The long-term objective of this research is to determine how molecular nitrogen can be reduced to ammonia catalytically under ambient conditions employing a well-defined transition metal complex, protons, and electrons. The short-term objective is to investigate the chemistry of relatively high oxidation state complexes of (primarily) Mo or W that contain trianionic triamido/donor and related ligands, especially chemistry that is relevant to the reduction of dinitrogen, including the chemistry of complexes that contain N2Hx (x = 0.4) or NHy (Y = 0-3) ligands. We wish to determine what principles are of fundamental and general significance to the reduction of dinitrogen to ammonia. In the process we also want to remain open to the possibility of """"""""fixing"""""""" dinitrogen in the form of some nitrogen..containing organic molecule, at first stoichiometrically, and ultimately catalytically. Specifically, we first want to prepare and study complexes that contain Mo or W and known triamidoamine ligands, [(RNCH2CH2)3N]3- (R = trialkylsilyl, C6F5). We then want to prepare potentially more stable variations in which R is (e.g.) CH(CF3)2 or C(C6H5)(CF3)2. Analogous ligand systems that contain P or As donors in place of N will also be prepared and attached to Mo and W in order to address the issue of apical donor ligand binding. Other variations will also be explored, including tridentate trianionic ligands such as ([RNC(SiMe3)2]3CR')3- and tribenzimidazolatoamine ligands. Finally we want to synthesize related complexes in which dinitrogen could be bound and reduced within a """"""""cage"""""""" or """"""""cavity,"""""""" a circumstance that would eliminate the problem of bimolecular decomposition of intermediates in the dinitrogen reduction process by inorganic complexes in solution.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Massachusetts Institute of Technology
Schools of Arts and Sciences
United States
Zip Code
Sharma, Ajay; Roemelt, Michael; Reithofer, Michael et al. (2017) EPR/ENDOR and Theoretical Study of the Jahn-Teller-Active [HIPTN3N]MoVL Complexes (L = N-, NH). Inorg Chem 56:6906-6919
Kinney, R Adam; McNaughton, Rebecca L; Chin, Jia Min et al. (2011) Protonation of the dinitrogen-reduction catalyst [HIPTN3N]Mo(III) investigated by ENDOR spectroscopy. Inorg Chem 50:418-20
Kinney, R Adam; Hetterscheid, Dennis G H; Hanna, Brian S et al. (2010) Formation of {[HIPTN(3)N]Mo(III)H}(-) by heterolytic cleavage of H(2) as established by EPR and ENDOR spectroscopy. Inorg Chem 49:704-13
McNaughton, Rebecca L; Roemelt, Michael; Chin, Jia Min et al. (2010) Experimental and theoretical EPR study of Jahn-Teller-active [HIPTN(3)N]MoL complexes (L = N(2), CO, NH(3)). J Am Chem Soc 132:8645-56
Chin, J M; Schrock, R R; Müller, P (2010) Synthesis of diamidopyrrolyl molybdenum complexes relevant to reduction of dinitrogen to ammonia. Inorg Chem 49:7904-16
Reithofer, Michael R; Schrock, Richard R; Müller, Peter (2010) Synthesis of [(DPPNCH2CH2)3N]3- molybdenum complexes (DPP = 3,5-(2,5-Diisopropylpyrrolyl)2C6H3) and studies relevant to catalytic reduction of dinitrogen. J Am Chem Soc 132:8349-58
Hetterscheid, Dennis G H; Hanna, Brian S; Schrock, Richard R (2009) Molybdenum triamidoamine systems. Reactions involving dihydrogen relevant to catalytic reduction of dinitrogen. Inorg Chem 48:8569-77
Kupfer, Thomas; Schrock, Richard R (2009) Alkylation of dinitrogen in [(HIPTNCH(2)CH(2))(3)N]Mo complexes (HIPT = 3,5-(2,4,6-i-Pr(3)C(6)H(2))(2)C(6)H(3)). J Am Chem Soc 131:12829-37
Schrock, Richard R (2008) Catalytic reduction of dinitrogen to ammonia by molybdenum: theory versus experiment. Angew Chem Int Ed Engl 47:5512-22
McNaughton, Rebecca L; Chin, Jia Min; Weare, Walter W et al. (2007) EPR study of the low-spin [d(3);S =(1)/(2)], Jahn-Teller-active, dinitrogen complex of a molybdenum trisamidoamine. J Am Chem Soc 129:3480-1

Showing the most recent 10 out of 23 publications