In this paper we study pattern avoidance for affine permutations. In particular, we show that for a given pattern p, there are only finitely many affine permutations in S̃n that avoid p if and only if p avoids the pattern 321. We then count the number of affine permutations that avoid a given pattern p for each p in S3, as well as give some conjectures for the patterns in S4. This paper is just ...

Reaction of bis(peri-substituted) triphosphine iPrP(AcenapPiPr2)2 (Acenap = acenaphthene-5,6-diyl) with iodine, followed by hydrolysis, afforded ionic species [iPrP(AcenapP(O)iPr2)2] dication, containing P-O-P-O-P motif, balanced triiodide anions. The new were fully characterised, including single crystal X-ray diffraction. formation the unusual double-bridged motif is likely a result crowding ...