Electrochemical and structural investigation of the interactions between naphthalene diimides and metal cations

Article abstract of DOI:10.1039/c7dt02067h

The effects of Li⁺ and Mg²⁺ on the electrochemical behaviour and photoreduction of N,N′-bis(2,6-diisopropylphenyl)naphthalene diimide (Dipp₂NDI) have been investigated using cyclic voltammetry and UV-vis spectroscopy. Strong cation-anion interactions between Li⁺ or Mg²⁺ and [Dipp₂NDI]^2- result in solvent-dependent anodic shifts of the NDI^-/2- redox couple. In organic solvents of moderate dielectric constant and donor ability, the two, one-electron redox processes typically observed for Dipp₂NDI merge into a single, two-electron process. This strong metal cation effect has been leveraged for the photoreduction of Dipp₂NDI to [Dipp₂NDI]^2-via a disproportionation process. Chemical reduction of Dipp₂NDI with iPrMgCl has allowed the isolation of Mg²⁺ complexes of [Dipp₂NDI]^2-. Single crystal X-ray diffraction was used to determine the structure of a dimeric complex, [(Dipp₂NDI)Mg₂(THF)₃]₂, that features strong coordination of Mg²⁺ by the oxygen atoms of the reduced NDI.

Full text of DOI:10.1039/c7dt02067h

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: B. R. Reiner, B. M.
Foxman and C. R. Wade, Dalton Trans., 2017, DOI: 10.1039/C7DT02067H.
Volume 45 Number
1
7
January 2016 Pages 1–398
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
An international journal of inorganic chemistry
www.rsc.org/dalton
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
rsc.li/dalton

Page 1 of 10
Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
View Article Online
DOI: 10.1039/C7DT02067H
Journal Name
ARTICLE
Electrochemical and Structural Investigation of the Interactions
between Naphthalene Diimides and Metal Cations
a
a
a
Benjamin R. Reiner, Bruce M. Foxman, and Casey R. Wade *
Received 00th January 20xx,
Accepted 00th January 20xx
The effects of the Li+ and Mg2+ on the electrochemical behaviour and photoreduction of N,N’-bis(2,6-
DOI: 10.1039/x0xx00000x
diisopropylphenyl)naphthalene diimide (Dipp
spectroscopy. Strong cation-anion interactions between Li or Mg and [Dipp
shifts of the NDI·−/2− redox couple. In organic solvents of moderate dielectric constant and donor ability, the two, one-
electron redox processes typically observed for Dipp NDI merge into a single, two-electron process. This strong metal cation
effect has been leveraged for the photoreduction of Dipp
reduction of Dipp
2
NDI) have been investigated using cyclic voltammetry and UV-vis
+
2+
NDI]2− result in solvent-dependent anodic
2
www.rsc.org/
2
NDI to [Dipp
2
NDI]2− via a disproportionation process. Chemical
2
NDI with iPrMgCl has allowed the isolation of Mg2+ complexes of [Dipp
2−
2
2
NDI] . Single crystal X-ray
diffraction was used to determine the structure of a dimeric complex, [(Dipp
coordination of Mg2+ by the oxygen atoms of the reduced NDI.
2
NDI)Mg
2
(THF) ] , that features strong
3
2
+
2+
were observed for the NDI-based polymer, Li and Mg had no
effect on the redox behaviour of the NDI monomer in DMSO
solution.
Introduction
The ability of redox-inactive metal cations to promote
electron transfer has recently attracted considerable
RDIs are also well known to undergo photoreduction to
·
−
radical anion species (RDI ) in the presence of electron donors.
This behaviour has been exploited for the study of
1
attention. Moreover, mechanistic studies on metal ion-
coupled electron transfer (MCET), defined in analogy to proton-
coupled electron transfer (PCET), have been carried out with
both organic and inorganic electron acceptors. In general,
interactions between an electron acceptor and metal cation
result in a positive shift in the reduction potential of the
acceptor. This effect has been rigorously investigated for
10
photoinduced charge separation and photooxidation of
11
DNA. Visible light-absorbing perylene diimides (PDIs) have
also been investigated as photosensitizers for catalytic water
2
12
13
14
splitting, CO
2
reduction, and reduction of aryl halides.
Despite the myriad of photochemical studies involving
·
−
formation of RDI species, photogeneration of doubly reduced
3
quinones and other carbonyl-containing molecules and was
2
−
15
RDI species has rarely been reported. Consequently, new
recently exploited to facilitate photoinduced charge
2−
strategies for photochemical generation of RDI species may
better position RDIs for use in multi-electron photocatalysis.16
Considering the paucity of previous studies and implications
toward energy storage and multi-electron transformations, we
decided to more thoroughly investigate the interaction of
redox-inactive metal cations with RDIs. Herein we report that
4
accumulation
and increase the energy density of
electrochemical energy storage (EES) materials.5
6
Rylene diimides (RDIs) have been widely studied in EES and
light harvesting applications owing to their modest reduction
7
potentials, tunable light absorption, and chemical stability. RDIs
typically exhibit two reversible one-electron reductions that are
reminiscent of those observed for quinones. Despite this
similarity, investigations into the influence of metal cations on
the electro- and photochemical behaviour of RDIs remain
+
2+
Li and Mg prompt the appearance of two-electron redox
processes for N,N’-bis(2,6-diisopropylphenyl)naphthalene
diimide (Dipp NDI) in organic solvents of moderate dielectric
2
constant and donor ability. Electrochemical titrations show that
this effect is driven by strong interactions between the doubly
8
+
scarce. Dichtel and coworkers recently reported that Li and
2+
Mg induce anodic shifts of the second reduction potential of
naphthalene diimides (NDI) incorporated in a polymer thin
2
−
+
reduced diimide ([Dipp
2
NDI] ) and metal cations. Moreover, Li
2+
and Mg have been found to facilitate efficient photoreduction
9
2+
film. The effect was especially pronounced with Mg for which
the two one-electron redox processes were observed to merge
into a single two-electron process. Although dramatic effects
2−
of Dipp
electron donor by inducing disproportionation of [Dipp
Finally, chemical reduction of Dipp NDI has led to X-ray
structural characterization of a dimeric Mg complex of
2 2
NDI to [Dipp NDI] in the presence of a sacrificial
·
−
2
NDI] .
