To confirm the validity of our findings, we repeated the synthesis of SIPPs using the fatty amine, TDA, in a ABT-263 order 30-min reflux reaction. We fully characterized both structural and magnetic properties of the second batch of TDA-SIPPs and compared the results to those of the initial batch. Table 3 shows the comparison of the two different preparations of TDA-SIPPs. Reproducibility is seen in the size JPH203 and shape of the TDA-SIPPs. Likewise, fairly good reproducibility is also seen for the other structural characteristics such as volume, surface area, concentration, and iron/platinum stoichiometry. Table 4 compares the magnetic characterizations of the
two separate TDA-SIPP preparations. Again, the reproducibility is fairly good, and the particles had similar blocking temperatures and mass magnetizations. The average mass magnetization of the TDA-SIPPs was 108.98 A m2/kg iron ± 20.38 A m2/kg iron. This value of mass magnetization was still higher than that measured
for the other SIPPs made with all of the other fatty amines examined in this study (DDA, HDA, and ODA). Table 3 Comparison of SIPPs made with tetradecylamine and a 30-min reflux Value Description Units TDA-SIPP no. 1 TDA-SIPP no. 2 d Diameter nm 7.34 ± 1.22 7.86 ± 0.76 CV Coefficient of variation % 16.6 9.6 V p Particle volume cm3 2.07 × 10−19 2.55 × 10−19 S Surface area cm2 1.69 × 10−12 1.94 × 10−12 C p Suspension concentration mg/mL 4.29 ± 0.47 5.97 ± 0.14
C Fe Iron concentration mg/mL 0.214 ± 0.00007 0.729 ± 0.004 BIRB 796 molecular weight C Pt Platinum concentration mg/mL 0.583 ± 0.0003 2.503 ± 0.005 N a Fe Iron atoms in 1.0 mL – 2.31 × 1018 7.87 × 1018 N SIPP Nanoparticles per mL SIPP/mL 5.90 × 1014 1.83 × 1015 A Fe Atomic percent Fe at.% 56.2 50.4 A Pt Atomic percent Pt at.% 43.8 49.6 Fe/Pt Fe/Pt stoichiometry – 1.28 unless 1.02 M P FePt Mass per particle g 2.9 × 10−18 3.56 × 10−18 N a FePt Total Fe + Pt atoms per particle – 6,964 8,551 N P Fe Iron atoms per particle – 3913.8 4309.9 N P Pt Platinum atoms per particle – 3050.3 4241.5 Table 4 Average magnetic properties of TDA-SIPPs ( n = 2) Value Description Units TDA-SIPP no. 1 TDA-SIPP no. 2 Mean T b Blocking temperature K 100 150 125 ± 35.3 M sat Saturation magnetization A m2/kg iron 123.39 94.57 108.98 ± 20.38 K Effective anisotropy J/m3 1.7 × 105 2.0 × 105 1.8 × 105 ± 2.6 × 104 Conclusions Iron-platinum particles were successfully synthesized using four different fatty amines, from 12 to 18 carbons in length. Although some iron oxide contamination was seen, this decreased with increasing reflux time and decreasing chain length. Additionally, increasing the amount of time that the particles were allowed to reflux also increased the diameter of the particles, but decreased the iron concentration.