Transformations in Transition-Metal Carbonyls Containing Arsenic: Exploring the Chemistry of [Et₄N]₂[HAs{Fe(CO)₄}₃] in the Search for Single-Source Precursors for Advanced Metal Pnictide Materials

Abstract

The chemistry of [Et 4 N] 2 [HAs{Fe(CO) 4 } 3 ] ([Et 4 N] 2 [I]) has been explored with the goal of preparing heterometallic compounds for use as single-source precursors to metal pnictide phases. Reaction of AgPF 6 with [Et 4 N] 2 [I] in THF produces [Et 4 N][HAs{Fe 2 (CO) 6 (μ-CO)(μ-H)}{Fe-(CO) 4 }] in 12% yield, but the yield is improved to 71% if the reaction is carried out with added [Et 4 N][HFe(CO) 4 ]. The structure possesses rare As−H and {Fe 2 (CO) 6 (μ-CO)(μ-H)} fragments. The addition of [CPh 3 ][BF 4 ] to [Et 4 N] 2 [I] in THF gives [Et 4 N][Fe 3 (CO) 9 (μ-CO){μ 3 -AsFe(CO) 4 }] in 45% yield. This compound is also obtained as a minor product from oxidation of [Et 4 N] 2 [I] with 1 equiv of AgPF 6, AsCl 3, SbCl 3 , or BiCl 3 in THF. The cluster consists of an Fe 3 As tetrahedron with an isolated Fe(CO) 4 unit bound to the arsenic in a spikedtetrahedral arrangement. Refluxing [Et 4 N] 2 [I] with 1 equiv of AgPF 6 in THF produces [Et 4 N][(μ-H) 2 Fe 3 (CO) 9 ){μ 3 -AsFe(CO) 4 }]. This cluster is similar to [Et 4 N][Fe 3 (CO) 9 (μ-CO){μ 3 -AsFe(CO) 4 }] with the bridging CO being replaced by two bridging hydride ligands. Treatment of [Et 4 N] 2 [I] with 1 equiv of Mn(CO) 5 Br in THF gives the spirocyclic compound [Et 4 N][{FeMn(CO) 8 }(μ 4 -As){Fe 2 (CO) 6 (μ-CO)(μ-H)}] in 52% yield. Refluxing this cluster in the presence of triethylamine and an additional 1.8 equiv of Mn(CO) 5 Br gives [Et 4 N][Fe 3 (CO) 9 (μ-CO){μ 3 -AsMn(CO) 4 Br-cis}] in low yield. Alternatively, treating [Et 4 N][{FeMn(CO) 8 }(μ 4 -As){Fe 2 (CO) 6 (μ-CO)(μ-H)}] with triflic acid or an oxidant ([Ox] = Cu + , Ag + , Cu 2+ , CPh 3 + ) in dichloromethane produces the two neutral compounds (μ-H) 2 Fe 3 (CO) 9 {μ 3 -AsMn(CO) 5 } and {FeMn(CO) 8 }(μ 4 -As){Fe 2 (CO) 8 } in trace amounts and high yield, respectively. The former could be removed by treatment with base in nonpolar solvents. Neutral {FeMn(CO) 8 }(μ 4 -As){Fe 2 (CO) 8 } can then be isolated by filtration and evaporation in 74% yield. An improved synthesis of the known [Fe 3 (CO) 9 (μ-CO){μ 3 -PFe(CO) 4 }] − as its tetraethylammonium salt is also included. All compounds were characterized by spectroscopy, by ESI-mass spectrometry, and by single-crystal X-ray diffraction.

Periodical trends in [Co6E(CO)16]- clusters: Structural, synthetic and energy changes produced by substitution of P with As

“…Moreover, we plan to carry out thorough characterizations of the electron density distributions in both isomers. (11) 1172(4) 1487(4) 1366(4) 96(3) C (12) 1534(5) -279(6) 2783(6) 90(4) O (12) 1966(4) -357(6) 2466(5) 157(5) C (13) 841(5) -912(6) 3733(6) 78(4) O (13) 864(4) -1375(4) 4037 (5) 118(3) C (14) 1109 (5) 452 (6) 3807 (6) 76(4) O (14) 1271 (…”

“…[2] Accordingly, the quoted [Rh 10 As(CO) 22 ] 3was self-assembled in conditions suitable for the homogeneous catalytic conversion of CO-H 2 mixtures into oxygenated compounds, and proved to be stable at partial pressures of CO as high as 260 atm. [5] More recently, this class of compounds has been used as single source for the preparation of binary and ternary phases which, [12] on turn, can find application for magnetic nanoparticles, [13] for the deposition of thin films [14] or for electrocatalysis. [15] In the latter field, the presence of the main group element helps in forming amorphous layers which are more catalytically active than bulk metal.…”

Transition metal complexes of the naked pnictide elements

“…In the case of Ru5(CO)13(dppm)(Cl)(µ5-P) ( Figure 48A), the organic groups of Ru5(CO)13(dppm)(PN i Pr2) with HCl. The compound shows an irregular array of 5 Ru atoms attached to phosphorus giving rise to a 31 (Figure 48C and D).…”

The Parent Diarsene HAs=AsH as Side‐on Bound Ligand in an Iron Carbonyl Complex

“…[26] Moreover,i nt he literature,t here are only af ew complexes described containing AsH ligands in which the arsenic is tetrahedrally coordinated such as [{HOs 2 -(CO) 7 }AsH{HOs(CO) 4 }] or [Et 4 N][HAs{Fe 2 (CO) 6 (m-CO)(m-H)}{Fe(CO) 4 }]. [27] In summary,wewere able to isolate and characterize the very sensitive complex 2,c ontaining the unprecedented parent diarsene HAs = AsH as side-on coordinating ligand, which is stabilized in the coordination sphere of am ononuclear Fe(CO) 4 fragment without further stabilization by bulky organic substituents.A lthough 2 is highly sensitive and only stable at low temperatures,i tc ould be comprehensively characterized. DFT calculations show that 2 is best described as an olefin-like complex in which the As = As double bond character is preserved.…”