Lone Pair Orbitals Research Articles

Spectroscopic and Quantum Chemical Investigation of Benzene-1,2-dithiolate-Coordinated Diiron Complexes with Relevance to Dinitrogen Activation.

In this work, a benzene-1,2-dithiolate (bdt) pentamethylcyclopentadienyl di-iron complex [Cp*Fe(μ-η2:η4-bdt)FeCp*] and its [Cp*Fe(bdt)(X)FeCp*] analogues (where X = N2H2, N2H3-, H-, NH2-, NHCH3-, or NO+) were investigated through spectroscopic and computational studies. These complexes are of relevance as model systems for dinitrogen activation in nitrogenase and share with its active site the presence of iron, sulfur ligands, and a very flexible electronic structure. On the basis of a combination of X-ray emission spectroscopy (XES), X-ray crystallography, Mössbauer, NMR, and EPR spectroscopy, the geometric and electronic structure of the series has been experimentally elucidated. All iron atoms were found to be in a local low-spin configuration. When no additional X ligand is bound, the bdt ligand is tilted and features a stabilizing π-interaction with one of the iron atoms. The number of lone-pair orbitals provided by the nitrogen-containing species is crucial to the overall electronic structure. When only one lone-pair is present and the iron atoms are bridged by one atom, a three-center bond occurs, and a direct Fe-Fe bond is absent. If the bridging atom provides two lone-pairs, then an Fe-Fe bond is formed. A recurring theme for all ligands is σ-donation into the unoccupied eg manifolds of both iron atoms and back-donation from the t2g manifolds into the ligand π* orbitals. The latter results in a weakening of the double bond of the bound ligand, and in the case of NO+, it results in a weakening of all bonds that comprise triple bond. The electron-rich thiolates further amplify this effect and can also serve as bases for proton binding. While the above observations have been made for the studied di-iron complexes, they may be of relevance for the active site in nitrogenase, where a similar N2 binding mode may occur allowing for the simultaneous weakening of the N2 σ bond and π bonds.

KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY

The isomerization reactions of the 4-amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione have been studied theoretically using density functional theory (DFT) along with various exchange-correlation functionals (B3LYP and M06-2x) as well as the benchmark CBS-QB3 quantum chemical approach. The calculated energy profile has been supplemented with calculations of kinetic rate constants by means of transition state theory (TST).Based on the optimized isomers geometries using the CBS-QB3 method, a natural bond orbital analysis reveals that the electronic delocalization from non-bonding lone-pair orbitals [LP(e)S7] to the neighboring σ* N2-C3 antibonding orbital increase from isomer 1 to isomer 2. Also, the LP(e)S7→σ* N2-C3 delocalizations could fairly explain the increase of occupancies of LP(e) non-bonding orbitals in the ring of isomers 1 and 2 (2 > 1). The electronic delocalization from LP(e)S7 non-bonding to σ* N2-C3 antibonding orbitals increase the ground state structure stability, Therefore, the increase of LP(e)S7→σ*N2-C3 delocalizations could fairly explain the kinetics of the isomerization reactions 1 and 2 (k2 > k1). NBO results also suggest that the kinetics of these processes are controlled by LP→σ* resonance energies.

A Multireference Ab Initio Study of the Diradical Isomers of Pyrazine.

Three diradical pyrazine isomers were characterized using highly correlated, multireference methods. The lowest lying singlet and triplet state geometries of 2,3-didehydropyrazine ( ortho), 2,5-didehydropyrazine ( para), and 2,6-didehydropyrazine ( meta) were determined. Two active reference spaces were utilized. The complete active space (CAS) (8,8) includes the σ and σ* orbitals on the dehydrocarbon atoms as well as the valence π and π* orbitals. The CAS (12,10) reference space includes two additional orbitals corresponding to the in-phase and out-of-phase nitrogen lone pair orbitals. Adiabatic and vertical gaps between the lowest lying singlet and triplet states, optimized geometries, canonicalized orbital energies, unpaired electron densities, and spin polarization effects were compared. We find that the singlet states of each diradical isomer contain two significantly weighted configurations, and the larger active space is necessary for the proper physical characterization of both the singlet and triplet states. The singlet-triplet splitting is very small for the 2,3-didehydropyrazine ( ortho) and 2,6-didehydropyrazine ( meta) isomers (+1.8 and -1.4 kcal/mol, respectively) and significant for the 2,5-didehydropyrazine ( para) isomer (+28.2 kcal/mol). Singlet geometries show through-space interactions between the dehydocarbon atoms in the 2,3-didehydropyrazine ( ortho) and 2,6-didehydropyrazine ( meta) isomers. An analysis of the effectively unpaired electrons suggests that the 2,5-didehydropyrazine ( para) isomer also displays through-bond coupling between the diradical electrons.

