Au Interactions Research Articles

How to induce superconductivity in epitaxial graphene via remote proximity effect through an intercalated gold layer

Graphene holds promises for exploring exotic superconductivity with Dirac-like fermions. Making graphene a superconductor at large scales is however a long-lasting challenge. A possible solution relies on epitaxially-grown graphene, using a superconducting substrate. Such substrates are scarce, and usually destroy the Dirac character of the electronic band structure. Using electron diffraction (reflection high-energy, and low-energy), scanning tunneling microscopy and spectroscopy, atomic force microscopy, angle-resolved photoemission spectroscopy, Raman spectroscopy, and density functional theory calculations, we introduce a strategy to induce superconductivity in epitaxial graphene via a remote proximity effect, from the rhenium substrate through an intercalated gold layer. Weak graphene–Au interaction, contrasting with the strong undesired graphene–Re interaction, is demonstrated by a reduced graphene corrugation, an increased distance between graphene and the underlying metal, a linear electronic dispersion and a characteristic vibrational signature, both latter features revealing also a slight p doping of graphene. We also reveal that the main shortcoming of the intercalation approach to proximity superconductivity is the creation of a high density of point defects in graphene (1014 cm−2). Finally, we demonstrate remote proximity superconductivity in graphene/Au/Re(0001), at low temperature.

How does the addition of shape distinct gold nanoparticles influence on the conformational transition of poly(N-isopropylacrylamide)?

HypothesisThe subject of nanomaterials has created immense interest and expectations in the field of science and nanotechnology. Plentiful aspects proposed by gold nanoparticles (AuNPs) and their capability to affect macromolecular transition is the main driving force to execute the current study. A thermo-responsive polymer poly(N-isopropylacrylamide) (pNIPAM) is studied in presence of nanoparticles, particularly gold nanorods and nanospheres to elucidate completely the effect of their shape, surface area and structural morphology on the conformation of pNIPAM. ExperimentsIn this respect, several biophysical techniques such as fluorescence spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) are utilized to examine the interaction of Au nanospheres/nanorods with pNIPAM. For a better understanding of Au nanoparticles morphology, transmission electron microscopy (TEM) is also employed. FindingsIntroducing gold nanoparticles with the polymeric solution promotes the polymer to stay in the coil conformation at a higher temperature than the LCST of aqueous pNIPAM. A shift of 2 and 25.5 °C in the LCST of pNIPAM is observed along with Au nanospheres and nanorods, respectively. The current study provides a better impact in the field of biomedical science specifically drug delivery and tissue engineering as the LCST approaches human body temperature.

Strain and Charge Doping Fingerprints of the Strong Interaction between Monolayer MoS2 and Gold.

Gold-mediated exfoliation of MoS2 has recently attracted considerable interest. The strong interaction between MoS2 and Au facilitates preferential production of centimeter-sized monolayer MoS2 with near-unity yield and provides a heterostructure system noteworthy from a fundamental standpoint. However, little is known about the detailed nature of the MoS2–Au interaction and its evolution with the MoS2 thickness. Here, we identify the specific vibrational and binding energy fingerprints of this interaction using Raman and X-ray photoelectron spectroscopy, which indicate substantial strain and charge doping in monolayer MoS2. Tip-enhanced Raman spectroscopy reveals heterogeneity of the MoS2–Au interaction at the nanoscale, reflecting the spatial nonconformity between the two materials. Micro-Raman spectroscopy shows that this interaction is strongly affected by the roughness and cleanliness of the underlying Au. Our results elucidate the nature of the MoS2–Au interaction and guide strain and charge doping engineering of MoS2.

Gold Complexes with Difunctional Perfluoroalkyl Chains: Quantifying the Energy of Aurophilic Interactions in Flexible Open‐Chain Complexes

AbstractThe first binuclear AuI compounds containing bridging (CF2)n chains (n=4, 6, 8) and AuIII metallaperfluorocyclopentanes have been obtained by photoinitiated reactions of LAuMe (L=PPh3, PMe3, PCy3, or IPr) with α,ω‐diiodoperfluorocarbons. Complexes LAu(CF2)4AuL present an unusual looped structure stabilized by an aurophilic interaction for L=PMe3, PPh3, and PCy3. The study of their dynamic behaviour has provided new insights about the strength of aurophilic interactions in solution, allowing quantification of the energy of a single Au⋅⋅⋅Au interaction.

