Organometallics 1995, 14, 1076-1078
1076
Synthesis and Structure of a Novel Organotin Compound, { M e 2 S n N ( C 3 N s C 1 2 ) } 3 Andrew P. Purdy* and Clifford F. George Naval Research Laboratory, Chemistry Division (Code 6120) and Laboratory for the Structure of Matter (Code 6030), Washington, D.C. 20375 Received September 19, 1994@ Summary: Cyanuric chloride reacts with tridtrimethylstanny1)amine to afford (Me3Sn)fl(Cfl&l2) (1). Prolonged heating of the reaction mixture results in the formation of the trimer {Me,&nN(Cfl3Cl2))3 (2), and the crystal structure was determined for 2*3(THF). 1 was thermally decomposed to a amorphous compound of empirical formula c6.fl6.8sn. There has been considerable recent interest in carbonic nitride (C3N4I.l Our efforts to prepare C3N4 led us to investigate the reaction between cyanuric chloride ((CNClh)and tris(trimethylstannyl)amine,2which could potentially form a C3N4 compound by elmination of 3 equiv of MesSnCl. A single cleavage product, (Me3Sn)2N(C3N&12) (11, forms fairly quickly when the reactants are heated to 80-100 “C in THF (eq 1). 1 is (CNCl),
+ (Me3Sn),N -
(Me3Sn),N(C3N3C1,)
+ Me3SnC1 (1)
1 a colorless low-melting solid t h a t sublimes a t 50 “C at lov5Torr. As expected, the volatility of 1 is about the same as the recently reported silicon analogue (Me3Si)2N(C3N3C12).3 On prolonged heating of the reaction mixture, the trimer {Me&nN(C3N3C12)}3 (2)slowly precipitates from solution. Production of 2 is accelerated by high concentrations of the reactants, which is understandable as the formation of 2 is probably due to a series of bimolecular reactions. The reaction was also performed in an NMR tube; the spectra indicate that Me4Sn is also produced at the same time as 2. The latter would suggest a process such as indicated in eq 2. Other ~ ( M ~ ~ S ~ ) Z N ( C ~ N ~ C ~{Me2SnN(C3N3CI2)h Z) + 3Me4Sn
(2)
other products
unidentified products also appear in the NMR tube reaction, presumably intermediates in the disproportionation and condensation of 1 into 2. A t a n insoluble solid is also produced upon prolonged heating in THF. To test whether 1 can be converted to carbon nitride, a sample was thermolyzed a t 350 “C in a sealed tube under N2 and then pyrolyzed under dynamic vacuum. Abstract published in Advance ACS Abstracts, January 15,1995. (1)(a) Maya, L.; Cole, D. R.; Hagaman, E. W. J . Am. Ceram. Soc. 1991,74,1686-8. (b) Sekine, T.; Kanda, H.; Bando, Y.; Yokoyama, M.;Hojou, IC J. Mater. Sci. Lett. 1990,9,1376-8.(c) Liu, A. Y.; Cohen, M. L. Phys. Rev. B 1990,41,10727-34. (d) Niu, C.; Lu, Y. Z.; Lieber, C. M. Science 1993, 261, 334-7. (e) Coad, E. C.; Apen, P. G.; Ramussen, P. G. J. Am. Chem. SOC.1994,116,391-2. (2)Lehn, W. L. J.Am. Chem. Soc. 1964,86,305. (3)Kouvetakis, J.; Bandari, A.; Todd, M.; Wilkens, B. Chem. Mater. 1994,6, 811-4. @
Figure 1. Thermal ellipsoid (20%)plot of complex 2 and three THF molecules viewed along the c axis. Only the labeled atoms are unique. The remainder of the unit cell contents is omitted for clarity. The resulting black powder has approximate composition Cs.sN6.sSnby elemental analysis and is amorphous by powder X-ray diffraction. Its infrared spectrum shows only a weak N-H stretching band, a moderately intense C=N stretch, and very strong C=N, C=C, and C-N bands. Although the silicon analogue was used in CVD experiments to make carbon nitride films,3 we did not attempt any CVD work with 1 or 2. 2 crystallized with the solvent THF in a ratio 1:3. The structure of 2*3(THF) (Figure 1) consists of a planar (Me2SnN)s ring centered on a s6 axis with three coplanar (C3N3C12) groups attached to the nitrogen atoms. The Sn-N(2) and Sn-N(6) distances of 2.746(7) and 2.807(7) A, respectively, are within the observed values for coordinate bonds between tin and neutral aromatic nitrogen ligand^.^ For example, (2,2‘azopyridine-N,N’,N”)dibr~modimethyltin~~ has Sn-N links from 2.591 to 2.904 A, and 4,4’-bipyridylbis[bromo(tri-p-tolyl)tin] has Sn-N bonds of 2.653 A.4b These weak Sn-N(2) and Sn-N(6) bonds undoubtedly contribute to the coplanarity of the (Sn-N)3 and (CNh ring systems. All but the methyl groups lie on a mirror plane. The ring atoms of THF also lie in the same mirror plane and are centered on a 63 screw axis. This forms extended planes which are separated by the (4)(a) Camalli, M.;Caruso, F.;Mattogno, G.; Rivarola, E. Znog. Chim. Acta 1990,170,225.(b)Bajue, S. A.; Bramwell, F. B.; Charles, M.; Carvantes-Lee, F.;Pannell, K. Inorg. Chim.Acta 1992,197, 83.