Phosphines featuring a hexafluorocyclopentene skeleton: Synthesis, coordination properties, and applications for Lewis-acidic transition-metal catalysts

Weakly σ-donating phosphines bearing a hexafluorocyclopentene skeleton were synthesized. The 1JPSe coupling constants of selenides of the fluorinated phosphines revealed substantially decreased s-character of the phosphorus lone pair orbitals of the fluorinated phosphines, indicating their weak σ-donating ability. Au(I), Pd(II) and Pt(II) complexes bearing the fluorinated phosphines showed moderate catalytic activity in the hydration and hydroarylation of alkynes.

Halide exchange studies of novel Pd(ii) NNN-pincer complexes.

Palladium(ii) complexes with an NNN type pincer ligand (pip2NNN = 2,6-bis(piperdyl-methyl)pyridine) are synthesized and characterized. Electronic and 1H NMR spectra point to decreasing filled/filled repulsions between the dπ(Pd) orbitals and the halide lone pair orbitals along the Cl < Br < I series. For all complexes, the most downfield α-piperidyl resonance of the pip2NNN ligand is sensitive to changes in the coordinated halide while the meta-pyridyl and benzylic resonances are sensitive to changes in the counter anion. This sensitivity is utilized to study halide association and exchange at the fourth coordination site. Conductivity and 1H NMR spectroscopy confirm the interaction between the exogenous anion (Cl−, Br−, BF4−) and Pd(pip2NNN)X+ (X = Cl, Br).

Understanding the isomerization kinetics in the gas phase of a triazole-3-thione derivative: A theoretical approach

The isomerization reactions of the 4-amino-5-methyl-2,4-dihydro- -3H-1,2,4-triazole-3-thione were studied using the B3LYP and M06-2x, as well as the CBS-QB3 theoretical methods. The measured energy profiles were complemented with kinetic rate constants using the transition state theory (TST). Based on the isomers geometries optimized using the CBS-QB3 method, a natural bond orbital (NBO) analysis shows that the stabilization energies of non-bonding lone-pair orbitals [LP(e)S7] to the ?*N2?C3 antibonding orbital increase from isomers 1 to 2. Moreover, the LP(e)S7 ? ?*N2?C3 delocalizations could fairly explain the increase in the occupancies of LP(e)S7 orbitals for isomers 1 and 2 (2 &gt; 1). The studied stabilization energy increases the stability of the ground state structure, and could fairly explain the kinetics of the isomerization reactions 1 and 2 (k2 &gt; k1). NBO results also suggest that the kinetics of these processes are controlled by the LP ??* resonance energies.

Ibuprofen-thiadiazole hybrid compounds: Synthesis, vibrational analysis and molecular structure of 5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine hydrochloride

The ibuprofen derivative 5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine hydrochloride is prepared by via cyclization of ibuprofen with thiosemicarbazide in the presence of POCl3. The compound has been characterized by using FT-IR and multinuclear (1H and 13C) NMR spectroscopies, and elemental analysis. The molecular structure in crystalline phase has been determined by single crystal X-Ray diffraction. The compound crystallizes in the triclinic system with space group P-1 as discrete cations and chloride anions with two enantiomers present in the asymmetric unit. A full vibrational analysis of the FT-IR and FT-Raman spectra has been performed in conjunction with quantum chemical calculations. Experimental data agree with the occurrence of the thiadiazole NH protonated form in the solid phase. The observation of the ν(NN) and δ(CNN) normal modes as strong signals in the infrared and Raman spectra at 1189 (1180 cm−1) and 774 cm−1 suggests a NN bond with partial double bond character in the thiadiazole moiety, in good agreement with the computed values at the B3LYP/6-311++G(d,p) level of approximation. The NBO analysis showed that both, the sulfur lone pair and the exocyclic amine nitrogen lone pair orbitals contribute to strong resonance interactions with the adjacent π*(N2=C8) antibonding orbital of the protonated thiadiazole group.

