Controlling the structure of manganese(II) phosphates by the choice and ratio of organophosphate and auxiliary ligands.
Tetranuclear manganese(II) phosphates [Mn(dipp)(bpy)](4)4 H(2)O (1) and [Mn(4)(dmpp)(2)(dmppH)(4)(bpy)(4)(H(2)O)(2)]H(2)O (2) have been prepared from Mn(OAc)(2)4 H(2)O and 2,6-diisopropylphenyl phosphate (dippH(2)) or 2,6-dimethylphenyl phosphate (dmppH(2)) in the presence of 2,2'-bipyridine (bpy). In contrast, the reaction between [Mn(bpy)(2)(OAc)(ClO(4))]H(2)O and dippH(2) affords [Mn(bpy)(2)(dippH)](2)2 ClO(4)2 CH(3)OH (3). The reactions of Mn(OAc)(2)4 H(2)O, dippH(2), and pyridine (py) or 3,5-dimethylpyrazole (dmpz) in CH(3)CN under reflux afford hexanuclear complexes [Mn(6)(dipp)(6)(py)(8)]2CH(3)CN (4) and [Mn(6)(dipp)(6)(dmpz)(6)(AcOH)(2)]2 H(2)O (5), respectively. Although compounds 1 and 2 are tetrameric, the former is a closed cubane-like structure resembling the D4R secondary building unit of zeolites, whereas the latter exists in a staircase structure with fused Mn(2)O(4)P(2) rings. The core structure of 3 contains a Mn(2)O(4)P(2) eight-membered ring that resembles the S4R building block of zeolites. Single-crystal X-ray diffraction studies reveal that compounds 4 and 5 have a similar core structure and differ from each other by the neutral ligands coordinated to manganese ions. All six phosphate ligands exist in a doubly deprotonated [(RO)PO(3) (2-)] form and exhibit two types of binding modes [5.222] and [3.111]. An interesting feature of compounds 1-5 is that although they are oligonuclear complexes, there is an absence of oxido bridges. The magnetic properties of compounds 1-5 have been investigated in the temperature range 5-298 K, and it was found that all the compounds obey the Curie law.
Murugavel
Ramaswamy
R
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India. rmv@chem.iitb.ac.in
Kuppuswamy
Subramaniam
S
Gogoi
Nayanmoni
N
Steiner
Alexander
A
Bacsa
John
J
Boomishankar
Ramamoorthy
R
Suresh
K G
KG
D018360:Crystallography, X-Ray; D008024:Ligands; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008968:Molecular Conformation; D010755:Organophosphates / Q000737:chemistry*; D010710:Phosphates / Q000138:chemical synthesis / Q000737:chemistry*
D008024:Ligands; D010755:Organophosphates; D010710:Phosphates; D008345:Manganese