Synthesis and Reactivity of the Neutral Pyrazolate Complexes [M₂{CH₂C₆H₄P(o-tolyl)₂-κC,P}₂(μ-Rpz)₂] (M = Pd, Pt; Rpz = Pz, 3,5-dmpz, 4-Mepz) toward AgClO₄. Molecular Structure of [Pt₂Ag{CH₂C₆H₄P(o-tolyl)₂-κC,P}₂(μ-4-Mepz)₂]ClO₄

Abstract

The neutral compounds [Pt2{CH2C6H4P(o-tolyl)2-κC,P}2(μ-Rpz)2] (Rpz = pz (2a), 3,5-dmpz (2b), 4-Mepz (2c)) react with AgClO4 in a 1:1 molar ratio to give the trinuclear compounds [Pt2Ag{CH2C6H4P(o-tolyl)2-κC,P}2(μ-Rpz)2]ClO4 (Rpz = pz (4a), 3,5-dmpz (4b), 4-Mepz (4c)), which contain two Pt−Ag bonds. The reaction of [Pd2{CH2C6H4P(o-tolyl)2-κC,P}2(μ-3,5-dmpz)2] (3b) with AgClO4 renders [{Pd2(CH2C6H4P(o-tolyl)2-κC,P)2(μ3-3,5-dmpz-N,N ‘ ,C 4)2Ag(η2-μ2-ClO4)}2] (5), a palladium/silver compound with an unprecedented dmpz bridging ligand η1-bonded to the Ag centers, a coordination mode involving only the C4 atom of each dmpz ligand.

Homo‐ and Heteropolynuclear Platinum Complexes Stabilized by Dimethylpyrazolato and Alkynyl Bridging Ligands: Synthesis, Structures, and Luminescence

“…This fact concerning the structure, that is in line with the lower (C C) vibration observed in the IR spectra (ñ = 1948 in complex 4 as opposed to 2039 cm À1 in complex 3), clearly points to a stronger Au-h 2 (acetylenic) bonding interaction, contrasting with the relatively low number of reported complexes of type bis(h 2 -alkynyl)Au. [103] The PtÀC, [67][68][69][70][71][72][79][80][81] PtÀN, [52,53,[73][74][75][76][77][78] and MÀN bond lengths [37, 38, 43-50, 52, 54, 55, 64, 92, 105-111] are similar to those observed in related pyrazolate complexes.…”

“…The platinum alkynide h 2 linkages are almost symmetrical with the PtÀC a distances only slightly shorter than the corresponding PtÀC b ones. All bond lengths around Pt(1A) and Pt(3A) are in the range of those found for C^P, [78,[112][113][114][115] pyrazolate, [52,53,[73][74][75][76][77][78] and h 2 -alkynyl platinum(ii) complexes. [81,[116][117][118][119] The terminal platinum coordination planes are almost perpendicular to that of the central platinum Pt(2A) plane, the dihedral angles being 79.88 for Pt(1A) and 82.98 for Pt(3A); the dihedral angle between both terminal coordination planes is 27.98.…”

“…[83][84][85] The CuÀN and PtÀN bond lengths are in the range of those found in pyrazolato copper(i) [36-42, 56, 57, 63, 92] and Pt II complexes. [52,53,[73][74][75][76][77][78] As expected [79][80][81] the Pt-C a C b -C Ph units deviate from linearity, this distortion being more pronounced at the C b atom (161.7(6)-167.5 (7)8) and the C a C b bond lengths are slightly elongated with respect to complex 1.…”

“…[72] The PtÀN bond lengths are in the range of those found in Pt complexes with the same type of ligands. [52,53,[73][74][75][76][77][78] The platinum alkynyl units [Pt-C a C b -C Ph ] basically show a linear arrangement with the C a and C b bond angles ranging between 175 and 1808. The monodentate Hdmpz ligands are planar within experimental error and they are oriented almost perpendicularly one to another (the interplanar angle being 75.958) forming, with the platinum coordination plane, an angle of 61.138 (N(1), N(2), C(17), C(18), C (19)) and 65.848 (N(3), N(4), C(22), C(23), C (24)).…”

“…The Pt(2)ÀN and central PtÀC s bond lengths are in the range of those found in related pyrazolate [52,53,[73][74][75][76][77][78] and m,h 2 -alkynyl platinum(ii) complexes, [67][68][69][70][71][72][79][80][81] and the structural details concerning the alkynyl fragments are common for m,h 2 -alkynyl ligands. [79][80][81] The side platinum atoms, Pt(1A) and Pt(3A), exhibit a distorted square-planar environment that is considered to be formed by the C and P donor atoms of the cyclometalated phosphine, the N atom of the bridging dmpz and the midpoint ((X(1A) for Pt(1A), X(1B) for Pt(3A)) of the pbonded C a C b vector; the angles between cis ligands deviate significantly from 908.…”