2
2+
2−
2+
[
2
Dipp NDI] . The complex features strong coordination of Mg
a.Department of Chemistry, Brandeis University 415 South St., Waltham, MA, USA.
E-mail: cwade@brandeis.edu
by the oxygen atoms of the reduced NDI and is the first
†
Electronic Supplementary Information (ESI) available: Experimental details,
electrochemical, PXRD, analytical data, and X-ray structure determination. CCDC
539171. See DOI: 10.1039/x0xx00000x
2−
structurally characterized example of an NDI species.
1
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Page 2 of 10
ARTICLE
Journal Name
no effect on the NDI·−/2− reduction wave in DMSO solution (ε
=
View Article Online
r
Results and Discussion
DOI: 10.1039/C7DT02067H
4
6.7).
Electrochemistry
2
Changes in the electrochemical behaviour of Dipp NDI upon
addition of Na , Li+ or Mg were monitored using cyclic
voltammetry (CV). All experiments were carried out in
anhydrous organic solvents, namely acetonitrile (MeCN),
tetrahydrofuran (THF), N,N-dimethylformamide (DMF), or
+
2+
dimethylsulfoxide (DMSO) with 0.1 M TBAPF
6
as the supporting
−
−
electrolyte. Anhydrous NaOTf (OTf = CF
3
SO
3
), Li(PF
6
), and
−
−
2 2 2 3 2 2
Mg(NTf ) (NTf = (CF SO ) N ) were used as sources of the
respective metal cations and were chosen for their solubility as
well as the weakly coordinating nature of the counter anions.
The cathodic sweeps of the voltammograms measured upon
titration of Dipp
2 6 2 2
NDI with Li(PF ) and Mg(NTf ) are shown in
Fig. 1. The complete set of voltammograms can be found in the
ESI.† In MeCN solution, Dipp
2
NDI (1 mM) exhibits two reversible
reductions at E1/2 = −0.92 (NDI0/·−) and −1.38 V (NDI ) versus
·−/2−
0/+
6
Fc (Fig. S1, ESI†). Titration with LiPF (0-150 equiv.) produces
a progressive anodic shift of the NDI·
−/2−
reduction wave (Epc
=
−
1.45 V) to the point that it merges with the NDI0/·− wave to give
a single two-electron reduction at Epc = −0.83 V. (Fig. 1A). The
NDI0 reduction wave (Epc = −0.94 V) remains unchanged in the
/·−
+
presence of up to 10 equiv. of Li . In contrast, the addition of
2 2 2
one equiv. of Mg(NTf ) to an MeCN solution of Dipp NDI results
in the appearance of a single two-electron reduction wave
NDI0 ) at Epc = −0.97 V (Fig. 1B). The presence of up to 100
/2−
(
·
−/2−
equiv. of NaOTf resulted in only a slight shift of the NDI
reduction wave (ΔEpc = 0.03 V) in MeCN (Fig. S2 ESI†). In THF
0/·−
·−/2−
solution, reversible NDI
observed at E1/2 = −1.04 and −1.69 V, respectively (Fig. S3 ESI†).
Titration with up to 10 equiv. of LiPF or Mg(NTf results in
and NDI
redox couples are
6
2 2
)
large anodic shifts of the NDI·−/2− couple, but the effects are
quite different from those observed in MeCN solution. A single,
two-electron reduction appears at Epc = −1.17 V (Fig. 1C) after
Fig. 1 Cathodic sweeps of the cyclic voltammograms of Dipp
DMSO solution upon titration with up to 150 equiv. of LiPF
2
NDI in MeCN, THF, DMF, or
6
or Mg(NTf . Addition of 0
2 2
)
addition of only 6 equiv. of LiPF
of Mg(NTf
waves at Epc = −1.14 and −1.28 V, respectively (Fig. 1D).
6
. Titration with up to 10 equiv. to 10 equiv. of the metal salts is shown in red to blue colour transitions; 10 to 150 equiv.
results in overlapping NDI0/·− and NDI·−/2− reduction is shown in blue to green colour transitions. All measurements were performed with 1
mM Dipp NDI and 0.1 M TBAPF supporting electrolyte at a scan rate of 100 mV/s. The
complete set of voltammograms can be found in Figs. S1-S5 in the ESI.†
2 2
)
2
6
+
2+
The effects of Li and Mg on the redox properties of
Dipp NDI are greatly diminished in DMSO and DMF solution. In
DMF, the NDI
shifts upon titration with up to 100 equiv. of Li or Mg (Fig.
2
+
2+
·
−/2−
While Li and Mg prompt similar changes in the NDI redox
waves, there are clear differences in the magnitude of their
reduction wave experiences only small anodic
+
2+
+
·−/2−
effects. Li induces a larger shift of the NDI
reduction wave
1
1
E,F), and almost no shift is observed in DMSO solution (Fig.
2+
0/·−
·−/2−
than Mg in THF, DMF, and DMSO solution. This situation is
reversed in MeCN solution where only one equiv. of Mg2+ is
necessary to observe the appearance of a single two-electron
G,H). The NDI
and NDI
redox processes show
reversibility in all solvents. However, changes in peak shape of
some of the anodic waves in THF and MeCN suggest adsorption
2+
3d
reduction wave. Mg might be expected to have a greater
effect on the NDI redox processes in all of the solvents tested
owing to its increased charge and Lewis acidity. However, these
same considerations result in larger desolvation energies for
of reduced species on the electrode surface.
From the CV titration data, it is clear that small, charge
dense cations influence the redox behaviour of NDIs in solution.
The magnitude of this influence is highly dependent on the
solvent medium and can be correlated with solvent dielectric
2+
Mg , lessening its interaction with the reduced NDI species
17
(vide infra).
r
constant (ε ) and donor properties. The most pronounced shifts
·
−/2−
Previous electrochemical studies with p-quinones have
in the NDI
the lowest dielectric constant in the series (ε
more weakly coordinating than DMF or DMSO. On the other
reduction waves are observed in THF, which has
+
2+
indicated strong binding of Li or Mg to quinone radical
r
= 7.52) and is
3d, 18
anions.
