The Reaction of Cp(Cl)M(Diene) (M = Ti, Hf) with Isonitriles

  Supporting Information The Reaction of Cp*(Cl)M(Diene) (M = Ti, Hf) with Isonitriles

  Travis N. Valadez, Jack R. Norton,* and Michelle C. Neary

  Department of Chemistry, Columbia University, New York, New York 10027, United States

  Table of Contents: General Methods

  S2 Materials

  S3 Synthetic Procedures

  S3 Figure S1. ORTEP view of other enantiomer of the titanaaziridine 3 S7 References

  S8 Spectra

  S9

  

General Methods. Unless otherwise noted, all manipulations were carried out in an

  inert atmosphere box (O 2 < 1 ppm) or under Ar by standard Schlenk techniques. Glassware was flame or oven-dried immediately prior to use. NMR spectra were recorded on a Bruker 300 MHz, 400 MHz, or 500 MHz instrument. High resolution mass spectra were acquired on a Agilent 6220 Acccurate-Mass Time-of-Flight LC/MS. X-ray diffraction data were collected on a Bruker Apex II diffractometer. Crystal data, data collection and refinement parameters are summarized in Table 1. The structure was solved using direct methods and standard difference map techniques, and was

  2

  refined by full-matrix least-squares procedures on F with SHELXTL (Version

  1 2013/4).

  Table 1. Crystal, intensity, collection, and refinement data.

  Cp*TiCl(N

^{2 C}

^{28 H 40 ) (3) Cp*HfCl(N 2 C 24 H 28 ) (16)}

  lattice Monoclinic Monoclinic formula C H ClN Ti C H ClHfN

  38

  

55

  2

  34

  43

  2

  formula weight 623.19 693.64 space group ^{1 1} P2 /n P2 /c 22.398(10) 20.797(18)

  a/Å b/Å 14.930(6) 8.479(7) c/Å 22.677(10) 18.876(16)

  90

  90 /˚

  117.472(6) 114.132(15) /˚

  90

  90 /˚

3 V/Å 6728(5) 3038(5)

  Z

  8

  4 temperature (K) 130(2) 180(2) 0.71073 0.71073 radiation ( , Å)

• 3

  1.230 1.517 ρ (calcd.) g cm

• 1

  0.362 3.547  (Mo K), mm

  24.712 31.076  max, deg. no. of data collected 71608 24093 no. of data 11470 9599 no. of parameters 772 542 _{1 0.0965 0.0666}

  R [ I > 2σ(I)] _{2 0.2524 0.1245} wR [ I > 2σ(I)] _{1 0.1883 0.1275} R [all data] _{2 0.3226 0.1428} wR [all data]

  GOF 1.030 1.003

  R int 0.2420 0.0861 Materials. Tetrahydrofuran and benzene were distilled from

  sodium/benzophenone ketyl under N

  2 . Pentane was stirred over sulfuric acid for several days to remove any olefins, and then was distilled from sodium under Ar.

  Deuterated solvents (Cambridge Isotopes) were purified by vacuum transfer from the appropriate drying agent (Na/Ph CO for C D and THF-d , CaH for Tol-d ).

  2

  

6

  6

  8

  2

  8 Synthetic Procedures. Cp*TiCl 3 was generously donated by Boulder

  Scientific. Cp*HfCl

  3 was purchased from Strem Chemicals and used as received. 2,3-

  Dimethylbutadiene was purchased from Acros and vacuum transferred from BHT immediately prior to use. Cp*(Cl)Ti(2,3-dimethylbutadiene) (1) and Cp*(Cl)Hf(2,3- dimethylbutadiene)(THF) (14-THF) were prepared by modification of the literature

  2

  procedures. 14-THF was prepared according to the literature method and purified

  13

  by recrystallization from pentane. 2,6-(CH ) C H N C was prepared according to the

  

3

  2

  6

  3

  13

  3 literature procedure using C labeled formic acid. _2b (C ^{5 (CH 3 ) 5 )(Cl)Ti(2,3-dimethylbutadiene) (1). To a red solution of}

  Cp*TiCl

  3 (2.80 g, 9.67 mmol) and 2,3-dimethylbutadiene (1.7 mL, 12.0 mmol) in THF

  (150 mL) was added iso-butylmagnesium chloride (2.0 M, 10.0 mL, 20.0 mmol) dropwise at

• –78°C. After stirring for 1h at –78°C the yellow mixture was warmed to 0°C and slowly became green. After 2h at 0°C the mixture was concentrated and the resulting solid was extracted with pentane (90 mL). The deep green solution was concentrated to ~40 mL and cooled to
• –78°C for 4h, giving dark blue crystals of 1

  1

  (1.40 g, 48% yield). H NMR (500 MHz, C

6 D

  

6

  ) δ 2.72 (d, J = 8.2 Hz, 2H), 1.89 (s, 6H), 1.87 (s, 15H), 1.38 (d, J = 8.2 Hz, 2H).