Gold Complexes with Difunctional Perfluoroalkyl Chains: Quantifying the Energy of Aurophilic Interactions in Flexible Open-Chain Complexes.

The first binuclear AuI compounds containing bridging (CF2 )n chains (n=4, 6, 8) and AuIII metallaperfluorocyclopentanes have been obtained by photoinitiated reactions of LAuMe (L=PPh3 , PMe3 , PCy3 , or IPr) with α,ω-diiodoperfluorocarbons. Complexes LAu(CF2 )4 AuL present an unusual looped structure stabilized by an aurophilic interaction for L=PMe3 , PPh3 , and PCy3 . The study of their dynamic behaviour has provided new insights about the strength of aurophilic interactions in solution, allowing quantification of the energy of a single Au⋅⋅⋅Au interaction.

Hydride Transfer to Gold: Yes or No? Exploring the Unexpected Versatility of Au⋅⋅⋅H-M Bonding in Heterobimetallic Dihydrides.

The potential for coordination and H-transfer from Cp2 MH2 (M=Zr, W) to gold(I) and gold(III) complexes was explored in a combined experimental and computational study. [(L)Au]+ cations react with Cp2 WH2 giving [(L)Au(κ2 -H2 WCp2 )]+ (L=IPr (1), cyclic (alkyl)(amino)carbene (2), PPh3 (3) and Dalphos-Me (4) [IPr=1,3-bis(diisopropylphenyl)imidazolylidene; Dalphos-Me=di(1-adamantyl)-2-(dimethylamino)phenyl-phosphine], while [Au(DMAP)2 ]+ (DMAP=p-dimethylaminopyridine) affords the C2 -symmetric [Au(κ-H2 WCp2 )2 ]+ (5). The Dalphos complex 4 can be protonated to give the bicationic adduct 4 H, showing AuI ⋅⋅⋅H+ -N hydrogen bonding. The gold(III) Lewis acid [(C^N-CH)Au(C6 F5 )(OEt2 )]+ binds Cp2 WH2 to give an Au-H-W σ-complex. By contrast, the pincer species [(C^N^C)Au]+ adds Cp2 WH2 by a purely dative W→Au bond, without Au⋅⋅⋅H interaction. The biphenylyl-based chelate [(C^C)Au]+ forms [(C^C)Au(μ-H)2 WCp2 ]+ , with two 2-electron-3-centre W-H⋅⋅⋅Au interactions and practically no Au-W donor acceptor contribution. In all these complexes, strong but polarized W-H bonds are maintained, without H-transfer to gold. On the other hand, the reactions of Cp2 ZrH2 with gold complexes led in all cases to rapid H-transfer and formation of gold hydrides. Relativistic DFT calculations were used to rationalize the striking reactivity and bonding differences in these heterobimetallic hydride complexes along with an analysis of their characteristic NMR parameters and UV/Vis absorption properties.

Green and transparent cellulose nanofiber substrate-supported luminescent gold nanoparticles: A stable and sensitive solid-state sensing membrane for Hg(II) detection

Mercury(II) pollution is a growing threat to the environment and humanity. But most of the solution-based Au nanomaterial sensors suffer from low stability seriously. Here, inspired by high-affinity metallophilic Hg2+–Au(I) interaction mechanism, we introduced a transparent cellulose nanofiber matrix-supported luminescent gold nanoparticle (AuNPs) stable sensing membrane. In this solid-state membrane, the AuNPs with strong red fluorescence emission were synthesized as the sensor unit. Cellulose nanofibrilatted (CNF) matrix was fabricated as the supporting substrate. With a large specific surface area, the nanostructured CNF matrix offers abundant immobilizing spots to the sensor unit of AuNPs. More importantly, the excited fluorescence can escape directly without apparent scattering loss due to the high transparency of the CNF substrate. With strong emission of the AuNPs, coupled with abundant AuNP immobilizing spots and high transparency of the CNF substrate, the fluorescence signaling path was manipulated sequentially from signal generation, transmission until to quenching, resulting in the membrane demonstrates high sensitivity, selectivity, and stability. The detection limit of 1.0 nM is markedly lower than the threshold level of 10.0 nM permitted by US EPA. Aided with the high-performance membrane, the detection of Hg(II) becomes simple, fast, easy handing, and green. We envision the membrane will be an attractive material for Hg(II) monitor.

