<str<strong>on</strong>g>Studies</str<strong>on</strong>g>...Purav Talaviya et al.Table-1: Analysis <strong>of</strong> PBDQ lig<strong>and</strong> <strong>and</strong> its metal chelatesEmpirical Formula Mol. Cal Yield Elemental Analysis (%) Found(Calcd)g/mol % C H N MC 27 H 19 N 7 O 3 489 68 66.25 (66.21) 3.91(3.87) 20.03(19.99) ---C 27 H 17 N 7 O 3 Cu .2H 2 O 586 70 55.24(55.19) 3.61(3.56) 16.70(16.65) 10.82(10.78)C 27 H 17 N 7 O 3 Ni .2H 2 O 582 67 55.6 8(55.64) 3.63(3.58) 16.83(16.79) 10.12(10.07)C 27 H 17 N 7 O 3 Co .2H 2 O 581 67 55.70(55.65) 3.64(3.59) 16.84(15.80) 10.08(10.04)C 27 H 17 N 7 O 3 Mn .2H 2 O 578 66 56.06(56.12) 3.66(3.62) 16.95(16.91) 09.50(09.45)C 27 H 17 N 7 O 3 Zn .2H 2 O 587 68 55.07(55.02) 3.59(3.55) 16.65(16.61) 11.11(11.06Table-2: Spectral features <strong>and</strong> magnetic moment <strong>of</strong> metal chelatesMetalChelatesµ effBMElectr<strong>on</strong>ic Transiti<strong>on</strong>s IR spectral feacturesData cm -1SpectralComm<strong>on</strong> for all cm -1PBDQ -Cu +2PBDQ -Ni +2 1.933.84226901586522988146958100C.TEg → 2 T 2 gA 2 g→ 3 T 1 g(P)A 2 g→ 3 T 1 g(F)A 2 g→ 3 T 2 g3300 Quinoline Moiety2200160015001090 C-O-M &PBDQ -Co +2 4.53 2072019880119904 T 1 g(F)→ 4 A 2 gT 1 g(F)→ 4 T 1 g(P)T 1 g(F)→ 4 T 2 g1420 O-M750 N-M660PBDQ -Mn +2 5.11 2296517655153796 A 1 g→ 6 A 1 g ( 4 Eg)A 1 g→ 4 T 2 g( 4 G)A 1 g→ 4 T 1 g( 4 G)PBDQ -Zn +2 Diamagnetic -----IR Analysis: The important infrared spectral b<strong>and</strong>s <strong>and</strong> their tentative assignments for the synthesizedlig<strong>and</strong> H 2 L <strong>and</strong> its coordinati<strong>on</strong> polymers were recorded as KBr disks <strong>and</strong> are shown in Table-2.IR spectrum <strong>of</strong> lig<strong>and</strong> <strong>of</strong> PBDQ show a broad b<strong>and</strong> extended from 3300 to 2200 cm -1 that might beresp<strong>on</strong>sible to phenolic -OH group b<strong>on</strong>ded to N atom <strong>of</strong> 8-hydroxyquinoline moieties 20 .Several b<strong>and</strong>s appeared between 1500 <strong>and</strong> 1600 cm -1 regi<strong>on</strong> may arised from aromatic breathing <strong>and</strong> 3400cm -1 for –NH group. The IR b<strong>and</strong> at 1580 cm -1 (C=N <strong>of</strong> 8-quinolinol system) <strong>of</strong> PBDQ lig<strong>and</strong> shifted tohigher frequency side 1600 cm -1 in the spectra <strong>of</strong> the metal complexes indicating involvement <strong>of</strong> nitrogen in112 J. Chem. Bio. Phy. Sci. Sec. A, 2012-2013, Vol.3, No.1, 109-116.
<str<strong>on</strong>g>Studies</str<strong>on</strong>g>...Purav Talaviya et al.the complexes formati<strong>on</strong> 21 , whereas the b<strong>and</strong> at 1420 cm -1 in the IR spectrum <strong>of</strong> PBDQ assigned to in-plane–OH deformati<strong>on</strong> was shifted towards higher frequency in the spectra <strong>of</strong> the coordinati<strong>on</strong> polymer due to theformati<strong>on</strong> <strong>of</strong> the M–O b<strong>on</strong>d 22 . This was further c<strong>on</strong>firmed by a weak b<strong>and</strong> at 1090 cm -1 corresp<strong>on</strong>ding to C–O–M stretching, while b<strong>and</strong>s around 750 <strong>and</strong> 660 cm -1 corresp<strong>on</strong>d to the N →M vibrati<strong>on</strong> 2 3.1 H NMR Analysis: The structural analysis <strong>of</strong> the lig<strong>and</strong> (PBDQ) was determined by 1 H NMR spectrum.NMR(DMSO) 6.9 – 8.2 ppm (15H) Multiplet Aromatic5.3 ppm (1H) Singlet (OH)4.0 ppm (1H) Singlet (NH)Magnetic Measurements: Magnetic moments <strong>of</strong> coordinati<strong>on</strong> polymers are given in Table-2. The diffuseelectr<strong>on</strong>ic spectrum <strong>of</strong> Cu +2 complex shows two broad b<strong>and</strong>s, 15865 <strong>and</strong> 22690 cm -1 . The first b<strong>and</strong> may bedue to a 2 Eg → 2 T 2 g transiti<strong>on</strong>, while the sec<strong>on</strong>d b<strong>and</strong> may be due to charge transfer. The first b<strong>and</strong> showsstructures suggesting a distorted octahedral structure for the Cu +2 metal complex 24,25 . The Co +2 metalcomplex gives rise to two absorpti<strong>on</strong> b<strong>and</strong>s at 20720 cm -1 , 19880 cm -1 <strong>and</strong> 11990 cm -1 which can beassigned 4 T 1 g(F)→ 4 A 2 g, 4 T 1 g(F)→ 4 T 1 g(P) <strong>and</strong> 4 T 1 