The theoretical data for the half‐lantern complexes {Pt(CN^
)(μ‐SN^
)}2 1–3; CN^
is cyclometalated 2‐Ph‐benzothiazole; SN^
is 2‐SH‐pyridine (1), 2‐SH‐benzoxazole (2), 2‐SH‐tetrafluorobenzothiazole ...(3) indicate that the Pt⋅⋅⋅Pt orbital interaction increases the nucleophilicity of the outer dz2
orbitals to provide assembly with electrophilic species. Complexes 1–3 were co‐crystallized with bifunctional halogen bonding (XB) donors to give adducts (1–3)2⋅(1,4‐diiodotetrafluorobenzene) and infinite polymeric 1⋅1,1′‐diiodoperfluorodiphenyln. X‐ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I⋅⋅⋅dz2
PtII XBs between iodine σ‐holes and lone pairs of the positively charged (PtII)2 centers acting as nucleophilic sites. The polymer includes a curved linear chain ⋅⋅⋅Pt2⋅⋅⋅I(areneF)I⋅⋅⋅Pt2⋅⋅⋅ involving XB between iodine atoms of the perfluoroarene linkers and (PtII)2 moieties. The 195Pt NMR, UV/Vis, and CV studies indicate that XB is preserved in CH(D)2Cl2 solutions.
Shedding light: Half‐lantern dz2PtII2 complexes in which the PtII2 center exhibits increased nucleophilicity of the outer orbitals were assembled with symmetric diiodoperfluoroarene halogen bonding (XB) donors to give extended supramolecular arrays formed through (Aryl)I⋅⋅⋅dz2PtII XB, which were studied by XRD and by extensive theoretical calculations. Cyclic voltammetric, 195Pt NMR, and UV/Vis studies provided evidence that the XB is preserved in solution.
The nucleophilic addition of 3-(4-cyanopyridin-2-yl)-1,1-dimethylurea (1) to cis-Pt(CNXyl)2Cl2 (2) gave a new cyclometallated compound 3. It was characterized by NMR spectroscopy (1H, 13C, 195Pt) and ...high-resolution mass spectrometry, as well as crystallized to obtain two crystalline forms (3 and 3·2MeCN), whose structures were determined by X-ray diffraction. In the crystalline structure of 3, two conformers (3A and 3B) were identified, while the structure 3·2MeCN had only one conformer 3A. The conformers differed by orientation of the N,N-dimethylcarbamoyl moiety relative to the metallacycle plane. In both crystals 3 and 3·2MeCN, the molecules of the Pt(II) complex are associated into supramolecular dimers, either {3A}2 or {3B}2, via stacking interactions between the planes of two metal centers, which are additionally supported by hydrogen bonding. The theoretical consideration, utilizing a number of computational approaches, demonstrates that the C···dz2(Pt) interaction makes a significant contribution in the total stacking forces in the geometrically optimized dimer 3A2 and reveals the dz2(Pt)→π*(PyCN) charge transfer (CT). The presence of such CT process allowed for marking the C···Pt contact as a new example of a rare studied phenomenon, namely, tetrel bonding, in which the metal site acts as a Lewis base (an acceptor of noncovalent interaction).
2,3,5,6-Tetramethyl-1,4-diisocyanobenzene (1), 1,4-diisocyanobenzene (2), and 1,4-dicyanobenzene (3) were co-crystallized with 1,3,5-triiodotrifluorobenzene (1,3,5-FIB) to give three cocrystals, ...1·1,3,5-FIB, 2·2(1,3,5-FIB), and 3·2(1,3,5-FIB), which were studied by X-ray diffraction. A common feature of the three structures is the presence of I···Cisocyanide or I···Nnitrile halogen bonds (HaBs), which occurs between an iodine σ-hole and the isocyanide C-(or the nitrile N-) atom. The diisocyanide and dinitrile cocrystals 2·2(1,3,5-FIB) and 3·2(1,3,5-FIB) are isostructural, thus providing a basis for accurate comparison of the two types of noncovalent linkages of C≡N/N≡C groups in the composition of structurally similar entities and in one crystal environment. The bonding situation was studied by a set of theoretical methods. Diisocyanides are more nucleophilic than the dinitrile and they exhibit stronger binding to 1,3,5-FIB. In all structures, the HaBs are mostly determined by the electrostatic interactions, but the dispersion and induction components also provide a noticeable contribution and make the HaBs attractive. Charge transfer has a small contribution (<5%) to the HaB and it is higher for the diisocyanide than for the dinitrile systems. At the same time, diisocyanide and dinitrile structures exhibit typical electron-donor and π-acceptor properties in relation to the HaB donor.
Structures of three tetrahalophthalic anhydrides (TXPA: halogen = Cl (TCPA), Br (TBPA), I (TIPA)) were studied by X-ray diffraction, and several types of halogen bonds (HaB) and lone pair···π-hole ...(lp···πh) contacts were revealed in their structures. HaBs involving the central oxygen atom of anhydride group (further X···O(anhydride) were recognized in the structures of TCPA and TBPA. In contrast, for the O(anhydride) atom of TIPA, only interactions with the π system (π-hole) of the anhydride ring (further lp(O)···πh) were observed. Computational studies by a number of theoretical methods (molecular electrostatic potentials, the quantum theory of atoms in molecules, the independent gradient model, natural bond orbital analyses, the electron density difference, and symmetry-adapted perturbation theory) demonstrated that the X···O(anhydride) contacts in TCPA and TBPA and lp(O)···πh in TIPA are caused by the packing effect. The supramolecular architecture of isostructural TCPA and TBPA was mainly affected by X···O(acyl) and X···X HaBs, and, for TIPA, the main contribution provided I···I HaBs.