Systematic Study on Sensing Capability of Gold(I) Pyrazolate Complex for Vapochromic Chemosensors of Ethanol Vapors

Modified gold complexes as dinuclear adducts with silver bridge ions, clusters with other metal ions, and bimetallic sandwiches have shown better sensing capabilities for vapochromic chemosensing of organic vapors than its unmodified structure. Herein, a simple gold(I) complex, synthesized from 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand, have been shown to have higher sensing capability toward ethanol (EtOH) vapors. Such sensing capability can be possibly achieved when EtOH vapors have enough time to diffuse to the main sensing sites of the sensor. Thus, 80 to 160 µL (with 20 µL increment) of EtOH vapors were exposed to the synthesized gold(I) pyrazolate complex at varied distances of 2.75, 11 and 22 cm for 15 minutes. The complex displayed its sensing capability by quenching at its emission intensity of 600 nm up to 80%, which suggests the possible interaction of the EtOH vapors with the inner sensing site originated from the Au(I)–Au(I) interaction of the complex where it is possible to breakdown the light-emitting capability. Prior to this interaction, there was only a slight blue-shifting of 9 nm away from its emission intensity by the binding of EtOH vapors to the methoxy of benzene ring hence only demonstrating weak sensing capability. These results indicated that sensing capability as shown by the quenching phenomenon at the emission intensity of gold(I) complex is dependent on diffusion time of EtOH vapors.

Influence of pressure on the structure and luminescence properties of AMP-protected gold nanoparticles as revealed by fluorescence spectra and 2D correlation analysis

In the present study we have applied in situ fluorescence spectroscopy, in combining with two-dimensional correlation spectroscopy (2DCOS), to investigate the dynamic fluorescence changes of adenosine 5′-monophosphate capped gold nanoclusters (AuNCs@AMP) versus pressure in solid. Several weak and overlapped spectral components, developed with pressure, are differentiated and assigned in detailed by 2DCOS analysis. In addition, the sequential spectral variations are also revealed, which take place as follows. The ligands-surface Au(I) (denoting as 450, 480 nm), surface Au(I)⋯Au(I) (as 515, 520 and 565 nm), and even the inner metal core Au–Au interactions (as 605 nm), take place at pressure range from low to high. Moreover, the pressure-induced luminescence performance is also compared between AuNCs@AMP being prepared at 60 and 80 °C, respectively. It implies that it is more stable for AuNCs prepared at 60 °C as which has better pressure tolerance. Finally, it is confirmed that the orientation of AMP at the gold surface plays a crucial role in the tuning of luminance performance, especially the emission intensity to compression.

Synthesis and Reactivity of (NHC)AuI–Mercaptopyridine Complexes

Reaction of (NHC)Au–X (X = halide) complexes with 2- or 4-mercaptopyridine under basic conditions allows for the preparation of a series of (NHC)AuI–mercaptopyridine complexes 1–4 in high yields. All complexes have been fully characterized by means of 1H and 13C NMR spectroscopy, melting point, and elemental analysis. Single crystals of complexes 1–3 were obtained, and the solid-state structures display a linear Au(I) center with coordination to the NHC ligand and the sulfur atom of the mercaptopyridine moiety. Interestingly, weak γ-anagostic C–H···Au interactions are found in complexes 1–3 regardless of the relative N or S position in the mercaptopyridine. Taking advantage of the free pyridine nitrogen, reaction of complexes 1 and 2 with palladium allyl chloride dimer permits the isolation of heteronuclear Au/Pd complexes 5 and 8 featuring a bridging ambidentate mercaptopyridine ligand. Further reactivity of complexes 1–3 toward B(C6F5)3 produces complexes 6, 7, and 9, which display frustrated Lewis pair reactivity with the activation of a H–F bond.

Comparative Analysis of Au and Au@SiO2 Nanoparticle-Protein Interactions for Evaluation as Platforms in Theranostic Applications.

