3)	0.0255 (6)
H6	−0.3687	1.4243	0.4709	0.031*
C7	−0.3091 (3)	1.3020 (4)	0.3562 (3)	0.0240 (6)
H7	−0.4132	1.3183	0.3238	0.029*
C8	−0.1854 (3)	1.2160 (4)	0.3168 (2)	0.0189 (5)
H8	−0.2050	1.1755	0.2566	0.023*
C9	−0.0291 (3)	1.1869 (3)	0.3646 (2)	0.0152 (5)
C10	−0.0039 (3)	1.2535 (3)	0.4521 (2)	0.0166 (5)
C11	0.0734 (3)	1.0090 (3)	0.2515 (2)	0.0140 (4)
H11	−0.0369	0.9981	0.2410	0.017*
C12	0.1171 (3)	0.8530 (3)	0.1257 (2)	0.0143 (5)
H12	0.0064	0.9039	0.1003	0.000*
C13	0.2257 (3)	0.8778 (3)	0.0196 (2)	0.0149 (5)
C14	0.1036 (3)	0.6707 (3)	0.1928 (2)	0.0183 (5)
H14	0.0343	0.6661	0.2614	0.022*
C15	0.2670 (4)	0.5801 (4)	0.2354 (3)	0.0244 (6)
H15A	0.2513	0.4672	0.2823	0.037*
H15B	0.3169	0.6356	0.2809	0.037*
H15C	0.3375	0.5792	0.1702	0.037*
C16	0.0187 (4)	0.5852 (4)	0.1240 (3)	0.0295 (6)
H16A	0.0874	0.5795	0.0590	0.044*
H16B	−0.0844	0.6471	0.0966	0.044*
H16C	−0.0010	0.4741	0.1724	0.044*
C17	0.6130 (3)	0.8205 (4)	0.2282 (2)	0.0225 (5)
H17A	0.6468	0.7714	0.1691	0.034*
H17B	0.5740	0.7362	0.2954	0.034*
H17C	0.7050	0.8671	0.2489	0.034*
C18	0.4036 (4)	1.2643 (4)	0.0897 (3)	0.0240 (6)
H18A	0.5022	1.3092	0.1025	0.036*
H18B	0.3108	1.3113	0.1235	0.036*
H18C	0.3876	1.2917	0.0078	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sn1	0.01081 (12)	0.01644 (14)	0.01635 (13)	−0.00040 (8)	−0.00060 (7)	−0.00753 (9)
O1	0.0138 (8)	0.0273 (10)	0.0185 (9)	0.0021 (7)	−0.0016 (7)	−0.0108 (8)
O2	0.0154 (8)	0.0268 (10)	0.0173 (9)	−0.0046 (7)	0.0026 (7)	−0.0128 (8)
O3	0.0226 (9)	0.0301 (11)	0.0169 (9)	−0.0034 (8)	−0.0013 (7)	−0.0113 (8)
N1	0.0105 (9)	0.0165 (10)	0.0165 (10)	−0.0015 (7)	−0.0009 (7)	−0.0081 (8)
C1	0.0152 (11)	0.0171 (12)	0.0139 (11)	−0.0033 (9)	−0.0001 (8)	−0.0065 (9)
C2	0.0137 (10)	0.0170 (12)	0.0121 (10)	−0.0016 (8)	0.0005 (8)	−0.0048 (9)
C3	0.0177 (11)	0.0242 (14)	0.0136 (11)	−0.0029 (10)	−0.0031 (9)	−0.0072 (10)
C4	0.0231 (12)	0.0215 (13)	0.0145 (11)	−0.0021 (10)	−0.0019 (9)	−0.0081 (10)
C5	0.0269 (13)	0.0239 (15)	0.0199 (12)	0.0015 (11)	0.0018 (10)	−0.0121 (11)
C6	0.0233 (13)	0.0285 (15)	0.0262 (14)	0.0048 (11)	0.0043 (11)	−0.0135 (12)
C7	0.0163 (11)	0.0295 (16)	0.0272 (14)	0.0021 (10)	0.0005 (10)	−0.0117 (12)
C8	0.0155 (11)	0.0224 (13)	0.0208 (12)	−0.0003 (9)	−0.0009 (9)	−0.0097 (10)
C9	0.0165 (11)	0.0150 (12)	0.0142 (11)	−0.0015 (9)	0.0018 (8)	−0.0051 (9)
