A new series of moisture resistant metallacyclic titanium(IV) derivatives prepared from 8-hydroxyquinoline of the general formulae [(Q2)Ti{(L1)(L2OR)}] (3a-b, 3d-e), [(Q2)Ti{(L1)(L3)}] (3c and 3f) and [(Q2)Ti(L4)] (3g and 3h) is synthesized by interacting the precursor molecule [(Q2)Ti(OiPr)2] (2) with various 2-heteroaryl methyl ketone oximes and various alkoxyalkanols/2-hydroxypyridine or only with catechol/resorcinol in 1:1:1 or in 1:1 molar ratios in anhydrous boiling toluene (where, HQ = 8-hydroxyquinoline; iPr = isopropyl; L1H = HONC(Me)py-2/HONC(Me)fu-2; L2 = O-CH2-CH2-; R = CH3, C2H5; L3H = 2-hydroxypyridine and L4H = catechol/resorcinol). Stability study revealed that these molecules were stable for a period of 72 h. Mononuclear nature of the complexes was confirmed through mass spectral analysis. Thermogravimetric results explain the multistage fragmentation of the complexes at 900 ºC. NMR, FTIR, and UV-visible spectral data suggested that titanium-ligands attachment is in a hexa-coordinated manner. Additionally, all these molecules were tested for their tumour inhibiting potential against MDA-MB-231 human breast carcinoma cell line. © 2019 Chemical Publishing Co.. All rights reserved.

Madhvesh Pathak

Department of Chemistry

School of Advanced Sciences

Vellore Campus

Samuel B

Fulltext

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Asian Journal of Chemistry

A new class of moisture stable heteroleptic titanium(IV) complexes, synthesized from 8-hydroxyquinoline of the type [(Q)2Ti(2-O-5-X-C6H3CH2NC6H4R] (3a-j), was prepared by reacting the antecedent molecule [(Q2)Ti(OiPr)2] (2) with various 2-hydroxy-N-phenyl-benzylamine analogues in 1:1 molar ratios in dry toluene (where, HQ = 8-hydroxyquinoline; iPr = isopropyl; R = H, 4-CH3, 4-OCH3, 2-Cl, 4-Cl, 2-Br, 4-Br; X= H, Br). Moisture sensitive study disclosed that these new metal complexes were unreacted for 72 h. Mass spectral data were employed for proving the mono-nuclearity of the new derivatives. Thermal decomposition pattern of the new derivatives was explained by thermogravimetric analyses. Elemental analyses data are in concordance with their expected values. The hexa-coordinated way of titanium-ligand linkage is further proved through NMR, FTIR, and UV-visible spectral studies. The cytotoxic efficiency of new complexes was tested against MDA-MB-231 human breast carcinoma cell line. Complex 3a exhibited the highest cytotoxic potential of 0.039 μM in comparison to all its analogues of this series by employing cisplatin as the standard

Synthesis, Characterization, Stability and Cytotoxic Evaluation of Novel Titanium(IV)Complexes of 8-Hydroxyquinoline and 2-Hydroxy-N-phenylbenzylamine Derivatives

