• Joan Ribas

      Articles written in Journal of Chemical Sciences

    • Synthesis, molecular and crystalline architectures, and properties of a mononuclear complex [CoII (benzidine)2(NCS)2(OH2)2]

      Subhasish Kundu Subhasis Roy Kishalay Bhar Rajarshi Ghosh Chia-Her Lin Joan Ribas Barindra Kumar Ghosh

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      One mononuclear cobalt(II) compound of the type [Co(bnzd)2(NCS)2(OH2)2] (1) (bnzd = benzidine) has been isolated through a single-pot reaction of the molecular building components in MeOH-H2O solvent mixture at room temperature and characterized by physico-chemical and spectroscopic methods. The crystal structure of complex 1 has an octahedral geometry with trans, trans, trans orientations in the order (N$^a$,N$^a$), (N$^t$,N$^t$), (O$^w$,O$^w$) [N$^a$ = N(amine), N$^t$ = N(thiocyanate) and O$^w$ = O(water)]. In crystalline state, individual units of 1 are associated by weak cooperative O-H…N, O-H…S and N-H…S hydrogen bonds resulting in a 3D network structure. The compound is redox active and shows luminescence in MeOH solution. Thermal decomposition pattern of 1 reveals the presence of two coordinated water molecules. Variabletemperature magnetic susceptibility measurement shows significant orbital contribution and numerical matrix diagonalization method gives the best fit parameters: 𝛼 = Ak = 1.43; 𝜆 = −130 cm-1; 𝛥 = −864 cm-1; TIP = 0.000975; R = $1.19 \times 10^{−4}$.

    • An anti-ferromagnetic terephthalate-bridged trigonal prismatic dinuclear manganese(II) complex: Synthon of rare anion$^{\ldots} \pi$ interaction promoting dimensionality

      Somnath Choubey Soumi Chattopadhayay Kishalay Bhar Subhasis Roy Sumitava Khan Joan Ribas Barindra Kumar Ghosh

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      A dinuclear compound [Mn2(L)2(𝜇-tp)](PF6)2·3.57H2O (1) [L = N,N′-(bis(pyridin-2-yl)benzylidene)-1,3-propanediamine and tp = terephthalate dianion] has been isolated and characterized on the basis of microanalytical, spectroscopic and other physicochemical properties. X-ray structural study showed interesting bis(bidentate) bridging motif of tp in the dicationic dinuclear unit [Mn2(𝜇-tp)]2+. Each manganese(II) centre adopts a rare distorted trigonal prismatic geometry with an MnN4O2 chromophore.Chelation of the tetradentate Schiff base (L) along with bis(bidentate) bridging of two O atoms of tp complete hexacoordination around each manganese(II) centre. The dinuclear units of 1 are associated through cooperative C-H$\cdots$F hydrogen bonds and $\pi^{\cdot} \pi$, C-H$^{\cdots} \pi$ and rare anion$^{\cdots} \pi$ interactions to promote the dimensionality in a graded manner. Variable temperature magnetic susceptibility measurement of 1 in the 2-300 K temperature range revealed weak antiferromagnetic interaction presumably due to long bridging arm of tp.

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