Organometallic Chemistry - Science topic

Hi!

d10-d10 interactions are nifty and do exist. A quick search brings up this review on the topic: https://pubs.rsc.org/en/content/articlelanding/2011/cs/c0cs00102c/unauth

Looks like that and a forward search would be a good place to start to see what's out in the literature.

Good luck!

Thermodynamics.

Lol, yeah I get you meant specifics. I would be curious to see if DFT could tease out what's going on.

Reference for the chemistry?

Dear Gabrielle Davis ,

Maybe these articles are useful for you:

Hope this helps!

I think that your complex is noninnocent low-spin CoII–corrole•2– electronic configuration. Either convert your cobalt corrole to bis(pyridine) hexacoordinated complex to get diamagnetic NMR or measure NMR in Pyridine-d5 solvent.

Some possible explanations:

1. Initial guess: The initial guess for the TS calculation is crucial. Even though you used the optimized structures from the scan calculation, it's possible that the initial guess for the TS calculation is not accurate enough. You might consider providing a better initial guess, such as manually modifying the coordinates to bring the molecules closer together or using interpolation methods to generate an intermediate structure between the reactant and product.

2. Convergence criteria: The default convergence criteria for TS calculations in Gaussian might not be stringent enough for your system. You could consider tightening the convergence criteria by specifying tighter optimization and frequency convergence thresholds using the `Opt` and `Freq` keywords, respectively.

3. Constraints: It's important to ensure that the necessary constraints are properly imposed during the TS calculation. Constraints, such as freezing specific bonds or angles, can help guide the optimization towards the desired transition state. You might need to review and adjust the constraints you're using for the TS calculation.

4. Noeigentest: The `noeigentest` keyword can be used to disable the eigentest in Gaussian, which can improve stability in some cases. However, it's generally recommended to use the `noeigentest` keyword primarily for smaller systems. For larger systems with 84 atoms, the eigentest is usually beneficial for stability and convergence. Therefore, it's advisable to include the `noeigentest` keyword for the TS calculation.

5. Method and basis set: The choice of the computational method and basis set can affect the accuracy and convergence of TS calculations. You might consider using a higher level of theory or a different basis set to improve the results. Additionally, for catalytic reactions, it's often beneficial to use functionals or methods that are known to describe bond-breaking and forming processes accurately.

Hope it helps:credit AI

Dear Maryam,

The following articles may be of help to you. Of course, the M+2/M+3 ratio is essential but pH is critical since it will determine the solubility of the M(OH)2 or M(OH)3 phases.

1- Robertson J. Geochemical characteristics of aluminum and magnesium secondary mineral phases in uranium mill tailings. Ph.D. University of Saskatchewan. 2017.

See these previous discussions:

Applied Organometallic Chemistry

Yes of course

Dear Onyeka Stanislaus Okwundu thank you for sharing this very interesting chemical question with the RG community. As a synthetic inorganic chemistry I absolutely not an expert in this area of research. However, I at least found two literature references which at least come close to answering your question in part. Both describe the dehydrogention of cyclohexylamine under formation of aromatic amines. Please have a look at these articles:

and

The second paper is even freely available as public full text. You can find and access other related articles by searching the "Publications" section of RG for the term "dehydrogenative aromatization":

Other articles are found when searching for terms like "acceptorless dehydrogenative aromatization". When searching for literature references, I think you should better avoid the term "uncompromising" as in your original question. This word seems to be rather unusual in this context.

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

Dear J. Narayanan, this is clearly a question of great current interest and importance. I believe it is entirely up to you; there is no genuine consensus on the literature in my opinion. Some people use an abbreviation that highlights their university or place of origin (UiO, MIL, STAM, UMCM, SNU, DUT), while others merely use the formula unit (Fe2dobdc, Zn2bdc2dabco or [Fe2dobdc]n, [Zn2bdc2dabco]n). If the formula isn't too hard, I like to use the formula unit so that everyone knows what it is. However, how you name your MOF after publication is entirely up to you; as long as it makes sense, no referee should object.

I hope this gives you some useful initial information. Good luck with your research and best wishes!

