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BY 4.0 license Open Access Published by De Gruyter Open Access September 25, 2019

The influence of the grafted aryl groups on the solvation properties of the graphyne and graphdiyne - a MD study

  • Avni Berisha EMAIL logo
From the journal Open Chemistry

Abstract

The mechanism of the adsorption and grafting of diazonium cations onto the surface of graphyne and graphdiyne was investigated using Density Functional Theory (DFT). The adsorption energy (both in vacuum and water as solvent) of the phenyl diazonium cation was evaluated at three different positions of the graphyne and graphdiyne surface. Moreover, the lowest energy adsorption sites were used to calculate and plot Non-covalent Interactions (NCI). The Bond Dissociation Energy (BDE) results (up to 66 kcal/mol) for the scission of the phenyl group support the remarkable stability of the grafted layer. As both of these materials are non-dispersible in aqueous solution, in this work through the use of Molecular Mechanics (MM) and Molecular Dynamics (MD) we explored also the effect of the grafted substituted aryl groups derived from aryldiazonium salts onto the solvation properties of these materials.

1 Introduction

It is now well established that the aryl diazonium cations are the most promising candidates for the surface modification of materials. The use of such molecules for the surface modification dates in the 90’s from the ground-breaking work of Prof. Pinson [1]. In comparison to other molecules used for this purpose (thiols, silanes, phosphonic acids) [2] aryl diazonium salts are easy to synthesize and can be applied in a variety of materials (oxides, insulator, powders, polymers, metals, etc) a feature that is absent in the case of other molecules [3,4].

The surface modification reaction in the case of the diazonium salts is based on the attack of the very reactive aryl radical that is created upon scission of nitrogen moiety from the parent aryldiazonium cations. The formed interface (by spontaneous [5, 6, 7], electrochemical [1, 4, 10, 11, 12], sono-chemical [13], thermal [13,14] or light-driven de-diazonation [15] reactions) has been analyzed using immense number of analytical characterization methods (AFM, Tof-SIMS, XPS, RBS, IRRAS, TGA) [3,16]. The existence of the covalent binding between the grafted moiety and the material is supported both by experimental evidence [3], [16] and also using DFT calculations [9,17,18]. Up to now, to our knowledge, no existing study is focused toward the surface modification of graphyne and graphdiyne by aryl radicals derived from de-diazonation reactions of the aryldiazonium cations. In contrast, there are numerous studies were the aryldiazonium chemistry is applied for the modification of other carbon like nanomaterials [19, 20, 21, 22, 23, 24, 25]. Such study is of immense interest as graphyne and graphdiyne represent the two newest members of the very large family of nanocarbon allotropic materials that possess a lot of potential for use in the materials science. Both of these structures are one-atomic thick materials composed of sp2 and sp atoms, in which the adjacent benzene rings are linked in a huge network by one (in graphyne) or two acetylenic groups (in case of graphdiyne). Graphyne and graphydine are both members of the very large family of nanocarbon allotropic materials [0D (fullerenes, quantum dots, graphene dots, carbon dots, onion-like carbon, nano-diamonds), 1D (single-walled and multi-walled nanotubes, nanohorns), 2D (graphene, multilayered graphitic sheets, graphene oxide) and 3D (graphite), their surface modification using aryldiazonium salts is supposed to proceed in a similar way as with other carbon-rich nanomaterials [19, 20, 22, 24]. They are promising materials for a number of applications (gas separation, lithium storage, as a possible replacement material for silicon transistor technology etc.) since they pose a number of remarkable properties (extreme hardness, very high electric conductivity, high thermal resistance, etc.). In order to gain mechanistic details, interface stability of the grafted layers derived from aryl diazonium salts and their practical utility oriented toward the tuning of solvation properties of the grafted structures DFT [26, 27], molecular mechanics [28], and molecular dynamic calculations were employed. This represents the first study that addresses the impact of surface modification and the influence of the grafted aryl groups on the solvation properties of the graphyne and graphdiyne.

