Synthesis and structural characterization of tube-type tetradecavanadates

By the reaction of ammonium perchlorate with anion-incorporated bowl-type dodecavanadates, viz. [V 12 O 32 ( X )] 5− [ X = N 3 − ( 1 ), OCN − and NO 3 − ], tube-type tetradecavanadates, viz. (NH 4 ) 7 [V 14 O 38 ( X )] [ X = N 3 − ( 2 ), OCN − ( 3 ) and NO 3 − ( 4 )] were synthesized. The crystal structures of penta(tetraethylammonium) azidododecavanadate nitromethane monosolvate, (C 8 H 20 N) 5 [V 12 O 32 (N 3 )]·CH 3 NO 2 , 1 , heptaammonium azidotetradecavanadate dimethyl sulfoxide hexasolvate, (NH 4 ) 7 [V 14 O 38 (N 3 )]·6C 2 H 6 OS, 2 , heptaammonium cyanatotetradecavanadate dimethyl sulfoxide hexasolvate, (NH 4 ) 7 [V 14 O 38 (OCN)]·6C 2 H 6 OS, 3 , and heptaammonium nitratotetradecavanadate dimethyl sulfoxide hexasolvate, (NH 4 ) 7 [V 14 O 38 (NO 3 )]·6C 2 H 6 OS, 4 , were determined. The tube consists of two layers of V 7 rings with a guest anion at the centre. The distances between the incorporated anions and the nearest V atoms are 3.058 (3), 3.039 (6) and 2.811 (9) Å for 2 , 3 and 4 , respectively, showing that the incorporated anions are stabilized via noncovalent interactions. Two ammonium cations cap both ends of the tube to stabilize the structures via hydrogen-bonding interactions. Linear OCN − and N 3 − anions sit on the twofold rotation axes of the tube frameworks and the triangular plane of the NO 3 − anion deviates from the equatorial plane of the tube by ca 30°.