Dawit Tesfaye, Mamo Gebrezgiabher, Jonas Braun, Taju Sani, Abbasher Gismelseed, Tim Hochdörffer, Volker Schünemann, Juraj Kuchár, Juraj Černák, Christopher E. Anson, Madhu Thomas and Annie K. Powell
{"title":"乙二胺不对称铁(iii)席夫碱配合物的自旋交叉行为","authors":"Dawit Tesfaye, Mamo Gebrezgiabher, Jonas Braun, Taju Sani, Abbasher Gismelseed, Tim Hochdörffer, Volker Schünemann, Juraj Kuchár, Juraj Černák, Christopher E. Anson, Madhu Thomas and Annie K. Powell","doi":"10.1039/D4NJ03532A","DOIUrl":null,"url":null,"abstract":"<p >Novel asymmetrical Fe(<small>III</small>) Schiff base coordination complexes, with the N<small><sub>4</sub></small>O<small><sub>2</sub></small> coordination environment, exhibiting abrupt spin crossover (SCO) behaviour with a wide hysteresis loop of 27 K, have been synthesised from an ethylenediamine based asymmetrical Schiff base ligand <em>viz. N</em>-(2-aminoethyl)salicylaldimine (saen) and characterised <em>via</em> single crystal XRD measurements, variable temperature magnetic studies and Mössbauer measurements. The single crystal XRD measurements prove that the compound is a mixture of two fractions, one with methanol and the other without methanol, <em>viz</em>, [Fe(saen)<small><sub>2</sub></small>]NO<small><sub>3</sub></small>·CH<small><sub>3</sub></small>OH at 299 K (<strong>1–299</strong>) and at 173 K (<strong>1–173</strong>) and [Fe(saen)<small><sub>2</sub></small>]NO<small><sub>3</sub></small> at 173 K (<strong>2–173</strong>), confirming that the Fe(<small>III</small>) centre has a distorted octahedral coordination geometry having two deprotonated asymmetrical tridentate saen ligands, counterbalanced by a nitrate anion and methanol solvent molecule in <strong>1</strong> while <strong>2</strong> has a non-solvate form. An extended hydrogen bonding network between the amino hydrogen atoms of the saen ligand, nitrate counteranion, and methanol solvate molecule is observed in fraction <strong>1</strong>, while an extended zig-zag hydrogen bonding between the nitrate anion and amino hydrogens of saen is observed in fraction <strong>2</strong>. Furthermore, the complex has been characterised by variable temperature magnetic susceptibility measurements and <small><sup>57</sup></small>Fe Mössbauer spectroscopy, confirming the SCO nature.</p>","PeriodicalId":95,"journal":{"name":"New Journal of Chemistry","volume":null,"pages":null},"PeriodicalIF":2.7000,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Spin crossover behaviour of asymmetrical iron(iii) Schiff base complexes from ethylenediamine†\",\"authors\":\"Dawit Tesfaye, Mamo Gebrezgiabher, Jonas Braun, Taju Sani, Abbasher Gismelseed, Tim Hochdörffer, Volker Schünemann, Juraj Kuchár, Juraj Černák, Christopher E. Anson, Madhu Thomas and Annie K. Powell\",\"doi\":\"10.1039/D4NJ03532A\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Novel asymmetrical Fe(<small>III</small>) Schiff base coordination complexes, with the N<small><sub>4</sub></small>O<small><sub>2</sub></small> coordination environment, exhibiting abrupt spin crossover (SCO) behaviour with a wide hysteresis loop of 27 K, have been synthesised from an ethylenediamine based asymmetrical Schiff base ligand <em>viz. N</em>-(2-aminoethyl)salicylaldimine (saen) and characterised <em>via</em> single crystal XRD measurements, variable temperature magnetic studies and Mössbauer measurements. The single crystal XRD measurements prove that the compound is a mixture of two fractions, one with methanol and the other without methanol, <em>viz</em>, [Fe(saen)<small><sub>2</sub></small>]NO<small><sub>3</sub></small>·CH<small><sub>3</sub></small>OH at 299 K (<strong>1–299</strong>) and at 173 K (<strong>1–173</strong>) and [Fe(saen)<small><sub>2</sub></small>]NO<small><sub>3</sub></small> at 173 K (<strong>2–173</strong>), confirming that the Fe(<small>III</small>) centre has a distorted octahedral coordination geometry having two deprotonated asymmetrical tridentate saen ligands, counterbalanced by a nitrate anion and methanol solvent molecule in <strong>1</strong> while <strong>2</strong> has a non-solvate form. An extended hydrogen bonding network between the amino hydrogen atoms of the saen ligand, nitrate counteranion, and methanol solvate molecule is observed in fraction <strong>1</strong>, while an extended zig-zag hydrogen bonding between the nitrate anion and amino hydrogens of saen is observed in fraction <strong>2</strong>. Furthermore, the complex has been characterised by variable temperature magnetic susceptibility measurements and <small><sup>57</sup></small>Fe Mössbauer spectroscopy, confirming the SCO nature.</p>\",\"PeriodicalId\":95,\"journal\":{\"name\":\"New Journal of Chemistry\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.7000,\"publicationDate\":\"2024-09-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"New Journal of Chemistry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.rsc.org/en/content/articlelanding/2024/nj/d4nj03532a\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Journal of Chemistry","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/nj/d4nj03532a","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
Spin crossover behaviour of asymmetrical iron(iii) Schiff base complexes from ethylenediamine†
Novel asymmetrical Fe(III) Schiff base coordination complexes, with the N4O2 coordination environment, exhibiting abrupt spin crossover (SCO) behaviour with a wide hysteresis loop of 27 K, have been synthesised from an ethylenediamine based asymmetrical Schiff base ligand viz. N-(2-aminoethyl)salicylaldimine (saen) and characterised via single crystal XRD measurements, variable temperature magnetic studies and Mössbauer measurements. The single crystal XRD measurements prove that the compound is a mixture of two fractions, one with methanol and the other without methanol, viz, [Fe(saen)2]NO3·CH3OH at 299 K (1–299) and at 173 K (1–173) and [Fe(saen)2]NO3 at 173 K (2–173), confirming that the Fe(III) centre has a distorted octahedral coordination geometry having two deprotonated asymmetrical tridentate saen ligands, counterbalanced by a nitrate anion and methanol solvent molecule in 1 while 2 has a non-solvate form. An extended hydrogen bonding network between the amino hydrogen atoms of the saen ligand, nitrate counteranion, and methanol solvate molecule is observed in fraction 1, while an extended zig-zag hydrogen bonding between the nitrate anion and amino hydrogens of saen is observed in fraction 2. Furthermore, the complex has been characterised by variable temperature magnetic susceptibility measurements and 57Fe Mössbauer spectroscopy, confirming the SCO nature.