Complexation properties of N-thiophosphorylated thiourea 2-PyNHC(S)NHP(S)(OiPr)2 towards Ni(II)

Supramolecular structures of NiII and CuII with the sterically demanding Schiff base dyes driven by cooperative action of preagostic and other non-covalent interactions

This work reports on synthesis and extensive experimental and theoretical investigations on photophysical, structural and thermal properties of the NiII and CuII discrete mononuclear homoleptic complexes [Ni(L I,II)2] and [Cu(L I,II)2] fabricated from the Schiff base dyes o-HOC6H4-CH=N-cyclo-C6H11 (HL I) and o-HOC10H6-CH=N-cyclo-C6H11 (HL II), containing the sterically crowding cyclo-hexyl units. The six-membered metallocycles adopt a clearly defined envelope conformation in [Ni(L II)2], while they are much more planar in the structures of [Ni(L I)2] and [Cu(L I,II)2]. It has been demonstrated by in-depth bonding analyses based on the ETS-NOCV and Interacting Quantum Atoms energy-decomposition schemes that application of the bulky substituents, containing several C-H groups, has led to the formation of a set of classical and unintuitive intra- and inter-molecular interactions. All together they are responsible for the high stability of [Ni(L I,II)2] and [Cu(L I,II)2]. More specifically, London dispersion dominated intramolecular C-H⋯O, C-H⋯N and C-H⋯H-C hydrogen bonds are recognized and, importantly, the attractive, chiefly the Coulomb driven, preagostic (not repulsive anagostic) C-H⋯Ni/Cu interactions have been discovered despite their relatively long distances (∼2.8-3.1 Å). All the complexes are further stabilized by the extremely efficient intermolecular C-H⋯π(benzene) and C-H⋯π(chelate) interactions, where both the charge-delocalization and London dispersion constituents appear to be crucial for the crystal packing of the obtained complexes. All the complexes were found to be photoluminescent in CH2Cl2, with [Cu(L II)2] exhibiting the most pronounced emission - the time-dependent density-functional-theory computations revealed that it is mostly caused by metal-to-ligand charge-transfer transitions.

The first coordination polymers with an [O]2[N]P(S)-Hg segment: a combined experimental, theoretical and database study

The study of one-dimensional coordination polymers {Hg₂Cl₄L₁}_n (1), {HgBr₂L₁}_n (2) and {Hg₂Cl₄L₂}_n (3) (L₁ = (S)P(OC₂H₅)₂NHC₆H₄NHP(S)(OC₂H₅)₂ and L₂ = (S)P(OC₂H₅)₂NC₄H₈NP(S)(OC₂H₅)₂) is the first such structural study of Hg(ii) coordination polymers with (O)₂(N)PS-based ligands. The mercury atoms adopt a distorted trigonal pyramidal environment, Hg(Cl)₃(S) for 1 and 3 and Hg(Br)₂(S)₂ for 2, and the difference observed in the stoichiometry of mercury halide to the thiophosphoramide ligand in 1 and 3 with respect to the one in 2 is a result of the formation of the Hg₂Cl₂ ring, however, the molar ratio 2 : 1 of HgX₂ (X = Cl and Br) to ligand was used for the preparation of all three complexes. The strengths of mercury-sulfur and mercury-halide covalent bonds are evaluated by theoretical calculations (QTAIM and NBO) which show their principally electrostatic nature with a partial covalent contribution. The energies of interactions building supramolecular assemblies and intramolecular interactions, i.e. NHCl, NHBr, CHCl, CHBr, CHO, CHS and CHπ, are theoretically evaluated. The characteristic structural features arising from the aromatic/aliphatic linkers in the ligands and chloride/bromide attached to mercury are investigated by Hirshfeld surface analysis and fingerprint plots.

An intermolecular pyrene excimer in the pyrene-labeled N-thiophosphorylated thiourea and its nickel(ii) complex

(1-pyrene)NHC(S)NHP(S)(OiPr)₂ (HL) and its Ni^II complex ([NiL2]) have been synthesized. Both HL and [NiL2] were found to be emissive in solution of CH₂Cl₂, which is due to the concentration dependent emission of the pyrene monomer and excimer.

N-Salicylidene aniline derivatives based on the N′-thiophosphorylated thiourea scaffold

A new family of thermochromic N′-thiophosphorylated thiourea-containing N-salicylidene aniline derivatives (anils) of the common formula 6-{(2-OH-aryl)–CHN}-Py-2-NHC(S)NHP(S)(OiPr)₂ has been synthesized by the condensation of N-thiophosphorylated thiourea 6-NH₂-Py-2-NHC(S)NHP(S)(OiPr)₂ with the corresponding salicylaldehyde.

From a mononuclear Ni(II) precursor to antiferromagnetically coupled trinuclear double-stranded helicates

Reaction of the mononuclear Ni(II) complex [Ni{2-Py(6-NH2)NHC(S)NP(S)(OiPr)2}2] with different salicylaldehydes leads to new antiferromagnetically coupled trinuclear double-stranded helicates , where Ni(II) metal ions are coordinated by two bis-anionic thiourea ligands and two deprotonated molecules of the corresponding aldehyde.