Gold nanoparticles are utilized in a variety of sensing and detection technologies because of their unique physiochemical properties. Their tunable size, shape, and surface charge enable them to be used in an array of platforms. The purpose of this study is to conduct a thorough spectroscopic characterization of Au and functionalized hybrid Au@SiO2 nanoparticles under physiological conditions and in the presence of two proteins known to be abundant in serum, bovine serum albumin and human ubiquitin. The information obtained from this study will enable us to develop design principles to synthesize an array of surface-enhanced Raman spectroscopy-based nanoparticles as platforms for theranostic applications. We are particularly interested in tailoring the surface chemistry of the Au@SiO2 nanoparticles for applications in theranostic technologies. We employ common spectroscopic techniques, with particular emphasis on circular dichroism and heteronuclear single quantum correlation nuclear magnetic resonance (HSQC NMR) spectroscopy, as combinatorial tools to understand protein conformational dynamics, binding site interactions, and protein corona for the design of nanoparticles capable of reaching their intended target in vivo. Our results conclude that protein adsorption onto the nanoparticle surface prevents nanoparticle aggregation. We observed that varying the ionic strength and type of ion influences the aggregation and aggregation rate of each respective nanoparticle. The conformation of proteins and the absorption of proteins on the surface of Au nanoparticles are also influenced by ionic strength. Using two-dimensional [15N–1H]-HSQC NMR experiments to compare the interactions of Au and Au@SiO2 nanoparticles with 15N-ubiquitin, we observed small chemical shift perturbations in some amino acid peaks and differences in binding site interactions with ubiquitin and respective nanoparticles.

Macrocyclic dimer of Fc(NHC(O)PPh2-AuCl)2 induced by aurophilic interactions, and chirality induction into Fc core

The reaction of 1,1′-bis(diphenylphosphinecarboxamidyl)ferrocene, Fc(NHC(O)PPh2)2 L, with chloro(tetrahydrothiophene)gold(I), [AuCl(tht)], was found to afford the macrocyclic dimer gold(I) complex, {Fc(NHC(O)PPh2-AuCl)2}21, induced by aurophilic interactions. The macrocyclic dimer gold(I) complex 1 gave needle 1needle and plate 1plate crystals. The single-crystal X-ray structure determination of 1 was demonstrated to reveal the self-association properties of the gold(I) and the phosphinecarboxamide moieties in the solid state. The macrocyclic dimer gold(I) complex 1needle crystallized in the space group C2/c with P- and M-helical chirality of the ferrocene (Fc) core. Both conformational enantiomers were found to form homochiral PP and MM macrocyclic dimers, respectively, through intermolecular aurophilic Au(I)–Au(I) interactions and hydrogen bonds between the NH of the phosphinecarboxamide moiety and the Cl of AuCl of the other molecule, wherein PP and MM macrocyclic dimers induced S- and R-conformational enantiomers based on the torsional twist about the Au(I)–Au(I) axis, respectively. The macrocyclic dimer gold(I) complex 1plate crystallized in the space group P21/c with heterochiral PM macrocyclic dimer through aurophilic Au(I)–Au(I) interactions with R- and S- conformational enantiomers. The macrocyclic dimer gold(I) complex 1 was found to bind halide ion of ammonium salt by using the phosphinecarboxamide binding sites. The addition of l-proline methyl ester hydrochloride to the solution of 1 was demonstrated to induce the P-helical chirality of the Fc core.

Reversible Solid-State Phase Transitions between Au-P Complexes Accompanied by Switchable Fluorescence.

Six complexes {(3-bdppmapy)(AuCl)2}n (1-6; 3-bdppmapy = N,N'-bis(diphenylphosphanylmethyl)-3-aminopyridine and tht = tetrahydrothiophene) were simultaneously formed by the reaction of Au(tht)Cl and 3-bdppmapy in CH2Cl2 followed by infusion with hexane. Complexes 4-6 could be produced independently by volatilizing solvent in air, solid-state heating, or solvothermal reaction. The PPh2-Au-Cl moieties extended in different directions, forming Au-Au and Au-Au-Au interactions. Complex 4 could be converted to 5 by heating to 130 °C, with the cleavage of one Au-Au bond, while 5 reverted back to 4 upon exposure to CH2Cl2 vapor over 11 h. This solid-state phase transition could be recycled and was accompanied by a change in solid-state fluorescence, without obvious intensity decay over five cycles. The reason for both the phase transition and difference in photoluminescence is related to the different numbers and strengths of aurophilic interactions in each complex that could be modeled by density functional theory calculations.

Enhanced Metallophilicity in Metal-Carbene Systems: Stronger Character of Aurophilic Interactions in Solution.

