Two new Müller-type clusters, a one-dimensional solid [Cu(en)]₂₄[Cl ⊂V₁₅O₃₆]−12H₂O1, and a three-dimensional solid [Cu(pn)]₂₄[Cl ⊂V₁₈O₄₂]·12H₂O2, have been synthesised by employing identical hydrothermal conditions e_xcept varying the nature of organic diamine.1 crystallised in a chiral space groupP2₁2₁2₁ witha = 12.757(1),b = 18.927(2) andc = 28.590(3) Å, andZ =4.2 crystallised in a tetragonal system with space groupP4/nnc,a = 15.113(1) andc = 18.542(3) Å, andZ = 2. Mixed-valent vanadium ions in structures1 and2 have been established both by magnetisation and bond-length bond-valence measurements. Chemistry of formation of high nuclearity polyoxovanadate clusters is discussed.

Molecular recognition and aggregation occurring in solution are critical events towards the nucleation and growth of a crystal. However, controlling aggregation towards a particular supramolecular assembly is difficult due to lack of information on its thermodynamics and kinetics. Hence, the occurrence of supramolecularisomers is hardly recognized. In this paper, therefore, we demonstrate a retrosynthetic analysis to interpret the occurrence of isostructures and supramolecular isomers and predict the possibility of new phases in copperhalide-pyridazine- H₂O system. A significant feature of this paper is the use of crystal engineering tools, namely, synthons and tectons to interpret the phase diagram of a system. The structure-synthesis correlation discussed here provides chemical insight to evolve a synthetic protocol to interpret and predict the possibilityof supramolecular isomers in metal organic solids.

Two new Strandberg-type cluster-based phosphomolybdates {H-2a3mp}5[{PO3(OH)}{PO4}-Mo5O15], 1 and {H-2a4mp}₅[{PO₃(OH)}{PO₄}Mo₅O₁₅].6H₂O, 2 have been crystallized via solvent evaporationtechnique using 2-amino-3-methylpyridine (2a3mp) and 2-amino-4-methylpyridine (2a4mp) respectively. The solids were characterized using single-crystal X-ray diffraction, powder X-ray diffraction,fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and cyclic voltammetry. The solid 1 crystallized in monoclinic system with space group P2₁/c, a = 8.394(1),b = 27.398(6), c = 21.521(4) A ^° , b = 97.68(3)^°, Z = 4. The solid 2 crystallized in triclinic system with space group P-1, a = 11.728(1), b = 14.234(1), c = 19.589(1) A ^° , a = 68.906(3), b = 89.454(3), c = 66.559(3)^°,Z = 2. The solids 1 and 2 formed a supramolecular framework stabilized by hydrogen bonding interaction between cluster anions and organic moieties. CH…p interactions between the organic moieties reinforced thecrystal packing in 1 and 2. While crystal packing effects resulted in the formation of solvent-accessible voids in 1; aggregation of lattice water molecules in 2 facilitated the formation of pentameric water cluster. In addition, electrochemical behavior of 1 and 2 has also been investigated