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king87

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About king87

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  1. Hi! i have to determine the association constant for host-guest inclusion complex... i have already the input file, and i imported data... but i am not sure what to do then? manual fitting? the refinement doesnt work...
  2. Is anyone using HypNMR?
  3. Is it possible to calculate binding constant manually for inlusion complex (binding host with guest), having just data for 1:0, 1:1 ratios (spectra)?
  4. Hello! I analise metal chemical shifts, and there is some trend: I > CN > Br > NH3 > NO2 > Cl > H2O, so, the metal signal shielding increase in order showed below... I noticed, the less electronegative and bigger halogen ion as ligand, the chemical shift of metal, like palladium, is more shielded. It is probably caused by backdonation of electrons from ligand towards metal. What about the other ligands? For example, NH3 is "less electronegative" ligand than H2O, so lone pair on nitrogen may donate electrons? bond metal-OH2 is more ionic probably, and electrons are shiftes slightly more to oxygen than metal... What about CN, NO2? What can be the effect of this trend? which properties of those ligands may influence chemical shift? it is usually influenced by donation/withdrawing of electrons and so on... polarizability?
  5. What are the differences between 1) Metal Organic Frameworks (MOFs), 2) Covalent Organic Polymers (COFs) and 3) Porous Organic Polymers (POPs)?? 2 are the same like 1, but there is no coordination bond just covalent bonds? 3 there is no metal atom? how to distinguish between such a similar species?
  6. what is the basicity of carbon: primary, secondary, tertiary, e.g. in 1-adamantylamine (C connected with N is connected also with 3 other C, 2-adamantylamine (with two other C), 1-adamantymmethylamine (with just one next carbon)? more carbons connected to this first carbon: ...-C-NH2 makes it less basic, or more?
  7. How would you define delocalization index? how in very easy way explain it to students who has no idea about that
  8. transition metal complexes, effect of ligands on metal NMR shift... complexes of formula M(amine)2X2, they write, that the difference between cis and trans isomers chemical shift, for dipiridine isomers (amine=piridine) is greater for diiodo than for dichloro complexes... and say if ligands amine and X are far from each other in the trans influence series, this difference chemical shift cis-trans is bigger... but why? wow it influence metal chemical shift? trans influenceof iodine is much larger than chlorine, so the Pt-N bond trans to iodine will be longer than when its trans to chlorine. but how it affects shielding of nmr signal? i would say its just withdrawal of electrons, why order in trans series affects that?
  9. Hi, why polarizability of ligand -OH2 is bigger than of -H? what is the polarizability of NO2 comparing to them and e.g. I? i know that for halogens, it increase with increase of size of halogen down the group (electrons have more space on bigger atom), but how it is with other ligands? Thank you.
  10. Hi, i have been wondering about the influence of the ligands on metal NMR shifts, for complexes with metal like Pd, the ligands are 2 amine ligands, and they have also two chlorides in structure, cis or trans geometry. In DMF, when comparing the difference between the chemical shifts of the same complexes (the same ligands) but with different geometry, for cyclic amines like cyclopropyl-cyclohexyl, is small, and trans-compounds signal are more shielded. The opposite situation is for ths type of coplex with NH3, MeNH2 or Adamantylamine ligands, trans more deshielded than cis, and the difference between cis and trans is biggest for adamantylamine compounds, while for rest is veeery small. What can be the reason? Greetings.