Jan 29, 2017 - All the non-hydrogen atoms were refined ... contains 9 such complex molecules, and all of them have the similar molecular geometry [Fig 2].
Accepted Manuscript Synthesis, structural characterization, crystal structure and theoretical study of a Pd(II)-salen complex with propylene linkage Mohammad Azam, Saud I. Al-Resayes, Saied M. Soliman, Agata Trzesowska Kruszynska, Rafal Kruszynski PII:
S0022-2860(17)30139-4
DOI:
10.1016/j.molstruc.2017.02.007
Reference:
MOLSTR 23401
To appear in:
Journal of Molecular Structure
Received Date: 19 November 2016 Revised Date:
29 January 2017
Accepted Date: 1 February 2017
Please cite this article as: M. Azam, S.I. Al-Resayes, S.M. Soliman, A.T. Kruszynska, R. Kruszynski, Synthesis, structural characterization, crystal structure and theoretical study of a Pd(II)-salen complex with propylene linkage, Journal of Molecular Structure (2017), doi: 10.1016/j.molstruc.2017.02.007. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Synthesis, structural characterization, crystal structure and theoretical study of a Pd(II)-salen complex with propylene linkage
Mohammad Azam1*, Saud I Al-Resayes1, Saied M. Soliman2,3, Agata Trzesowska-Kruszynska4, Rafal Kruszynski4 1
Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, KSA Department of Chemistry, Rabigh College of Science and Art, King Abdulaziz University, P.O. Box 344, Rabigh 21911, Saudi Arabia 3 Department of Chemistry, Faculty of Science, Alexandria University, P. O. Box 426, Ibrahimia, 21321 Alexandria, Egypt. 4 Institute of General and Ecological Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
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For Correspondence: Email: azam_res@yahoo.com Tel & Fax: +966-1-4675982
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Abstract A Pd(II)-salen complex derived from salen ligand is reported. The reported complex is 13
C-NMR and
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investigated by microanalyses (C, H, N), ESI-MS spectrometry, FT-IR, 1H- and
UV/Vis spectroscopic studies. In addition, crystal structure measurement study has also been carried out in order to confirm the structure of Pd(II)-salen complex.
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In order to explore the insights into the structural bonding of the studied complex, computational measurements has been carried out. Combined topology and NBO studies were made to explore
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the nature of Pd-O and Pd-N bonding in the complex. The natural charges showed that the transfers of the negative charge from the ligand to palladium atom is at 1.4157–1.4312 e. Atom in a molecule (AIM) analysis showed the electron density (ρ(r) ˃ 0.1) and its Laplacian (ߘ ଶ ρ(r) ˃ 0). These topological parameters showed that covalent bonding interactions are dominant in Pd-
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N and Pd-O bonds. However, Pd-N bonds have more covalent characters than Pd-O bonds, which is further confirmed by the ratio of local electron potential energy density to the local electron kinetic energy density (|V(r)|/G(r)) found to be higher for Pd-N bonds (1.1683-1.1993)
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as compared to Pd-O bonds (1.0689-1.0926). AIM and NBO reveal that shorter Pd-N and Pd-O bonds have higher interaction energies (Eint) and hence higher bond covalence.
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Key words: Pd(II)-salen complex; Structural characterization; DFT measurements
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Introduction Salen ligands have been of significant attention due to their straightforward, simple and cheap synthesis in bulk amount [1]. Furthermore, the salen complexes are known for several years due
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to their simple structures with mostly single points of attachment, and interests in diverse areas of research [2], especially in catalysis, biochemistry and radiopharmaceutical industries for cancer targeting cells [3-8]. Recently, complexes of salen ligands have been used in preparation
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of coordination polymers exhibiting luminescent properties and hydrogen storage [9, 10]. Interestingly, metal centers of most of the studied salen complexes belong to the first transition
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series. Unfortunately, complexes based on second and third transition metal series have not been given much attention [11]. Salen ligand based palladium complexes have been used in various catalytic reactions, and in making number of anticancer drugs [11, 12]. However, the use of Pd(II) and its complexes in medicine is not much explored because of their rapid hydrolysis than
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their corresponding platinum counterparts [12, 13].
