Structural Variation in Silver Acetylide Complexes: Syntheses and X-ray Structure Determinations of [Ph₃PAgC⋮CPh]₄·3.5THF and [Me₃PAgC⋮CSiMe₃]_∞

Abstract

Ph 3 PAgCtCPh] 4 ‚3.5THF (2) can be prepared by the reaction of CpAgPPh 3 (1) with lithium phenylacetylide (1:1 equiv). Similarly [Me 3 PAgCtCSiMe 3 ] ∞ (4) can be prepared by the reaction of CpAgPMe 3 (3) and lithium (trimethylsilyl)acetylide (1:1 equiv). Both complexes have been characterized by elemental analyses, solid-state IR spectroscopy, 1 H and 31 P NMR spectroscopy, and low-temperature X-ray diffraction studies. The structure of 2 consists of a tetranuclear "flat-butterfly" core, with the two "hinge" silver atoms σ-bonded to two acetylide fragments, which then π-complex the apical Ag(PPh 3 ) 2 fragments. In 4, the smaller steric bulk of the phosphine employed allows this complex to crystallize as a polymer. Rather than being constructed from simple [R 3 PAg(acetylide)] units, both 2 and 4 are formed by the aggregation of (acetylide) 2 Agand Ag(PR 3 ) 2 + fragments. The preparation of complexes 2 and 4 demonstrates the synthetic utility of nucleophilic substitution of CpAgPR 3 in the synthesis of Ag organometallics. The different structural alternatives adopted by 2 and 4 point to the steric bulk of the phosphine ligands being the major influence on the structure of Ag acetylide complexes.

Structure Determination of Homoleptic AuI, AgI, and CuI Aryl/Alkylethynyl Coordination Polymers by X‐ray Powder Diffraction

“…The higher energy band at 2052 cm −1 in 4 is ascribed to asymmetric CC stretching due to weak silver–acetylide interactions 31c. All these observed frequencies are comparable with related literature values: 1917 cm −1 in [(PhCCCu) 4 (Ph 2 PCH 2 (CH 2 OCH 2 ) 2 CH 2 PPh 2 ) 2 ],5i 2044 cm −1 in [(PhCCAg) 4 (PPh 3 ) 4 ],32b and 2076 cm −1 in [(PhCCAg) 4 (PCy 3 ) 2 ] 5k. Moreover, considering the similar ν (CC) bands at 1964, 1983 and 2002 cm −1 for the bridging modes in [{( t BuCCAu) 6 } 2 ]7 complex, polymer sheet 5 also possesses two similar broad absorption bands at 2019 and 1985 cm −1 that are assigned to the doubly and triply bridging modes of the complex.…”

“…Unlike the PhCCCu system, structural investigation on the related PhCCAg system remains sparse. A triangular isosceles Ag 3 unit in the [(PhCC) 2 Ag 3 (dppm) 3 ] + complex32a along with the rhombus‐like Ag 4 unit and the square Ag 4 aggregate units in [(PhCCAg) 4 (PPh 3 ) 4 ]32b and [(PhCCAg) 4 (PCy 3 ) 4 ],5k respectively, have previously been reported. In these complexes, Ag⋅⋅⋅Ag contacts (2.866–3.084 Å) dominate throughout these complexes.…”

Molecular and Crystal Structure of Chlorido[2-(N,N,N',N'- tetramethylamidinio)ethynido]silver

“…Organyl silver compounds in general are subject to a broad structural variation [9]; this was documented again in a recent survey of NHC-silver complexes (NHC = Nheterocyclic carbene) [10]. Alkyn-1-yl complexes of silver can form polymers [11,12], aggregates with low nuclearity [12,13], cage compounds with Ag n clusters [14 -16], and 2D and 3D organometallic networks [17 -20]. Solid-state structures with discrete alkynyl silver units appear to be rare [3,21].…”

A Fully Encapsulated Acetylenediide in Ag2C2⋅8 AgF

“…Notably, they are shorter and longer, respectively, than those of silver atoms p-bonded (average 2.452 ) and s-bonded (average 2.057 ) to the CCR groups in the alkynyl complexes [Ph 3 PAgCCPh] 4´3 .5 THF and [Me 3 PAgCCSiMe 3 ] I . [11] The bond angles between the enclosed acetylenediide and individual silver atoms (Ag-C1-C1A) are in the range of 116.2(4) ± 138.4(1)8, and are comparable to those between the C 2À 2 species and ªequato-rialº Ag atoms in Ag 2 C 2´6 AgNO 3 .…”