Evaporate the DMSO under vacuum. Reducing the pressure reduces the boiling point of the DMSO. At 2mbar pressure the boiling point of DMSO is +40°C and at 1mbar pressure the boiling point is +28°C, so find a friend with a good vacuum system.
To be sure that you keep your friendship with the owner of the vacuum system, take care, as DMSO in the wrong places can cause corrosion to metals (the sulphur is acidic) and damage plastics and elastomers.
As mentioned previously by vacuum it will be evaporate it quickly but if you leave a long time (about one month) maybe you will get a crystal so; you can analyze it by x-ray single crystal
Dear Bibekananda Gogoi, it certainly depends on the solubility of your metal complex. If you have a concentrated solution in DMSO, chances are that you can precipitate your metal complex from the solution by adding an excess of diethyl ether. Quite often, metal complexes are more or less insoluble in diethyl ether. If this precipitation method works, you could avoid the tedious evaporation of high-boiling DMSO. Good luck!
in my work, I used vacuum distillation but in some cases, I used to water this idea depends on the solubility and the nature of your compound if the compound will be precipitated by the addition of water or not.