Supramolecular bimetallic vanadium(V) complex driven by hydrogen bonding and O???O chalcogen bonding interaction: Oxidation of cyclohexane and its application toward C[sbnd]H bond activation

Article abstract of DOI:10.1016/j.ica.2020.119837

Vanadium(V) complex was synthesized in good yield and characterized by FT-IR, UV–Visible and NMR spectroscopy. The structure of the complex was confirmed by single X-ray crystallography. X-ray structural analysis the complex featuring O???O chalcogen bonding interaction and other short interaction. The O???O intermolecular interactions distance is 2.794 ?. Clearly, the O???O intermolecular distance in the O-linked complex is less than the sum of van der Waals atomic radii of oxygen 3.00 ? (r_vdW (O) = 1.50 ?). Oxidations of cyclohexane to cyclohexanol were also carried out, using the synthetic complex as a catalyst. The catalytic studies were carried out successfully using m-chloroperbenzoic acid as oxidant at 100 °C, under solvents free conditions. The catalytic protocols are very simple and the catalyst can be recovered without any lost in products formation in the next consecutive cycle.

Full text of DOI:10.1016/j.ica.2020.119837

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Research paper
Supramolecular bimetallic vanadium(V) complex driven by hydrogen bond‐
ing and O∙∙∙O chalcogen bonding interaction: Oxidation of cyclohexane and
its application toward C-H bond activation
Sunshine Dominic Kurbah, Ndege Simisi Clovis
PII:
DOI:
Reference:
S0020-1693(20)31036-7
https://doi.org/10.1016/j.ica.2020.119837
ICA 119837
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Inorganica Chimica Acta
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12 May 2020
12 June 2020
12 June 2020
Please cite this article as: S.D. Kurbah, N.S. Clovis, Supramolecular bimetallic vanadium(V) complex driven by
hydrogen bonding and O∙∙∙O chalcogen bonding interaction: Oxidation of cyclohexane and its application toward
C-H bond activation, Inorganica Chimica Acta (2020), doi: https://doi.org/10.1016/j.ica.2020.119837
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Supramolecular bimetallic vanadium(V) complex driven by hydrogen
bonding and O∙∙∙O chalcogen bonding interaction: Oxidation of
cyclohexane and its application toward C-H bond activation
a*
b
Sunshine Dominic Kurbah and Ndege Simisi Clovis
aDepartment of Chemistry, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Eraligool-
88723, Karimganj, Assam, India
7
bSchool of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India
Abstract
Vanadium(V) complex was synthesized in good yield and characterized by FT-IR, UV-
Visible and NMR spectroscopy. The structure of the complex was confirmed by single X-ray
crystallography. X-ray structural analysis the complex featuring O∙∙∙O chalcogen bonding
interaction and other short interaction. The O∙∙∙O intermolecular interactions distance is 2.794
Å. Clearly, the O∙∙∙O intermolecular distance in the O-linked complex is less than the sum of
van der Waals atomic radii of oxygen 3.00 Å (rvdW (O) = 1.50 Å). Oxidations of cyclohexane
to cyclohexanol were also carried out, using the synthetic complex as a catalyst. The catalytic
o
studies were carried out successfully using m-chloroperbenzoic acid as oxidant at 100 C,
under solvents free conditions. The catalytic protocols are very simple and the catalyst can be
recovered without any lost in products formation in the next consecutive cycle.
Introduction
Hydrocarbons, especially those containing saturated hydrocarbons are the main constituents
of natural gas and oil, which are the main feedstock for chemical industry [1-4]. Hence,
chemical transformations of these materials to more valuable oxygenated products such as
alcohols, ketones, acids, and peroxides is a demanding goal both in catalysis, industries as
well as in the field of research in contemporary chemistry [5-8]. Activating C-H bonds of
cyclohexane by oxidation to produce cyclohexanol, and cyclohexanone that are important
industrial raw materials for the production of adipic acid, and caprolactam which in turn can
be used in manufacturing of nylon-6,6 and nylon-6 [9-13]. In view of economic and
environmental important, and the need to search for more active, efficient and selective
catalysts for such oxidation reactions that can operate under sustainable conditions is
challenging.