Over the years, we have been interested in studying salen ligand, derived from the condensation between
2-hydroxybenzaldehyde
and
2,2-dimethyl-1,3-diaminopropane
[14],
and
its
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complexation with various metal ions [15]. Herein we are reporting the synthesis of a novel Pd(II)-salen complex and its various spectroscopic studies and crystal structure. Furthermore, to
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obtain insights into the bonding of the studied complex, DFT calculations have been made. Experimental
General methods and Instrumentation All reagents and solvents used were of highest purity and obtained from Sigma-Aldrich Chemical Co. Salen ligand was synthesized following the reported protocol [14]. The preparation of Pd(II)-salen complex was carried out in Schlenk line tube in inert atmosphere. The ElementarVarrio EL analyzer was used in recoding C,H,N analyses. FT-IR and NMR spectra 3
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were collected using Perkin Elmer 621 spectrophotometer and JEOL 400 spectrometer in CDCl3, respectively. The electronic spectrum was determined on Pharmacia LKB-Biochem, UV–vis
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spectrophotometer at room temperature.
Crystal structure determination
X-ray diffraction were collected on Bruker APEXII automatic diffractometer with graphite
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monochromated CuKα (λ = 1.54178Å) radiation at temperature 100.0(1) K, by ω scan technique. The crystal data are presented in Table 1, and selected bond lengths and bond angles are given in
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Table 2. The intermolecular interactions are given in Table 3 [16]. All the non-hydrogen atoms were refined anisotropically using full-matrix, least-squares mode on F2. The XS, XL and XTL [17] software was used for all the calculations. The usage of the MoKα radiation for measurement of the crystals of complex leads to absence of the observable reflections beyond the
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θ= 18° (mainly due to extremely unfavourable crystal shapes, i.e. extremely thin, almost two dimensional plates), what is unacceptable in unambiguous determination of crystal structure. Thus, the CuKα microsource was used during collection of diffraction data. Such alteration of the
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experimental conditions, allows collection of the observable data beyond the θ resulting from
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minimal required resolution, unfortunately the crystal shape still affects the data, and applied corrections does not resolved the problem, as the large set of data was still unobservable in several directions. This affects the displacement ellipsoids, cause the prolation and oblation effects among some of them. The one of the asymmetric unit complex molecules (containing the Pd61 atom) shows two positional disorder (with almost equal participation of both domains) in the region of the central linkage (i.e. the (CH3)2C(CH2)2 moiety).
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Synthesis of Pd(II)-salen complex
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To a stirred dichloromethane solution of salen ligand (50 mg, 0.161 mol) [14] was added solution of [Pd(CH3CN)2Cl2] (42 mg, 0.161 mol) dissolved in dichloromethane [Scheme 1]. After stirring for 1h, the volume of the reaction mixture was reduced to 1 ml. We added 10 ml of
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hexane in the reaction mixture resulting into the formation of a precipitate, which was separated out and washed with diethyl ether to make it analytically pure. This colored precipitate on
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recrystallization in the mixture of dichloromethane and acetonitrile (1:3) yielded orange colored crystals in few days.
Yield 85%, color: orange, mp 185 0C; Molecular Formula C19H20N2O2Pd; Molecular Weight, 414.79; Anal. Calc.: C, 55.02; H, 4.86; N, 6.75 Found: C, 55.07; H, 4.92; N, 6.81 %. 1H-NMR
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(CDCl3): (ppm) 8.33 (s, -CH=N), 6.87–7.47 (m, Ph-H), 3.48 (s, 4H, -CH2), 1.10 (s, 6H, -CH3); C-NMR (CDCl3): (ppm) 165.1 (-CH=N); IR (KBr cm-1): 1600 ν(-CH=N); ESI-MS: (M+1) m/z
415.7
N
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N
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13
OH HO
50 mg; 0.161 mol Salen ligand
Dichloromethane [PdCl2(CH3CN)2]
Stirring
N N Pd O O
42 mg; 0.161 mol Pd(II)-salen complex
Pd(II) salt
Scheme 1: Synthesis of Pd(II)-salen complex
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Theoretical calculations The single crystal input cartesian coordinates used for the geometry optimization of the studied Pd(II)-salen complex were collected from the CIF file of the complex. All calculations were
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performed using the built in B3LYP method in Gaussian 03 program package [18]. The basis sets used are 6-31G(d,p) for the nonmetal atoms (C, H, N and O) [19], and lanl2dz for Pd atoms [20]. The optimization followed by frequency calculations gave no imaginary frequency modes
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at the calculated geometry. Moreover, single point calculations on the nine complex units found in the crystal structure were used to provide the wave function, analyzed by NBO [21] and
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QTAIM [22] methods, by NBO3 [23] and Multwfn [24,25] technique, respectively. Results and Discussion
Pd(II)-salen complex was obtained by the reaction of [PdCl2(CH3CN)2] with salen ligand [14] in 1:1 M ratio in dichloromethane. The isolated compound was a crystalline material and stable at
Crystal Structure
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room temperature.
