Synthesis and Spectroscopic Studies of New Palladium(II) Complexes of N-hydroxymethyl Saccharin (Sac-CH2OH) and Amines or Diaminas Ligands

Al-Samrai

Yousef

2020

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This paper reports the syntheses and spectral investigations of the new complexes [Pd(k1‐S‐ptt)2(k2‐dppmS2)] (1), [Pd(k1‐S‐ptt)2(k2‐dppp)] (2a), [Pd(k1‐N‐ptt)2(k2‐dppp)] (2b), [Pd(k1‐S‐ptt)2(k2‐dpppS2)] (3), [Pd(k1‐S‐ptt)2(k2‐dppb)] (4), [Pd(k1‐S‐ptt)2(k2‐dppf)] (5a) and [Pd(k1‐N‐ptt)2(k2‐dppf)] (5b), derived from 1‐phenyl‐5‐thiol‐1H‐tetrazole (Hptt) and diphosphine (dppmS2, dppp, dpppS2, dppb and dppf) as co‐ligand. The Hptt ligand acts as monodentate through the thiolato sulfur atom in complexes 1, 3 and 4. While in complexes 2 and 5, the Hptt ligand also acts as monodentate through the nitrogen of heterocyclic ring, or sulfur of thiol group after deprotonation, as two linkage isomers. Theoretical calculations on the all complexes were performed, isomers based on 2a, 2b and 5a, 5b reveal that each pair of isomers is isoenergetic. For the 2a and 2b complexes the energy difference was 19.92 kcal mol−1, while for the 5a and 5b complexes the difference was 11.78 kcal mol−1. These differences are relatively small and suggest that the linkage isomers may be in equilibrium in solution. The reasons for the adoption of these different coordination modes are not clear but steric factors are likely to be a major contributory factor. Further, in vitro anti‐bacterial activity and molecular docking analysis has been carried out to study the activity of the compound.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

New palladium (II) complexes with 1‐phenyl‐1H‐tetrazole‐5‐thiol and diphosphine Synthesis, characterization, biological, theoretical calculations and molecular docking studies

Al-Samrai

Yousef

2020

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“…The IR spectra of the trans ‐[Pd( k 1 ‐ S ‐ptt) 2 (Phos) 2 ] ( 2–4 ) showed the ν(C=N) was shifted towards higher frequency compared with Hptt, whereas the ν(C–S) was shifted to a lower frequency. [ 6,7,9,29–31 ] This suggests that ptt − acts as a monodentate ligand bonded to the metal through either the thiol sulfur atom. Also, the spectra showed a new single band within (432–457) cm −1 tentatively assigned to ν(M‐S) in a trans configuration.…”

Section: Resultsmentioning

confidence: 99%

“…Also, the spectra showed a new single band within (432–457) cm −1 tentatively assigned to ν(M‐S) in a trans configuration. [ 29–36 ] The IR spectra of trans ‐[Pd( k 1 ‐ S ‐ptt) 2 (SPPh 3 ) 2 ] ( 3 ) and trans ‐[Pd( k 1 ‐ S ‐ptt) 2 (OPPh 3 ) 2 ] ( 4 ) exhibit strong bands at 634 and 1010 cm −1 due to P=S [ 35 ] and P=O, [ 35 ] respectively (as shown in Figures S4, S7, and S10).…”

Section: Resultsmentioning

confidence: 99%

Optical properties, structural, and DFT studies of Pd(II) complexes with 1‐phenyl‐1H‐tetrazol‐5‐thiol, X‐ray crystal structure of [Pd(κ¹‐S‐ptt)₂(κ²‐dppe)] complex

