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Herein we describe the synthesis of a library of new mercury complexes, including some dimers and polymeric species. Initially, a phosphonium salt, [PPh3CH2C(O)C6H4–m-OCH3]Br (S), was synthesized from triphenylphosphine (PPh3) and BrCH2C(O)C6H4-m-OCH3 in acetone. We then reacted this phosphonium salt with an appropriate base to acquire a new phosphorus ylide monodentate, PPh3=C(H)C(O)C6H4-m-OCH3 (Y). Finally, we treated the synthesized ligand with mercury halides in dry CH3OH to form C-coordinated complexes of the form [HgX(PPh3C(H)C(O)C6H4-m-OCH3) (μ-X)]2 [X = Cl (1), Br (2), I (3)], [(PPh3=C(H)C(O)C6H4-m-OCH3)Hg(NO3)2]n (4). We characterized these compounds using CHN analysis, FT-IR, NMR (1H, 13C and 31P) and density functional theory. We elucidated the structure of 2 by single-crystal X-ray diffraction. The results establish that 1, 2 and 3 have dimeric structures, while a polymeric structure is suggested for 4. The antioxidant activity of all compounds in DMSO was assessed using a DPPH free radical scavenging method. Also, the nature of metal-ligand (C→Hg) bonding in 1, 2 and 3 have been investigated using natural bond orbital (NBO) and energy-decomposition analyses (EDA). [ABSTRACT FROM AUTHOR]

The new unsymmetrical phosphonium salts [Ph2PCH2PPh2CH2C(O)C6H4R]Br (R= m-Br (S1) and p-CN (S2)) were synthesized in the reaction of 1,1-bis(diphenylphosphino)methane (dppm) and BrCH2C(O)C6H4R (R= m-Br and p-CN) ketones, respectively. Further treatment with NEt3 gave the α-keto stabilized phosphorus ylides Ph2PCH2PPh2C(H)C(O)C6H4R (R= m-Br (Y1) and p-CN (Y2)). These ligands were reacted with [MCl2(cod)] (M= Pd and Pt; cod= 1,5-cyclooctadiene) to give the pallada- and platinacycle complexes [MCl2(Ph2PCH2PPh2C(H)C(O)C6H4R)] (M= Pd, R= m-Br (3); R= p-CN (4) and M= Pt, R= m-Br (5); R= p-CN (6)). Cyclic voltammetry, elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopic methods were used for characterization of the obtained compounds. Further, the structure of complexes 3 and 4 were characterized crystallographically. Palladacycles 3 and 4 were proved to be excellent catalysts for the Suzuki-Miyaura coupling reactions of various aryl chlorides and arylboronic acids in mixed DMF/H2O media. Also, the bonding situations between two interacted fragments [PtCl2] and Y1 and Y2 ligands in platinacycles 5 and 6 were investigated based on DFT method by using NBO, EDA and ETS-NOCV analysis. [ABSTRACT FROM AUTHOR]

Graphical abstract Two mononuclear Pd/Pt complexes with new bidentate carbon donor ligand have been synthesized. All newly synthesized compounds were characterized by X-ray analysis and physicochemical and spectroscopic data. Theoretical study on the structure of all complexes was investigated. Cytotoxic activity of all complexes has been performed. Abstract The new phosphonium salt, the C,C-chelating phosphorus ylide ligand, (MeOC 6 H 5 C(O)CH PPh 2 (CH 2) 2 PPh 2 CHC(O)C 6 H 5 OMe), and its Pd(II) and Pt(II) complexes have been synthesized and the cytotoxic activity of the synthesized complexes against three human cancer cell lines, including HeLa (Human cervix cancer cell line), KB (human oral cancer cell line) and U87 MG (human glioblastoma cell line) were evaluated using an MTT assay. The new compounds were identified and characterized using multinuclear (1H, 13C and 31P) NMR, infrared (IR) spectroscopy, elemental analysis, and through UV absorption and fluorescence emission spectra. Also, the crystal structure of the phosphorus ylide ligand was determined by single-crystal X-ray diffraction analysis. According to the obtained results from the MTT assay, the Pd(II) and Pt(II) complexes demonstrated a higher cytotoxic activity against KB human oral cancer cells in comparison with other cell lines, rendering these compounds into suitable candidates for further anti-oral cancer studies. Furthermore, a theoretical study on structure and nature of the M C bonding between the Y ligand (ylide) and MCl 2 fragment in the [YMCl 2 ] (M = Pd, Pt and Y = (MeOC 6 H 5 C(O)CH PPh 2 (CH 2) 2 PPh 2 CHC(O)C 6 H 5 OMe)) complexes have been reported via NBO and energy-decomposition analysis (EDA). [ABSTRACT FROM AUTHOR]

