Studies of Nature of Uncommon Bifurcated I-I···(I - M) Metal-Involving Noncovalent Interaction in Palladium(II) and Platinum(II) Isocyanide Cocrystals

Article abstract of DOI:10.1021/acs.inorgchem.1c01591

Two isostructural trans-[MI2(CNXyl)2]·I2 (M = Pd or Pt; CNXyl = 2,6-dimethylphenyl isocyanide) metallopolymeric cocrystals containing uncommon bifurcated iodine···(metal-iodide) contact were obtained. In addition to classical halogen bonding, single-crystal X-ray diffraction analysis revealed a rare type of metal-involved stabilizing contact in both cocrystals. The nature of the noncovalent contact was studied computationally (via DFT, electrostatic surface potential, electron localization function, quantum theory of atoms in molecules, and noncovalent interactions plot methods). Studies confirmed that the I···I halogen bond is the strongest noncovalent interaction in the systems, followed by weaker I···M interaction. The electrophilic and nucleophilic nature of atoms participating in I···M interaction was studied with ED/ESP minima analysis. In trans-[PtI2(CNXyl)2]·I2 cocrystal, Pt atoms act as weak nucleophiles in I···Pt interaction. In the case of trans-[PdI2(CNXyl)2]·I2 cocrystal, electrophilic/nucleophilic roles of Pd and I are not clear, and thus the quasimetallophilic nature of the I···Pd interaction was suggested.

Full text of DOI:10.1021/acs.inorgchem.1c01591

pubs.acs.org/IC
Article
Studies of Nature of Uncommon Bifurcated I−I···(I−M) Metal-
Involving Noncovalent Interaction in Palladium(II) and Platinum(II)
Isocyanide Cocrystals
Margarita Bulatova, Daniil M. Ivanov,* J. Mikko Rautiainen, Mikhail A. Kinzhalov, Khai-Nghi Truong,
Manu Lahtinen, and Matti Haukka*
Cite This: https://doi.org/10.1021/acs.inorgchem.1c01591
Read Online
sı
*
Metrics & More
Article Recommendations
Supporting Information
ACCESS
ABSTRACT: Two isostructural trans-[MI2(CNXyl)2]·I2 (M = Pd
or Pt; CNXyl = 2,6-dimethylphenyl isocyanide) metallopolymeric
cocrystals containing uncommon bifurcated iodine···(metal−
iodide) contact were obtained. In addition to classical halogen
bonding, single-crystal X-ray diffraction analysis revealed a rare
type of metal-involved stabilizing contact in both cocrystals. The
nature of the noncovalent contact was studied computationally
(via DFT, electrostatic surface potential, electron localization
function, quantum theory of atoms in molecules, and noncovalent
interactions plot methods). Studies confirmed that the I···I halogen
bond is the strongest noncovalent interaction in the systems,
followed by weaker I···M interaction. The electrophilic and
nucleophilic nature of atoms participating in I···M interaction was studied with ED/ESP minima analysis. In trans-
[PtI2(CNXyl)2]·I2 cocrystal, Pt atoms act as weak nucleophiles in I···Pt interaction. In the case of trans-[PdI2(CNXyl)2]·I2
cocrystal, electrophilic/nucleophilic roles of Pd and I are not clear, and thus the quasimetallophilic nature of the I···Pd interaction was
suggested.
1. INTRODUCTION
Noncovalent interactions (NCIs) are a powerful instrument
applied in such fields as synthesis,1 catalysis,2,3 design of
photoactive materials,4−6 and biochemistry.7,8 Halogen bond-
ing (XB), in particular, has been found to be a very useful NCI,
for example, in the synthesis of self-assembled polymers,9,10
due to its high directionality and possibilities for fine-tuning.
Recently, XB has been utilized in our research to create
metallopolymeric systems.11 Known types of metal−halide
interactions involved in the self-assembly of metallopolymers
include classical XB12 (Figure 1A) and semicoordination bond
via electron belt (Figure 1C).
Figure 1. Types of NCIs involving metal centers (M) and halogen
In cocrystals of metal complexes, classical XB is represented
by donor/acceptor interaction of an electron-deficient area (σ-
hole) located on a XB donor (XBD) and an electron-rich area
located either on a ligand or on the metal center itself. In the
case of an interaction with square planar d8, linear d10
transition metal complexes, or metal surface, an electron lone
pair on the d orbital acts as the nucleophile, while a σ-hole of a
halogen atom acts as the electrophile. The first examples of the
possible metal-involving XBs were represented by van Koten et
al.13−16 for the I−I···PtII bonds between diiodine and NCN
pincer PtII complexes. Theoretical investigations of these
interactions showed that they are rather strong and comparable
with coordinative bonds.17,18 Further works of van Koten et al.
atoms (drawn as black ovals), where electrophilic regions are colored
as red and nucleophilic ones are colored as blue: metal-involving
halogen bond (A); intermediate metal−halogen interaction (B);
semicoordination bond (C).
Received: May 27, 2021
© XXXX The Authors. Published by
American Chemical Society
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX
A

Inorganic Chemistry
pubs.acs.org/IC
Article
Figure 2. Representations of trans-[MI2(CNXyl)2]·I2 (M = Pd or Pt) polymeric crystal structures visualizing π−π stacking (left) and noncovalent
bifurcated I−I···(I−M) contact (right) in both cocrystals along the a-axis.
Scheme 1. Synthesis of Complexes 1 and 2
showed that the analogous palladium and nickel NCN pincer
complexes interact with diiodine in other ways.19−21 Never-
theless, later works represented metal-involving XB not only
with PtII22−28 and PdII23,27,29,30 but also with NiII,27,31 RhI,32,33
AuI,34−36 and Au0 centers37−41 as nucleophiles.
noncovalently bound metallopolymers. Bearing both an
electron-deficient region of a σ-hole and an electron-rich area
of an electron belt, I2 is prone to interact with both
electrophilic and nucleophilic regions of other molecules.55
In addition, the relatively small size of the I2 molecule allows it
to overcome steric constraints. Furthermore, square planar
trans-[MI2(CNXyl)2] are promising building blocks in organo-
metallic chemistry due to stabilizing metal−carbon π
In contrast to XB, a semicoordination bond31 occurs when
an electrophilic region of a metal center is interacting with the
electron belt of a halogen atom or a nucleophilic halide anion.
Particularly, examples of PdII···I31,42−47 and PtII···I48−50
semicoordination bonds have been described in the literature.
Both types of discussed noncovalent interactions between
metal centers and halogen atoms can be considered polar NCIs
(with clear electrophilic or nucleophilic51 roles assignable to
interacting atoms). In this connection, it is worth noting the
well-defined nonpolar NCIs (with unclear electro- or
nucleophilic roles) between the halogen atoms (type-I
halogen···halogen interactions caused by dispersive forces)3
and metallophilic interactions (closed-shell (d10, s2) or
pseudoclosed shell (d8) weak attractive metal···metal contacts
presumably dominated by electrostatic and dispersion
forces).52 Although possible a nonpolar NCI involving metal
center and halogen atoms is mentioned for the so-called C−I···
Ni boundary case,31 the nature of nonpolar interaction (such as
philicity of interacting centers and energy components)
between halogen and metal atoms has never been studied
thoroughly prior to this work.
interactions.56,57 An occupied dz orbital of these Pd and Pt
2
complexes is accessible for interaction, which opens up the
opportunity for the generation of metal−involving XB systems.
In the current work, molecular iodine forms isostructural
metallopolymeric cocrystals, trans-[MI2(CNXyl)2]·I2 (M = Pd
or Pt), where complex units are noncovalently linked via I2
molecules (Figure 2). Careful analysis of experimental and
theoretical data along with a literature search revealed atypical
I−I···(I−M) bifurcated noncovalent bonds, in which classical
halogen bond is additionally stabilized by an uncommon type
of an I···M contact between a metal center and halogen atom.
In this contact, the halogen atom is neither interacting via a σ-
hole (Figure 1A) nor via an electron belt (Figure 1C), but
presumably via a transitional area (Figure 1B). To understand
the nature of this intermediate contact, it was comprehensively
studied with various bond analysis methods such as electro-
static surface potential (ESP) analysis (to discover the angle
limits of a σ-hole), NCIs plot (NCI-plot) analysis (to reveal
the relative strength of the interaction), electron density (ED)/
ESP analysis (to assign philicity of the interacting atoms), and
local energy decomposition (LED) analysis (to indicate which
interaction type best describes the contact).
As a continuation of our studies of metal-involving
interactions53 and halogen bonding,26 especially between
molecular iodine and iodide isocyanide complexes,53,54 the
association of molecular iodine with trans-[MI2(CNXyl))2] (M
= Pd (1) or Pt (2); CNXyl = 2,6-dimethylphenyl isocyanide)
species was studied. The simple structure of molecular iodine
allows a high level of control in the self-assembly of
B
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Table 1. Characteristic Parameters of Selected Noncovalent Interactions in the Crystal Structures of 1·I2 and 2·I2
cocrystal
contact
I···I
a
I−I···I−Pd
d(I···I), Å
∠(I−I···I), deg
∠(I···I−Pd), deg
RIX
I3−I4···I1−Pd1
I4−I3···I2−Pd2
3.4986(11)
3.5034(11)
173.07(3)
173.10(3)
I···Pd
65.82(2)
65.74(2)
0.88
0.88
1·I2
a
I−I···Pd−I
d(Pd···I), Å
∠(I−I···Pd), deg
∠(I···Pd−I), deg
RIX
I3−I4···Pd1−I1
I4−I3···Pd2−I2
3.4038(8)
3.4038(8)
128.58(3)
128.64(3)
I···I
65.82(2)
65.74(2)
0.94
0.94
1·I2
2·I2
2·I2
a
I−I···I−Pt
d(I···I), Å
∠(I−I···I), deg
∠(I···I− Pt), deg
RIX
I3−I4···I1−Pt1
I4−I3···I2−Pt2
3.5195(9)
3.5206(9)
172.13(3)
172.31(3)
I···Pt
66.875(17)
66.751(17)
0.89
0.89
a
I−I···Pt−I
d(Pt···I), Å
∠(I−I···Pt), deg
∠(I···Pt−I), deg
RIX
I3−I4···Pt1−I1
I4−I3···Pt2−I2
3.4648(6)
3.4601(6)
128.10(3)
128.27(3)
69.092(17)
69.207(17)
0.93
0.93
a
RIX = d(I···X)/(RIvdW + RXvdW), where RIX is distance reduction ratio, I is a donor atom, X is an acceptor atom (I, Pt, Pd), and d(I···X) is the
distance between I and X in Å; RIvdW and RX are the vdW radii of I and X correspondingly determined by Bondi.63
vdW
Table 2. M−I and I−I Distances in the Single Crystals of the trans-[MI2(CNXyl)2] Complexes, Corresponding Cocrystals, and
I2 Molecule65
1
1·I2
2
2·I2
I2
2.6156(7)
2.6158(7)
2.7264(9)
2.6179(6)
2.6187(6)
2.7400(11)
d(M−I), Å
d(I−I), Å
2.5950(4)
2.6028(4)
2.7179(2)
3.86−3.88 Å in 1·I2 and 3.87−3.91 Å in 2·I2 (Figure 2),
whereas in original 1 and 2 complexes, this type of stacking is
not observed.