A perspective view of Pd(II)-salen complex structure is shown in Figure 1. The asymmetric unit
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contains 9 such complex molecules, and all of them have the similar molecular geometry [Fig 2]. It is in difference to the ethanol solvate of complex [26], which contains the two complex
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molecules in the asymmetric unit. All atoms occupy the general positions, however the molecules possess the pseudosymmetry mirror planes going through the Pdx1 and Cx9 atoms (where x = {1,2,3,...,9}). Consequently the respect pairs of analogous atoms of each molecule are related by non-crystallographic, above mentioned, pseudosymmetry element. The palladium atom is four-coordinated by two imine nitrogen atoms, and two alkoxide oxygen atoms. The coordination environment of the metal atoms adopts slightly distorted square planar geometry
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and the central Pd ions lie almost within the least squares planes calculated through the N2O2 moieties. The salicylidene-1-methaneaminato moieties are almost planar, similarly to the conformation of pure ligand [14] ethanol solvate of reported complex [26]. The mutual
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arrangement of the salicylidene-1-methaneaminato moieties in different molecules of asymmetric unit varies, and the dihedral angle between the all non-hydrogen atoms of these moieties of specific molecule lies in range 4.5(0.7) — 23.2(3)º. This is different from the range
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observed for ethanol solvate of Pd(II) complex [26], which is 8.0 — 17.1º
The crystal net of studied complex does not contain the classical hydrogen bonds, as a result of
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absence of the strong and medium strength hydrogen bond donors. The weak C—H•••O intramolecular hydrogen bonds [27] (Table 3) provide some linkage between the complex
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molecules.
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Fig 1. The molecular structure of one of Pd(II)-salen complex molecules, plotted with 50% probability of displacement ellipsoids of non-hydrogen atoms. The hydrogen atoms are draw as spheres of arbitrary radii. The last grapheme of atom label is identical for chemically the same atoms in all molecules.
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Fig 2. The molecules of asymmetric unit. The hydrogen and disordered atoms are omitted for clarity. Spectroscopic studies
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The azomethine vibration at 1623 cm−1 in the ligand [14] undergoes negative shift and appears at 1600 cm−1 in the complex [28]. Furthermore, the characteristic band due to ν(Ar–OH) at 3384 cm−1 in free ligand [14] disappears due to deprotonation in the Pd(II)-salen complex [29]. Moreover, ν(Ar–O) vibrations at 1205 cm−1 in the ligand shows negative shift upon complexation to Pd(II) ion, and appears at 1195 cm−1 [15,29], which is further confirmed by the presence of
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ν(Ar-O-Pd) vibration
at 1322 cm-1,suggesting its coordination to Pd(II) ion via the phenoxy
hydroxyl group [30] [Supplementary Information Fig S1]. The –OH resonances at 13.54 ppm in the ligand [14] disappears in the complex, suggesting the
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formation of Pd–O bond due to deprotonation. A sharp singlet at 8.32 ppm due to azomethine proton in ligand is shifted downfield in Pd(II)-salen complex and appears at 8.33 ppm, confirms that azomethine nitrogen is linked to the palladium ion. The phenyl ring protons observed at
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6.87–7.25 ppm in the ligand undergoes small shifts and appear at 6.87-7.47 in the complex. Furthermore, resonances due to –CH3 and –CH2 protons at 1.06 ppm and 3.48 ppm, respectively
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in the ligand show small shift upon coordination to Pd(II) ion, suggesting ligand is coordinated to Pd(II) ion [Supplementary Information Fig S2]. The
13
C-NMR spectrum shows number of carbon signals ascribed to various aliphatic and
aromatic carbons. The sharp signals due to Ar-C-OH and azomethine carbons in the free ligand
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[14] appear at 165.7 and 161.5 ppm, respectively. Furthermore, the signals due to phenyl ring carbon appear at 116.9–132.2 ppm in the ligand. Moreover, the quaternary carbon, –CH2, and – CH3 carbons appear at 68.1 ppm, 36.2 ppm and 24.3 ppm, respectively in the free ligand. These
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values show deshielding upon coordination to palladium ion in the complex [Supplementary Information Fig. S3].
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The molecular ion peak (M+1) of Pd(II)-salen complex corresponding to it molecular formula C19H20N2O2Pd appears at m/z 415.7. Furthermore, the complex also shows number of peaks corresponding to its various fragments, and the relative intensities of these peaks give an idea of the stability of these fragments. The other prominent peaks are at m/z 394.2 and 408.2 [Supplementary Information Fig S4].