In many cases, the used of noble metal catalysts such as zirconium, ruthenium,
rhodium, and iridium complexes were usually used as catalysts for C-H bond activation [14-
2
3]. However, the used of these novel metals find many drawbacks and limited services
because of their expensive, environmental pollution and catalyst life. Hence, in order to
reduce their usage, some non-noble transitional metals are required. In particular, vanadium
complexes are well known as an attractive class of catalysts for oxidation of cyclohexane [24-
2
8]. However, many vanadium complexes catalyzed the oxidation of cyclohexane in presence
of hydrogen peroxide and acid promoter. Hanson and co-workers reported, vanadium
complex of the composition (HQ) VO(OiPr) (HQ = 8-quinolinate) catalyzed the oxidation of
cyclohexane to cyclohexanol using nitric acid as promoter in presence of hydrogen peroxide
2
[
29]. Pombeiro and co-workers, synthesis three alkali heterobimetallic vanadium(V)
v
coordination polymers (V /M (M = Na, K, Cs) bearing bis(salicylaldehyde)-
oxaloyldihydrazone ligand and applying them in oxidation catalysis, for oxidation of
cyclohexane [30]. Therefore, few reports are known to exist for aerobic oxidation of
cyclohexane under mild conditions using vanadium catalyst.
Scheme 1. Schematic diagram showing the preparation of ligand (H LG)
4
In this article, we report the synthesis, full characterization, structural features and aerobic
oxidations of cyclohexane using newly synthesized vanadium complexes. The reactions were
carried out under simple conditions using mCPBA as an oxidant. Moreover, the catalyst can
be prepared in air using commercially available reagents, making the overall process
inexpensive, simple, and accessible without using any dry box or Schlenk techniques. Hence,
in this work we aim to develop a simple catalytic system which can be used for green
oxidation processes in organic chemistry.
Experimental section
Materials and methods
Solvents were reagent grade and used as received. Bis(2-hydroxy-1-naphthaldehyde)-
glutaroyldihydrazone (H LG) was prepared in good yield as shown in Scheme 1. Other
4

chemicals such as vanadium pentoxide, hydrazine hydrate, m-chloroperbenzoic acid,
salicylaldehyde, sodium carbonate, diethyl glutarate, were E-Merck, Himedia, and equivalent
grades. C, H and N were determined by microanalytical method using a Perkin-Elmer 2400
CHNS/O Analyzer 11. Infrared spectra were recorded as KBr discs using Perkin Elmer BX-
-1
1
13
III/FTIR Spectrophotometer (4000 - 200 cm ). The H NMR and C NMR spectra were
recorded on AMX-400 MHz and 100 MHz in DMSO-d solution using TMS as internal
6
standard. Solution electronic spectra were recorded on a Perkin-Elmer Lambda-25
spectrophotometer.
X-ray crystallography Diffraction
Crystallographic data for the complex were recorded using Xcalibur, Eos, Gemini
diffractometer equipped with a monochromated Mo K radiation ((λ = 0.71073 Å) source. For
data collection and reduction CrysAlis PRO; Agilent, 2013 software packages were used.
Semi empirical absorption based on multiscan was used with the help of SADABS software
[
[
-
31]. SHELXT-2014 and SHELXL-2014 was used for structure solutions and refinements
2
2
32]. Refinement based on F procedure minimizing R = Σ || F
o
| - |F
c
||
/
Σ |F
o
|, wR = [Σ [w (F
o
2
- F
2)2/ (n - p)]1/2 were applied. All non-hydrogen atoms
F
c
2)2] / Σ (F
o
2)2]1/2 and S = [Σ [(F
o
c
were refined anisotropically, whereas the hydrogen atom positions were isotropically refined
in the final refinement.
Synthesis of hydrazone ligand (H LG)
4
A solution of 2-hydroxy-1-naphthaldehyde (0.34 g, 2 mmol) in ethanol (5 mL) was added to
a stirred solution of glutaroyldihydrazide (0.16 g, 1 mmol) in ethanol (2 mL) at room
temperature, resulting in an immediate color change from white to light yellow. The solvent
o
volume was reduced to approximately 5 mL and the sample stirred at 40 C for 30 minute,
resulting in formation of a yellow crystalline solid that was collected by filtration, washed
with aqueous ethanol (2 mL), and dried under vacuum. Yield: 74%. Anal. found %: C,
1
6
9.18; H, 5.14; N, 11.91. Calculated % for C27
NMR (DMSO-d , 400 MHz): δ
aromatic), 2.05-3.35 (m, 6H, CH
H
24
N
4
O
4
: C, 69.22; H, 5.16; N, 11.96. H
6
H
10.77 (s, 2H, OH), 9.78 (s, 2H, NH), 7.96-7.06 (m, 12H,
2
).
Synthesis of VO LG
2
A solution of hydrazone ligand (0.47 g, 1 mmol) in methanol (5 mL) was added to a stirred
solution of aqueous vanadium pentoxide (0.2 g, 1 mmol) at room temperature, the resulting

