This document summarizes two experiments involving boron hydrides. The first synthesized tertbutylammonium borohydride (ButNH2BH3) which was characterized using 1H NMR, IR spectroscopy, and yielded 50.6%. The second synthesized bis(triphenylphosphine)borohydridocopper(I) [(PPh3)2CuBH4] which was also characterized using 1H NMR, 31P NMR, and IR spectroscopy. Decomposition products of [(PPh3)2CuBH4] were analyzed using 1H NMR, 31P NMR and IR spectroscopy. 11B NMR was also used to analyze the first product and residue. In summary, the document demonstrated the synthesis

1. EXPERIMENT B33:
REACTIONS OF BORON HYDRIDES
Presented by Paul Kirkpatrick

2. FIRST SYNTHESIS:
Synthesis of Tertbutylammonium Borohydride (ButNH2BH3)

3. EXPERIMENTAL:
STEP ONE: Turn on the THF!
Figure 1. Gaseous HCl
blown through t-butylamine
Figure 2. Sodum
Borohydride Added,
Stirred for Two Hours

4. EQUATIONS:
SYNTHESIS OF AMINE-BORANES, A VARIATION OF THE NAINAN EXPERIMENT1

5. Table 1. 1H nmr Data for ButNH2BH3 Product
50.6 % Yield, Positive 1H nmr, IR
ppm Multiplicity Integration Assignment Literature1
7.19 s Chloroform
3.50 s 2 H Ha
1.24 s 12 H Hb ppm = 1.25 for
(CH3)2CHNH2BH3
RESULTS:
Figure 5. 1H nmr of ButNH2BH3

6. Table 11. 1H nmr Data for ButNH2BH3 Product
Product
50.6 % Yield, Positive 1H nmr, IR
RESULTS:
Figure 11. IR of ButNH2BH3
Wavenumber
/ cm-1
Relative
Intensity
Assignment and
Comment
Literature2
3311 medium N-H stretching,
secondary amine
3267 medium N-H stretching,
secondary amine
2390 medium B-H stretch,
borohydride
2385 cm-1 B-H
stretching
2330 medium B-H stretch,
borohydride
2353 cm-1 B-H
stretching

7. SECOND SYNTHESIS:
Synthesis of Bis(triphenylphosphine)borohydridocopper(I) [(PPh3)2CuBH4]

8. EXPERIMENTAL
Figure 7. Copper Sulfate Pentahydrate

9. EXPERIMENTAL
Figure 7. Copper Sulfate Pentahydrate Figure 8. Dissolved in Ethanol With TPP

10. EXPERIMENTAL
Figure 7. Copper Sulfate Pentahydrate Figure 9. With Added NaBH4Figure 8. Dissolved in Ethanol With TPP

11. EXPERIMENTAL
Figure 7. Copper Sulfate Pentahydrate Figure 9. With Added NaBH4Figure 8. Dissolved in Ethanol With TPP Figure 10. Filtered Product in Bruckner
Funnel, Dropped in Chloroform

12. EQUATIONS:
SYNTHESIS OF BOROHYDRIDE COMPLEX

13. Table 3. 1H nmr Data for [(PPh3)2CuBH4] Product
ppm Multiplicity J (Hz) Integration Assignment Literature1.
7.34 Multiplet 12 H Ha Ppm = 7.47
for
(C6H5)PBH3
7.29 t 1.34, 7.19 2 H Hc
7.27 t 2.40, 7.33 2 H Hc
7.24 t 1.50, 7.47 2 H Hc
7.19 s 7.78 4 H Hb
7.16 s 7.36 4 H Hb
7.14 s 6.88 4 H Hb
3.65 q 8.88
3.41 q 7.08
1.48 s 2 H Hd
1.27 s
1.17 t 7.03 2 H He

14. Figure 7. Expanded Aromatic Region of1H nmr for
[(PPh3)2CuBH4] Product
EXPANDED AROMATIC REGION

15. Table 4. 31P nmr Data for [(PPh3)2CuBH4] Product
31P nmr conforms to expected
value as given in lab manual
RESULTS:
Figure 10. 31P nm of [(PPh3)2CuBH4]
ppm Assignment Literature3.
-3.17 Phosphorus PPh3 = -5 ppm,
O=PPh3 = +24 ppm