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Theoretical studies The crystal unit of the studied Pd(II)-salen complex showed wide variations of Pd-N and Pd-O
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distances. AIM and NBO studies are useful in studying the nature and strength of bonding in molecular systems of the complex. For the nine different Pd(II)-salen complex units in the crystal lattice, DFT single point calculations were recorded at B3LYP level (6-31G(d,p) for C, H,
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N, O and lanl2dz for Pd) to analyze the different Pd-N and Pd-O bonds in these complex units. The partial charges calculated using NBO method on the Pd, N and O atoms are given in Table
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4. The negative charge transferred from the ligand to palladium atom lie at 1.4157–1.4312 e. However, both the Pd-N and the Pd-O bonds are not equivalents in each complex unit, indicating some distortion in the geometry of Pd(II)-salen complex. As a result, negative charge transfer from the ligand to the Pd-atom is not the same in all complex units.
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Topology analyses of the nine complex units were used to describe the nature of Pd-N and Pd-O bonding interactions in these complex units. We omitted one complex unit due to the presence of structure disorder which could affect the accuracy of results so only 8 units will be discussed in
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this section. The electron density (ρ(r)), its Laplacian (ߘ ଶ ρ(r)), the total energy density H(r), and the ratio of local electron potential energy density to the local electron kinetic energy density
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(|V(r)|/G(r)) at the bond critical point (BCP: the point on the bond path at which density has its minimal value) are important properties in description of the bonding nature [Table 5]. Bader and Essen observed that the shared (covalent) interactions have high electron density at the BCP (ρ(r)˃10-1 a.u) while its values are small (ρ(r) ≈10-2) for the ionic systems and other closed shell interactions [31]. It is obvious that the values of ρ(r) are ˃ 0.1 for all Pd-N and most of Pd-O bonds in eight complex units indicate the covalent bonding interactions are dominant in these
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cases. Figure 3 showed the inverse relation between Pd-N and Pd-O distances with the electron density at the BCPs for the eight complex units. For Pd-O bonds, there is small region (blue circle) with ρ(r) very slightly less than 10-1 a.u. Those have the highest ionic character among
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Pd-O bonds. In general, Pd-N bonds have greater range of covalent character than Pd-O bonds which indicate that the larger the Pd-N or Pd-O distance, the lower the covalent character of the bond. Moreover, the Laplacian of the electron density ߘ ଶ ρ(r) < 0 for covalent bonding while for
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closed-shell bonding such as ionic systems the ߘ ଶ ρ(r) > 0 [32]. The latter is valid for the second row elements while for longer bonds, the Laplacian of the electron density (ߘ ଶ ρ(r)) tends to be
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positive.
The total energy density is negative for covalent bonding and positive for closed-shell interactions. Furthermore, all the Pd-N and Pd-O BCPs have negative H(r) value. Also, the ratio |V(r)|/G(r) is more than 2 for typically covalent interactions [33]. In general, the |V(r)|/G(r) > 1
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indicate covalent bonding, while |V(r)|/G(r) < 1 indicate predominantly closed-shell interactions. The ratio |V(r)|/G(r) is more than 1 for the Pd-N and Pd-O BCPs which agree with the more covalent characters of the Pd-N bonds than Pd-O ones. The |V(r)|/G(r) of Pd-N bonds are at
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1.1683 - 1.1993 while less (1.0689-1.0926) for the Pd-O ones. The interaction energies at the PdN and Pd-O BCP are calculated according the relation Eint=V(r)/2 [34] which is considered as
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measure of the bond strength. The results shown in Table 5 are presented graphically in Figure 4. This Figure revealed the fact that the shorter the Pd-N/Pd-O bonds, the higher the interaction between two atoms forming the bond and hence more bond covalence.
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units.
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Fig 3. The electron density ρ(r) versus Pd-N and Pd-O bond distances for the different complex
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70.0 Pd-N
Pd-O
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60.0
55.0
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Eint (KJ/mol)
65.0
45.0 1.9
2.0
2.0
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50.0
2.0
2.0
2.0
2.1
Bond distances (Å)
70.0
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60.0
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Eint (KJ/mol)
65.0
55.0
Pd-O
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Pd-N
50.0
45.0 0.094
0.099
0.104
0.109
0.114
0.119
0.124
0.129
ρ(r)
Fig 4. Graphical representation of the interaction energies Eint versus bond distances (upper) and electron density ρ(r) (lower) for all Pd-N and Pd-O bonds of 8 complex units. 14
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The nature of orbitals included in the Pd-N and Pd-O bonds in one of the complex units were analyzed using second order perturbation theory calculated in the framework of NBO theory [Table 6].
