Supporting Information. for. Angew. Chem. Int. Ed. Z Wiley-VCH 2003

Transcription

1 Supporting Information for Angew. Chem. Int. Ed. Z52177 Wiley-VCH Weinheim, Germany

2 A pair of remarkably stable mononuclear chromium(iii) and chromium(iv) hydrides Alexander C. Filippou,* Sven Schneider and Gregor Schnakenburg Experimental Section 2 Preparation and characterization of 2 2 Preparation and characterization of 4 3 Details of Computational Studies 4

3 Experimental Section 2: A solution of 1 (0.770 g, 1.87 mmol) in THF (30 ml) was treated at 78 C with LisBu (1.3M solution in cyclohexane/hexane (92/8), 1.55 ml, 2.02 mmol) and then allowed to warm to ambient temperature. The colour of the solution changed gradually to olive-green. After stirring for 3 h at room temperature a 1 H NMR spectrum of an aliquote of the solution was recorded in C 6 D 6 and confirmed the complete conversion of the starting material into 2. The volatiles were removed in vacuo and the green residue extracted with pentane (50 ml). The green extract was filtered and the filtrate was concentrated in vacuo to approximately 10 ml and stored for 2 d at 35 C to complete crystallization of the product. The black microcrystals of 2 were separated from the red-brown mother liquor, washed at 60 C with pentane (2 x 10 ml) and dried for 1 h at room temperature. The product was recrystallized from pentane to afford after drying for 0.5 h under fine vacuum at room temperature 2 as black microcrystals. Yield g (72% from 1), m.p C; elemental analysis calcd (%) for C 19 H 48 CrLiN 4 OSi 3 (491.80): C 46.40, H 9.84, N 11.39; found: C 45.40, H 10.84, N (the extreme air-sensivity of 2 prevented to obtain better C,H elemental analysis values of samples, which were checked by 1 H NMR spectroscopy to be pure); IR (nujol mull/kbr): ν (cm 1 ) = 2659 (m), 1657 (s,br) (v(cr H)), 1445 (s), 1399 (w), 1347 (m), 1273 (m), 1266 (m), 1250 (s), 1237 (vs), 1214 (m), 1178 (w), 1141 (m), 1079 (m), 1055 (s), 1039 (s), 1026 (s), 951 (vs), 935 (vs,br), 888 (m), 828 (vs,br), 790 (m), 771 (s), 752 (s), 742 (s), 677 (s), 668 (s), 619 (m), 581(m), 560 (s), 535 (m), 528 (m), 463 (s), 454 (m), 426 (m); 1 H NMR (C 6 D 6, MHz, RT): δ (ppm) = 67.1 (s, v 1/2 = 5600 Hz, 1 NCH 2 ), 3.73 (s, br, 1 SiMe 3 and 2 x CH 2, THF), 2.47 (s, br, 2 SiMe 3 ), 1.86 (s, br, 2 x CH 2, THF), 16.6 (s, br, 3 NCH 2 ), 39.5 (s, v 1/2 = 4100 Hz, 1 NCH 2 ), 172 (s, v 1/2 = 8600 Hz, 1 NCH 2 ); 13 C{ 1 H} NMR (C 6 D 6, 75.5 MHz, RT): δ (ppm) = 25.8 (s, ν 1/2 = 25 Hz, 2 CH 2, THF), 35.1 (s, ν 1/2 = 2

