Simulations Suggest Possible Triply Bonded Phosphorus≡E13 Molecules (E13 = B, Al, Ga, In, and Tl)

The effect of substitution on the potential energy surfaces of RE13 ☰ PR (E13 = B, Al, Ga, In, Tl; R = F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt, and Ar* is studied using density functional theory (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP and B3LYP/LANL2DZ + dp). The theoretical results demonstrate that all triply bonded RE13 ☰ PR compounds with small substituents are unstable and spontaneously rearrange to other doubly bonded isomers. That is, the smaller groups, such as R 〓 F, OH, H, CH3 and SiH3, neither kinetically nor thermodynamically stabilize the triply bonded RE13 ☰ PR compounds. However, the triply bonded R’E13☰PR´ molecules, possessing bulkier substituents (R´ = SiMe(SitBu3)2, SiiPrDis2, Tbt and Ar*), are found to have a global minimum on the singlet potential energy surface. In particular, the bonding character of the R’E13☰PR´ species is well defined by the valence-electron bonding model (model [II]). That is to say, R’E13☰PR´ molecules that feature groups are regarded as R′-E13P-R′. The theoretical evidence shows that both the electronic and the steric effects of bulkier substituent groups play a prominent role in rendering triply bonded R′E13☰PR′ species synthetically accessible and isolable in a stable form

The Triply Bonded Al☰Sb Molecules: A Theoretical Prediction

The effect of substitution on the potential energy surfaces of RAl☰SbR (R = F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt, and Ar*) is investigated using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ + dp). The theoretical results demonstrated that all the triply bonded RAl☰SbR compounds with small substituents are unstable and can spontaneously rearrange to other doubly bonded isomers. That is, the smaller groups, such as R = F, OH, H, CH3 and SiH3, neither kinetically nor thermodynamically stabilize the triply bonded RAl☰SbR compounds. However, the triply bonded R’Al☰SbR´ molecules that feature bulkier substituents (R´ = SiMe(SitBu3)2, SiiPrDis2, Tbt, and Ar*) are found to possess the global minimum on the singlet potential energy surface and are both kinetically and thermodynamically stable. In particular, the bonding characters of the R’Al☰SbR´ species agree well with the valence-electron bonding model (model) as well as several theoretical analyses (the natural bond orbital, the natural resonance theory, and the charge decomposition analysis). That is to say, R’Al☰SbR´ molecules that feature groups are regarded as R′─Al Sb─R′. Their theoretical evidence shows that both the electronic and the steric effects of bulkier substituent groups play a decisive role in making triply bonded R′Al☰SbR′ species synthetically accessible and isolable in a stable form

The Mechanisms for the Oxidative Addition of Imidazolium Salts to a Group 9 Transition Metal Atom (Co0, Rh0, and Ir0) and a Group 10 Transition Metal Atom (Ni0, Pd0, and Pt0): A Theoretical Study

The potential energy surfaces of the oxidative addition reactions, L2M + imidazoliumcation → product and CpM′L + imidazolium cation → product (M = Ni, Pd, Pt; M′ = Co, Rh, Ir; Cp = η5-C5H5; L = 1,3-aryl-N-heterocyclic carbene (NHC), aryl = 2,4,6-trimethylphenyl), are studied at the M06-L/Def2-SVP level of theory. The theoretical findings show that the singlet-triplet splitting (∆Est = Etriplet − Esinglet) for the L2M and CpM′L species can be used to predict the reactivity for their oxidative additions. That is to say, current theoretical evidence suggests that both a 14-electron L2M complex and a 16-electron CpM′Lcomplex with a better electron-donating ligand L (such as NHC) result in a reduced ∆Est value and facilitate the oxidative addition to the saturated C─H bond. The theoretical results for this study are in good agreement with the obtainable experimental results and allow a number of predictions to be made

The Effect of Substituent on Molecules That Contain a Triple Bond Between Arsenic and Group 13 Elements: Theoretical Designs and Characterizations

The effect of substitution on the potential energy surfaces of RE13≡AsR (E13 = group 13 elements; R = F, OH, H, CH3, and SiH3) is determined using density functional theory (M06‐2X/Def2‐TZVP, B3PW91/Def2‐TZVP, and B3LYP/LANL2DZ+dp). The computational studies demonstrate that all triply bonded RE13≡AsR species prefer to adopt a bent geometry that is consistent with the valence electron model. The theoretical studies also demonstrate that RE13≡AsR molecules with smaller substituents are kinetically unstable, with respect to the intramolecular rearrangements. However, triply bonded R′E13≡AsR′ species with bulkier substituents (R′ = SiMe(SitBu3)2, SiiPrDis2, and NHC) are found to occupy the lowest minimum on the singlet potential energy surface, and they are both kinetically and thermodynamically stable. That is to say, the electronic and steric effects of bulky substituents play an important role in making molecules that feature an E13≡As triple bond as viable synthetic target

Triple Bonds between Bismuth and Group 13 Elements: Theoretical Designs and Characterization

The effect of substitution on the potential energy surfaces of RE13≡BiR (E13 = B, Al, Ga, In, and Tl; R = F, OH, H, CH3, SiH3, Tbt, Ar*, SiMe(SitBu3)2, and SiiPrDis2) is investigated using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The theoretical results suggest that all of the triply bonded RE13≡BiR molecules prefer to adopt a bent geometry (i.e., ∠RE13Bi ≈ 180° and ∠E13BiR ≈ 90°), which agrees well with the bonding model (model (B)). It is also demonstrated that the smaller groups, such as R = F, OH, H, CH3, and SiH3, neither kinetically nor thermodynamically stabilize the triply bonded RE13≡BiR compounds, except for the case of H3SiB≡BiSiH3. Nevertheless, the triply bonded RʹE13≡BiRʹ molecules that feature bulkier substituents (Rʹ = Tbt, Ar*, SiMe(SitBu3)2, and SiiPrDis2) are found to have the global minimum on the singlet potential energy surface and are both kinetically and thermodynamically stable. In other words, both the electronic and the steric effects of bulkier substituent groups play an important role in making triply bonded RE13≡BiR (Group 13–Group 15) species synthetically accessible and isolable in a stable form

