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1 Supporting Information Wiley-VCH Weinheim, Germany

2 From the alkyllithium aggregate [(nbuli) 2 PMDTA] 2 to lithiated PMDTA Carsten Strohmann*, Viktoria H. Gessner Institut für Anorganische Chemie, Universität Würzburg, Am Hubland, Würzburg, Germany mail@carsten-strohmann.de Experimental Details All experiments were carried out under a dry, oxygen-free argon atmosphere using standard Schlenk techniques. Involved solvents were dried over sodium and distilled prior to use. Synthesis of [(nbuli) 2 PMDTA] 2 (4 2 ) 170 mg (0.98 mmol) N,N,N,N,N -Pentamethyldiethylentriamin (PMDTA) were dissolved in 5 ml n-pentane and cooled to 78 C. At this temperature 1.3 ml (2.56 mmol) nbuli (1.6 M in hexane) were carefully added to give two phases. Warming up to 45 C gave [(nbuli) 2 PMDTA] 2 as colorless needles. NMR Analyses The crystals of [(nbuli) 2 PMDTA] 2 were dissolved in toluene-d 8 at 223 K. NMR analyses were accomplished at same temperature. At this temperature the signals are broadened. Analysis at lower temperatures is not possible because of the low solubility in toluene. Above 253 K deprotonation of PMDTA starts. 1 H-NMR (500.1 MHz, Tol-d 8 ): d = 0.58 (br, 4H; CH 2 Li), 1.30 [br, 6H; CH 3 (CH 2 ) 3 Li], 1.77 (br, 12H; CH 2 + NCH 2 ), 1,94 (br, 4H; NCH 2 ), 2.14 (br, 15H; NCH 3 ). { 1 H} 13 C-NMR (125.8 MHz, Tol-d 8 ): d = (br) (CH 2 Li), 14.9 [CH 3 (CH 2 ) 3 Li], (2C, br) [CH 3 (CH 2 ) 2 CH 2 Li], 44.0 (NCH 3 ), 45.6 (4C) (NCH 3 ), 53.0 (2C, br), 56.8 (2C, br) (NCH 2 C). 7 Li-NMR (59.6 MHz, Tol-d 8 ):?d = 2.4 (br). Synthesis of N-Lithiomethyl-N,N,N,N -tetramethyldiethylen-triamin (3) 1) 180 mg (1.04 mmol) N,N,N,N,N -Pentamethyldiethylentriamin (PMDTA) were dissolved in 3 ml n-pentane and cooled to 78 C. At this temperature 0.65 (1.04 mmol) nbuli (1.6 M in hexane) were carefully added and the solution was warmed up to room temperature. After stirring at room temperature for 1 hour the solution was again cooled down to 78 C to give the crystalline product as small colorless rhombi. 2) Crystalls of better quality were obtained via: 170 mg (0.98 mmol) N,N,N,N,N -Pentamethyldiethylentriamin (PMDTA) were dissolved in 4 ml n-pentane and cooled to 78 C. At this temperature 1.5 ml (1.05 mmol) iprli (0.7 M in n-pentane) were carefully added and the solution was warmed up to 0 C. After stirring at 0 C for 45 min the solution was again cooled down to 78 C to give the crystalline product as colorless rhombi. 1