2 Computational details

2.1 DFT

DFT calculations were performed using the DMol3 software (BIOVIA). The graphyne and graphydine models used to compute the Bond Dissociation Energy and the solvation properties are presented in Figure 1. The models consist of a central phenyl ring (in green) linked to six other groups via -C≡C- (graphyne) or -C≡C-C≡C- (graphdiyne) linkages. All electron calculations are employed for geometry optimization with the double numerical plus polarization basis set (DNP) [29]. The exchange-correlation energy is described by the Perdew–Burke–Ernzerhof functional within the generalized gradient approximation (GGA– PBE) [9,30,31].

Figure 1 A. Graphyne and B. Graphdiyne structure used for DFT calculations.
Figure 1

A. Graphyne and B. Graphdiyne structure used for DFT calculations.

All energy minima were characterized by performing a vibrational analysis to ensure the lack of imaginary frequencies [9],[18].

The adsorption energy (Eads.) [9],[32] was calculated as:

E(ads.)=(EGraphneorGraphdiyne/arydiazoniumcation++EaryldiazoniumcationEGraphyneorGraphdiyne)

where: EGraphyne or Graphdiyne /aryldiazonium cation is the total energy of the adsorption system. EGraphyne or Graphdiyne and Earyldiazonium cation are the energies of the isolated Graphyne or Graphydine and aryldiazonium cations, respectively. The transition state (in water, using COSMO solvation model [33]) is computed using the combination of Linear Synchronous Transit (LST) and Quadratic Synchronous Transit (QST) [34].The NCI (Non-Covalent interaction) were computed using Multiwfn software [35] from the DFT calculations [B3LYP/6-311++g (d,p)]. The same was applied also to calculate the homolytic bond dissociation energy of the phenyldiazonium cation (using the bond scan). The NCI surface is plotted using VMD (Visual Molecular Dynamics) software [36].

2.2 Molecular Mechanics / Molecular Dynamics

Model systems for bare and modified graphyne and graphydyne structures were constructed as amorphous three-dimensional periodic boxes using the Amorphous Cell Tool in Materials Studio. The simulation cells enclosed 200 solvent molecules (either water or hexane). The steps used to compute solvation energies are presented in the Figure 2. The calculation was performed using the COMPASS II force field [37].

Figure 2 Step used to calculate the solvation energy for graphyne.
Figure 2

Step used to calculate the solvation energy for graphyne.

The total solvation free energy is calculated as the sum of three contributions: Ideal, van der Waals, and Electrostatic. The partition-coefficient Log P, was calculated using the equation:

logP=0.434AwaterAhexane/RT

where 0.434 corresponds to 10log e, R is the gas constant (1.987*10−3 kcal/mol/K), T the temperature in the simulation (298 K), and A[water or hexane] is the solvation free energy in water or hexane.

Ethical approval: The conducted research is not related to either human or animal use.

3 Results and discussion

From the Figure 3, the adsorption energies for the phenyl diazonium cation (PhN2+) onto the graphyne surface in a vacuum are in the range from -28.72 to -24.61 kcal/mol depending on the adsorption site. In the presence of water as the solvent, the maximum adsorption energy is found for the adsorption position 3 (where the phenyldiazonium cation is flat onto the central phenyl ring of graphyne with the diazonium group oriented above the alkyne bond) with the value of -14.85 kcal/mol. The similar trend in adsorption energy is also observed for the graphdyine structure, in this case again the maximum adsorption energy (in water) is found for the third adsorption position with the energy value of -14.62 kcal/mol.

Figure 3 Adsorption energy of phenyldiazonium cation (in water and vacuum) at 3 different adsorption sites onto A. Graphyne and B. Graphdiyne.
Figure 3

Adsorption energy of phenyldiazonium cation (in water and vacuum) at 3 different adsorption sites onto A. Graphyne and B. Graphdiyne.

In order to understand the adsorption details, the NCI 2D and 3D plots for the interaction of PhN2+ with both surfaces were computed (Figure 3) [35],[38]. The result shows that the adsorption is done through the van der Walss interactions. This interaction is considerably stronger than a simple π-π stacking (for which a gas phase value for such interaction is in the case of benzene are in the range of 2-3 kcal/mol) [39]. Understanding the adsorption of the aryldiazonium cations if of great interest to gain insights regarding the grafting of phenyl radicals that are the product of aryldiazonium cation induced or spontaneous de-diazonation reactions [4]. It is believed, that prior to the grafting reaction the adsorption of the diazonium cations takes place [4], this claim is supported by the obtained results (Figure 3 and 4).