Al‐Samra

Othman

et al. 2020

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Seven tetrazole‐thione complexes, [Pd2(κ2‐ptt)4](1), trans‐[Pd(k1‐S‐ptt)2(PPh3)2] (2), trans‐[Pd(k1‐S‐ptt)2(SPPh3)2] (3), trans‐[Pd(k1‐S‐ptt)2(OPPh3)2] (4), [Pd(k1‐N‐ptt)2(k2‐dppe)] (5a), [Pd(k1‐S‐ptt)2(k2‐dppe)] (5b), [Pd(k1‐S‐ptt)2(k2‐dppeS2)] (6), and [Pd(k1‐S‐ptt)2(k2‐dppeO2)] (7), were prepared from 1‐phenyl‐1H‐tetrazole‐5‐thiol (Hptt), with substituted phosphines. These complexes were investigated by CHNS analysis; infrared (IR), nuclear magnetic resonance (NMR) (1H and 31P), and ultraviolet–visible (UV–Vis) spectroscopy; and single‐crystal X‐ray data for 5b. In Complex 1, the ptt− ligand adopted μ2‐ k‐N, k‐S bridging mode to afford a dimeric complex, whereas in Complexes 2–4, 6, and 7, the ptt− was covalently coordinated via sulfur atom of the thiol group as a solo product. In contrast, in Complex 5, the ptt− ligand was bonded in a monodentate fashion through a deprotonated tetrazole ring nitrogen atom in isomer 5a or via a thiolato sulfur atom in isomer 5b. These linkage isomers were clearly shown in the 31P‐{1H} NMR. To explain the adoption of the ligand binding modes in Complexes 5a and 5b, geometry optimization calculations were carried out on two isomers. Very small differences of all molecular parameters were found between 5a and 5b isomers. This confirms the reason for obtaining two isomers. Also, theoretical studies are made for all compounds, and excellent agreement is obtained with experimental data. The direct band gap (Eg) values are equal to 2.88, 2.85, and 2.45 eV for Complexes 1, 2, and 4, respectively, revealing a semiconductor nature. The inhibition activity of Complexes 1–3, 5, and 8 were evaluated versus the growth of four types of bacteria in vitro. The complexes showed a good activity compared with free ligand and a standard antibiotic.

“…These were shifted to lower frequencies of that in the free ligands; this means that coordination of the amine took place through the endocyclic nitrogen atoms. [20,25,32,33,57] The PipDT ligand displayed two distinguishing bands within 941-972 and 995-1063 cm −1 due to ν(C-S) and ν(C S), respectively; the dithiocarbamate ligand displayed two characteristic bands compared with [M(κ 2 -PipDT) 2 ] {M II Zn, Pd} (showed one band) and indicated that the PipDT bonded as monodentate model to the M (II) ion through the sulfur atom. [7,10,58] The spectra also diplayed υ(M-N) within the 443-to 496-cm −1 range [50,59] and υ(M-S) bond within the 418-to 455-cm −1 range.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Antimicrobial, computational, and molecular docking studies of Zn (II) and Pd (II) complexes derived from piperidine dithiocarbamate

Kadhim

Al-Nassiry

et al. 2020

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Mixed ligand complexes of Zn (II) and Pd (II) have been prepared from piperidine dithiocarbamate (PipDT) and amine ligand {2,2′‐bipyridine (Bipy), 1,10‐phenanthroline (Phen), and 3‐aminopyridine (3Apy)} to afford complexes of the type [M(κ1‐PipDT)(κ2‐Bipy)] {MIIZn, Pd} (1,4), [M(κ1‐PipDT)(κ2‐Phen)] (2,5), and [M(κ1‐PipDT)(κ1‐3Apy)2] (3,6). The reaction of equivalent molar of sodium benzisothiazolinate (Nabit) or sodium saccharinate (Nasac) with cis‐[PdCl2(PPh3)2], followed by addition, sodium piperidine dithiocarbamate (NaPipDT) afforded complexes of the type trans‐[Pd(κ1‐PipDT)(κ1‐N‐bit)(PPh3)2] (7) and trans‐[Pd(κ1‐PipDT)(κ1‐N‐sac)(PPh3)2] (8). The obtained complexes were characterized by elemental analysis and spectroscopic techniques. The PipDT− was bonded as monodentate fashion via sulfur atom, whereas the diamine ligands were coordinated as bidentate chelating, while the 3Apy ligand bonded as monodentate mode through the nitrogen of heterocyclic ring. In complexes (7) and (8), the bit− and sac− ligand coordinated as monodentate through the nitrogen atom of heterocyclic ring. The antimicrobial activity of the complexes was tested. All the complexes showed moderate to good activity compared with standard antimicrobial. Moreover, the calculations of the density functional theory (DFT) were performed to estimate the thermal parameters, dipole moment, polarizability, and molecular electrostatic potential of the present complexes; in addition, Mulliken atomic charges of the complexes, total electron density (TED), electrostatic surface potential (ESP), lethal concentration (LC50), and docking studies as well as the descriptors of chemical reactivity were studied.