4 140 Hz, 2 SiMe 3 ), 76.1 (s, ν 1/2 = 36 Hz, 2 CH 2, THF), 95.0 (s, ν 1/2 = 210 Hz, 1 SiMe 3 ); 13 C{ 1 H} NMR ([D 8 ]THF, 75.5 MHz, RT): δ (ppm) = 62.0 (s, ν 1/2 = 180 Hz, 2 SiMe 3 ), 97.3 (s, ν 1/2 = 210 Hz, 1 SiMe 3 ); µ eff = 3.9 µ B. 4: A solution of 3 (1.04 g, 2.33 mmol) in toluene (60 ml) was treated at 65 C with a 1M solution of Na[BEt 3 H] (2.53 ml) in toluene. The reaction mixture was slowly warmed to room temperature and stirred for 1h. During this time the colour of the solution changed from bordeaux-red to orange-red. After 6 h the solvent was removed in vacuo and the residue extracted with pentane. The extract was filtered from a greyish-white solid and the volume of the filtrate reduced in vacuo to ca. 2 ml. The solution was stored at 78 C over night to yield brick-red crystals of 4, which were collected by decantation of the mother liquor, washed with a minimum amount of pentane at 95 C and dried under fine vacuum at room temperature. Yield 0.61 g (64%), m.p C; elemental analysis calcd (%) for C 15 H 40 CrN 4 Si 3 (412.76): C 43.65, H 9.77, N 13.57; found: C 43.58, H 9.61, N 13.48; Cl < 0.22; IR (Et 2 O): ν (cm 1 ) = 1753 (m) (v(cr H)); IR (pentane): ν (cm 1 ) = 1761 (m), 1732 (sh) (v(cr H)); IR (nujol mull/nacl): ν (cm 1 ) = 2651 (vw), 1754 (sh) and 1712 (m) (v(cr H)), 1443 (m), 1398 (w), 1342 (w), 1331 (vw), 1304 (vw), 1288 (w), 1262 (m), 1241 (s), 1136 (m), 1082 (m), 1067 (m), 1055 (s), 1025 (m), 940 (vs), 921 (vs), 833 (vs,br), 800 (vs,br), 754 (s), 678 (m), 583(s); 1 H NMR (C 6 D 6, MHz, RT): δ (ppm) = 1.56 (s, v 1/2 = 170 Hz, 3 SiMe 3 ), 22.2 (s, v 1/2 = 1100 Hz, 3 CH 2 ), 203 (s, v 1/2 = 5900 Hz, 3 CH 2 ); 13 C{ 1 H} NMR (C 6 D 6, 75.5 MHz, RT): δ (ppm) = 2.6 (s, ν 1/2 = 36 Hz, 3 SiMe 3 ); µ eff = 2.9 µ B ; EI-MS (70 ev): m/z (%): 412 (37) [M] +, 411 (17) [M H] +, 311 (35) [M Me 3 SiNCH 2 ] +, 310 (10) [M H Me 3 SiNCH 2 ] +, 210 (17) [M 2 Me 3 SiNCH 2 ] +, 209 (8) [M H 2 Me 3 SiNCH 2 ] +, 196 (25) [M 2 Me 3 SiNCH 2 CH 2 ] +, 195 (15) [M H 2 Me 3 SiNCH 2 CH 2 ] +, 73 (100) [SiMe 3 ] +. 3

5 Details of Computational Studies All calculations were carried out with the program system Turbomole (V5.5) 1 and Gaussian98, Rev A SVP, DZP, TZVP and TZVPP basis sets are implemented in Turbomole, LANL2DZ (LANL2 pseudo potentials) and 6-311G(d,p) basis sets are included in Gaussian. The NBO analyses 3 and AIM analyses 4 were performed at the BP86/6-311G(d,p) optimized structures. Frequency calculations were done at the very same method/basis set combination to determine whether the optimized structures were minima on the potential energy surface. No symmetry restraints were used. 1 R. Ahlrichs, M. Bär, M. Häser, H. Horn, C. Kölmel, Chem. Phys. Lett. 1989, 162, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, V. G. Zakrzewski, J. A. Montgomery, Jr., R. E. Stratmann, J. C. Burant, S. Dapprich, J. M. Millam, A. D. Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala, Q. Cui, K. Morokuma, N. Rega, P. Salvador, J. J. Dannenberg, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. Cioslowski, J. V. Ortiz, A. G. Baboul, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, J. L. Andres, C. Gonzalez, M. Head-Gordon, E. S. Replogle, and J. A. Pople, Gaussian, Inc., Pittsburgh PA, NBO 5.0 Program. E. D. Glendening, J. K. Badenhoop, A. E. Reed, J. E. Carpenter, J. A. Bohmann, C. M. Morales, F. Weinhold, University of Wisconsin, Madison,