Substituent Effects on the Stability of Thallium and Phosphorus Triple Bonds: A Density Functional Study

Three computational methods (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP and B3LYP/LANL2DZ+dp) were used to study the effect of substitution on the potential energy surfaces of RTl≡PR (R = F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt (=C6H2-2,4,6-(CH(SiMe3)2)3), and Ar* (=C6H3-2,6-(C6H2-2, 4,6-i-Pr3)2)). The theoretical results show that these triply bonded RTl≡PR compounds have a preference for a bent geometry (i.e., ∠R⎼Tl⎼P ≈ 180° and ∠Tl⎼P⎼R ≈ 120°). Two valence bond models are used to interpret the bonding character of the Tl≡P triple bond. One is model [I], which is best described as TlP. This interprets the bonding conditions for RTl≡PR molecules that feature small ligands. The other is model [II], which is best represented as TlP. This explains the bonding character of RTl≡PR molecules that feature large substituents. Irrespective of the types of substituents used for the RTl≡PR species, the theoretical investigations (based on the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) demonstrate that their Tl≡P triple bonds are very weak. However, the theoretical results predict that only bulkier substituents greatly stabilize the triply bonded RTl≡PR species, from the kinetic viewpoint

Indium–Arsenic Molecules with an InAs Triple Bond: A Theoretical Approach

The effect of substitution on the potential energy surfaces of RInAsR (R = F, OH, H, CH₃, and SiH₃ and R′ = SiMe­(Si<i>t</i>Bu₃)₂, Si<i>i</i>PrDis₂, and <i>N</i>-heterocyclic carbene (NHC)) is determined using density functional theory calculations (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The computational studies demonstrate that all of the triply bonded RInAsR species prefer to adopt a bent geometry, which is consistent with the valence electron model. The theoretical studies show that RInAsR molecules that have smaller substituents are kinetically unstable with respect to their intramolecular rearrangements. However, triply bonded R′InAsR′ species that have bulkier substituents (R′ = SiMe­(Si<i>t</i>Bu₃)₂, Si<i>i</i>PrDis₂, and NHC) occupy minima on the singlet potential energy surface, and they are both kinetically and thermodynamically stable. That is, the electronic and steric effects of bulky substituents play an important role in making molecules that feature an InAs triple bond viable as a synthetic target. Moreover, two valence bond models are used to interpret the bonding character of the InAs triple bond. One is model [A], which is best represented as . This interprets the bonding conditions for RInAsR molecules that feature small ligands. The other is model [B], which is best represented as . This explains the bonding character of RInPAsR molecules that feature large substituents

Triply Bonded GalliumPhosphorus Molecules: Theoretical Designs and Characterization

The effect of substitution on the potential energy surfaces of triple-bonded RGaPR (R = F, OH, H, CH₃, SiH₃, SiMe­(Si<i>t</i>Bu₃)₂, Si<i>i</i>PrDis₂, Tbt (C₆H₂-2,4,6-{CH­(SiMe₃)₂}₃), and Ar* (C₆H₃-2,6-(C₆H₂-2,4,6-<i>i</i>-Pr₃)₂)) compounds was theoretically examined by using density functional theory (i.e., M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). The theoretical evidence strongly suggests that all of the triple-bonded RGaPR species prefer to select a bent form with an angle (∠Ga–P–R) of about 90°. Moreover, the theoretical observations indicate that only the bulkier substituents, in particular, for the strong donating groups (e.g., SiMe­(Si<i>t</i>Bu₃)₂ and Si<i>i</i>PrDis₂) can efficiently stabilize the GaP triple bond. In addition, the bonding analyses (based on the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) reveal that the bonding characters of such triple-bonded RGaPR molecules should be regarded as R′Ga←PR′. In other words, the GaP triple bond involves one traditional σ bond, one traditional π bond, and one donor–acceptor π bond. Accordingly, the theoretical conclusions strongly suggest that the GaP triple bond in such acetylene analogues (RGaPR) should be very weak

Triple-Bonded BoronPhosphorus Molecule: Is That Possible?

The effect of substitution on the potential energy surfaces of RBPR (R = H, F, OH, SiH₃, and CH₃) is studied using density functional theories (M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, and B3LYP/LANL2DZ+dp). There is significant theoretical evidence that RBPR compounds with smaller substituents are fleeting intermediates, so they would be difficult to be detected experimentally. These theoretical studies using the M06-2X/Def2-TZVP method demonstrate that only the triply bonded R′BPR′ molecules bearing sterically bulky groups (R′ = Tbt (=C₆H₂-2,4,6-{CH­(SiMe₃)₂}₃), SiMe­(Si<i>t</i>Bu₃)₂, Ar* (=C₆H₃-2,6-(C₆H₂-2,4,6-<i>i</i>-Pr₃)₂), and Si<i>i</i>PrDis₂) are significantly stabilized and can be isolated experimentally. Using the simple valence-electron bonding model and some sophisticated theories, the bonding character of R′BPR′ should be viewed as R′BI PR′. The present theoretical observations indicate that both the electronic and the steric effect of bulkier substituent ligands play a key role in making triply bonded R′BPR′ species synthetically accessible and isolable in a stable form