Indian Journal of Chemistry Vol. 438, July 2004, pp. 1493- 149S

Synthesis and characterization of drum clusters hexameric benzyloxotin aromatic substituted acrylates and crystal structure of hexameric benzyloxotin cinnamate

Handong Yin*, Chuanhua Wang & Yong Wang

Department of Chemistry, Liaocheng University, Liaocheng 252059, P R China

Received 22 April 2003; accepted (re vised) 3 September 2003

The eight drum clusters hexameric benzyloxotin aromatic substituted acry lates are sy nthesized by the reaction of [(PhCH2)3SnhO with aromatic substi tuted acrylic acids in 1:2 molar ratio. The crystal structure of hexameric benzyloxotin cinnamate is determined by X-ray single crystal diffraction. The crystal belongs to triclinic with space group Pi, a= 1.6771 (3) nm, b= 1.8020(4) nm, c=2 .1 073(4) nm, a=1 OS. III (3t, ~= I 03.614(3)°, Y= I04.679(3t, 2=2, V=5.5033( IS) nm3, Dc= 1.350 g/m3, p= 1.396 mn'-', F(000)=220S, R=0.0606, wR=0.069S. The molecular structure show a distorted octahedron configuration with six coordination for the central tin atoms.

IPC: Int.CI.7 C 07 C 57/44, 57/04

Recently we have investigated the structural chemis­try of a number of di- or tri-organotin carboxylates. I.8

These studies have shown that organotin carboxylates adopt structure which is dependent on both the nature of the alkyl or ary l substituent bound to the tin atom and the type of carboxylate ligand .I.3.8. 11 We have now turned to the monoorganotin carboxylates.

Two major prototypes have been structurally char­acterized for the monoorganooxotin carboxylates,12.15 "drum" structure with general formula [RSn(O)(02CR')]6 and " ladder" arrangement with the formula {[RSn(O)(02CR')h[RSn (02CR'h] h We report herein the synthesis of eight novel drum hexameric benzyloxotin aromatic substituted acrylates (Scheme I) and X-ray crystal structure of drum hexameric benzyloxotin cinnamate. The X-ray char­acterization shows that this compound appear as a drum-shaped molecule containing six-coordinated tin atoms.

Experimental Section General procedure. IR spectra were recorded with

a Nicolet-460 spectrophotometer as KEr discs. IH NMR spectra was recorded on a Jeol-FX-90Q NMR spectrometer and referenced to Me4Si in CDCh. Elemental analyses were performed in a PE-2400Il

elemental analyzer and tin was estimated as Sn02. Synthesis of compounds 1-8. Aromatic substituted

acrylic acid (6.0 mmole) was added to a benzene solu­tion (40 mL) of [(PhCH2)3SnhO (3.0 mmole). The mixture was heated under reflux with stirring for 14 hr. The clear solution thus obtained was evaporated under vacuum to form a white solid and recrystallized in di­chloromethane-hexane to give colourless crystals.

Crystallographic measurements of hexameric benzyloxotin cinnamate. Crystal data for 1, were measured on a Bruker Smart 1000 CCD diffracto­meter equipped with graphite monochromated MoKcx ("-=0.071073 nm) radiation . The data were collected at temperature of 293(2) K to maximum e value of 26.60°. The structure was solved by direct method and expanded using Fourier techniques with Shelxl-97 program. The non-hydrogen atoms were refined anisotropically by full-matrix least-squares calcula­tions. The hydrogen atoms were added according to theoretical models. Details of data collection and structure refinement are listed in Table I .

Results and Discussion Physical properties. Physical data for compounds

1-8 are listed in Table II. All compounds are colourless crystals. They are soluble in many organic

[(PhCH2))SnhO + ArCH=CHC02H ~ [PhCH2Sn(O)(02CCH=CHAr)]6

Ar=C6H5- (1), 2-CI-C6H4- (2), 4-CI-C6H4- (3),2-02N-C6H4- (4), 3-02N-C6H4- (5),

4-02N-C6H4- (6), 4-CH)O-C6H4- (7). 2-C4H)O- (8)

Scheme I

1494 INDIAN J. CHEM. , SEC B, JULY 2004

Table I - Crystallographic data for hexameric benzyloxotin cinnamate 1.

