Browsing by Author "Rakesh Kumar Gupta"

Now showing 1 - 20 of 37

A dual-responsive "turn-on" bifunctional receptor: A chemosensor for Fe3+ and chemodosimeter for Hg2+
(Royal Society of Chemistry, 2015) Sujay Mukhopadhyay; Rakesh Kumar Gupta; Arnab Biswas; Amit Kumar; Mrigendra Dubey; Maninder Singh Hundal; Daya Shankar Pandey
Synthesis of L1-L3, their thorough characterization by spectral as well as structural studies and use in selective photochemical detection of Fe3+ and Hg2+ at ppb level have been described. Notably, these exhibit bifunctional behaviour toward Fe3+ (CHEF) and Hg2+ (chemodosimetric) which has been unequivocally established by various studies. © The Royal Society of Chemistry 2015.
A highly selective and femto-molar sensitive fluorescence 'turn-on' chemodosimeter for Hg2+
(2014) Sujay Mukhopadhyay; Arnab Biswas; Rampal Pandey; Rakesh Kumar Gupta; Daya Shankar Pandey
A selective fluorescence 'turn-on' chemodosimeter N,N′-bis-(4- cyanobenzylidene)-2,4,6-trimethylbenzene-1,3-diamine (3) based on a Schiff base for femto-molar detection of the Hg2+ has been described. It presents the highest level of detection limit for Hg2+ through Schiff base hydrolysis. © 2014 Elsevier Ltd. All rights reserved.
A schiff base and its copper(II) complex as a highly selective chemodosimeter for mercury(II) involving preferential hydrolysis of aldimine over an ester group
(American Chemical Society, 2014) Ashish Kumar; Mrigendra Dubey; Rampal Pandey; Rakesh Kumar Gupta; Amit Kumar; Alok Ch. Kalita; Daya Shankar Pandey
The syntheses of a new Schiff base, diethyl-5-(2-hydroxybenzylidene) aminoisophthalate (HL), and a copper complex, [Cu(L2)] (1), imparting L-, have been described. Both the ligand HL and complex 1 have been thoroughly characterized by elemental analyses, electrospray ionization mass spectrometry, FT-IR, NMR (1H and 13C), electronic absorption, and emission spectral studies and their structures determined by X-ray single-crystal analyses. Distinctive chemodosimetric behavior of HL and 1 toward Hg2+ has been established by UV/vis, emission, and mass spectral studies. Comparative studies further revealed that the chemodosimetric response solely originates from selective hydrolysis of the aldimine moiety over the ester group and 1 exhibited greater selectivity toward Hg2+ relative to HL while the sensitivity order is reversed. Further, these followed different hydrolytic pathways but ended up with the same product analyzed for diethyl-5-aminoisophthalate (DEA). Hg2+-induced displacement of Cu2+ and subsequent hydrolysis of the -HC=N- moiety in 1 affirmed the identity of the actual species undergoing hydrolysis as HL. The occurrence of Cu2+ displacement and Hg2+ detection via hydrolytic transformation has been supported by various physicochemical studies. © 2014 American Chemical Society.
Association of intronic variants (Apal and Bsml) of vitamin D receptor gene with uterine leiomyoma among North Indian women
(Elsevier B.V., 2025) Sonal Tiwari; Rakesh Kumar Gupta; Sakshi Agarwal; Amita Diwakar; Arun K. Bind; Pawan Kumar Dubey
Background: Understanding the genetic factors involved in the Uterine Leiomyoma (UL) development is crucial for exploring the complexities of UL disorders. This study aimed to examine genetic association between UL incidence and intronic polymorphisms of vitamin D receptor gene in north Indian population. Methodology: Total 200 subjects (100 healthy women and 100 with uterine leiomyomas) of age- and gender-matched control subjects, were genotyped for BsmI (rs1544410) and ApaI (rs7975232) polymorphisms in the VDR gene using TETRA ARMS PCR, followed by Sanger sequencing validation. Levels of VDR mRNA and vitamin D were also assessed through quantitative real-time PCR and ELISA respectively. The association of these variants with leiomyomas was analyzed, along with clinico-pathological (obesity) association. Results: ApaI revealed a significant association with UL, especially for the TG genotype (OR = 2.38; 95 % CI, 1.26–––4.51; p = 0.003). In a similar manner, ApaI is associated with an increased risk for UL with all three genetic models. Comparing VDR ApaI polymorphism between obese and non-obese patients revealed that AC genotype was significantly (OR = 3.71; 95 % CI, 1.53––9.11; p = 0.002) associated with a reduced risk of UL in non-obese patients. The expression of VDR mRNA was two times lower in patients with UL (p < 0.001), along with decreased serum vitamin D levels (p < 0.001). A significant association was also observed between VDR ApaI variant with reduced mRNA expression, vitamin D level and obesity. However, no associations were observed among Bsm1 VDR genotypes and ULs. Conclusion: This study found significant association between the VDR intronic ApaI polymorphism (rs7975232) and the incidence of UL. This VDR variant showed significant association with reduced VDR mRNA expression and serum vitamin D levels in UL patients. However, no significant association was observed between BsmI VDR polymorphism (rs1544410) and UL in North Indian women. © 2025 Elsevier B.V.