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From the first glance, the nature of the donor→acceptor interactions is almost the same in both Pd-N bonds but they differ very quietly in their interaction energies. The net E(2) sum for the short Pd-N1 (171.34 kcal/mol) is higher than that for the longer one Pd-N2 (162.64 kcal/mol).
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The natural orbital interaction responsible for the Pd-N bonding are LP(1)N→ LP*(5)Pd/ LP*(6)Pd interactions [Fig. 5]. We noted that both the Pd-O bonds differ in the number and
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nature of NBOi → NBOj interactions. The slightly shorter Pd-O2 bond is included in larger number of NBOi → NBOj than the longer one. The Pd-O1 (2.008Å) bond is mainly due to the interaction between the third lone pair of O-atom (LP(3)O) to the empty orbital (LP*(5)Pd) of the Pd-atom with E(2) value of 79.35 kcal/mol. The second Pd-O2 bond arises mainly due to
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LP(2)O→ LP*(5)Pd with 69.1 kcal/mol. The net interaction energies for the Pd-O1 (197.56 kcal/mol) and Pd-O2 (196.07 kcal/mol) are almost similar [Fig. 5]. The analysis of the Pdorbitals indicated that the dxy atomic orbital is the main orbital included in the Pd-O bonds with
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significant contributions from the Pd s-orbital for the for Pd-N bonds.
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LP*(5)Pd (mainely dxy ˃92%)
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LP*(6)Pd (mainely s-orbital ˃81%)
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LP(1)N1+LP(1)N2
LP(3)O1+LP(2)O2
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Fig. 5. The O and N lone pair(s) orbitals (lower) and the Pd unfilled valence nonbonding orbitals (upper) included in the Pd-O and Pd-N interactions
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Geometry The structure of the studied Pd(II)-salen complex was optimized using B3LYP method (basis sets are: 6-31G(d,p) for C, H, N and O and lanl2dz for Pd). Figure 6 and Table S1
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(Supplementary information) showed comparison between the calculated and experimental geometry. The Pd-N and Pd-O bond lengths appeared at 1.954-2.008 Å and 1.970-2.010 Å in Pd(II)-salen complex which are quite close to the calculated values at 2.055 and 2.019Å,
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respectively. Furthermore, Both the Pd-N as well as Pd-O bonds were predicted to be equivalent due to non-involvement of intermolecular interactions and the symmetric structure of the ligand
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in the calculations. Moreover, molecular orbitals have great importance in the description of reactivity, ability to electronic excitation and biological studies. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are the most important among MOs as they describe the ability of molecule to lose and gain electron. The calculated
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HOMO and LUMO energies of Pd(II)-salen complex are -5.0818 eV and -1.5715 eV, and their pictures are given in Figure 7. At the optimized geometry, the HOMO has mainly dz2 nature and concentrated over the Pd(II) ion while LUMO is distributed over the π-system of the organic
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ligand.
The HOMO→LUMO excitation displays the lowest energy electronic transition of Pd(II)-salen
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complex. The calculated HOMO-LUMO energy gap is 3.5103 eV in the complex. The absorption study of 1.0 x 10-4 molar solution of Pd(II)-salen complex in dichloromethane at 200-600 nm shows a square planar geometry with three spin allowed d-d- transitions [Supplementary Information Fig S5] [35,36]. The absorption band at 392 nm (ε = 4.5 ×105 M−1 cm−1) (3.1629 eV) is attributed to metal-to ligand charge transfer transitions [37,38] and agree very well with the calculated value.
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Fig. 6. The optimized geometry of the studied Pd-complex (left) and overlay between the experimental and calculated structures (right).
Fig. 7. The highest occupied (left) and lowest unoccupied (right) molecular orbitals of the studied Pd(II)-salen complex.
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NMR
The GIAO technique was implemented in calculating chemical shifts in nuclear magnetic resonance [39, 40] in gas phase, and in solution of the studied complex in chloroform in order to
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simulate the calculated 1H-NMR chemical shifts with those obtained experimentally. The effect of solvent on the NMR chemical shifts was computed using solvent environment of the Polarizable Continuum Model (PCM) [41, 42]. Furthermore, the relative chemical shifts were
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calculated using corresponding TMS shielding, calculated at the same theoretical level as the reference [Table 7]. Furthermore, the calculated chemical shifts are almost the same as obtained
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from the experimental NMR chemical shifts, and point out that the solvent exerts very little effect on the NMR chemical shifts [Fig 8]. Furthermore, Figure 8 points out the correlation coefficients (R2) of the 1H- and
13
C-NMR chemical shifts are 0.9923 and 0.9938, respectively
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indicating the incredibly well correlation between the calculated and experimental results.