Abstract The dehydrobromination reaction of a new sulfonium salt [(Me) 2 SCH 2 (O)C 10 H 7 ]Br (1) with sodium hydroxide solution led to formation of sulfonium ylide (Me) 2 SCHC(O)C 10 H 7 (2) which was used to synthesize three binuclear complexes [{(Me) 2 SCHC(O)C 10 H 7 } 2 HgX 2 ] 2 (X = Cl (3), Br (4) and I (5)). Characterization of all compounds was thoroughly performed by elemental analysis, IR, 1H and 13C NMR spectroscopic methods. Also the structure of complex (4) was characterized by X-ray crystalography methode. The structure of prepared complexes was also compared with analogous phosphonium complexes [{Ph 3 PCHC(O)C 10 H 7 } 2 HgX 2 ] 2 (X = Cl, Br and I) using DFT calculations with the M06/def2-SVP level of theory. Based on the theoretical studies of geometry-optimized bidentate structures, the interaction energy values, ΔE int , for C→M bonds in [{(Me) 2 SCHCOC 10 H 7 }HgX 2 ] 2 complexes are larger than those in [{Ph 3 PCHCOC 10 H 7 }HgX 2 ] 2 (X = Cl, Br and I) complexes. Obviously, in comparison to the phosphonium ylide, the sulfonium ylide forms a stronger bond with Hg 2 X 4 (X = Cl, Br and I) fragments in aforementioned complexes. Graphical abstract Image 1 Highlights • Sulfonium ylides were C-coordinated from ylidic carbon to Hg center. • Binuclear structure of Hg(II) sulfonium ylide complexes has identified by X-ray crystallography method. • Sigma interactions are very important in both binuclear Hg(II) sulfonium and phosphonium ylide complexes. • In comparison to the phosphonium ylide, the sulfonium ylide forms a stronger bond with Hg 2 X 4 fragment. • The value of C M bond lengths in Hg(II) sulfonium and phosphonium ylide complexes is dependent on ylide types and X atoms. [ABSTRACT FROM AUTHOR]

Phosphonium salts [Ph 2 PCH 2 CH 2 PPh 2 CH 2 C(O)C 6 H 4 - m -R]Br (R = Br ( 1 ) and OCH 3 ( 2 )) were synthesized from the reaction of 1,1-bis(diphenylphosphino)ethane (dppe) and 2,3ʹ-dibromoacetophenone and 2-bromo-3′-methoxyacetophenone, respectively. Treatment with NEt 3 gave the corresponding α-keto stabilized phosphorus ylides Ph 2 PCH 2 CH 2 PPh 2 C(H)C(O)C 6 H 4 - m -R (R = Br ( 3 ) and OCH 3 ( 4 )). Reaction of these ylides with C 60 and dimethylacetylenedicarboxylate (DMAD) led to the formation of the new [6,6]-methanofullerene derivatives {C 60 .DMAD.Ph 2 PCH 2 CH 2 PPh 2 C(H)C(O)C 6 H 4 - m -R} (R = Br ( 5 ) and OCH 3 ( 6 )) bearing both α-keto and α, β-ester stabilized phosphorus ylides. These [6,6]-methanofullerene derivatives were highly soluble in conventional organic solvents such as toluene, chloroform, dimethyl sulfoxide (DMSO), N , N -dimethylformade (DMF), N -methyl-2-pyrrolidinone (NMP) and even partially soluble in ethanol and acetone. All compounds were characterized by IR, UV–Vis, ESI-MS, 1 H, 13 C, DEPT-135 and 31 P NMR spectroscopic methods. The structure of the phosphine oxide derivative of compound 4 was characterized by single crystal X-ray crystallography. The electronic and molecular structure of compound 5 has been investigated at the BP86/def2-SVP level of theory. The nature of the C P bond in this compound was also analyzed with charge and energy decomposition methods. Compounds 5 and 6 were subjected to antioxidant activity screening by 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging assay. The results from these experiments showed that the compounds possess strong antioxidant activity (IC 50 ; 0.890 ± 0.004 to 1.081 ± 0.010 mg/ml). [ABSTRACT FROM AUTHOR]