Systematic efforts have been made for the synthesis of moisture stable derivatives of titanium (IV) with both nitrogen- and sulfur-based ligands. New heteroleptic titanium (IV) complexes derived from 8-hydroxyquinoline (HQ) of the types [(Q2)Ti{((OiPr)2-n(L1OR1)n-1)(L1OR)}] (3a–3c), [(Q2)Ti(OiPr)2-n(L2)] (3d, 3g), [(Q2)Ti(L1OR)(L2)] (3e, 3f, 3h, 3i) were prepared by treating the precursor [(Q2)Ti(OiPr)2] (2) with different alkoxyalkanols, 2-hydroxypyridine (HPy), and 2-hetroaryl methyl ketone oxime in different mole ratios using anhydrous toluene as solvent (where, n&nbsp;=&nbsp;1–2, HQ&nbsp;=&nbsp;8-HQ, iPr&nbsp;=&nbsp;isopropyl, L1&nbsp;=&nbsp;O–CH2–CH2–, R&nbsp;=&nbsp;CH3, C2H5, R1&nbsp;=&nbsp;C2H5, and L2H&nbsp;=&nbsp;2-HPy, HONC(Me)th-2). Stability study of all these complexes were performed by UV–Visible (UV–Vis) spectroscopy at room temperature and was interpreted on the basis of absorption band arose due to ligand-to-metal charge transfer. All these complexes have good stability against hydrolysis and the shift observed in the absorption band was negligible even after the duration of 72&nbsp;h persistence in 9:1 mixture of dimethyl sulfoxide and water. All the derivatives were characterized by various physicochemical techniques such as NMR (1H, 13C), Elemental Analysis, Mass, Thermogravimetric Analysis (TGA), FT-IR, and UV–Vis spectroscopy. Monomeric nature of all these derivatives was confirmed by mass spectra. TGA describes the multistage decomposition of complexes at 900&nbsp;°C. Elemental analyses results are in agreement with the theoretical values. Other spectral data (NMR, FTIR, and UV–Vis) propose the attachment of titanium and ligands in hexa-coordinated fashion. Further, these were subjected for antibacterial and antifungal evaluation against a panel of microorganisms. Complex 3i has shown better activity compared to all its analogs of this series and it was more potent than the standard drugs gentamicin and fluconazole with minimum inhibitory concentrations of 0.017&nbsp;µM against the Escherichia coli and 0.035&nbsp;µM for Aspergillus niger, respectively.

Medicinal Chemistry Research

Moisture stable heteroleptic titanium (IV) complexes derived from 8-hydroxyquinoline: synthesis, antibacterial, and antifungal studies

Titanium complexes of the type [(OPri)4-nTi(OC2H 4OR)n], [(acac)2Ti(O-G-O] and [(acac) 2Ti(OPri)(OCH2CH2SH)] were synthesized from stoichiometric reactions between titanium tetraisopropoxide [(Ti(OPri)4, TPT] and alkoxyalkanols {HOCH2CH 2OR} in 1:1 to 1:4 molar ratios, where R = Et and n-Bu and by the interaction of the precursor [(acac)2Ti(OR)2] with different diols and thiol in 1:1 molar ratio, where G = (CH2) 2, (CH2)5 and C(CH3) 2CH2CH(CH3), R = isoprop. The reactions have been carried out in refluxing benzene under anhydrous conditions to yield mononuclear derivatives. All these compounds were purified by distillation under reduced pressure. On the basis of elemental analysis, IR and NMR (1H and 13C) spectral studies tetrahedral as well as a cis octahedral geometry around Ti(IV) is proposed.

Alkoxyalkanol and Diol Modified Titanium Tetraisopropoxide: Synthesis and Characterization of Some Novel Precursors for Titania

Novel structural arrangements for alkoxyalkanol modified titanium tetraisopropoxide [(Ti(OPri)4, TPT] were obtained from stoichiometric reactions between TPT and alkoxyalkanols {HOCH2CH2OR,where R= Me, Et}. All the 1:1, 1:2, 1:3 and 1:4 reactions in refluxing benzene form mononuclear species [(OPri)4-nTi(OC2H4OR)n]. All these compounds can be purified by distillation under reduced pressure. On the basis of IR and NMR (1H &amp;13C) spectral studies all the mononuclear derivatives have been obtained in tetrahedral geometry around titanium atom.

Advanced Materials Research

Alkoxyalkanol Modified Ti(OCHMe2)4: Synthesis and Characterization of Novel [(OPri)4-nTi (OC2H4OR)n]

CA: A Cancer Journal for Clinicians

Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries

Inorganics

Acknowledgement to Reviewers of Inorganics in 2017

A New Series of Moisture Stable Metallacyclic Heteroleptic Titanium(IV) Complexes of 8-Hydroxyquinoline: Synthesis, Characterization, Stability Study and Cytotoxicity Evaluation

Journal	Asian Journal of Chemistry
Publisher	Asian Journal of Chemistry
ISSN	0970-7077
Open Access	Yes