C10	0.0199 (11)	0.0169 (12)	0.0130 (11)	−0.0019 (9)	0.0003 (9)	−0.0050 (9)
C11	0.0118 (10)	0.0176 (12)	0.0136 (11)	−0.0011 (8)	0.0001 (8)	−0.0063 (9)
C12	0.0125 (10)	0.0190 (12)	0.0142 (11)	−0.0012 (9)	−0.0016 (8)	−0.0089 (9)
C13	0.0152 (10)	0.0134 (12)	0.0164 (11)	0.0001 (9)	−0.0010 (8)	−0.0053 (9)
C14	0.0201 (11)	0.0183 (13)	0.0183 (12)	−0.0060 (10)	0.0019 (9)	−0.0077 (10)
C15	0.0282 (14)	0.0189 (14)	0.0239 (13)	−0.0003 (11)	0.0006 (11)	−0.0045 (11)
C16	0.0383 (16)	0.0252 (16)	0.0300 (15)	−0.0159 (13)	0.0000 (12)	−0.0120 (13)
C17	0.0154 (11)	0.0255 (15)	0.0235 (13)	0.0064 (10)	−0.0023 (9)	−0.0058 (11)
C18	0.0268 (13)	0.0188 (14)	0.0274 (14)	−0.0008 (10)	0.0034 (11)	−0.0094 (11)

Geometric parameters (Å, º)

Sn1—C17	2.110 (3)	C7—H7	0.9500
Sn1—C18	2.111 (3)	C8—C9	1.419 (3)
Sn1—O1	2.1421 (19)	C8—H8	0.9500
Sn1—O2	2.1593 (18)	C9—C10	1.418 (3)
Sn1—N1	2.165 (2)	C11—H11	0.9500
O1—C2	1.305 (3)	C12—C13	1.532 (3)
O2—C13	1.301 (3)	C12—C14	1.540 (4)
O3—C13	1.216 (3)	C12—H12	1.0000
N1—C11	1.304 (3)	C14—C15	1.528 (4)
N1—C12	1.474 (3)	C14—C16	1.531 (4)
C1—C2	1.420 (3)	C14—H14	1.0000
C1—C11	1.424 (3)	C15—H15A	0.9800
C1—C9	1.449 (3)	C15—H15B	0.9800
C2—C3	1.432 (3)	C15—H15C	0.9800
C3—C4	1.361 (4)	C16—H16A	0.9800
C3—H3	0.9500	C16—H16B	0.9800
C4—C10	1.431 (3)	C16—H16C	0.9800
C4—H4	0.9500	C17—H17A	0.9800
C5—C6	1.370 (4)	C17—H17B	0.9800
C5—C10	1.411 (4)	C17—H17C	0.9800
C5—H5	0.9500	C18—H18A	0.9800
C6—C7	1.405 (4)	C18—H18B	0.9800
C6—H6	0.9500	C18—H18C	0.9800
C7—C8	1.378 (4)
C17—Sn1—C18	137.42 (12)	C9—C10—C4	118.8 (2)
C17—Sn1—O1	88.14 (9)	N1—C11—C1	127.3 (2)
C18—Sn1—O1	94.58 (10)	N1—C11—H11	116.3
C17—Sn1—O2	97.03 (10)	C1—C11—H11	116.3
C18—Sn1—O2	99.54 (10)	N1—C12—C13	108.33 (19)
O1—Sn1—O2	152.46 (7)	N1—C12—C14	112.0 (2)
C17—Sn1—N1	117.83 (10)	C13—C12—C14	112.5 (2)
C18—Sn1—N1	104.43 (10)	N1—C12—H12	107.9
O1—Sn1—N1	79.92 (7)	C13—C12—H12	107.9
O2—Sn1—N1	73.74 (7)	C14—C12—H12	107.9
C2—O1—Sn1	124.92 (16)	O3—C13—O2	123.6 (2)
C13—O2—Sn1	121.47 (16)	O3—C13—C12	120.5 (2)
C11—N1—C12	117.3 (2)	O2—C13—C12	116.0 (2)
C11—N1—Sn1	122.78 (17)	C15—C14—C16	111.3 (3)
C12—N1—Sn1	117.71 (15)	C15—C14—C12	112.4 (2)
C2—C1—C11	120.8 (2)	C16—C14—C12	111.5 (2)
C2—C1—C9	119.8 (2)	C15—C14—H14	107.1
C11—C1—C9	119.0 (2)	C16—C14—H14	107.1
O1—C2—C1	123.2 (2)	C12—C14—H14	107.1
O1—C2—C3	117.7 (2)	C14—C15—H15A	109.5
