It looks like you've made a completely different material. Take a look at:

http://link.springer.com/article/10.1007/s10934-014-9823-6

Thanks a lot for the article.

When comparing with the PXRD patterns reported about MOF-2, mine looks totally different. But when reading about MOF-5, I saw that a phase transition is possible for MOF-5 when its exposed to air for 24 hours. By anychance do you know whether there is a phase transition possible for for MOF-2 as well ? I couldn't find any information regarding the stability of MOF-2. 

I need to know about the stability of MOF-2, to see whether the difference in XRD is due to a phase transition or due to a error in the synthetic procedure. 

If you have single crystal for the MOF-2 (as you synthesized) go for the sinlge crystal data collection. If unit cell differs from that of the earlier reported, definitely it would be a new compound. You dont have to collect full data, just do unit cell determination and compare with the reported one

hope it would help

Zn-based dicarboxylate MOFs as MOF-5 and MOF-2 are strongly air sensitive. They starts to decompose in few minutes after exposure to the atmosphere because of metal-linker bond hydrolysis. So, it is quite likely that your MOF was damaged by contact with atmospheric water in the time between the synthesis and the starting of the XRD measurements.

MOF-2 slowly loses its structure during time, especially if it is just left on air. You should store it in some inert atmosphere to keep it as original. Apparently your MOF transformed to something else. For me it looks like a hydrated Zn(BDC)(H2O)2 phase (see Edgar et al. Chem Eur J 2001, 7, 5168 - Structure 7), which occurs from desolvated MOF2 upon hydration.

i agree that thier should be decomposition  due moisture ..this what im trying to solve by prepare MOF 177 and solve the effect of moisture 

any idea please 

Dear Abdel-Rahman.

Just keep it inert....all the time!

Unlike MOF-5, MOF-2 is moisture stable.  II am sure, I am working with Zn-based MOFs for about 3 years.. If you heat MOF-2 and remove the axial solvent molecules, it becomes moisture sensitive (as it is desriced in Chem Eur J 2001, 7, 5168 - Structure 7). But unless rremoving of axial solvents, it is water stable.  So, something went wrong on your synthesis.

The claim of MOF synthesis is very simple, because if you mixed organic cluster and inorganic ligand in a solvent and then heating and cooling process is done, you think that MOF was synthesized. This is the beginning of confusion and if your criteria for recognition is TGA, you're more astray. In fact, if you done common procedure for synthesis of MOF, apparently you think that your MOF was synthesized. Exactly like you.  In fact,you don't attention the residual weight percent at the end of the TGA analysis. your residual weight percent is about 32%, but in Ref, the residual weight percent is about 24%. This difference attributed to more zinc molecule that encapsulated in MOF-2 framework.

please see following articles;

http://link.springer.com/article/10.1007/s40195-013-0105-0

http://www.sciencedirect.com/science/article/pii/S1226086X14000173

http://link.springer.com/article/10.1007/s11814-014-0315-9

http://www.scielo.br/scielo.php?pid=S0104-66322016000100225&script=sci_abstract

http://www.sciencedirect.com/science/article/pii/S0921510711000316

in fact you don't synthesized a pure MOF-2. you need a perfect procedure for washing and drying of MOF-2 (according above articles).

It is so easy to make MOF-2. I give you my own (not published) recipe to grow huge MOF-2 single crystal MOFs. Just  dissolve 0.32 g terephtalic acid and 0.767 g Zn(NO3)2 * 6 H2O in 20 DMF. Prepare a solution of 115 mg TEA in 30 ml DMF. Carefully layer the TEA/DMF solution to the top of the Zn(NO)3-terephtalic acid solution. Avoid fast mixing the two solution, just let them to mix by slow diffusion Just let it for a week to grow, and you will have huge single crystals of MOF-2.

It is similar to O.M Yaghi's method (jacs.120.8571.1998). Yaghi's group diffused TEA vapours to Zn/terephtalic solution in DMF/toluene. It worked me fine in only DMF and just layering...