Cationic Ru(II), Rh(III) and Ir(III) complexes containing cyclic π-perimeter and 2-aminophenyl benzimidazole ligands: Synthesis, molecular structure, DNA and protein binding, cytotoxicity and anticancer activity
(Elsevier, 2016) Amit Kumar; Ashish Kumar; Rakesh Kumar Gupta; Rajendra Prasad Paitandi; Krishna Beer Singh; Surendra Kumar Trigun; Maninder Singh Hundal; Daya Shankar Pandey
Synthesis, characterization, DNA and protein binding as well as anticancer activity of the organometallic complexes [(η6-C6H6)RuCl(APBI)]Cl (1), [(η6-p-MeC6H4Pri)RuCl(APBI)]Cl (2), [(η6-C6Me6)RuCl(APBI)]Cl (3), [(η5-C5Me5)RhCl(APBI)]Cl·H2O (4) and [(η5-C5Me5)IrCl(APBI)]Cl·H2O (5) containing 2-aminophenyl benzimidazole (APBI) have been described. The complexes 1-5 exhibited strong DNA, protein binding and anticancer activity against cervical cancer (SiHa) cell line. Their binding with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) have been examined by absorption and emission spectral studies. Strong interactions between complexes and CT-DNA have been affirmed by absorption spectral and EthBr displacement studies, while interaction with BSA via static quenching explored by fluorescence titration, synchronous and 3D fluorescence spectroscopy. The interactions between 1-5 and DNA has also been scrutinized by 1H NMR spectral studies using guanosine as a model for DNA. These results have been supported by DFT calculations and molecular docking studies. Cytotoxicity, apoptosis and in vitro anticancer activity of 1-5 toward SiHa cell line have been investigated by MTT assay and acridine (AO)/ethidium bromide (EthBr) fluorescence staining. Overall results revealed that DNA and protein binding, as well as anticancer activity of 1-5 follows the order as 5 > 3 > 2 > 1 > 4. © 2015 Elsevier B.V. All rights reserved.
Corrigendum to ‘Recent developments in metal dipyrrin complexes: Design, synthesis, and applications’ [Coord. Chem. Rev. 414 (2020) 213269] (Coordination Chemistry Reviews (2020) 414, (S0010854519304175), (10.1016/j.ccr.2020.213269))
(Elsevier B.V., 2020) Roop Shikha Singh; Rajendra Prasad Paitandi; Rakesh Kumar Gupta; Daya Shankar Pandey
The authors regret that some of the copyright permissions were omitted from the published version of this review. The corrected figure captions are listed below. The authors apologize for this omission. Fig. 7. Examples of homoleptic complexes based on trivalent metal ions. Reprinted with permission from ref 56. Copyright @ 2006 American Chemical Society. Fig. 9. Structures of Fe(II) complexes of dipyrromethene. Reprinted with permission from ref 12. Copyright @ 2011 American Chemical Society. Fig. 10. Structure of complexes 2 (a), 3 (b) and 4 (c). Reprinted with permission from ref 11. Copyright @ 2009 American Chemical Society. Fig. 12. Chemical structure of dipyrrin 17 and Ga(III) complex 18. Reprinted with permission from ref 76. Copyright @ 2010 American Chemical Society. Fig. 18. Crystal structure of 80 and 81. Reprinted with permission from ref 77. Copyright 2009 The Royal Society of Chemistry. Fig. 22. Structure of metal complex 101. Reprinted with permission from ref 151. Copyright 2016 The Royal Society of Chemistry. Fig. 33. Zn2+ detection by dipyrromethanes 146–148. Reprinted with permission from ref 173. Copyright 2014 The Royal Society of Chemistry. Fig. 38. Complexation of 160 with Cd2+ and Hg2+ ions (a). Crystal structure of 161 (b). Reprinted with permission from ref 181. Copyright 2017 Centre National de la Recherche Scientifique (CNRS) and The Royal Society of Chemistry. Fig. 39. (a) Chemical structures of 162 and 163. Ar = t-Bu; (b) A photograph showing the color changes of 163 (25 mM) in the presence of various anions (40 equiv.) in DMSO; (c) UV–Vis spectral changes of 163 (10 μM) in the presence of F− (0–180 equiv.) in DMSO. Reprinted with permission from ref 