Syntheses, Structures, and Characterization of Nickel(II) Stibines: Steric and Electronic Rationale for Metal Deposition

Abstract

Reactions of the homoleptic and heteroleptic antimony ligands Sb Pr, Sb PrPh, SbMePh, and SbMePh with NiI generate rare Ni stibine complexes in either square planar or trigonal bipyramidal (TBP) geometries, depending on the steric size of the ligands. Tolman electronic parameters were calculated (DFT) for each antimony ligand to provide a tabulated resource for the relative strengths of simple antimony ligands. The electronic absorbance spectra of the square planar complexes exhibit characteristic bands [λ ≈ 560 nm (17 900 cm), ε ≈ 4330 M cm] at lower energies compared to the reported phosphine complexes, indicating the weak donor strength of the stibine ligands and resultant low-energy ligand field d→ d transitions. The square planar complex Ni(I)(Sb Pr) reacts with CO to form the TBP complex Ni(I)(Sb Pr)(CO). Lastly, the complexes were investigated for nickel metal deposition on Si|Cu(100 nm) substrates. The complexes with the strongest donating ligand, Sb Pr, deposited the purest layer of NiCu alloy according to the balanced reaction Ni(I)(SbPr) → Ni + Sb( Pr)I; the iodinated Sb byproduct was unambiguously detected in the supernatant by H NMR and mass spectrometry. Complexes with weaker ligands (poor I acceptors/scavengers) resulted undesired deposition of iodine and CuI on the surface. This work thus serves as a guide for the design and synthesis of 3 d metal complexes with neutral, heavy main-group donors that are useful for metal deposition applications.

Thermoluminescent Antimony-Supported Copper-Iodo Cuboids: Approaching NIR Emission via High Crystallographic Symmetry

“…We previously reported that several of the ligands used herein (SbMe 2 Ph, Sb i Pr 2 Ph, and Sb i Pr 3 ) bind and structurally stabilize nickel­(II) . In addition, several ligands employed in this work were previously synthesized by others (SbCy 3 , Sb t Bu 3 , Sb t Bu 2 Ph) , or can be purchased commercially (SbPh 3 ).…”

“…In addition, several ligands employed in this work were previously synthesized by others (SbCy 3 , Sb t Bu 3 , Sb t Bu 2 Ph) , or can be purchased commercially (SbPh 3 ). While several of these ligands have been used in metalations with other 3d transition metalsboth in our work and othersonly SbPh 3 has been used specifically in copper metalations; such studies only obtained monomeric and dimeric structures of CuX (X = Cl, Br, I), ,− rather than the cuboid type structures of interest in this work. Thus, overall, with the stated exception of SbPh 3 , none of the copper-binding parameters or structural motifs derived from homoleptic and heteroleptic SbR 3 ligands have been reported.…”

“…We previously reported that several of the ligands used herein (SbMe 2 Ph, Sb i Pr 2 Ph, and Sb i Pr 3 ) bind and structurally stabilize nickel(II). 38 In addition, several ligands employed in this work were previously synthesized by others (SbCy 3 , Sb t Bu 3 , Sb t Bu 2 Ph) 39,40 or can be purchased commercially (SbPh 3 ). While several of these ligands have been used in metalations with other 3d transition metalsboth in our work and othersonly SbPh 3 has been used specifically in copper metalations; such studies only obtained monomeric and dimeric structures of CuX (X = Cl, Br, I), 38,41−44 rather than the cuboid type structures of interest in this work.…”

“…Using the classical Tolman electronic parameter (TEP) to define the electronic strength of our antimony ligands, we have shown previously that the addition of a single phenyl group does lower the TEP versus an all-alkyl analogue, while higher aliphatic organic substituents increased the TEP (i.e., isopropyl versus methyl). 38 Although it is difficult to quantify the TEP for the bulkier ligands (e.g., Sb t Bu3, SbCy 3 ), we can extract useful information by examining analogous phosphine compounds (P t Bu 3TEP = 2056 cm −1 ; PCy 3TEP = 2056 cm −1 ). 75 Thus, an approximate order of Sb-ligand strength would follow as Sb t Bu 3 = SbCy 3 > Sb t Bu 2 Ph > Sb i Pr 3 > Sb i Pr 2 Ph.…”

Isolation and X-ray Structure of a Dialkylbismuth(III) Iodo “Nanosquare”: Breaking the Polymeric Mold of R2BiX

“…Recently, we have made advances in ligating soft, heavy main-group ligands to hard first-row metals. In particular, our studies of antimony complexes of nickel, copper, and cobalt motivate the extension of similar methodologies to bismuth. Historically, bismuth has not served as a good donor in transition-metal systems because of its contracted 6s orbital, i.e., an “inert lone pair”. ,− As a result, more purely 6p bonding motifs generally dominate bismuth structures.…”