This question intrigued me.

The compound you have in mind will not be aromatic. I tried it with phosphorous atoms. In this case you clearly have 2 lonepairs and no triplebond. Heavier atoms will probably be isolobal. Only if you block the p orbitals with additional substituents/ligands you can force electrons to use higher orbitals. Anyway your multiple bond is then constructed with delta-orbitals or even more exotic.

Another aspect is, that you have to consider canonical MOs. They will not be restricted to one of the 2 rings (its a question of the pricipal axis)

I have attached you a file containing a NICS analysis where I compared your compound with the vogel aromat (methano[10]annulene). Also the HOMOs are included. You can clearly see, that your compound, if existing, would be antiaromatic and the HOMO is completly delocalised.

For the calculations I used B3LYP/6-31G(d,p) with g09

Please check the following free document. My Regards

Hi, what do you mean by "got cleaved"? Did you get deprotected B(OH)2 or deboronation product? Thanks!

Dear all, attached is a book dealing with tips and practices in manipulating air sensitive chemicals. Under the circonstances you want to work, the best option is to work with a continuous lab flow reactor. Please check the link below. My Regards

Thank you Frank T. Edelmann

Indeed I used 15 years ago meta orto and para. dicarbadodecaborane

However I used as a powder precursor and I got a lot of C within the films. I will try it in toluene

Srividya Swaminathan d-d transitions are symmetry forbidden (Laporte selection rule), and therefore less intense. MLCT (or any charge transfer) transitions are far more intense. Typically, molar extinction coefficients for d-d transitions are in the range of 200-500 M-1 cm-1 whereas that for the MLCTs is >1000 M-1cm-1.

Almost all ligands are sigma donor, though the extent of donation varies from ligand to ligand. Now the question is when a ligand will act as a pi acceptor or donor. Pi donor ligands are those which have extra non bonding electrons in their valence orbitals (simple example iodine). Now the extent of pi donation depends on the symmetry and energy of those orbitals. The energy difference between vacant metal orbitals and filled ligand orbitals should not be very high and both must have same symmetry. Now to be a pi acceptor a ligand needs to have an empty orbital and here too the extent of pi accepting tendency depends on the energy difference and symmetry of the empty ligand orbital and filled metal orbital.

ref: The Organometallic Chemistry of the Transition Metals by Robert H. Crabtree

Try a solution of elemental sulfur in Toluene or some sulfur compund if it is only important to get rid of the THF-ligand. Metal-Sulfur-bonds are quite favored. If it is important to get a free coordination site, you could try lyophilizing (freeze drying) the solution of the sample. Good luck! P.S.: I worked with a Mn/Re-THF-system + sulfur in my thesis.

Hi Abdulrahman Moursy Mahgoub, please find attached the Supplementary Information of the Tetrahedron Letters paper to give you some more detailed information. The authors use a number of substituted heterocycles as starting materials for the Heck coupling, but they are all neutral. However, they use DMF as solvent. Chances are that your p-chloropyridiniumchloride is soluble in DMF. So you should just give it a try and run a test reaction on a small scale. Good luck!

We routinely metalated 1,4-bis(trimethylsilyl)-2,5,7-cyclooctatriene with n-butyllithium and the TMS groups always remained unchanged.

The anhydrous RuCl3 is chemically inert and has very low solubility to most of the solvents.

You may find an answer here:

Dear Athar

What kind of error you are getting. Or you may send me the input file.

Hi. Here is an example of an input using multiple basis set:

#N B3LYP/gen pseudo=read OPT

name of the complex

1 1

C O H 0 6-311+G(2d,p) **** Re 0 sdd **** blank line Re0 sdd blank line

Obviously the blank line means you leave the line empty.

I don't know why but the gaussian input of these type must have two blank lines at the end.

There is no simple rule in tuning the emission of Pt(II) complexes. Every ligand system is different. What one should consider is whether that (electron-rich) group is placed on a moiety acting as HOMO or LUMO. Usually F is added to the phenyl ring of a cyclometalating ligand to increase the emission energy of the metal complex. But the following paper shows that addition of F to a phenyl ring can lead to red shift. The degree to which the emission is affected also depends on the substitution pattern.

