Diverse Evolution of [{Ph₂P(CH₂)_nPPh₂}Pt(μ-S)₂Pt{Ph₂P(CH₂)_nPPh₂}] (n = 2, 3) Metalloligands in CH₂Cl₂

Abstract

The nucleophilicity of the [Pt(2)S(2)] core in [[Ph(2)P(CH(2))(n)PPh(2)]Pt(mu-S)(2)Pt[Ph(2)P(CH(2))(n)PPh(2)]] (n = 3, dppp (1); n = 2, dppe (2)) metalloligands toward the CH(2)Cl(2) solvent has been thoroughly studied. Complex 1, which has been obtained and characterized by X-ray diffraction, is structurally related to 2 and consists of dinuclear molecules with a hinged [Pt(2)S(2)] central ring. The reaction of 1 and 2 with CH(2)Cl(2) has been followed by means of (31)P, (1)H, and (13)C NMR, electrospray ionization mass spectrometry, and X-ray data. Although both reactions proceed at different rates, the first steps are common and lead to a mixture of the corresponding mononuclear complexes [Pt[Ph(2)P(CH(2))(n)PPh(2)](S(2)CH(2))], n = 3 (7), 2 (8), and [Pt[Ph(2)P(CH(2))(n)PPh(2)]Cl(2)], n = 3 (9), 2 (10). Theoretical calculations give support to the proposed pathway for the disintegration process of the [Pt(2)S(2)] ring. Only in the case of 1, the reaction proceeds further yielding [Pt(2)(dppp)(2)[mu-(SCH(2)SCH(2)S)-S,S']]Cl(2) (11). To confirm the sequence of the reactions leading from 1 and 2 to the final products 9 and 11 or 8 and 10, respectively, complexes 7, 8, and 11 have been synthesized and structurally characterized. Additional experiments have allowed elucidation of the reaction mechanism involved from 7 to 11, and thus, the origin of the CH(2) groups that participate in the expansion of the (SCH(2)S)(2-) ligand in 7 to afford the bridging (SCH(2)SCH(2)S)(2-) ligand in 11 has been established. The X-ray structure of 11 is totally unprecedented and consists of a hinged [(dppp)Pt(mu-S)(2)Pt(dppp)] core capped by a CH(2)SCH(2) fragment.

Synthesis and characterization of heterobimetallic complexes with pyridyl selenolato ligands. Crystal structure of [{Pt(C5H4N)(SeC5H4N)(dppp)}ZnCl2]

“…The observed triplet in fact is due to coupling with platinum nuclei. In the complex 2a, the unexpected loss of chalcogen atom is well documented in literature [14,[30][31][32]. For instance, reaction of Zinc metal precursor with [Pt2(P-P)2(μ-S)2] (P-P = PPh3, PMe2Ph, dppp, dppy) did not afford the expected product, instead product [Pt2Cl(P-P)2(μ-S2CH2)]PF6 (P-P = PPh3, PMe2Ph, dppp, dppy) formed by the decomposition of [(P-P)2Pt2(μ3-S)2Zn][PF6]2 in CH2Cl2 [30,32].…”

“…In the complex 2a, the unexpected loss of chalcogen atom is well documented in literature [14,[30][31][32]. For instance, reaction of Zinc metal precursor with [Pt2(P-P)2(μ-S)2] (P-P = PPh3, PMe2Ph, dppp, dppy) did not afford the expected product, instead product [Pt2Cl(P-P)2(μ-S2CH2)]PF6 (P-P = PPh3, PMe2Ph, dppp, dppy) formed by the decomposition of [(P-P)2Pt2(μ3-S)2Zn][PF6]2 in CH2Cl2 [30,32]. Similarly, the bridging thio complex [Pt2(dppf)2(μ-S)2] in dichloromethane solution yields mononuclear compound [Pt(SCH2Cl)2(dppf)] which indicates the formation of terminal bis thiolato complexes from the bridging one [31] .…”

Reaction Chemistry of Complexes Containing PtH, PtSH, or PtS Fragments: From Their Apparent Simplicity to the Maze of Reactions Underlying Their Interconversion

“…The spectroscopic data of the former is described in this work and those of the latter, already obtained by the reaction of [PtCl 2 A C H T U N G T R E N N U N G (dppp)] with Na 2 S·9H 2 O, have been reported elsewhere. [20] On the basis of DFT calculations the proposed reaction pathways from 3 to either 2 or 4 are shown in Scheme 2. The first step, which involves deprotonation of the SH ligand in 3, is common in both pathways.…”

“…However, the same cationic complex as that found in 1 had already been reported as the tetrafluoroborate salt. [15] Spectroscopic data for compounds 1, [15] 3, [16b] 4, [20] [20] and [Pt(SH) 2 …”

Coordination chemistry of the metalloligand [Pt2(μ-S)2(PPh3)4] with nickel(II) complexes – an electrospray mass spectrometry directed synthetic study

“…[1,2] Complexes containing other phosphine ligands such as dppe (Ph 2 PCH 2 CH 2 PPh 2 ) also show similar behaviour, but have been less studied to date. [3] Recently, we have been using the technique of electrospray ionisation mass spectrometry (ESMS) to probe reactions of [Pt 2 (-S) 2 have been summarised in a review. [6] The results from these mass spectrometry studies can then be used to direct subsequent macroscopic syntheses to the more promising reaction systems, thus providing an efficiency of operation, and conserving precious metals.…”