o
mixtures were heated to 70 C for 1 hr. The reaction mixtures were cooled to room
temperature and followed by addition of sodium carbonate (0.11 g, 1 mmol) under stirring
condition for 30 min, filtered, washed with methanol and dried to obtain a brown colour
solid. Single crystal was obtained successfully by slow evaporation of the solvents at room
temperature. Anal. found %: C, 51.39; H, 3.17; N, 8.84. Calculated %: C, 51.45; H, 3.20; N,
-
1
8
1
2
1
.89. FT-IR bands (KBr pellets, cm ): 3454, 3190, 3050, 1613, 1560, 1467, 1416, 1326,
1
185, 950, 750. H NMR (DMSO-d
6
, 400 MHz): δ
H
7.95-6.73 (m, 12H, aromatic), 8.85 (s,
). C NMR (100 MHz, DMSO-d , ppm): δ 175.95,
64.21, 154.38, 132.66, 132.20, 119.47, 116.57, 78.82, 41.56, 40.11, 39.06, 30.72, 23.00.
1
3
H, H-C=N) 2.99-2.34 (m, 6H, CH
2
6
C
Oxidation of cyclohexane
The alkane oxidations were typically carried out in air, in 50 mL round bottom flask,
cyclohexane (0.08 g, 1 mmol), m-chloroperoxybenzoic acid (0.69 g, 4 mmol), VO LG (0.01
2
mmol) were added and stirred vigorously. The reaction mixtures were stirred at ambient
o
temperature for 20 minutes and then were raised to 100 C for 2 h. The oxidation reactions
were monitored by withdrawing small aliquots after different periods of time, which were
then cooled, extract and dried over anhydrous sodium sulfate. The oxidized product was
purified by column chromatography. The product was ascertained by comparison with the
1
authentic sample using H NMR spectroscopy.
Results and discussion
The vanadium(V) complex was obtained by reaction of hydrazone ligand with one equivalent
of vanadium pentoxide and sodium carbonate, in methanol (Scheme 2). VO
in methanol, ethanol, benzene, toluene, acetone, ether, and acetonitrile but soluble in
dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The characterization of VO LG
has been carried out using elemental analysis, IR, NMR spectroscopy, and single crystal X-
ray diffraction. The IR spectrum of VO LG exhibit a strong band in the ranges of 950-960
cm , which are the signature of oxidovanadium(V) compounds and are assigned to
2
LG is insoluble
2
2
-1
-1
-1
ν(O=V=O) [33, 34]. The characteristic bands at 1613 cm and 1560 cm are assigned to
1
ν(C=C) and ν(C=N) of the coordinated hydrazone ligand. The H NMR spectrum of VO
2
LG
exhibits a peaks at δ = 8.85 ppm, which is assigned to methylene proton (H-C=N), the peaks
at δ = 7.95-6.73 ppm appeared as multiplets, which are assigned to aromatic protons.
Similarly, the -CH protons appeared at the expected position and resonates at δ = 2.99-2.34.
2

Scheme 2. Schematic diagram showing the preparation of vanadium(V) complex (VO LG)
2
Crystal structure description
The X-ray quality crystal structure of VO
2
LG was obtained upon slow evaporation of DMF
LG consists of two vanadium ions,
solution of the compound, at room temperature. VO
2
bridging sodium ions, and hydrazone ligand. The crystal structure is shown in Figure 1,
crystallographic data are summarized in Table 1, whereas selected bond lengths and bond
angles are presented in Tables 2 & 3. The compound crystallized in triclinic with P-1 space
group. The hydrazone ligand acts as bis(tridentate) N
2
4
O chelating ligand to two vanadium
ions. The basal positions are occupied by O- naphtholic, O- enolic and the N-imine atoms of
chelating ligand, whereas the terminal positions are occupied by two oxido groups. The metal
ligand bond distances are 1.867(5) Å (V1−O1), 1.959(5) Å (V1−O2), 2.126(7) Å (V1−N1),
1
2
.653(6) Å (V1=O4), 1.999(6) Å (V2−O6), 1.630(6) Å (V2=O7), 1.614(6) Å (V2=O8), and
o
.115(7) (V2−N4). The trans angles in VO
2
LG are O4−V1−N1 (145.7(3) ) and O1−V1−O2
o
(
144.3(3) ) around V1 with geometrical index, τ = 0.02, whereas the trans angles around V1
o
o
are O5−V2−O6 (154.6(3) ) and O7−V2−N4 (128.2(3) ) , with τ = 0.44, respectively. Hence,
vanadium ions adopted a square pyramidal geometry with slight distortion. The geometrical
bond lengths and bond angles of the vanadium(V) complex are compared with the literature
reports containing the similar complexes and found to be similar [33, 34].