Apart from this, usually we take it for granted that extending the conjugation of a ligand will lead to redshift in emission. But there are also exceptions:

Thank you very much for your answers, it helped a lot!

you can read .... it will help you 

I vote "to". The others seem less accurate or direct.

Thanks Dr. Bojidarka B. Ivanova. I know Chromatography is method for separation. It does not provide structural information about fragment ions. My main interest is in the Mass Spectroscopy. The compound in question is pure but I don't have access to only MS, thanks.

Thanks Dr. Fatma Ulusal. But I dont have access to only MS. I only have access to GC-MS and LC-MS..........................

Mr. Tom,

You could pay attention to Gaussian's manual and the reference section (http://gaussian.com/techsupport/, http://gaussian.com/references/). There are given even test files (http://gaussian.com/testjobs/).

In addition, inputs can be found here:

http://www.chem.tamu.edu/rgroup/lucchese/ePolyScat.E2.manual/TestsREADME.html 

by phase extraction( adding a miscible solvent like acetone) or by adding a salt i think 

what method do you suggest? I attempted to separate on a silica column but the complex was not collected

Hi,

If you know the geometry you can get it. Pt(IV) is octahedral, whereas Pt(II) is square planar. 

You can use 195Pt NMR if you have access to it and someone with experience doing it (it has a large spectral window). 

FYI oxidations from Pt(II) to Pt(IV) usually require a decent oxidant. Oxygen only works for very electron-rich Pt(II) complexes (ex: Pt(bpy)Me2, but not Pt(bpy)Cl2). If you put Pt(II) in, it's probably still Pt(II) unless there was a good oxidant (eg. Cl2, R-I, H2O2) in there. 

If your compound has a Pt-P bond, you can see the coupling constant in the 13P NMR. Generally if it is less than 2000, it is Pt(IV), but if it is more than 2000 it is Pt(II). It depends on the ligands, though.

-Kyle

Mr. Rao,

You could pay attention to:

1. ChemPhysChem, 14, 2013, 311-314, Electrochemically controlled proton-transfer-catalyzed reactions at liquid-liquid interfaces: Nucleophilic substitution on ferrocene methanol, Peljo, P. et al.

2. Tetrahedron, 62, 2006, 9038-9042, Unexpected reactions of ferrocene acetal derived from tartaric acid with alkyllithium: competition between proton abstraction and nucleophilic attack, Zhang, W. et al.

I'm not an expert for SQUID magnetometry, but I'm not sure if this is possible with liquids, at least I have only used solids for SQUID. As antiferromagnetic coupling should require very low temperatures, you will have a frozen solution at this point. This would not really be a solution anymore, so you could as well do measurements in solid state. Furthermore, if you have a large quantity of diamagnetic frozen solvent and dilute paramagnetic analytes, this will probably not be very helpful in SQUID measurements, depite the sensitivity. Preparing the samples in an inert gas glovebox should not be a problem.

However, if you are interested in the magnetic properties in (still liquid) solution, I can recommend using an NMR based approach which was proposed by Evans. This is fairly standard and will work with any NMR spectrometer. You can find some information in the linked publications.

Aldehydes undergo nucleophilic addition reaction.

Yes........,  but , i asked  about its ability (application ) as anticancer  complexes or inhibition complexes 

Thanks all for the comments. Andreas, Yes! I was forgetting about this basic principle. 

Well, I'm studying a system with Ag nanoparticles and I was trying to add MV2+ but the chloride ions strongly react with the Ag nanoparticle. As was suggested hereI will try to use AgNO3. 

Dear Indranil,

You are asking about doing eom-ccsd? this is how to do so for two excited states and optimizing with respect to the 1st excited state, the states are singlets as am showing under the title after the 0 charge (neutral molecule) using 1, which is for singlet , for triplet states use 3 instead of 1

opt eomccsd=(nstate=2,root=1)

Title

0 1

But keep in your mind that eom-ccsd analytic gradients are only implemented in the recent Gaussian16 version, older versions will perform numerical gradients, which is extremely expensive

CDCs are a subset of C-H activation reactions. In general, C-H activation reactions proceed with the general form:

C–H + X–Y  —>  C–Y + H–X

If X = H, then the reaction is considered dehydrogenative.

