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Assembly of orotic acid (H3Or, 1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidinecarboxylic) and Cd(NO3)·6H2O yielded a coordination polymer, [(Cd(Hor)·2.5H2O)2]n (1), which has been characterized by X-ray single-crystal diffraction, TGA, and fluorescence spectra. Single-crystal X-ray structural analyses reveal that 1 is a hydrogen-bonded binuclear Cd-orotate coordination polymer in which both Cd2+ ions have different coordination environments with identical distorted octahedral geometry. Crystal data for 1: monoclinic, space group P21/n, a = 7.0209(10) Å, b = 13.974(2) Å, c = 17.541(3) Å, β = 98.842(2)°, V = 1700.5(4) Å, Z = 4, R1 = 0.0269, wR2 = 0.0612, θmax = 25.960. The emission spectrum of the Cd-complex recorded with 265 nm excitation wavelength reveals the complex has strong blue luminescence with the peak maximum 420 nm (2.95 eV) as a result of the n–π* and π–π* transitions on the H3Or ligand. [ABSTRACT FROM AUTHOR]

Two new supramolecular synthon induced single crystals of metal-orotato complexes of formula [Cu(Orotate)·2H 2 O] 2 ( 1 ), [Mn(Orotate) 2 ·2H 2 O]·2H 2 O] ( 2 ), have been engineered and synthesized by self-assembly of metal salts with orotic acid in presence of 25% ammonia solution. Although both complexes crystallize in similar crystal system and different coordination geometries [(square planar ( 1 ), octahedral ( 2 )] but identical synthon patterns recur after complex formation. N H⋯O, O H⋯O synthons were the only artifact for both the hydrogen bonded metal–organic architecture. X-ray structural analysis, EPR, temperature independent paramagnetism (TIP) analysis, have been discussed. DFT calculation is used to rationalize the magnetic behavior of both the complexes. These calculations underline the pathway of magnetic exchange interactions through N H⋯O, O H⋯O supramolecular synthons and confirm, that the magnetic interactions propagate through such contacts in complex 1 and 2 . [ABSTRACT FROM AUTHOR]

Hydrothermal self-assembly of orotic acid (C 5 H 4 N 2 O 4 OrH 3 ) with metal salt Cu(Ac) 2 ·H 2 O yielded a new OrH based hydrogen bonded coordination network of formula [Cu(OrH)(2NH 3 )(H 2 O)]·H 2 O ( 1 ) and [Cu(OrH) (2NH 3 )] 2 ( 2 ). Single crystal X–ray study on 1 confirms that +2 charges on the metal ions (Cu 2+ ) are balanced by OrH anion. N–H⋯O and O–H⋯O hydrogen bonding synthons are the only artifact for the resulting hydrogen bonded copper-OrH architecture. Temperature dependent measurements of magnetic susceptibility reveals the occurrence of competitive exchange interactions with a net ferromagnetic character in 1 ( J  = +0.48 cm −1 ) and strong antiferromagnetic interaction in 2 ( J  = −4.93 cm −1 ). Magnetic superexchange interaction transmitted through equatorial–axial hydrogen bridge system promotes weak ferromagnetic interactions in 1 while in 2 it is in basal-basal position, in which two d x2-y2 orbitals is involved in exchange mechanism reveals the coexistence of two antiferromagnetic exchange pathways, intramolecular much stronger than intermolecular. The natural bond orbital (NBO) analysis applied separately to α and β spin density matrices clearly shows two important magnetic superexchange pathway with shorter Cu⋯Cu contact 5.542(4) Å and 4.845(4) Å or 5.755(1) Å in ( 1 ) and inter dimer 6.665(1) Å and 4.6744(9) Å for ( 2 ). [ABSTRACT FROM AUTHOR]

The synthesis and characterization of new supramolecular networks based on mixed ligands as orotate with 1,3-di(4-pyridyl)propane or malonic acid are reported. Both coordination polymers was characterized using X-ray crystallography, magnetic measurements, electron paramagnetic resonance, and density functional theory calculations. The significant role of hydrogen bonding O H⋯O and N H⋯O in formation of 2D coordination network and magnetic exchange pathway was found. [Display omitted] Two new coordination network based on mixed ligands, orotic acid potassium salt with 1,3-Di(4-pyridyl)propane (dpp) and malonic acid at room temperature were synthesized as [Cu 2 (dpp)(HOr) 2 ·2H 2 O]n (1) and [Cu(HOr)(H 2 O) 2 ]n (2) respectively. To strategically design and synthesize Cu(II)-coordination networks where N H⋯O and O H⋯O hydrogen bonds act as connecting tools in the construction of three dimensional networks have been discussed. The both complexes have been characterized by single crystal X-ray analysis, elemental analysis, magneto-structural study along with EPR study. The magnetic data reveals that the complex 1 shows antiferromagnetic exchange interactions while complex 2 shows ferromagnetic exchange interaction through {⋯H N C O} dimer. The DFT calculation and HOMO/LUMO molecular orbitals analysis is used to rationalized the magnetic behavior in these coordination polymers. [ABSTRACT FROM AUTHOR]