Isolation of a Zinc Phosphate Primary Building Unit, [C6N2H18]2+[Zn(HPO4)(H2PO4)2]2−, and Its Transformation to an Open-Framework Phosphate, [C6N2H18]2+[Zn3(H2O)4(HPO4)4]2−

✍ Scribed by S. Neeraj; Srinivasan Natarajan; C.N.R. Rao

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 165 KB
• Volume: 150
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8628

✦ Synopsis

A 4-membered ring zinc phosphate monomer, I, [C 6 N 2 H 18 ] 2؉ [Zn(HPO 4 )(H 2 PO 4 ) 2 ] 2؊ , has been isolated by the reaction of the Zn 2؉ with the amine, N,N,N,N-tetramethylethylenediamine (TMED) and H 3 PO 4 at room temperature over an extended period of time. It could also be prepared by the reaction of the amine phosphate, [C 6 N 2 H 18 ][HPO 4 ] 2H 2 O, with Zn 2؉ in the temperature range 30+803C. The phosphate monomer consists of a network of ZnO 4 , PO 2 (OH) 2 , and PO 3 (OH) tetrahedral units linked by their vertices, forming isolated 4-membered rings that are held by hydrogen bond interactions. Interestingly, I, on mild heating, transform into a layered structure, II, [C 6 N 2 H 18 ] 2؉ [Zn 3 (H 2 O) 4 (HPO 4 ) 4 ] 2؊ . The structure of II consists of a network of ZnO 4 , ZnO 2 (H 2 O) 4 , and PO 3 (OH) moieties sharing the vertices, forming a layered architecture. The formation of a layered structure from the 4-membered ring monomer suggests that the 4-membered ring is likely to be the primary building unit of the open-framework phosphates.