Cluster Compounds with Oxidised, Hexanuclear [Nb6Cli12Ia6]n− Anions (n=2 or 3). Issue 6 (15th June 2022)

• Record Type: Journal Article
• Authors: Schröder, Florian; Köckerling, Martin
• Is Part Of: ChemistryOpen. Volume 11:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-15
• Subjects: cluster compounds -- halide -- niobium -- redox chemistry -- structure elucidation; Chemistry -- Periodicals; 540; 540.5
• DOI: 10.1002/open.202200063
• Languages: English
• ISSNs: 2191-1363

Abstract

Abstract: Four mixed‐halide cluster salts with chloride‐iodide‐supported octahedral Nb6 metal atoms cores were prepared and investigated. The cluster anions have the formula [Nb6 Cl i 12 I a 6 ] n − with Cl occupying the inner ligand sites and I the outer one. They are one‐ or two‐electron‐oxidized ( n =2 or 3) with respect to the starting material cluster. (Ph4 P) + and (PPN) + function as counter cations. The X‐ray structures reveal a mixed occupation of the outer sites for only one compound, (PPN)3 [Nb6 Cl i 12 I a 5.047(9) Cl a 0.953 ]. All four compounds are obtained in high yield. If in the chemical reactions a mixture of acetic anhydride, CH2 Cl2, and trimethylsilyl iodide is used, the resulting acidic conditions lead to form the two‐electron‐oxidised species ( n =2) with 14 cluster‐based electrons (CBEs). If only acetic anhydride is used, the 15 CBE species ( n =3) is obtained in high yield. Interesting intermolecular bonding is found in (Ph4 P)2 [Nb6 Cl i 12 I a 6 ] ⋅ 4CH2 Cl2 with I⋅⋅⋅I halogen bonding and π‐π bonding interactions between the phenyl rings of the cations in (PPN)3 [Nb6 Cl i 12 I a 5.047(9) Cl a 0.953 ]. The solubility of (Ph4 P)2 [Nb6 Cl i 12 I a 6 ] ⋅ 4CH2 Cl2 has been determined qualitatively in a variety of solvents, and good solubility in the aprotic solvents CH3 CN, THF and CH2 Cl2 has been found. Abstract : Efficient, high yield preparative procedures were developed for mixed chloride‐iodide, hexanuclear niobium cluster salts of the type ( A 2 or A 3 )[Nb6 Cl12 I6 ] ( A =(Ph4 P) + or (PPN) + ). The solid‐state structures, as determined by single‐crystal X‐ray diffraction, show no halide mixing on the inner and outer coordination sites of the octahedral Nb6 core for three of the four salts. They are well soluble in a variety of common solvents, including CH3 CN, THF, and CH2 Cl2 .