Inverse bilayer structure of mononuclear Co^II and Ni^II complexes of the type M(H₂O)₃(SO₄)(4-CNpy)₂

Abstract

Two new metal compounds of the formula [M(H(2)O)(3)(SO(4))(4-CNpy)(2)] x H(2)O [M = Ni (1) and Co (2), 4-CNpy = 4-cyanopyridine] have been prepared and studied by X-ray diffraction. In both of these compounds the 4-CNpy ligands are coordinated via pyridyl-N atoms to the metal ions in a cis fashion. The neutral complexes along with the uncoordinated H(2)O molecules are glued together preferentially into inverse bilayers by non-covalent interactions, including unique interlayer pi-pi interactions between antiparallel nitrile groups. Hartree-Fock and density-functional theory (DFT) calculations indicate that the pi-pi interactions are energetically significant. The unit-cell similarity index (Pi) of 0.0046 for the compounds suggests their isostructurality, which is also supported by their X-ray powder diffraction patterns that can be almost superimposed.

Structural topologies involving energetically significant antiparallel π-stacking and unconventional N(nitrile)⋯π(fumarate) contacts in dinuclear Zn(ii) and polymeric Mn(ii) compounds: antiproliferative evaluation and theoretical studies

“…Furthermore, antiparallel nitrile-nitrile interactions are observed in the layered assembly of compound 2 having the centroidcentroid separation of 3.424(3) Å between the p systems of the two nitrile fragments from the adjacent chains. 55 The C23-C27RN28 and C13-C17RN18 angles of 3-CNpy in compound 2 are slightly deviated from linearity (178.771 and 179.041 respectively) which can be ascribed to the involvement of the nitrile moieties attached to the aromatic rings in non-covalent interactions. 56 The 1D polymeric chains of compound 2 are also involved in the formation of a layered assembly along the crystallographic bc plane aided by O-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonding interactions (Fig.…”

‘Charge Reverse’ Halogen Bonding Contacts in Metal-Organic Multi-Component Compounds: Antiproliferative Evaluation and Theoretical Studies

“…An analysis of the crystal structure of compound 1 unfolds the formation of 1D supramolecular chain along the crystallographic a axis, aided by anti-parallel CN•••CN π-stacked and C-H•••N hydrogen bonding interactions (Figure S1). The nitrile moieties of adjacent monomeric units are involved in anti-parallel CN•••CN π-stacking interactions with C15•••N8 and C7•••N16 separation distances of 3.61 and 3.57 Å, respectively [71]. The corresponding C13−C15≡N16 and C3−C7≡N8 angles of the coordinated 3-CNpy moieties in compound 1 deviate slightly from linearity (178.4 and 178.2 • ), which may be an outcome of the non-covalent interactions of the nitrile moieties attached to the aromatic rings [72].…”