186. Copyright 2010 The Royal Society of Chemistry. Fig. 40. (a) Chemical structures of 164–166; (b) and (c) image showing the color changes of probe 166 in the presence of different anions, (b) in CH2Cl2; (c) in DMSO–H2O. Reprinted with permission from ref 187. Copyright 2012 The Royal Society of Chemistry. Fig. 41. (a) Structures of compounds 167–169 bearing α-formyl groups; (b) photograph showing the color changes of solution of 167 in CHCl3 after addition of different anions (1.2 equiv). Reprinted with permission from ref 188. Copyright 2014 The Royal Society of Chemistry. Fig. 44. (a) ORTEP view of the metallotecton Δ-178b. (b) Showing 1-D zig-zag chains of metallotecton Δ-178b linked by hydrogen bonds involving two of the three carboxyl groups of each tecton. Reprinted with permission from ref 194. Copyright 2007 The Royal Society of Chemistry Fig. 45. Crystal structures of 179 and 180. Reprinted with permission from ref 57. Copyright 2009 The Royal Society of Chemistry. Fig. 46. Dimeric structure of dipyrrin 181 (a) and its nickel (II) complex 182 (b) as determined by X-ray crystallography. Representing a portion of the 1-D networks based on the [Formula presented] (12) connectivity pattern of 181 (c) and the distorted square planar/ tetrahedral coordination bonding motif in 182 (d). Reprinted with permission from ref 195. Copyright 2011 The Royal Society of Chemistry. Fig. 48. Showing space-filling representation of coordination polymers formed 199 (top right) and 200 (top left) and stick representation of 200 (bottom) viewed down the crystallographic c-axis, Reprinted with permission from ref 199. Copyright 2004 American Chemical Society. Fig. 49. Chemical structure of 201 (a), Molecular hexagons (b) and helical coordination polymers (c) comprising the supramolecular structure. Reprinted with permission from ref 200. Copyright © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Fig. 50. Chemical structure of 202 (a), ORTEP view of 203 (b) and Ag–π interaction 204. Reprinted with permission from ref 201. Copyright 2007 The Royal Society of Chemistry. Fig. 51. Chemical structures of 205–209 and crystal structure of 210. Reprinted with permission from ref 202. Copyright 2004 American Chemical Society. Fig. 52. (a) Layered structure in a crystal of 209 (b) Ribbon like structure and the packing diagram in a crystal of 210. The hydrogen bonds are denoted by dotted lines. Reprinted with permission from ref 202. Copyright 2004 American Chemical Society. Fig. 54. Chemical structure of 216 (a) and 2-D network (b) formed by its complex with Cu(OAc)2. Reprinted with permission from ref 205. Copyright 2009 The Royal Society of Chemistry. Fig. 56. (a) A portion of the 1-D CP observed in the crystalline phase for 221. (b) A portion of the 1-D hydrogen bonded network in the crystal structure of 222. Reprinted with permission from ref 25. Copyright 2012 The Royal Society of Chemistry. Fig. 59. Portions of the crystal structures of CPs 231–234. Reprinted with permission from ref 207. Copyright 2014 The Royal Society of Chemistry. Fig. 60. Chemical structure of 235, portions of crystal structures of 236 and 237. Reprinted with permission from ref 209. Copyright 2007 The Royal Society of Chemistry. Fig. 69. Chemical structures of 256 and 257. Absorption spectrum of 256 in MeCN. The green area covers excitations of the iridium complex due to LC and MLCT transitions, the red shaded region covers π–π* excitations of the NDI and the blue regions covers excitations of the TAA. The absorption spectrum of 257 (violet solid line) and corresponding phosphorescence spectrum (violet line), excitation spectrum (green solid line). Reprinted with permission from ref 217. Copyright 2013 PCCP Owner Societies. Fig. 72. (a) Image of a free-standing film of 268-SWCNT (thickness of 64 μm). (b) TEM image of 268-SWCNT subjected to electron