Mol. formula C96H840lSSn6 Formular weight 459.13

Crystal system triclinic a (nm) 1.6771 (3)

b(nm) 1.8020(4) c (nm) 2.1073(4)

a(O) 108.111(3) P(O) 103 .614(3)

yeO) 104.679(3) V (nm3) 5.5033(18)

Space group p-I

Z 2

Dcal(Mg·m·3) F(OOO) 2208 1.350

J1. (mm·l) 1.396

Crystal size (mm) 0.30 X 0.25 X 0.20

Crystal colour/shape colourless/needle

Scan rangeD (0) 1.8 1-26.60

Total/unique/Rint 3 1823/2 1791/0.0836

Goodness-oF-fit 0.771

P maxi P minCe nm_3) 6.30x 102/-5.96x 102 R/wR2 0.0606/0.0698

Table II - Physical and analytical data of compounds 1-8.

Compd Yield mp Found (Calcd)% (%) "C C H N Sn

1 55 258-60(dec) 51.27 (51.53) 3.65 (3.78) 3 1.51 (31.82)

2 57 268(dec) 46.87 (47.17) 3.29 (3.22) 29.46 (29 .14)

3 60 285(dec) 47.32 (47. 17) 3. 18 (3 .22) 29.31 (29 .14)

4 63 224-25(dec) 45 .64 (45.95) 3.21 (3.13) 3.29(3 .35) 28 .68 (28.40)

5 55 234(dec) 46.14 (45.95) 3.20 (3 .13) 3. 17(3.35) 28.67 (28.40)

6 65 289(dec) 45.79 (45 .95 ) 3. 15 (3 .13) 3.40(3.35) 28.88 (28.40)

7 67 240-42(dec) 50.31 (50.66) 3.84 (4.00) 29.46 (29.45)

8 61 226(dec) 46.13 (46.33) 3.41 (3.33) 32.94 (32.70)

solvents as CCI4, CHCI3. C6H6, (CH3)2CO, but are of IR bands of these compounds have been made by insoluble in hexane, petroleum ether and water. comparison with the IR spectra related to organotin

Synthesis. Reaction of [(PhCH2h SnhO with aro- compounds, carboxylic acids and [(PhCH2h Snh O. matic substituted acrylic acids in 1:2 molar ratio gave Infrared bands corresponding to the bridging hexameric benzy loxotin aromatic substituted acry- carboxyl groups and Sn-O stretching vibration are lates. The hexameric composition apparently formed usefu l in discriminating drum structure from the as a result of slow hydrolysis of tribenzyltin aromatic other form . For compounds 1-8 , the carboxy l substituted acrylates, (PhCH2)3Sn02CCH=CHAr, the absorptions, V(eoo), appear as a symmetrical doublet major product of [(PhCH2)3Snh O and aromatic sub- centered near 1550 cm·1 ( 1587- 1530 cm· l

) which st ituted acrylic acids. indicate the presence of drum hexameric organo-

A possible mechanism is given in Scheme II. oxotin carboxylate. '2 A very strong band 598-IR spectra. The important IR spectra data of the 610 cm-I

, characteristic of the Sn-O-Sn linkage,12 is compounds are shown in Table III. The assignment assigned to VSIl -O for the drum form.

[(PhCH2)3Snh O + ArCH=CHC02H ~ (PhCH2h Sn02CCH=CHAr + H20

Scheme II

~ -2 PhCH3

PhCH2S n(OHh 02CCH=CHAr

~-H20 lPhCH2Sn(O)02CCH=CHAr]6

YIN el (II.: SYNTHESIS OF DRUM HEXAMERIC BENZYLOXOTIN AROMATIC SUBSTITUTED ACRYLATES 1495

Table 111- IH NMR and IR data of compounds 1-8

No IH NMR (ppm) rR (em- I)

v'''(C02) v'(C02) v(Sn-O-Sn) v(Sn-O)

