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The tetrel-bonded complexes formed between the selected boron-substituted carbenes and TH3F (T = C, Si, Ge, Sn, Pb) have been explored by using the high-level quantum chemical method. The binding sites of TH3F in the complexes are generally consistent with the positions of VS,min points of the carbenes, and the -Eint values of the complexes exhibit a general increasing tendency with the increase of the -VS,min values of the carbenes for a given TH3F. The complexes can be divided into the type-I and type-II groups. The type-I complexes are characterized by the 3c(B-C-B)→BD*(T-F) and BD(B-C)→BD*(T-F) orbital interactions, and the type-II complexes are characterized by the LP(C)→BD*(T-F) orbital interactions. The type-II complexes have more negative Eint values than the type-I complexes. The -Eint values of the type-I complexes exhibit a roughly increasing tendency with the increase of the T atomic number, and the -Eint values go in the order SnH3F > PbH3F > GeH3F > SiH3F > CH3F for most type-I complexes, which is consistent with the order of VS,max values of TH3F. Unlike type-I complexes, the -Eint values of the type-II complexes exhibit a zigzag tendency with the increase of the T atomic number, and the -Eint values go in the order SiH3F > SnH3F > GeH3F > PbH3F > CH3F for type-II complexes. The AIM and SAPT analysis has been employed to explore the nature of the intermolecular interactions in these complexes. [ABSTRACT FROM AUTHOR]

Methods: The intermolecular interactions between the heavy-atom analogues of acetylene T2H2 (T = Si, Ge, Sn, Pb) and HCN have been investigated by theoretical calculations at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ level. Results: The global energy minimum of T2H2 is the butterfly structure A, and another energy minimum is the planar structure B. Both structures A and B exhibit the dual behavior when binding with HCN. The various hydrogen bond (HB), dihydrogen bond (DB) and tetrel bond (TB) complexes can be found according to the MEP maps of T2H2. One TB and three HB complexes formed between structure A and HCN can be located for Si2H2 and Ge2H2. One TB, two HB and one DB complexes formed between structure A and HCN can be located for Sn2H2 and Pb2H2. Four TB and one HB complexes formed between structure B and HCN can be located for all the T2H2. The geometries and binding strengths of the complexes are compared and analyzed. Conclusions: The interactions in these complexes are generally weak, and the interaction energies of these complexes range from −0.53 to −8.23 kcal/mol. The interaction energies of the TB complexes are larger than those of the corresponding HB and DB complexes for structure A···HCN systems. The relative binding strength of the four TB complexes exhibits different order for different structure B···HCN systems, which is consistent with the MEP maps of the isolated monomers. [ABSTRACT FROM AUTHOR]

The intermolecular interactions between the heavy alkenes H2Si = TH2 (T = C, Si, Ge, Sn, Pb) and C2H2 have been calculated at the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVDZ level, and the nature of these complexes has been investigated by natural bond orbital. The four types (type-A, type-B, type-C and type-D) of complexes can be located for H2Si = TH2···C2H2 system. The complexes involving H2Si = TH2···C2F2 and H2Si = TH2···C2(CN)2 have also been examined to explore the substituent effects. Some complexes which are stable for H2Si = TH2···C2H2 system become unstable for H2Si = TH2···C2F2 or H2Si = TH2···C2(CN)2 system, while other complexes which are unstable for H2Si = TH2···C2H2 system become stable for H2Si = TH2···C2F2 or H2Si = TH2···C2(CN)2 system. [ABSTRACT FROM AUTHOR]

The binary and ternary complexes composed of GeH3F, AsH2F and ring compounds (benzene, borazine and cyclopentadienyl anion) have been studied by theoretical calculations to understand the interplay between the tetrel bond and pnicogen bond interactions. The bonding strength of intermolecular interactions in these complexes is analyzed by means of atoms in molecules (AIM), natural bond orbital (NBO) and noncovalent interaction (NCI) index methods. The binary tetrel-bonded and pnicogen-bonded complexes can be classified as an n-type or π-type complex according to the orbital interactions involved in the complexes. Three binding modes can be distinguished according to the interplay between interactions for the ternary complexes. The binding mode A is characterized by the interplay between π-type tetrel bond and n-type pnicogen bond; binding mode B is characterized by the interplay between π-type pnicogen bond and n-type tetrel bond, and binding mode C is characterized by the interplay between π-type tetrel bond and π-type pnicogen bond. The binding modes A and B exhibit the synergistic interplay effect, while the antagonistic effect is reflected in mode C. The synergistic effect in binding modes A and B is stronger than antagonistic effect in mode C, and the synergistic effect in binding mode B is stronger than that in mode A. [ABSTRACT FROM AUTHOR]

The ternary complexes X · 1 · YF ( 1 = triazine, X = Cl, Br and I, Y = H, Cl, Br, I, PH and AsH) have been investigated by MP2 calculations to understand the noncovalently electron-withdrawing effects on anion-arene interactions. The results indicate that in binary complexes ( 1 · X), both weak σ-type and anion-π complexes can be formed for Cl and Br, but only anion-π complex can be formed for I. Moreover, the hydrogen-bonding complex is the global minimum for all three halides in binary complexes. However, in ternary complexes, anion-π complex become unstable and only σ complex can retain in many cases for Cl and Br. Anion-π complex keeps stable only when YF = HF. In contrast with binary complexes, σ complex become the global minimum for Cl and Br in ternary complexes. These changes in binding mode and strength are consistent with the results of covalently electron-withdrawing effects. However, in contrast with the covalently electron-withdrawing substituents, Cl and Br can attack the aromatic carbon atom to form a strong σ complex when the noncovalently electron-withdrawing effect is induced by halogen bonding. The binding behavior for I is different from that for Cl and Br in two aspects. First, the anion-π complex for I can also keep stable when the noncovalent interaction is halogen bonding. Second, the anion-π complex for I is the global minimum when it can retain as a stable structure. [ABSTRACT FROM AUTHOR]

A new zirconia-based stationary phase (DPZ) was prepared by modifying zirconia with dodecylamine- N, N-dimethylenephosphonic acid (DDPA). DDPA was adsorbed on zirconia with only one phosphonic group, with the other being free. Besides the hydrophobic interaction provided by nonpolar dodecyl, DPZ also has dipolar interaction, ion-exchange or electrostatic repellent interaction provided by the free phosphonic group and amino group at different conditions. Separation of bases on this stationary phase was achieved with satisfaction owing to the various retention mechanisms. The influence of methanol content, pH value, ion types, and ionic strength of mobile phase are studied in detail. [ABSTRACT FROM AUTHOR]