 Dear Stefano,

Unfortunately, I have also close to 40 years of experience with 31P NMR. -:). The determination of the position of P-ligands on transition metals and of the configuration of the formed complexes were always in the focus of our research. If one includes all transition metals and all peculiar P-ligands, it is indeed difficult to set up a simple classification for cis-trans geometry, based solely on 2JPP.  However, as you also know it very well, triphenylphosphine complexes of late transition metals (including cis  and trans assignments) are among the most explored areas in 31P NMR spectroscopy. The range of cis and trans 2JPP of late transition metal complexes of triphenylphosphine, and more specifically, the analogous values for Ru complexes were suggested on this basis.  

Regards,  

                Imre

The J-coupling for trans is larger than that of  cis-isomer. IR will help you to see if it is cis or trans.

If I correctly understood the theme, Cu was not leached from solution but mainly from HKUST-1 net. This happens even without organic molecules interacting with Cu2+ ion, but merely with the presence of water media. If there are unstructured Cu2+ in the pores of the net, hence they should be displaced to the solvent phase through water/ethanol washings. But if you use adduct or chelating agents the scavenging of the metallic center from the net is driven through adduct, chelate or macrocyclic effect depending on the employed substance that interacts, with Cu in this case. Its own dissolution or coordinating assisted dissolution happens due to the fact that the HKUST-1 crystallites are surface open/labile materials containing -COOH, -COO- and -COOCu sides or functionalities directed to the interaction with the solvent. Therefore having these terminals, these components should displace to the media since Cu is efficiently solvated with water molecules. In this way the displacement of both Cu ions and trimesate or trimesic acid towards water is observed by UV-vis, therefore the loss of material is attained. Having less and larger crystals should diminish the dissolution rate, but if you have more and smaller crystals, the dissolution rate should be higher. I hope to be sufficiently clear in this explanation. If you need further details in order to understand the issue please contact me and looking forward to help in the analysis of your experiments. Best regards. Hiram

Hi...,

small amount of water can form milky color solution with ethanol therefore  You need to dry (purify) your ethanol and TTIP from water as much as possible avoid any water vapors before and during  making solution,and do not pass saturation limits.

Thank Hyun-Sue! Do you have any idea about the etching rate of each metal?

For inert atmosphere, argon is used  - it is heavy and replace air from vessels. SF₆ is also suitable, excluding work with alkali metals ( molten Mg and Al do not react). Powders should be degassed by 2-3x  pressure swing (vacuum-inert gas) .

As inert fluids you can use perfluorinated fluids, but they are reactive under milling with many metals, hydrides , metalorganics; hydrocarbon-based fluids (vaseline oil)  are reactive with oxidizers. For  mutual compatibility rough estimation  -  milling ball shock is equal to short-term 400^oC generation. 

Cryomilling (in  liquid nitrogen, LN2) do not have disadvantages of all above-mentioned mediums and is suitable for high energy materials milling; lab-scale equipment is available, but simple porcelain mortar and pestle are also functional

Do you actually mean PhPH₂ ?  If so, it oxidizes very quickly and should not be exposed to air.  If you mean Ph₃P, or triphenylphosphine, brief exposure is fine.

You can by choosen strong  ligand more than ammine

Thioamides are better ligands and more likely to cleave than amides. The Ru could activate the thioamide to nucleophilic attack by solvent or adventitious water if you in a non-aqueous solution. 

More reduced states open the door for closer distances between the metal atoms. Higher order bonds require the metals to be in very low oxidation states so they can get very close to each other. Moreover, lower oxidation states result in larger orbitals which allows them to have a much better overlap.

Additionally, we can use very bulky ligands to protect such bonds. 