Figure 4 Non-covalent interaction surfaces and the plot of Reduced Density Gradient (RDG) vs. sign(λ)ρ for the interaction of A. Graphyne/Ph-N2+ and Graphdiyne/Ph-N2+.
Figure 4

Non-covalent interaction surfaces and the plot of Reduced Density Gradient (RDG) vs. sign(λ)ρ for the interaction of A. Graphyne/Ph-N2+ and Graphdiyne/Ph-N2+.

The grafting reactions are essential for surface tuning of materials and add many interesting properties to them. For the practical applications, the grafted layers need to own certain stability. An indirect measure to asses such stability is the Bond Dissociation Energy (BDE) between the bonded aryl radical and the grafted moiety (in this case Graphene). For the BDE calculation, three different grafting positions were explored (Figure 5). The highest BDE values are obtained for the grafting position 2 with the BDE energy value of -66 kcal/mol. This value is much higher than the values obtained for the gold surface (up to -38 kcal/mol) reflecting much stronger interface stability. The BDE has similar value as in the case of grafted graphene oxide surface (when the phenyl moiety is attached directly on aromatic carbon), even though in comparison to this surface, the adsorption energy for the graphyne and graphdiyne is smaller [40].

Figure 5 BDEs computed in: vacuum and water (COSMO) for the bonding of phenyl- radicals on 3 distinctive grafting position onto Graphyne surface.
Figure 5

BDEs computed in: vacuum and water (COSMO) for the bonding of phenyl- radicals on 3 distinctive grafting position onto Graphyne surface.

In Figure 6 is presented the bond scission diagram for the homolytic de-diazonation of the phenyldiazonium cation:

Figure 6 Homolytic BDE of phenyl diazonium cations.
Figure 6

Homolytic BDE of phenyl diazonium cations.

PhN2+(aq)Ph(aq)+N2(aq)

The BDE, in this case, is 32.45 kcal/mol. From experimental studies on bulk carbon and other nanoscopic carbon, materials are known that the grafting takes place also spontaneously [6,7].

Thus, such reaction could be initiated through the instability of phenyldiazonium cation and further sustained (Figure 7) through the energy gain due to the difference between the reaction energy (-38.48 kcal/mol) and the energy barrier for the grafting reaction (34.17 kcal/mol) to take place.

Figure 7 BDEs computed in: vacuum and water (COSMO) for the bonding of phenyl- radicals on 3 distinctive grafting position onto Graphyne surface.
Figure 7

BDEs computed in: vacuum and water (COSMO) for the bonding of phenyl- radicals on 3 distinctive grafting position onto Graphyne surface.

The attached moieties derived from aryldiazonium cations (as calculated by Molecular Dynamics) have a certain impact on the solvation properties of graphyne (Figure 8). In this case, we took the solvation energy value of bare graphyne as zero in order to see only the effects of the grafted moieties on the solvation energy. The most pronounced effect is shown by the grafted Ph-COOH layers.

Figure 8 A. The solvation energy differences for the grafted graphyne structure (with two phenyl groups) in water and hexane. B. Calculated Log P values.
Figure 8

A. The solvation energy differences for the grafted graphyne structure (with two phenyl groups) in water and hexane. B. Calculated Log P values.

4 Conclusions

The adsorption of the phenyldiazonium cation and its subsequent grafting onto graphyne and graphdiyne surface was investigated using theoretical calculations for the first time. The computed NCI surfaces point out that the adsorption takes place by van der Waals interaction. The grafted phenyl group forms a quite stable interface with the BDE in the range of 66 kcal/mol pointing out to a covalent type of bonding. Taking into account the transition state calculations for the grafting of phenyl moiety onto the graphyne structure and the BDE from the formation of the phenyl radical from the corresponding aryldiazonium cation, the spontaneous surface modification is possible to take place. The Molecular Dynamics calculation, from which solvation properties and Log P can be computed clearly evidence the possibility to tune the solvation/dispersion properties of these structures by using aryldiazonium cations that bear polar or non-polar substituents. The present study not only provides a prospect to understand the grafting of aryl radicals onto graphyne and graphdiyne surface but also shows the benefits of the attached groups for tunning dispersibility of such structures.

