IUPAC definition: Graphene is a single carbon layer of the graphite structure, describing its nature by analogy to a polycyclic aromatic hydrocarbon of quasi infinite size.

Graphene, as others hydrocarbons, can undergo many reactionsin order to afford necessary flexibility to adapt it into specific performances.

“Organic chemistry can be defined as the the study of the structure, properties, reactions, and preparation of carbon-containing compounds …”

Karla S. Feu Baran Group Meeting10-06-18Graphene Chemistry

Topics included in this group meeting: Graphene background, synthesis, application as catalysts, characterization and perspectives.

Not covered in this group meeting: Applications in photocatalysis, sensors,supercapacitors, drug delivery and Full cells/ORR.

Graphite oxide preparedby Schafhaeutl, Brodie,

Staudenmaier, Hummersand others

Boehm and co-workersprepare reduced graphene

oxide (rGO) by the chemical and thermal reduction of

graphite oxide

Morgan and Somorjaiobtain LEED patternsproduced by small-molecule adsorption

onto Pt(100)

May interprets the datacollect by Morgan and

Somorjai as the presenceof monolayer of graphite

on the Pt surface

Blakely and co-workesprepare monolayer

graphite by segregationcarbon on the surface of

Ni(100); severalsubsequent reports follow

van Bommel andco-workers prepare

monolayer graphite bysubliming silicon from

silicon cabide

Ruoff and co-workersmicromechanically

exfoliate graphite into thin lamellae

comprised of multiplelayers of graphene

Boehm and co-workersrecommend that the term

“graphene” be used todescribe single layers of

graphite-like carbon

IUPAC formalizes the definition of graphene: “The term graphene should

be used only when the reactions,structural relations or other properties

of individual layers are discussed”

Geim and co-workers prepare graphene via

micromechanical exfoliation; numerous

reports follow

19621840-1958 1968

19691970 1975

1986 1997 1999 2004

Timeline of selected events in the history of the preparation, isolation and characterization of graphene.

2010

Why study graphene and its derivatives?

Dreyer et al. ACIE. 2010, 49, 9336.

Graphene is an exciting and unique material which shows peculiar electronic, optical, mechanical and chemical properties, among others, which have found application in numerous scientific and technological areas.

Family of Graphene:

Synthetic Organic Chemistry? Graphene?Can we make organic synthesis on two-dimensional planes?

OOH

HO O HOH

O

OO

OOH

O

O OH

O

HOO

OHOH

OHHO

O

O OO

OHO

O

Karla S. FeuBaran Group Meeting

10-06-18Graphene ChemistryOverview of Principals Methods of Synthesis for Graphene-based Materials:

Hummers method (1958)Other methods: Brodie, Staudenmaier, Hofman and Tour.Advantages: Most Used method, Large scale production, Medium quality GM.Disadvantages: Impurities and defects, GM of low electrical conductivity, Large production of liquid wastes.

Advantages: Low cost, Large scale production, Green synthesis method, easy doping.Disadvantages: Medium quality graphene.Advantages: High quality graphene

Disadvantages: Time consuming, Low production.

Advantages: High quality graphene, absence of impurities.Disadvantages: Low production.

Mechanical exfoliation

Chemical Oxidation Chemical vapor deposition (CVD)

Pyrolysis of precursors

Synthesis of Graphene and its derivatives

Graphene oxide (GO)

Hummers method and subsequent sonication

Proposed structure of GO based on the Lerf Klinowski model

Graphene layers without functionalization are insoluble andinfusible, which limits their application capabilities.

The essential purpose of graphene derivatisation is to tailorits physical and chemical properties.The synthesis of graphenederivatives can be divided in two major process: a) bottom-up andb) top-down.

Wang et al. Nat. Rev. Chem. 2017, 2, 00100.Navalon et al. Chem. Rev. 2014, 114, 6179.

GO is currently the principal precursor used for the synthesis of graphene materials. Morover, GO itself has attracted considerable attention due the oxygen functional groups on its surfaces.GO has attracted considerable attention as potential material for use in photovotaic cells, capacitors, sensor and catalysis.

Karla S. FeuBaran Group Meeting

10-06-18Graphene Chemistry

Synthesis of Graphene-based Materials:Graphene (G) as starting material:

N2

HO

HOF

FF

F

FFF

R

BrMgR

G

a)

b)

+ e--N2

N2

-N2

Fluorographene (FG) as starting material:

FG

O OH

GO - simplified structureOHO

GO as starting material:

Fe

O

SOCl2 orDCC, DMAP

X RH

X= O, NH

Fe

1. (CF3C

O)2O,acidic alumina

O OH

GO

O OH O OH

OHO

1. NaBH4 or2. KOH/ H2O or3. N2H4

ArArN2X

2.

O OH

OHHO

O OH

OH

OHO

O OH

OHN3

NaN3

N NN

R RO XR

OHO

O NHR

OO R

O

NHR

RNH2

RNCO

Navalon et al. Chem. Rev. 2014, 114, 6179.

Ma et. al. ACS Catal. 2016, 6, 6948.