There are many other methods for producing MOF-2. For eg., the scaled up method of BASF (J. Mater. Chem., 16, 626-636), or a solvothermal reaction followed by boiling boiling the crystals in water (!): http://www.rsc.org/suppdata/cc/c1/c1cc12510a/c1cc12510a.pdf. Just if you see the last one (solvothermal reaction, than boiling in water) MOF-2 mustn't be water sensitive! I really dont know, why  did many people answer it is water sensitive...  I really dislike the idea of downvoting previous answers, but i really don't know why they told it is moisture sensitive...  Pentacoordinated Zn atoms are stable.

MOF-5 is so moisture sensitive, since it have tetracoordinated Zn atoms. You can store water sensitive samples, like MOF-5 in inert atmosphere, or unde hydrophopic solvents (for eg. chloroform or toluene).

I hope it helped

Is it a single crystal? Then go for Single crystal XRD. After that you will get clear picture.

Thanks a lot for the feedback. Unfortunately I dont have facilities to do a single XRD. I tryed a solvothermal synthesis published by "Links, D. A. ChemComm Top-down Fabrication of Crystalline Metal – Organic Framework Nanosheets W. 2011, 8436–8438." And thank you sir, David Foldes for the procedure. 

And sir, I think what you said is right about MOF-2 been moisture stable. Because yesterday I figured out that I have accidentally got MOF-2 while synthesizing MOF-5. and the PXRD taken a month after the synthesis of the MOF is attached below. and within the month the MOF was exposed to atmosphere. But no phase change can be observed from the PXRD.       

Did you use the solvothermal method, followed by water treatment for preparing MOF-2? Well, I never tryed this method, so I can not say anithing about it.

Believe me, MOF-2 is maybe the only Zn-carboxylate based MOF, that is not moisture sensitive..

Yes, it is a typical case, to get MOF-2 instead of MOF-5. If I would like to be correct, I must tell you, I never wanted to prepare MOF-2 :D.

I working with MOF-5 analogue compounds. The better procedure, to prepare MOF-5: Kaye et. al, jacs 129, 14176 (2007). The preparation method is described in the supporting information, I attach it. I used the method with (dryed) DMF, but without adding any water to it (in the original methos, you mix 49 ml DMF with  1 ml water). It works very well!

By the method of Kaye et al, you can prepare the best quality MOF-5 sample, with huge BET surface area.

Also you can measure PXRD for single crystals too, if you don't have ability of SXRD. A little bit grinding will help to fill them in to PXRD capillar (but don't grind too much, too much grinding can change structure).

the solvothermal method followed by water treatment didnt give the proper XRD (attached in the question) which made me think whether MOF-2 becomes unstable within the water treatment step. Got it sorted with all of your help. Thanks !

I dont think I can try MOF-5 for drug loading as i need to soak the MOF in a drug dissolved ethanol solution for about a day in order to load the drug. so MOF-5 is out of option for me. 

Does anyone know a Zinc + 1,3,5-benzenetricarboxylic acid stable, porous MOF ? Zn-HKUST-1 seems to be non porous. thus out of option. 

And thanks for giving me the idea of DSC (Differential scanning calorimetry) which would help me approach this question in the aspect of purity. 

Have a look through the CCDC:  http://webcsd.ccdc.cam.ac.uk/substructure_search.php

You will need Firefox. Some possibilities:

10.1016/j.micromeso.2005.11.049

10.1039/c2ce26290h

It is important that you sort through them, because only you know how large you need the pores to be to accomodate the drug molecule that you are using.

 Thanks Laura for guiding me. Many structures are reported for Zn + Trimesic acid combination without stability and available porosity information.

If im not mistaken In Zn-HKUST-1 it has been observed that even though the structure has 3D channels, the structure collapse upon activation. Therefore ultimately the structure remains non porous. Likewise, wont these structures collapse aswell?

Thanks again for the references. I will read more along this line.   

MOF-2 is sensitive to water in air

Have you compared the obtained XRD pattern with the pattern from PDF database (not simulated)?