However, in the case of Dipp
NDI redox couple remains largely unaffected by the presence
of moderate amounts of Li or Mg suggests that [Dipp NDI]
2
2
NDI, the fact that the
0/·−
+
2+
hand, up to 100 equiv. of Li or 50 equiv. of Mg have almost
+
2+
·−
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

∆
퐸푝푐
=
log(훽) − 푞
log
Page 3 of 10
Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Journal Name
ARTICLE
does not interact strongly with these metal cations. Instead, the almost 10 orders of magnitude, reflect the profound influence
View Article Online
large anodic shifts of the NDI·−/2− reduction wave indicate that of solvent on cation complexation. Moreover, the formation
DOI: 10.1039/C7DT02067H
2
−
+
the dominant interactions occur between [Dipp
metal cations.
2
NDI] and the constant for complexation of Li in DMF is two orders of
2+
magnitude greater than for Mg in the same solvent. Again, this
is consistent with the stronger solvent-cation interactions that
must be overcome for complexation of [Dipp
17 Although Eq. 1 can also provide information about the
0.05916
0.05916
푧
2−
2+
([푀푛+])
2
NDI] with Mg .
푧
Equation 1. Epc = Shift in peak cathodic peak potential; z = Number of electrons stoichiometry of complexation (q), changes in diffusion
transferred; = formation constant; q = Stoichiometry of complexation. See ESI for
additional details.†
properties of the ion-paired species have hampered the
extraction of meaningful data from this analysis.
Fig. 2 Plots of ΔEpc versus log[Mn+] for titrations with Li in MeCN (A), DMF (B), or DMSO
+
(
D) and Mg2+ in DMF (C).
Table 1. Shifts in cathodic peak potential (ΔEpc) of the NDI·−/2− redox couple upon addition
+
2+
of Li or Mg in different solvents and formation constants log().
Cation
Li
Li
Mg
Li
Mg
Li
Mg
Li
Mg
Equiv.
10
150
10
Solvent
MeCN
MeCN
MeCN
THF
Epc(NDI·−/2−)/V
0.24
log()
10.5
10.5
N.D.
N.D.
N.D.
4.7
0.62
0.49
10
10
0.68
0.48
THF
100
50
DMF
DMF
0.14
0.07
2.7
100
50
DMSO
DMSO
0.06
N/A
1.8
N.D.
Formation constants for complexation of [Dipp
2
NDI]2− with
+
2+
Li in MeCN, DMF, and DMSO and with Mg in DMF were
19
estimated using Eq. 1. The rapid appearance of two-electron
Fig. 3 (a) UV-vis difference spectra measured for a THF solution of Dipp
2
NDI (8.9 µM),
reduction processes for the titrations in THF and with Mg2+ in LiPF
(180 µM), and Et N (0.17 M) upon irradiation at 365 nm for 0 – 480 s
6
3
(
green to blue to red colour transitions). The spectrum measured at t = 0 s served as a
baseline. Also shown are images of the reaction vessel illustrating qualitative colour
changes during the experiment. (b) UV-vis spectra measured on a THF solution of
MeCN preclude analysis of those data. Moreover, the analyses
were carried out using the cathodic peak potentials (Epc) rather
than half-wave potentials (E1/2) owing to changes in peak shape
2 3
Dipp NDI (8.9 µM), metal salt (180 µM), and Et N (0.17 M). Samples were irradiated at
of the anodic waves in some of the titrations, possibly due to 365 nm for 600 s. Additional details can be found in the text and ESI.†
adsorption of the reduced species on the surface of the
3d
electrode. Fig. 2 shows good linear correlations between the
·
−/2−
shifts in potential of the NDI
reduction waves (ΔEpc) and
n+
log[M ]. From the least squares fits of this data and Eq. 1,
formation constants (logβ) of 10.5, 4.7, and 1.8 were calculated
+
for Li complexation in MeCN, DMF, and DMSO, respectively.
The large differences in these formation constants, which span
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Page 4 of 10
ARTICLE
Journal Name
2
NDI, we decided to
2 2
Scheme 1. Proposed mechanism for photoreduction of Dipp NDI to [Dipp
NDI]2− in the
presence of Li or Mg (Mn+).
the electrochemical behavior of Dipp
View Article Online
DOI: 10.1039/C7DT02067H
+
2+
2
explore the chemical reduction of Dipp NDI in hopes of
elucidating the structures of the complexes formed between
Photoreduction
2−
[
2
Dipp NDI] and these cations.
The electrochemical titration data show that in MeCN or
+
2+
THF solution, Li and Mg facilitate two-electron reduction of
NDI] − at similar or slightly less negative
2
Dipp
2
NDI to [Dipp
potentials than the unperturbed NDI
prompted us to consider that [Dipp NDI] might be accessed by
2
photoreduction in the presence of Li or Mg and a suitable
sacrificial electron donor. The photoreduction of NDIs to
2
0/·−
redox couple. This
2−
+
2+
·
−
generate [NDI] is quite common, but examples of
2−
15b
photochemical generation of [NDI] species are rare.
A THF solution of Dipp NDI (8.9 µM), LiPF (180 µM), and
N (0.17 M) was irradiated with a UV lamp array (365 nm) and
product generation was monitored by UV-vis spectroscopy (Fig.
a). Before irradiation, the UV-Vis spectrum exhibits π–π*
transitions corresponding to Dipp NDI at λmax = 359 and 379 nm.
2
6
2
Scheme 2. Synthesis of Mg complexes of [Dipp .