energy-loss spectroscopy (EELS) mapping. EELS mapping for: (c) carbon K edge intensity and (d) Zn M2 and M3 edge intensities. (e) Overlapped image of (b) and (c). (f) Voltage-difference/temperature difference plots for pristine SWCNTs (black) and 33-SWCNT (orange). (Reprinted with permission from ref 221. Copyright 2015 The Royal Society of Chemistry. Fig. 73. Photoelectric conversion profile using 268 as an active material. (a) Image of a thin film of 268 on a SnO2 electrode. (b) Anodic photocurrent signal after irradiation of a working electrode (SnO2 substrate modified with 268 as shown in (a) with intermittent 500 nm light. (c) Action spectrum for the photocurrent generation (orange dots) and absorption spectrum of 268 on a SnO2 substrate (gray solid line). Reprinted with permission from ref 221. Copyright 2015 The Royal Society of Chemistry. Fig. 74. Structures of dipyrromethene ligand and bis(dipyrrinato)Zn(II) complex; nanosheet 269. Reprinted with permission from ref 222. Copyright © 2015, Springer Nature. Fig. 75. (a) Anodic current response after irradiation of the working electrode (SnO2 substrate modified with 36-layer 269) with intermittent 500 nm light (0.1 M tetrabutylammonium perchlorate with 0.05 M TEOA in acetonitrile) (b) action spectrum for the photocurrent generation (magenta dots) and absorption spectrum of 269 (black solid line). (c) Changes in UV–vis spectra upon stepwise depositions of single-layer 269 on a quartz substrate. (d) Showing linear relationship between the absorbance at 500 nm and number of deposition cycles. Reprinted with permission from ref 222. Copyright © 2015, Springer Nature. Fig. 76. Left: chemical structure of porphyrin–dipyrrin hybrid ligand 271. Right: a) Typical photoelectric conversion response upon irradiation of the 270-physisorbed photoanode with intermittent 440 nm monochromatic light. b) Action spectrum for the photocurrent generation (orange dots) and absorption spectrum of 270 (green solid line). Reprinted with permission from ref 223. 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Fig. 82. (a) Chemical structure of 286 (b) UV–vis spectra showing reductive conversion of Cr(VI) to Cr(III) AuNPs (c) AuNPs@prGO500 (d) The plot of conversion vs. time as monitored by UV–vis spectroscopy (e) Schematic presentation for Cr(VI) reduction on AuNPs@prGO500. Reaction conditions: HCOOH = 0.2 mL, [Cr2O72-] = 0.2 mM and catalytic amount = 1 mg/mL (25 µL) levels (0.1 μM to 0.1 M) in 50 mM phosphate buffer solutions at pH = 4.5. Reprinted with permission from ref 233. Copyright 2016 The Royal Society of Chemistry. Fig. 84. Crystal structure of Pd(II)bis-dipyrrinato complex 293 (Reprinted with permission from ref 237. 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) and Mn(III)-bis(phenolate)dipyrrin complex 294. Fig. 85. Crystal structures of U(VI) complex 295 (a) U(IV) complex 296 (b) and Fe(III) complexes 297 (c), 298 (d) and 299 (e), Reprinted with permission from ref 239 (Copyright 2017 American Chemical Society). Scheme 14. Synthesis and crystal structure of compound 100. Reprinted with permission from ref 150. Copyright 2011 The Royal Society of Chemistry. © 2020
Dipyrrin complex assisted: In situ synthesis of ultra-small gold nanoparticles decorated on a partially reduced graphene oxide nanocomposite for efficient catalytic reduction of Cr(VI) to Cr(III)
(Royal Society of Chemistry, 2016) Rakesh Kumar Gupta; Vinod Kumar; Anchal Srivastava; Daya Shankar Pandey
Rapid and convenient syntheses of ultra-small gold nanoparticles (AuNPs) utilizing a novel heteroleptic dipyrrin complex with dual functionality have been described. The AuNPs immobilized on GO led to partial reduction of GO to form AuNPs/prGO and reduce Cr(vi) to Cr(iii) in the presence of HCOOH with the best performance achieved from AuNPs@prGO500. © 2016 The Royal Society of Chemistry.
