Synthesis and structural characterization of tube-type tetradecavanadates

Abstract

By the reaction of ammonium perchlorate with anion‐incorporated bowl‐type dodecavanadates, viz. [V12O32(X)]5− [X = N3− (1), OCN− and NO3−], tube‐type tetradecavanadates, viz. (NH4)7[V14O38(X)] [X = N3− (2), OCN− (3) and NO3− (4)] were synthesized. The crystal structures of penta(tetraethylammonium) azidododecavanadate nitromethane monosolvate, (C8H20N)5[V12O32(N3)]·CH3NO2, 1, heptaammonium azidotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(N3)]·6C2H6OS, 2, heptaammonium cyanatotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(OCN)]·6C2H6OS, 3, and heptaammonium nitratotetradecavanadate dimethyl sulfoxide hexasolvate, (NH4)7[V14O38(NO3)]·6C2H6OS, 4, were determined. The tube consists of two layers of V7 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 N3− anions sit on the twofold rotation axes of the tube frameworks and the triangular plane of the NO3− anion deviates from the equatorial plane of the tube by ca 30°.

Composition-driven archetype dynamics in polyoxovanadates

“… 72 Theoretically, the sites of unsaturation create destabilisation which motivate further configurational and archetypal rearrangements. 73 “Decoding” the interdependence of these rearrangements is currently very challenging and we are not aware of any broader systematic study. However, rearrangements may be enforced by external factors that enhance stability, crystal packing and conformational adaptability to supramolecular interactions.…”

“…S1d † ) is known to be able to incorporate a monoatomic Cl − , 72 however while its tubular confirmer {V 14 O 38 } (Fig. S1e † ), 73 appears as conformationally more robust structure able to accommodate three and four atomic anions ( e.g. N 3 − , OCN − and NO 3 − ) with higher thermochemical radii.…”

Isolation of a Nitromethane Anion in the Calix-Shaped Inorganic Cage

“…The distance between the central anion and its nearest neighbor vanadium is far from bonding distances, showing that the central anion is floating in the container. Among polyoxometalates composed of VO 5 square pyramids, a 'calix'-shaped dodecavanadate [V 12 O 32 ] 4− (V12) is known [19][20][21][22][23][24][25][26][27][28][29][30]. The broader upper rim consists of eight edge-shared VO 5 pyramids, with a 4.4 Å cavity entrance and a narrow lower rim consisting of four vertex-shared VO 5 pyramids ( Figure 1).…”

“…In the initial stage of the V12 chemistry, the utility is limited to the guest exchange among nitriles because of the strong affinity between the nitrile group and the V12 container [20][21][22]. Recently, we have developed the host-guest chemistry of V12 [23][24][25][26][27][28][29]. By avoiding the usage of the nitrile group in the synthetic procedure by controlling the oxidation state of the vanadium sources, V12 with guest-exchangeability to various electron-rich groups can be prepared [25].…”

“…In the case of Br 2 , Br 2 inserted into V12 is polarized due to the unique charge distribution of the inside of V12, and the peak of the Br−Br vibration is detected in IR at 185 cm −1 [29]. Furthermore, the stabilization of several kinds of anions in V12 has been reported [25][26][27]. The most interesting example is NO − -including V12 [30].…”