This article not subject to U.S. Copyright. Published 1995 by the American Chemical Society
Notes
Organometallics, Vol. 14, No. 2, 1995 1077 Table 3. Selected Bond Lengths (A) and Angles (deg) for 2.3 (THFP
Table 1. Experimental Data for X-ray Diffraction of 2*3(THF) formula
[C1d%&zCkSn31.3 tC4HsOI 1151.5 hexagonal P63/m 18.581(8) 7.589(6) 90 120 2269(2) 2 1.685 1128 0.71073 2.03 295 0.22 x 0.40 x 0.60 8-28 55 3921 1901 1623 101 full-matrix least squares on Fz 0.053, 0.127
fw cryst syst space group a, b (A) c
(A)
a,B ( k ) Y (deg)
cell vol (A3) Z density (p/cm3) F(o00) 2 (Mo Ka) (A) P ("-9 temp (K) cryst size (mm) scan mode 28,, (de& no. of reflnslmeasd no. of unique reflns no. of reflns ( I > 2u(I)) no. of variables refinement R, wR2 a a
R = CIFo - Fcl/C(Fo);wR2 = {C[w(Fo2- F ~ ) 2 1 / ~ [ w ( F o 2 ) z ] } " 2 .
Table 2. Atomic Coordinates ( x 104) and Equivalent Isotropic Displacement Parameters (Azx 103) for 2*3(THF) Sn(1) Cl(1) Cl(2) N(1) C(1) N(2) C(3) N(4) (35) N(6) (37) O(2S) C(W C(3S) C(4S) (35s) a
X
Y
Z
5258(1) 5395(2) 3009(2) 5926(4) 5386(4) 5667(4) 5065(6) 4255(5) 4057(5) 4559(4) 4708(5) 190(26) 825(19) -531(19) -206(27) 667(26)
2399(1) 6050(2) 3007(2) 3718(4) 3971(5) 4812(4) 4997(5) 4499(5) 3706(5) 3398(4) 2041(4) 1305(23) 1968(20) 1356(26) 2226(29) 2608(20)
2500 2500 2500 2500 2500 2500 2500 2500 2500 2500 5010( 10) 2500 2500 2500 2500 2500
&aa
42( 1) 94(1) W1) 48( 1) 45(2) 53m 56(2) 65(2) 54(2) 4%1) 7W) 351(20) 206(12) 287(22) 227(14) 233( 14)
Ues is defined as one-third of the trace of the orthogonalized Uij tensor.
methyl groups and THF hydrogens forming sandwiched planes spaced l/zc along the c axis. The crystal data and atomic coordinates are listed in Tables 1 and 2, respectively, and a list of selected bond lengths and angles is presented in Table 3. Structures of six-membered Sn-N ring compounds are relatively rare in the literature, the only other example being ( ( M ~ ~ C ) ~ S ~ NThe H ) SSn-N . ~ ring in the latter is also planar with N-Sn-N and Sn-N-Sn angles of 107.8(2) and 132.2(3)', respectively. Comparable angles in 2 are 98.0(3) and 142.0(3)'; the large (9.8') difference in internal angles is probably due to Sn-N coordination as well as steric effects from the dimethyl and bulky (C3N3C12) substituents on adjacent atoms. In contrast, the Si3N3 ring in (Me2SiNPh)a is substantially nonplanar.6 Coordination between Sn and ring nitrogens is probably also responsible for a C-Sn-C angle of 129.5(5)", which is wider than the C-Sn-C angle in ((Me3C)2SnNH)3(115.7(3)"),despite the bulky (5) Puff,H.; Hanssgen, D.; Beckermann, N.; Roloff, A.; Schuh, W. J . Organomet. Chem. 1989,373,37-47. ( 6 )Blake, A. J.; Ebsworth, E. A. V.; Kulpinski, J.; Lasocki, Z. Acta Crystallogr. 1991, C47, 1440-2.
