Exploring two helical centrosymmetric homotetranuclear Cu (II) bis (salamo)‐based complexes

Abstract

Two helical centrosymmetric homotetranuclear Cu (II) complexes, [Cu 4 (L) 2 (EtOH) 2 ](ClO 4 ) 2 Á2EtOHÁ2CHCl 3 (1) and [{Cu 4 (L) 2 (EtOH) 2 }{Cu 4 (L) 2 (HNO 3 ) 2 }] (NO 3 ) 4 Á3EtOHÁ3MeOH (2), were synthesized by the reactions of a symmetric bis (salamo)-based ligand H 3 L with Cu(ClO) 2 Á6H 2 O and Cu(NO) 3 Á3H 2 O, respectively, and certified by elemental analyses, UV-Visible absorption spectra, infrared spectra and single-crystal X-ray analysis techniques. X-ray crystal structure analyses reveal that four Cu (II) atoms of complex 1 are attached to two deprotonated ligand (L) 3À units with the help of two coordinated ethanol molecules, and then forming a helical centrosymmetric complex by H-bonding and πÁ Á Áπ interactions. While complex 2 unit cell contains two crystallographically independent but chemically identical homotetranuclear complexes (molecules A and B), eight Cu (II) atoms are coordinated by four deprotonated ligand (L) 3À units. The coordination mode of four Cu (II) atoms from molecule A is the same as complex 1; at the same time, oxygen atoms on nitrates are involved in the coordination of another four Cu (II) atoms from molecule B. The short-range interactions in complexes 1 and 2 were calculated by Hirshfeld surfaces analyses. The molecular orbital energy levels, molecular stabilities of complexes 1 and 2 were analyzed by DFT calculations. In addition, antibacterial assays were also investigated in detail.

Coordination-Driven Salamo-Salen-Salamo-Type Multinuclear Transition Metal(II) Complexes: Synthesis, Structure, Luminescence, Transformation of Configuration, and Nuclearity Induced by the Acetylacetone Anion

“…The hydrogen atom, H­(21C), attached to the carbon atom, C(21), is involved in intermolecular C–H···π interaction with the naphthalene ring, Cg(14) [C(41)–C(42)–C(43)–C(44)–C(45)–C(46)]. The naphthalene rings Cg(9) [C(1)–C(2)–C(3)–C(4)–C(9)–C(10)] and Cg(13) [C(37)–C(38)–C(39)–C(40)–C(41)–C(46)] are involved in intermolecular π···π interactions with Cg(12) [C(26)–C(27)–C(28)–C(29)–C(30)–C(31)] and Cg(11) [C(15)–C(16)–C(17)–C(18)–C(19)–C(20)], respectively. , …”

“…In addition, a significant intramolecular C− H•••π interaction and two pairs of intramolecular π•••π interactions were also observed in complex 2. 36 The hydrogen atom, H(21C), attached to the carbon atom, C( 21 37,38 To elucidate the counter-anion effect on structures, M(OAc) 2 •4H 2 O was used to replace M(O 2 C 5 H 7 ) 2 to perform the same experiment. Notably, it will prevent metal(II) ions from entering the salamo pocket under the influence of counteranions, acetylacetone anions.…”

Study for the hydrogen evolution reaction of doped carbon paste composite electrodes with multinuclear Ag(I) complexes based on nitrogen heterocyclic ligand

“…In addition, the UV/Vis spectra of the L and 1-2 in DMF solution show that the ligand has two maximum absorption peaks at λ max = 277, 283 nm, which is due to the π-π * and n-π * transitions inside the ligand. The maximum absorption peaks of 1-2 showed a slight shift, which further proved that the ligand may be involved in the coordination of Ag(I) [52][53][54][55][56].…”