2.95 (t, lsn_H=84_2 Hz, 12 H), 6.55 (br, 6H), 7. 15-7.40 (m, 60 H), 7.51 (br, 6 H). 1570 1531 600 545

2 2.9 1 (t, l sn_H=85.4 Hz, 12 H), 6.50 (br, 6H), 7. 18-7 .7 1 (m, 54 H), 7.94 (br, 6 H). 1578 1537 606 553

3 2.84 (t, lsn.H=82.7 Hz, 12 H), 6.75 (br, 6H,), 7.24-7.64 (m, 54 H), 7.76 (br, 6 H). 1578 1537 606 553

4 3.04 (t, l sn_H=86.5 Hz, 12 H), 6_53 (br, 6H), 7.20-7.85 (m, 60 H). 1584 1539 610 548

5 2.98 (t, l Sn_H=85.8 Hz, 12 H), 6.7 1 (br, 6H), 7.19-8 .20 (m, 60 H). 1576 1530 604 550

6 3.0 I (t, lsn.H=87.3 Hz, 12 H), 6.51 (br, 6H), 7.2 1-8. 12 (m, 60 H). 1589 154 1 602 546

7 0.90 (t, l Sn_I1=85.4 Hz, 12 H), 3.82 (5, 18 H), 7.10 (br, 6H), 7.16-7.35 (m, 60 H). 1587 1532 60 1 552

8 2.99 (t, l sn.I1=86_6 Hz, 12 H), 6.54 (br, 6H), 6.76-7.40 (m, 54 H) . 158 1 1540 598 545

IH NMR spectra. The IH NMR spectra of com­pounds 1-8 are given in Table III. The IH NMR spec­tra of compounds shown that the chemical shifts of the protons on the methylene of benzyl group of the compounds exhibit a signal about 2.84-3 .04 ppm as a triplet which is caused by the tin(11 9Sn)-hydrogen coupling, the spin-spin coupling constant } Sn-H is equal 82.7-87.3 Hz. The chemical shift of the protons of ary l group of aromatic substituted acrylate li gand exhibit signals at 6.76-8.20 ppm as mUltiplet. It is slightly larger than that corresponding free carboxylic acid. The values of the chemical shift, 7.30-7.94 for the protons of ArCH=C is greater than that of the cor­responding free carboxylic acid. In contrast, the va l­ues of the chemical shift, 6.50-7.10 for the protons of C=HCC02 is lesser than that of the corresponding free carboxylic acid. This suggests that the aromatic substituted acrylate ligand of these compounds is linked to Sn atom.

Crystal structure of hexameric benzyloxotin cin­namate 1. The unit cell contain s two independent molecules. In fact a computer fitt ing of molecules A and B shows only very marginal difference in the bond lengths and angles. One (A) of the two mole­cules is represented in Figure 1 with its numbering scheme. The molecular packing in the unit cell are shown in FigUl'e 2. Crystal data are listed in Table I. Table IV gives the selected bond lengths and angles.

In molecule A of compound 1 each of the lids of the "drum" comprises a hexagonal Sn30 3 ring of a l­ternating Sn and 0 atoms. The top lid is twisted by approximately 60° relative to the lower thereby ena­bling the formation of six Sn-O bonds which connect the lids ; the rectangular sides of the drum thus formed may be considered as Sn20 2 stannoxane group. The hexagonal lids are not planar, however, a better de­scription of thei r conformations is one based on a

somewhat fl attened chair conformation. In this com­pound, each Sn atom bonds to three framework oxy­gen atoms, where the Sn-O bonds are all of compara­ble strength and have lengths ranging from 0 .2058(8) nm to 0.2110(8) nm. The oxygen atoms of the frame­work are trivalence and have a distorted pyramidal geometry. For molecule A of compound 1, the Sn at­oms of each rectangular face are bridged by carboxy­late li gands which form two somewhat different Sn-O bonds and have lengths ranging from 0.2108(9) nm to 0.2171(10) nm. As has been observed in similar struc­tures, Sn-O bond lengths of the framework are sig­nificantly shorter than Sn-O bond lengths involving the carboxylate ligands. 12-14 The coordination geome­try about each Sn atom is completed by a C atom of the PhCH2 group which occupies a trans position to a framework 0 atom. Thus each Sn atom is coordi nated by three "framework" 0 atoms, two carboxy late 0 atoms and one C atom such that the OsC donor set defines a distorted octahedron.

