An m-phthalic diamide-linked bisporphyrin with a benzylamide substituent has been designed and synthesized. It has two types of carbonyl groups. In the solution of this zinc bisporphyrinate, these carbonyl groups are involved in the formation of two different Zn–O coordination interactions: one is formed between neighboring zinc bisporphyrinates; another is formed within zinc bisporphyrinate. The chirality sensing abilities of this zinc porphyrinate to a number of chiral monoamines have been examined. When zinc bisporphyrinate was mixed with a series of chiral monoamines, the signs of the circular dichroism spectra for the chiral monoamines of the same handedness with an aryl group as the substituent are just opposite to those with an alkyl group as the substituent. NMR studies reveal that stepwise coordinations lead to 1:1 and 1:2 host–guest complexes. The structure of the 1:1 host–guest complex was confirmed by crystallography, it is the first time that a 1:1 host–guest complex formed between zinc bisporphyrinate and a chiral monoamine has been crystallographically characterized. The structure reveals that there is an intramolecular hydrogen bond between the amide oxygen and the coordinated NH2. We further investigated the chirality transfer mechanism by density functional theory calculations. Our studies suggest that the interactions between the linker and guests in this bisporphyrin system are crucial in the chirality transfer process, and the nature of the bulkiest substituent of chiral monoamines makes a difference. For R-type guests, with an alkyl group, the steric repulsion makes the conformer A more energetically favorable, which leads to the anticlockwise twist and negative Cotton effect. However, with an aryl group, the π–π interaction makes the conformer B more energetically favorable, which leads to the clockwise twist and positive Cotton effect.

Reactions of PdCl2 with 2 equiv of N,N′-disubstituted-imidazole-2-thiones R1R2C3N2S (R1 = R2 = Me (1a), iPr (1b), Cy (1c), C6Me3H2 (1d); R1 = Me, R2 = Ph (1e)) under the different conditions afford five mononuclear complexes trans-[(R1R2C3N2S)2PdCl2] (R1 = R2 = Me (2a), iPr (2b), Cy (2c), C6Me3H2 (2d); R1 = Me, R2 = Ph (2e)) and five binuclear Pd(II) complexes [(PdCl2){μ-(R1R2C3N2S)}]2 (R1 = R2 = Me (3a), iPr (3b), Cy (3c), C6Me3H2 (3d); R1 = Me, R2 = Ph (3e)), respectively. Complexes 2a–2e are easily converted into the corresponding 3a–3e by adding equimolar PdCl2 in refluxing MeOH, while the reverse reaction is achieved at room temperature by addition of 2 equiv of 1a–1e. In 2b, 2d, and 2e, each Pd(II) holds a distorted square planar geometry completed by two trans Cl atoms and two trans S atoms. Complexes 3a–3e have a dimeric [Pd2S2] structure in which two {PdCl2} units are interlinked by two N,N′-disubstituted-imidazole-2-thiones. Each Pd(II) adopts a distorted square planar geometry accomplished by two cis Cl atoms and two cis bridging S atoms. Among them, complex 3d has the two largest C6Me3H2 groups on the 2 and 5 positions of imidazole-2-thione, the longest Pd−μ-S bond, the largest S–Pd–S angle, and displays the highest catalytic activity toward Suzuki–Miyaura and copper-free Sonogashira cross-coupling reactions, which are confirmed by density functional theory calculations. The results provide an interesting insight into the introduction of various substituent groups into the periphery ligands of coordination complex-based catalysts, which could tune their geometric structures to acquire the best catalytic activity toward organic reactions.

A mechanism study of quinine-squaramide catalyzed enantioselective aza-Friedel–Crafts (aza-F–C) reaction is described using density functional theory (DFT). The most favorable pathway is obtained through the discussions of four possible modes of hydrogen bond interactions, in which the nucleophile is activated by the squaramide N–H groups (N–Ha and N–Hb) and the electrophile binds to the protonated amine by hydrogen bonding. Meanwhile, we have also studied the energy barrier of the stereocontrolling transition states that might play a role of stereoselectivity. In addition, noncovalent interaction (NCI) analyses show a series of favorable cooperative noncovalent interactions, including N–H···O and C–H···F hydrogen-bonding, and π···π interactions. The strong interactions and lower barrier were found for TS3R, indicating the preference for the R-configuration adduct, which is in good agreement with the experimental observations.

We have designed and synthesized a novel zinc trisporphyrinate with a benzene tricarboxamide as the linker. In the presence of a large excess of 1-phenylethylamine, single crystals of the corresponding 1:3 host–guest complex were obtained, which provide the crystallographic structure of a host–guest complex consisting of an achiral porphyrin and a chiral monoamine. The structure reveals the 1-phenylethylamines adopt the “inside” binding mode that is stabilized by intramolecular hydrogen bonds. The NH2 of the 1-phenylethylamine is involved in both coordination and hydrogen bonding interactions. Circular dichroism (CD) and ultraviolet–visible spectra revealed that the 1:3 host–guest complex is dominant in the presence of a large excess of 1-phenylethylamine. The crystal structure shows there are two diastereomers of the 1:3 host–guest complexes. Density functional theory and TDDFT calculations suggest that one of the diastereomers is more energetically favorable, which dominates the CD signals.