Sn(l)-N(l)I Sn( 1)-C(7) C1( 1)-C(3) N(l)-W) C(l)-N(6) ~(2)-~(3) N(4)-C(5) SII(~)~-N(~)
2.104(7) 2.107(7) 1.733(8) 1.303(10) 1.362(9) 1.324(10) 1.328(11) 2.746(7)
N(1)1-Sn(l)-C(7)2 C(7)2-Sn(l)-C(7) C(7)2-Sn(l)-N(1) c(l)-N(l)-S~~(l)~ S~~(l)~-N(l)-sn(l) N(l)-C(l)-N(2) C(3)-N(2)-C( 1) N(4)-C(3)-Cl(l) C(3)-N(4)-C(5) N(6)-C(5)-C1(2) C(5)-N(6)-C(1) n
106.5(2) 129.5(5) 106.0(2) 110.2(5) 142.0(3) 119.0(6) 113.8(6) 115.5(6) 111.5(6) 116.9(6) 115.3(6)
SII(~)-C(~)~ Sn(1)-N( 1) C1(2)-C(5) N(l)-Sx~(l)~ C(l)-N(2) C(3)-N(4) C(5)-N(6) Sn( 1)-N(6) N(l)I-Sn(l)-C(7) N(l)I-Sn(l)-N(l) C(7)-Sn(l)-N(l) C(1)-N(1)-Sn(1) N(1)-C(1)-N(6) N(6)-C(l)-N(2) N(4)-C(3)-N(2) N(2)-C(3)-Cl(l) N(6)-C(5)-N(4) N(4)-C(5)-C1(2)
2.107(7) 2.122(6) 1.717(8) 2.104(6) 1.379(9) 1.313(12) 1.317(10) 2.807(7) 106.5(2) 98.0(3) 106.0(2) 107.8(5) 119.3(6) 121.7(6) 129.4(7) 115.1(7) 128.2(7) 114.8(6)
Symmetry transformationsused to generate equivalent atoms: Iy 112; 3-x y 1, -x 1, z.
- y, z; zx, y. -z
+
+ +
+
+ 1,
CMe3 groups in the latter. The Sn-N(l) distances of 2.014(7) and 2.122(6) A are longer than those observed in ((Me3C)2SnNH)3but shorter than the Sn-N distances in a series of Sm(NR)30 and Sm(NR)4 cage compounds (2.17-2.29 A).'
Experimental Section All manipulations of air-sensitive compounds were performed in a Vacuum Atmospheres Drilab or on a vacuum line. Solvents were distilled from sodium-benzophenone ketyl and deuterated NMR solvents were distilled from Na/K on the vacuum line. Tris(trimethylstanny1)amine was prepared by literature methods;2 all other chemicals were obtained from Aldrich Chemical Co. Cyanuric chloride was recrystallized from CC14 and sublimed before use. All NMR spectra were recorded on either a Bruker MSL-300 or an AC-300 spectrometer. Infrared spectra were obtained on either a Nicolet Magna-IR 750 FTIR or a Perkin Elmer 1430 ratio recording infrared spectrometer. Mass spectra were obtained on a Finnigan-MAT TSQ-70 instrument using electron ionization at 70 eV. Elemental analyses were performed by E+R Microanalytical Laboratories Inc., Corona, NY. Reaction of (CNC1)s with (Me3Sn)sN. (a) Cyanuric chloride (0.207 g, 1.12 mmol) and tris(trimethylstanny1)amine (0.567 g, 1.12 mmol) were combined in 10 mL of THF in a tube equipped with a stir bar and Kontes valve and stirred for 4 days at 85 "C. The mixture was then fractionated on the vacuum line between a -45 "C trap and a -196 "C trap, with the reaction bulb at room temperature. The volatile solid condensed in the -45 "C trap was identified as MesSnCl from its mass spectrum, and the liquid residue in the reaction bulb showed two components in its NMR spectrum. Vacuum distillation of the residue with a short-path apparatus, using a heat gun as the heat source, afforded 0.335 g of 1 (61%). (b) Cyanuric chloride (0.196 g, 1.06 mmol) and (Me8Sn)sN (0.539 g, 1.07 mmol) were mixed with 2 mL of THF and heated at 90 "C for 11 days. The mixture was recrystallized from a hot CsH$THF mixture, and the resulting solid was recrystallized again from THF and dried under vacuum at 100 "C, affording 66.6 mg (20%)of 2. A reaction of the same quantities of reactants in 15 mL of THF at 90-100 "C for 70 days produced 2 and a tan solid of the following elemental composition: C, 32.34; H, 2.37; N, 28.96; Sn, 8.29. (7) (a)Veith, M.; Recktenwald, 0.2.Naturforsch. 1981,36B, 1449. (b) Veith, M. 2. Naturforsch. 1980, 35B, 20-4. (c) Veith, M.; Recktenwald, 0.2.Naturforsch. 1983,38B, 1054-61.