2. RESULTS AND DISCUSSION
2.1. Complexes 1 and 2 and Their Cocrystals.
Syntheses of complexes trans-[PdI2(CNXyl)2]58 (1) and
trans-[PtI2(CNXyl)2]59 (2) are presented in Scheme 1. A
similar trans-[PdBr2(CNXyl)2] complex60 has been described
previously. Cocrystals 1·I2 and 2·I2 were grown from 1:1
CH2Cl2/CHCl3 and CHCl3 solutions of a 1:1 mixture of the
corresponding complex and I2, respectively.
The relative strengths of NCIs can be approximated by a
comparison of the experimentally obtained distances between
noncovalently interacting atoms and the sum of corresponding
van der Waals radii (vdW).62 The distance reduction ratio of
NCI (RIX) can be calculated as RIX = d(I···X)/(RIvdW + RXvdW),
where I (iodine) represents a halogen bond donor (XBD)
atom, X is a halogen bond acceptor (XBA) atom, d(I···X) is
the distance between I and X in Å, and RIvdW and RXvdW are the
vdW radii by Bondi63 of I and X in Å, respectively. The
comparison shows that the characteristic parameters of the
interactions correlate closely with each other emphasizing the
isostructural nature of cocrystals (Figure 2, Table 1).
The uncommon bifurcated I−I···(I−M) contact can be
subdivided into two types of NCIs: I···I and M···I. Within the
cocrystals, the relative strength of the XB is rather similar: For
I···I XB, RIX is 0.88 for 1·I2 and 0.89 for 2·I2; for M···I
interaction, RIX is 0.94 for 1·I2 and 0.93 for 2·I2. Hence, in both
cocrystals I···I XB is slightly stronger than M···I interaction.
This might indicate the main role of I···I XB in the interaction
(which is further confirmed in theoretical analysis of the
structures, vide infra). Another parameter attracting attention
is the ∠I−I···M angle in both cocrystals, which is significantly
more acute (about 128°) than that of classical XB (180°)12
(Table 1). Variation of this parameter brings up a question on
the nature of I···M interaction; thus, it was further studied
computationally.
2.2. Single-Crystal X-ray Diffraction (SCXRD) Analysis.
Although syntheses of 158 and 261 are known, no SCXRD data
was found for these complexes in the Cambridge Structural
Database (CSD). Isostructural complexes 1 and 2 exhibit the
same monoclinic lattice of the P21/c space group (for details,
see the Supporting Information, “Single crystal X-ray
Diffraction Data Analysis (SCXRD)” section). The complexes
have square-planar structures with iodide ligands in the trans
position to each other. Cocrystals of 1·I2 and 2·I2 have both a
1:1 molar composition; exhibit the same triclinic lattice P1
̅
space group, and similar unit cell parameters, being
isostructural to the original complexes. The fragments C−
N−C−M are almost linear in both complexes (∠(Pd−C−N)
= 179.2(4)° and ∠(Pt−C−N) = 178.6(4)°) and correspond-
ing cocrystals (∠(Pd−C−N) = 179.4(10)° and ∠(Pt−C−N)
= 179.0(12)°). The most notable difference between original 1
and 2 complexes and the corresponding cocrystals is in the
position of the iodide ligands: While in 1 and 2 the iodide
ligands are located in the same plane as the xylene rings of the
CNXyl ligands, in cocrystals the iodide ligands are tilted away
from the plane allowing interaction of I2 molecule with the
complex. Additionally, in cocrystals CNXyl ligands are
arranged in π−π stacks with centroid−centroid distances of
The I···Pd distances in 1·I2 are shorter by ∼0.06 Å than the
same I···Pt distances in 2·I2 (Table 1). At the same time, the
C
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Figure 3. Electrostatic potential calculated at the M06L/def2TZVP/def2TZV computational level on the 0.001 a.u. molecular surface of I2, 1, and 2
with the color scale from −102 kJ mol−1 to 102 kJ mol−1.
electron density values in the corresponding I···M bond critical
points (BCPs) are similar (the difference is less than 0.001 a.u.,
see Table 3 in section 2.3.2). According to these observations,
the vdW Pd radius may be similar or only slightly shorter than
the Pt radius. This hypothesis is in disagreement with Bondi’s
vdW radii (1.63 Å for Pd vs 1.75 Å for Pt),62 and further
detailed studies should be carried out in this direction.
Comparing M−I bond length in the cocrystals and in the
corresponding complexes (Table 2), we observed elongation of
the M−I bond in cocrystals, presumably due to a strong
influence of the halogen bonding with I2 in the cocrystals. This
elongation was also found in a few other cocrystals of square
planar Pt complexes having different XBDs,22,64 and the M−I
bond elongation is likely to be found in similar systems of
square planar transition metal complexes interacting with XBD.
The I−I bond length is elongated in 1·I2 and 2·I2 cocrystals
in comparison to that in the solid-state structure of I265 (Table
2). This elongation of a covalent bond in XBD is typical for a
XB according to IUPAC XB definition.12
Although according to RIX value halogen bonding seems to
be the strongest NCI, it is important to take into consideration
the combination of all the involved NCIs like I···M interaction
and π−π stacking. The significance of the discussed
interactions for the structure arrangement was further
elucidated by various computational methods (see the
“Theoretical Studies” section and the “QTAIM Analysis”
section of the Supporting Information, where QTAIM =
quantum theory of atoms in molecules).
2.3. Theoretical Studies of Noncovalent Interactions.
With the help of computational chemistry, the nature and
relative strength of NCIs discovered by SCXRD can be
thoroughly studied. Careful analysis of the calculated electron
density distribution can reveal NCIs and their properties. A
combination of several approaches such as analysis of ESP,66,67
NCI-plot68 analysis, combined electron localization function
(ELF)69 and Bader’s quantum theory of atoms in molecules
(QTAIM) analysis,70 and LED71 analysis gives a broad look on
NCIs. To support the idea that observed interactions are not
only caused by packing effects, the data of single-point (SP)
structures and optimized (OPT) ones were compared (for
more details, see the Experimental Section).
electrostatic intermolecular interactions. This helps to estimate
the geometries and expected strengths of the XB interactions.
The strength of the XB formed by the XBD is related to the
magnitude of σ-hole77 on the XBD atom that can be described
by the maximum of ESP (Vs,max). The influence of the XBA on
the XB can be estimated using the minimum of ESP (Vs,min) on
the XBA atom electron density surface. ESP analysis was
carried out on the 0.001 a.u. contour of molecule’s electron
density (that encompasses 96% of the molecular charge).78
Anisotropic charge distributions of I2, trans-[PdI2(CNXyl)2]
(1), and trans-[PtI2(CNXyl)2] (2) were analyzed, and the
corresponding ESPs are represented in Figure 3. An electron-
deficient area corresponding to the σ-hole of the I2 molecule
was calculated with Vs,max = 139 kJ mol−1 which is reasonably
−1
́
̌
close to the Vs,max value (127 kJ mol ) reported by Kolar et
al.79 at much higher ab initio QCISD/def2-QZVP level of
theory. As was suggested by the X-ray diffraction analysis, the
I2 molecule is expected to behave in the cocrystals as a XBD,
interacting with complexes 1 or 2 that act as XBAs. To
participate in XB, complexes 1 and 2 are required to bear an
electron-rich area around the I or M (M = Pd or Pt) atom.
Indeed, ESP studies of 1 and 2 confirm the electron-rich areas
(Vs,min) for iodine atoms (Vs,min = −102 kJ mol−1) and for the
Pd (Vs,min = −81 kJ mol−1) and Pt centers (Vs,min = −89 kJ
mol−1). These local nucleophilic areas roughly correlate with
the regions of I···I and I···M interactions.
To analyze if the uncommon I···M contact could be caused
by XB-type interactions, we determined the σ-hole limiting
angle80 [∠(I−I···XBA)] for the I2 molecule. The σ-hole
limiting angle helps to estimate the angle range where
nucleophilic atom can approach the electron-deficient area of
I atom with a favorable electrostatic attraction. The limits of
the interaction with the σ-hole were found to be 115−180°
(see Figure S4). In the case of 1·I2 and 2·I2 cocrystals, ∠(I−I···
M) is around 128° allowing M atoms to interact with the σ-
holes of I2. While this provides evidence of the likely existence
of I···M interaction, it does not give direct information on the
nature of the interaction and further computational analyses
were carried out to achieve this.
