Synthesis, characterization and structures of cadmium(II) and mercury(II) complexes with bis(dipiperidinylphosphino)methylamine dichalcogenides

The authors are grateful to the Tunisian Ministry of High Education and Scientific Research for financial support (LR99ES14) of this research.Two new bidentate phosphine dichalcogenide ligands of the type MeN(Pip2PE)2 [(Pip = piperidinyl; E = S ( 1 ) or Se ( 2 )] and their cadmium(II) and mercury(II) chloride complexes MCl2{MeN(Pip2PE)2} [M = Cd; E = S ( 3 ); Se ( 4 ) or M = Hg; L = S ( 5 ); Se ( 6 )] were prepared and characterized by elemental analysis, IR, multinuclear (31P, 77Se and 113Cd) NMR spectroscopy and single crystal X-ray analyses. Ligands 1 and 2 were found to adopt anti conformation structures in the solid state in which both P=E groups are trans to each other. Complexes 3 - 6 are comprised of one ligand coordinated in a bidentate fashion to the metal centre in a distorted tetrahedral arrangement [98.46(3)-121.24(4)°]. The P=S bond lengths of 1.999(15)-2.003(14) Å in the complex ( 3 ) are slightly elongated compared to those in free ligand [1.933(15)-1.950(14) Å]. The results are discussed and compared with closely related analogues.PostprintPeer reviewe

Synthesis and structural characterization of Zn2+, Cd2+ and Hg2+ complexes with tripyrrolidinophosphine chalcogenides

Authors are grateful to the Tunisian Ministry of High Education and Scientific Research for support [grant number: LR99ES14] and to the French Service for Cooperation and Cultural Action (SCAC) in Nouakchott, Mauritania for a scholarship to KE.Six new complexes of zinc(II), cadmium(II) and mercury(II) chlorides with tripyrrolidinophosphine chalcogenides of the types [MCl2(Pyrr3PE)2] (M = Zn, E = S (1) or E = Se (2); M = Cd, E = S (3) or E = Se (4)) and [{HgCl(Pyrr3PE)}2(µ-Cl)2] (E = S (5) or Se (6)) have been prepared in yields of 66-92% by reaction of the ligands with metal chloride in ethanol and characterized by 1H and 31P NMR, IR, elemental analysis, conductivity, and single crystal X-ray diffraction analysis. The results show that the complexes are pseudo-tetrahedral containing coordinated chloride ions. Interestingly, the X-ray studies reveal that while the title ligands produce dinuclear complexes with Hg, their Cd and Zn complexes are mononuclear. The tetrahedral bond angles vary from 85.69(5)° to 126.25(4)° in dinuclear complexes 5 and 6 and from 93.51(3)° to 117.38(3)° in mononuclear species 2-4. The E = S bond lengths are in the range 1.999(9)-2.198(2) Å. The coordination properties of the title ligands are discussed and compared to those obtained for their bulkier counterparts.PostprintPeer reviewe

Synthesis, spectroscopic, and structural characterization of new functionalized gem-bisphosphonate complexes of tin(IV) chloride

The authors are grateful to the Tunisian Ministry of High Education and Scientific Research and Technology for financial support of this researchBisphosphonates of the types X(P(O)(OEt)2)2 (X = CH2=C (1a), CNCH2CH (1b) and PhCH2NCH2CH (1c)) react with SnCl4 in anhydrous dichloromethane to produce the new tin(IV) adducts [SnCl4(1a)] (2a), [SnCl4(1b)] (2b) and [SnCl4(1c)] (2c) in 72-80% yields. These complexes were characterized using IR, multinuclear (1H, 13C, 31P, 119Sn) NMR spectroscopy, elemental analysis, and in one case by single crystal X-ray diffraction. The NMR data show that the bisphosphonate ligands are coordinated to the tin center in a bidentate fashion forming cis octahedral tin complexes. Furthermore, the X-ray structure of complex 2b reveals that the bisphosphonate ligand is coordinated in a bidentate manner to the metal center in a distorted octahedral arrangement with Sn-O-P bond angles in the range 135.95(16)–137.99(18)°. The P=O and Sn-O bond lengths of 1.495(3)-1.497(3) and 2.134(3)-2.146(2) Å, respectively are in the order expected for phosphonate tin(IV) complexes. The results are discussed and compared with closely related analogues.PostprintPeer reviewe