DNA binding and anti-cancer activity of redox-active heteroleptic piano-stool Ru(II), Rh(III), and Ir(III) complexes containing 4-(2-methoxypyridyl)phenyldipyrromethene
(2013) Rakesh Kumar Gupta; Rampal Pandey; Gunjan Sharma; Ritika Prasad; Biplob Koch; Saripella Srikrishna; Pei-Zhou Li; Qiang Xu; Daya Shankar Pandey
The synthesis of four novel heteroleptic dipyrrinato complexes [(η6-arene)RuCl(2-pcdpm)] (η6-arene = C 6H6, 1; C10H14, 2) and [(η5-C5Me5)MCl(2-pcdpm)] (M = Rh, 3; Ir, 4) containing a new chelating ligand 4-(2-methoxypyridyl)-phenyldipyrromethene (2-pcdpm) have been described. The complexes 1-4 have been fully characterized by various physicochemical techniques, namely, elemental analyses, spectral (ESI-MS, IR, 1H, 13C NMR, UV/vis) and electrochemical studies (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). Structures of 3 and 4 have been determined crystallographically. In vitro antiproliferative and cytotoxic activity of these complexes has been evaluated by trypan blue exclusion assay, cell morphology, apoptosis, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA fragmentation assay in Dalton lymphoma (DL) cell lines. Interaction of 1-4 with calf thymus DNA (CT DNA) has also been supported by absorption titration and electrochemical studies. Our results suggest that in vitro antitumor activity of 1-4 lies in the order 2 > 1 > 4 > 3. © 2013 American Chemical Society.
DNA/protein binding, molecular docking, and in vitro anticancer activity of some thioether-dipyrrinato complexes
(2013) Rakesh Kumar Gupta; Gunjan Sharma; Rampal Pandey; Amit Kumar; Biplob Koch; Pei-Zhou Li; Qiang Xu; Daya Shankar Pandey
Syntheses and characterizations of the arene ruthenium [(η6- C6H6)RuCl(4-mtdpm)] (1), [(η6-p-MeC 6H4Pri)RuCl(4-mtdpm)] (2), and structurally analogous rhodium/iridium complexes [(η5-C5Me 5)RhCl(4-mtdpm)] (3) and [(η5-C5Me 5)IrCl(4-mtdpm)] (4) [4-mtdpm = 5-(4-methylthiophenyl)dipyrromethene] have been reported. Their identities have been established by satisfactory elemental analyses, electrospray ionization-mass spectrometry (ESI-MS), FT-IR, NMR (1H, 13C), UV/vis, emission spectral, and electrochemical studies. Structure of the representative complex 3 has been authenticated by X-ray single crystal analyses. The complexes 1-4 effectively bind with calf thymus DNA (CT DNA) through intercalative/electrostatic interactions. In addition, these exhibit significant cytotoxicity toward Dalton lymphoma (DL) cell line and cause static quenching of the bovine serum albumin (BSA) fluorophore. The antiproliferative activity, morphological changes, and apoptosis have been evaluated by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder assay. Mode of interaction of the complexes with DNA/protein has also been supported by molecular docking. Various studies revealed remarkable decrease in the in vitro DL cell proliferation and induction of the apoptosis by 1-4, which lies in the order 2 > 1 > 4 > 3. © 2013 American Chemical Society.
Fluorescent azophenol-quinazoline dyad as multichannel reversible pH indicator in aqueous media: An innovative concept on diazo based dyads
(2013) Amit Kumar; Rampal Pandey; Rakesh Kumar Gupta; Daya Shankar Pandey
A novel azophenol-quinazoline dyad 1 has been designed, synthesized and demonstrated as an efficient reversible multichannel pH indicator through distinct signalling in aqueous media. Owing to the competence between highly fluorescent quinazoline moiety and a well known fluorescence quencher diazo group, dyad 1 is moderately fluorescent in nature. Under acidic conditions 1 displays diverse fluorogenic changes (blue emission at pH 4.25; green at pH 1.80) while under basic condition (pH 11.80) chromogenic changes were observed. © 2013 Elsevier Ltd. All rights reserved.
