The Synthesis, Crystal, Molecular and Electronic Structure of Trichloro(nitrosyl)bis(triphenyl-Phosphine Oxide)rhenium(ii)

Abstract

A new rhenium nitrosyl complex has been synthesized and characterized by IR, electronic and "P NMR spectroscopy and magnetochemical measurements. Its electronic structure has been determined (Dq = 3333, Ds = -4732 and Dt = 387 cm-'). The crystal and molecular structure of [ReCI3(NO)(OPPh&] has been solved by the heavy atom method and refined anisotropically to R =0.466 for 3032 unique observed reflections. The title compound crystallizes in the monoclinic space group C2/c, with a = 13.887(2), b= 13.154(2), c = 19.629(4)A, p=96.78(2)" and Z = 4. The Re atom is of six-coordinate distorted octahedral configuration and the linear nitrosyl ligand is trans to one of triphenylphosphine oxide molecules. The OPPh3 groups of [ReCI3(NO)(OPPh3)2] are in cis positions.

The reaction of rhenium nitrosyl with a sterically hindered NHC-carbene

“…Re nitrosyls showed extremely good catalytic activity [11][12][13][14][15][16][17][18][19][20] and, as entry point to access the Re-NO complexes, we focused our attention on the well-known Re(V) trans-[(PPh 3 ) 2 ReOCl 3 ] (1), [21][22][23] complex that has shown to react with NO in benzene to give the paramagnetic complex Re(II) [(OPPh 3 ) 2 Re(NO)Cl 3 ] (2). 24 When we attempted the synthesis of complex 2 following a procedure similar to the one reported by Dzie ¸gielewski and co-workers (Scheme 1A), 24 we did get the wanted product 2 but together with the new dinitrosyl Re(I) diamagnetic complex [(OPPh 3 ) 2 Re(NO) 2 Cl 3 ] (3) (Scheme 1B) as confirmed by: FTIR (ESI, Tables S1 and S5 . All these different results could rise from one or more different factors as: type of solvent, amount of solvent used, amount of NO reacted, temperature, reaction time and presence of compounds able to react with NO giving rise even to more effective nitrosating agents.…”

“…Neither in our synthesis (under N 2 ) nor in the case of the synthesis of Dzie ¸gielewski (under Ar) the contact with O 2 took place. 24 It is important to point out that NO reacts with O 2 yielding other two reactive species, i.e., the radical nitrogen dioxide ( • NO 2 ) and the dinitrogen trioxide (N 2 O 3 ). The latter has a structure similar to the Angeli's salt (Na 2 N 2 O 3 ) (Scheme 2).…”

Synthesis, crystal, molecular and electronic structure of rhenium nitrosyl with pyrazole in the coordination sphere

“…The [ReOX 3 L 2 ] compounds (X = Cl and Br, L = PPh 3 , AsPh 3 , 1/2 dppe) easily reacts with gaseous nitric oxide to give a variety of products depending on the reaction conditions: [ReX 3 [17][18][19][20][21][22][23][24][25].…”

“…The rhenium atom is in a distorted octahedral environment with the bromine ligands in meridional geometry and the linear N-O group is trans to the pyrazole molecule and cis to the PPh 3 ligand. The nitrosyl group of the starting complex occupies the trans position to one of the bromine [17][18][19][20][21][22][23][24][25]. The linearly bonded nitrosyl ligand is a poor r-donor and a very strong p-acceptor.…”

“…Due to the favourable nuclear properties of 186 Re and 188 Re nuclides in diagnostic nuclear medicine and radioimmunotherapy, the chemistry of nitrosyl rhenium complexes arouses particular interest [15,16]. [17][18][19][20][21][22][23][24][25].Here, we present the synthesis, spectroscopic characterization, crystal, molecular and electronic structure of a new rhenium nitrosyl with pyrazole (pzH) in a coordination sphere -[ReBr 3 (NO)(PPh 3 )(pzH)]. The electronic 1387-7003/$ -see front matter Ó…”