Acknowledgments

The author gratefully acknowledges the support from the Ministry of Education, Science and Technology of Kosovo (Nr.2-5069) for providing him with the computing resources.

  1. Conflict of interest

    Authors declare no conflict of interest.

References

[1] Delamar M., Hitmi R., Pinson J., Savean J.M., Covalent Modification of Carbon Surfaces by Grafting of Functionalized Aryl Radicals Produced from Electrochemical Reduction of Diazonium Salts. J. Am. Chem. Soc., 1992, 114(14), 5883–5884.10.1021/ja00040a074Search in Google Scholar

[2] Pujari S. P., Scheres L., Marcelis A. T. M., Zuilhof H., Covalent Surface Modification of Oxide Surfaces. Angew. Chemie Int. Ed., 2014, 53(25), 6322–6356.10.1002/anie.201306709Search in Google Scholar PubMed

[3] Bélanger D., Pinson J., Electrografting: A Powerful Method for Surface Modification. Chem. Soc. Rev., 2011, 40(7), 3995–4048.10.1039/c0cs00149jSearch in Google Scholar PubMed

[4] Berisha, A., Chehimi M., Pinson J., Podvorica F., Electrode Surface Modification Using Diazonium Salts. Electroanalytical Chemistry. CRC Press, 2015.10.1201/b19196-4Search in Google Scholar

[5] Combellas C., Delamar M., Kanoufi, F., Pinson J., Podvorica F., Spontaneous Grafting of Iron Surfaces by Reduction of Aryldiazonium Salts in Acidic or Neutral Aqueous Solution. Application to the Protection of Iron against Corrosion, 2005.10.1021/cm050339qSearch in Google Scholar

[6] Guo K., Chen X., Freguia S., Donose B. C, Spontaneous Modification of Carbon Surface with Neutral Red from Its Diazonium Salts for Bioelectrochemical Systems. Biosens. Bioelectron., 2013, 47, 184–189.10.1016/j.bios.2013.02.051Search in Google Scholar PubMed

[7] Toupin M., Bélanger D., Spontaneous Functionalization of Carbon Black by Reaction with 4-Nitrophenyldiazonium Cations. Langmuir, 2008, 24(5), 1910–1917.10.1021/la702556nSearch in Google Scholar PubMed

[8] Halili J., Salihu F., Berisha, A., Covalent Attachment of Phenyl and Carboxyphenyl Layers Derived from Diazonium Salts onto Activated Charcoal for the Adsorption of Pesticides. Maced. J. Chem. Chem. Eng., 2018, 37,1.10.20450/mjcce.2018.1442Search in Google Scholar

[9] Berisha, A., Combellas, C., Kanoufi, F., Médard, J., Decorse, P., Mangeney, C., Kherbouche, I., Seydou, M., Maurel, F.; Pinson, J., Alkyl-Modified Gold Surfaces: Characterization of the Au-C Bond. Langmuir, 2018, 34(38), 11264–11271.10.1021/acs.langmuir.8b01584Search in Google Scholar PubMed

[10] Agnès C., Arnault J.C., Omnès F., Jousselme B., Billon M., Bidan G., Mailley P., XPS study of ruthenium trisbipyridine electrografted from diazonium salt derivative on microcrystalline boron doped diamond. Phys. Chem. Chem. Phys., 2009,11, 11647-11654.10.1039/b912468cSearch in Google Scholar PubMed

[11] Raicopol M., Necula L., Ionita M., Pilan L., Electrochemical reduction of aryl diazonium salts: a versatile way for carbon nanotubes functionalisation. Surf. Interface Anal., 44, 1081-1085.10.1002/sia.4830Search in Google Scholar

[12] Stockhausen V., Trippé-Allard G., Quynh N., Ghilane J., Lacroix J-C., Grafting π-Conjugated Oligomers Incorporating 3,4-Ethylenedioxythiophene (EDOT) and Thiophene Units on Surfaces by Diazonium Electroreduction. J. Phys. Chem. C., 2015, 119, 33, 19218-19227.10.1021/acs.jpcc.5b05456Search in Google Scholar