Theoretical Insights into Vinyl Derivatives Adsorption on a Cu(100) Surface

Here, we present a thorough theoretical study of the adsorption of acrolein (ACO), acrylonitrile (ACN), and acrylamide (ACA) on Cu(100) surface. For this purpose, we have used the density functional theory, imposing periodic boundary conditions to have a correct description of the electronic band structure of the metal and including dispersion forces through two different schemes: the D2 method of Grimme and the vdW-DF. We have found several adsorption geometries. In all of them, the vinyl group together with the amide (in ACA), ciano (in ACN), and carbonyl (in ACO) groups, is highly involved. The highest adsorption energy is found for acrylamide, followed by acrolein and the lowest for acrylonitrile (depending on the level of theory employed ∼1.2, 1.0, and 0.9 eV, respectively). We show that a strong coupling between the π electronic system (both occupied and virtual orbitals) and the electronic levels of the metal is mainly responsible of the chemisorption. As a consequence, electronic density is transferred from the surface to the molecule, whose carbon atoms acquire a partial sp3 hybridization. Lone-pair orbitals of the cyano, amide, and carbonyl groups also play a role in the interaction. The simulations and following analysis allow to disentangle the nature of the interaction, which can be explained on the basis of a simple chemical picture: donation from the occupied lone pair and π orbitals of the molecule to the surface and backdonation from the surface to the π* orbital of the molecule (π-backbonding).

Quantitative Assessment of Tetrel Bonding Utilizing Vibrational Spectroscopy.

A set of 35 representative neutral and charged tetrel complexes was investigated with the objective of finding the factors that influence the strength of tetrel bonding involving single bonded C, Si, and Ge donors and double bonded C or Si donors. For the first time, we introduced an intrinsic bond strength measure for tetrel bonding, derived from calculated vibrational spectroscopy data obtained at the CCSD(T)/aug-cc-pVTZ level of theory and used this measure to rationalize and order the tetrel bonds. Our study revealed that the strength of tetrel bonds is affected by several factors, such as the magnitude of the σ-hole in the tetrel atom, the negative electrostatic potential at the lone pair of the tetrel-acceptor, the positive charge at the peripheral hydrogen of the tetrel-donor, the exchange-repulsion between the lone pair orbitals of the peripheral atoms of the tetrel-donor and the heteroatom of the tetrel-acceptor, and the stabilization brought about by electron delocalization. Thus, focusing on just one or two of these factors, in particular, the σ-hole description can only lead to an incomplete picture. Tetrel bonding covers a range of −1.4 to −26 kcal/mol, which can be strengthened by substituting the peripheral ligands with electron-withdrawing substituents and by positively charged tetrel-donors or negatively charged tetrel-acceptors.

Where and How Does an Organic Molecule Having a C–X Bond Release X– Anion Like an Inorganic Compound? A Theoretical Study

In this research, at first, a comparative DFT study on hydride or fluoride release from a number of known orthoamides, their fluorine derivative having a central C-F bond and some simple organic compounds, is reported. The obtained data show that orthoamides release hydride or fluoride anions much easier than do other known organic compounds studied here. Interestingly, three simulated orthoamides having a central C-F bond, spontaneously and like an inorganic compound, release fluoride anion upon dissolving in polar solvents. The calculations confirmed that hyperconjugation interactions in the initial orthoamides facilitate the anion release from these compounds. However, the data clearly show that the proper overlap of an empty p orbital of the central carbon atom with adjacent lone-pair orbitals of nitrogen atoms ( lpN → lp*C or, in other words, the pπ-pπ interaction) in the resulting carbocations is a more important factor that must be taken into consideration when designing the hydride, fluoride, or other anion releasing agents. In addition, for the first time, a mechanism of hydride and fluoride removal from the orthoamides either through their reaction with BH3 and BF3 molecules, respectively, or upon their protonation is provided. To continue and for generalization of results to other groups attached to the central carbon atom of orthoamides, the reactions of H+ with orthoamides having the CH3, OH, CN, NH2, or C5H5 substituents were studied. The results showed that in all cases and in both gas and solution phases the above substituents easily leave the carbon atom as an anion and bond to H+. Thus, we have to conclude that upon the reaction of orthoamides with usual Lewis acids, many types of substituents on their central carbon atom can leave these compounds as anions.

