As stated in the show, the Russians in October 2002 did in fact use a chemical that was intended to knock out terrorists in a Moscow theater holding 800 hostages. The chemical has now been identified as carfentanil which is 100 times more powerful than fentanyl and unfortunately resulted in the death of 120 hostages.
The title is a play on the James Bond novel and film From Russia with Love (1963). In the Bond film series, spanning from Dr. No (1962) to Moonraker (1979), Jonny Lee Miller's grandfather, Bernard Lee, played Bond's boss, M.
When Sherlock is talking to Olga, among the national flags behind them are Jamaica, Bulgaria, Japan, Sri Lanka, the UK, USA (twice), Malaysia, Israel, and North Korea.
The paintings seen in the office aka studio of the chemical restaurateurs are two paintings from The Louvre (Paris, France). One is the 'La Belle Jardinière' (also known as 'Madonna and Child with Saint John the Baptist') by Rafaël and Ridolfo del Ghirlandaio. The other is an enlarged photo of a fragment of 'The Astronomer' by Johannes Vermeer. The full latter painting is 20" by 18" in dimension.