The nucleophilic addition of 3-(4-cyanopyridin-2-yl)-1,1-dimethylurea (1) to cis-Pt(CNXyl)sub.2Clsub.2 (2) gave a new cyclometallated compound 3. It was characterized by NMR spectroscopy (sup.1H, ...sup.13C, sup.195Pt) and high-resolution mass spectrometry, as well as crystallized to obtain two crystalline forms (3 and 3·2MeCN), whose structures were determined by X-ray diffraction. In the crystalline structure of 3, two conformers (3A and 3B) were identified, while the structure 3·2MeCN had only one conformer 3A. The conformers differed by orientation of the N,N-dimethylcarbamoyl moiety relative to the metallacycle plane. In both crystals 3 and 3·2MeCN, the molecules of the Pt(II) complex are associated into supramolecular dimers, either {3A}sub.2 or {3B}sub.2, via stacking interactions between the planes of two metal centers, which are additionally supported by hydrogen bonding. The theoretical consideration, utilizing a number of computational approaches, demonstrates that the C···dzsup.2(Pt) interaction makes a significant contribution in the total stacking forces in the geometrically optimized dimer 3Asub.2 and reveals the dsub.z sup.2(Pt)→π*(PyCN) charge transfer (CT). The presence of such CT process allowed for marking the C···Pt contact as a new example of a rare studied phenomenon, namely, tetrel bonding, in which the metal site acts as a Lewis base (an acceptor of noncovalent interaction).
Abstract
The theoretical data for the half‐lantern complexes {Pt(
)(μ‐
)}
2
1
–
3
;
is cyclometalated 2‐Ph‐benzothiazole;
is 2‐SH‐pyridine (
1
), 2‐SH‐benzoxazole (
2
), ...2‐SH‐tetrafluorobenzothiazole (
3
) indicate that the Pt
⋅⋅⋅
Pt orbital interaction increases the nucleophilicity of the outer d
orbitals to provide assembly with electrophilic species. Complexes
1
–
3
were co‐crystallized with bifunctional halogen bonding (XB) donors to give adducts (
1
–
3
)
2
⋅
(1,4‐diiodotetrafluorobenzene) and infinite polymeric
1⋅
1,1′‐diiodoperfluorodiphenyl
n
. X‐ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I
⋅⋅⋅
d
Pt
II
XBs between iodine σ‐holes and lone pairs of the positively charged (Pt
II
)
2
centers acting as nucleophilic sites. The polymer includes a curved linear chain
⋅⋅⋅
Pt
2
⋅⋅⋅
I(arene
F
)I
⋅⋅⋅
Pt
2
⋅⋅⋅
involving XB between iodine atoms of the perfluoroarene linkers and (Pt
II
)
2
moieties. The
195
Pt NMR, UV/Vis, and CV studies indicate that XB is preserved in CH(D)
2
Cl
2
solutions.
The nucleophilic addition of 3-(4-cyanopyridin-2-yl)-1,1-dimethylurea (
) to
-Pt(CNXyl)
Cl
(
) gave a new cyclometallated compound
. It was characterized by NMR spectroscopy (
H,
C,
Pt) and ...high-resolution mass spectrometry, as well as crystallized to obtain two crystalline forms (
and
·2MeCN), whose structures were determined by X-ray diffraction. In the crystalline structure of
, two conformers (
and
) were identified, while the structure
·2MeCN had only one conformer
. The conformers differed by orientation of the
,
-dimethylcarbamoyl moiety relative to the metallacycle plane. In both crystals
and
·2MeCN, the molecules of the Pt(II) complex are associated into supramolecular dimers, either {
}
or {
}
, via stacking interactions between the planes of two metal centers, which are additionally supported by hydrogen bonding. The theoretical consideration, utilizing a number of computational approaches, demonstrates that the C···
(Pt) interaction makes a significant contribution in the total stacking forces in the geometrically optimized dimer
and reveals the
(Pt)→π*(PyCN) charge transfer (CT). The presence of such CT process allowed for marking the C···Pt contact as a new example of a rare studied phenomenon, namely, tetrel bonding, in which the metal site acts as a Lewis base (an acceptor of noncovalent interaction).
The theoretical data for the half-lantern complexes {Pt(
)(μ-
)}
1-3;
is cyclometalated 2-Ph-benzothiazole;
is 2-SH-pyridine (1), 2-SH-benzoxazole (2), 2-SH-tetrafluorobenzothiazole (3) indicate ...that the Pt⋅⋅⋅Pt orbital interaction increases the nucleophilicity of the outer d
orbitals to provide assembly with electrophilic species. Complexes 1-3 were co-crystallized with bifunctional halogen bonding (XB) donors to give adducts (1-3)
⋅(1,4-diiodotetrafluorobenzene) and infinite polymeric 1⋅1,1'-diiodoperfluorodiphenyl
. X-ray crystallography revealed that the supramolecular assembly is achieved through (Aryl)I⋅⋅⋅d
Pt
XBs between iodine σ-holes and lone pairs of the positively charged (Pt
)
centers acting as nucleophilic sites. The polymer includes a curved linear chain ⋅⋅⋅Pt
⋅⋅⋅I(arene
)I⋅⋅⋅Pt
⋅⋅⋅ involving XB between iodine atoms of the perfluoroarene linkers and (Pt
)
moieties. The
Pt NMR, UV/Vis, and CV studies indicate that XB is preserved in CH(D)
Cl
solutions.
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