[Pt]₂Pb Trinuclear Systems: Impact of the Anionic Platinum Fragment on the Lead Environment and Photoluminescence

Abstract

A comparison of the solid structures of three novel trinuclear sandwich Pt 2 Pb systems (NBu 4 ) 2 [{Pt(C≡CTol) 4 } 2 Pb(OH 2 ) 2 ] 1, [{Pt(bzq)(C≡CPh) 2 } 2 Pb] 2, and (NBu 4 ) [{Pt(bzq)) with that of the previously reported (NBu 4 ) 2 [{Pt(C 6 F 5 ) 4 } 2 Pb] 5 showed that the local environment of Pb II is highly sensitive to the nature of the anionic platinate(II) precursors. The photoluminescence (PL) studies of all 1-5 complexes revealed a dependence of PL on the structure type. Thus, complexes 1 and 5 exhibit metal centered emissions (1, 497 nm, 77 K; 5, 539 nm, φ ) 0.43, 298 K) related to the linear ( 5) or bent (1 Pt-Pb-Pt 149.9°) trinuclear entities. However, in complexes 2-4, that have unprecedented Pb II • • • η 1 (C≡CR) bonding interactions and very short Pt • • • Pb and Pt • • • Pt distances, the emissive state in solid state (77 K) is attributed to a 3 MLM′CT [Pt(1)π(C≡CR)fPt(2)/Pb(sp)π*(C≡CR)] state mixed with some ππ* excimeric character in neutral complexes 2 (R ) Ph) and 3 (R ) C 6 H 4 -CF 3 -4), and in the case of the adduct (NBu 4 )[{Pt(bzq)(C≡CC 6 H 4 -CF 3 -4) 2 } 2 Pb(O 2 ClO 2 )] 4 modified also by Pb II • • • O (O 2 ClO 2 -) contacts.chain. [25][26][27][28][29][30][31][32][33][34][35][36] Furthermore, the alkynyl ligands exhibit a very good π(η 2 ) coordinating capability, and we [37][38][39][40][41][42][43][44][45] and others [46][47][48][49][50][51][52][53] have demonstrated that the luminescence behavior is strongly influenced by perturbation of the electron density of the CtC unit through η 2 • • • metal alkynyl bonding and also by metallophilic interactions. [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] Homo and heteropolynuclear aggregates and clusters based on closed and/or subclosed-shell (d 8 , d 10 , d 10 s 2 ) metallic interactions [54][55][56][57][58] have also been studied as interesting emitters. [59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] The presence of strong metallophilic interactions determines their structures and is often cited as an essential factor of their remarkable photophysical properties. [54][55][56][57][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] The arrangement of the metals and, in particular, the type of metals and coligands have a profound effect on the photophysical behavior of the resulting polynuclear systems. 61,74 Therefore, the controlled formation of novel polymetallic systems of the above metals and the study of their structure property correlations are of great importance in designing functional materials. Within this field, compared to the numerous reports involving polar M-Tl I54,

Unusual Metal–Metal Bonding in a Dinuclear Pt–Au Complex: Snapshot of a Transmetalation Process

“…Geometry optimizations without symmetry constraints were carried out with the Gaussian 09 [5] suite of programs using the BP86 [6] functional in conjunction with the D3 dispersion correction suggested by Grimme and co-workers. [7] Platinum and gold atoms were described using the scalar-relativistic Stuttgart-Dresden SDD effective core potentials and their associated double- basis sets, [8] complemented with a set of polarization functions.…”

Neutral benzoquinolate cyclometalated platinum(II) complexes as precursors in the preparation of luminescent Pt–Ag complexes

“…Metal-metal bonds can act as a link between different subassemblies, making them a valuable tool in molecular or crystal engineering, and giving rise to a variety of structures, from simple linear bimetallic compounds to infinite one-dimensional chains [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Furthermore, some of these complexes show interesting photophysical and photochemical properties [1][2][3][4][5]7,8,11,17,27,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48], which in some cases have been exclusively attributed to the presence ...…”

Reversible Binding of Solvent to Naked PbII Centers in Unusual Homoleptic Alkynyl‐Based Pt2Pb2 Clusters

“…In contrast to d 10 or Tl I ions, investigations on the participation of Pb II in metalophilic interactions are notably sparse, [9] and in particular, its potential in the construction of polynuclear networks supported by alkynyl (s or p) ligands has rarely been investigated. [10] We note that despite the environmental concerns related to lead, its chemistry has attracted much attention in recent years, not only because of the intriguing structural motifs [11] caused by the tuning of the electrochemical activity of the lone pair, but also because of its applications in nonlinear optics, [12] and birefringent, [13] ferroelectric, [14] semiconducting, [15] and luminescent materials.…”

“…[10] We note that despite the environmental concerns related to lead, its chemistry has attracted much attention in recent years, not only because of the intriguing structural motifs [11] caused by the tuning of the electrochemical activity of the lone pair, but also because of its applications in nonlinear optics, [12] and birefringent, [13] ferroelectric, [14] semiconducting, [15] and luminescent materials.…”

“…Unfortunately, the low stability of this complex and the lack of suitable solvate crystals for an X-ray study precluded us from studying the nature of this behavior. [10] In this contribution, we report the preparation and structural characterization of novel intensely luminescent neutral tetranuclear [Pt 2 Pb 2 -(CCR) 8 ] clusters, which display not only vapochromic responses to small donor solvents, but also have mechanochromic properties associated with the remarkable flexibility of the lead centers. In this context, it is worth noting that materials able to respond to more than one external stimulus are now attracting considerable interest.…”