Genetic association of vitamin D receptor polymorphisms (ApaI, BsmI, and FokI) with gestational diabetes mellitus in North Indian women: a case–control study
(BioMed Central Ltd, 2025) Rakesh Kumar Gupta; Sonal Tiwari; Sakshi Agarwal; Amita Diwakar; Pawan Kumar Dubey
Background: Gestational diabetes mellitus (GDM) affects nearly 14% of pregnancies and imposes an increased risk of adverse outcomes for both pregnant women and their developing babies. This study examined the genetic association of vitamin D receptor (VDR) variants (ApaI, BsmI, and FokI) with GDM in the North Indian population. Methods: Tetra-ARMS PCR was used for genotyping of VDR variants followed by Sanger sequencing validation. The genotypes of VDR variants, Odds ratio (OR) and confidence interval (CI) were further analyzed in GDM and determined by different genetic models. Results: The C allele of ApaI (rs7975232) genotype significantly associated with increased risk of GDM compared to the TT genotype carrying pregnant women. The A allele of BsmI, and A allele of FokI genotypes was found as a risk factor for GDM. Sanger sequencing confirmed the changes in ApaI (T/C), BsmI (A/G), and FokI (A/G) gene sequence which linked to GDM. The circulatory vitamin D3 levels were significantly lower in GDM patients whereas, homozygous genotypes of ApaΙ (CC, P < 0.0884), BsmI (GG, P < 0.8192) and FokI (GG, P < 0.0303) was associated with vitamin D deficiency. On other hand, mother age, blood glucose and glycated haemoglobin (HbA1c) were significantly higher in the GDM group vs. the control group. Conclusion: VDR ApaI (rs7975232) and FokI (rs2228570) polymorphisms, HbA1c level, and vitamin D are associated with the risk of GDM in the north Indian population. Considering the impact of vitamin D3 level, it is suggested that pregnant Indian women must consider vitamin D supplementation during pregnancy. © The Author(s) 2025.
Genetic variants related to insulin metabolism are associated with gestational diabetes mellitus
(Elsevier B.V., 2024) Ravi Bhushan; Shafiul Haque; Rakesh Kumar Gupta; Anjali Rani; Amita Diwakar; Sakshi Agarwal; Anima Tripathi; Pawan K. Dubey
The current study sought to investigate the associations of common genetic risk variants with gestational diabetes mellitus (GDM) risk in the north Indian population and to evaluate their utility in identifying GDM cases. A case-control study, including 300 pregnant women, was included, and clinical and pathological information was collected. The amplification-refractory mutation system (ARMS) was used for genotyping four single nucleotide polymorphisms (SNPs), namely FTO (rs9939609), PPARG2 (rs1801282), SLC30A8 (rs13266634), and TCF7L2 (rs12255372). The odds ratio and confidence interval were determined for each SNP in different genetic models. Further, attributable risk, population penetrance, and relative risk were also calculated. The risk allele A of FTO (rs9939609) poses a two times higher risk of GDM (p = 0.02, OR = 2.5). The CG and GG genotypes of PPARG2 (rs1801282) have half a lower risk of GDM. In SLC30A8 (rs13266634), the recessive model analysis showed a two times higher risk of having GDM, while the recessive model (TT vs. GG + GT) analysis in TCF7L2 (rs12255372) indicates a lower risk of GDM. Finally, the relative risk, population penetrance, and attributable risk for risk allele in all four variants was higher in GDM mothers. All four polymorphisms were found to be significantly associated with BMI, HbA1c, and insulin. Our study first time confirmed a significant association with GDM for four variants, FTO, PPARG2, SLC30A8, and TCF7L2, in the North Indian population. © 2024 Elsevier B.V.
Half-sandwich arene ruthenium complexes: Synthetic strategies and relevance in catalysis
(Royal Society of Chemistry, 2014) Prashant Kumar; Rakesh Kumar Gupta; Daya Shankar Pandey
Half-sandwich arene ruthenium complexes exhibit versatile chemistry, serve as excellent precursors and find potential applications in many organic transformations. This review mainly focuses on the chemistry of piano-stool ruthenium complexes with special emphasis on the achiral or chiral-at-ruthenium center. Also, it deals with the synthesis, nomenclature and stereochemistry of arene ruthenium complexes along with mechanistic insights into the epimerization reactions and their applications in catalytic organic transformations with some selected examples. © The Royal Society of Chemistry.