  (C ^{5 (CH 3 ) 5 )(Cl)Ti(N-(tert-butyl)-2-((tert-butylimino)methyl)-3,4-dimethyl}

cylopent-3-en-1-imine) (2). To a solution of Cp*(Cl)Ti(2,3-dimethylbutadiene) (1)

  (1.20 g, 4.0 mmol) in C H (40 mL) was added tert-butyl isonitrile (905 µL, 8 mmol).

  6

6 The solution color immediately changed from deep blue to dark green-brown. After 10 min at RT, the solution was concentrated in vacuo to give a dark green powder.

  The green solid was dissolved in pentane (50 mL) and the resulting solution was cooled to

• –78 °C for 5h. The resulting olive green powder was isolated via cannula

  1

  filtration and rinsed with cold pentane (1.22 g, 2.64 mmol, 66% yield). H NMR (400 MHz, C D , 298 K)

  6

  6

  δ 2.97 (bs, 1H), 2.75 (d, J = 21.8 Hz, 1H), 2.50 (d, J = 4.2 Hz, 1H), 2.36 (d, J = 21.8 Hz, 1H), 2.00 (s, 15H), 1.60 (s, 3H), 1.36 (s, 3H), 1.34 (s, 9H), 1.27 (s,

  13

  9H). C NMR (126 MHz, C D 298 K

  6 6,

  ) δ 192.62, 134.67, 127.62, 122.43, 76.22, 73.05,

• 1

  61.79, 59.92, 41.56, 31.87, 29.93, 14.20, 12.83, 12.50. IR (NaCl) 1718 cm (C=N stretch).

  (C ^{5 (CH 3 ) 5 )(Cl)Ti(N-(adamant-1-yl)-2-((adamant-1-ylimino)methyl)-3,4-} dimethylcylopent-3-enimine) (3). To a solution of Cp*(Cl)Ti(2,3-

  dimethylbutadiene) (1) (200 mg, 0.668 mmol) in C H (15 mL) was added 1-

  6

  6

  adamantyl isonitrile (216 mg, 1.34 mmol) in C H (15 mL). After 10 min, removal of

  6

  6

  solvent in vacuo gave a dark residue. Washing the residue with pentane (25 mL)

  1

  afforded 3 as a green powder (291 mg, 70% yield). H NMR (500 MHz, C D )

  6

  6

  δ 3.07 (s, 1H), 2.90 (d, J = 21.6 Hz, 1H), 2.52 (m, 2H), 2.19 (d, J = 10.9 Hz, 3H), 2.11 (d, J = 8.7 Hz, 6H), 2.04 (s, 15H), 2.00

• –1.89 (m, 12H), 1.74 (d, J = 11.7 Hz, 3H), 1.67 (m, 9H), 1.52

  13

  (d, J = 12.2 Hz, 3H), 1.41 (s, 3H). C NMR (126 MHz, C

  6 D

  6

  ) δ 191.08, 134.67, 127.79, 122.53, 74.95, 73.37, 63.00, 61.51, 45.13, 42.02, 40.02, 37.69, 36.78, 31.22, 30.75, 14.29, 13.04, 12.74. Single crystals suitable for X-ray diffraction were grown from a concentrated pentane solution at _t –35 °C over 6h.

  (C ^{5 Me 5 )(Cl)Ti(N Bu)(NC 5 H 5 ) (10) + 3,4-dimethyl-}

  -methylene

  cyclopentenimine (11). Pyridine (0.0275 mmol, 27.5 µL of 1M solution in C

  6 D 6 ) was

  added to solution of 2 in C

  6 D 6 (600 µL). The resulting dark green solution was heated

  at 55°C for 2h to give a red solution of 10 and 11 (yield of both 10 and 11 >90% from

