On the synthesis and characterization of open- framework antimony(III) diphosphonates

摘要

Diphosphonates of antimony(III) were preparedby hydrothermal methods starting from Sb_2O_3 and thealkyldiphophonic acids, (H_2O_3P(CH_2)_nPO_3H_2), n=1,2 and 3, in the presence of HF. The methylenediphosphonicacid yields crystals of an oxydiphosphoate,Sb_2O(O_3PCH_2PO_3) (1): space group Pc, a=4.6935(7),b=7.2515(1), c=11.1025(2)?, #beta#=94.724(3)deg,R_1(F)=0.0397. compound 1 is based upon a three-dimensional network of #PSI#-trigonal bipyramidal (SbO_4)units and (nearly) tetrahedral ((CH_2)PO_3) units. The three-dimensional framework of 1 features nine-rings formed by fourSb and five P atoms, forming narrow channels running parallelto the a axis. The ethylenediphosphonic acid gives crystals ofSb(O_3P(CH_2)_2PO_2(OH)) (2) space group Cc,a=4.6707(2), b=16.9992(6), c=16.7699(6)?,#beta#=98.00(1)deg, R_1(F)=0.0891, while the use ofpropylenediphosphonic acid producesSb(O_3P(CH_2)_3PO_2(OH)) (3) space group P2_1/c,a=4.6635(6), b=19.0545(2), c=8.7608(1)?,#beta#=103.87(4)deg, R_1(F)=0.0352. the structures of 2 and 3are closely related, both revealing open channels in three-dimensional framework architectures.