2.3.2. NCI-plot Analysis. NCI-plot analysis is a powerful
method to reveal the repulsive or attractive nature of the
interaction and to describe the relative strength of noncovalent
bonding.81,82 2D and 3D NCI-plots visualizing all the
interactions in 1·I2 and 2·I2 cocrystals can be found in Figures
2.3.1. ESP Analysis. Observed NCIs can be clarified by
analysis of anisotropic charge distribution, which is visualized
by ESP.3,67,72−76 ESP visualizes electron-rich and -deficient
areas of the molecule that are likely to participate in
D
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Figure 4. NCI visualizations of the bifurcated contact for SP (left) and OPT (right) trans-[MI2(CNXyl)2]4·I2 clusters (where M = Pd or Pt).
Corresponding 2D graphs, as well as full 3D visualizations containing all the interactions, can be found in Figures S8−S13.
S8−S13. Here only the interactions involved in the bifurcated
contact are discussed.
For (1)4·I2 and (2)4·I2 clusters 2D plots of (s) against
sign(λ2)ρ have a similar shape (see Figures S8 and S9). Two
types of attractive NCIs (I···I and I···M XBs, where M = Pt or
Pd) were found in the [−0.02, −0.008] a.u. range of sign(λ2)ρ
and one type of repulsive interaction found in the [0.009,
0.018] a.u. range of sign(λ2)ρ (Figure 4). The repulsion areas
for the I−I···(I−M) interactions can be explained by the
repulsion of lone pairs of the metal center and iodide ligand in
1 and 2; the same areas can be found in isolated 1 and 2 (see
the sign(λ2)ρ projections in Figure S14). Expectedly, the
strength of XB in both cocrystals was found to be very similar.
This observation correlates with data obtained experimentally
(see Table 1).
Especially intriguing is the difference between SP and OPT
Figure 5. ELF projections with plotted contour lines (black, step is
0.05), bond paths (white lines), BCPs (blue dots), nuclear critical
points (NCPs, brown dots), ring critical points (RCPs, orange dots),
and cage critical points (green dots) for the I−I···I and I−I···M
interactions in the SP (1)4·I2 (upper left), OPT (1)4·I2 (upper right),
SP (2)4·I2 (lower left), and OPT (2)4·I2 (lower right) model clusters.
structures. As expected, the strength of all interactions weakens
in the optimized structures (Figure 4, Table 3). In the case of
SP structures, I···I and I···M contacts have very similar
interaction strengths, while in the OPT structures I···M contact
is weaker. In the case of (2)4·I2, the change is more noticeable
(i.e., interactions are more weakened) than that in the case of
(1)4·I2 (Table 3).
structures, the I−I···(I−M) bond paths go through the
increased ELF areas on the iodides (i.e., through the lone
pairs) and through decreased ELF regions on the diiodine I
atoms (i.e., through the σ-holes). These observations support
the XB nature of the I−I···(I−M) contacts where iodide
ligands behave as nucleophiles toward electrophilic diiodine
molecules. Similar behavior was observed in the case of the I−
I···(I−Pt) XBs in [PtI2(1,5-cyclooctadiene)]·0.5I2 in our
previous work,26 where the I···I bond paths go through the
σ-hole (iodine in I2) and the lone electron pair (iodide ligand)
ELF regions.
Table 3. Peak sign(λ2)ρ Values of NCIs in the (1)4·I2 and
(2)4·I2 (a.u.)
cluster
(1)4·I2, M = Pd
(2)4·I2, M = Pt
peak sign(λ2)ρ, a.u.
peak sign(λ2)ρ, a.u.
interaction
SP
OPT
SP
OPT
I4···I1
−0.0167
−0.0154
−0.0164
−0.0145
I3···I2
I4···M1
I3···M2
−0.0159
−0.0119
−0.0160
−0.0099
ELF projections show increased ELF areas around Pd and Pt
atoms above and below the bond paths connecting metal
2
2.3.3. Philicity Definition: Analysis of ELF and ED/ESP
Minima. ELF is useful in the investigation of XBs and related
interactions.24,83−89 As a derivative of electron density
ELF69,90−92 allows to locate areas of shared and unshared
electron pairs. A combination of ELF and QTAIM70 methods
visualizes bond paths at the interaction areas and facilitates
defining the philicity of interacting atoms.26,93
Combined ELF and QTAIM analysis information for SP and
OPT (1)4·I2 and (2)4·I2 model structures is presented in
Figure 5 as projections on a plane formed by metal atoms,
iodide ligands, and iodine molecules. In all four analyzed
centers and iodide ligands that can be interpreted as filled dz
orbitals. The M···I bond paths that connect metal centers and
2
I2 molecules go through these dz orbitals. However, the ELF
values suggest only relatively weak concentrations of electron
2
pairs in areas occupied by dz orbitals and the areas lack
directional dependence outside the plane formed by metal
centers and iodide ligands suggesting that metal centers are
likely to act as weak nucleophiles at most. Actually, any bond
path corresponding to NCI with the metal center would cross
the area of dz orbitals, because any d8-metal-involving
2
interaction is required to stay away from the ligands in the
E
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Figure 6. 1D profiles of the ED (black) and ESP (red) functions along the I···Pd bond paths in (1)4·I2 for SP (upper graphs) and OPT (lower
graphs) structures.
Figure 7. 1D profiles of the ED (black) and ESP (red) functions along the Pd···Pd bond path in (cis-[PdCl2(CNPh)2])2 (left) and the Pt···Pt bond
path in (cis-[PtCl2(CNPh)2])2 (right).
Figure 8. 1D profiles of the ED (black) and ESP (red) functions along the I···Pt bond paths in (2)4·I2 SP (upper graphs) and OPT (lower graphs)
structures.
complex plane, and the nature of the NCI will depend more on
the atom of the interacting partner. At the same time, in all
four clusters the I···M bond paths connect to I2 iodine atoms
through areas with intermediate ELF values which could
indicate that the interactions are either weakly polar or
nonpolar. Since the I···M bond paths connect atoms in each
structure through areas described by intermediate ELF values,
combined ELF and QTAIM analysis does not provide
conclusive evidence on the philicity of atoms in these
interactions.
An alternative way to assign philicity of noncovalently
interacting atoms is to compare the minima of the electron
density (ED) and ESP along the bond path.24,87,88,94−97 In
polar NCIs the minimum of ESP is shifted toward the
nucleophilic atom, while the ED minimum is shifted toward
the electrophilic atom. In the case of the I−I···(I−M)
interactions (M = Pd or Pt), 1D profiles of the ED and ESP
functions along the I−I···I−M bond paths confirm the iodide
nucleophilicity toward diiodine in all four clusters as shown in
Figures S15 and S16.
F
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Figure 9. Fragments of (trans-[MI2(CNXyl)2])2·I2 structures (M = Pd or Pt) used in the local energy decomposition analysis.
In the case of I···Pd bond paths in (1)4·I2, the 1D profiles of
the ED and ESP functions (Figure 6) show that their minima
overlap both in the SP and OPT structures. Together with the
combined ELF and QTAIM analysis information, this suggests
that I···Pd interactions are best described as nonpolar with Pd
and I atoms having similar roles. It is noteworthy that similar
interactions, which can be also called intermediate between
semicoordination (electrophilic metal center) and metal-
involving halogen bonding (nucleophilic metal center), have
been previously reported for a Ni(II) complex.31
nucleophiles toward I2 iodine atoms, and the I−I···Pt can be
treated as metal-involving halogen bonding.22,23,25 Interestingly
the more nucleophilic character of PtII compared to PdII in
isostructural cocrystals was previously observed for the X2CH−
X···M (X = Br and I; M = Pd or Pt) halogen bonding.23
However, the small values of the shifts between ED and ESP
minima and the ∠(I−I···Pt) angles (128.1−128.3° in SP and
126.5° in OPT structures) that are far from linear leave open
the possibility of considering the I···Pt interactions as having
intermediate31 philicity i.e. treating them as nonpolar
interactions.
The nonpolar noncovalent I···Pd interactions in (1)4·I2 are
reminiscent of the noncovalent metal center involving
interactions in related palladium and platinum chloride
isocyanide complexes,98−101 where metal centers participate
in nonpolar metallophilic Pd···Pd and Pt···Pt bonds. To
compare these interactions DFT SP calculations (M06-L/def2-
TZVP) were carried out for two model clusters (cis-
[PdCl2(CNPh)2])2 and (cis-[PtCl2(CNPh)2])2, based on the
experimental X-ray data from the structures COYBOI01 and
CPICPT12,99 respectively. Combined ELF and QTAIM
analysis of the (cis-[MCl2(CNPh)2])2 (M = Pd or Pt) clusters
indicated the expected existence and nonpolar noncovalent
nature of the Pd···Pd and Pt···Pt interactions (see Figure S18).
Further confirmation of the nonpolar nature of the metal-
lophilic interactions is provided by the 1D profiles of the ED
and ESP functions along the M···M bond paths in (cis-
[MCl2(CNPh)2])2 (M = Pd or Pt) clusters (Figure 7) where
ED and ESP minima overlap in both cases.
The ED/Laplacian of ED values in Pd···Pd (0.012/0.030
a.u.) and Pt···Pt (0.016/0.038 a.u.) BCPs in (cis-
[MCl2(CNPh)2])2 clusters are similar to the values in the
I···Pd BCPs in (1)4·I2 SP (0.016/0.037−0.038 a.u.) and
(0.012/0.027 a.u.) OPT structures. The nonpolarity of the I···
Pd interactions in (1)4·I2 and the similarity of their strength to
metallophilic interactions leads us to designate them as
quasimetallophilic interactions.
2.3.4. LED Analysis. The relative energy contributions
different types of interactions have to the total interaction can
be estimated with local energy decomposition (LED)
analysis.102 To elucidate the nature of the I···M and I···I
interactions, further local energy decomposition (LED)
analysis71 on DLPNO−CCSD(T)103−105/def2-TZVPP106,107
wave function for fragments depicted in Figure 9 was carried
out. The LED analysis results are given in Table 4.