NDI]2−
Et
3
As a result, we found that reaction of Dipp
2
NDI with
3
isopropyl magnesium chloride (iPrMgCl, 5 equiv.) in THF
2
2−
solution generates a Mg complex of [Dipp
microcrystalline solid ( , Scheme 2). The isolated solid is only
2
sparingly soluble in polar aprotic solvents such as THF, CH Cl ,
MeCN, DMSO, and DMF. This poor solubility has precluded
characterization by NMR spectroscopy. However, the UV-Vis
2
NDI] as a red
During the first 30 s of irradiation, these bands decrease in
intensity with concomitant emergence of absorbances
1
2
·
−
consistent with the formation of [Dipp
2
NDI] at λmax = 474, 690,
NDI] absorption bands
20
·−
and 772 nm. After 30 s the [Dipp
2
decrease steadily in intensity as new bands diagnostic of
absorption spectrum of
1 in THF displays absorption bands in
2
−
[
Dipp
2
NDI] appear at λmax = 413, 550, and 598 nm. The
NDI]2− increases up to 480 s at which
the visible region (λmax = 534, 590 nm) that are characteristic of
concentration of [Dipp
2
2
−
20
NDI (Fig. S10, ESI†). Moreover, the ATR-IR spectrum features
point it is the dominant species in solution. The solution
undergoes noticeable colour changes from nearly colourless
−
1
a carbonyl stretching band at 1608 cm , which is redshifted
from the carbonyl band observed for the neutral Dipp NDI and
consistent with data reported for other NDI species (Fig. S11,
ESI†). The compound is highly air and moisture sensitive in
solution but relatively robust in the solid state, maintaining its
characteristic red colour for several hours under ambient
conditions. Elemental and thermogravimetric analysis data are
2
·
−
2−
(
NDI) to brown (NDI ) to red (NDI ) as the dominant species
2−
present change over the course of the experiment (Fig. 3a).
23
Photolysis experiments carried out with Mg(NTf
2
2
)
2
−
(180 µM) in
place of LiPF
6
also led to formation of [Dipp
2
NDI] via a similar
·
−
2
evolution of major species. However, [Dipp NDI] was observed
as the major photoproduct in the absence of any metal cation
additive as well as in the presence of NaOTf (Fig. 3b). In line with
the electrochemical titration data, photoreductions conducted
in MeCN showed similar results to those in THF while irradiation
in DMF resulted in formation of [Dipp
2
NDI]·− as the major
product (Fig. S6 – S8, ESI†). The rapid appearance of
consistent
Dipp NDI)(MgCl)
along with structural considerations (vide infra) have led us to
formulate the tentative structure of shown in Scheme 2.
Importantly, reaction of with excess MeOH results in clean
regeneration of Dipp NDI, indicating that the chemical
with
an
empirical
formula
of
(
2
2
(THF)
4
(Fig. S12, ESI†). This analytical data
1
1
2
[
Dipp
supports
disproportionation of photogenerated [Dipp
2
NDI]·− followed by gradual formation of [Dipp
2
NDI]
2−
reduction does not lead to degradation or functionalization of
the NDI molecule (Fig. S13, ESI†).
2+
a
mechanism in which Li+ and Mg
drive
NDI] rather than
·
−
2
A small number of single crystals were obtained when the
direct two-electron reduction (Scheme 1). This mechanism is
supported by the ready disproportionation of chemically-
reaction of Dipp
2
NDI with iPrMgCl was carried out under dilute
conditions. X-ray diffraction analysis revealed formation of the
·
−
generated [Dipp
2
NDI] upon addition of LiPF
6
or Mg(NTf
2
)
2
(Fig.
centrosymmetric dimer
2
via coordination of adjacent oxygen
+
S9, ESI†). Similar experiments performed with Na did not show
2−
2+
atoms of [Dipp
2
NDI] to two Mg ions (Fig. 4). The structure
any evidence of disproportionation.
also contains highly disordered solvent molecules, presumably
THF, that could not be successfully modelled and their
contribution to the structure factors was removed using the
SQUEEZE routine in PLATON (see ESI†). The coordinated THF
Chemical reduction
Despite extensive study of the photo- and electrochemical
properties of rylene diimides, structurally characterized
examples of reduced radical anion and dianion species remain
2−
2
molecules and portions of the [Dipp NDI] groups are also
severely disordered, precluding detailed analysis of some of the
bond distances and angles. The coordination geometry of the
2
1
rare. Recently, Würthner and coworkers reported the
structure of the sodium salt of a perylene diimide (PDI) dianion
with cyano and chloro substituents in the perylene core.22 The
structure features a two dimensional network assembled via
coordination of the oxygen atoms and nitrile substituents of the
Mg centers of
pyramidal (τ = 0.44) with THF molecules occupying three of the
coordination sites. The Mg1−O4 (1.961(3) Å) and Mg1−O7
2 are best described as distorted square
5
(1.964(4) Å) bond distances are slightly longer than the Mg−OAr
+
+
2+
PDI dianion to the Na ions. Given the effects of Li and Mg on
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 10
Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Journal Name
ARTICLE
distances (1.879−1.923 Å) observed in five-coordinate aryloxide structure of NDI2− should be favoured over the anti form owing
View Article Online
DOI: 10.1039/C7DT02067H
complexes of the form Mg(OAr)
OC (CHMe −2,6; OC Cl −2,4,6; OC
2
(THF)
(CF
3
(OAr
=
to a greater preservation of aromaticity in the Kekulé structure
4
27
6
H
3
2
)
2
6
H
2
3
6
H
2
3
)
3
−2,4,6),2 but of the former. This consideration prompted us to use DFT
shorter than those typically found for κ-O coordination of calculations to determine the relative stability of syn and anti
2
5
neutral amide ligands (2.045−2.067 Å). These comparisons isomers of a protonated model complex, H
2
[Dipp
NDI] exhibits a donor ability intermediate ESI†). The single point energy of the syn isomer after geometry
between aryloxides and amides, although steric factors could optimization was found to be 14 kJ/mol lower than that of the
2
NDI] (Fig. S15,
2−
suggest that [Dipp
2
2−
also play a role in bond lengthening. The C−O and C−C bonds anti isomer. Thus, [Dipp
2
NDI] exhibits a slight thermodynamic
within the imide groups are consistent with the presence of the preference for syn coordination that may help direct the
2−
2
syn resonance form of [Dipp NDI] (Scheme 3). Specifically, the formation of 2.
C13−C35 (1.396(6) Å) and C32−C50 (1.393(7) Å) bond lengths
suggest increased double bond character compared to the
C30−C37 (1.439(12) Å) and C26−C27 (1.440(14) Å) distances. As
expected, the analogous C−C distances observed in solid state
2
structures of Dipp NDI are slightly longer and fall in the range
26
1
.472−1.491 Å.
2
Scheme 3. Syn and anti resonance structures of [R .
