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摘要
The effect of de-tert-butylation on the coordinating properties of the 24-membered hexaazadithiophenolate macrocycle 13,27-bis(tert-butyl)-3,6,9,17,20,23-hexaazatricyclo[23.3.1.11.15]triaconta-1(28),11,13,15(30),25,26-hexaene-29,30-dithiol (H2L1) has been examined. For this purpose, a series of mixed-ligand NiII and ZnII complexes of the de-tert-butylated hexaaminedithiophenolate macrocycle H2L2were prepared and characterized, namely, [NiII2L2(Cl)]+(1b), [ZnII2L2(OAc)]+ (2b), [NiII2L2(O2CCH=CHPh)]+ (3b), [ZnII2L2(O2CCH=CHPh)]+ (4b), [NiII2L2(O2CC14H17)]+ (5b), [ZnII2L2(O2CC14H17)]+ (6b, in which C14H17CO2 =3,4-dimethyl-6-phenylcyclohex-3-enecarboxylate), [NiII2L2(O2CC6H4-3-OMe)]+ (7b), and [ZnII2L2(O2CC6H4-3-OMe)]+ (8b). The synthesis and characterization data for complexes [NiII2L4(O2CC6H4-3-OMe)]+ (7d) and [ZnII2L4(O2CC6H4-3-OMe)]+ (8d), in which H2L4 represents the S-oxygenated (bis-sulfonate) derivative of H2L2 are also reported. The de-tert-butylated macrocycles H2L2 (and H2L4) behave essentially in the same fashion as H2L1 (and H2L3) producing dinuclear mixed-ligand [M2L(mu-L%26apos;)]+ complexes with analogous bioctahedral core structures in similar good yields and reaction times. The spectroscopic features of the [M2L2(mu-L%26apos;)]+ and [M2L4(mu-L%26apos;)]+ complexes resemble those of theanalogous complexes supported by the tert-butylated derivatives H2L1 and H2L3. One major difference between the [M2L1,3(mu-L%26apos;)]+ and [M2L2,4(mu-L%26apos;)]+ complexes concerns the depth of the binding pocket of the compounds, which is significantly reduced upon removing the tert-butyl substituents. Another significant difference associated with removal of the tert-butyl substituent concerns the less pronounced differences of the relative stability constants for the carboxylato-bridged [M2L2(mu-O2CR)]+ complexes {as compared to the [M2L1(mu-O2CR)]+ complexes}. These stability differences can be qualitatively explained in terms of less pronounced intramolecular CH...p and/or van der Waals interactions in the de-tert-butylated complex systems.
- 出版日期2012-5