Structural reactivity analyses of a neoflavonoid 4-methoxydalbergione using vibrational spectroscopy and quantum chemical calculations

In the present study, a combined theoretical and experimental approach is used to study the structure and properties of 4-methoxydalbergione (MD). The optimized geometry was calculated by B3LYP method using 6–311++G(d,p) basis set. Three conformers of MD (MD I, MD II and MD III) have been found by potential energy surface scan. The FT-Raman and FT-IR spectra were recorded in the solid phase, and interpreted in terms of potential energy distribution analysis. Good consistency is found between the calculated results and observed spectra. The detailed interpretation of electron delocalization from filled lone pair orbitals to unfilled antibonding molecular orbitals of most interacting molecular orbitals of the molecule has been done by natural bond orbital (NBO) analysis. HOMO-LUMO energy gap shows that chemical reactivity of MD II is higher than MD I and MD III. Molecular electrostatic potential (MEP) surface has also been predicted with the help of density functional theory. Global and local reactivity descriptors are used to study the chemical reactivity of the molecule. Chemical reactivity parameters show that MD II is softer and chemically more reactive than MD I and MD III. Topological parameters at bond critical points (BCP) have been evaluated by ‘Quantum theory of atoms in molecules’ (QTAIM). The docking studies revealed that the active sites C=O of MD showed best binding energies of −5.17, −5.43, −4.31,-4.77, −5.86 and −4.77for 5O3L, 1HTM, 3UV5, 5I1Q, 1MU7 and 1QZQ respectively, which are bacterial proteins of Escherichia coli.

Theoretical study on the elimination kinetics in the gas phase of allyl methyl compounds

The thermal decomposition kinetics of allyl methyl amine, allyl methyl ether, and allyl methyl sulfide in the gas phase has been studied theoretically using the M06-2x/aug-cc-pVTZ quantum chemical approach. The observed activation parameters are consistent with a concerted unimolecular mechanism involving a non-planar cyclic six-membered transition state. Based on the optimized ground state geometries, a natural bond orbital analysis of donor–acceptor interactions reveals that the stabilization energies corresponding to the electronic delocalization from the lone-pair (LP) non-bonding orbitals on the heteroatom to the neighboring $$\sigma_{{{\text{C2}} - {\text{C3}}}}^{*}$$ antibonding orbitals decrease from allyl methyl amine to allyl methyl sulfide. This delocalization fairly explains the increase of occupancies of LP orbitals on the heteroatom from allyl methyl sulfide to allyl methyl amine. The results also suggest that the kinetics of the thermolysis of the studied compounds are dominated by $${\text{LP}}\, \to \,\sigma^{*}$$ electronic delocalization effects. Analysis of bond order, bond indices, and synchronicity parameters demonstrates that these reactions proceed through a concerted and slightly asynchronous mechanism.

Angular Dependence of Strong Field Ionization of Haloacetylenes HCCX (X = F, Cl, Br, I), Using Time-Dependent Configuration Interaction with an Absorbing Potential

Strong field ionization of haloacetylenes was simulated by time-dependent configuration interaction using all single excitations and a complex absorbing potential. The angular dependence of ionization for HCCX was mapped with static electric fields in the range 0.01–0.06 atomic units and compared with the results for CH3X. HCCF ionizes primarily from the CC π orbital. HCCX (X = Cl, Br, I) compounds show increasing amounts of ionization from the halogen π-type lone pair orbitals and have a node perpendicular to the molecular axis. These shapes can be understood in terms of the energies and interactions of the halogen π-type lone pairs with the π orbitals of the CC triple bond.

