Transition Metal Complexes of Diazonium Salts as Models for Nitrogenase

Bioinorganic chemistry. Simple models of iron sites in some biological systems

“…Many workers have discussed model systems which reduce acetylene (65, 67), since the enzyme itself reduces acetylene (53), however it now appears that acetylene may occupy a different site to dinitrogen in the reduction process (68). The most significant work to date has shown that dinitrogen may be reduced to ammonia in aqueous solution in the presence of Work with aryldiazonium salts (Ar-N +=N) as models for metal dinitrogen complexes (M--NsN) has given rise to a variety of proposals (53,70), including the possible involvement of an N4 entity ( 70). An-other possibility which cannot be excluded is the bridging of the dinitrogen unit through only one nitrogen atom, as a compound containing bridging N2H groups is known (71).…”

“…An-other possibility which cannot be excluded is the bridging of the dinitrogen unit through only one nitrogen atom, as a compound containing bridging N2H groups is known (71). Most researchers seem to have taken for granted that the dinitrogen bonds to metals, though evidence is mounting that a non-metal may well be one of the bonding atoms (70). Continuing the diazonium analogy, it is found that aryldiazonium salts react rapidly with thiols (72), and in the biological system, it appears that -SH groups not coordinated to the iron atom play a special role in the fixation process (73).…”

Coordination of the aryldiazo ligand to transition metals. Structure of chloro(bis(3-diphenylphosphinopropyl)phenylphosphine)phenyldiazorhodium hexafluorophosphate ethylene chloride solvate

“…The crystal packing is dominated by nonbonded interactions involving the bulky cations which are situated about the lattice points (000). The 2) 35 (1) 24 (2) 11 (1) 9 (1) P(2) -0.0182 (2) -0.2715 (2) 0.2775 (2) 83 (2) 56 ( 2) 44 ( 1) 27 (2) 9 (1) 14 (1) P( 3 2) 27 (2) 26 (2) 9 (2) N(l) 0.1676 (6) -0.0266 (6) 0.3409 ( 5) 89 ( 8) 74 ( 7) 48 ( 5) 35 (6) 8 ( 5) 13 (4) N(2) 0.2121 (7) -0.0657 (6) 0.3941 ( 5) 112 ( 9) 88 ( 7) 46 (51 40 (7) 3 (5) 6 (5)…”

“…(2) Á off-axis in [RhLCl(N2Ph)] + compared with 0.33 (2) Á off-axis in [RhLCl(NO)]+. The major differences that exist occur in the interatomic angles within the coordination spheres of the two complexes.…”

Structural studies of bridged lanthanide(III) complexes. Diaquotri(nicotinic acid)holmium(III) hexa(isothiocyanato)chromate(III) dihydrate and diaquotris(isonicotinato)lanthanum(III)

“…The coordination of trivalent rare earth ions with the carboxylate and carbonyl functional groups has been the subject of a number of studies. [3][4][5][6][7][8] Chupakhina and Serebrennikov3•4 5have described the preparation and properties of the trivalent lanthanide complexes with nicotinic acid (pyridine-3-carboxylic acid) and the nicotinate anion (pyridine-3-carboxylate). These compounds were formulated as [Ln(C5H4NHCOO)3] [Cr(NCS)e] and [Ln(C6H4NCOO)3].…”