Rescue leadless pacemaker implantation in a pacemaker-dependent patient with congenital heart disease and no alternative routes for pacing

Congenital heart disease patients are considered a unique group of patients regarding their high risk of conduction abnormalities, whether de novo or surgically induced, and the challenges in both implantation and management of device related complications. We present a case of a pacemaker-dependent patient with congenital heart disease who experienced complications of both previous epicardial and transvenous pacing which rendered her a non-suitable candidate of both routes

Synthesis, characterization, and structural properties of mercury(II), cadmium(II) and zinc(II) tripiperidinophosphine chalcogenide complexes

We are grateful to the Tunisian Ministry of High Education and Scientific Research for support [grant number LR99ES14] and to the French Service for Cooperation and Cultural Action in Nouakchott, Mauritania for a scholarship to FE.Reaction of metal chlorides (MCl2) with tripiperidinophosphine chalcogenides (Pip3PE) produces new dimer species ( 1-6 ) of the formula [MCl2(Pip3PE)]2 (Pip = piperidinyl; E = S or Se; M = Hg, Cd or Zn). These coordination complexes were characterized by elemental analysis, IR, multinuclear (31P, 113Cd and 199Hg) NMR spectroscopy and single crystal X-ray analysis. Compounds 1-6 exist as centrosymmetric homobimetallic dimers, [M(µ-Cl)Cl(Pip3PE)]2. Each dimer incorporates two µ2-chloro atoms and two terminal M–Cl bonds. The E atom of Pip3PE forms terminal M–E bonds {S; 2.305(11); Se: 2.412(6)-2.589(15) Å} and thus the geometry about each metal centre is distorted tetrahedral and the range of tetrahedral bond angles is 102.83(3) to 113.32(3)o. The P=Se bond lengths of 2.183(9)-2.205(2) Å in the selenide complexes are slightly elongated compared to those in the free ligands [2.1090(4) Å]. The results are discussed and compared with those obtained for related analogues.PostprintPeer reviewe

Synthesis, characterization, structures, and DFT study of zinc(II) complexes with tributylphosphine chalcogenides

The authors are grateful to the Tunisian Ministry of High Education and Scientific Research for financial support (LR99ES14) of this research.Four new zinc(II) complexes of the type [ZnCl2(n-Bu3PE)2] (E = O ( 1 ), S ( 2 ), Se ( 3 ) or Te ( 4 )) have been synthesized from zinc(II) chloride and the ligands n-Bu3PE giving yields of 56-88%. The adducts were characterized by multinuclear (31P, 13C and 77Se) NMR, conductivity, IR spectroscopy and by X-ray analyses. The zinc complexes 1 – 4 are comprised of two ligands coordinated to the metal centre in a distorted tetrahedral arrangement. The P=E bond lengths of 1.497(7) (E = O), 2.000(4) (E = S) and 2.178(2) Å (E = Se) in these complexes are slightly elongated compared to those in the free ligand. In addition, a DFT/B3LYP theoretical study on the geometry optimization of the title ligands and their zinc complexes has been carried out in order to support and complement the experimental data and to further investigate the nature of the chalcogenide-metal interaction. The results show good agreement between the experimental and theoretical data.PostprintPeer reviewe

Tracking control of a nonholonomic wheeled mobile robot

This paper proposed a tracking control law for the kinematic model of the nonholonomic wheeled mobile robot (WMR). A Lyapunov candidate function is used to prove the stability of the controller. Simulation results verify the effectiveness of the proposed control law, where, a better path tracking of the mobile robot is achieved

Trajectory tracking of steering system mobile robot

In this paper, the kinematic model of nonholonomic differential wheeled mobile robot steering system is established. Based on the model, a nonlinear feedback path tracking controller is proposed, which causes the closed loop system state equation for the robot to have equilibrium condition at the origin. Lyapunov candidate function is used to prove that the closed loop system is asymptotically stable at origin. Simulation results verify the usefulness of the tracking control approach