Coordination of NO2− ligand to Cu(i) ion in an O,O-bidentate fashion that evolves NO gas upon protonation: a model reaction relevant to the denitrification process

Abstract

[(2,6-(Ph(2)P(o-C(6)H(4))CH=N)(2)C(5)H(3)N)(2)Cu(2)](BF(4))(2) (2) has been prepared by treating 2,6-(Ph(2)P(o-C(6)H(4))CH=N)(2)C(5)H(3)N (1) with [Cu(NCMe)(4)]BF(4). Reaction of 2 and [Ph(3)PNPPh(3)]NO(2) produces (2,6-(Ph(2)P(o-C(6)H(4))CH=N)(2)C(5)H(3)N)Cu(NO(2)) (3), with the nitrite ligand in a unique eta(2)-O,O coordination mode. Protonation of 3 releases NO gas, which mimics the reactivity of the Type 2 Cu-NiRs.

CuI complexes containing a multidentate and conformationally flexible dibenzylidene acetone ligand (dbathiophos): Application in catalytic alkene cyclopropanation

“…It is interesting to note that complex 7 acts as a Cu model for the catalytic conversion of nitrite to nitrate. 19 The similar dynamic behaviour and coordination chemistry implies that 4 could also act as a Cu model. Our findings concerning further applications of 1, and the Cu I complexes thereof, will be reported in due course.…”

“…Interestingly, a related cationic Cu I complex, [(2,6-(Ph 2 P(o-C 6 H 4 )CH N) 2 C 5 H 3 N) 2 Cu 2 ](BF 4 ) 2 (7) was reported by Yeh and Chen 19 very recently (Scheme 3). They noted dynamic exchange between the coordinated and the non-coordinated imine groups in solution {DG ‡ = 8.8 kcal mol -1 (36.8 kJ mol -1 ), estimated}.…”

“…An Arrhenius plot of 1/T against ln k gives a straight line with Scheme 3 Dynamic exchange in dinuclear cationic Cu I complex 4 (bottom) and a related reported dinuclear cationic Cu I complex 7 (top). 19 The two anions for each complex are omitted for clarity.…”

Binding and activation of nitrite and nitric oxide by copper nitrite reductase and corresponding model complexes

“…A number of Cu(I)-NO 2 − model complexes have been synthesized and characterized in the literature due to their catalytic activity in nitrite reduction. 11,12,44,52,[54][55][56]73,74 These complexes generally show η 1 -N bound nitrite with typical Cu-N distances of 1.9 Å. 44,45 The first structurally characterized η 1 -N Cu(I)-NO 2 − complex was reported by Tolman and coworker, [Cu(i-Pr 3 TACN)(NO 2 )] (Fig.…”

“…3,8 Additionally, the mechanism for the reduction of NO 2 − to NO by CuNIR is less well understood than that of cd 1 -NIR, and CuNIR is thus the focus of many ongoing investigations. [9][10][11][12][13][14][15][16][17] Copper nitrite reductase (CuNIR)…”