Preparation of Diethylcyanamide and Cyanoguanidine Complexes of Iridium

Abstract

Diethylcyanamide [IrCl(η5‐C5Me5)(N≡CNEt2){P(OR)3}]BPh4 (1) and cyanoguanidine complexes [IrCl(η5‐C5Me5){N≡CN(H)C(NH2)=NH}{P(OR)3}]BPh4 (2) were prepared by allowing chloro compounds [IrCl2(η5‐C5Me5){P(OR)3}] to react with an excess of cyanamide or cyanoguanidine, respectively. Alternatively, complexes 2 were prepared by reacting [IrCl2(η5‐C5Me5){P(OR)3}] with an excess of cyanamide N≡CNH2. Bis(diethylcyanamide) [Ir(η5‐C5Me5) (N≡CNEt2)2{P(OR)3}](BPh4)2 (3) and bis(cyanoguanidine) derivatives [Ir(η5‐C5Me5){N≡CN=C(NH2)2}2{P(OR)3}](BPh4)2 (4) were also prepared by treating dichloro precursors [IrCl2(η5‐C5Me5){P(OR)3}] first with two equivalents of AgOTf and then with an excess of diethylcyanamide or cyanoguanidine, respectively. The compounds were characterised spectroscopically (IR and NMR) and by X‐ray crystal structure determination of [Ir(η5‐C5Me5)(N≡CNEt2)2{P(OMe)3}](BPh4)2.

Elucidation of the Reaction Mechanism of C2 + N1 Aziridination from Tetracarbene Iron Catalysts

“…An iron imide could be formed through initial binding of the α-nitrogen or γnitrogen of the azide to the catalyst, so both intermediates were investigated. [59][60][61][62][63] Similar to Co and Ru systems, the energy of the α-bound intermediate was lower than that of the γbound case. 39,40,64 The free energy of activation for formation of the imide from the αbound intermediate was calculated to be ΔG ‡ = 9.9 kcal/mol, suggesting that the formation of imide via this route is highly facile at room temperature (rt) (no route to an imide was found for the γ-bound case).…”

Stannyl Complexes of Rhodium and Iridium: Preparation of Mono‐ and Bis(trihydridestannyl) Derivatives

“…The centroid of Cp* ligand is situated at 1.875(2) Å from the iridium atom, and the average Ir–C bond distances for the Cp* ligand is 2.238 Å, being both values similar to those found in the literature, as for example in the cations [Cp*IrCl(NH 2 NH 2 ){P(OEt) 3 }] + and [Cp*IrCl(CH 3 NHNH 2 ){P(OEt) 3 }] + , or in [Cp*Ir{η 1 ‐C 6 H 5 (H)C=N–N=C(H)(C 6 H 5 )} {P(OMe) 3 }] + , or also in [Ir(η 5 ‐C 5 Me 5 )(N≡CNEt 2 ) 2 {P(OMe) 3 }] 2+ . However, it is noteworthy the wide range of the Ir–C bonds, from 2.213(5) to 2.263(5) Å, longest values, Ir–C(4) and Ir–C(5), quasi‐trans to the phosphite ligand, as can be seen in the small inset in Figure .…”

Synthesis and Characterization Complexes of Ni(II) that Contain Cyanoguanidine and Phosphines Ligands

“…Based on the results obtained and compared with the literature [26,27], we suggest the following formulas for the prepared complexes: 1-The complex [Ni(Cy)2Cl2] (1) shall be a tetrahedral where ligand Cy is coordinate by the (C≡N) group.…”