Frank Mallory

Frank Mallory, 84, died on Nov. 7, 2017, in Bryn Mawr, Pa. “Frank, a longtime ACS member and chair of the chemistry department at Bryn Mawr College, was a passionate chemist and scholar, a dedicated educator of undergraduate and graduate students, a talented musician (clarinet)—he was often asked to play with chamber groups at national and international chemistry meetings—and a steadfast supporter of his family and friends. He is best known professionally for establishing the phenomenon of ‘through-space’ NMR coupling attributed to the spatial overlap of two lone pair orbitals, and for the photoisomerization/cyclization of stilbenes, a protocol now known as the Mallory reaction. Along with his wife, Sally, Frank published an all-inclusive account of stilbene cyclizations in Organic Reactions. Frank continued to work extensively in these areas until his retirement. That Frank was a superb undergraduate educator was attested to in 1992 when he was awarded the prestigious Lindback

Attosecond X-ray Diffraction Triggered by Core or Valence Ionization of a Dipeptide.

With the advancement of intense ultrafast X-ray sources, it is now possible to create a molecular movie by following the electronic dynamics in real time and real space through time-resolved X-ray diffraction. Here we employ real-time time-dependent density functional theory (RT-TDDFT) to simulate the electronic dynamics after an impulse core or valence ionization in the glycine-phenylalanine (GF) dipeptide. The time-evolving dipole moment, the charge density, and the time-resolved X-ray diffraction signals are calculated. The charge oscillation is calculated for 7 fs for valence ionization and 500 as for core ionization. The charge oscillation time scale is comparable to that found in a phenylalanine monomer (4 fs) [ Science 2014 , 346 , 336 ] and is slightly longer because of the elongated glycine chain. Following valence ionization, the charge migration across the GF is mediated by the delocalized lone-pair orbitals of oxygen and nitrogen of the electron-rich amide group. The temporal Fourier transform of the dipole moment provides detailed information on the charge migration dynamics and the molecular orbitals involved. Heterodyne-detected attosecond X-ray diffraction signals provide the magnitude and phase of the scattering amplitude in momentum space and can thus be inverted to yield the charge density in real space.

Identification and Characterization of Molecular Bonding Structures by ab initio Quasi-Atomic Orbital Analyses.

The quasi-atomic analysis of ab initio electronic wave functions in full valence spaces, which was developed in preceding papers, yields oriented quasi-atomic orbitals in terms of which the ab initio molecular wave function and energy can be expressed. These oriented quasi-atomic orbitals are the rigorous ab initio counterparts to the conceptual bond forming atomic hybrid orbitals of qualitative chemical reasoning. In the present work, the quasi-atomic orbitals are identified as bonding orbitals, lone pair orbitals, radical orbitals, vacant orbitals and orbitals with intermediate character. A program determines the bonding characteristics of all quasi-atomic orbitals in a molecule on the basis of their occupations, bond orders, kinetic bond orders, hybridizations and local symmetries. These data are collected in a record and provide the information for a comprehensive understanding of the synergism that generates the bonding structure that holds the molecule together. Applications to a series of molecules exhibit the complete bonding structures that are embedded in their ab initio wave functions. For the strong bonds in a molecule, the quasi-atomic orbitals provide quantitative ab initio amplifications of the Lewis dot symbols. Beyond characterizing strong bonds, the quasi-atomic analysis also yields an understanding of the weak interactions, such as vicinal, hyperconjugative and radical stabilizations, which can make substantial contributions to the molecular bonding structure.

Intramolecular hydrogen bonding in malonaldehyde and its radical analogues.

High level Brueckner doubles with triples correction method-based ab initio calculations have been used to investigate the nature of intramolecular hydrogen bonding and intramolecular hydrogen atom transfer in cis-malonaldehyde (MA) and its radical analogues. The radicals considered here are the ones that correspond to the homolytic cleavage of C-H bonds in cis-MA. The results suggest that cis-MA and its radical analogues, cis-MARS, and cis-MARA, both exist in planar geometry. The calculated intramolecular O-H⋯O=C bond in cis-MA is shorter than that in the radical analogues. The intramolecular hydrogen bond in cis-MA is stronger than in its radicals by at least 3.0 kcal/mol. The stability of a cis-malonaldehyde radical correlates with the extent of electron spin delocalization; cis-MARA, in which the radical spin is more delocalized, is the most stable MA radical, whereas cis-MARS, in which the radical spin is strongly localized, is the least stable radical. The natural bond orbital analysis indicates that the intramolecular hydrogen bonding (O⋯H⋯O) in cis-malonaldehyde radicals is stabilized by the interaction between the lone pair orbitals of donor oxygen and the σ* orbital of acceptor O-H bond (n → σ*OH). The calculated barriers indicate that the intramolecular proton transfer in cis-MA involves 2.2 kcal/mol lower barrier than that in cis-MARS.

