Estudo da versatilidade do bis(2-piridinil)ditelano em química de coordenação

Abstract

This present work describes the synthesis and characterization of 19 compounds derivatives from bis(2-pyridinyl)ditellane (oPy2Te2, oPy = 2-pyridinyl) and bis(5-trifluoromethyl-2-pyridinyl)ditellane (Tfpy2Te2, Tfpy = 5-trifluoromethyl-2-pyridinyl). Due to their different coordination sites hardness (N and Te), the simple change between metal centers hardness used in reaction with these ligands resulted in different types of compounds like zwitterionic aryltellurium(II) halides H(Tfpy)TeX2 (X = Cl (1) or Br (2)), coordination compounds [Co(oPy2Te2-κN,N’)X2] (X = Cl (3) or Br (4)), [Cu(oPy2Te2-κN1,Te2,N2’)X]2 (X = Cl (5) or Br (6)), [Cu(oPy2TeClO-κO,N,N’)ClO]2 (7), [Cu2(oPy2Te-κN,N’)(MeCN)Br2] (8), [Re(RTeCl)(PPh3)2(O)2Cl] (9) and (10), [Tc2(NO)2(oPy2Te2-κTe,N)(PPh3)2Cl4] (11), monometallic clusters [Cu(-TeoPy-κTe,N)]4 (12), [Hg4(Ph3P)2(-TeoPy)6X2] (X = Cl (13) or Br (14)), [Hg4(Ph3P)2(-TeoPy)6I2]DMF (15), [Hg8(-TeoPy)12SCl2]·5,25DMF (16), zwitterionic clusters [Hg8(-TeoPy)11,07(-TeoPyH)0,93 SBr2,93]·7,62DMF (17) and [Hg8(-TeoPy)11,17(-TeoPyH)0,83 SI2,83]·7,25DMF (18) and heterometallic clusters [HgAg4(PPh3)3(-TeoPy)3(μ3-TeoPy)3] (19). The obtained compounds had their structure evaluated by X-ray crystallography, Fourier-transform infrared spectroscopy, confocal Raman spectroscopy, heteronuclear magnetic resonance spectroscopy (1H, 13C, 19F, 31P, 99Tc, and 125Te), elemental analysis and other complementary analyzes. Optical band gap estimation by UV-Vis spectroscopy on solid state and theoretical calculations were performed. Based on the analyzed properties, compound [Co(oPy2Te2-κN,N’)Br2] (4) was tested as potential photocatalyst for gaseous hydrogen production from water splitting, showing good results in the initial tests.