Distortions from octahedron symmetry are re­flected in the interatomic angles. For instance, around the Sn(2) atom of the molecule A of compound 1, the sum of equatorial angles 0(1 )-S n(2)-0(5) 86.0(3)°, 0(8)-Sn(2)-0(5) 80.2(3)°, 0(3A)-Sn(2)-0(8) 85.4(3)°, 0(3A)-Sn(2)-0(1) 104.4(2t is equal to 356°, so the atoms 0(3A), 0(5), 0(8), 0(1) and Sn(2) are not in the same plane. The angles, 0(1)-Sn(2)-C(35) 98.0(4)°, 0(5)-Sn(2)-C(35) 94.8(3)°, 0(3A)-Sn(2)­C(35) 110.7(3)°, 0(8)-Sn(2)-C(35) 95.5(4)° are all greater than 90°. In contrast, the angles 0(2)-Sn(2)-0(1) 77.5(2)°, 0(2)-Sn(2)-0(5) 87.9(3t, 0(2)-Sn(2)-0(8) 89.5(3t, 0(3A)-Sn(2)-0(2) 77.8(2)° are less than 90°. Furthermore, the angle 0(2)-Sn(2)-C(35) being in axial place is 174.6(4)°, which deviates from linear angle 180°. These data indicate that the Sn(2) atom of the molecule A of compound 1 is in

1496 INDIAN J. CHEM., SEC S , JULY 2004

CI26l

Molec ule A Figure 1 - Molecular structu re of compound (1)

Table IV - Selected bond lengths (nm) and bond angles (0) for compound 1.

Molecu le A Molec ule n Molecule A Molecule n

Sn( I )-0(2) 0.2065(6) 0.2043(7) Sn(2)-0(8) 0.2 126(7) 0.2 132(8)

Sn( I )-O( I) 0.2073(7) 0.2079(6) Sn(2)-C(35) 0.2176(11) 0.2108(1 0)

Sn( I )-0(3) 0.2090(6) 0.2083(6) Sn(2)-0(5) 0.2 141 (7) 0.2 136(8)

Sn( I )-C(28) 0.2 126( 12) 0.2 149( II ) Sn(3)-0 (3) 0.2066(7) 0.2055(7)

Sn(I)-0(4) 0.2154(7) 0.2 124(7) Sn(3)-0( I) 0.2080(6) 0.2093(6)

Sn( I )-0(6) 0.2168(8) 0.2 148(8) Sn(3)-0(2A)" 0.2088(6) 0.2079(6)

Sn(2)-0 (3A) 0.2081 (5) 0.2074(6) Sn(3)-0 (7) 0.2141(7) 0.2 124(8)

Sn(2)-0(2) 0.2091 (7) 0.2097(2) Sn(3)-C(42) 0.2134(12) 0.2 138( I 0)

Sn(2)-0( I) 0.2107(6) 0.2106(6) Sn(3)-0(9) 0.2155(7) 0.2 180(8)

0(2)-Sn( I )-0(1) 79.0(3) 78.0(2) O( I )-Sn(2)-0 (5) 86.0(3) 85.4(3)

0 (2)-Sn( I )-0(3) 103.5(2) 104.5(2) 0(8)-Sn(2)-0(5) 80.2(3) 78.9(3)

O( 1 )-Sn( I )-0(3) 77.9(2) 77.5(3) 0(3A)-Sn(2)-C(35) 100.7(3) 100.6(4)

0(2)-Sn( I )-C(28) 101.5(4) 101.8(4) 0(2)-Sn(2)-C(3S) 174.6(4) 173.5(4)

O( I )-S n( I )-C(28) 17S.9(3) 174.3(4) O( 1 )-Sn(2)-C(35) 98.0(4) 96.2(4)

0(3)-Sn( I )-C(28) 98.0(4) 96.7(4) 0(8)-Sn(2)-C(3S) 95.5(4) 96.0(3)