[13] Mangeney C., Qin Z., Dahoumane S.A., Adenier A., Herbst F., Boudou J.-P., Pinson J., Chehimi M.M., Electroless Ultrasonic Functionalization of Diamond Nanoparticles Using Aryl Diazonium Salts. Diam. Relat. Mater., 2008, 17 (11), 1881–1887.10.1016/j.diamond.2008.04.003Search in Google Scholar

[14] Bouriga M., Chehimi M.M., Combellas C., Decorse P., Kanoufi F., Deronzier A., Pinson J., Sensitized Photografting of Diazonium Salts by Visible Light. Chem. Mater., 2013, 25(1), 90–97.10.1021/cm3032994Search in Google Scholar

[15] Quarels R. D., Zhai X., Kuruppu N., Hedlund J.K., Ellsworth A.A., Walker A.V., Garno J. C., Ragains J. R., Application of visible-light photosensitization to form alkyl-radical-derived thin films on gold. Beilstein J. Nanotechnol., 2017, 8, 1863–1877.10.3762/bjnano.8.187Search in Google Scholar PubMed PubMed Central

[16] Mahouche-Chergui S., Gam-Derouich S., Mangeney C., Chehimi M.M., Aryl diazonium salts: a new class of coupling agents for bonding polymers, biomacromolecules and nanoparticles to surfaces. Chem. Soc. Rev., 2011, 40, 4143-4166.10.1039/c0cs00179aSearch in Google Scholar PubMed

[17] Jiang D., Sumpter B., Dai S., How Do Aryl Groups Attach to a Graphene Sheet? J. Phys. Chem. B., 2006, 110(47), 23628–23632.10.1021/jp065980+Search in Google Scholar PubMed

[18] Berisha A., Combellas C., Kanouf, F., Decorse P., Oturan N., Médard J., Seydou M., Maurel F., Pinson J., Some Theoretical and Experimental Insights on the Mechanistic Routes Leading to the Spontaneous Grafting of Gold Surfaces by Diazonium Salts. Langmuir, 2017, 33(35).10.1021/acs.langmuir.7b01371Search in Google Scholar PubMed

[19] Bahr J.L., Tour J.M., Highly Functionalized Carbon Nanotubes Using in Situ Generated Diazonium Compounds. Chem. Mater., 2001, 13, 11, 3823-3824.10.1021/cm0109903Search in Google Scholar

[20] Paulus G.L.C., Wang Q.H., Strano M.S., Covalent Electron Transfer Chemistry of Graphene with Diazonium Salts. Acc. Chem. Res., 2013, 46(1), 160–170.10.1021/ar300119zSearch in Google Scholar PubMed

[21] Flavin K., Chaur M.N., Echegoyen L., Giordani S., Functionalization of Multilayer Fullerenes (Carbon Nano-Onions) Using Diazonium Compounds and “Click” Chemistry. Org. Lett., 2010, 12(4), 840–843.10.1021/ol902939fSearch in Google Scholar PubMed

[22] Lalaoui N., Holzinger M., Le Goff A., Cosnier S., Diazonium Functionalisation of Carbon Nanotubes for Specific Orientation of Multicopper Oxidases: Controlling Electron Entry Points and Oxygen Diffusion to the Enzyme. Chem. - A Eur. J., 2016, 22(30), 10494–10500.10.1002/chem.201601377Search in Google Scholar PubMed

[23] Salice P., Fabris E., Sartorio C., Fenaroli D., Figà V., Casaletto M.P., Cataldo S., Pignataro B., Menna E., An Insight into the Functionalisation of Carbon Nanotubes by Diazonium Chemistry: Towards a Controlled Decoration. Carbon., 2014, 74, 73–82.10.1016/j.carbon.2014.02.084Search in Google Scholar

[24] Schmidt G., Gallon S., Esnouf S., Bourgoin J.P., Chenevier P., Mechanism of the Coupling of Diazonium to Single-Walled Carbon Nanotubes and Its Consequences. Chem. - A Eur. J., 2009, 15(9), 2101–2110.10.1002/chem.200801801Search in Google Scholar PubMed

[25] Bahr J. L., Yang J., Kosynkin V.D., Bronikowski J.M., Smalley E.R., Tour J.M., Functionalization of Carbon Nanotubes by Electrochemical Reduction of Aryl Diazonium Salts: A Bucky Paper Electrode. J. Am. Chem. Soc., 2001, 123(27), 6536–654.10.1021/ja010462sSearch in Google Scholar PubMed

