Novel investigations of sulfimide systems
thesisposted on 15.02.2011 by Li-Heng (Lee) Fan
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S,S-diphenyl sulfimide (Ph2SNH) has been employed in current investigations divided in three different directions, concerning hydrogen bonding motifs of new sulfimide systems, polymorphism of trans- Cu(Ph2SNH)2Cl2 as well as carboxylations of Ph2SNH. The isomorphic analogues of [Mn(Ph2SNH)6]Cl2 and [Co(Ph2SNH)6]Cl2 were synthesised as parent systems, with their derivatisations by metathesis to give BF4 and PF6 salts. The BF4 daughter systems displayed face on and snug fit hydrogen bonding motifs in the Mn(II) and Co(II) variants respectively. The PF6 analogues were the first examples to have spectator sulfimide units not participating in hydrogen bonds, rationalised as means to relief steric constrains. [Co(Ph2SNH)4]SO4 was observed to be stabilised by the formation of l-D hydrogen bond array between the unsaturated complex centres with SO4 anions. The square planar polymorph of trans- Cu(Ph2SNH)2Cl2 has recently been observed to display reversible mechanochromism when ground. The yielding of a green ground collective was reasoned as the formation of an amorphous conformer closely related to the green pseudotetrahedral polymorph. The concomitant crystallisation of both forms has also been revisited. Internal voids, ether partial pressure and volume of mother liquor have been proposed as contributing factors concerning the crystallisation outcomes. The reaction between Ph2SNH and CO2 led to the formation of [Ph2SNH2]HCO3, Ph2SN(H)COO as well as Ph2SNCOOH, depending on reaction conditions. The zwitterion of Ph2SN(H)COO is expected to be the principle product of Ph2SNH/CO2 reactions, while [Ph2SNH2]HCO3 was deduced as a hydrolysis product of Ph2SN(H)COO. The isolation of Ph2SNCOOH was only possible when CO2 fixation was carried out in DMSO, rationalised as a unique proton transfer equilibrium only attainable in the protophilic solvent.