Svinčeve koordinacijske spojine z nekaterimi tiosemikarbazidi kot ligandi

Erhatič, Jerneja (author), Pevec, Andrej (mentor)

Sintetizirala sem nove svinčeve koordinacijske spojine. Pri sintezi sem kot liganda uporabila dva tiosemikarbazida, 4-(2-piridil)tiosemikarbazid (L1) in 4-(6-metil-2-piridil)tiosemikarbazid (L2). Vse reakcije sem izvedla po enakem postopku. Kot topilo sem uporabila raztopino metanola in zmes refluktirala. Po končanih reakcijah sem omogočila počasno odparevanje topila pri sobnih pogojih. Izločilo se je pet produktov (1–5). Nastale strukture sem okarakterizirala s pomočjo rentgenske strukturne analize. Spojini 1 in 2 sta kristalni strukturi uporabljenih ligandov. Nastala je nova kristalna struktura liganda L1, ki še ni opisana v literaturi. Posneta sta bila tudi IR in 1H NMR spektra. Prav tako v literaturi ni opisana kristalna struktura liganda L2. Kristalna struktura spojine 3 ima formulo [Pb(L1)4(SCN)2]·2CH3OH. Centralni ion je svinčev(II) ion, ki ima koordinacijsko vezanih šest ligandov. Koordinacijsko število svinca je osem, s popačeno strukturo dodekaedra. Dva liganda L1 sta na centralni ion vezana kelatno preko atoma dušika in žvepla, dva pa monodentatno preko atoma žvepla. Koordinacijsko se vežeta tudi dva tiocianatna iona. Posneta sta bila IR in 1H NMR spektra. Spojini 4 je bila določena kristalna struktura s formulo [Pb(L1)4(NO3)2]·2CH3OH, ki je podobna kristalni strukturi spojine 3. Šest ligandov je vezanih na centralni svinčev(II) ion s koordinacijskim številom osem v obliki dodekaedra. Dva liganda L1 sta na svinčev(II) ion vezana monodentatno preko atoma žvepla, dva pa kelatno preko atomov dušika in žvepla. Vežeta se tudi dva nitratna iona. Kristalna struktura spojine 5 s formulo [Pb2(L2)6(NO3)2](NO3)2·2H2O je koordinacijski kompleks. Nastal je koordinacijski kation, ki ima dva svinčeva(II) iona. Na vsak svinčev(II) ion so kelatno vezani trije ligandi L2 in monodentatno en nitratni anion. Koordinacijsko število posameznega svinčevega(II) iona je osem. V celotni strukturi sta dva L2 tudi mostovna liganda, ki povezujeta svinčeva(II) iona preko atoma žvepla.

• Language: Slovenian
• Keywords: koordinacijske spojine, svinec, tiosemikarbazidi, kelatni ligand
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2021
• PID: 20.500.12556/RUL-127461
• COBISS.SI-ID: 66774275
• Publication date in RUL: 08.06.2021

Secondary language

• Language: English
• Title: Lead coordination compounds with some thiosemicarbazides as ligands

Abstract

New lead coordination compounds were synthesised. Two thiosemicarbazides were used, 4-(2-pyridyl)thiosemicarbazide (L1) and 4-(6-methyl-2-pyridiyl)thiosemicarbazide (L2). Reactions were carried out under the same procedure. Methanol was used as a solvent. The solutions were under reflux. Slow evaporation of solvent was carried out under ambient conditions. Five products (1–5) were isolated. New products were characterised using single crystal X-ray diffraction. Compounds 1 and 2 are crystal structures of used ligands, respectively. New crystal structure of ligand L1 was formed, which has not yet been characterised in literature. IR and 1H NMR spectra were taken. Crystal structure of ligand L2 has not yet been characterised in literature as well. Crystal structure of compound 3 with the chemical formula [Pb(L1)4(SCN)2]·2CH3OH was characterised. Central ion is lead(II) ion with coordinated six ligands. Coordination number of lead is eight with distorted dodecahedron structure. Two ligands L1 form a chelate ring through nitrogen and sulphur atoms and two L1 are monodentatly coordinated through sulphur atom. Two thiocyanate ions are coordinated. IR and 1H NMR spectra were taken. Crystal structure of compound 4 was characterised with the chemical formula [Pb(L1)4(NO3)2]·2CH3OH, similar to crystal structure of compound 3. Six ligands are coordinated to lead(II) central ion with coordination number eight in shape of dodecahedron. Two ligands L1 form a chelate ring through nitrogen and sulphur atoms and two L1 are monodentatly coordinated through sulphur atom. Two nitrate ions are coordinated. Crystal structure of compound 5 was characterised with the chemical formula [Pb2(L2)6(NO3)2](NO3)2·2H2O. Coordination cation was formed containing two lead(II) ions. Each central ion has three coordinated L2 and one monodentatly coordinated nitrate ligand. Coordination number of each lead(II) ion is eight. Two chelate L2 are also bridging ligands that form a bridge through sulphur atom between both lead(II) ions.

• Keywords: coordination compounds, lead, thiosemicarbazides, chelate ligand