Heteroleptic arene Ru(ii) dipyrrinato complexes: DNA, protein binding and anti-cancer activity against the ACHN cancer cell line
(Royal Society of Chemistry, 2016) Rakesh Kumar Gupta; Amit Kumar; Rajendra Prasad Paitandi; Roop Shikha Singh; Sujay Mukhopadhyay; Shiv Prakash Verma; Parimal Das; Daya Shankar Pandey
Four organometallic complexes [(η6-C6H6)RuCl(pmpzdpm)], 1; [(η6-C6H6)RuCl(pypzdpm)], 2; [(η6-C10H14)RuCl(pmpzdpm)], 3 and [(η6-C10H14)RuCl(pypzdpm)], 4 containing 5-(2-pyrimidyl-piperazine)phenyldipyrromethene (pmpzdpm) and 5-(2-pyridylpiperazine)phenyldipyrromethene (pypzdpm) have been designed and synthesized. The complexes 1-4 have been fully characterized by elemental analyses and spectroscopic studies (ESI-MS, IR, 1H, 13C NMR, UV-vis). Their electrostatic/intercalative interaction with CT DNA has been investigated by UV-vis and competitive ethidium bromide displacement studies while their protein binding affinity toward bovine serum albumin (BSA) was realized by UV-vis, fluorescence, synchronous and three dimensional (3D) fluorescence studies. The interaction with DNA and protein has further been validated by in silico studies. Cellular uptake, in vitro cytotoxicity and flow cytometric analyses have been performed to determine the mode of cell death against the kidney cancer cell line ACHN. Cell cycle analysis suggested that the complexes cause cell cycle arrest in the subG1 phase and overall results indicated that the in vitro antitumor activity of 1-4 lies in the order of 3 > 4 > 1 > 2 (IC50, 7.0 1; 8.0 2; 2.0 3; 4.0 μM, 4). © The Royal Society of Chemistry 2016.
Heteroleptic dipyrrinato complexes containing 5-ferrocenyldipyrromethene and dithiocarbamates as coligands: Selective chromogenic and redox probes
(2012) Rakesh Kumar Gupta; Rampal Pandey; Roopshikha Singh; Nitin Srivastava; Biswajit Maiti; Satyen Saha; Peizhou Li; Qiang Xu; Daya Shankar Pandey
Six heteroleptic dipyrrinato complexes [Ni(fcdpm)(dedtc)] (1), [Ni(fcdpm)(dipdtc)] (2), [Ni(fcdpm)(dbdtc)] (3), [Pd(fcdpm)(dedtc)] (4), [Pd(fcdpm)(dipdtc)] (5), and [Pd(fcdpm)(dbdtc)] (6) (fcdpm = 5-ferrocenyldipyrromethene; dedtc = diethyldithiocarbamate; dipdtc = diisopropyldithiocarbamate; dbdtc = dibutyldithiocarbamate) have been synthesized and characterized by elemental analyses and spectral (ESI-MS, IR, 1H, 13C NMR, UV-vis) and electrochemical studies. Crystal structures of 1, 2, 4, and 5 have been authenticated by X-ray single-crystal analyses. Nickel-based complexes 1-3 display selective chromogenic and redox sensing for Hg2+ and Pb2+ ions, while palladium complexes 4-6 display selective chromogenic and redox sensing only for Hg2+. Electronic absorption, ESI-MS, and electrochemical studies indicated that sensing arises from interaction between 1-3 and Hg2+/Pb2+ through sulfur of the coordinated dithiocarbamates, while it arises from the pyrrolic nitrogen of fcdpm and dithiocarbamate sulfur from 4-6 and Hg 2+. Different modes of binding between Ni and Pd complexes have further been supported by theoretical studies. The receptor-cation binding constants (Ka) and stoichiometry between probes and Hg 2+/Pb2+ have been estimated by the Benesi-Hildebrand method and Job's plot analysis. Detection limits for 1-3 toward Hg 2+/Pb2+ and 4-6 for Hg2+ have been found to be reasonably high. © 2012 American Chemical Society.
Interaction of ferrocene appended Ru(II), Rh(III) and Ir(III) dipyrrinato complexes with DNA/protein, molecular docking and antitumor activity
(Elsevier Masson SAS, 2014) Rajendra Prasad Paitandi; Rakesh Kumar Gupta; Roop Shikha Singh; Gunjan Sharma; Biplob Koch; Daya Shankar Pandey
Efficacy of the ferrocene appended piano-stool dipyrrinato complexes [(η6-C6H6)RuCl(fcdpm)] (1), [(η6-C10H14)RuCl(fcdpm)] (2), [(η6-C12H18)RuCl(fcdpm)] (3) [(η5-C5Me5)RhCl(fcdpm)] (4) and [(η5-C5Me5)IrCl(fcdpm)] (5) [fcdpm = 5-ferrocenyldipyrromethene] toward anticancer activity have been described. Binding of the complexes with calf thymus DNA (CT-DNA) and BSA (bovine serum albumin) have been thoroughly investigated by UV-Vis and fluorescence spectroscopy. Binding constants for 1-5 (range, 104-105 M-1) validated their efficient binding with CT-DNA. Molecular docking studies revealed interaction through minor groove of the DNA, on the other hand these also interact through hydrophobic residues of the protein, particularly cavity in the subdomain IIA. In vitro anticancer activity have been scrutinized by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder (fragmentation) assay against Dalton's Lymphoma (DL) cells. Present study revealed that rhodium complex (4) is more effective relative to ruthenium (1-3) and iridium (5) complexes. © 2014 Elsevier Masson SAS. All rights reserved.