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Fig. 8. Straight line correlations between the calculated and experimental 1H-NMR (upper) and 13 C-NMR (lower) chemical shifts of the studied Pd-complex in chloroform.
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Conclusions
It has been reported that salen ligand, H2L [14] has been used to form Pd(II)-salen complex with square planar geometry. Insights into the bonding of the Pd(II)-salen complex have been
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explored by DFT. The calculated bond parameters of the Pd(II)-salen complex are in incredibly good correlation with their experimental results. The studies NBO analysis clearly points out the nature of Pd-N and Pd-O bond.
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Supplementary Data:
Tables of crystal data and structure refinement, anisotropic displacement coefficients, atomic
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coordinates and equivalent isotropic displacement parameters for non-hydrogen atoms, H-atom coordinates and isotropic displacement parameters, bond lengths and interbond angles have been deposited with the Cambridge Crystallographic Data Centre under No. CCDC1429291. Acknowledgements:
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The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at king Saud University for funding this work through Research Group number RG -
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1436-003.
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References
1. Y. Heo, Y.Y. Kang, T. Palani, J. Lee, S. Lee, Inorg. Chem. Commun. 23 (2012) 1
3. P.G. Cozzi, Chem. Soc. Rev. 33 (2004) 410
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2. N.T.S. Phan, D.H. Brown, H. Adams, S.E. Spey, P. Styring, Dalton Trans. 2004, 1448
4. X. Zheng, C.W. Jones, M. Weck, J. Am. Chem. Soc. 129 (2007) 1105
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5. K.C. Gupta, A.K. Sutar, Coord. Chem. Rev. 252 (2008) 1420
6. M.S. Taylor, D.N. Zalatan, A.M. Lerchner, E.N. Jacobsen, J. Am. Chem. Soc. 127 (2005) 1313
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7. S.E. Schaus, B.D. Brandes, J.F. Larrow, M. Tokunaga, K.B. Hansen, A.E. Gould, M.E. Furrow, E.N. Jacobsen, J. Am. Chem. Soc. 124 (2002) 1307
8. K. Ansari, J. Grant, S. Kasiri, G. Woldemariam, B. Shrestha, S. Mandal, J. Inorg. Biochem. 103 (2009) 818
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9. T. Gao, P.-F. Yan, G.-M. Li, G.-F. Hou, J.-S. Gao, Polyhedron 26 (2007) 5382 10. A. Bhunia, P.W. Roesky, Y. Lan, G.E. Kostakis, A.K. Powell, Inorg. Chem. 48 (2009) 10483
(2010) 4096
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11. J. Fonseca, J. Martinez, L.C.-Silva, A.L. Magales, M.T. Duarte, C. Freire, Inorg. Chim. Acta 363
12. M. Galanski, V. B. Arion, M.A. Jakupec, B.K. Keppler, Current Pharmaceutical Design, 9
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(2003) 2078
13. A. Garoufis, S.K. Hadjikakou, N. Hadjiliadis, Coord. Chem. Rev. 253 (2009) 1384 14. J.P. Corden, W. Errington, P. Moore, M.G.H. Wallbridge, Act Cryst C52 (1996) 125 15. (a) M. Azam, S. Dwivedi, S.I. Al-Resayes, S.F. Adil, M.S. Islam, A.T.- Kruszynska, R. Kruszynski, D.-U. Lee, J. Mol. Str. 1130 (2017) 122; (b) M. Azam, G. Velmurugan, S.M. Wabaidur,
A.T.-Kruszynska,
R.
Kruszynski,
22
S.I.
Al-Resayes,
Z.A.
Al-Othman,
P.
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Venuvanalingam, Sci. Rep. 6 (2016) 1; (c) M. Azam, S.I. Al-Resayes, G. Velmurugan, P. Venuvanalingam, J. Wagler, Edwin Kroke, Dalton Trans. 44 (2015) 568
17. G.M. Sheldrick, ActaCrystallogr. A64 (2008) 112
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16. Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
18. Gaussian 03, Revision C.01, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K.N. Kudin, J. C. Burant, J. M.
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Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida,
M AN U
T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, P.Y. Ayala, K. Morokuma, G.A. Voth, P. Salvador, J.J. Dannenberg, V.G. Zakrzewski, S. Dapprich, A.D. Daniels, M.C. Strain, O. Farkas, D.K. Malick,
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A. D. Rabuck, K. Raghavachari, J.B. Foresman, J.V. Ortiz, Q. Cui, A.G. Baboul, S. Clifford, J. Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, M. Challacombe, P.M. W. Gill, B.