A new host–guest system is formed between a benzene tricarboxamide linked zinc trisporphyrinate and a chiral monoalcohol (1-phenylethylalcohol). CD spectra show the chirality induction and inversion processes, which are controlled by the corresponding 1:1 and 1:2 coordination complexes. The binding constants calculated by UV-vis and CD spectral data are much larger than that for [Zn(TPP)] (TPP = tetraphenylporphyrin). The crystallographic structure of the host–guest complex reveals that multiple intramolecular hydrogen bonds and π–π interactions could contribute to its high binding affinity to 1-phenylethylalcohol. The DFT calculations suggest that the spatial orientations of porphyrin moieties change from the 1:1 complex to the 1:2 complex. The chirality induction and inversion processes are rationalized by the summation of pairwise interactions among multichromophores according to pairwise additivity.

The possible transition states of C–H activation on the dehydrogenate coupling of arenes with alcohols employing Ag(I) additives were investigated using B3LYP density functional theory. The AgOTf salt with Cu(OAc)2 was identified as the most active catalyst. The facile occurrence of the studied reactions is supported by the low activation energies of their respective transition states.

•Detailed ammonia borane dehydrogenation mechanism is investigated.•The ligand-assisted concerted FeCipso cooperation mechanism is most favorable.•FePOCOP pincer with a MeO group exhibits the highest catalytic activity.A quantum-chemical mechanistic investigation using density functional theory (DFT) on ammonia-borane dehydrogenation catalyzed by a series of iron bis(phosphinite) pincer complexes is reported. A metal-ligand cooperation mechanism has been proposed, in which the hydrogen atom of BH moves to metal Fe and proton of NH transfers to pincer ipso carbon simultaneously with the lowest activation barriers. DFT calculations and natural bond orbital (NBO) charge analysis suggest that FePOCOP complex with an electron-donating MeO group at the para position to the ipso carbon exhibits the highest catalytic activity. A plausible explanation of the observed catalytic activities is also given.

A formal thio [3 + 3]-cyclization catalyzed by a DPEN-derived chiral thiourea has been reported for the construction of optically active thiopyrano-indole annulated heterocyclic compounds in high yields with excellent enantioselectivities. The high reactivity between indoline-2-thione (keto-S) and 2-benzylidenemalononitrile has also been supported by density functional theory (DFT) calculations.

The regioselective and enantioselective Michael addition between azlactones and o-hydroxy chalcone derivatives is reported. Enantiomerically enriched N,O-aminals with two continuous stereogenic centers are exclusively obtained in moderate to good yields with excellent diastereoselectivities and good to excellent enantioselectivities. The experimental results show that an o-hydroxy group on the cinnamenyl motif of chalcone derivatives plays a crucial role at the reaction sites for the regioselective Michael addition. In addition, circular dichroism (CD) spectroscopy and density functional theory (DFT) are used to investigate the absolute configuration of N,O-aminals and the corresponding transition-state structures.

Computational studies have been performed to elucidate the activation mechanism of the Michael addition reactions containing bifunctional tertiary amine–thioureas and isatylidene malononitriles by density functional theory (DFT) calculations at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory. Results showed a difference of 6.47 kcal mol−1 between M1-O and M1-N, which suggest that it is the carbonyl group, instead of the malononitrile moiety of isatylidene malononitriles, that plays a dominating role in the activation of the electrophile by the catalysts. The predicted mechanism also successfully explains the experimentally observed enantioselectivity.

A theoretical understanding of the Pd-catalyzed C(sp3)–H activation of aliphatic amines has been examined using the B3LYP density functional theory. The concerted metalation–deprotonation (CMD) mechanism is identified in the rate-determining steps of all possible reaction pathways. The rate- and regio-determining step of the catalytic cycle is deprotonation of the Cmethyl–H bond through a six-membered cyclopalladation transition state. According to the relative activation barriers, the Cmethyl–H activation is kinetically and thermodynamically more favorable than the Cethyl–H activation. More important, the only acetoxylation product is located, ignoring the diethyl-substituted or the dimethyl-substituted in the morpholine and not producing the lactone amines molecules, which is in good agreement with the experimental observations.

The asymmetric Strecker-type reaction between azomethine imines and TMSCN was catalyzed by 1 mol% of a cinchona alkaloid-derived thiourea bearing multiple hydrogen-bonding donors to afford optically active amino nitriles in good to excellent yields and enantioselectivities.

A new host–guest system is formed between a benzene tricarboxamide linked zinc trisporphyrinate and a chiral monoalcohol (1-phenylethylalcohol). CD spectra show the chirality induction and inversion processes, which are controlled by the corresponding 1:1 and 1:2 coordination complexes. The binding constants calculated by UV-vis and CD spectral data are much larger than that for [Zn(TPP)] (TPP = tetraphenylporphyrin). The crystallographic structure of the host–guest complex reveals that multiple intramolecular hydrogen bonds and π–π interactions could contribute to its high binding affinity to 1-phenylethylalcohol. The DFT calculations suggest that the spatial orientations of porphyrin moieties change from the 1:1 complex to the 1:2 complex. The chirality induction and inversion processes are rationalized by the summation of pairwise interactions among multichromophores according to pairwise additivity.

The regioselective and enantioselective Michael addition between azlactones and o-hydroxy chalcone derivatives is reported. Enantiomerically enriched N,O-aminals with two continuous stereogenic centers are exclusively obtained in moderate to good yields with excellent diastereoselectivities and good to excellent enantioselectivities. The experimental results show that an o-hydroxy group on the cinnamenyl motif of chalcone derivatives plays a crucial role at the reaction sites for the regioselective Michael addition. In addition, circular dichroism (CD) spectroscopy and density functional theory (DFT) are used to investigate the absolute configuration of N,O-aminals and the corresponding transition-state structures.