0 (2)-Sn(l )-0(4) 87.0(3) 86.9(3) 0(S)-Sn(2)-C(35) 94.8(3) 96.4(4)

0(1 )-Sn(l )-0(4) 88.7(3) 88.4(3) 0(3)-Sn(3)-0( 1) 78.1 (2) 77.0(8)

0(3 )-Sn( 1 )-0(4) 160.8(3) 160.S(3) 0(3)-Sn(3)-0(2A) 78.2(2) 78.4(2)

- Collld

YIN e/ al. : SYNTHESIS OF DRUM HEXAMERIC BENZYLOXOTIN AROMATIC SUBSTITUTED ACRYLATES 1497

Table IV - Selected bond lengths (nm) and bond angles (0) for compound l-Con/d

Molecule A Molecule B Molecule A Molecule B

C(28)-Sn( I )-0 (4) 95.4(4) 96.7(4) O( I )-Sn(3)-0(2A) 104.0(2) 103.2(2)

0 (2)-Sn( I )-0 (6) 160.6(3) 159.3(3) 0(3)-Sn(3)-0(7) 90.6(3) 90.0(3)

O( I )-Sn( I )-0(6) 87.0(3) 86.4(3) 0(1 )-Sn(3)-0(7) 83.9(3) 85.9(3)

O(3)-Sn( I )-0 (6) 86.3(2) 86.4(3) 0(2A)-Sn(3)-0(7) 164.4(3) 162.0(3)

C(28)-Sn( I )-0 (6) 93.4(4) 93.7(4) 0 (3)-Sn(3)-0(9) 86.3(3) 86.4(3)

0(4)-Sn(l)-0(6) 79.3(3) 78.3(3) O( I )-Sn(3)-0(9) 155 .9(3) 160.4(3)

0(3A)-Sn(2)-0(2) 77.8(2) 77.9(2) 0(2A)-Sn(3)-0(9) 90.4(3) 87.3(3)

0 (3A)-Sn(2)-0( I) 104.4(2) 102.6(3) 0(7)-Sn(3)-0(9) 78.0(3) 80.6(3)

0(2)-Sn(2)-0( I) 77.5(2) 78.2(2) 0 (3)-S n(3)-C( 42) 171.8(4) 176.1(4)

0(3A)-Sn(2)-0(8) 85.4(3) 86.8(3) O( I )-Sn(3)-C( 42) 102. 1(4) 102.3(3)

0(2)-S n(2)-0 (8) 89.5(3) 89.8(3) 0 (2A)-Sn(3)-C(42) 93.9(4) 92.9(3)

O( I )-Sn(2)-0 (8) 161.5(3) 163.7(3) 0(7)-Sn(3 )-C( 42) 97.6(4) 99. 1 (4)

O(3A)-Sn(2)-0 (5) 159.8(3) 158.2(3) 0(9)-Sn(3 )-C( 42) 96.0(4) 93.9(4)

0(2)-Sn(2)-0 (5) 87.9(3) 89.3(3)

a Symmetry transformation used to generate equivalent atoms.

Figure 2 - Projection of the unit ce ll of compound (1)

distorted octahedron configuration. The other tin at­oms [Sn(l) and Sn(3)] of the molecule A of com­pound 1 , are similar to the Sn(2) , which are in all of distorted octahedron configuration.

The other structure may be found for monoorganotin carboxylates based on the closely related formu lation {[RSn(O)(02CR')h[RSn(02CR'h 112 15 Several crystal

structures of these have shown that the structure is based on an Sn40 4 " ladder" with bridging and chelating carboxylate ligands. Our study provides another example of the "drum" hexameric form . We note that this structural type has now been observed in some of carboxylate bound R' groups such as CH3, 12 CCh,14 and

C6H 1111 suggesting that the R' group does not play a

1498 INDIAN J. CHEM., SEC B, JULY 2004

significant role in determining the structure. This observation may be rationalized in terms of the solid state structure which shows that the R' groups are peripheral to the framework of the cluster.

Acknowledgement We acknowledge the Financial support of the Natu­

ral Science Foundation of China and the Shandong Province Science Foundation, P R China.

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