Ten solid complexes of zinc nitrate w ith L-α-leucine(Leu),L-α-valine(Val),L-α-tryptophan(Try)and L-α-threonine(Thr )were prepared in water.The compositions of these complexes are determin ed by chemical analysis and elemental analysis,which are identified as Zn(Leu)(NO 3 ) 2 ·2H 2 O(A),Zn(Leu) 2 (NO 3 ) 2 ·H 2 O(B),Zn(Val)(NO 3 ) 2 ·2H 2 O(C),Zn(Val) 2 (NO 3 ) 2 ·H 2 O(D),Zn(Val) 3 (NO 3 ) 2 ·H 2 O(E),Zn(Try)(NO 3 ) 2 ·2H 2 O(F),Zn(Try) 2 (NO 3 ) 2 ·H 2 O(G),Zn(Thr )(NO 3 ) 2 ·2H 2 O(H),Zn(Thr ) 2 (NO 3 ) 2 ·H 2 O(I)and Zn(Thr ) 3 (NO 3 )·H 2 O(J).The constant-volume combustion en ergies of the complexes,Δ c U(complex),were determined by a precise rotating bomb calorimeter a t 298.15K.Standard enthalpies of combustion,Δ c H m (complex,s,298.15K),and standard enthalpies of formatio n,Δ f H m (complex,s,298.15K)for these complexes were calculated as(4523.22±2.08),(7208.86±4.28),(3442.21±1.85),(5971.21±3.32),(9007.26±4.24),(5802.35±2.14),(10891.58±3.01),(2147.40±1.28),(4120.83±0.99),(6444.68±3.85)kJ·mol -1 and(615.67±2.27),(1863.16±4.60),(1017.34±2.00),(1742.93±3.61),(2245.70±4.73),(1161.18±2.61),(1829.71±4.20),(1632.82±1.43),(1885.55±1.50),(2770.25±4.21)kJ·mol -1 ,respectively.