  4

  1 2 relative to internal standard). 10 is a known compound. H NMR (500 MHz, C D

  6

  6

  ) δ (10) 8.47 (bs, 2H), 6.69 (br, 1H), 6.38 (br, 2H), 2.03 (br, 15H), 1.24 (s, 9H); (11) 6.03 (bs, J=1.2 Hz 1H), 4.82 (bs, J=1.2 Hz, 1H), 2.68 (s, 2H), 1.63 (s, 3H), 1.50 (s, 3H), 1.30

  13

  (s, 9H). C NMR (126 MHz, C

6 D

  6

  ) δ (10) 151.34 (o-C), 138.42 (p-C), 124.36 (m-C), _t 120.27 (C

  5 Me 5 ), 68.92 (NCMe 3 ), 32.74 (NCMe 3 ), 12.54 (C

  5 Me 5 ); (11) 163.25 (C=N Bu),

  153.20 (C=CH

  2 ), 137.13 (C(Me)C(Me)), 134.41 (C(Me)C(Me)), 102.38 (C=CH 2 ), 56.36

  (NCMe

  3 ), 41.18 (CH 2 ), 30.68 (NCMe 3 ), 14.58 (CH 3 ) 10.44 (CH 3 ). 11 can be separated t

  from (C Me )(Cl)Ti(N Bu)(NC H ) (10) via vacuum transfer. However, material

  5

  5

  5

  5

  obtained in this way is not analytically pure and cannot be purified by

  chromatography. HRMS (11) m/z calculated for C H N (M+H) 178.15903, found

  12

  20

• 1 178.15917. IR (NaCl) (11) 1618 cm (C=N stretch).

  Cp*HfCl(N ^{2 C 24 H 28 ) (16). The diazahafnacyclopentane 16 was prepared}

  5

  according to the procedure of Teuben. A solution of 2,6-dimethylphenyl isonitrile (10.5 mg, 0.08 mmol) in C

  6 D 6 (200 µL) was added dropwise to a solution of

  Cp*(Cl)Hf(2,3-dimethylbutadiene)(THF) (14-THF) (21 mg, 0.04 mmol) in C D (600

  6

  6

  1

  µL). The resulting red solution was left overnight. The H NMR spectrum of the

  5

  1

  product was identical to that of compound 15 reported by Teuben. H NMR (500 MHz, C

  6 D 6 )

  δ 7.17-6.84 (m, 6H), 3.03 (d, 17.0 Hz, 1H), 2.77 (d, J = 2.3 Hz, 1H), 2.67 (d,

  17.0 Hz, 1H), 2.53 (s, 3H), 2.46 (s, 3H), 2.43 (s, 3H), 2.36 (s, 3H), 1.78 (s, 15H), 1.70 (bs, 1H), 1.33 (s, 3H), 1.12 (s, 3H). Single crystals suitable for X-ray diffraction were obtained by slow concentration of a pentane solution. ₁₃

  [31,32- C]Cp*HfCl(N ^{2 C 24 H 28 ) (16 13C ) was prepared from 14-THF and 2,3-}

13 Me 2 PhN C in a manner analogous to 16.

  Figure S1. ORTEP view of one enantiomer of the titanaaziridine 3. Thermal

  ellipsoids are drawn at 30% probability level. Selected hydrogen atoms are omitted for clarity. Bond lengths (Å) for this enantiomer: N3 —C41, 1.380(11); N4—C43, 1.290(11).

  REFERENCES

  1. (a) Sheldrick, G. M. SHELXTL, An Integrated System for Solving, Refining, and

  

Displaying Crystal Structures from Diffraction Data, University of Gottingen: Gottingen,

1981; (b) 1333031523 Sheldrick, G., Acta Crystallogr., Sect. A: Found. Crystallogr.

  2008, 64, 112.

  2. (a) 1423599412 Blenkers, J.; Hessen, B.; Vanbolhuis, F.; Wagner, A. J.; Teuben, J.

  H., Organometallics 1987, 6, 459. ; (b) 1434986557 Chen, J.; Kai, Y.; Kasai, N.; Yamamoto, H.; Yasuda, H.; Nakamura, A., Chem. Lett. 1987, 1545. 3. 1434990272 Nanjo, T.; Tsukano, C.; Takemoto, Y., Org. Lett. 2012, 14, 4270. 4. 1433445749 Dunn, S. C.; Mountford, P.; Robson, D. A., J. Chem. Soc., Dalton Trans. 1997, 293. 5. 1423599221 Hessen, B.; Blenkers, J.; Teuben, J. H.; Helgesson, G.; Jagner, S., Organometallics 1989, 8, 830.