Hydrolysis of Coordinated Diazoalkanes To Yield Side-On 1,2-Diazene Derivatives

Abstract

Diazoalkane complexes [Ru(η(5)-C5Me5)(N2CAr1Ar2)(PPh3){P(OR)3}]BPh4 [R = Me (1), Et (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c)] were prepared by allowing chloro complexes RuCl(η(5)-C5Me5)(PPh3)[P(OR)3] to react with diazoalkane Ar1Ar2CN2 in ethanol. The treatment of compounds 1 and 2 with H2O afforded 1,2-diazene derivatives [Ru(η(5)-C5Me5)(η(2)-NH═NH)(PPh3){P(OR)3}]BPh4 (3 and 4) and ketone Ar1Ar2CO. A reaction path involving nucleophilic attack by H2O on the coordinated diazoalkane is proposed. The complexes were characterized spectroscopically (IR and NMR) and by X-ray crystal structure determination of [Ru(η(5)-C5Me5)(η(2)-NH═NH)(PPh3){P(OMe)3}]BPh4 (3).

Ruthenium Complexes for Catalytic Dehydrogenation of Hydrazine and Transfer Hydrogenation Reactions

“…Hydrazine coordinated transition metal complexes have been receiving huge scientific attention because of the involvement of metal‐hydrazine species as important intermediates in several reactions of global importance including nitrogen to ammonia reduction . Therefore, such hydrazine coordinated complexes based on Fe, W, Mo, Ir, Ru and others have been extensively explored for diverse applications (Figure ) . For instance, Tyler et al.…”

“…num-terpyridine-phosphine in [( Ph Tpy)(PPh 2 Me) 2 Mo(k 2 -N 2 H 4 )] complex. [26] Field et al also investigated the base-induced dehydrogenation of hydrazinev ia a "coordination induced activation pathway" over Ru-tetradentate phosphine complexes, where ligand exerted significant impact on the coordination of hydrazinet oR u( side-on [RuCl(k 2 -N 2 H 4 )(k 3 -PP 3 ipr )] + or end-on bound hydrazine [RuCl(k 1 -N 2 H 4 )(k 4 -PP 3 Ph )] + )a nd the reactivity pathway of the resultingc omplexes. [27] Apart from homogeneous catalysts there are several reports availablei nl iterature for the dehydrogenation of hydrazine using heterogeneousc atalysts but exploration of homogeneous complexes for hydrazine activation is of particulari mportanceb ecause of several applications.…”

Diazoalkane complexes of ruthenium with tris(pyrazolyl)borate and bis(pyrazolyl)acetate ligands

“…[1][2][3][4][7][8][9][10] In addition, diazoalkane complexes may be of interest as models for understanding N 2 coordination and functionalisation. 11,12 A number of diazoalkane complexes of several metals have been reported [1][2][3][4][7][8][9][10] and their reactivity studies have highlighted various pathways, depending on the coordination mode and the nature of ancillary ligands. Thus, extrusion of dinitrogen with carbene formation was observed in η 2 -CN-coordinated species, 4f,5,6 whereas an η 1 -N-bound diazoalkane can yield dinitrogen [M]-N 2 complexes, 4f convert carbene to imine, 5f or cleave the N-N bond of the N 2 CAr1Ar2 group.…”

“…4g Dipolar (3 + 2) cycloaddition of coordinated diazoalkane with alkene and alkyne, affording 3H-pyrazole derivatives, 8 as well as hydrolysis, yielding η 2 -diazene derivatives has recently been reported. 9 In recent years, we have been interested in the chemistry of diazoalkane complexes [7][8][9][10]13 and have reported the synthesis and reactivity of these types of compounds having p-cymene, η 5 -C 5 H 5 , η 5 -C 5 Me 5 and indenyl as supporting ligands. As the reactivity of the coordinated N 2 CAr1Ar2 group in these complexes is strongly influenced by the nature of ancillary ligands, we thought of extending our study to the comparable tris( pyrazolyl)borate (Tp) ligand, 14 to test whether stable diazoalkane complexes could be prepared and to understand how their properties changed.…”

Reactions of Iron(II) Complexes Supported by Tripodal Amido-Phosphine-Amido Ligands with Diazo Compounds

“…[6][7][8][9][10] Consequently, there are great interests on the sythesis, structural feature, and reactivity of transition-metal diazoalkane complexes. The known transition-metal diazoalkane complexes are dominated by the complexes of cobalt, nickel, and ruthenium, [11][12][13][14][15][16] whereas the diazoalkane complexes of iron are scarce, which form a sharp contrast to the soaring research interest on iron-catalyzed carbenetransfter reactions. [17] The limited examples of iron diazoalkane complexes include the bis(imino)pyridine complex [(PDI)Fe(η 1 -N 2 CH-SiMe 3 )] (A in Chart 1), [18] the tris(pyrrolido)ethane iron complex [(tpe)Fe(η 1 -N 2 CPh 2 )][Li(THF) 4 ] (tpe＝tris(5-mesitylpyrrolyl)ethane, B), [19] the β-diketiminate iron complex [L Bu-t Fe(η 1 -N 2 CPh 2 )] (L Bu-t ＝ [(DippNCBu t ) 2 CH] -, C) [20] , the cyclopentadienyliron complexes [(η 5 -C 5 H 5 ) Fe(η 1 -N 2 C-Ar 1 Ar 2 )(P-P)]BPh 4 (P-P＝1,2-bis(diphenylphosphine)ethane, 1,3-bis(diphenylphosphine)propane; Ar 1 ＝ Ar 2 ＝ Ph; Ar 1 ＝Ph, Ar 2 ＝p-tolyl; Ar 1 Ar 2 ＝C 12 H 8 , D), [21] as well as the side-on type diazo complexes [(PDI)Fe(η 2 -N,N-N 2 C-Ph 2 )] (E) [22] and [L Bu-t Fe(η 2 -N,N-N 2 CPh 2 )K(OEt 2 )] 2 (F) [20] .…”