NDI]2−
Conclusions
+
In summary, cyclic voltammetry studies show that Li and
Mg2+ can induce large anodic shifts of NDI redox processes in
solution, even to the extent that two-electron reduction is
observed at similar or slightly less negative potentials than the
0/·−
unperturbed NDI redox couple. This effect mainly originates
from strong interactions between the metal cations and NDI2−
while interactions with the neutral (NDI) and radical anion
·
−
(
NDI ) species appear to play a less significant role. The strength
of metal cation binding is highly solvent dependent, and the
effects subside with increasing solvent dielectric constant and
donor ability. Although these results may not be completely
unexpected, they disclose the importance of metal cation and
solvation effects on the redox properties of RDIs and could
serve to guide the choice of electrolyte or other supporting
media in electrochemical energy storage (EES) devices (e.g.
metal-ion batteries, supercapacitors) incorporating RDIs.
Moreover, the cation effects revealed in the electrochemical
study have been leveraged toward the unusual photochemical
Fig. 4 Solid-state structure of 2. All hydrogen atoms and disordered atoms have been
omitted for clarity. Coordinated THF molecules are shown in wireframe. Pertinent
metrical parameters can be found in the text and ESI.†
We speculate that formation of
2 could proceed by the
elimination of MgCl from or a similar species under dilute
2
1
conditions (Scheme 2). Consequently, we considered that the
bulk microcrystalline solid obtained under concentrated
reaction conditions might contain a physical mixture of the
2−
generation of NDI . UV-Vis spectroscopy experiments indicate
2−
that the formation of NDI proceeds via metal cation-induced
·
−
disproportionation of photogenerated NDI . This novel strategy
single crystal phase of
2
2 and MgCl . However, the peaks
2−
for photogeneration of RDI species may be exploited to
further study the role of this class of molecules for light-driven,
multi-electron transformations. Lastly, chemical reduction of
observed in powder X-ray diffraction patterns acquired for the
microcrystalline solid do not match those in the pattern
simulated from the single crystal structure of
Thus, while the exact structure and composition of
been elucidated, the product does not appear to contain the
single crystal phase of
2
(Fig. S14, ESI†).
2
Dipp NDI with iPrMgCl has led to the first structurally
1
has not
characterized example of a two-electron reduced NDI. Complex
2
+
2
adopts a dimeric structure with strong coordination to Mg
2
.
2−
2−
2
via adjacent O atoms of [Dipp NDI] . Elucidation of the
Given that NDI species are usually represented by the anti
resonance form shown in Scheme 3, the syn coordination mode
structure of
2
along with DFT calculations indicate that NDI2−
2−
prefers a syn versus anti coordination arrangement, and this
insight should serve as a guide for the future design of novel
metal-organic materials based on reduced NDIs. Ongoing work
is focused on investigating the interaction of RDIs with other
metal cations and Lewis acidic species.
of the [Dipp
caught our attention. While kinetic favourability and/or crystal
packing preferences likely facilitate formation of dimer , the
NDI] might also play a role. Bard
2
NDI] groups in the solid state structure of 2
2
2−
electronic structure of [Dipp
2
and Kovak have previously proposed that the syn resonance
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Page 6 of 10
ARTICLE
Journal Name
(
C
58
H
78Cl
2
Mg
2
N
2
O
9
): C, 65.30; H, 7.37; N, 2.63. Found: C, 65.15;
Experimental section
General considerations
View Article Online
DOI: 10.1039/C7DT02067H
H, 7.81; N, 2.62.
Synthesis of 2
All manipulations were carried out using a nitrogen-filled
glovebox or standard Schlenk techniques unless otherwise iPrMgCl (0.50 mL, 2 M in 2-MeTHFl) was added dropwise to a
noted. All glassware was oven-dried in a 150 °C oven before use. solution of Dipp NDI (100 mg, 0.17 mmol) in THF (60 mL). The
2
THF and MeCN were degassed by sparging with ultra-high- resulting red solution was left undisturbed in a sealed vial at
purity argon and dried via passage through columns of drying room temperature for 24 h to afford a mixture of flocculent red
agents using a solvent purification system from Pure Process powder and dense red crystals. The red crystals were manually
Technologies. DMF and DMSO were purified by stirring over separated from the mixture and analysed by single crystal X-ray
CaH
2
followed by vacuum distillation onto 4Å Linde-type diffraction.
NDI was prepared according to
X-ray Crystallography
IPrMgCl was purchased from Sigma
molecular sieves. Dipp
literature procedure.
2
28
Aldrich as a 2 M solution in 2-MeTHF and was used without All operations were performed on a Bruker-Nonius Kappa
further purification. All other chemicals were purchased from Apex2 diffractometer, using graphite-monochromated Mo Kα
commercial vendors and used without further purification. radiation. All diffractometer manipulations, including data
NMR spectra were recorded at ambient temperature on a collection, integration, scaling, and absorption corrections,
1
30
Varian Inova 400 MHz instrument. H NMR chemical shifts were were carried out using the Bruker Apex2 software.
referenced to residual solvent chemical shifts. Solvent- Crystallographic parameters are summarized in Table S1.
1
suppressed H NMR spectra were collected using the WET1D Additional details of the data collection, solution, and
29
sequence with default parameters. ATR-IR spectra were refinement are included in the ESI†.
measured using a Nicolet IR 200 with a diamond ATR accessory.
TGA data were recorded on a TGAQ500 instrument controlled
Computational Details
by TA software. Powder X-ray diffraction patterns were DFT structural optimizations for syn- and anti-H [Dipp NDI] (Fig.
2
2
collected on a Rigaku Miniflex 600 diffractometer using Nickel- S15, ESI†) were carried out using Gaussian09.31 All calculations
filtered Cu-Kα radiation (λ = 1.5418 Å). Elemental analyses were were performed with the B3LYP hybrid functional32 and 6-
performed at Atlantic Microlab, Inc., Norcross, GA.
31++G** basis set for all atoms.33 The crystallographically
reported structure of Dipp
2
NDI with geometrically placed H
Electrochemistry
atoms in the syn or anti positions were used as starting points.2
6
Cyclic voltammetry measurements were carried out in a
nitrogen-filled glovebox in a one compartment cell using a CH
Instruments 600C electrochemical analyzer. A glassy carbon Acknowledgements
electrode and platinum wire were used as the working and
The authors thank Brandeis University for funding and access to
the high-performance computing cluster.
auxiliary electrodes, respectively. A silver wire was used as a
pseudoreference electrode, and potentials are reported
relative to an internal ferrocene reference. Solutions of
electrolyte (0.1 M TBAPF
prepared in the glovebox.
