The Secret History of DMeOPrPE · 10/15/2014 · T 1 (min) Correlation Times in ms •H 2 = 1600...
Transcript of The Secret History of DMeOPrPE · 10/15/2014 · T 1 (min) Correlation Times in ms •H 2 = 1600...
The Secret
History of DMeOPrPEAlexander J. Kendall
D. R. Tyler Laboratories
Group Meeting 10/15/2014
The Secret
History of DMeOPrPEAlexander J. Kendall
D. R. Tyler Laboratories
Group Meeting 10/15/2014
Outline•Synthesis
• Iron ComplexesN2 activation
N2 reduction intermediates
H2 activation
•Ru ComplexesH2 activation
H2O coordination
H-bonding of H2
•Future of DMeOPrPE
Background: Synthesis
•1,2-bis(bis(methoxypropyl)phosphino)propane
tmepe – tetra(methoxypropyl) bis(phosphino)ethane
• 99mTc complexes
Bidentate for metal-complex stability
Lipophillic and hydrophillic
Herbowski, A.; Deutsch, E. A. J. Organomet. Chem. 1993, 460, 19-23.
Background: Tyler Lab
•1,2-bis(bis(methoxypropyl)phosphino)propane
DMeOPrPE – bis(dimethoxypropylphosphino)ethane
Miller, W. K.; Gilbertson, J. D.; Leiva-Paredes, C.; Bernatis, P. R.; Weakley, T. J. R.; Lyon, D. K.; Tyler, D. R. Inorg. Chem. 2002, 41, 5453-5465.c
Debut in Inorganic Literature
•Precursors to water-soluble dinitrogen carriers
•Water-soluble iron(II) complexes for small molecule activation
RSO3- groups non-innocent
Bidentate only ligands
Miller, W. K.; Gilbertson, J. D.; Leiva-Paredes, C.; Bernatis, P. R.; Weakley, T. J. R.; Lyon, D. K.; Tyler, D. R. Inorg. Chem. 2002, 41, 5453-5465.c
Someone Crystalized This
Miller, W. K.; Gilbertson, J. D.; Leiva-Paredes, C.; Bernatis, P. R.; Weakley, T. J. R.; Lyon, D. K.; Tyler, D. R. Inorg. Chem. 2002, 41, 5453-5465.
DEMeOPrOPE and Dinitrogen
•Heterolysis of H2
•Coordination of N2
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
Metal-H2 Complexes
•XRD
• IR
• 15N NMR
DEMeOPrOPE and Dinitrogen
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
“Free N2”: vNN = 2331 cm-1
DEMeOPrOPE and Dinitrogen
•Reductive deprotonation provides
Fe(0)-N2 complex
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
DEMeOPrOPE and Dinitrogen
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
DEMeOPrOPE and Dinitrogen
•Protonation of Fe(0)-N2
provides small yields of
NH3
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
DEMeOPrOPE and Dinitrogen
•Protonation of Fe(0)-N2
provides small yields of
NH3
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
Speculative Mechanism of N2 Reduction
•Fe(N2)Fe dimer to N2H4
•Fe(N2) to N2H2
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc., 2005, 127, 10184-10185.
N2 Reduction Intermediates: Pathway
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2007, 46, 10476-10478.
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2007, 46, 10476-10478.
Barney, B. M.; Laryukhin, M.; Igarashi, R. Y.; Lee, H.; Dos Santos, P. C.; Yang, T.; Hoffman, B. M. Dean, D. R.;
Seefeldt, L. C. Biochemistry, 2005, 44, 8030-8037. : Barney, B. M.; Yang, T.; Igarashi, R. Y.; Dos Santos, P. C.;
Laryukhin, M.; Lee, H.; Hoffman, B. M.; Dean, D. R.; Seefeldt, L. C. J. Am. Chem. Soc., 2005, 127, 14960-14961.
[Fe(P2)2N2H4][2 NaBPh4]
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2007, 46, 10476-10478.