Metallophilicity is an essential concept that builds upon the attraction between closed shell metal ions. We report on the [M2 (bisNHC)2 ]2+ (M=AuI , AgI ; NHC=N-heterocyclic carbene) systems, which display almost identical features in the solid state. However, in solution the Au2 cation exhibits a significantly higher degree of rigidity owed to the stronger character of the aurophilic interactions. Both Au2 and Ag2 cationic constructs are able to accommodate Ag+ ions via M-M interactions, despite their inherent Coulombic repulsion. When electrostatic repulsion between host and guest is partially diminished, M-M distances are substantially shortened. Quantum chemical calculations estimate intermetallic bond orders up to 0.2. Although at the limit of (or beyond) the van der Waals radii, metallophilic interactions are responsible for their behavior in solution.

Towards the understanding of the gold interaction with AIII-BV semiconductors at the atomic level.

AIII-BV semiconductors have been considered to be a promising material for decades in overcoming the limitations of silicon semiconductor devices. One of the important aspects within the AIII-BV semiconductor technology is gold-semiconductor interactions on the nanoscale. We report on the investigations into the basic chemical interactions of Au atoms with AIII-BV semiconductor crystals by the investigation of the nanostructure formation in the process of thermally-induced Au self-assembly on various AIII-BV surfaces by means of atomically resolved High Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM) measurements. We have found that the formation of nanostructures is a consequence of the surface diffusion and nucleation of adatoms produced by Au induced chemical reactions on AIII-BV semiconductor surfaces. Only for InSb crystals we have found that there is efficient diffusion of Au atoms into the bulk, which we experimentally studied by Machine Learning HAADF STEM image quantification and theoretically by Density Functional Theory (DFT) calculations with the inclusion of finite temperature effects. Furthermore, the effective number of Au atoms needed to release one AIII metal atom has been estimated. The experimental finding reveals a difference in the Au interactions with the In- and Ga-based groups of AIII-BV semiconductors. Our comprehensive and systematic studies uncover the details of the Au interactions with the AIII-BV surface at the atomic level with chemical sensitivity and shed new light on the fundamental Au/AIII-BV interactions at the atomic scale.

Pd-Promoted cross coupling of iodobenzene with vinylgold via an unprecedented phenyl transmetalation from Pd to Au.

A novel Pd/Au vinylene complex synthesized through cyclization of σ,π-heterodinuclear (Pd/Au) acetylide reacted with iodobenzene to give a Pd vinyl species, where the presence of a strong metallophilic PdAu interaction was found to facilitate phenyl transmetalation from Pd to Au, followed by reductive elimination at Au.

Aurophilicity-Mediated Construction of Emissive Porous Molecular Crystals as Versatile Hosts for Liquid and Solid Guests.

The first examples of porous molecular crystals that are assembled through Au⋅⋅⋅Au interactions of gold complex 1 are here reported along with their exchange properties with respect to their guest components. Single-crystal X-ray diffraction (XRD) analyses indicate that the crystal structure of 1/CH2 Cl2 ⋅pentane is based on cyclic hexamers of 1, which are formed through six Au⋅⋅⋅Au interactions. The packing of these cyclic hexamers affords a porous architecture, in which the one-dimensional channel segment contains CH2 Cl2 and pentane as guests. These guests can be exchanged through operationally simple methods under retention of the host framework of 1, which furnished 1/guest complexes with 26 different guests. A single-crystal XRD analysis of 1/eicosane, which contains the long linear alkane eicosane (n-C20 H42 ), successfully provided its accurately modeled structure within the porous material. These host-guest complexes show chromic luminescence with both blue- and redshifted emissions. Moreover, this porous organometallic material can exhibit luminescent mechanochromism through release of guests.

Multiresponsive Luminescent Cationic Cyclometalated Gold(III) Amphiphiles and Their Supramolecular Assembly.

A new class of amphiphilic tridentate cyclometalated gold(III) complexes has been designed and synthesized as luminescent supramolecular building blocks. Positively charged trimethylammonium (-CH2NMe3+) containing alkynyl ligands have been incorporated to introduce the electrostatic interactions. The X-ray crystal structures of two of the complexes have been determined, and the existence of π-π interactions between molecules has been observed. Steady-state and time-resolved absorption and emission studies have been carried out to investigate the nature of the excited states. The complexes are found to exhibit self-assembly properties with the assistance of π-π stacking and hydrophobic interactions and possibly weak Au···Au interaction, resulting in notable emergence of low-energy absorption bands and luminescence changes. The presence of a large hydrophobic moiety is found to be crucial for the formation of aggregates, especially in polar media where hydrophobic interactions play an important role. The nature of the counterion has been shown to have a significant effect on the extent of self-assembly in different media. Upon aggregation, nanofibers are formed in polar media, while nanorods are observed in nonpolar media in one of the representative complexes. Interestingly, a small modification on the alkynyl ligand resulted in the formation of nanoribbons instead. Intriguing luminescence mechanochromic properties have also been observed. This orthogonal and rational molecular design strategy has been shown to be effective in the construction of gold(III)-based smart and multiresponsive materials.