6
) and analyte (1 mM) were also
Notes and references
1
. (a) J. Grajeda, M. R. Kita, L. C. Gregor, P. S. White and A. J.
M. Miller, Organometallics, 2016, 35, 306-316; (b) A. H.
Reath, J. W. Ziller, C. Tsay, A. J. Ryan and J. Y. Yang, Inorg.
Chem., 2017, 56, 3713-3718; (c) S. H. Bae, Y. M. Lee, S.
Photolysis
Photoreduction experiments were carried out in gas-tight
cuvettes using a Rayonet 1070 photochemical reactor with 365
Fukuzumi and W. Nam, Angew. Chem. Int. Ed., 2017, 56
,
nm lamps. Solutions of Dipp
and Et N (0.17 M) were prepared in the glovebox and
transferred to a gas-tight cuvette. The solutions were irradiated
at room temperature and UV vis spectra were recorded at the
2
NDI (8.9 µM), additive (180 µM),
801-805; (d) M. Delgado, J. M. Ziegler, T. Seda, L. N.
3
Zakharov and J. D. Gilbertson, Inorg. Chem., 2016, 55, 555-
57; (e) S. Kakuda, C. J. Rolle, K. Ohkubo, M. A. Siegler, K. D.
Karlin and S. Fukuzumi, J. Am. Chem. Soc., 2015, 137, 3330-
337; (f) J. Park, Y. Morimoto, Y. M. Lee, W. Nam and S.
5
−
3
indicated time points using
spectrophotometer.
a
Cary 50 UV−vis
Fukuzumi, Inorg. Chem., 2014, 53, 3618-3628; (g) B. S.
Dolinar and J. F. Berry, Inorg. Chem., 2013, 52, 4658-4667;
(
h) Y. M. Lee, S. Bang, Y. M. Kim, J. Cho, S. Hong, T. Nomura,
T. Ogura, O. Troeppner, I. Ivanovic-Burmazovic, R. Sarangi,
S. Fukuzumi and W. Nam, Chem. Sci., 2013, , 3917-3923;
i) D. E. Herbert, D. Lionetti, J. Rittle and T. Agapie, J. Am.
Synthesis of 1
2
A solution of Dipp NDI (100 mg, 0.17 mmol) in THF (15 mL) was
4
treated with iPrMgCl (0.50 mL, 2 M solution in 2-MeTHF) at
room temperature. The reaction mixture was stirred briefly and
then allowed to stand for 1 hour. The resulting bright red solid
was collected by centrifugation, washed with THF (2 × 5 mL),
and dried in vacuo to give 85 mg (est. 80% yield) of
Calcd. for Chemical Formula: Dipp NDI(MgClTHF + 1 THF
(
Chem. Soc., 2013, 135, 19075-19078; (j) H. Yoon, Y. M. Lee,
X. Wu, K. B. Cho, R. Sarangi, W. Nam and S. Fukuzumi, J.
Am. Chem. Soc., 2013, 135, 9186-9194; (k) E. Y. Tsui, R.
Tran, J. Yano and T. Agapie, Nat. Chem., 2013,
5, 293-299;
1. Anal.
(l) E. Y. Tsui and T. Agapie, Proc. Natl. Acad. Sci. U.S.A.,
2
2 2
)
6
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 10
Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Journal Name
ARTICLE
10. (a) T. Solomek, N. E. Powers-Riggs, Y. L. Wu, R. M. Young,
2
013, 110, 10084-10088; (m) Y. Morimoto, J. Park, T.
Suenobu, Y. M. Lee, W. Nam and S. Fukuzumi, Inorg. Chem.,
012, 51, 10025-10036; (n) S. Fukuzumi, Y. Morimoto, H.
Kotani, P. Naumov, Y. M. Lee and W. Nam, Nat. Chem.,
010, , 756-759.
View Article Online
M. D. Krzyaniak, N. E. Horwitz and M.
D
R
O
.
I
W
: 10
a
.
s
1
i
0
e
3
l
9
e
/
w
C7
s
D
k
T
i,
02067H
J
.
2
Am. Chem. Soc., 2017, 139, 3348-3351; (b) S. J. Langford,
M. J. Latter and C. P. Woodward, Photochem. Photobiol.,
2006, 82, 1530-1540.
2
2
2
3
. (a) S. Fukuzumi, K. Ohkubo and Y. Morimoto, Phys. Chem.
Chem. Phys., 2012, 14, 8472-8484; (b) S. Fukuzumi and K.
Ohkubo, Coord. Chem. Rev., 2010, 254, 372-385.
11. (a) S. Matsugo, S. Kawanishi, K. Yamamoto, H. Sugiyama, T.
Matsuura and I. Saito, Angew. Chem. Int. Ed., 1991, 30
1351-1353; (b) M. E. Núñez, K. T. Noyes, D. A. Gianolio, L.
W. McLaughlin and J. K. Barton, Biochemistry, 2000, 39
,
. (a) D. Pletcher and H. Thompson, J. Chem. Soc., Faraday
Trans., 1998, 94, 3445-3450; (b) M. Oyama, F. Marken, R.
D. Webster, J. A. Cooper, R. G. Compton and S. Okazaki, J.
Electroanal. Chem., 1998, 451, 193-201; (c) T. Nagaoka, S.
Okazaki and T. Fujinaga, J. Electroanal. Chem. Interfacial.
Electrochem., 1982, 133, 89-99; (d) A. J. Wain, G. G.
Wildgoose, C. G. Heald, L. Jiang, T. G. Jones and R. G.
Compton, J. Phys. Chem. B, 2005, 109, 3971-3978.
,
6190-6199; (c) J. E. Rogers, S. J. Weiss and L. A. Kelly, J. Am.
Chem. Soc., 2000, 122, 427-436; (d) D. A. Vicic, D. T. Odom,
M. E. Núñez, D. A. Gianolio, L. W. McLaughlin and J. K.
Barton, J. Am. Chem. Soc., 2000, 122, 8603-8611; (e) K.