For the compound to act as a chelating ligand, it would ideally have two donor atoms positioned in such a way that when both atoms bind to a metal, a five- or six-membered ring is formed e.g. 2,2`-bipyridine binds to a metal to form a 5 membered C-N-M-N-C-C ring, while acac binds to metals to give a 6 mebered C-C-O-M-O-C-C ring.

Does this help?

The change of colour from light to dark is due to the removal of the axial ligand (ethanol, DMF or water) from the copper acetate lantern, then the dark to light colour change is due to atmospheric water binding onto this coordination site. I find it's a good way to visually identify whether the activated samples have been exposed to air.

At 110 degrees Celcius, HKUST-1 should not have degraded, but it is worth checking by PXRD anyway. I have never done this desolvation when the sample wasn't under vacuum, so I'm not sure whether the air interacts with HKUST-1 at these comparatively low temperatures.

what functional groups does the compound have?

if slow evaporation fails, you can try other methods like diffusing other solvents, layering method, vapor diffusion etc

Dear Milan,

The hydrolysis of boronic esters to the boronic acid and the corresponding alcohol can take place by thionyl chloride and pyridine. Aryl boronic acids or esters can be hydrolyzed to the corresponding phenols by treating with hydroxylamine at RT.

New asymmetric syntheses with boronic esters and fluoroboranes Donald S. Matteson Pure Appl. Chem., Vol. 75, No. 9, pp. 1249–1253, 2003.

A mild conversion of arylboronic acids and their pinacolyl boronate esters into phenols using hydroxylamine Ebrahim Kianmehr , Tetrahedron Letters ,vol. 48 , Issue 15 , 9 April 2007.

Hoping this will be helpful,

Rafik

Hello Enrique,

Thanks a lot for your reply! Actually, I have tried to perform optimization with both M06-HF and the pure functional M06-L. However, the obtained result is invariant. Therefore, the error must be due to another factor

Dear,

The conditions mentioned by you clearly indicates that you are bound to get carboxylic acid as a product.

I am a little amazed that you got aldehyde in some cases. 

Anyway, the problem is due to moisture, you have H₂O so clearly it is bound to give carboxylic acid product.

If your goal is to get the aldehyde product I suggest you use Tetrapropylammonium perruthenate,  N-methylmorpholine N-oxide & molecular sieves.

Molecular sieves should be activated as they will absorb the moisture in it. 

I have personally performed this oxidation, so I told you about my experience. 

A link has been attached for you and it is called ley griffith oxidation

 Important to choose the right range of wavelength for  calculation.

Don"t you satisfied by results? It is  good.

Hi, I think Pedro got the right answer and you have paramagnetic species in your sample. The other option would be convection in the sample that can also affect topshim. Try "topshim convcomp". This compensates for convection. If this still does not help it is most likely the paramagnetism.

Mr. Bhattacharjee,

Using the same approach, i.e. TDDFT. Please pay attention to an example of H2O:

td=(triplets,root=1):

...............................

Excited State 1: Triplet-B1 7.5495 eV 164.23 nm f=0.0000 <S**2>=2.000

5 -> 6 0.70651

This state for optimization and/or second-order correction.

Total Energy, E(TD-HF/TD-KS) = -76.1085551488

Copying the excited state density for this state as the 1-particle RhoCI density.

Excited State 2: Triplet-A1 9.0043 eV 137.69 nm f=0.0000 <S**2>=2.000

4 -> 6 0.70397

Excited State 3: Triplet-A2 9.7743 eV 126.85 nm f=0.0000 <S**2>=2.000

5 -> 7 0.70596

SavETr: write IOETrn= 770 NScale= 10 NData= 16 NLR=1 LETran= 62.

................................

May be the attached article can help you

Best regards,

Pedro

Yes, you would have to take it into account!

I usually go by the inverse susceptibility. It should be proportional to the temperature (which is easily checked) and you can get the (squared) effective moment from the slope. In such a plot the paramagnetic Curie-Weiss temperature corresponds just to a horizontal displacement of the curve and not a fit parameter since that does not affect the slope. Nevertheless you can read it off directly from the intersect of the straight with the temperature axis!.

