The preparation and characterization of a novel series of cationic sigma-phenylplatinum(II) complexes of the type trans-[Pt(sigma-C(6)H(5))(L)(2)A]OTf (A = picolinic acid, L = PPh(3) (4) and PMePh(2) (7); A = nicotinic acid, L = PPh(3) (5) and PMePh(2) (8); A = isonicotinic acid, L = PPh(3) (6), PMePh(2) (9), and PEt(3) (10)) are described. The pK(a) value for the carboxylic acid functionality in selected complexes was found to follow the order 7 (pK(a) = 5.23 +/- 0.09) > 8 (4.85 +/- 0.10) > 9 (3.51 +/- 0.08) > 6 (3.26 +/- 0.07) approximately 10 (3.21 +/- 0.08) by means of potentiometric titration experiments in 50% (v/v) EtOH/H(2)O solution at 295 K. The X-ray crystal structures of 9 and 10 were also determined. The asymmetric unit of each of 9 and 10 comprises a univalent complex cation, a triflate anion, and a solvent CH(2)Cl(2) molecule of crystallization. Centrosymmetrically related pairs of complex cations in 9 associate via the familiar carboxylic acid dimer motif, whereas with 10, the carboxylic acid dimer motif is absent. Instead, the carboxylic acid residue forms both donor and acceptor interactions to the triflate anion and CH(2)Cl(2) solvent of crystallization, respectively, to afford a 10-membered ring structure. Possible reasons for the observed differences in the solid-state structures of 9 and 10 are presented.

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This paper describes an educational analysis of a first year university chemistry practical called 'Investigating sugar using a home made polarimeter'. The analysis follows the formalism of the Advancing Chemistry by Enhancing Learning in the Laboratory (ACELL) project, which includes a statement of education objectives, and an analysis of the student learning experience. The practical requires students to accurately prepare solutions of known concentrations of a common consumer chemical (sucrose), and then investigate the interaction between these solutions and plane-polarised light. The instrument used is a ''home built'' polarimeter which students assemble, allowing them to recognise that scientific apparatus need not be mysterious in its operation or construction. Student feedback data were conducted using the ACELL Student Learning Experience (ASLE) instrument. Analysis of the data shows that overwhelmingly students rate the experiment as ''worthwhile'' or better. However, many also rate the experiment as ''boring'' or ''uninteresting''. By contrast, staff and student feedback at an ACELL experiential workshop rated the experiment very highly in terms of the ''interest'' criterion. In this contribution we discuss this alignment of staff and student perceptions of various elements, including ''interest'' and explore the correlation with the overall laboratory experience.

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The first examples of adenine binding by isomeric organoplatinum(II) complexes bearing Hbonding nicotinic and isonicotinic acid ligands are reported. Notably, a subtle switching of the H-bonding functionality from the 3-to 4-position of the pyridyl ring leads to a significant change in both the strength of association and the site of adenine binding.