1078 Organometallics, Vol. 14,No.2, 1995 Data for 1: NMR (CeD6) 'H 6 0.238; I3C 6 -3.09 (SnMed, 169.2 (2C), 171.7 (10. Anal. Found (Calcd) for CgHleN4Cl~Snz: C, 21.92 (22.04);H, 3.85 (3.70); N, 11.51 (11.42); C1,14.69 (14.45). Data for 2: NMR (C4D80) 'H 6 0.85; 13C 6 1.80 (SnMez), 169.1(2C), 171.5 (1C). Anal. Found (Calcd) for C&1a&16Sn3: C, 19.30 (19.27); H, 1.71 (1.94);N, 17.90 (17.97); C1,22.79 (22.75). Thermolysis of 1. 1 (152 mg) was sealed in a Pyrex tube under 1 atm of Nz. The tube was heated in a furnace from 300 to 350 "C for 1 h and then opened in the drybox after cooling. The brown solids were scraped into a quartz tube and heated under vacuum to 200 "C, during which the volatile materials were collected in a vacuum trap held at -196 "C and identified as primarily MejSnCl. The temperature was raised to 475 "C, and the volatiles evolved over the next 2 h were collected in a separate trap held at -196 "C. Final temperature is 520 "C. An insoluble, unidentified white solid also sublimed during the final pyrolysis, and a ring of a tiny amount of black sublimate was also present. The material in the latter vacuum trap was identified as mostly HCN by IR. The black solid product (34.0 mg) had an elemental analysis as follows: C, 27.71; H, 0.1; N, 32.02; Sn, 39.73. IR (KBr pellet) 3450 (br, w, NH),2137 (m, CEN), 1637 (8,C=C), 1407 (br, vs), 1315 (br, vs), 1163 (br, s), 990 (br, m), 801 (m), 525 (br, w) (1407-990 peaks are bumps on a single broad hump, probably C=N, C-N, and C-C). Structure Determination of 2*3(THF). Crystals of 2.3(THF) were mounted in thin-walled capillaries containing a
Notes small amount of THF under helium atmosphere. The data were collected on a Siemens P3N diffractometer equipped with an incident beam graphite monochromator. The data were corrected for Lorentz and polarization effects and semiempirical absorption corrections were applied. Maximum and minimum transmissions were 0.67 and 0.30. Direct methods were used to determine the structure, which was refined using the program SHELXTL93.8 The parameters refined include the coordinates and anisotropic thermal parameters for all but the hydrogen atoms. Hydrogen atoms were placed in idealized positions, and the coordinate shifts for carbon were applied to the bonded hydrogens. Hydrogen isotropic thermal parameters were set at 1.2 times the Ues of bonded carbons. Additional data collection and refinement parameters are given in Table 1.
Acknowledgment. We thank the ONR for financial support, and John Callahan (NRL) for obtaining the mass spectra. Supplementary Material Available: A list of anisotropic displacement parameters and hydrogen atom coordinates for 2 (1 page). Ordering information is given on any current masthead page.
OM940727U (8)Sheldrick, G. M. SHELXQ3,program for refinement of crystal structures, Beta test version, University of Gijttingen, Germany, 1993.