[26] Cohen A.J., Mori-Sánchez P., Yang W., Challenges for Density Functional Theory. Chem. Rev., 2012, 112(1), 289–320.10.1021/cr200107zSearch in Google Scholar PubMed

[27] Jones R. O., Density Functional Theory: Its Origins, Rise to Prominence, and Future. Rev. Mod. Phys., 2015, 87(3), 897–923.10.1103/RevModPhys.87.897Search in Google Scholar

[28] Vanommeslaeghe K., Guvench O., MacKerell A. D., Molecular Mechanics. Curr. Pharm. Des., 2014, 20(20), 3281–3292.10.2174/13816128113199990600Search in Google Scholar PubMed PubMed Central

[29] Ding N., Chen X., Wu C.M.L., Interactions between Polybrominated Diphenyl Ethers and Graphene Surface: A DFT and MD Investigation. Environ. Sci. Nano, 2014.10.1039/C3EN00037KSearch in Google Scholar

[30] Perdew J.P., Burke K., Ernzerhof M., Generalized Gradient Approximation Made Simple. Phys. Rev. Lett., 1996, 77(18), 3865–3868.10.1103/PhysRevLett.77.3865Search in Google Scholar PubMed

[31] Seydou M., Lassoued K., Tielens F., Maurel F., Raouafi F., Diawara B., A DFT-D Study of Hydrogen Adsorption on Functionalized Graphene. RSC Adv., 2015, 5(19), 14400–14406.10.1039/C4RA15665JSearch in Google Scholar

[32] Mehmeti V. V., Berisha A.R., Corrosion Study of Mild Steel in Aqueous Sulfuric Acid Solution Using 4-Methyl-4h-1,2,4-Triazole-3-Thiol and 2-Mercaptonicotinic Acid-an Experimental and Theoretical Study. Front Chem., 2017, 5, 61.10.3389/fchem.2017.00061Search in Google Scholar PubMed PubMed Central

[33] Klamt A., The COSMO and COSMO-RS Solvation Models. Wiley Interdiscip. Rev. Comput. Mol. Sci., 2018, 8(1), e1338.10.1002/wcms.1338Search in Google Scholar

[34] Govind N., Petersen M., Fitzgerald G., King-Smith D., Andzelm J.A., Generalized Synchronous Transit Method for Transition State Location. Comput. Mater. Sci., 2003, 28 (2), 250–258.10.1016/S0927-0256(03)00111-3Search in Google Scholar

[35] Lu T., Chen F., Multiwfn: A Multifunctional Wavefunction Analyzer. J. Comput. Chem., 2012, 33(5), 580–592.10.1002/jcc.22885Search in Google Scholar PubMed

[36] Humphrey W., Dalke A., Schulten K., VMD: Visual Molecular Dynamics. J. Mol. Graph. 1996, 14 (1), 33–38.10.1016/0263-7855(96)00018-5Search in Google Scholar PubMed

[37] Sun H., Jin Z., Yang C., Akkermans R.L.C., Robertson S.H., Spenley N.A., Miller S., Todd S.M., COMPASS II: Extended Coverage for Polymer and Drug-like Molecule Databases. J. Mol. Model., 2016, 22(2), 47.10.1007/s00894-016-2909-0Search in Google Scholar PubMed

[38] Hobza P., Řezáč J., Introduction: Noncovalent Interactions. Chem. Rev., 2016, 116(9), 4911–4912.10.1021/acs.chemrev.6b00247Search in Google Scholar PubMed

[39] Sinnokrot M.O., Valeev F.E., Sherrill C. D., Estimates of the Ab Initio Limit for π−π Interactions: The Benzene Dimer. J. Am. Chem. Soc., 2002, 124(36), 10887–10893.10.1021/ja025896hSearch in Google Scholar PubMed

[40] Berisha A., Interactions between the Aryldiazonium Cations and Graphene Oxide: A DFT Study. Journal of Chemistry, 2019, Article ID 512607.10.1155/2019/5126071Search in Google Scholar

Received: 2018-12-03
Accepted: 2019-03-22
Published Online: 2019-09-25

© 2019 Avni Berisha, published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 Public License.

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