The reactions of cis-[PtCl 2 L 2 ] [L = PPh 3 , PMe 2 Ph or L 2 = Ph 2 P(CH 2) 2 PPh 2 (dppe)] with endo-8-camphanylphosphonic acid (CamPO 3 H 2) and Ag 2 O in refluxing dichloromethane gave platinum(II) phosphonate complexes [Pt(O 3 PCam)L 2 ]. The X-ray crystal structure of [Pt(O 3 PCam)(PPh 3) 2 ]•2CHCl 3 shows that the bulky camphanyl group, rather than being directed away from the platinum, is instead directed into a pocket formed by the Pt and the two PPh 3 ligands. This allows the O 3 P-CH 2 group to have a preferred staggered conformation. The complexes were studied in detail by NMR spectroscopy, which demonstrates nonfluxional behaviour for the sterically bulky PPh 3 and dppe derivatives, which contain inequivalent phosphine ligands in their 31 P NMR spectra. These findings are backed up by theoretical calculations on the PPh 3 and PPhMe 2 derivatives, which show respectively high and low energy barriers to rotation of the camphanyl group in the PPh 3 and PPhMe 2 complexes. The X-ray crystal structure of CamPO 3 H 2 is also reported, and consists of hydrogen-bonded hexameric aggregates, which assemble to form a columnar structure containing hydrophilic phosphonic acid channels surrounded by a sheath of bulky, hydrophobic camphanyl groups.

analysis and a single-crystal X-ray diffraction study.

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Reaction of the platinum(II) sulfide metalloligand [Pt2(-S)2(PPh3)4] with the tellurium(II) source TeCl2(tu)2 (tu = thiourea) is dependent on reaction conditions employed. In the presence of added acid, the dominant species observed in the Electrospray Ionisation (ESI) mass spectrum is the tetraplatinum species [{Pt2(µ-S)2(PPh3)4}2Te2] 2+. This contains the Te2 2+ moiety and is related to the previously reported tellurium(I) dithiophosphinate analogue [(Ph2PS2)2Te2]. However, in the absence of acid, considerable degradation of the {Pt2S2} metalloligand occurs as evidenced by the formation of the mononuclear complex [Pt{SC(NH2)NH}(PPh3)2] + containing a deprotonated thiourea ligand, together with other thiourea-containing ions, identified by ESI MS. Likewise, attempted use of a fullysubstituted thiourea, viz. Me2NC(S)NMe2 (tmtu) in TeCl2(tmtu)2, also resulted in degradation of the {Pt2S2} core and detection of the known complex [(Ph3P)2PtCl{SC(NMe2)2}] +. The [{Pt2(µ-S)2(PPh3)4}2Te2] 2+ cation was isolated with several anions, and unequivocal confirmation of the structure of the complex was obtained by an X-ray structure determination on the BF4salt, which shows the presence of the Te2 2+ unit, with the Te-Te bond bridged by two {Pt2S2} metalloligands.

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