Relativistic Effect on 1J(M,C) in Me4M, Me3M−, Ph4M, and Ph3M− (M=Pb, Sn, Ge, Si, and/or C): Role of s‐Type Lone Pair Orbitals in the Distinct Effect for the Anionic Species

Indirect one-bond nuclear spin-spin couplings between M and C [1 J(M,C)] in Me4 M, Me3 M- , Ph4 M, and Ph3 M- (M=Pb, Sn, Ge, Si, C) are analyzed with consideration of the relativistic effect and by employing Slater-type basis sets. The evaluated total values 1 JTL (M,C) reproduced the observed values with some systematic calculation errors. Fermi contact terms 1 JFC (M,C) contribute predominantly to 1 JTL (M,C) (≈99 %). A distinct relativistic effect on 1 J(Pb,C) is predicted for Me3 Pb- and Ph3 Pb- . The mechanisms for the distinct effect are elucidated by using the comparison between Me3 Pb- and Me4 Pb as an example. The contributions to 1 JFC (M,C) [or 1 JSD+FC (M,C), where SD denotes the spin-dipolar term] are decomposed into those of occupied orbitals and occupied-to-unoccupied transitions. The s-type lone-pair orbitals are demonstrated to contribute to the distinct relativistic effect on 1 J(Pb,C) of Me3 Pb- (and Ph3 Pb- ). The results are in sharp contrast to the cases of 1 J(M,C) for M atoms lighter than Pb, such as Si, and are explained by the s character of the M-C bonds. This treatment enables visualization and clear recognition the origin of the nuclear couplings for the species exhibiting a relativistic effect.

The Bonding Situation in Metalated Ylides.

Quantum chemical calculations have been carried out to study the electronic structure of metalated ylides particularly in comparison to their neutral analogues, the bisylides. A series of compounds of the general composition Ph3P−C−L with L being either a neutral or an anionic ligand were analyzed and the impact of the nature of the substituent L and the total charge on the electronics and bonding situation was studied. The charge at the carbon atom as well as the dissociation energies, bond lengths, and Wiberg bond indices strongly depend on the nature of L. Here, not only the charge of the ligand but also the position of the charge within the ligand backbone plays an important role. Independent of the substitution pattern, the NBO analysis reveals the preference of unsymmetrical bonding situations (P=C−L or P−C=L) for almost all compounds. However, Lewis structures with two lone‐pair orbitals at the central carbon atom are equally valid for the description of the bonding situation. This is confirmed by the pronounced lone‐pair character of the frontier orbitals. Energy decomposition analysis mostly reveals the preference of several bonding situations, mostly with dative and ylidic electron‐sharing bonds (e.g., P→C−−L). In general, the anionic systems show a higher preference of the ylidic bonding situations compared to the neutral analogues. However, in most of the cases different resonance structures have to be considered for the description of the “real” bonding situation.

Direct Pathway to Molecular Photodissociation on Metal Surfaces Using Visible Light.

We demonstrate molecular photodissociation on single-crystalline metal substrates, driven by visible-light irradiation. The visible-light-induced photodissociation on metal substrates has long been thought to never occur, either because visible-light energy is much smaller than the optical energy gap between the frontier electronic states of the molecule or because the molecular excited states have short lifetimes due to the strong hybridization between the adsorbate molecular orbitals (MOs) and metal substrate. The S-S bond in dimethyl disulfide adsorbed on both Cu(111) and Ag(111) surfaces was dissociated through direct electronic excitation from the HOMO-derived MO (the nonbonding lone-pair type orbitals on the S atoms (nS)) to the LUMO-derived MO (the antibonding orbital localized on the S-S bond (σ*SS)) by irradiation with visible light. A combination of scanning tunneling microscopy and density functional theory calculations revealed that visible-light-induced photodissociation becomes possible due to the interfacial electronic structures constructed by the hybridization between molecular orbitals and the metal substrate states. The molecule-metal hybridization decreases the gap between the HOMO- and LUMO-derived MOs into the visible-light energy region and forms LUMO-derived MOs that have less overlap with the metal substrate, which results in longer excited-state lifetimes.