Thermodynamics of Hydrogen Atom Transfer to a High-Valent Iron Imido Complex

Abstract

Thermodynamic investigations relevant to hydrogen atom transfer by the high-valent iron imido complex [LMesFe[triple bond]NAd]OTf have been undertaken. The complex is found to be weakly oxidizing by cyclic voltammetry (E1/2 = -0.98 V vs Cp2Fe+/Cp2Fe in MeCN). A combination of experimental and computational studies has been used to determine the acidity of LMesFe-N(H)Ad+ (pKa = 37 in MeCN), allowing the N-H BDFE (88(5) kcal/mol) to be calculated from a thermodynamic cycle. Consistent with this value, [LMesFe[triple bond]NAd]OTf reacts with 9,10-dihydroanthracene (C-H BDE = 78(1) kcal/mol) to form anthracene.

Computational evaluation of tris(carbene)borate donor properties in {NiNO}10complexes

“…[15][16][17] Compared to their monodentate congeners, metal complexes containing multidentate NHCs (e.g. bidentate, [18][19][20][21] tridentate, [22][23][24][25][26][27][28][29][30][31][32][33][34] and tetradentate [35][36][37][38][39][40][41][42] ) have greater versatility in their applications in part due to their greater thermodynamic stability stemming from the chelate effect. Among these are C 3 -symmetric tris(carbene)borate ligands (analogues of tris ( pyrazolyl)borates) and their metal complexes, which have been studied by a number of groups.…”

Formation of Ammonia from an Iron Nitrido Complex

“…[6,7] Reaction of the iron chloride complex [PhB-(MesIm) 3 FeCl] [13] with excess NaN 3 yields the crystallographically characterized azido complex [PhB(MesIm) 3 FeÀN=N= N] (n N=N=N = 2078 cm À1 ), which is then photolyzed to form 1 in high yield. The X-ray crystal structure of 1 shows similar structural features to our related [PhB(tBuIm) 3 Fe N] complex (Scheme 2, inset).…”

Novel scorpionate-type triscarbene ligands and their silver and gold complexes

“…Successively they have modified the tris(carbene)borate class of ligands to incorporate a phenyl group on the boron atom [38]. These bulky tris(carbene)phenylborate ligands are able to stabilize coordinatively unsaturated cobalt(II) centers [38] and to form cobalt(III) [39] and high-valent iron imido complexes [40]. More recently, the same authors have prepared and characterized the manganese(I) tricarbonyl complex of tris(carbene)phenylborate ligands prepared from 1-methylimidazole [41].…”