Figure 1. Crystal structure of vanadium(V) complex (VO LG)
2
Packing diagram
The crystal packing diagram of VO LG, shows supramolecular interaction as shown in
2
Figure 2, the molecular packing involves a classical hydrogen bonding and pi-pi staging
interactions. The geometrical hydrogen bond lengths and their symmetry codes are
O(9)−H(9A)∙∙∙O(8), (3.028(10) Å [1+x,y,z]; O(9)−H(9B)∙∙∙O(13), 2.845(11) Å [1-x,-y,1-z];
O(11)−H(11A)∙∙∙O(4), 2.971(11) Å [-x,-y,1-z]; O(11)−H(11B)∙∙∙O(16), 2.822(11) Å [x,-
1
+y,z]; O(13)−H(13A)∙∙∙O(9), 2.846(11) Å [1-x,-y,1-z]; O(16)−H(16A)∙∙∙O(12), 2.840(10) Å
[x,1+y,z] and O(16)−H(16B)∙∙∙O(3), 2.836(9) Å [1-x,1-y,1-z] with their corresponding
o
geometrical bond angles ranging from 134-155 . respectively. The crystal structure of
VO LG was found to be stabilized by intermolecular hydrogen bonding (O−H∙∙∙O) and pi-pi
2
stacking interactions. These intermolecular interactions also strengthen and facilitate the
O∙∙∙O interactions in the complex. These packing may be arises as a result of the overall
packing of the molecules in the crystal lattice. The O∙∙∙O intermolecular distance in VO
2
LG is
2
.794 Å, (O ∙∙∙O14). Clearly, the O∙∙∙O intermolecular distance in the O-linked complex is less
4
than the sum of van der Waals atomic radii of oxygen 3.00 Å (rvdW (O) = 1.50 Å). These
interactions are analogous with recently reported in the literature [35, 36].

A
B
Figure 2. (A) Perspective view packing diagram of VO
and (B) Pi-pi staging and O∙∙∙O interactions
Oxidation of cyclohexane
2
LG showing O−H∙∙∙O interactions
The oxidation processed for the catalytic oxidation of cyclohexane to cyclohexanol and
cyclohexanone was carried out under the favourable optimisation reaction conditions. The
reaction conditions for selective oxidation of cyclohexane such as effect of solvents, amounts
of catalyst, cyclohexane, mCPBA molar ratios, and reaction time were optimized. Hence, in
most of the catalytic oxidation of cyclohexane, solvents play a very important role in the
activity of catalyst. The effects of solvents was evaluated on the model reactions and
summarized in Figure 3. It is evident from Figure 3, the reaction proceeded well under

solvents free conditions. It was also noticed that, no cyclohexane oxidation takes place in the
absence of the metal complex or the oxidant. Further, there was an increase in percentage
yield of the product on increasing the amount of catalyst by 1.5- 3 mg. However, varying the
amounts of catalyst from 3-5 mg, there was no such augmentation in the yield.
Figure 3. Effect of solvent and the amount of catalyst on oxidation of cyclohexane
The further probe the potential of VO LG/ mCPBA catalytic system, the effects of different
2
type of oxidant and oxidant/catalyst ratios was also studied. It was observed that increase the
oxidant/catalyst molar ratios increases the rate of oxidation. Other oxidants such as hydrogen
peroxide, benzoyl peroxide and ter-butyl hydroperoxide (TBHP) were also tested, but it was
found that mCPBA gave highest yield. Further, it was also notice that using m-
chloroperoxybenzoic acid as an oxidizing agent, there was an enhancement in product
formation. This behaviour may be due to the strongest oxidizing character of m-
chloroperoxybenzoic acid (mCPBA) [37]. Hence, from the above standardized protocols we
observed that the catalytic systems proceed well using the following reaction condition, using
catalyst (2.5 mg), cyclohexane (5 mL, 5 mmol), cyclohexane: mCPBA mole ratio (1:4) under
o
solvents free condition. Screening of the temperature indicated that, 100 C is the best choice
yielded 37 % of cyclohexone and 41 % cyclohexanol, lowering the reaction temperature to 30
°
C gave rise to a much lower yield (Figure 4). The products yields for catalytic oxidation
of cyclohexane to cyclohexanol and cyclohexone are given in Table 4. Hence, using the
above standardization protocols, we also carried out the catalytic studies for the
oxidation of cyclopentane. Similarly, it was found that the complex also catalyse the