Li+-induced selective gelation of discrete homochiral structural isomers derived from l-tartaric acid
(Royal Society of Chemistry, 2014) Mrigendra Dubey; Ashish Kumar; Rakesh Kumar Gupta; Daya Shankar Pandey
Two chiral structural isomers have been synthesized by molecular engineering of l-tartaric acid. In the presence of LiOH isomer 1 forms a thermally stable, fluorescent gel which exhibits interesting nano-cluster morphology, anomalous optical and rheological properties whilst 2 forms a non-fluorescent solution under similar conditions. The current-voltage (I-V) curve followed a non-linear trend, rationally in close proximity to the diode characteristic curve. This journal is © the Partner Organisations 2014.
Li+-induced selective gelation of discrete homochiral structural isomers derived from l-tartaric acid
(2014) Mrigendra Dubey; Ashish Kumar; Rakesh Kumar Gupta; Daya Shankar Pandey
Two chiral structural isomers have been synthesized by molecular engineering of l-tartaric acid. In the presence of LiOH isomer 1 forms a thermally stable, fluorescent gel which exhibits interesting nano-cluster morphology, anomalous optical and rheological properties whilst 2 forms a non-fluorescent solution under similar conditions. The current–voltage (I–V) curve followed a non-linear trend, rationally in close proximity to the diode characteristic curve. © The Partner Organisations 2014.
Luminescent N,O-chelated chroman-BF2 complexes: Structural variants of BODIPY
(2013) Roop Shikha Singh; Mahendra Yadav; Rakesh Kumar Gupta; Rampal Pandey; Daya Shankar Pandey
The synthesis and characterization of 5-(chromen-4-one)-dipyrromethane (1), 5-(6-methyl-chromen-4-one)-dipyrromethane (2), 5-(6-isopropyl-chromen-4-one)- dipyrromethane (3) and the respective chromans, 7-[2-pyrrolo]-pyrrole[1,2-a]12H pyrrolino[2,3-b]chroman-4-one (4), 4-methyl-7-[2-pyrrolo]-pyrrole[1,2-a]12H pyrrolino[2,3-b]-chroman-4-one (5) and 4-isopropyl-7-[2-pyrrolo]-pyrrole[1,2-a] 12H pyrrolino[2,3-b]-chroman-4-one (6) have been described. Chroman derivatives 4-6 have been used in the synthesis of highly stable, fluorescent, borondifluoride complexes (7-9). All the compounds have been fully characterised by various physicochemical techniques viz., elemental analyses, IR, HRMS, NMR (1H, 13C), electronic absorption, emission (solution and solid state), electrochemical and thermal studies. Crystal structures of dipyrromethanes 1 and 2, chroman derivative 6 and boron complexes 7-9 have been determined by X-ray single crystal analyses. Structural studies revealed that the formation of 4-6 takes place by DDQ mediated C-N coupling. The higher stability of 4-6 relative to their respective dipyrrins has been supported by theoretical studies. © The Royal Society of Chemistry 2013.
Morphological tuning via structural modulations in AIE luminogens with the minimum number of possible variables and their use in live cell imaging
(Royal Society of Chemistry, 2015) Roop Shikha Singh; Rakesh Kumar Gupta; Rajendra Prasad Paitandi; Mrigendra Dubey; Gunjan Sharma; Biplob Koch; Daya Shankar Pandey
With intent to fine tune the morphological and photophysical properties, three novel AIE luminogens (BQ1-BQ3) based on quinoline-BODIPY have been synthesized. A judicious choice of substituents (-H, -CH3, -OCH3) in these systems led to nanoballs in BQ1 and BQ2, while in BQ3 it led to reticulated nanofibers with diverse photophysical behaviours. This journal is © The Royal Society of Chemistry 2015.