g(F)→ 4 T 2 g transiti<strong>on</strong>s, respectively. These absorpti<strong>on</strong>b<strong>and</strong>s <strong>and</strong> the µ eff value indicate octahedral c<strong>on</strong>figurati<strong>on</strong> <strong>of</strong> the Co +2 metal complex 26,27 . The spectrum <strong>of</strong>Mn +2 polymeric complex comprised three b<strong>and</strong>s at 22965 cm -1 ,17655 cm -1 <strong>and</strong> 15379 cm -1 . These b<strong>and</strong>smay be assigned to 6 A 1 g→ 6 A 1 g( 4 Eg), 6 A 1 g→ 4 T 2 g( 4 G) <strong>and</strong> 6 A 1 g→ 4 T 1 g( 4 G) transiti<strong>on</strong>s, respectively. The highintensity <strong>of</strong> the b<strong>and</strong>s also suggests that they may have some charge transfer character. The magneticmoment is found to be lower than normal range. In the absence <strong>of</strong> low temperature measurement <strong>of</strong>magnetic moment, it is difficult to attach any significance to this. As the spectrum <strong>of</strong> the metal complex <strong>of</strong>Ni +2 show three distinct b<strong>and</strong>s at 22988 cm -1 ,14695 cm -1 <strong>and</strong> 8100 cm -1 are assigned as 3 A 2 g→ 3 T 1 g(P),3 A 2 g→ 3 T 1 g(F) <strong>and</strong> 3 A 2 g→ 3 T 2 g transiti<strong>on</strong>, respectively, suggesting the octahedral envir<strong>on</strong>ment for Ni +2 i<strong>on</strong>.The observed µ eff values in the range 1.93–5.11 B.M are c<strong>on</strong>sistent with the above moiety 28,29 .Thermal <str<strong>on</strong>g>Studies</str<strong>on</strong>g>: The TGA data for the Co-ordinati<strong>on</strong> polymers samples at different temperatures indicatethat the degradati<strong>on</strong> <strong>of</strong> the co-ordinati<strong>on</strong> polymers is noticeable bey<strong>on</strong>d 300 0 C. The rate <strong>of</strong> degradati<strong>on</strong>becomes a maximum at a temperature between 400 <strong>and</strong> 500 0 C. This may be due to accelerati<strong>on</strong> by metaloxides, which form in situ. Each polymer lost about 60% <strong>of</strong> its weight when heated up to 690 0 C. Inspecti<strong>on</strong><strong>of</strong> the thermograms <strong>of</strong> all coordinated polymer samples revealed that all samples suffered appreciableweight loss in the range <strong>of</strong> 150 to 280 0 C. This may be due to the presence <strong>of</strong> a coordinated water molecule.Antimicrobial Activities: The antibacterial <strong>and</strong> antifungal data obtained from analysis are shown inTable-3 <strong>and</strong> Table-4, respectively. The increase in antimicrobial activity may be c<strong>on</strong>sidered in light <strong>of</strong>Overt<strong>on</strong>e’s c<strong>on</strong>cept 30 <strong>and</strong> Tweedy’s chelati<strong>on</strong> theory 31 . According to Overt<strong>on</strong>e’s c<strong>on</strong>cept <strong>of</strong> cellpermeability, the lipid membrane that surrounds the cell favors the passage <strong>on</strong>ly <strong>of</strong> lipid-soluble materialsdue to which liposolubility is an important factor c<strong>on</strong>trolling the antimicrobial activity. On complexati<strong>on</strong>,the polarity <strong>of</strong> the metal i<strong>on</strong> will be reduced largely due to the overlap <strong>of</strong> the lig<strong>and</strong> orbital <strong>and</strong> partialsharing <strong>of</strong> the positive charge <strong>of</strong> the metal i<strong>on</strong> with d<strong>on</strong>or groups. Further, it increases the delocalizati<strong>on</strong> <strong>of</strong> -electr<strong>on</strong>s over the whole chelate ring <strong>and</strong> enhances the lipophilicity <strong>of</strong> the coordinati<strong>on</strong> polymers. Thisincreased lipophilicity enhances the penetrati<strong>on</strong> <strong>of</strong> the coordinati<strong>on</strong> polymer into lipid membranes <strong>and</strong>blocks the metal binding sites in the enzymes <strong>of</strong> microorganisms. These coordinati<strong>on</strong> polymers also disturbthe respirati<strong>on</strong> process <strong>of</strong> the cell <strong>and</strong> thus block the synthesis <strong>of</strong> proteins, which restricts further growth <strong>of</strong>the organisms.113 J. Chem. Bio. Phy. Sci. Sec. A, 2012-2013, Vol.3, No.1, 109-116.
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