6 The Gibbs free Cr-H bond dissociation energies of 2 and 4 were calculated with respect to the electronic ground states of the respective fragments (doublet state for the hydrogen atom, quartet state for [CrN 3 N] and quintet state for [Li(THF)Cr(N 3 N)]) and are zeropoint energy (ZPE) corrected. Thermal corrections were carried out at standard conditions (T = K, and P = 1 atmosphere). 4 AIM2000 V1.0. F. Biegler-König, D. Bayles, J. Schönbohm, Universität Bielefeld, Deutschland,

7 obs. [Li(THF)Cr(N 3 N)H] (2) [Cr(N 3 N)H] (4) BP86/ RI- BP86/ BP86/LANL2DZ obs G(d,p) BP86/TZVP 6-311G(d,p) BP86/LANL2DZ RI- BP86/TZVP Distances [Å] Cr H 1.58(2) (3) Cr N (2) (2) Cr N (2) (2) Cr N (2) (2) Cr N (2) (2) Li N (4) Li N (4) Cr... Li 2.640(3) Li O 1.905(4) Cr (plane N1,N2,N3) Angles [ ] H Cr N (8) (9) N1 Cr N (7) (8) N2 Cr N (7) (8) N3 Cr N (6) (8) N1 Cr N (7) (8) N2 Cr N (7) (8) N1 Cr N (7) (8) Li N2 Cr 81.6(1) Li N3 Cr 80.7(1) Dihedral und torsion angles Cr N2 Li N3 19.2(2) N4-Cr-N1-Si (2) (2) N4-Cr-N2-Si (2) (2) N4-Cr-N3-Si (2) (2) (plane Cr-N2-Li)/ (plane Cr-N3-Li)

8 [Cr(N 3 N)H] [Li(THF)] + BP86/6-311G(d,p) BP86/6-311G(d,p) Distances [Å] Distances [pm] Cr H Li-O Cr N O-C α Cr N C α -C β Cr N C β C β ' Cr N Cr (plane N1,N2,N3) Angles [ ] H Cr N N1 Cr N N2 Cr N N3 Cr N N1 Cr N N2 Cr N N1 Cr N Dihedral und torsion angles Cr N2 Li N3 N4-Cr-N1-Si N4-Cr-N2-Si N4-Cr-N3-Si Natural population analysis of the separated ions [Cr(N 3 N)H] and [Li(THF)] + (optimized structures at the BP86/6-311G(d,p) level of theory) NPA charges Cr H N1 N2 N3 N4 [Cr(N 3 N)H] Natural elec. configuration (Cr) 4s d d 0.01 Li O C α C β [Li(THF)] Natural population analysis of the separated [Cr(N 3 N)H] and [Li(THF)] + ions in the frozen geometry (BP86/6-311G(d,p)) they adopt in 2. NPA charges Cr H N1 N2 N3 N4 [Cr(N 3 N)H] Natural elec. configuration (Cr) 4s d d 0.01 Li O C α C β [Li(THF)]

9 [Li(THF)Cr(N 3 N)H] (2) [BP86/6-311G(d,p)] cartesian coordinates [atom, x-, y-, z position in Å] C C N N Cr Si C C H Li N N C C C C C O Si Si C C C C C C C C C C H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H

10 [Cr(N 3 N)H] (4) [BP86/6-311G(d,p)] cartesian coordinates [atom, x-, y-, z position in Å] Cr N N N N C H H C H H C H H Si Si Si C H H C H H C H H H C H H H C H H H C H H H C H H H C H H H C H H H C H H H C H H H C H H H

11 [Cr(N 3 N)H] [BP86/6-311G(d,p)] cartesian coordinates [atom, x-, y-, z position in Å] C C N N Cr Si C C H N N C C C C C Si Si C C C C C C H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H

12 [Li(THF)] + [BP86/6-311G(d,p)] cartesian coordinates [atom, x-, y-, z position in Å] Li O C C C C H H H H H H H H