oxidation of cyclopentane to the corresponding cyclopentanone and cyclopentanol, but
their catalytic activity is lower than that for the oxidation of cyclohexane (Table 4).
Figure 4. Effect of temperature for catalytic oxidation of cyclohexane
To account for the transformation, a proposed catalytic cycle for the catalytic oxidation of
cyclohexane is shown in Scheme 3. In the first step, cyclohexane is activated by m-CPBA to
produce cyclohexyl radical. In the second step, the cyclohexyl radical interact with the
peroxo group of the catalyst, which results in proton transfer resulting in the formation of
cyclohexanol and further oxidation which lead to formation cyclohexanone [37].

Scheme 3. The possible reaction mechanism for oxidation of cyclohexane
Conclusion
In summary, we have successfully investigated and compared the catalytic activity of
homobimetallic vanadium(V) complex containing dihydrazone ligand with tridentate -ONO-
donors ligand. The catalytic activity was carried out successfully using m-chloroperbenzoic
acid as an oxidizing agent under solvent free condition. The advantages of these present
protocols are mild and environmentally benign, which are the significant features towards the
development of a sustainable chemical process for oxidations. In view of the whole process
involved and the literatures report available, vanadium(V) complex found to be a promising
candidates for catalytic oxidation of cyclohexane and cyclopentane.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgements
Sunshine D. Kurbah would like to thank Head SAIF, North-Eastern Hill University,
Shillong-793022, India for providing NMR spectra. DST-PURSE SCXRD, NEHU-SAIF,
Shillong, India for providing Single crystal X-ray analysis.
References
[
[
[
1]
2]
3]
C. Jia, T. Kitamura, Y. Fujiwara, Acc. Chem. Res. 34 (2001) 633-639.
E. Shilov, G. B. Shulpin, Chem. Rev. 97 (1997) 2879-2932.
P. M. Reis, J. A. L. Silva, J. J. R. F. da Silva, A. J. L. Pombeiro, Chem. Commun.
(2000) 1845-1846.
[
[
[
[
4]
5]
6]
7]
G. Dyker, Angew. Chem. Int. Ed. 38 (1999) 1698-1712.
R. Raja, G. Shankar, J.M. Thomas, J. Am. Chem. Soc. 121 (1999) 11926.
G. Qian, D. Ji, G. Lu, R. Zhao, Y. Qi, J. Suo, J. Catal. 232 (2005) 378.
T. F. S. Silva, K. V. Luzyanin, M. V. Kirillova, M. F. Guedes da Silva, L. M. D. R. S.
Martins, A. J. L. Pombeiro, Adv. Synth. Catal. 352 (2010) 171.
T. F. S. Silva, E. C. B. A. Alegria, L. M. D. R. S. Martins, A. J. L. Pombeiro, Adv.
Synth. Catal. 350 (2008) 706.
[
8]
9]
[
[
G. S. Mishra, A. J. L. Pombeiro, J. Mol. Catal. A Chem. 239 (2005) 96.
10] D. X. Ren, N. Xing, H. Shan, C. Chen, Y. Z. Cao, Y. H. Xing, Dalton Trans. 42
2013) 5379-5389.
(
[
11] A. E. Shilov, G. B. Shulpin, Activation and Catalytic Reactions of Saturated
Hydrocarbons in the Presence of Metal Complexes; Kluwer Academic Publishers:

New York, USA; Boston, MA, USA; Dordrecht, Holland; London, UK; Moscow,
Russia (2002).
[
[
12] S. A. Chavan, D. Srinivas, P. Ratnasamy, J. Catal. 212 (2002) 39.
13] N. Perkas, Y. Holypin, O. Patalik, A. Gedonken, S. Chandrasekhran, Appl. Catal. A:
Gen. 209 (2001) 125.
[
[
[
[
14] K. Godula, B. Sezen and D. Sames, J. Am. Chem. Soc. 127 (2005) 3648.
15] R. F. Jordan and D. F. Taylor, J. Am. Chem. Soc. 111 (1989) 778.
16] M. Murakami and S. Hori, J. Am. Chem. Soc. 125 (2003) 4720.
17] A. M. Berman, J. C. Lewis, R. G. Bergman and J. A. Ellman, J. Am. Chem. Soc. 130
(2008) 14926.
[
[
[
18] J. Y. Cho, C. N. Iverson, M. R. Smith, J. Am. Chem. Soc. 122 (2000) 12868.
19] J. C. Lewis, R. G. Bergman and J. A. Ellman, J. Am. Chem. Soc. 129 (2007) 5332.
20] (a) D. F. Fischer and R. Sarpong, J. Am. Chem. Soc. 132 (2010) 5926; (b) J. Takagi,
K. Sato, J. F. Hartwig, T. Ishiyama, N. Miyaura, Tetrahedron Lett. 43 (2002) 5649.
21] I. A. I. Mkhalid, D. N. Coventry, D. Albesa-Jove, A. S. Batsanov, J. A. K.Howard, R.
N. Perutz, T. B. Marder, Angew. Chem. Int. Ed. 45 (2006) 489.
[
[
[
22] J. M. Murphy, X. Liao, J. F. Hartwig, J. Am. Chem. Soc. 129 (2007) 15434.
23] T. E. Hurst, T. K. Macklin, M. Becker, E. Hartmann, W. Kügel, J. C. P. L. Salle, A. S.
Batsanov, T. B. Marder, V. Snieckus, Chem. Eur. J. 16 (2010) 8155.
[
[
[
24] T. F. S. Silva, E. C. B. A. Alegria, L. M. D. R. S. Martins, A. J. L. Pombeiro, Adv.
Synth. Catal. 350 (2008) 706.
25] T. F. S. Silva, K. V. Luzyanin, M. V. Kirillova, M. F. Guedes da Silva, L. M. D. R. S.
Martins, A. J. L. Pombeiro, Adv. Synth. Catal. 352 (2010) 171.
26] D. Dragancea, N. Talmaci, S. Shova, G. Novitchi, D. Darvasiova, P. Rapta, M. Breza,
M. Galanski, J. Kozısek, N. M. R. Martins, L. M. D. R. S. Martins, A. J. L. Pombeiro,
V. B. Arion, Inorg. Chem. 55 (2016) 9187-9203.
[
[
27] I. Gryca, K. Czerwinska, B. Machura, A. Chrobok, L. S. Shulpina, M. L. Kuznetsov,
D. S. Nesterov, Y. N. Kozlov, A. J. L. Pombeiro, I. A. Varyan, G. B. Shulpin, Inorg.
Chem. 57 (2018) 1824-1839.
28] M. Sutradhar, L. M. D. R. S. Martins, T. R. Barman, M. L. Kuznetsov, M. F. C.
Guedes da Silva, A. J. L. Pombeiro, New J. Chem. 43 (2019) 17557-17570.
29] S. K. Hanson, R. Wu, L. A. “Pete” Silks, Org. Lett. 13 (2011) 1908-1911.
30] S. Gupta, M. V. Kirillova, M. F. C. Guedes da Silva, A. J. L. Pombeiro, A. M.
Kirillov, Inorg. Chem. 52 (2013) 8601-8611.
[
[

[
[
[
[
31] G. M. Sheldrick, SADABS Program for Empirical Absorption Correction of Area
Detector Data, University of Gottingen Gottingen, Germany (1996).
32] G. M. Sheldrick, SHELXL-14 Program for Crystal Structure Refinements, University
of Gottingen Gottingen, Germany (1996).
33] (a) S. D. Kurbah, Ram A. Lal, New J. Chem. 44 (2020) 5410-5418; (b) S. D. Kurbah,
I. Syiemlieh and R. A. Lal, R. Soc. Open Sci. 5 (2018) 171471.
34] (a) M. R. Maurya, C. Haldar, A. A. Khan, A. Azam, A. Salahuddin, A. Kumar, J. C.
Pessoa, Eur. J. Inorg. Chem. (2012) 2560-2577; (b) S. D. Kurbah, A. Kumar, I.
Syiemlieh, R. A. Lal, Polyhedron. 139 (2018) 80-88.
[
[
35] S. A. Alvarez, cartography of the van der Waals territories, Dalton Trans. 42 (2013)
8
617-8636.
36] G. R. Desiraju, P. S. Ho, L. Kloo, A. C. Legon, R. Marquardt, P. Metrangolo, P.
Politzer, G. Resnati, K. Rissanen, Definition of the halogen bond (IUPAC
Recommendations 2013). Pure Appl. Chem. 85 (2013) 1711-1713.
[
37] T. F. S. Silva, T. C.O. Mac Leoda, L. M. D. R. S. Martinsa, M. F. C. Guedes da Silva,
M. A. Schiavond, A. J. L. Pombeiro, J. Mol. Catal A: Chem, 367 (2013) 52-60.