Barney, B. M.; Laryukhin, M.; Igarashi, R. Y.; Lee, H.; Dos Santos, P. C.; Yang, T.; Hoffman, B. M. Dean, D. R.;
Seefeldt, L. C. Biochemistry, 2005, 44, 8030-8037. : Barney, B. M.; Yang, T.; Igarashi, R. Y.; Dos Santos, P. C.;
Laryukhin, M.; Lee, H.; Hoffman, B. M.; Dean, D. R.; Seefeldt, L. C. J. Am. Chem. Soc., 2005, 127, 14960-14961.
[Fe(P2)2N2H4][2 NaBPh4]
First η2 coordination of hydrazine to iron
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2007, 46, 10476-10478.
N2 Reduction Intermediates: Pathway
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2007, 46, 10476-10478.
N2 Reduction Intermediates: N2H4
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
[Fe(H)(P2)2N2H4][NaBPh4]
N2 Reduction Intermediates: N2H2
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: N2H2
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: N2H2
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: N2H2
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
N2 Reduction Intermediates: Characterized
Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Inorg. Chem., 2011, 51, 439-445.
•Mechanism still not well understood
Fe Complexes: H2 Activation in H2O
•Heterolysis of H2 in water
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
pKa(1)= 8.2
pKa(2)= 5.4
Fe Complexes: H2 Activation in H2O
•Heterolysis of H2 in water
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
pKa(1)= 8.2
pKa(2)= 5.4
Metal-H2 Complexes
•Neutron diffraction
• IR
•NMR
0.8 Å < H-H bond < 1.2Å 1.2 Å < H-H bond
0.74 Å = Free H-H bond
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
Isotopologue Measurement: 1JHD
•Through-bonding interaction
• 1JHH is 0; H-H magnetically equivalent nuclei
•Smaller J values = longer bond; weaker bond
Claridge, T. D. W. High-Resolution NMR Techniques in Organic Chemistry, Volume 27, Second Edition; 2 edition.; Elsevier Science, 2004.
HD(g) 43.2 Hz
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
T1 Correlation Times
•T1 = spin-lattice relaxation time
The average lifetime of nuclei in the higher energy
state
Dependent on the gyromagnetic ratio of the nucleus
and the mobility of the lattice
As mobility increases, the vibrational and rotational
frequencies increase
Claridge, T. D. W. High-Resolution NMR Techniques in Organic Chemistry, Volume 27, Second Edition; 2 edition.; Elsevier
Science, 2004.
Hamilton, D. G.; Crabtree, R. H. J. Am. Chem. Soc., 1988, 110, 4126-4133.
Desrosiers, P. J.; Cai, L.; Lin, Z.; Richards, R.; Halpern, J. J. Am. Chem Soc.1991, 113, 4173-4184.
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
T1 Correlation Times
•T1 = spin-lattice relaxation time
The average lifetime of nuclei in the higher energy
state
Dependent on the gyromagnetic ratio of the nucleus
and the mobility of the lattice
As mobility increases, the vibrational and rotational
frequencies increase
Claridge, T. D. W. High-Resolution NMR Techniques in Organic Chemistry, Volume 27, Second Edition; 2 edition.; Elsevier
Science, 2004.
Hamilton, D. G.; Crabtree, R. H. J. Am. Chem. Soc., 1988, 110, 4126-4133.
Desrosiers, P. J.; Cai, L.; Lin, Z.; Richards, R.; Halpern, J. J. Am. Chem Soc.1991, 113, 4173-4184.
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
T1 Correlation Times
T1 Minimum
“T1 will go through a minimum when the
Brownian motion (measured by a
rotational correlation time, τc) is
matched with the Larmor frequency,
ω… If we can observe the T1 minimum
experimentally we will know τc at that
temperature.”
Hamilton, D. G.; Crabtree, R. H. J. Am. Chem. Soc., 1988, 110, 4126-4133.
T1 (min) Correlation Times in ms
•H2 = 1600
• (H)2Fe(CO)4 = 3000
•Os(H)4(P(p-Tol)3)3 = 820
• [IrH(H2)(bq)(PPh3)]+ = 30, 390
•Fe(H2)H2(PEtPh2)3 = 24
Claridge, T. D. W. High-Resolution NMR Techniques in Organic Chemistry, Volume 27, Second Edition; 2 edition.; Elsevier
Science, 2004.
