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Reactivity of a Monomeric Aluminium Hydrazide towards Isocyanates and Isothiocyanates: Active Lewis Pair Behaviour versus Classical Insertion Reactions
Author(s) -
Uhl Werner,
Bruchhage Julia Silissa,
Willeke Matthias,
Hepp Alexander,
Kösters Jutta
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201600170
Subject(s) - chemistry , hydrazide , dimer , amide , adduct , reactivity (psychology) , medicinal chemistry , monomer , lewis acids and bases , acceptor , stereochemistry , hydride , polymer chemistry , organic chemistry , metal , catalysis , medicine , physics , alternative medicine , pathology , condensed matter physics , polymer
Hydroalumination of H 10 C 5 N–N=C(Ad) with HAl i Bu 2 yielded the hydrazide H 10 C 5 N–N(Al i Bu 2 )Ad ( 4 ; Ad = adamantyl, NC 5 H 10 = piperidinyl). Compound 4 is monomeric and contains a highly strained AlN 2 heterocycle formed by a donor–acceptor interaction between the Al atom and the β‐N atom of the hydrazine. Two equivalents of the hydride afforded an adduct with an HAl i Bu 2 molecule coordinated to 4 by an Al–N and a 3c–2e Al–H–Al bond ( 5 ). t BuN=C=O did not insert into the relatively weak Al←N donor–acceptor bond of 4 ; instead, insertion into the shorter Al–N(amide) bond yielded five‐membered AlN 3 C heterocycle 6 with an exocyclic C=O group. PhN=C=O showed a similar reaction, but the product 7 was dimeric in the solid state with two Al–O bonds. Reaction in a 1:2 ratio afforded a unique linear dimer of phenyl isocyanate, which is stabilised by the aluminium hydrazide ( 8 ). Isothiocyanates gave thiosemicarbazides 9 – 11 , which have Al atoms coordinated in a chelating manner by formation of AlSCN heterocycles and show fascinating differences in their bonding situation.