16. Table 5. IR Data for [(PPh3)2CuBH4] Product
Confirm IR Results of Davidson2.
RESULTS:
Wavenumber
/ cm-1
Relative
Intensit
y
Assignment
and Comment
Literature2.
2403 medium B-H stretch,
borohydride
2385 cm-1 B-H
stretching
2403 medium B-H stretch,
borohydride
2353 cm-1 B-H
stretching
Figure 10. Nujol IR of [(PPh3)2CuBH4]

17. SUMMARY:
• Both Products Synthesized
• Characterized by Basic Spectroscopic Methods

18. NEXT:
• Decomposition Products
• 11B nmr

19. Figure 11. 0.5 g Triphenylphosphine
Copper Complex Before Burning (Left)
and After (Right)
Figure 12. Overall Reaction of
Copper Complex in Oxygen and
Heat
Decomposition Products

20. FILTRATE ANALYSIS:
• No peak observed at 7.47 ppm for aromatic, or ~1.25 for alkane as
seen in Davidson paper
• No peak observed at -5 ppm as expected by lab manual
• IR Data shows strong peaks at 1463 cm-1 and 1377 cm-1 as expected
with Nujol
• No peak at 1436 cm-1 or 693 cm-1 for
triphenylphosphine

21. Figure 11. IR Spectrum for Triphenylphosphine Filtrate in Nujol Figure 12. IR Spectrum for Triphenylphosphine Obtained from SDBS.
IR of Filtrate (Left) Compared to IR of PPh3 Courtesy SDBS

22. RESIDUE ANALYSIS:
• Same peaks missing in 1H nmr and 31P nmr as above (See Tables 11
and Table 12 in Supplementary Data/Report or Previous Slide)

23. RESIDUE ANALYSIS:
• Same peaks missing in 1H nmr and 31P nmr as above (See Tables 11
and Table 12 in Supplementary Data/Report or Previous Slide)
• However, IR peaks revealed B-H Stretching at 2402 cm-1 and 2325
cm-1
Figure 13. Expansion of BH peaks
on IR Spectrum in Nujol

24. IN 2001, IUPAC SET NEW STANDARDS FOR
RERENCING NMR: USING TMS
(TETRAMETHYLSILANE) AS INTERNAL STANDARD
THE EQUATION USED WITH 11B NMR
IN THIS EXPERIMENT IS SHOWN
ABOVE, WITH A MODIFICATION FOR
SPECTROMETER FREQUENCY (SF)
OR APPLIED FREQUENCY (RIGHT)

25. FINALLY, B DATA SHOWED EXPECTED SPECTRA
FOR BORON GROUPS IN FIRST PRODUCT AND
RESIDUE:
ppm Multiplicity Assignment Literature1.
32.0832424 s Boron ppm=38.5 for
(CH3)2CHNH2B
H3
Figure 14. 11B{1H} nmr Data for ButNH2BH3

26. IN SUMMARY:
• Demonstrated amine donation to borohydride to make ButNH2BH3, a
precursor in borane synthesis
• Synthesized [(PPh3)2CuBH4]
• Proved presence of both products using IR and 1H, 31P, and 11B nmr
• Filtrate and residue analysis came up negative, except for IR on
residue which confirmed presence of BH group
• Conclusion? Newer analytical methods can complement older ones,
and both can be useful in boron hydride synthesis

27. REFERENCES
1.) Nainan, K.C.; Ryschkewitsch, G.E. Inorg. Chem., 1969, 8, 2671
2.) Davidson, J.M. Chem. Ind. (London), 1964, 2021
3.) Berry, D, Chemistry 362 Laboratory Manual, University of Victoria (2016) p A5-1-A5-3
4.) Wikipedia. Herman Irving Schlesinger. < https://en.wikipedia.org/wiki/Hermann
_Irving_Schlesinger> Updated 13 March 2016. Accessed 24 March 2016.
5.) Schubert, D. Kirk-Othmer Encyclopedia of Chemical Technology (Online) 2004
http://onlinelibrary.wiley.com/doi/10.1002/0471238961.0215181519030821.a01/abstract;jsessionid=4
4C1107DE71A8DC9F7A4B33D25C1CC26.f01t01 Accessed: 24 March 2016.
6.) Brock, W.H; Jensen, K.A.; Jørgensen, C.K.; Kauffman, G.B.; Polyhedron 1983 2,1,1-7