New Evidence of the Bidentate Binding Mode in 3-MBA Protected Gold Clusters: Analysis of Aqueous 13-18 kDa Gold-Thiolate Clusters by HPLC-ESI-MS Reveals Special Compositions Aun(3-MBA)p, (n = 48-67, p = 26-30).

Gold clusters protected by 3-MBA ligands (MBA = mercaptobenzoic acid, –SPhCO2H) have attracted recent interest due to their unusual structures and their advantageous ligand-exchange and bioconjugation properties. Azubel et al. first determined the core structure of an Au68-complex, which was estimated to have 32 ligands (3-MBA groups). To explain the exceptional structure-composition and reaction properties of this complex, and its larger homologs, Tero et al. proposed a “dynamic stabilization” via carboxyl O–H––Au interactions. Herein, we report the first results of an integrated liquid chromatography/mass spectrometer (LC/MS) analysis of unfractionated samples of gold/3-MBA clusters, spanning a narrow size range 13.4 to 18.1 kDa. Using high-throughput procedures adapted from bio-macromolecule analyses, we show that integrated capillary high performance liquid chromatography electrospray ionization mass spectrometer (HPLC-ESI-MS), based on aqueous-methanol mobile phases and ion-pairing reverse-phase chromatography, can separate several major components from the nanoclusters mixture that may be difficult to resolve by standard native gel electrophoresis due to their similar size and charge. For each component, one obtains a well-resolved mass spectrum, nearly free of adducts or signs of fragmentation. A consistent set of molecular mass determinations is calculated from detected charge-states tunable from 3− (or lower), to 2+ (or higher). One thus arrives at a series of new compositions (n, p) specific to the Au/3-MBA system. The smallest major component is assigned to the previously unknown (48, 26); the largest one is evidently (67, 30), vs. the anticipated (68, 32). Various explanations for this discrepancy are considered. A prospective is given for the various members of this novel series, along with a summary of the advantages and present limitations of the micro-scale integrated LC/MS approach in characterizing such metallic-core macro-molecules, and their derivatives.

Aromatic versus aliphatic thiols on Au(111) surface: a DFT exploration of adsorption registry and electronic structure

ABSTRACTSelf-assembled monolayers (SAMs) on metal surfaces have inspired many interesting applications, such as chemical and biological sensors, molecular electronics, magnetism and protective coatings. In this respect, SAMs having different head and tail groups have been synthesised which allow the modification of the material properties by tuning intermolecular, monolayer–metal and/or monolayer–solvent interactions. In this respect, we investigate the adsorption of thiols having aromatic, p-mercaptobenzonitrile (pPhCN) or aliphatic, 2-azidoethanthiol (N3S), tail groups on Au(111) surface by means of Density Functional Theory (DFT). Monomer and dimer adsorption configurations of both pPhCN and N3S molecules as well as the modification of the electronic structures upon adsorption are studied. Our results show that different adsorption mechanisms are observed for the molecules under consideration. While monomer and dimer structures of the pPhCN prefer to adsorb laterally on the surface, for N3S vertical arrangement of the molecules enhances the molecular immobilisation. Although, dominant contributions to the adsorption energy of the laterally adsorbed pPhCN are through S–Au chemical bond, phenyl ring–surface and cyano N–surface interactions, π–π stacking of the rings contributes to the stabilisation of the complex in addition to the S–Au chemical bond in the case of vertical attachment. For N3S, on the other hand, only S–Au chemical bond determines the adsorption strength. S–Au interactions result in broad molecular orbital redistribution of the S atoms of both molecules, due to the rehybridisation of S and Au states. Density of cyano-N and cyano-C states present in the pPhCN is affected by the orientation of the rings with respect to each other. In the case of 2N3S, instead, the distribution of the tail group molecular orbitals is not modified by the adsorption.