Hamilton, D. G.; Crabtree, R. H. J. Am. Chem. Soc., 1988, 110, 4126-4133.
Desrosiers, P. J.; Cai, L.; Lin, Z.; Richards, R.; Halpern, J. J. Am. Chem Soc.1991, 113, 4173-4184.
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
M(H2)
T1 ~ 4-100 ms
M(H)(H)
T1 >> 100 ms
Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. Inorg. Chem. 2004, 43, 3341-3343.
Fe-H2 Activation
•DMeOPrPE complexes of Fe(II)
Hetrolysis of H2 in water (2 e- from H2)
Activate N2 for reduction
Non-classical H2 ligand
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Ruthenium H2 Activation
Ru-H2 Mechanism: Top Route
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Ru-H2 Mechanism: Top Route
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Ru-H2 Mechanism: Bottom Route
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Ru-H2 Mechanism: Bottom Route
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Ruthenium H2 Activation
Aqueous Chemistry of H2
•Why the difference in H2O reactivity?
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
Thermodynamic Explanation
Kinetic Explanation
“If reacting M-L bond is strengthened, a higher activation
barrier generally results, regardless of the energy of the
products. Accordingly, a more highly donating phosphine
ligand such as DEPE and DMeOPrPE will contribute to a
higher activation barrier for ligand substitution. This may
explain the lack of H2O substitution in the case of the more
electron-donating phosphine ligands.”
•DFT: Near thermodynamic neutrality
Neither favored nor disfavored
Szymczak, N. K.; Braden, D. A.; Crossland, J. L., Yevgeniya, T.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem., 2009, 48, 2976-2984.
H2 Hydrogen Bonding in H2O
•H2 H-bonding accounts for stronger H2 binding
Difficult to quantify due to weak interactions
Ion pairing energies
Crystal packing forces
Solvation
Easy to displace H2 with CO, tBuCN, PMe3
Difficult to displace with H-bonding ligands (OH2)
Stable for months in H2O without H2 atmosphere
Szymczak, N. K.; Zakharov, L. N.; Tyler, D. R. J. Am. Chem. Soc. 2006, 128, 15830-15835.
Measuring a H2 H-Bond
• 1JHD with H-bonding acceptor show no
significant changes
• IR with H-bonding acceptor not sensitive
enough
•T1 (min) measurements
Szymczak, N. K.; Zakharov, L. N.; Tyler, D. R. J. Am. Chem. Soc. 2006, 128, 15830-15835.
Measuring a H2 H-Bond
• 1JHD with H-bonding acceptor show no
significant changes
• IR with H-bonding acceptor not sensitive
enough
•T1 (min) measurements
Szymczak, N. K.; Zakharov, L. N.; Tyler, D. R. J. Am. Chem. Soc. 2006, 128, 15830-15835.
τc of the H-Bond Acceptor
Szymczak, N. K.; Zakharov, L. N.; Tyler, D. R.J. Am. Chem. Soc. 2006, 128, 15830-15835.
•Viscous solvent
• Internal rotational
standard (cyHex-d12)
•H2 isolated as H-bonder
via CO derivative
τc of the H-Bond Acceptor
Szymczak, N. K.; Zakharov, L. N.; Tyler, D. R.J. Am. Chem. Soc. 2006, 128, 15830-15835.
•Viscous solvent
• Internal rotational
standard (cyHex-d12)
•H2 isolated as H-bonder
via CO derivative
Summary and Conclusions
• DMeOPrPEWater soluble, strong sigma-donating ability, innocent ligand
• Fe(II) complexesCoordinate and reduce N2
Intermediate reduction complexes are promising
Heterolysis of H2
• Ru(II) complexesExcellent H2 activation
Inertness to H2O Substitution
H-Bonding to H2O in solution
Invented a new H-bonding detection method
DMeOPrPE
Kendall, A. J. The Secret History of the DMeOPrPE; Reprint edition.; Overlook TP: Woodstock, NY, 2014.