EXPERIMENTAL INORGANIC CHEMISTRY
YELLOW NI(SALEN) BRICK RED NI(OAC)2*4H2O VO(SALEN) FOREST GREEN VO(SO4) [CR(SALEN)(NH3)2]CL* H2O DEEP OLIVE GREEN CRCL3*6H2O DARK BROWN MNCL2*4H2O BRIGHT RED FESO4*NH2O [FE(SALEN)(NH3)2]CL CHOCOLATE BROWN FECL3*6H2O DARK OLIVE GREEN CUSO4*5H2O A ISOLATED FROM THE SAME SYNTHESIS NI(SALEN) VO(SALEN) AROMATIC ?C-H ALIPHATIC ?C-H IMINE ?C=N AROMATIC ?C=C ALIPHATIC ?C-H ?C-N PHENOLIC ?C-O 1,2-DISUBSTITUTED AROMATIC ?C-H CH2- SINGLET -CH2 PH-H TRIPLET META TO -OH PH-H DOUBLET ORTHO TO -OH PH-H TRIPLET PARA TO -OH PH-H DOUBLET ORTHO TO IMINE IMINE H SINGLET OH BROAD SINGLET IMINE PH-H TRIPLET META TO - OH PH-H DOUBLET ORTHO TO - OH M ?MAX (NM) ? (M-1CM-1) ?MAX (NM) ? (M-1CM-1) ?MAX (NM) ? (M-1CM-1) SHOULDER EXPERIMENTAL INORGANIC CHEMISTRY TABLE 7 MAGNETIC MOMENTS AND METAL CATION CONFIGURATIONS OF M-SALEN COMPLEXES PRODUCT ?EFF (B M A) METAL CATION CONFIG , SPIN TYPE NI(SALEN) FE3+ D5, LOW [CO(SALEN)(NH3)2]CL*H2O A UNIT ABBREVIATION FOR BOHR MAGNETONS DISCUSSION SYNTHESIS OF SALENH2 IS STRAIGHTFORWARD AND VERY EASY TO ACCOMPLISH RECRYSTALLIZATION OF CRUDE SALENH2 IS RECOMMENDED FOR LIGAND PURITY SALICYLALDEHYDE AND ETHYLENEDIAMINE ARE PRONE TO DEGRADATION IN STORAGE AND WERE NOT PURIFIED BEFORE USE THE GOAL WAS TO DEVELOP A SIMPLE, “UNIVERSAL” SYNTHESIS IN USER-FRIENDLY SOLVENTS FOR MAKING M-SALEN COMPLEXES ONE CHALLENGE IS THAT COMMON METAL SALT REACTANTS ARE SOLUBLE IN WATER, AND SALENH2 IS SOLUBLE IN NON-POLAR SOLVENTS AN IMMISCIBLE MIXED-SOLVENT SYNTHESIS (TOLUENE/WATER) DID NOT WORK WELL IN PREPARATION OF NI(SALEN), SO THE SEARCH WAS ON TO DEVELOP A BETTER SOLVENT SYSTEM FOR A RELIABLE SYNTHESIS IN REVIEWING THE LITERATURE, THERE WERE MANY COMPLEX SYNTHESES USING EITHER MORE EXPENSIVE METAL COMPLEXES, OR UNDESIRABLE SOLVENTS, SUCH AS TOLUENE AND ACETONE ONE COMMON THEME WAS THE USE OF ETHANOL SOLVENT – MISCIBLE WITH WATER, AS DESIRED SALENH2 BECOMES MORE SOLUBLE IN ETHANOL WITH INCREASE IN TEMPERATURE METHANOL WORKED JUST AS WELL IN REPEAT SYNTHESES ANOTHER ISSUE TO BE RESOLVED WAS ADDITION OF BASE TO DEPROTONATE THE LIGAND, ENABLING FORMATION OF THE M-SALEN COMPLEX CONCENTRATED AMMONIA WORKED BEST SINCE IT FORMED ALCOHOL-SOLUBLE SIDE PRODUCTS AND ADDED JUST A BIT OF WATER TO THE REACTION, WHICH INCREASED SOLUBILITY OF THE STARTING METAL SALT, BUT DID NOT CAUSE THE LIGAND TO PRECIPITATE IN ALL CASES, SOME TO MOST OF THE M-SALEN PRODUCT PRECIPITATED FROM THE REACTION AS IT FORMED WHERE THE INDIVIDUAL SYNTHESES DIFFER IS IN THE ISOLATION AND PURIFICATION OF THE PRODUCT, PROVIDING STUDENTS WITH THE OPPORTUNITY TO FIGURE THIS OUT ON THEIR OWN BY TRIAL AND ERROR, JUST LIKE IN RESEARCH (15) THE VALUE OF THIS EXERCISE IS THAT IT ALLOWS SOPHOMORE-JUNIOR UNDERGRADUATES TO EXPLORE A SYNTHETIC LANDSCAPE THAT IS WELL KNOWN TO THE PROFESSOR, WHO CAN GUIDE THE STUDENTS APPROPRIATELY IT’S LIKE AN INITIAL STEP INTO THE WORLD OF EXPERIMENTAL SYNTHETIC CHEMISTRY RESEARCH