Self-assembled Transition Metal Coordination Frameworks of ...

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Chapter 6
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Fig. 6.1. The MALDI MS spectrum of complex 24. The insets are calculated
isotropic distribution patterns.
The complex 25 exhibits peaks centered at m/z 2498.9, 1999, 1760, 1499,
1357.9, 1260, 1096.9, 1001.1, 857.9, 762, etc. The base peak at 1999 assigned as
[Zn4(HL2)L23]+ (calc. 1999) is characteristic. Interestingly, the molecular ion peak
with well resolved isotropic pattern at 2498.9 attributed to the species
[Zn4(HL2)4(BF4)4- 3CH3OH- 3H2O+H+]+ (calc. 2500) is found very rare for molecular
square complexes. Both these isotropic distribution patterns and their simulation
patterns are given in Fig. 6.2. The spectrum with other calculated distribution pattems
of peaks are given in Fig. 6.3. Presence of methanol may be attributed to the usage of
methanol dichloromethane mixture for MALDI measurement for complex 25. Other
species, found to be in well agreement with calculated isotropic distribution pattems,
include [Zn4L23-H++benzoylpyridine ketone hydrazone]+ (calc. 1760), [Zn3(HL2)L22]+
(calc. 1499), [Zn3(HL2)2(BF4)3- CH3OH]+ (calc. 1359), [Zn3L22-H++benzoylpyridine
ketone hydrazone]+ (calc. 1260) and [Zn2(HL2)L2]+ (calc. 1001).
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