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چکیده
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We present the synthesis and structural and computational characterization of a heteroleptic dinuclear discrete complex [Cd2(μ1,3-NCS)2(NCS)2(LI)2]·4MeOH (1·4MeOH), where LI is the product of hydrolysis of one of the 2-PyC(Ph) groups of the parent ligand 1,2-diphenyl-1,2-bis((phenyl(pyridin-2-yl)methylene)hydrazono)ethane (L), fabricated from a mixture of Cd(NO3)2·4H2O and NH4NCS in methanol. An analogous procedure but in EtOH and iPrOH yielded crystals of the heteroleptic dinuclear discrete complex [Cd2(μ1,3-NCS)2(NCS)2(L)2] (2) and the polymeric complex of the composition [Cd3(NCS)6(L)]n (3). The bulky helical ligand L in the constituting CdII based synthons has been found to exhibit a quasi-aromatic Möbius features as revealed by the electron density of delocalized bonds method as well as the extended transition state coupled with natural orbitals for chemical valence calculations. It means that a transition metal induces π-electron delocalization solely in the ligand’s part; however, the d orbitals of CdII do not overlap with the π-system of L. It is further found that the donor/acceptor character of the substituents attached to L can tune the Möbius quasi-aromaticity. Finally, formation of the crystals is driven not only by the typical ionic/dative Cd–N bonds, but also by a number of noncovalent interactions starting from classic hydrogen bonds (N–H···N, N–H···O) going through π···π, C–H···π, to end up with nonintuitive and recently topical Lp···Lp interactions (Lp – lone pair): e.g., C···C, N···N, N···S, S···S as well as London dispersion dominated homopolar dihydrogen interactions C–H···H–C.
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