Table 1. Crystal data and structure refinement for VO LG
2
Empirical formula
C
30
H
37
N
5
Na
2
O
16
V
2
Formula weight
871.50
Temperature/K
Crystal system
296.08(11)
triclinic
Space group
P-1
a/Å
b/Å
c/Å
α/°
β/°
γ/°
Volume/Å3
8.3309(6)
11.9489(19)
19.6741(15)
98.623(9)
91.246(6)
104.582(10)
1870.3(4)
2
Z
Radiation
Data/restraints/parameters
Goodness-of-fit on F
MoKα (λ = 0.71073)
6537/0/505
1.512
2
Final R indexes [I>=2σ (I)]
Final R indexes [all data]
R
R
1
= 0.1357, wR
= 0.1559, wR
2
2
= 0.3849
= 0.4016
1
Table 2. Bond Lengths for VO
Atom Atom Length/Å
2
LG
V1
V1
V1
V1
V1
V2
V2
V2
V2
V2
O1
O3
O2
N1
O4
O7
O8
O6
N4
O5
1.867(5)
1.611(6)
1.959(5)
2.126(7)
1.653(6)
1.630(6)
1.614(6)
1.999(6)
2.115(7)
1.897(6)
Table 3. Bond Angles for VO
2
LG.
Atom Atom Atom Angle/˚
O1
O1
O3
O3
O3
O3
O2
O4
O4
V1
V1
V1
V1
V1
V1
V1
V1
V1
O2
N1
O1
O2
N1
O4
N1
O1
O2
144.3(3)
80.9(2)
105.3(3)
104.3(3)
102.8(3)
110.6(4)
73.3(2)
97.3(3)
90.7(3)

O4
O7
O7
O7
O8
O8
O8
O8
O6
O5
O5
V1
V2
V2
V2
V2
V2
V2
V2
V2
V2
V2
N1
O6
N4
O5
O7
O6
N4
O5
N4
O6
N4
145.7(3)
95.8(3)
128.2(3)
95.9(3)
108.6(3)
94.8(3)
122.6(3)
102.7(3)
73.9(2)
154.6(3)
81.1(3)
Table 4. Oxidation of cyclohexane and cyclopentane catalyzed by bimetallic vanadium(V)
complexa
Yield %
Yield %
Entry Catalyst
Time / h Cyclohexanol Cyclohexanone Cyclopentanol Cyclopentanone
1
2
3
4
5
1.0 mg
1.5 mg
2.0 mg
2.5 mg
3.0 mg
2
2
2
2
2
7
2
7
12
37
18
5
3
5
9
27
17
13
23
41
29
10
19
30
24
a
Reaction conditions (unless stated otherwise): Catalyst (2.5 mg); cyclohexane (5 mL,
o
5
mmol); cyclohexane: mCPBA mole ratio (1:4); Temperature(100 C), under solvents free
b, c
condition. GC yield.

Highlights
Vanadium(V) complex was synthesized in good yield and characterized by FT-IR, UV-
Visible and NMR spectroscopy.
The structure of the complex was confirmed by single X-ray crystallography. The complex
featuring O∙∙∙O chalcogen bonding interaction and other short interaction.
Oxidations of cyclohexane to cyclohexanol were also carried out, using the synthetic
complex as a catalyst.
The catalytic protocols are very simple and the catalyst can be recovered without any lost in
products formation in the next consecutive cycle.

Conflict of interest
The authors declare no conflict of interest.
Author Statement
Dr. Sunshine Dominic Kurbah, designed the study, prepared all the necessary data for
analysis, interpreted the results and wrote the paper.
Ndege Simisi Clovis, prepared the XRD portion and revised the English of the paper.