Comparison of the interaction energies between fragments 6
(I2) and 7 (trans-[MI2(CNXyl)2], M = Pd or Pt) with energies
between fragments 2 (I) and 6 suggest that the interaction
between I2 and trans-[MI2(CNXyl)2] in both cocrystals of Pd
and Pt complexes is almost solely due to the XB between I2
and iodide coordinated to M. The interaction between M atom
and I2 appears to have only a minor supporting role to the total
interaction between I2 and the complex. This conclusion is in
accordance with SCXRD analysis data (based on RIX index, I···
I XB is slightly stronger than I···M, Table 1). The I···I2 XB
interaction is classified as mainly electrostatic by the LED
analysis with small covalent and dispersion contributions. The
weaker I···M interaction has higher contributions from
covalent and dispersion terms than does the stronger I···I XB
interaction in line with the other analyses that described the I···
M interaction as weakly polar or nonpolar.
3. CONCLUSION
Comparison of the 1D profiles of ED and ESP along the I···
Pt bond paths in (2)4·I2 SP and OPT structures (Figure 8)
shows that the ESP minima are slightly shifted toward the Pt
atoms. The shift indicates that Pt atoms act as weak
Two novel cocrystals of trans-[MI2(CNXyl)2]·I2 (where M =
Pd or Pt) representing noncovalently linked metallopolymeric
structures were synthesized and characterized. Analysis of
G
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
interactions were studied with the NCI-plot program68 implemented
in Critic2 software,111 and 2D and 3D visualizations were carried out
in Gnuplot112 and VMD programs113 respectively. ESP surfaces of 1,
2, and I2 molecules were calculated and visualized using AIMALL
software114 at 0.001 a.u. surfaces. ELF projections and QTAIM
analyses were carried out in Multiwfn 3.7.115 DLPNO−CCSD-
(T)103−105 wave functions for the LED analyses,71 and the analyses
themselves were calculated with ORCA 4.2 program116 using def2-
TZVPP106 orbital and def2-TZVPP/C107 and def2/JK117 auxiliary
basis sets.
4.2. Materials and SCXRD Details. All chemicals and solvents
such as CHCl3 (VWR BDH Chemicals), CH2Cl2 (VWR BDH
Chemicals), acetone (Fisher Scientific), KI (≥99.0%, Fisher
Scientific), I2 (Mallinckrodt), 2,6-dimethylphenyl isocyanide (further
CNXyl, ≥98.0 GC%, Aldrich), and [PdCl2(CH3CN)2] (99%,
Aldrich) were used without additional purification. [PtI2COD] was
synthesized according to the procedure reported by Rigamonti et al.61
The crystal data and details of data processing for the obtained
cocrystals are summarized in the Supporting Information (“Single
Crystal X-ray Diffraction data analysis (SCXRD)” section).
Caution! CNXyl is hazardous to health and should be handled with
care.
4.2.1. Synthesis of trans-[PdI2(CNXyl)2]. Synthesis was adapted
from a procedure presented by Crociani et al.58 Solid CNXyl (26.2
mg, 0.2 mmol) was added to the suspension of [PdCl2(CH3CN)2]
(25.9 mg, 0.1 mmol) in 5 mL of CHCl3. The reaction mixture was
refluxed with stirring for 3 h and then cooled to room temperature
(RT), and the solvent was evaporated at a rotary evaporator to give
cis-[PdCl2(CNXyl)2] as a white solid. Then solid KI (166 mg, 1
mmol) was added to cis-[PdCl2(CNXyl)2] (43.7 mg, 0.10 mmol), and
acetone (20 mL) was added to the resulting mixture. The resultant
yellow suspension was stirred at RT for 2 days. The solvent was then
fully evaporated on a rotary evaporator at 50 °C, and the orange
product was suspended in H2O. The product was extracted with
CH2Cl2. The organic fraction was subjected to full solvent
evaporation on a rotary evaporator, and the resulted orange solid
was dissolved in CHCl3. Some white insoluble material was filtered off
from solution; the filtrate was left for recrystallization at RT in
darkness (from CHCl3). The yield of orange crystalline product was
55.6 mg (0.09 mmol, 89%). Elemental analysis (EA) CHN mode:
Found: C 35.72; H 3.22; N 4.44. Calcd: C 34.73; H 2.91; N 4.50. 1H
NMR (300 MHz, CDCl3, δ ppm): 2.55 (s, 12H), 7.09−7.14 (m, 4
H), 7.21−7.28 (m, 2H).
4.2.2. Synthesis of I2 Cocrystal of trans-[PdI2(CNXyl)2]. trans-
[PdI2(CNXyl)2] (24.9 mg, 0.04 mmol) and I2 (15.2 mg, 0.06 mmol)
were dissolved in CH2Cl2/CHCl3 (50:50 mixture, 8 mL). The
solution was stirred at 50 °C (to dissolve iodine fully) until the
mixture became homogeneous and then left for crystallization in dark
at RT. The phase purity of the bulk material was confirmed by
powder X-ray diffraction (PXRD, see the Supporting Information).
4.2.3. Synthesis of trans-[PtI2(CNXyl)2]. Synthesis was adapted
from a procedure presented by Kaharu et al.59 [PtI2COD] (83 mg,
0.15 mmol) was added to a 5 mL of CH2Cl2 solution of a CNXyl
(39.4 mg, 0.3 mmol), and the mixture was stirred for 3 days at RT in
darkness. The solvent was evaporated, and obtained solid was
crystallized from CH2Cl2. TLC (silica gel 60 plate + CHCl3) revealed
byproducts. The product was purified by column chromatography
(silica gel 60 + CHCl3) and recrystallized from CHCl3. The yield of
yellow crystalline product was 99.8 mg (0.14 mmol, 93%). EA CHN
mode: Found: C 31.83; H 2.81; N 4.11. Calcd: C 30.40; H 2.55; N
3.94. 1H NMR (300 MHz, CDCl3, δ ppm): 2.58 (s, 12H), 7.14−7.18
(m, 4 H), 7.26−7.32 (m, 2H).
Table 4. Energy Components of the Interfragment
Interaction Energies (kJ mol−1) in (1)2·I2 and (2)2·I2
Cocrystals Calculated at DLPNO−CCSD(T)/def2-TZVPP
a
Level
cocrystal
interaction
Eexch
Eelstat
EDISP
E(T)
Esum
1 ↔ 6
2 ↔ 6
6 ↔ 7
1 ↔ 6
2 ↔ 6
6 ↔ 7
−11
−64
−82
−10
−55
−69
−28
−254
−295
−27
−243
−288
−4
−11
−26
−5
−10
−29
−1
−4
−8
−1
−4
−7
−44
−333
−411
−43
−312
−392
(1)2·I2
(2)2·I2
a
Exchange interaction, Eexch; electrostatic and polarization energy,
elstat; dispersion interaction, EDISP; and contribution from triples
E
correction, E(T). Only interactions of interest are represented in this
table, detailed information on all the interactions can be found in
Supporting Information (Tables S8−S9). Electronic preparation
energies resulting from intrafragment changes in electron density
and deformation energies due to geometrical differences of fragments
in interacting structure compared to their separated equilibrium
geometries that are required to derive the dissociation energies
corresponding to the analyzed interactions have not been included in
the analysis.
crystal structure showed that trans-[MI2(CNXyl)2] units are
interlinked via an uncommon I−I···(I−M) bifurcated contact
with the I2 molecule. Bifurcated contact, in turn, can be
subdivided into a I···I halogen bond and a I···M metal-
involving interaction. To reveal the nature of the contact, it
was studied with various computational methods such as NCI-
plot, QTAIM and LED analyses, and ED/ESP minima
comparisons. It was shown that the I···I halogen bond is the
strongest NCI stabilizing the system, supported by a weaker I···
M metal-involving interaction. ED/ESP minima comparisons
showed the nonpolarity of I···M contact in the
[PdI2(CNXyl)2]·I2 cocrystal; therefore, this interaction was
suggested to be called quasimetallophilic. In the case of the
[PtI2(CNXyl)2]·I2 cocrystal, similar studies showed the weakly
nucleophilic nature of Pt center, which makes the I···Pt
interaction polar and is best described as metal-involving
halogen bonding. However, the differences between the I···Pd
and I···Pt interactions are not crucial for directed crystal
engineering, and the Pd/Pt isostructural exchange can be
further used in the design of similar Pd- and Pt-containing
cocrystals.
4. EXPERIMENTAL SECTION
4.1. General Computational Details. All the studied structures
were optimized and analyzed using DFT theory. To achieve a good
compromise between accuracy and computational demand for
calculating systems containing NCIs M06-L functional108 combined
with triple-ζ def2-TZVP106 basis sets was chosen as the calculation
method. To further reduce computational time resolution of identity
approximation109 together with def2-TZV density fitting basis sets106
was employed in the calculations. DFT calculations were carried out
with Gaussian16 (revision C.01) program package.110 Complexes 1
and 2 and I2 were subjected to full energy minimization. Models for
solid-state clusters (1)4·I2 and (2)4·I2 were directly cut from the
corresponding experimental crystal structures. Bonding analyses of
NCIs in model structures (1)4·I2 and (2)4·I2 were carried out on both
optimized (OPT) and crystal structure derived SP structures (where
only positions of H-atoms were optimized). SP calculations (M06-L/
def2-TZVP) were also carried out for two model clusters, (cis-
[PdCl2(CNPh)2])2 and (cis-[PdCl2(CNPh)2])2, based on the
experimental X-ray data from the structures COYBOI01 and
CPICPT12,99 respectively. The strength and topology of the
4.2.4. Synthesis of I2 Cocrystal of trans-[PtI2(CNXyl)2]. trans-
[PtI2(CNXyl)2] (21.3 mg, 0.03 mmol) and I2 (15.2 mg, 0.06 mmol)
were dissolved in CHCl3, and the resulting dark brown mixture was
left in an aluminum foil covered vial for slow evaporation at ambient
conditions to give dark brown crystals of the desired product. The
phase purity of the bulk material was confirmed by PXRD analysis
(see Supporting Information).
H
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
written through the contributions of all authors. All authors
have approved the final version of the manuscript.