C1—C2—C3	119.0 (2)	C14—C15—H15B	109.5
C4—C3—C2	120.6 (2)	H15A—C15—H15B	109.5
C4—C3—H3	119.7	C14—C15—H15C	109.5
C2—C3—H3	119.7	H15A—C15—H15C	109.5
C3—C4—C10	122.1 (2)	H15B—C15—H15C	109.5
C3—C4—H4	119.0	C14—C16—H16A	109.5
C10—C4—H4	119.0	C14—C16—H16B	109.5
C6—C5—C10	121.0 (3)	H16A—C16—H16B	109.5
C6—C5—H5	119.5	C14—C16—H16C	109.5
C10—C5—H5	119.5	H16A—C16—H16C	109.5
C5—C6—C7	119.5 (3)	H16B—C16—H16C	109.5
C5—C6—H6	120.3	Sn1—C17—H17A	109.5
C7—C6—H6	120.3	Sn1—C17—H17B	109.5
C8—C7—C6	120.6 (3)	H17A—C17—H17B	109.5
C8—C7—H7	119.7	Sn1—C17—H17C	109.5
C6—C7—H7	119.7	H17A—C17—H17C	109.5
C7—C8—C9	121.2 (2)	H17B—C17—H17C	109.5
C7—C8—H8	119.4	Sn1—C18—H18A	109.5
C9—C8—H8	119.4	Sn1—C18—H18B	109.5
C10—C9—C8	117.5 (2)	H18A—C18—H18B	109.5
C10—C9—C1	119.3 (2)	Sn1—C18—H18C	109.5
C8—C9—C1	123.1 (2)	H18A—C18—H18C	109.5
C5—C10—C9	120.1 (2)	H18B—C18—H18C	109.5
C5—C10—C4	121.1 (2)
C17—Sn1—O1—C2	−164.4 (2)	C2—C1—C9—C10	−3.3 (4)
C18—Sn1—O1—C2	58.2 (2)	C11—C1—C9—C10	170.1 (2)
O2—Sn1—O1—C2	−62.7 (3)	C2—C1—C9—C8	174.9 (2)
N1—Sn1—O1—C2	−45.7 (2)	C11—C1—C9—C8	−11.6 (4)
C17—Sn1—O2—C13	112.0 (2)	C6—C5—C10—C9	0.7 (4)
C18—Sn1—O2—C13	−107.4 (2)	C6—C5—C10—C4	−179.4 (3)
O1—Sn1—O2—C13	12.4 (3)	C8—C9—C10—C5	0.8 (4)
N1—Sn1—O2—C13	−5.0 (2)	C1—C9—C10—C5	179.2 (3)
C17—Sn1—N1—C11	121.3 (2)	C8—C9—C10—C4	−179.1 (2)
C18—Sn1—N1—C11	−53.3 (2)	C1—C9—C10—C4	−0.7 (4)
O1—Sn1—N1—C11	38.8 (2)	C3—C4—C10—C5	−177.9 (3)
O2—Sn1—N1—C11	−149.3 (2)	C3—C4—C10—C9	2.0 (4)
C17—Sn1—N1—C12	−76.0 (2)	C12—N1—C11—C1	178.7 (2)
C18—Sn1—N1—C12	109.37 (19)	Sn1—N1—C11—C1	−18.5 (4)
O1—Sn1—N1—C12	−158.45 (19)	C2—C1—C11—N1	−17.0 (4)
O2—Sn1—N1—C12	13.45 (17)	C9—C1—C11—N1	169.6 (3)
Sn1—O1—C2—C1	30.0 (4)	C11—N1—C12—C13	144.9 (2)
Sn1—O1—C2—C3	−151.56 (19)	Sn1—N1—C12—C13	−18.7 (3)
C11—C1—C2—O1	11.2 (4)	C11—N1—C12—C14	−90.4 (3)
C9—C1—C2—O1	−175.5 (2)	Sn1—N1—C12—C14	105.9 (2)
C11—C1—C2—C3	−167.2 (2)	Sn1—O2—C13—O3	175.6 (2)
C9—C1—C2—C3	6.1 (4)	Sn1—O2—C13—C12	−3.9 (3)
O1—C2—C3—C4	176.6 (3)	N1—C12—C13—O3	−165.3 (2)
C1—C2—C3—C4	−5.0 (4)	C14—C12—C13—O3	70.4 (3)
C2—C3—C4—C10	0.9 (4)	N1—C12—C13—O2	14.3 (3)
C10—C5—C6—C7	−1.4 (5)	C14—C12—C13—O2	−110.1 (3)
C5—C6—C7—C8	0.4 (5)	N1—C12—C14—C15	−61.6 (3)
C6—C7—C8—C9	1.1 (5)	C13—C12—C14—C15	60.7 (3)
C7—C8—C9—C10	−1.7 (4)	N1—C12—C14—C16	172.6 (2)
C7—C8—C9—C1	180.0 (3)	C13—C12—C14—C16	−65.1 (3)