EP
Johnson, W. Chen, M.W. Wong, C. Gonzalez, J.A. Pople, Gaussian, Inc., Wallingford CT, 2004. 19. V. A. Rassolov, M.A. Ratner, J.A. Pople, P. C. Redfern, L.A. Curtiss, “6-31G* Basis Set for
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Third-Row Atoms ” J. Comp. Chem., 22 (2001) 976 20. (a) T.H. Dunning Jr. and P.J. Hay, in Modern Theoretical Chemistry, Ed. H. F. Schaefer III, Vol. 3 (Plenum, New York, 1977) 1; (b) P.J. Hay and W. R. Wadt, “Ab initio effective core potentials for molecular calculations-potentials for the transition-metal atoms Sc to Hg,” J. Chem. Phys., 82 (1985) 270; (c) W. R. Wadt and P. J. Hay, “Ab initio effective core potentials for
23
ACCEPTED MANUSCRIPT
molecular calculations-potentials for main group elements Na to Bi,” J. Chem. Phys. 82 (1985) 284 21. E.D. Glendening, C.R. Landis, F. Weinhold, J. Comp. Chem. 34 (2013) 1429
1990
RI PT
22. R.F.W. Bader, Atoms in Molecules: A Quantum Theory, Oxford University Press, Oxford, U.K.,
Version 3.1,
CI, University of Wisconsin, Madison, 1998
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23. NBO Version 3.1, E. D. Glendening, A. E. Reed, J. E. Carpenter, and F. Weinhold, NBO
(2012) 580
M AN U
24. Tian Lu, Feiwu Chen, Multiwfn: A Multifunctional Wavefunction Analyzer, J. Comp. Chem. 33
25. (a) E. Espinosa, I. Alkorta, J. Elguero, E. Molins, J. Chem. Phys. 117 (2002) 5529;(b) D. Cremer, E. Kraka, Croat. Chem. Acta 57 (1984) 1259
26. W.N.W. Ibrahim, M. Shamsuddin, S. Chantrapromma; H.-K. Fun; Acta Crystallogr. Sect. E:
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Struct. Rep.Online, 64 (2008) m909
27. G.R. Desiraju, T. Steiner, The Weak Hydrogen Bond in Structural Chemistry and Biology, Oxford University Press, Oxford, 1999
EP
28. (a) S.S. Sreejith, N. Mohan, N. Aiswarya, M.R.P. Kurup, Polyhedron 115 (2016) 180; (b) J. Fonseca, J. Martinez, L.C.-Silva, A.L. Magalhães, M.T. Duarte, C. Freire, Inorg. Chim. Acta 363
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(2010) 4096; (c) M. Shakir, N. Shahid, N. Sami, M. Azam, A.U. Khan, Spectrochim. Acta Part A 82 (2011) 31
29. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, Wiley, New York, 1986
30. (a) G.A. Kohawole and K. S. Patel, J. Chem. Soc., Dalton Trans. 1981, 1241; (b) V. Selvarani, B. Annaraj, M.A. Neelakantan, S. Sundaramoorthy, D. Velmurugan, Polyhedron 54 (2013) 74
24
ACCEPTED MANUSCRIPT
31. R. F. W. Bader and H. Essen, J. Chem. Phys. 80 (1984) 1943 32. R.F.W. Bader, Atoms in Molecules: A Quantum Theory, Oxford University Press, Oxford, U.K., 1990
RI PT
33. (a) E. Espinosa, I. Alkorta, J. Elguero, E. Molins, J. Chem. Phys. 117 (2002) 5529; (b) D. Cremer, E. Kraka, Croat. Chem. Acta 57 (1984) 1259
34. E. Espinosa, E. Molins, C. Lecomte, Chem. Phys. Lett. 285 (1998) 170
Platinum Complexes, Pergamon Press, Oxford, 1973
SC
35. S.E. Livingstone, The Chemistry of Ruthenium, Rhodium, Palladium, Osmium, Iridium and
M AN U
36. H. H. Jaffe and M. Orchin, Theory and Applications of Ultraviolet Spectroscopy,J. Wiley, New York, 1962
37. A.B.P. Lever, Inorganic Electronic Spectroscopy, Elsevier, New York, 1984 38. M. Ulusoy, O. Birel, O. Sahin, O. Buyukgungor and B. Cetinkya, Polyhedron 38 (2012) 141
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39. R. Ditchfield, J. Chem. Phys. 56 (1972) 5688