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.inorgchem.1c01591.
■
sı
Funding
This work was supported by the Academy of Finland (project
no. 295581). Part of the theoretical investigations (ELF and
QTAIM analysis, ED/ESP minima analysis) were supported by
the Russian Science Foundation (project no. 19−73−10016
for D.M.I.).
Single-crystal X-ray diffraction data analysis (experimen-
tal procedures and crystallographic details); PXRD of 1·
I2 and 2·I2 cocrystals (experimental procedures and
detailed results of PXRD analysis); summary of
computational studies on NCIs in 1·I2 and 2·I2
cocrystals (general computational details, ESP,
QTAIM, LED, and NCI-plot analyses, ED/ESP minima
criterion for I···I interactions); view of (cis-
[MCl2(CNPh)2])2 (M = Pd or Pt) dimeric clusters
and ELF projections for them (PDF)
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank Prof. V. Yu. Kukushkin for his help with manuscript
preparation. The Finnish Grid and Cloud Infrastructure
(urn:nbn:fi:research-infras-2016072533) and Prof. H. M.
Tuononen (University of Jyväskylä) are gratefully acknowl-
edged for the provision of computational resources.
Accession Codes
CCDC 2054859−2054862 contain the supplementary crys-
tallographic data for this paper. These data can be obtained
free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by
emailing data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
REFERENCES
■
(1) Maharramov, A. M.; Mahmudov, K. T.; Kopylovich, M. N.;
Pombeiro, A. J. L. Non-Covalent Interactions in the Synthesis and Design
of New Compounds; John Wiley & Sons, Ltd., 2016.
AUTHOR INFORMATION
Corresponding Authors
■
(2) Mahmudov, K. T.; Gurbanov, A. V.; Guseinov, F. I.; Guedes da
Silva, M. F. C. Noncovalent Interactions in Metal Complex Catalysis.
Coord. Chem. Rev. 2019, 387, 32−46.
(3) Cavallo, G.; Metrangolo, P.; Milani, R.; Pilati, T.; Priimagi, A.;
Resnati, G.; Terraneo, G. The Halogen Bond. Chem. Rev. 2016, 116
(4), 2478−2601.
(4) Koshevoy, I. O.; Krause, M.; Klein, A. Non-Covalent
Intramolecular Interactions through Ligand-Design Promoting
Efficient Photoluminescence from Transition Metal Complexes.
Coord. Chem. Rev. 2020, 405, 213094.
(5) Wang, W.; Zhang, Y.; Jin, W. J. Halogen Bonding in Room-
Temperature Phosphorescent Materials. Coord. Chem. Rev. 2020, 404,
213107.
(6) Sivchik, V. V.; Solomatina, A. I.; Chen, Y.-T.; Karttunen, A. J.;
Tunik, S. P.; Chou, P.-T.; Koshevoy, I. O. Halogen Bonding to
Amplify Luminescence: A Case Study Using a Platinum Cyclo-
metalated Complex. Angew. Chem., Int. Ed. 2015, 54 (47), 14057−
14060.
(7) Ho, P. S. Halogen Bonding I: Impact on Materials Chemistry
and Life Sciences. Top. Curr. Chem. 2014, 358, 241−276.
(8) Cook, S. A.; Borovik, A. S. Molecular Designs for Controlling the
Local Environments around Metal Ions. Acc. Chem. Res. 2015, 48 (8),
2407−2414.
Daniil M. Ivanov − Institute of Chemistry, Saint Petersburg
State University, Saint Petersburg 199034, Russian
Federation; orcid.org/0000-0002-0855-2251;
Email: d.m.ivanov@spbu.ru
Matti Haukka − Department of Chemistry, University of
Jyväskylä, FI-40014 Jyväskylä, Finland; orcid.org/0000-
0002-6744-7208; Email: matti.o.haukka@jyu.fi
Authors
Margarita Bulatova − Department of Chemistry, University of
Jyväskylä, FI-40014 Jyväskylä, Finland; orcid.org/0000-
0002-1904-5394
J. Mikko Rautiainen − Department of Chemistry, University of
Jyväskylä, FI-40014 Jyväskylä, Finland; orcid.org/0000-
0002-3695-4151
Mikhail A. Kinzhalov − Institute of Chemistry, Saint
Petersburg State University, Saint Petersburg 199034,
Russian Federation; orcid.org/0000-0001-5055-1212
Khai-Nghi Truong − Department of Chemistry, University of
Jyväskylä, FI-40014 Jyväskylä, Finland
Manu Lahtinen − Department of Chemistry, University of
Jyväskylä, FI-40014 Jyväskylä, Finland; orcid.org/0000-
0001-5561-3259
(9) Zapata, F.; González, L.; Caballero, A.; Bastida, A.; Bautista, D.;
Molina, P. Interlocked Supramolecular Polymers Created by
Combination of Halogen- and Hydrogen-Bonding Interactions
through Anion-Template Self-Assembly. J. Am. Chem. Soc. 2018,
140 (6), 2041−2045.
(10) Berger, G.; Soubhye, J.; Meyer, F. Halogen Bonding in Polymer
Science: From Crystal Engineering to Functional Supramolecular
Polymers and Materials. Polym. Chem. 2015, 6 (19), 3559−3580.
(11) Ding, X.; Tuikka, M.; Rissanen, K.; Haukka, M. Extended
Assemblies of Ru(Bpy)(CO)2X2 (X = Cl, Br, I) Molecules Linked by
1,4-Diiodotetrafluoro-Benzene (DITFB) Halogen Bond Donors.
Crystals 2019, 9 (6), 319.
(12) Desiraju, G. R.; Ho, P. S.; Kloo, L.; Legon, A. C.; Marquardt,
R.; Metrangolo, P.; Politzer, P.; Resnati, G.; Rissanen, K. Definition of
the Halogen Bond (IUPAC Recommendations 2013). Pure Appl.
Chem. 2013, 85 (8), 1711−1713.
(13) van Beek, J. A. M.; van Koten, G.; Smeets, W. J. J.; Spek, A. L.
Model for the Initial Stage in the Oxidative Addition of I2 to
Organoplatinum(II) Compounds. X-Ray Structure of Square-
Pyramidal [PtIII{C6H3(CH2NMe2)2-o, o,}(H1-I2)] Containing a
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.inorgchem.1c01591
Author Contributions
M.B. carried out synthesis, crystallizations, part of the SCXRD
studies, part of the wave function calculations, NCI-plot
analysis, ESP visualizations, and manuscript preparation.
D.M.I. carried out a combination of ELF and QTAIM analyses
as well as the ED/ESP minima analysis. Both M.B. and D.M.I.
contributed to data interpretation and analysis. J.M.R. carried
out calculations of wave functions, QTAIM, and LED analysis.
K.-N.T. carried out part of the SCXRD studies. M.L. carried
out PXRD studies of the bulk materials. M.A.K. contributed to
the manuscript preparation and literature search. M.H. guided
the research and experimental design. The manuscript was
I
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
II
2
Linear Pt-I-I Arrangement. J. Am. Chem. Soc. 1986, 108 (16), 5010−
5011.
(Aryl)I···dz [Pt ] Halogen Bonds. Chem. - Eur. J. 2020, 26 (34),
7692−7701.
(14) van Beek, J. A. M.; van Koten, G.; Dekker, G. P. C. M.; Wissing,
E.; Zoutberg, M. C.; Stam, C. H. Synthesis and Reactivity towards
Diiodine of Palladium(II) and Platinum(II) Complexes with Non-
Cyclic and Cyclic Ligands (C6H3{CH2NR1R2}2−2,6)-. End-on
Diiodine-Platinum(II) Bonding in Macrocyclic [PtI(C6H3{CH2NMe-
(CH2)7MeNCH2}-2,6)(η1-I2)]. J. Organomet. Chem. 1990, 394 (1−
3), 659−678.
(29) Yamashina, Y.; Kataoka, Y.; Ura, Y. Inclusion of an Iodine
Molecule in a Tiara-Like Octanuclear Palladium Thiolate Complex.
Eur. J. Inorg. Chem. 2014, 2014 (25), 4073−4078.
(30) Katlenok, E. A.; Rozhkov, A. V.; Levin, O. V.; Haukka, M.;
Kuznetsov, M. L.; Kukushkin, V. Y. Halogen Bonding Involving
Palladium(II) as an XB Acceptor. Cryst. Growth Des. 2021, 21 (2),
1159−1177.
(31) Bikbaeva, Z. M.; Ivanov, D. M.; Novikov, A. S.; Ananyev, I. V.;
Bokach, N. A.; Kukushkin, V. Yu. Electrophilic-Nucleophilic Dualism
of Nickel(II) toward Ni···I Noncovalent Interactions: Semicoordina-
tion of Iodine Centers via Electron Belt and Halogen Bonding via σ-
Hole. Inorg. Chem. 2017, 56 (21), 13562−13578.
(15) Gossage, R. A.; Ryabov, A. D.; Spek, A. L.; Stufkens, D. J.; van
Beek, J. A. M.; van Eldik, R.; van Koten, G. Models for the Initial
Stages of Oxidative Addition. Synthesis, Characterization, and
Mechanistic Investigation of η1-I2 Organometallic “Pincer” Complexes
of Platinum. X-Ray Crystal Structures of [PtI(C6H3{CH2NMe2}2−
1
1
6
2,6)(η -I2)] and Exo-Meso-[Pt(η1-I3)(η -I2)(C H3{CH2N(t-Bu)-
Me}2-2,6)]. J. Am. Chem. Soc. 1999, 121 (11), 2488−2497.
(16) von Chrzanowski, L. S.; Lutz, M.; Spek, A. L.; Suijkerbuijk, B.
M. J. M.; Klein Gebbink, R. J. M. {2,6-Bis[(Dimethyl-amino-
κN)Methyl]-4-{[(2,5-Dioxo-1-Pyrrolidinyl)-oxy]Carbonyl}phenyl-
κC1}(Diiodine)Iodidoplatinum(II) Dichloromethane Hemisolvate.
