Ferromagnetic [n-BuNH3](12)[(CuCl)(6)(SbW9O33)(2)]center dot 6H(2)O (1) and antiferromagnetic [n-BuNH3](12)[(MnCl)(6)center dot(AsW9O33)(2)]center dot 6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH3](12)[(CuCl)(6)(AsW9O33)(2)]center dot 6H(2)O (2) and [n-BuNH3](12)[(MnCl)(6)(SbW9O33)(2)]center dot 6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006.(1) When variable temperature (T) direct current (dc) magnetic susceptibility (chi(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, chi T-M vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.5 and -0.09 cm(-1) and g = 2.3 and 1.9, respectively. These J values were significantly distinguished from +61.0 and +0.14 cm(-1) for 2 and 3, respectively. The magnetization under the pulsed field (up to 10(3) T/s) at 0.5 K exhibits hysteresis loops in the adiabatic process, and the differential magnetization (dM/dB) plots against the pulsed field display peaks characteristic of resonant quantum tunneling of magnetization (QTM) at Zeeman crossed fields, indicating single-molecule magnets for 1-3. High-frequency ESR (HFESR) spectroscopy on polycrystalline samples provides g(parallel to) = 2.30, g(perpendicular to) = 2.19, and D = -0.147 cm(-1) for 1 (S = 3 ground state), g(parallel to) = 2.29, g(perpendicular to) = 2.20, and D = -0.145 cm(-1) for 2 (S = 3), and g(parallel to) = 2.03 and D = -0.007 cm(-1) for 3 (S = 15). An attempt to rationalize the magnetostructural correlation among 1-4, the structurally and magnetically modified D-3d-symmetric M (=Cu-II and Mn-II)(6) hexagons sandwiched by two diamagnetic alpha-B-[XW9O33](9-) (X = Sb-III and As-III) ligands through M-(mu(3)-O)-W linkages, is made. The strongest ferromagnetic coupling for the Cu-6 hexagon of 2, the structure of which approximately provides the Cu-6(mu(3)-O)(12) cylindrical geometry, is demonstrated by the polarization mechanism based on the point-dipole approximation, which provides a decrease of the ferromagnetic interaction due to the out-of-cylinder deviation of the Cu atoms for 1. The different nature of the magnetic exchange interaction in 3 and 4 is understood by the combined effect of the out-of plane deviation (the largest for 4) of the Mn atoms from the Mn(mu(3)-O)(2)Mn least-squares plane and the antiferromagnetic contribution arising from the large Mn-O-Mn bond angle. The primary contribution to D is discussed in terms of the magnetic-dipole dipole interaction between the electrons located on the magnetic sites in the M-6 hexagon.