40. K. Wolinski, J.F. Hinton, P. Pulay, J. Am. Chem. Soc. 112 (1990) 8251 41. A. D. Becke, Phys. Rev. A 38 (1988) 3098
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42. W. Wang, W.J. Mortier, J. Am. Chem. Soc. 108 (1986) 5708
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Table 1. Crystal and structure refinement data of Pd(II) salen complex Pd(II) complex Empirical formula
C19H20N2O2Pd 414.77
Crystal system, space group
monoclinic, Cc (No.9)
Unit cell dimensions [Å, °]
a = 21.2928(10)
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Formula weight
b = 40.8895(19) c = 18.1287(9)
Volume [Å3]
15758.6(13) 3
Z, Calculated density [Mg/m ]
36, 1.573 7560
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F(000)
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β = 93.237(8)
Crystal size [mm]
0.092, 0.090, 0.001
θ range for data collection [°]
3.30 to 72.62
Index ranges
-25≤h≤26, -50≤k≤50, -22≤1≤22
Reflections collected / unique
80143 / 25121 [R(int) = 0.0409] 96.7 (to θ = 67°)
Data / restraints / parameters
25121 / 2$ / 1990
Goodness-of-fit on F2 Final R indices [I>2σ(I)] R indices (all data)
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Completeness [%]
1.086
R1 = 0.0390, wR2 = 0.0994 R1 = 0.0393, wR2 = 0.0996
-3
Largest diff. peak and hole [e•Å ] $
0.764, -1.869
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Floating origin restraints
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1.993(8) 2.009(8) 2.015(9) 2.037(9) 1.225(16) 1.479(11) 1.461(15) 1.255(17) 1.964(10) 1.999(7) 2.003(8) 2.007(8) 1.331(16) 1.463(13) 1.453(15) 1.379(13) 1.975(7) 1.976(7) 2.011(9) 2.052(8) 1.304(13) 1.458(12) 1.484(12) 1.299(15) 1.999(7) 2.001(10) 2.010(8) 2.032(9) 1.272(15) 1.453(15) 1.465(15) 1.264(16) 1.970(8) 1.979(10) 1.990(8) 2.011(8) 1.356(13) 1.468(12) 1.312(16) 1.973(11) 1.981(7) 1.991(7) 2.023(8) 1.266(17) 1.50(2) 1.55(2) 1.483(13) 1.286(13) 1.976(8) 1.981(7)
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Pd(II)-salen complex Pd11—O11 Pd11—O12 Pd11—N12 Pd11—N11 C17—N11 N11—C18 C1C—N12 N12—C1D Pd21—N22 Pd21—O22 Pd21—O21 Pd21—N21 C27—N21 N21—C28 C2C—N22 N22—C2D Pd31—O31 Pd31—O32 Pd31—N32 Pd31—N31 C37—N31 N31—C38 C3C—N32 N32—C3D Pd41—O42 Pd41—N41 Pd41—O41 Pd41—N42 C47—N41 N41—C48 C4C—N42 N42—C4D Pd51—O52 Pd51—N51 Pd51—O51 Pd51—N52 C57—N51 C5C—N52 N52—C5D Pd61—N61 Pd61—O61 Pd61—O62 Pd61—N62 C67—N61 N61—C68A N61—C68B C6C—N62 N62—C6D Pd71—O71 Pd71—O72
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Table 2. Selected distances between atoms of Pd(II)-salen complex [Å].
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2.013(11) 2.013(9) 1.318(15) 1.474(13) 1.481(12) 1.315(15) 1.985(7) 1.997(7) 2.004(10) 2.051(10) 1.240(15) 1.472(15) 1.492(12) 1.211(17) 1.955(9) 2.003(7) 2.008(8) 2.007(7) 1.284(14) 1.471(12) 1.317(13) 1.454(12)
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Pd71—N71 Pd71—N72 C77—N71 N71—C78 C7C—N72 N72—C7D Pd81—O82 Pd81—O81 Pd81—N81 Pd81—N82 C87—N81 N81—C88 C8C—N82 N82—C8D Pd91—N91 Pd91—O92 Pd91—N92 Pd91—O91 C97—N91 N91—C98 N92—C9D N92—C9C
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Table 3. Hydrogen bonds geometry of Pd(II) salen complex [Å, °]. ____________________________________________________________________________
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D—H•••A d(D-H) d(H•••A)