Acta Crystallogr., Sect. E: Struct. Rep. Online 2007, 63 (5), m1223−
m1225.
(17) Rogachev, A. Yu.; Hoffmann, R. Iodine (I2) as a Janus-Faced
Ligand in Organometallics. J. Am. Chem. Soc. 2013, 135 (8), 3262−
3275.
(18) Freindorf, M.; Yannacone, S.; Oliveira, V.; Verma, N.; Kraka, E.
Halogen Bonding Involving I2 and d8 Transition-Metal Pincer
Complexes. Crystals 2021, 11 (4), 373.
(19) Grove, D. M.; Van Koten, G.; Zoet, R.; Murrall, N. W.; Welch,
A. J. Unique Stable Organometallic Nickel(III) Complexes; Syntheses
and the Molecular Structure of [Ni[C6H3(CH2NMe2)2−2,6]I2]. J.
Am. Chem. Soc. 1983, 105 (5), 1379−1380.
(20) Grove, D. M.; Van Koten, G.; Mul, P.; Zoet, R.; Van der
Linden, J. G. M.; Legters, J.; Schmitz, J. E. J.; Murrall, N. W.; Welch,
A. J. Syntheses and Characterization of Unique Organometallic
Nickel(III) Aryl Species. ESR and Electrochemical Studies and the x-
Ray Molecular Study of Square-Pyramidal [Ni{C6H3(CH2NMe2)2-
o, o’}I2]. Inorg. Chem. 1988, 27 (14), 2466−2473.
(21) Mills, A. M.; van Beek, J. A. M.; Koten, G. v.; Spek, A. L. {2,6-
Bis[(Dimethylamino-κN)Methyl]Phenyl-κC}iodopalladium(II) Bis-
(Diiodine). Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 2002,
58 (5), m304−m306.
(32) Eliseeva, A. A.; Ivanov, D. M.; Rozhkov, A. V.; Ananyev, I. V.;
Frontera, A.; Kukushkin, V. Yu. Bifurcated Halogen Bonding
Involving Two Rhodium(I) Centers as an Integrated σ-Hole
Acceptor. JACS Au 2021, 1 (3), 354−361.
(33) Shaffer, D. W.; Ryken, S. A.; Zarkesh, R. A.; Heyduk, A. F.
Ligand Effects on the Oxidative Addition of Halogens to (dpp-
nacnacR)Rh(phdi). Inorg. Chem. 2012, 51 (22), 12122−12131.
(34) Liau, R.-Y.; Ehlich, H.; Schier, A.; Schmidbaur, H. Bis-
(Triphenylphosphoranylidene)Ammonium Dicyanoaurate(I). Z. Na-
turforsch., B: J. Chem. Sci. 2002, 57 (10), 1085−1089.
(35) Ahrens, B.; Jones, P. G. Polysulfonylamine, CXXVIII [1].
Disulfonylamido-Gold(I)-Komplexe Mit Tetrahydrothiophen Als
Ligand/Polysulfonylamines, CXXVIII. Disulfonylamido-Gold(I)
Complexes with Tetrahydrothiophene as Ligand. Z. Naturforsch., B:
J. Chem. Sci. 2000, 55 (9), 803−813.
(36) Schneider, D.; Schier, A.; Schmidbaur, H. Governing the
Oxidative Addition of Iodine to Gold(i) Complexes by Ligand
Tuning. Dalt. Trans. 2004, No. 13, 1995−2005.
(37) Komoto, Y.; Fujii, S.; Hara, K.; Kiguchi, M. Single Molecular
Bridging of Au Nanogap Using Aryl Halide Molecules. J. Phys. Chem.
C 2013, 117 (46), 24277−24282.
(38) Peng, L.-L.; Huang, B.; Zou, Q.; Hong, Z.-W.; Zheng, J.-F.;
Shao, Y.; Niu, Z.-J.; Zhou, X.-S.; Xie, H.-J.; Chen, W. Low Tunneling
Decay of Iodine-Terminated Alkane Single-Molecule Junctions.
Nanoscale Res. Lett. 2018, 13 (1), 121.
(39) Blakey, I.; Merican, Z.; Rintoul, L.; Chuang, Y.-M.; Jack, K. S.;
Micallef, A. S. Interactions of Iodoperfluorobenzene Compounds with
Gold Nanoparticles. Phys. Chem. Chem. Phys. 2012, 14 (10), 3604−
3611.
(22) Ivanov, D. M.; Novikov, A. S.; Ananyev, I. V.; Kirina, Y. V.;
Kukushkin, V. Y. Halogen Bonding between Metal Centers and
Halocarbons. Chem. Commun. 2016, 52 (32), 5565−5568.
(23) Baykov, S. V.; Dabranskaya, U.; Ivanov, D. M.; Novikov, A. S.;
Boyarskiy, V. P. Pt/Pd and I/Br Isostructural Exchange Provides
Formation of C-I···Pd, C-Br···Pt, and C-Br···Pd Metal-Involving
Halogen Bonding. Cryst. Growth Des. 2018, 18 (10), 5973−5980.
(24) Dabranskaya, U.; Ivanov, D. M.; Novikov, A. S.; Matveychuk, Y.
V.; Bokach, N. A.; Kukushkin, V. Yu. Metal-Involving Bifurcated
Halogen Bonding C-Br···η2(Cl-Pt). Cryst. Growth Des. 2019, 19 (2),
1364−1376.
(40) Dhital, R. N.; Kamonsatikul, C.; Somsook, E.; Sato, Y.; Sakurai,
H. Aryl Iodides as Strong Inhibitors in Gold and Gold-Based
Bimetallic Quasi-Homogeneous Catalysis. Chem. Commun. 2013, 49
(25), 2542−2544.
(41) Maity, P.; Sasai, K.; Dhital, R. N.; Sakai, H.; Hasobe, T.;
Sakurai, H. Excimer Formation of Aryl Iodides Chemisorbed on Gold
Nanoparticles for the Significant Enhancement of Photoluminescence.
J. Phys. Chem. Lett. 2020, 11 (4), 1199−1203.
(42) Stephenson, N. C. The Structure of the Di-Iododi-(o-
Phenylenebisdimethylarsine)-Palladium(II) Molecule. J. Inorg. Nucl.
Chem. 1962, 24 (7), 797−800.
(25) Rozhkov, A. V.; Ivanov, D. M.; Novikov, A. S.; Ananyev, I. V.;
Bokach, N. A.; Kukushkin, V. Y. Metal-Involving Halogen Bond Ar−
II
(43) Bailey, N. A.; Mason, R. Crystal and Molecular Structures of
Two Crystallographic Modifications of Trans-Di-Iodobis-
(Dimethylphenylphosphine)Palladium(II). J. Chem. Soc. A 1968,
No. 0, 2594−2605.
2
I···[dz Pt ] in a Platinum Acetylacetonate Complex. CrystEngComm
2020, 22 (3), 554−563.
(26) Bulatova, M.; Ivanov, D. M.; Haukka, M. Classics Meet
Classics: Theoretical and Experimental Studies of Halogen Bonding in
Adducts of Platinum(II) 1,5-Cyclooctadiene Halide Complexes with
Diiodine, Iodoform, and 1,4-Diiodotetrafluorobenzene. Cryst. Growth
Des. 2021, 21 (2), 974−987.
(44) Blake, A. J.; Li, W.-S.; Lippolis, V.; Parsons, S.; Schröder, M.
Dichloro(μ-[18]aneN2S4)dipalladium(II) Bis(Triiodide)). Acta Crys-
tallogr., Sect. C: Cryst. Struct. Commun. 1998, 54 (10), 1408−1410.
(45) Meij, A. M. M.; Otto, S.; Roodt, A. Synthesis and
Characterisation of Palladium(II) Iodo Complexes Containing
Water Soluble Phosphine Ligands. Crystal Structures of [PdI2(PTA-
H)2][PtI3(PTA)]2·2H2O and Trans-[PdI2(PTA)2]. Inorg. Chim. Acta
2005, 358 (4), 1005−1011.
(27) Zelenkov, L. E.; Eliseeva, A. A.; Baykov, S. V.; Suslonov, V. V.;
Galmés, B.; Frontera, A.; Kukushkin, V. Y.; Ivanov, D. M.; Bokach, N.
A. Electron Belt-to-σ-Hole Switch of Noncovalently Bound Iodine(i)
Atoms in Dithiocarbamate Metal Complexes. Inorg. Chem. Front.
2021, 8, 2505−2517.
(46) Mizuta, T.; Nakayama, K.; Aoki, S.; Miyoshi, K. Interaction
Modes with a Halide Anion of Metal Centers of Edge-Sharing
(28) Katlenok, E. A.; Haukka, M.; Levin, O. V.; Frontera, A.;
Kukushkin, V. Y. Supramolecular Assembly of Metal Complexes by
J
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
Dinuclear Complexes Bearing a Bent Form. Bull. Chem. Soc. Jpn.
2002, 75 (7), 1547−1552.
(47) Doxiadi, E.; Vilar, R.; White, A. J. P.; Williams, D. J. Anion-
Templated Synthesis and Structural Characterisation of Ni/Pd-
Containing Metalla-Macrocycles. Polyhedron 2003, 22 (22), 2991−
2998.
(48) Stephenson, N. C. The Crystal Structure of Di-Iododi-(o-
Phenylenebisdimethylarsine) Platinum(II) Pt(C6H4[As(CH3)2]2)2I2.
J. Inorg. Nucl. Chem. 1962, 24 (7), 791−795.
(49) Contreras, R.; Valderrama, M.; Nettle, A.; Boys, D. Synthesis
and Characterization of New Homo-Heterobinuclear Platinum(II)
Complexes with Dimethylphosphonate as Bridging Ligands. Crystal
Structure of [(η2dppm)Pt{μ-P(O)(OMe)2}2(μ-I)PtMe3]. J. Organo-
met. Chem. 1997, 527 (1−2), 125−132.