Kawai, T. Takada, T. Nagai, X. Cai, A. Sugimoto, M. Fujitsuka
and T. Majima, J. Am. Chem. Soc., 2003, 125, 16198-16199;
(f) K. Kawai, Y. Osakada, M. Fujitsuka and T. Majima, Chem.
Commun., 2006, 3918-3920.
4
5
. A. G. Bonn and O. S. Wenger, Phys. Chem. Chem. Phys.,
2
015, 17, 24001-24010.
. K. Hernandez-Burgos, G. G. Rodriguez-Calero, W. Zhou, S. E.
Burkhardt and H. D. Abruna, J. Am. Chem. Soc., 2013, 135
4532-14535.
. (a) Z. Song, H. Zhan and Y. Zhou, Angew. Chem. Int. Ed.,
12. (a) S. Chen, Y. Li and C. Wang, RSC Adv., 2015,
15885; (b) S. Chen, D. L. Jacobs, J. Xu, Y. Li, C. Wang and L.
Zang, RSC Adv., 2014, , 48486-48491; (c) A. Monti, J. M. de
5, 15880-
,
4
1
Ruiter, H. J. M. de Groot and F. Buda, J. Phys. Chem. C,
2016, 120, 23074-23082; (d) M. T. Vagnini, A. L. Smeigh, J.
D. Blakemore, S. W. Eaton, N. D. Schley, F. D'Souza, R. H.
Crabtree, G. W. Brudvig, D. T. Co and M. R. Wasielewski,
Proc. Natl. Acad. Sci. U.S.A., 2012, 109, 15651-15656.
6
2
010, 49, 8444-8448; (b) D. J. Kim, S. H. Je, S. Sampath, J.
W. Choi and A. Coskun, RSC Adv., 2012, 2, 7968-7970; (c) G.
S. Vadehra, R. P. Maloney, M. A. Garcia-Garibay and B.
Dunn, Chem. Mater., 2014, 26, 7151-7157; (d) D. Chen, A. J. 13. J. F. Martinez, N. T. La Porte, C. M. Mauck and M. R.
Avestro, Z. Chen, J. Sun, S. Wang, M. Xiao, Z. Erno, M. M.
Algaradah, M. S. Nassar, K. Amine, Y. Meng and J. F.
Stoddart, Adv. Mater., 2015, 27, 2907-2912; (e) G.
Hernández, N. Casado, R. Coste, D. Shanmukaraj, L.
Rubatat, M. Armand and D. Mecerreyes, RSC Adv., 2015,
Wasielewski, Faraday Discuss., 2017, DOI:
10.1039/c6fd00219f.
14. (a) I. Ghosh, T. Ghosh, J. I. Bardagi and B. Konig, Science,
2014, 346, 725-728; (b) L. Zeng, T. Liu, C. He, D. Shi, F.
Zhang and C. Duan, J. Am. Chem. Soc., 2016, 138, 3958-
3961.
5
,
1
7096-17103; (f) F. Xu, S. Jin, H. Zhong, D. Wu, X. Yang, X.
Chen, H. Wei, R. Fu and D. Jiang, Sci. Rep., 2015, 5, 8225; (g) 15. (a) M. de Miguel, M. Álvaro, H. García, F. J. Céspedes-
D. F. Zeigler, S. L. Candelaria, K. A. Mazzio, T. R. Martin, E.
Uchaker, S.-L. Suraru, L. J. Kang, G. Cao and C. K. Luscombe,
Macromolecules, 2015, 48, 5196-5203; (h) M. Veerababu,
U. V. Varadaraju and R. Kothandaraman, Electrochim. Acta,
Guirao, F. Fernández-Lázaro and Á. Sastre-Santos, J.
Photochem. Photobiol. A, 2012, 231, 28-32; (b) M.
Skaisgirski, X. Guo and O. S. Wenger, Inorg. Chem., 2017,
56, 2432-2439.
2
016, 193, 80-87; (i) M. Chen, C. Yang, Z. Xu, Y. Tang, J.
Jiang, P. Liu, Y. Su and D. Wu, RSC Adv., 2016, , 13666-
3669; (j) T. B. Schon, B. T. McAllister, P. F. Li and D. S.
Seferos, Chem. Soc. Rev., 2016, 45, 6345-6404.
16. (a) Y. Pellegrin and F. Odobel, Coord. Chem. Rev., 2011,
255, 2578-2593; (b) L. Hammarstrom, Acc. Chem. Res.,
2015, 48, 840-850.
17. (a) M. Okoshi, Y. Yamada, A. Yamada and H. Nakai, J.
Electrochem. Soc., 2013, 160, A2160-A2165; (b) M. Okoshi,
Y. Yamada, S. Komaba, A. Yamada and H. Nakai, J.
Electrochem. Soc., 2016, 164, A54-A60.
6
1
7
8
. (a) S. V. Bhosale, C. H. Jani and S. J. Langford, Chem. Soc.
Rev., 2008, 37, 331-342; (b) F. Wurthner and M. Stolte,
Chem. Commun., 2011, 47, 5109-5115; (c) F. N. Castellano,
Dalton Trans., 2012, 41, 8493-8501; (d) S. L. Suraru and F.
Wurthner, Angew. Chem. Int. Ed., 2014, 53, 7428-7448; (e)
M. A. Kobaisi, S. V. Bhosale, K. Latham, A. M. Raynor and S.
V. Bhosale, Chem. Rev., 2016, 116, 11685-11796.
. (a) K. Okamoto, Y. Mori, H. Yamada, H. Imahori and S.
Fukuzumi, Chem. Eur. J., 2004, 10, 474-483; (b) S.
Fukuzumi, K. Ohkubo, J. Ortiz, A. M. Gutierrez, F.
Fernandez-Lazaro and A. Sastre-Santos, Chem. Commun.,
2
J. Org. Chem., 2011, 76, 9046-9052; (d) M. Pan, X.-M. Lin,
G.-B. Li and C.-Y. Su, Coord. Chem. Rev., 2011, 255, 1921-
18. S. Fukuzumi, N. Nishizawa and T. Tanaka, J. Chem. Soc.,
Perkin Trans. 2, 1985, 371-378.