As has been already referred  that Imine bond in schiff bases is prone to hydrolysis. The rate of hydrolysis gets speeded up in presence of acid or base. The stationary phase used in column like silica or alumina have acidic sites which prompt the acid hydrolysis of the imine leading to the loss of product imine (in general case) so column chromatography is not sometimes  a good choice in case of schiff bases or imines.

This may or may not be true in your case as i donot know the exact nature of your compounds. I can recommend  purification through  solvent washing's. That is say for a hypothetical case we have an unreacted aldehyde   or  unreacted amine or ligand along with the product complex. Choose a dried solvent in which the product  is most soluble than the reactant aldehyde and ammine do multiple washings with solvent/ solvent system( work out such system over TLC for your case)  and remove the solvent to get the pure imine product.

in another case use multiple solvents first the one  in which aldeyde or amine of ligand is soluble to remove one of the reactants selectively then use another dried solvent to remove the second reactant selectively to purify  the final product.

Selective Distillation separation can also be used if the boiling points of the components of mixture are different.

If the product imine is totally insoluble in some solvent, then best method would be purification by product crystallization.

i have tried to give  general approaches, hope any of these works for your system

good luck.

thank you sir, could you plaese tell me more detailed 

A few things to note: firstly, HCl is not soluble in toluene, and therefore to say "the HCl content remains as 3-4%" does not sound correct.  In fact, toluene is used as a solvent precisely for this reason (as opposed to THF / Et2O /dioxane, which dissolve HCl; commercial solutions of HCl in these solvents are available ).

2. How do you know you see "3-4% HCl?" NMR? Give some info here.

3. You are working with pyridines; it is very likely whatever you see as "HCl" is the pyridinium salt. Heating and vac distillation probably won't help your cause. You will need to use an external base to deprotonate.

OK, thank you very much for your answer :)

May be this publication helps you

Organometallics 2008, 27, 175–180

thankyou for your answer

Mr. Swain,

For obtaining of Te-glasses you can read the following paper given as ref. 1. The procedure, however is different.

1. T. Kolev, B.Koleva, B. Schivachev, Oriented solids as a colloid suspension in nematic liquid

crystal – New tool for IR-spectroscopic and structural elucidation

of inorganic compounds and glasses, Inorganica Chimica Acta 361 (2008) 2002–2012

Dear Ramasamy Raj Kumar

Kindly find this paper of your interest....

Journal of Coordination Chemistry, 2015

Regards

thanks for  your answers!

More specifically, when there is one or more singly-occupied molecular orbital (SOMO), then the label SOMO is preferred instead of HOMO, since HOMO usually implies the highest doubly-occupied molecular orbital - likewise, LUMO is the lowest completely-unoccupied molecular orbital, so not the SOMO, but the next one

PS - Some of these processes are discussed in: http://www.sciencedirect.com/science/article/pii/S0045653513006942

From data I looked up, there is NO SBU which has the requisite bidentate mode of chelation with 3,5-PDC. You only have the monodentate version. So maybe you have to rethink this. Unless you can find an SBU with the bidentate mode of chelation, this is going to be a tough ask, unless you alter your reaction conditions totally like Dr. Paech has suggested. Good luck on the hunt.

Dear Rajamouli Boddula,

The following link contains a publication which depicts the units of the parameters in  Judd-Ofelt equations (theory):

Hoping this will be helpful,

rafik

Dear Sudarsan/

C-N activation or amide C-N bond cleavage?

Plasma cleaning will help for a typical carbon coating.  You may have to mill the carbon away with a FIB, but good luck, as Carbon is quite resilient to the FIB beam.  Curious to know results!

Not exactly. one reason of poor adhesion can be the oxide layer formation on the platinum surface.

Dear Saba,

I'm not sure what you want, but everything I have is in the .cell file in my earlier post. The file is plain text, so you can just read the lattice vectors (in Cartesians) and fractional positions straight from it (they're the first 2 blocks after the header).

If you want to visualise the structure, you can import the .cell file into jmol directly; in case you haven't come across it before, jmol is a free 3D visualiser, which can be downloaded from http://www.jmol.org.

All the best,

Phil