New symmetrical p -CN-C 6 H 4 C(O)CH 2 PPh 2 (CH 2) 2 PPh 2 CH 2 C(O)C 6 H 4 - p -CN]Br 2 (1) and unsymmetrical [PPh 2 (CH 2) 2 PPh 2 CH 2 C(O)C 6 H 4 - p -CN]Br (2) phosphonium salts were prepared by reacting Bis(diphenylphosphino)ethane (dppe) with p -CN-C 6 H 4 C(O)CH 2 Br in acetone, in 1:2 and 1:1 ratios, respectively. Treatment of these salts with an appropriate alkali led to symmetrical p -CN-C 6 H 4 C(O)C(H)PPh 2 (CH 2) 2 PPh 2 C(H)C(O)C 6 H 4 - p -CN (3) and unsymmetrical PPh 2 (CH 2) 2 PPh 2 C(H)C(O)C 6 H 4 - p -CN (4) ylides.The reaction of 3 and 4 with [MCl 2 (cod)] (M = Pd or Pt; cod = 1,5-cyclooctadiene) in 1:1 ratio, using dichloromethane as a solvent, led to mononuclear seven membered metallocyclic ring complexes ([MCl 2 (p -CN-C 6 H 4 C(O)C(H)PPh 2 (CH 2) 2 PPh 2 C(H)C(O)C 6 H 4 - p -CN)] (M = Pd (5) and Pt (6) , having C,C coordination mode) and mononuclear six membered ring complexes [MCl 2 (PPh 2 (CH 2) 2 PPh 2 C(H)C(O)C 6 H 4 - p -CN)] (M = Pd (7) and Pt (8) , having P,C coordination mode), respectively. Characterization of the resulting compounds were performed by elemental analysis, IR, 1H,13C and 31P NMR spectroscopic methods. As well, the unequivocal structure of compound 5 (seven membered pallada-cycle complex) was characterized crystallographically. In the symmetrical complexes, with seven membered metallocyclic rings, the title ylide is coordinated to the metal through two ylidic carbon atoms. Using theoretical methods, Density-function theory (DFT) calculations at the BP86/def2-SVP level of theory, the structures of the unsymmetrical six membered pallada- and platinacyclic complexes were compared with the structures of the symmetrical seven membered pallada- and platinacyclic complexes. The strength and nature of donor − acceptor bonds between the phosphorus ylide (Y ligand) and MCl 2 fragments in the [YMCl 2 (M = Pd, Pt, Y = p -CN-C 6 H 4 C(O)C(H)PPh 2 (CH 2) 2 PPh 2 C(H)C(O)C 6 H 4 - p -CN,PPh 2 (CH 2) n PPh 2 C(H)C(O)C 6 H 4 - p -CN, n = 1–2, were carried out by Natural bond orbital analysis (NBO) and energy-decomposition analysis (EDA) as well as their natural orbitals for chemical valence (NOCV) variations. Image 1 • Four mononuclear pallada- and platinacyclic complexes of phosphorus ylide have been synthesized. • All newly synthesized complexes were characterized by spectroscopic data. • The structure of one of Pd complexes was recognized by X-ray crystallography technic. • Theoretical study on the structure of all complexes was investigated. • Two types of coordination, (C, P) and (C, C) coordination mode, in phosphorus ylide complexes was compared. [ABSTRACT FROM AUTHOR]