19. (a) J. J. Lingane, Chem. Rev., 1941, 29, 1-35; (b) M. J. M.
Nesset, N. V. Shokhirev, P. D. Enemark, S. E. Jacobson and
F. A. Walker, Inorg. Chem., 1996, 35, 5188-5200; (c) M.
Nguyen, T. Phan, E. Van Caemelbecke, X. Wei, J. L. Bear and
K. M. Kadish, Inorg. Chem., 2008, 47, 4392-4400.
20. (a) D. Gosztola, M. P. Niemczyk, W. Svec, A. S. Lukas and M.
R. Wasielewski, J. Phys. Chem. A, 2000, 104, 6545-6551; (b)
C. R. Wade, M. Li and M. Dinca, Angew. Chem. Int. Ed.,
2013, 52, 13377-13381.
005, 3814-3816; (c) L. Tan, G. Zhang, D. Zhang and D. Zhu,
1
936; (e) J.-J. Jiang, C. Yan, M. Pan, Z. Wang, H.-Y. Deng, J.-
21. (a) D. Schmidt, D. Bialas and F. Wurthner, Angew. Chem.
Int. Ed., 2015, 54, 3611-3614; (b) S. Kumar, M. R.
Ajayakumar, G. Hundal and P. Mukhopadhyay, J. Am.
Chem. Soc., 2014, 136, 12004-12010.
R. He, Q.-Y. Yang, L. Fu, X.-F. Xu and C.-Y. Su, Eur. J. Inorg.
Chem., 2012, 2012, 1171-1179.
. C. R. DeBlase, K. Hernandez-Burgos, J. M. Rotter, D. J.
Fortman, S. Abreu Ddos, R. A. Timm, I. C. Diogenes, L. T.
Kubota, H. D. Abruna and W. R. Dichtel, Angew. Chem. Int.
Ed., 2015, 54, 13225-13229.
9
22. S. Seifert, D. Schmidt and F. Würthner, Chem. Sci., 2015, 6,
1663-1667.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Ple aDs ea l dt oo nn To rt a and sj ua sc tt imo na sr gins
Page 8 of 10
ARTICLE
Journal Name
2
3. I. V. Sazanovich, M. A. Alamiry, J. Best, R. D. Bennett, O. V.
View Article Online
Bouganov, E. S. Davies, V. P. Grivin, A. J. Meijer, V. F.
Plyusnin, K. L. Ronayne, A. H. Shelton, S. A. Tikhomirov, M.
Towrie and J. A. Weinstein, Inorg. Chem., 2008, 47, 10432-
DOI: 10.1039/C7DT02067H
1
0445.
2
2
2
2
4. (a) C. A. Zechmann, T. J. Boyle, M. A. Rodriguez and R. A.
Kemp, Polyhedron, 2000, 19, 2557-2564; (b) H. W. Roesky,
M. Scholz and M. Noltemeyer, Chem. Ber., 1990, 123, 2303-
2
309.
5. (a) F. Grepioni, J. Wouters, D. Braga, S. Nanna, B. Fours, G.
Coquerel, G. Longfils, S. Rome, L. Aerts and L. Quéré,
CrystEngComm, 2014, 16, 5887-5896; (b) J. Zhang, Y. Liu, L.
Gong, G. Xu and C. Zhang, Polyhedron, 2016, 109, 67-74.
6. (a) X. X. Wu, S. L. Zhang and S. W. Ng, Acta Crystallogr. Sect.
E, 2011, 67, o3173; (b) L. H. Tong, P. Pengo, W. Clegg, J. P.
Lowe, P. R. Raithby, J. K. M. Sanders and S. I. Pascu, Dalton
Trans., 2011, 40, 10833-10842.
7. (a) S. K. Lee, Y. Zu, A. Herrmann, Y. Geerts, K. Müllen and A.
J. Bard, J. Am. Chem. Soc., 1999, 121, 3513-3520; (b) A.
Viehbeck, M. J. Goldberg and C. A. Kovac, J. Electrochem.
Soc., 1990, 137, 1460-1466.
2
2
3
3
8. E. H. Menke, V. Lami, Y. Vaynzof and M. Mastalerz, Chem.
Commun., 2016, 52, 1048-1051.
9. S. H. Smallcombe, S. L. Patt and P. A. Keifer, J. Magn.
Reson., Ser. A, 1995, 117, 295-303.
0. Apex2, Version 2 User Manual, M86-E01078, Bruker
Analytical X-ray Systems, Madison, WI, June 2006.
1. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M.
A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B.
Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li,
H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L.
Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J.
Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, T. Vreven, J. J. A. Montgomery, J. E. Peralta, F.
Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V.
N. Staroverov, J. N. R. Kobayashi, K. Raghavachari, A.
Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N.
Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V.
Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E.
Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J.
W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski,
G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D.
Daniels, O. Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski
and D. J. Fox, Gaussian 09, Revision A. 02, Gaussian, Inc.,
Wallingford CT, 2009.
3
3
2. (a) A. D. Becke, J. Chem. Phys., 1993, 98, 5648-5652; (b) C.
T. Lee, W. T. Yang and R. G. Parr, Phys Rev B, 1988, 37, 785-
7
89.
3. (a) T. Clark, J. Chandrasekhar, G. W. Spitznagel and P. v. R.
Schleyer, J. Comput. Chem., 1983, , 294-301; (b) M. J.
Frisch, J. A. Pople and J. S. Binkley, J. Chem. Phys., 1984, 80
265-3269; (c) P. C. Hariharan and J. A. Pople, Theor Chim
4
,
3
Acta, 1973, 28, 213-222; (d) P. C. Hariharan and J. A. Pople,
Mol. Phys., 1974, 27, 209-214; (e) W. J. Hehre, R. Ditchfield
and J. A. Pople, J. Chem. Phys., 1972, 56, 2257-2261.
8
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 10
Dalton Transactions
View Article Online
DOI: 10.1039/C7DT02067H
Cyclic voltammetry and X-ray diffraction studies reveal the strength and nature of the
+
2+
interactions between Li /Mg and reduced naphthalene diimides.

Dalton Transactions
Page 10 of 10
View Article Online
DOI: 10.1039/C7DT02067H
3
9x19mm (300 x 300 DPI)