N

N N NN

O

COOH SO3H

NR2

O

O

O

OO

O OH

OH

OHOHO HO

Active defects sites

Quinone-diolredox site

π-System Pyridine

Amine Solid basesSolid acids

Zigzag edge

Arm

chai

r edg

e

Diagram of Active Sites of Graphene - Based Nanomaterials

Karla S. FeuBaran Group Meeting

10-06-18Graphene Chemistry

GO as catalyst

NO2

NC CN

One-potHenry-Michael

87% yield6 x recycled

Zhang et al. ACS Appl. Mat. Interfaces 2015, 7, 1662.

R

0-92% yield15 examples5 x recycled

Gao et al. ACIE 2016, 55, 3124.C-H

coupling

Synthesis of thioethers

Sulfoxidation

Alkylation ofArenes

Iodination

C-Ccoupling

Ar

O

O

C-Ncoupling

NR

R

I O

R

Ior

R1

R2

SO

SO O

Ar SR

CH3

Zhang et al. ChemCatChem 2018, 10, 376.

Goncalves et al. Chem. Commun 2014, 50, 7673.

Hu et al. JACS 2015, 137, 14473.

Majumdar et al. ACS Sustain. Chem. Eng. 2017, 5, 9286.

Basu et al. RSC Adv. 2013, 3, 22130.

Fan et al. Asian JOC 2018, 7, 355.

40% yield35-92% yield29 examples

68-82% yield20 examples5 x recycled

62-99% yield (mono)20, 6 examples

81% yield4 x recycled

Ar1 Ar2

R MeAr1 Ar2

R

57-99% yield15 examples

82-95% yield2 examples

a-ketoamides

Application as catalysts: GO

O

OH

HO O H

OH

O

O

O

OOH

O

O OH

O

HOO

OHOH

OHHO

O

O OO

OHO

O

Graphene oxide (GO)

=

O

O OH

OH

O OH

OHO

GOAr1

R1

Ar1 Me

R1HO GO

Ar2-H

Ar1 Me

R1HO GO

Ar2 H

Ar1 Me

R1 O GO

Ar2 H

Ar1 Ar2

R1 Me

R

OH

OMe

OMe

R OMe

OMe

GO, air

CHCl3, 100°CR = HR = Me

R = H, 82%R = Me, 95%

Hu et al. JACS 2015, 137, 14473.

GO (200 wt%), air

CHCl3, 100°CAr1

R1

Ar1

R1

Ar2

Me

Alkylation of Arenes

viaO Ar2

Ar1

R H

34-80% yield21 examples

Proposed mechanism

Karla S. FeuBaran Group Meeting

10-06-18Graphene Chemistry

GO shell GO shell

HR

H

Proposed mechanism

R R

RRadicalcoupling

Fan et al. Asian JOC 2018, 7, 355.

RH

R

RGO (40mg)

CH3CN, 100°C,argon, 12h

C-C coupling

GO shell

GO shell

Proposed mechanism

I

I I

I H

Ar

H

Ar

IH

Ar

I

Ar

I IH

HIAromatization

SET e

Iodination

Initiation

Radicaladdition

Zhang et al. ChemCatChem 2018, 10, 376.

H

orAr Ar

OI

R

I

Ar

GO(20mg), I2 (1.1 equiv)CH3NO2 (0.7 mL)

120°C, 1h, air

orAr

OI

R

Application as catalysts: rGO

OO

H

HrGO

rGO

rGO

H2O2

OH

H2O + O2

k2

k3By-products

OH333K

rGO, MeCNH2O2 18% yield

5 x recycled

Proposed mechanism

Yang et al. Energy Environ. Sci. 2013, 6, 793.

Karla S. FeuBaran Group Meeting

10-06-18Graphene ChemistryCharacterization Techniques:

*Atomic emission (AES), *absorption spectroscopy (AAS) or *inductivelycoupled plasma mass spectrometry (ICP -MS): Presence of metal impurities.*Combustion elemental analysis: composition*TPD: thermal stability

Analytical Techniques: Microscopy (M): morphology and single layer confirmation

*Transmission electron M (TEM)*Scanning electron M (SEM)*Atomic force M (AFM)*Elemental mapping (Energy dispersive X-ray)

Spectroscopy:functional groups and metal oxidation date*Raman*FT-IR*XPS*UV-Vis*Solid-state NMR

*Thermogravimetry*Thermodesorption

Thermal Analysis:interaction with oxidizing reducing agents

Textural characterizationBET: surface area of powders

XRD: crystallinity and stacking

Raman UV-vis

SS-NMR Adsorption isotherm: BET Thermal analysis: ATG

XPS

PXRD

Karla S. FeuBaran Group Meeting

10-06-18Graphene Chemistry

TEM Energy dispersive X-ray: EDXSEM AFM

Others Appllications and Perspectives:

# Lithium ion battery

# Solar cells

# Supercapacitores

#Bio applications

# Sensors

# Water desalination

Karla S. FeuBaran Group Meeting

10-06-18Graphene Chemistry Applications : Biosensors

Perspectives

Park et al. Langmuir 2014, 30, 12587.

Schematic of the Desorption Mechanism of the Probe DNA adsorved on GO, driven by the addition of (A) cDNA and (B) Non-cDNA

# More complex derivatives of graphene;

# The research should also focus on well defined graphene;

# A more intensive collaboration between synthetic chemists, polymer chemists and biologists;

# In the field of catalysis, the exploration in the unchartered territory of enantioselective transformations;

# The potencial of the graphene-based materials are huge and still in the begin.