3 Computational Studies Starting coordinates for the monomeric structures were obtained with Chem3DUltra 6.0 and preoptimized with PM3. For 2 2 -C i, [(nbuli) 2 PMDTA] 2 and [nbuli] 6 starting coordinates were taken from the crystal structures. The coordinates for TS-3, TS-4 and 2 2 -C 2 are based on the corresponding dimer in the crystal. All monomeric structures were calculated without symmetry restriction, whereas 2 2 -C 2 is C 2 -symmetric and [(nbuli) 2 PMDTA] 2, TS-3, TS-4, [nbuli] 6 as well as 2 2 -C i are C i -symmetric. As coordinated PMDTA has no symmetry the outer methyl groups of PMDTA differ from each other. Because of that the transition states of the deprotonation of both sides of PMDTA and of the inner methyl group were localized, as well as transition states, which differ in the conformation of n- butyllithium. Table 1 shows the transition states with the lowest energies. For all compounds the global minima and vibrational frequency analyses were subsequently energy-optimized at B3LYP/6-31+G(d) or B3LYP/6-31+G level. For the educt no negative vibrations were obtained whereas Pro-1 showed one small imaginary vibration due to the relative motion of free n-butane molecule to the lithiated PMDTA. The transition states exhibit exactly one imaginary frequency in the direction of the expected reaction coordinate. In the case of TS-3 and TS-4 two imaginary frequencies were obtained, one for the symmetric and one for the asymmetric motion of the two proton transfers. Because of the high flexibility of the central n-butane molecule an additional small imaginary frequency is observed. Calculations without symmetry restriction, which are limited by the size of TS-3 and TS-4, should lead to only one imaginary frequency. Nevertheless, the calculated deprotonation processes and the energies should correspond to these transition states. Due to the two simultaneous deprotonation processes the obtained energies of TS-3 and TS-4 have to be halved for comparison with the monomeric transition states. Table 1 lists all total (SCF) and zero-point energies (ZPE) of the educts, products and transition states of the lithiation of PMDTA at the outer and inner methyl group. All energies mentioned in the publication are zero-point energies (ZPE). In addition to the C i -symmetric, dimeric transition states, TS-3 and TS-4, the unsymmetrical transition states TS-3-C 1 and TS-4-C 1 were calculated. The energy optimisation yielded the values shown in table 1. TS-3-C 1 shows a barrier of kj mol -1 (SCF), TS-3-C 1 a barrier of kj mol -1 (SCF). Due to these results the barriers of the deprotonation of the outer and inner methyl groups differ only marginally from the symmetric transition states. These small differences affirm that the consideration of the symmetric transition states is adequate for the deprotonation process. Table 1 Results from Quantum Chemical Studies on the lithiation of PMDTA. Compound method/basis Min./TS SCF (Hartree) ZPE (Hartree) Min-1 B3LYP/6-31+G(d) Global Min Pro-1 B3LYP/6-31+G(d) Global Min Pro-2 B3LYP/6-31+G(d) Global Min TS-1 B3LYP/6-31+G(d) TS TS-2 B3LYP/6-31+G(d) TS C 2 B3LYP/6-31+G(d) Global Min C i B3LYP/6-31+G(d) Global Min B3LYP/6-31+G(d) Global Min [(nbuli) 2 PMDTA] 2 B3LYP/6-31+G Global Min TS-3 B3LYP/6-31+G TS TS-4 B3LYP/6-31+G TS TS-3-C 1 B3LYP/6-31+G TS TS-4-C 1 B3LYP/6-31+G TS PMDTA-Li B3LYP/6-31+G Global Min. 686, , [nbuli] 6 B3LYP/6-31+G Global Min

4 Table 2 Standard orientation and MOLEKEL plot of Min-1 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol X Y Z C C N C C C N C N 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 C Li C C C H H H H H H H H H

Table 3 Standard orientation and MOLEKEL plot of the product of the lithiation of the outer methyl group of PMDTA, Pro-1 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C -4.599739-0.582382 0.

5 Table 3 Standard orientation and MOLEKEL plot of the product of the lithiation of the outer methyl group of PMDTA, Pro-1 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C C C C N C C C Li N C N 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

6 Table 4 Standard orientation and MOLEKEL plot of the product of the lithiation of the inner methyl group of PMDTA, Pro-2 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C C N C C C Li N C N 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 C C C C H H H H H H H H H H C H N Li N N Pro-2 5

Table 5 Standard orientation and MOLEKEL plot of the deprotonation of the outer methyl group of the monomer, TS-1 [transition state, B3LYP/6-31+G(d)]. Atomic Symbol x y z C -3.170422-0.126456-1.

7 Table 5 Standard orientation and MOLEKEL plot of the deprotonation of the outer methyl group of the monomer, TS-1 [transition state, B3LYP/6-31+G(d)]. Atomic Symbol x y z C C C C N C C C Li N C N 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

8 Table 6 Standard orientation and MOLEKEL plot of the deprotonation of the inner methyl group of the monomer, TS-2 [transition state, B3LYP/6-31+G(d)]. Atomic Symbol x y z C C C N C C C Li N C C C C N 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

Table 7 Standard orientation and MOLEKEL plot of the C 2 symmetric dimeric lithiated PMDTA 2-C 2 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C 3.024714 0.222409 2.716586 N 3.070253-0.

9 Table 7 Standard orientation and MOLEKEL plot of the C 2 symmetric dimeric lithiated PMDTA 2-C 2 [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C N C C C C Li N C C N C C C N C C C C Li N C C N 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 -5.485649-1.092334-0.409695 H -5.198431 0.340983 1.522662 H -4.548499 1.201085 0.132314 H -1.880128 1.948946 2.353144 H -3.521156 2.515991 2.017685 H -2.825406-2.934262-0.805274 H -4.180264-2.