(66) Politzer, P.; Lane, P.; Concha, M. C.; Ma, Y.; Murray, J. S. An
Overview of Halogen Bonding. J. Mol. Model. 2007, 13, 305−311.
(67) Politzer, P.; Murray, J. S.; Clark, T. Halogen Bonding: An
Electrostatically-Driven Highly Directional Noncovalent Interaction.
Phys. Chem. Chem. Phys. 2010, 12, 7748−7757.
(68) Contreras-García, J.; Johnson, E. R.; Keinan, S.; Chaudret, R.;
Piquemal, J.-P.; Beratan, D. N.; Yang, W. NCIPLOT: A Program for
Plotting Non-Covalent Interaction Regions. J. Chem. Theory Comput.
2011, 7 (3), 625−632.
(69) Becke, A. D.; Edgecombe, K. E. A Simple Measure of Electron
Localization in Atomic and Molecular Systems. J. Chem. Phys. 1990,
92 (9), 5397−5403.
(70) Bader, R. F. W. Atoms in Molecules: A Quantum Theory;
Clarendon Press, 1990.
(50) Otto, S.; Roodt, A. Five Co-Ordination at Platinum(II) in a
Water Soluble Tertiary Phosphine Complex: Crystal Structure of
[Pt(PTA)3(I)2]·CH3OH. Inorg. Chem. Commun. 2001, 4 (1), 49−52.
(51) Muller, P. Glossary of Terms Used in Physical Organic
Chemistry (IUPAC Recommendations 1994). Pure Appl. Chem. 1994,
66 (5), 1077−1184.
(71) Schneider, W. B.; Bistoni, G.; Sparta, M.; Saitow, M.; Riplinger,
C.; Auer, A. A.; Neese, F. Decomposition of Intermolecular
Interaction Energies within the Local Pair Natural Orbital Coupled
Cluster Framework. J. Chem. Theory Comput. 2016, 12 (10), 4778−
4792.
(72) Aakeröy, C. B.; Baldrighi, M.; Desper, J.; Metrangolo, P.;
Resnati, G. Supramolecular Hierarchy among Halogen-Bond Donors.
Chem. - Eur. J. 2013, 19 (48), 16240−16247.
(73) Aakeroy, C. B.; Wijethunga, T. K.; Desper, J. Practical Crystal
Engineering Using Halogen Bonding: A Hierarchy Based on
Calculated Molecular Electrostatic Potential Surfaces. J. Mol. Struct.
2014, 1072, 20−27.
(74) Oliveira, V.; Cremer, D. Transition from Metal-Ligand Bonding
to Halogen Bonding Involving a Metal as Halogen Acceptor a Study
of Cu, Ag, Au, Pt, and Hg Complexes. Chem. Phys. Lett. 2017, 681,
56−63.
(75) Ramasubbu, N.; Parthasarathy, R.; Murray-Rust, P. Angular
Preferences of Intermolecular Forces around Halogen Centers:
Preferred Directions of Approach of Electrophiles and Nucleophiles
around Carbon-Halogen Bond. J. Am. Chem. Soc. 1986, 108 (15),
4308−4314.
(76) Cox, S. R.; Williams, D. E. Representation of the Molecular
Electrostatic Potential by a Net Atomic Charge Model. J. Comput.
Chem. 1981, 2 (3), 304−323.
(52) Zheng, Q.; Borsley, S.; Nichol, G. S.; Duarte, F.; Cockroft, S. L.
The Energetic Significance of Metallophilic Interactions. Angew.
Chem., Int. Ed. 2019, 58 (36), 12617−12623.
(53) Bulatova, M.; Melekhova, A. A.; Novikov, A. S.; Ivanov, D. M.;
Bokach, N. A. Redox Reactive (RNC)CuII Species Stabilized in the
Solid State via Halogen Bond with I2. Z. Kristallogr. - Cryst. Mater.
2018, 233 (6), 371−377.
(54) Buldakov, A. V.; Kinzhalov, M. A.; Kryukova, M. A.; Ivanov, D.
M.; Novikov, A. S.; Smirnov, A. S.; Starova, G. L.; Bokach, N. A.;
Kukushkin, V. Y. Isomorphous Series of PdII-Containing Halogen-
Bond Donors Exhibiting Cl/Br/I Triple Halogen Isostructural
Exchange. Cryst. Growth Des. 2020, 20 (3), 1975−1984.
(55) Terraneo, G.; Resnati, G.; Metrangolo, P. Iodine and Halogen
Bonding. In Iodine Chemistry and Applications; Kaiho, T., Ed.; Wiley
Online Books; 2014; pp 159−194.
(56) Lau, K. Y.; Mayr, A.; Cheung, K.-K. Synthesis of Transition
Metal Isocyanide Complexes Containing Hydrogen Bonding Sites in
Peripheral Locations. Inorg. Chim. Acta 1999, 285 (2), 223−232.
(57) Kashina, M. V.; Kinzhalov, M. A.; Smirnov, A. S.; Ivanov, D.
M.; Novikov, A. S.; Kukushkin, V. Y. Dihalomethanes as Bent
Bifunctional XB/XB-Donating Building Blocks for Construction of
Metal-Involving Halogen Bonded Hexagons. Chem. - Asian J. 2019, 14
(21), 3915−3920.
̌
̌
(77) Kolár, M.; Hostas, J.; Hobza, P. The Strength and
Directionality of a Halogen Bond Are Co-Determined by the
Magnitude and Size of the σ-Hole. Phys. Chem. Chem. Phys. 2014,
16, 9987−9996.
(78) Bader, R. F. W.; Carroll, M. T.; Cheeseman, J. R.; Chang, C.
Properties of Atoms in Molecules: Atomic Volumes. J. Am. Chem. Soc.
1987, 109 (26), 7968−7979.
(58) Crociani, B.; Boschi, T.; Belluco, U. Synthesis and Reactivity of
Novel Palladium(II)-Isocyanide Complexes. Inorg. Chem. 1970, 9 (9),
2021−2025.
(59) Kaharu, T.; Tanaka, T.; Sawada, M.; Takahashi, S. Liquid-
Crystalline Palladium- and Platinum-Isonitrile Complexes: Synthesis,
Mesomorphic Properties and Molecular Structure. J. Mater. Chem.
1994, 4 (6), 859−865.
̌
(79) Kolár, M. H.; Hobza, P. Computer Modeling of Halogen Bonds
and Other σ-Hole Interactions. Chem. Rev. 2016, 116 (9), 5155−
5187.
(80) Rozhkov, A. V.; Eliseeva, A. A.; Baykov, S. V.; Galmés, B.;
Frontera, A.; Kukushkin, V. Y. One-Pot Route to X-Perfluoroarenes
(X = Br, I) Based on FeIII-Assisted C-F Functionalization and
Utilization of These Arenes as Building Blocks for Crystal Engineering
Involving Halogen Bonding. Cryst. Growth Des. 2020, 20 (9), 5908−
5921.
(81) Lane, J. R.; Contreras-Garcia, J.; Piquemal, J.-P.; Miller, B. J.;
Kjaergaard, H. G. Are Bond Critical Points Really Critical for
Hydrogen Bonding? J. Chem. Theory Comput. 2013, 9 (8), 3263−
3266.
(82) Lefebvre, C.; Rubez, G.; Khartabil, H.; Boisson, J.-C.;
Contreras-García, J.; Hénon, E. Accurately Extracting the Signature
of Intermolecular Interactions Present in the NCI Plot of the Reduced
Density Gradient versus Electron Density. Phys. Chem. Chem. Phys.
2017, 19 (27), 17928−17936.
(83) Triguero, S.; Llusar, R.; Polo, V.; Fourmigué, M. Halogen
Bonding Interactions of Sym-Triiodotrifluorobenzene with Halide
Anions: A Combined Structural and Theoretical Study. Cryst. Growth
Des. 2008, 8 (7), 2241−2247.
(60) Kinzhalov, M. A.; Luzyanin, K. V.; Boyarskaya, I. A.; Starova, G.
L.; Boyarskiy, V. P. Synthetic and Structural Investigation of
[PdBr2(CNR)2] (R = Cy, Xyl). J. Mol. Struct. 2014, 1068, 222−227.
(61) Rigamonti, L.; Forni, A.; Manassero, M.; Manassero, C.; Pasini,
A. Cooperation between Cis and Trans Influences in cis-PtII(PPh3)2
Complexes: Structural, Spectroscopic, and Computational Studies.
Inorg. Chem. 2010, 49 (1), 123−135.
́
(62) Troff, R. W.; Mäkelä, T.; Topic, F.; Valkonen, A.; Raatikainen,
K.; Rissanen, K. Alternative Motifs for Halogen Bonding. Eur. J. Org.
Chem. 2013, 2013, 1617−1637.
(63) Bondi, A. Van Der Waals Volumes and Radii. J. Phys. Chem.
1964, 68 (3), 441−451.
(64) Novikov, A. S.; Ivanov, D. M.; Avdontceva, M. S.; Kukushkin,
V. Y. Diiodomethane as a Halogen Bond Donor toward Metal-Bound
Halides. CrystEngComm 2017, 19 (18), 2517−2525.
(65) Bertolotti, F.; Shishkina, A. V.; Forni, A.; Gervasio, G.; Stash, A.
I.; Tsirelson, V. G. Intermolecular Bonding Features in Solid Iodine.
Cryst. Growth Des. 2014, 14 (7), 3587−3595.
K
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX

Inorganic Chemistry
pubs.acs.org/IC
Article
(84) Cauliez, P.; Polo, V.; Roisnel, T.; Llusar, R.; Fourmigué, M.
The Thiocyanate Anion as a Polydentate Halogen Bond Acceptor.
CrystEngComm 2010, 12, 558−566.
Complexes and Study of Their Stability in Isomerization and Ligand
Disproportionation Reactions. Russ. J. Gen. Chem. 2018, 88 (6),
1180−1187.
