Alessandra Botter

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

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).

Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives

Mixed-ligand hydride complexes OsHCl(CO)(PPh3)2L (2) [L = P(OMe)3, P(OEt)3] were prepared by allowing OsHCl(CO)(PPh3)3 (1) to react with an excess of phosphite P(OR)3 in refluxing toluene. Dichloro compounds OsCl2(CO)(PPh3)2L (3, 4) were also prepared by reacting 1, 2 with HCl. Treatment of hydrides OsHCl(CO)(PPh3)2L (2), first with triflic acid and then with an excess of RN3 afforded organic azide complexes [OsCl(η(1)-N3R)(CO)(PPh3)2L]BPh4 (5-7) [R = 4-CH3C6H4CH2, C6H5CH2, C6H5; L = P(OEt)3]. Benzylazide complexes react in CH2Cl2/ethanol solution, leading to the imine derivative [OsCl(CO){η(1)-NH═C(H)C6H4-4-CH3}(PPh3)2{P(OEt)3}]BPh4 (8b). Hydrazine complexes [OsCl(CO)(RNHNH2)(PPh3)2L]BPh4 (9-11) [R = H, CH3, C6H5; L = P(OMe)3, P(OEt)3] were prepared by allowing hydride species OsHCl(CO)(PPh3)2L (2) to react first with triflic acid and then with an excess of hydrazine. Aryldiazene derivatives [OsCl(CO)(ArN═NH)(PPh3)2L]BPh4 (12, 13) were also prepared following two different methods: (i) by oxidizing arylhydrazine [OsCl(C6H5NHNH2)(CO)(PPh3)2L]BPh4 (11) with Pb(OAc)4 in CH2Cl2 at -30 °C; (ii) by allowing hydride species OsHCl(CO)(PPh3)2L (2) to react with aryldiazonium cations ArN2(+) (Ar = C6H5, 4-CH3C6H4) in CH2Cl2. The complexes were characterized spectroscopically and by X-ray crystal structure determination of OsHCl(CO)(PPh3)2[P(OEt)3] (2b) and [OsCl{η(1)-NH═C(H)C6H4-4-CH3}(CO)(PPh3)2{P(OEt)3}]BPh4 (8b).

Pentamethylcyclopentadienyl Half-Sandwich Diazoalkane Complexes of Ruthenium: Preparation and Reactivity.

The diazoalkane complexes [Ru(η(5)-C5Me5)(N2CAr1Ar2){P(OR)3}L]BPh4 (1-4) [R = Me, L = P(OMe)3 (1); R = Et, L = P(OEt)3 (2); R = Me, L = PPh3 (3); R = Et, L = PPh3 (4); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c); Ar1 = Ph, Ar2 = PhC(O) (d)] and [Ru(η(5)-C5Me5){N2C(C12H8)}{PPh(OEt)2}(PPh3)]BPh4 (5c) were prepared by allowing chloro-compounds RuCl(η(5)-C5Me5)[P(OR)3]L to react with the diazoalkane Ar1Ar2CN2 in the presence of NaBPh4. Treatment of complexes 1-4 with H2O afforded 1,2-diazene derivatives [Ru(η(5)-C5Me5)(η(2)-NH═NH){P(OR)3}L]BPh4 (6-9) and ketone Ar1Ar2CO. A reaction path involving nucleophilic attack by H2O on the coordinated diazoalkane is proposed and supported by density functional theory calculations. The complexes were characterized spectroscopically (IR and (1)H, (31)P, (13)C, (15)N NMR) and by X-ray crystal structure determination of [Ru(η(5)-C5Me5)(N2CC12H8){P(OEt)3}2]BPh4 (2c) and [Ru(η(5)-C5Me5)(η(2)-NH═NH){P(OEt)3}2]BPh4 (7).

Preparation of diazoalkane complexes of iron(II)

Diazoalkane complexes [Fe(η5-C5H5)(N2CAr1Ar2)(P–P)]BPh4 (1, 2) [P–P = Ph2PCH2CH2PPh2 (dppe) (1), Ph2PCH2CH2CH2PPh2 (dppp) (2); Ar1 = Ar2 = Ph (a); Ar1 = Ph, Ar2 = p-tolyl (b); Ar1Ar2 = C12H8 (c)] were prepared by allowing chloro compounds FeCl(η5-C5H5)(P–P) to react with diazoalkane in the presence of NaBPh4. Phosphine complex [Fe(η5-C5H5)(dppe)(κ1-PPh2CH2CH2PPh2)]BPh4 (3) was also prepared. Treatment of diazoalkane complexes 1, 2 with acrylonitrile afforded 3H-pyrazole derivatives (4, 5), as well as a small amount of nitrile complex [Fe(η5-C5H5)(κ1-NCC(H)CH2)(P–P)]BPh4 (6). The complexes were characterised spectroscopically (IR, NMR) and by X-ray crystal structure determination of [Fe(η5-C5H5){N2C(C12H8)}(dppe)]BPh4 (1c).