10 H H H H H H H H H H H H H H H H H H Table 8 Standard orientation and MOLEKEL plot of the C i symmetric dimeric lithiated PMDTA, 2-C i [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z H H H H H C H H C H H C H H H H H C N H N H C H C H C H N H H C

11 C H C H H Li C H H Li H N C C H H H H N C C H N H C H H H H H C H H H C H H H

Table 9 Standard orientation and MOLEKEL plot of the inner lithiated monomeric PMDTA [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C -2.898616 1.318635 1.095220 C -2.366025-0.711746-0.

12 Table 9 Standard orientation and MOLEKEL plot of the inner lithiated monomeric PMDTA [global minimum, B3LYP/6-31+G(d)]. Atomic Symbol x y z C C N C C C Li N C N 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

Table 10 Standard orientation and MOLEKEL plot of [(nbuli) 2 PMDTA] 2 [global minimum, B3LYP/6-31+G]. Atomic Symbol x y z C -2.671971 3.614704-3.334209 C -2.716955 3.616942-1.794755 C -1.472338 2.

13 Table 10 Standard orientation and MOLEKEL plot of [(nbuli) 2 PMDTA] 2 [global minimum, B3LYP/6-31+G]. Atomic Symbol x y z C C C C Li Li Li Li C C C C H H H H H H H H H H H H H H H H H H C C C N C N C C C N C C H H H H H H H H H H H

14 H H H H H H H H H H H H C C N C C C N C N 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 C C C C H H H H H

15 H H H H C C C C H H H H H H H H H

16 Table 11 Standard orientation and MOLEKEL plot of the deprotonation of the outer methyl groups of the dimer TS- 3 [transition state, B3LYP/6-31+G]. Atomic Symbol x y z C C C C Li Li Li Li C C C C H H H H H H H H H H H H H H H H H H C C C N C N C C C N C C H H H H H H H H H

17 H H H H H H H H H H H H H H C C N C C C N C N 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 C C C C H H H

18 H H H H H H C C C C H H H H H H H H H Table 12 Standard orientation and MOLEKEL plot of the deprotonation of the inner methyl groups of the dimer, TS- 4 [transition state, B3LYP/6-31+G]. Atomic Symbol x y z C C C C Li Li Li Li C C C C H H H H H H H H H H H H H H H H H H

19 C C C N C N C C C N C C H H H H H H H H H H H H H H H H H H H H H C C N C C C N C N C C C H H H H H H H H H H H

20 H H H H H H H H H H C C C C H H H H H H H H H C C C C H H H H H H H H H H H H H

Table 13 Standard orientation and MOLEKEL plot of the unsymmetrical transition state TS-3-C 1 of the deprotonation of one outer methyl group of the dimer; [transition state, B3LYP/6-31+G].

21 Table 13 Standard orientation and MOLEKEL plot of the unsymmetrical transition state TS-3-C 1 of the deprotonation of one outer methyl group of the dimer; [transition state, B3LYP/6-31+G]. Atomsymbol x y z Li C C C C H H H H H H H H H Li Li 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 Li C C C C C C C N C

22 N C C C N 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 C C C N C N C C C N C C H H H H H

23 H H H H H H H H H H H H H H H H H H Table 14 Standard orientation and MOLEKEL plot of the unsymmetrical transition state TS-4-C 1 of the deprotonation of one outer methyl group of the dimer; [transition state, B3LYP/6-31+G]. atomic symbol x x z C C C C H H H H H H H H H C C C C Li Li Li C C C C H H H H H H H TS-4-C 1 22

24 H H H H H H H H H H H C C C C H H H H H H H H H Li C C N C C C N C N C C C H H H H H H H H H H H H H H H H H H H

25 H H H H C C C N C N C C C N 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

26 Table 15 Standard orientation and MOLEKEL plot of [nbuli PMDTA] [global minimum, B3LYP/6-31+G]. Atomic Symbol x y z C C N C C C N C N 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 C Li C C C H H H H H H H H H

27 Table 16 Standard orientation an MOLEKEL plot of n-butyllithium hexamere [global minimum, B3LYP/6-31+G]. Atomic Symbol x y z H H H H C H H C H H C C H H C H H H H C C H Li H C H H H H H H H H H H C C C C Li H C H C Li Li H C Li H H H C H

28 H H H H H H C Li H C C H H H H H C C H C H H C H H H H C H H Complete ref. 16: Gaussian 03 (Revision B.04), M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, 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, C. Gonzalez, and J. A. Pople, Gaussian, Inc., Pittsburgh, PA,

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