(102) Altun, A.; Saitow, M.; Neese, F.; Bistoni, G. Local Energy
Decomposition of Open-Shell Molecular Systems in the Domain-
Based Local Pair Natural Orbital Coupled Cluster Framework. J.
Chem. Theory Comput. 2019, 15 (3), 1616−1632.
(85) Juárez-Pérez, E. J.; Aragoni, M. C.; Arca, M.; Blake, A. J.;
́
̃
Devillanova, F. A.; Garau, A.; Isaia, F.; Lippolis, V.; Nunez, R.; Pintus,
A.; Wilson, C. A Unique Case of Oxidative Addition of Interhalogens
IX (X = Cl, Br) to Organodiselone Ligands: Nature of the Chemical
Bonding in Asymmetric I-Se-X Polarised Hypervalent Systems. Chem.
- Eur. J. 2011, 17 (41), 11497−11514.
(103) Riplinger, C.; Neese, F. An Efficient and near Linear Scaling
Pair Natural Orbital Based Local Coupled Cluster Method. J. Chem.
Phys. 2013, 138 (3), 034106.
(86) Xu, L.; Sang, P.; Zou, J.-W.; Xu, M.-B.; Li, X.-M.; Yu, Q.-S.
Evaluation of Nucleotide C-Br···O-P Contacts from ONIOM
Calculations: Theoretical Insight into Halogen Bonding in Nucleic
Acids. Chem. Phys. Lett. 2011, 509 (4), 175−180.
(87) Bartashevich, E. V.; Matveychuk, Y. V.; Troitskaya, E. A.;
Tsirelson, V. G. Characterizing the Multiple Non-Covalent Inter-
actions in N, S-Heterocycles-Diiodine Complexes with Focus on
Halogen Bonding. Comput. Theor. Chem. 2014, 1037, 53−62.
(88) Bartashevich, E.; Yushina, I.; Kropotina, K.; Muhitdinova, S.;
Tsirelson, V. Testing the Tools for Revealing and Characterizing the
Iodine{–}iodine Halogen Bond in Crystals. Acta Crystallogr., Sect. B:
Struct. Sci., Cryst. Eng. Mater. 2017, 73 (2), 217−226.
(104) Riplinger, C.; Sandhoefer, B.; Hansen, A.; Neese, F. Natural
Triple Excitations in Local Coupled Cluster Calculations with Pair
Natural Orbitals. J. Chem. Phys. 2013, 139 (13), 134101.
(105) Riplinger, C.; Pinski, P.; Becker, U.; Valeev, E. F.; Neese, F.
Sparse MapsA Systematic Infrastructure for Reduced-Scaling
Electronic Structure Methods. II. Linear Scaling Domain Based Pair
Natural Orbital Coupled Cluster Theory. J. Chem. Phys. 2016, 144
(2), 024109.
(106) Weigend, F.; Ahlrichs, R. Balanced Basis Sets of Split Valence,
Triple Zeta Valence and Quadruple Zeta Valence Quality for H to Rn:
Design and Assessment of Accuracy. Phys. Chem. Chem. Phys. 2005, 7,
3297−3305.
(107) Hellweg, A.; Hättig, C.; Höfener, S.; Klopper, W. Optimized
Accurate Auxiliary Basis Sets for RI-MP2 and RI-CC2 Calculations for
the Atoms Rb to Rn. Theor. Chem. Acc. 2007, 117 (4), 587−597.
(108) Zhao, Y.; Truhlar, D. G. A New Local Density Functional for
Main-Group Thermochemistry, Transition Metal Bonding, Thermo-
chemical Kinetics, and Noncovalent Interactions. J. Chem. Phys. 2006,
125 (19), 194101.
(109) Dunlap, B. I. Robust and Variational Fitting: Removing the
Four-Center Integrals from Center Stage in Quantum Chemistry. J.
Mol. Struct.: THEOCHEM 2000, 529 (1), 37−40.
(110) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Petersson,
G. A.; Nakatsuji, H.; Li, X.; Caricato, M.; Marenich, A. V.; Bloino, J.;
Janesko, B. G.; Gomperts, R.; Mennucci, B.; Hratchian, H. P.; Ortiz, J.
V.; Izmaylov, A. F.; Sonnenberg, J. L.; Williams-Young, D.; Ding, F.;
Lipparini, F.; Egidi, F.; Goings, J.; Peng, B.; Petrone, A.; Henderson,
T.; Ranasinghe, D.; Zakrzewski, V. G.; Gao, J.; Rega, N.; Zheng, G.;
Liang, W.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.;
Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.;
Throssell, K.; Montgomery, J. A., Jr.; Peralta, J. E.; Ogliaro, F.;
Bearpark, M.; Heyd, J. J.; Brothers, E. N.; Kudin, K. N.; Staroverov, V.
N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant,
J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Millam, J. M.; Klene, M.;
Adamo, C.; Cammi, R.; Ochterski, J. W.; Martin, R. L.; Morokuma,
K.; Farkas, O.; Foresman, J. B.; Fox, D. J. Gaussian 16, revision C.01;
Gaussian, Inc.: Wallingford CT, 2016.
(89) Yushina, I. D.; Kolesov, B. A. Interplay of Intra- and
Intermolecular Interactions in Solid Iodine at Low Temperatures:
Experimental and Theoretic Spectroscopy Study. J. Phys. Chem. A
2019, 123 (21), 4575−4580.
(90) Silvi, B.; Savin, A. Classification of Chemical Bonds Based on
Topological Analysis of Electron Localization Functions. Nature
1994, 371 (6499), 683−686.
(91) Savin, A.; Nesper, R.; Wengert, S.; Fässler, T. F. ELF: The
Electron Localization Function. Angew. Chem., Int. Ed. Engl. 1997, 36
(17), 1808−1832.
(92) Fuentealba, P.; Chamorro, E.; Santos, J. C. Understanding and
Using the Electron Localization Function. Theor. Comput. Chem.
2007, 19, 57−85.
(93) Suslonov, V. V.; Eliseeva, A. A.; Novikov, A. S.; Ivanov, D. M.;
Dubovtsev, A. Y.; Bokach, N. A.; Kukushkin, V. Y.
Tetrachloroplatinate(Ii) Anion as a Square-Planar Tecton for Crystal
Engineering Involving Halogen Bonding. CrystEngComm 2020, 22
(24), 4180−4189.
(94) Mata, I.; Molins, E.; Alkorta, I.; Espinosa, E. Topological
Properties of the Electrostatic Potential in Weak and Moderate N···H
Hydrogen Bonds. J. Phys. Chem. A 2007, 111 (28), 6425−6433.
(95) Lamberts, K.; Handels, P.; Englert, U.; Aubert, E.; Espinosa, E.
Stabilization of Polyiodide Chains via Anion···anion Interactions:
Experiment and Theory. CrystEngComm 2016, 18 (21), 3832−3841.
(96) Bartashevich, E.; Mukhitdinova, S.; Yushina, I.; Tsirelson, V.
Electronic Criterion for Categorizing the Chalcogen and Halogen
Bonds: Sulfur{–}iodine Interactions in Crystals. Acta Crystallogr., Sect.
B: Struct. Sci., Cryst. Eng. Mater. 2019, 75 (2), 117−126.
(97) Bartashevich, E.; Matveychuk, Y.; Tsirelson, V. Identification of
the Tetrel Bonds between Halide Anions and Carbon Atom of Methyl
Groups Using Electronic Criterion. Molecules 2019, 24 (6), 1083.
(98) Harvey, P. D.; Truong, K. D.; Aye, K. T.; Drouin, M.;
Bandrauk, A. D. Resonance-Enhanced Intraligand and Metal-Metal
Raman Modes in Weakly Metal-Metal-Interacting Platinum(II)
Complexes and Long-Range Relationship between Metal-Metal
Separations and Force Constants. Inorg. Chem. 1994, 33 (11),
2347−2354.
(111) Otero-de-la-Roza, A.; Johnson, E. R.; Luana, V. Critic2: A
̃
Program for Real-Space Analysis of Quantum Chemical Interactions
in Solids. Comput. Phys. Commun. 2014, 185 (3), 1007−1018.
(112) Williams, T.; Kelley, C. Gnuplot 4.4: An Interactive Plotting
Program, 2010.
(113) Humphrey, W.; Dalke, A.; Schulten, K. VMD: Visual
Molecular Dynamics. J. Mol. Graphics 1996, 14 (1), 33−38.
(114) Keith, T. A. AIMALL, version 12.06.03; TK Gristmill
Software: Overland Park, KS, 2003.
(115) Lu, T.; Chen, F. Multiwfn: A Multifunctional Wavefunction
Analyzer. J. Comput. Chem. 2012, 33 (5), 580−592.
(116) Neese, F. Software Update: The ORCA Program System,
Version 4.0. Wiley Interdiscip. Rev.: Comput. Mol. Sci. 2018, 8 (1),
No. e1327.
(99) Sluch, I. M.; Miranda, A. J.; Slaughter, L. M. Channeled
Polymorphs of cis-M(CNPh)2Cl2 (M = Pt, Pd) with Extended
Metallophilic Interactions. Cryst. Growth Des. 2009, 9 (3), 1267−
1270.
(117) Weigend, F. Hartree-Fock Exchange Fitting Basis Sets for H to
Rn †. J. Comput. Chem. 2008, 29 (2), 167−175.
(100) Sluch, I. M.; Miranda, A. J.; Elbjeirami, O.; Omary, M. A.;
Slaughter, L. M. Interplay of Metallophilic Interactions, π-π Stacking,
and Ligand Substituent Effects in the Structures and Luminescence
Properties of Neutral PtII and PdII Aryl Isocyanide Complexes. Inorg.
Chem. 2012, 51 (20), 10728−10746.
(101) Kinzhalov, M. A.; Kashina, M. V.; Mikherdov, A. S.; Katkova,
S. A.; Suslonov, V. V. Synthesis of Platinum(II) Phoshine Isocyanide
L
https://doi.org/10.1021/acs.inorgchem.1c01591
Inorg. Chem. XXXX, XXX, XXX−XXX